contract no.: tren/07/fp6ae/s07.69061/037191 uvs/publicatii-internationale... · wohlers . klaus ....

Contract no.: TREN/07/FP6AE/S07.69061/037191

INOUI INNOVATIVE OPERATIONAL UAS INTEGRATION

Instrument: STREP (Specific Targeted Research Project)

Thematic Priority: AERO-2005-4.g Open Upstream Research

D1.1 DEFINITION OF THE ENVIRONMENT FOR CIVIL UAS APPLICATIONS

Due date of deliverable: 31/01/2008 Actual submission date: 15/02/2008

Start date of project: 09/10/2007 Duration: 24 months

Organisation name of lead for this deliverable: DFS

Revision: 1.0

Approval status

Author Verification Authority Project Approval DFS DFS DFS

Stefan Tenoort Hans de Jong Achim Baumann

WP 1 Leader INOUI PQC and WP5 Leader INOUI Project Coordinator

15/02/2008 29.02.2008 29.02.2008

Project co-funded by the European Commission within the Sixth Framework Programme (2002-2006)

Dissemination Level PU Public

PP Restricted to other programme participants (including the Commission Services)

RE Restricted to a group specified by the consortium (including the Commission Services)

CO Confidential, only for members of the consortium (including the Commission Services) X

Title: D1.1 Definition of the Environment for Civil UAS Applications

Date: 15/02/2008 Document ID: INOUI_WP1.1_DFS_D1.1_CO_v1.0

Innovative Operational UAS

Integration Revision: 1.0

Dissemination level: Confidential - 2 -

This project has been carried out under a contract awarded by the European Commission. No part of this report may be used, reproduced and/or disclosed in any form or by any means without the prior written permission of the INOUI project partners. © 2007 – All rights reserved

Contributing Partner Company Name DFS Stefan Tenoort, Michael Jung, Andreas Udovic ISDEFE Daniel Cobo BR&TE Carlos Montes ONERA Claude Le Tallec RDE Klaus Wohlers

Distribution List Company Name Company Name European Commission Elisabeth Martin

Document Change Log Rev. Edition date Author Modified

Sections/Pages Comments

0.1 20.11.2007 DFS/ S. Tenoort All Creation of the document 0.2 07.01.2007 DFS/ S. Tenoort All Integration of BRTE, ISD and

DFS contributions 0.3 25.01.2008 DFS/ S. Tenoort All Integration of BRTE, ISD,

ONERA, RDE and DFS contributions

0.4 05.02.2008 DFS/ S. Tenoort 2.1.4, 2.4.3, 2.4.8, 3.1.1, 3.1.2, 3.1.2.1, 3.2.1, 3.2.2, 3.3.3, 3.5.2, Chapter 4: Conclusions, Section 5: Annex

Integrating comments of BRTE, ISD, ONERA, RDE and DFS

1.0 15.02.2008 DFS/ S. Tenoort Clarifying comments and final changes.



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- 3 - Dissemination level: Confidential


Table of Contents

1 Introduction .............................................................................................................................. 8

1.1 Background ....................................................................................................................... 8 1.2 Purpose of the Document.................................................................................................. 9 1.3 Document Structure........................................................................................................... 9 1.4 Applicable and Reference Documents ............................................................................ 10 1.5 Glossary .......................................................................................................................... 12

2 Description of future ATM Environment – ATC Segment .................................................. 14

2.1 Key features of the 2020 ATM Target Concept ............................................................... 15 2.2 ATM Architecture/ Infrastructure...................................................................................... 16 2.3 Future CNS Technologies ............................................................................................... 18

2.3.1 Communication............................................................................................................ 19 2.3.1.1 Mobile Communication ........................................................................................ 20 2.3.1.2 Fixed Communication .......................................................................................... 22 2.3.1.3 The 2020 Communication Baseline ..................................................................... 22

2.3.2 Navigation.................................................................................................................... 23 2.3.2.1 The 2020 Navigation Baseline............................................................................. 26

2.3.3 Surveillance ................................................................................................................. 26 2.3.3.1 The 2020 Surveillance Baseline .......................................................................... 33

2.3.4 Risk and Recommendations........................................................................................ 34 2.4 ATM Operations - objectives and means......................................................................... 35

2.4.1 Airspace organisation and management ..................................................................... 35 2.4.1.1 Current Situation.................................................................................................. 35 2.4.1.2 Airspace related Air Traffic Services (ATS) ......................................................... 40 2.4.1.3 Future Airspace Situation as defined in SESAR.................................................. 47

2.4.2 En-route and Approach ATC ....................................................................................... 51 2.4.3 Aerodrome ATC........................................................................................................... 54 2.4.4 Airport Operations........................................................................................................ 56 2.4.5 Flow management ....................................................................................................... 57 2.4.6 Development & Management of the Network Operations Plan ................................... 61 2.4.7 SWIM........................................................................................................................... 61 2.4.8 Airspace users ............................................................................................................. 64







3 Description of ATM Environment – UAS Segment..............................................................68

3.1 SES Architecture and Airspace Users .............................................................................68 3.1.1 Airspace User Operations Centre (AOC).....................................................................68 3.1.2 Aircraft..........................................................................................................................69

3.1.2.1 Communications ..................................................................................................69 3.1.2.2 Navigation ............................................................................................................70 3.1.2.3 Surveillance..........................................................................................................70

3.2 UAS operating in the airspace .........................................................................................71 3.2.1 Current airspace classification .....................................................................................71 3.2.2 UAS pilot’s functions ....................................................................................................73 3.2.3 Operation modes .........................................................................................................73

3.2.3.1 Mode #1: Visual Line Of Sight 1 (VLOS1)...........................................................74 3.2.3.2 Mode #2: Visual Line Of Sight 2 (VLOS2)............................................................75 3.2.3.3 Mode #3: Line Of Sight (LOS)..............................................................................75 3.2.3.4 Mode #4: Beyond Line Of Sight (BLOS) ..............................................................76

3.2.4 2020 airspace classification .........................................................................................77 3.3 Tentative UAS operational categorisation........................................................................77

3.3.1 Rationale......................................................................................................................77 3.3.2 Proposed categorisation ..............................................................................................78 3.3.3 Comments on the proposed categorisation .................................................................80 3.3.4 Systematic approach ...................................................................................................81

3.4 UAS ATM concept, from the current situation to 2020.....................................................85 3.5 UAS Functional Architecture: High-Level Functions (HLF) and sub-functions ................85

3.5.1 HLF-1: ‘Aviate’ .............................................................................................................86 3.5.1.1 Provide Flight Forces and Stability.......................................................................87 3.5.1.2 Maintain Structural Integrity .................................................................................88 3.5.1.3 Control Flight Path (FP) /Attitude .........................................................................88 3.5.1.4 Control Ground Path (GP)....................................................................................88 3.5.1.5 Control Air/Ground Transition (AGT)....................................................................89 3.5.1.6 Command & Control (C2) the UAS.......................................................................89 3.5.1.7 Control UAS Sub-systems and Stability...............................................................90

3.5.2 HLF-2: ‘Navigate’ .........................................................................................................90



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3.5.2.1 Convey Navigation state...................................................................................... 91 3.5.2.2 Determine Navigation intent................................................................................. 91 3.5.2.3 Produce Navigation command............................................................................. 92 3.5.2.4 Determine Navigation command status ............................................................... 92

3.5.3 HLF-3: ‘Communicate’ ................................................................................................. 92 3.5.3.1 Transmit information to ATC and other aircrafts .................................................. 92 3.5.3.2 Receive information from ATC and other aircrafts............................................... 93

3.5.4 HLF-4: ‘Mitigate’........................................................................................................... 93 3.5.4.1 Avoid collisions .................................................................................................... 94 3.5.4.2 Avoid adverse environmental conditions ............................................................. 95 3.5.4.3 Manage contingencies......................................................................................... 95

4 Conclusions............................................................................................................................ 97

5 Annex A: Definitions............................................................................................................ 100







List of Figures

Figure 2-1 High level European ATM System 2020 logical architecture (SESAR 2007) ...........17 Figure 2-2 Schematic TIS-B network.........................................................................................32 Figure 2-3 Airspace structure and visual flight rules in Germany ..............................................38 Figure 2-4 French airspace around Paris and Toulouse............................................................39 Figure 2-5 Airspace Classification ECAC States 2007 (Eurocontrol 2007) ...............................40 Figure 2-6 SESAR airspace structure........................................................................................48 Figure 2-7 UAS Integration into Managed Airspace ..................................................................50 Figure 2-8 UAS Integration into Unmanaged Airspace..............................................................51 Figure 2-9 Departure/Arrival routes for high-complexity terminal area using cones ..................55 Figure 2-10 Departure/Arrival routes for high-complexity terminal area using tubes...................55 Figure 2-11 Traffic flow planning .................................................................................................61 Figure 2-12 Conventional structure vs. SWIM enabled system...................................................63 Figure 3-1 UAS Separation Assurance and Collision avoidance...............................................72 Figure 3-2 UAS mission enabling visual contact operations ATC-pilot communications

relayed through the UAV ..........................................................................................74 Figure 3-3 UAS mission enabling visual contact operations Direct ground ATC-pilot

communications link .................................................................................................74 Figure 3-4 UAS mission enabling visual contact operations (ACS) ...........................................75 Figure 3-5 UAS mission enabling LOS data link operations (GCS)...........................................76 Figure 3-6 UAS mission requiring a satellite relay (BLOS) ........................................................77 Figure 3-7 Operational categories based on the UAS capabilities ............................................78 Figure 3-8 UAS High Level Functions (HLF) .............................................................................86 Figure 3-9. UAS HLF-1: ‘Aviate’ ......................................................................................................87 Figure 3-10 UAS HLF-2: ‘Navigate’ .............................................................................................91 Figure 3-11 UAS HLF-3: ‘Communicate’ .....................................................................................92 Figure 3-12 UAS HLF-4: ‘Mitigate’ ...............................................................................................94



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List of Tables

Table 2-1 Communication technologies according to SESAR D3............................................ 20 Table 2-2 Navigation technologies according to SESAR D3.................................................... 24 Table 2-3 Surveillance technologies according to SESAR D3 ................................................. 28 Table 2-4 ICAO airspace classification .................................................................................... 37 Table 2-5 Airspace and ATS .................................................................................................... 43 Table 2-6 Eurocontrol specifications for the use of military UAV as operational air traffic

outside segregated airspace [5] ............................................................................... 44 Table 5-1 Definitions used in INOUI....................................................................................... 100







1 Introduction 1.1 Background

The INOUI project is a response to the challenge of integrating UASs as new airspace users (besides Business Aviation, General Aviation and Military Aviation) into the future ATM system.

The project is related to the Research Domain 4.g « Innovative Air Traffic Managment Research » of the FP6-2005-AERO-4, Research Area « Open Upstream Research ».

The driving force behind creating the INOUI project is stemming from the fact that UAS operations will be more and more demanded by organizations, institutions, corporations and the society in general, and thus, they will need to operate in the airspace as another airspace user. Regardless of the fact that UAS are already conquering the skies, although either at a very low altitude, or in segregated airspace due to their mostly military nature, the integration in the non-restricted airspace is left aside. In particular, the topic UAS is almost totally absent from SESAR and its high-level Definition Phase (Phase I). INOUI aims at complementing SESAR to compensate for this flaw of leaving out UASs. This will be achieved by developing documents providing a roadmap to the future of UASs in the context of the ever changing ATM environment.

The long-term targets of SESAR have been defined as political vision and goals for the design of the future ATM System, and as EC objectives of the SESAR programme. They are to achieve a future European Air Traffic Management (ATM) System for 2020 and beyond which can, relative to today’s performance:

• Enable a threefold increase in capacity which will also reduce delays, both on the ground and in the air;

• Improve the safety performance by a factor of 10; • Enable a 10% reduction in the effects flights have on the environment and • Provide ATM services at a cost to the airspace users which is at least 50% less.

The relationship with SESAR is clear since INOUI considers it as one of the main references for its work, as SESAR defines the common future ATM system in Europe.

The real challenge for INOUI is to propose procedures to integrate the operation of UAS in an oversaturated airspace. It is forecast that air traffic will grow up three times the current figures. And this is without UAS on it. Thus UAS operation will suppose an additional increase in the air traffic volume, it is INOUI task to assess the feasibility of using these new operational solutions also with the UAS and its impact, or proposing new operational solutions in order to not jeopardize the performance of the future ATM system.

INOUI defines an operational concept, proposes operational procedures and assess the technologies to support them in order to facilitate the integration of the UAS in the airspace and airport paradigm foreseen by 2020 and beyond. The overall objective of INOUI is to assess different domains of the ATM system of today and 2020 to develop a roadmap how to integrate UASs into the operational concept for the future. This activity will complement



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the activities of the SESAR definition phase and fill the gaps with regard to the specifities of UASs.

1.2 Purpose of the Document

This document is the first deliverable of WP 1. The purpose of D1.1 “Definition of the ATM Environment for UAS in 2020” is an analysis of the future ATM system. The changes in environment of air traffic management from today up to 2020 shall be described in the scenario analysis of this work package, thus to identify the operational scenario for UAS integration.

WP 1.1 deals with following issues:

• Description of the ATC segment, by analysing the foreseen changes in the ATM system, mainly driven by SESAR.

• Description of the UAS segment

1.3 Document Structure

This document is divided into the following sections:

Section 1 – Introduction

Section 2 – Description of future ATM Environment – ATC Segment

Section 3 – Description of ATM Environment – UAS Segment

Section 4 – Conclusions

Section 5 – Annex A: Definitions







1.4 Applicable and Reference Documents

N° Title Reference Date

[1] INOUI (2007), Annex I - Description of work

[2] SESAR Consortium (2007), D3 – The ATM Target Concept, Brussels

[3] SESAR Consortium (2006), D1 - Air Transport Framework The Current Situation, Brussels

[4] SESAR Consortium (2007), The ATM Target Concept - Deliverable 3 at a glance, Brussels

[5]

EUROCONTROL (2007), Eurocontrol Specifications for the Use of Military Unmanned Aerial Vehicles as Operational Air Traffic outside Segregated Airspace, Brussels

EUROCONTROL-SPEC-0102 03/12/2007

[6] Functional Requirements Document for HALE UAS Operations in the NAS (Step 1). Access 5 (NASA & UNITE).

ACCESS 5 – FRD - Version 3 01/2006

[7] Preliminary Considerations for Classifying Hazards of Unmanned Aircraft Systems NASA/TM-2007-214539 02/2007

[8] ICAO – International Civil Aviation Vocabulary ICAO Doc 9713 (3rd edition) 01/01/2007

[9] ICAO – Global Air Traffic Management Operational Concept ICAO Doc 9854 (1st edition) 04/01/2005

[10] EUROCONTROL – EATM Glossary of terms N/A 09/06/2004

[11] JAA/EUROCONTROL UAV Task Force – Concept for European Regulations for Civil Unmanned Aerial Vehicles – Final Report

UAV Task Force (Final Report) 11/05/2004

[12]

RTCA-SC203 – Guidance Material and Considerations for Unmanned Aircraft Systems – Appendix B: Terminology and Acronyms

RTCA DO-304 (Appendix B) 22/03/2007

[13] FAA Pilot/Controller Glossary PCG 30/08/2007

[14] DoD Dictionary of Military and Associated Terms DoD Joint Publication 1-02 17/10/2007

[15] US DoD – Airworthiness Certification Criteria MIL-HDBK-516B 26/09/2005



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N° Title Reference Date

[16] Links to the Single European Sky (SES)

http://ec.europa.eu/transport/air_portal/traffic_management/index_en.htm http://www.eurocontrol.int/ses/

N/A1

[17] Links to the Single European Sky ATM Research (SESAR)

http://www.sesar-consortium.aero http://www.eurocontrol.int/sesar/ http://ec.europa.eu/transport/air_portal/sesame/index_en.htm

N/A1

[18] USICO

1: Note that links may be changed or retrieved at any time without warning by the responsible organizations

http://ec.europa.eu/transport/air_portal/traffic_management/index_en.htm



http://www.eurocontrol.int/ses/

http://www.sesar-consortium.aero/

http://www.sesar-consortium.aero/

http://www.eurocontrol.int/sesar/

http://ec.europa.eu/transport/air_portal/sesame/index_en.htm

http://ec.europa.eu/transport/air_portal/sesame/index_en.htm







1.5 Glossary

4D Four Dimensions ABAS Aircraft Based Augmentation System ACARE Advisory Council for Aeronautics Research in Europe ACAS Airborne Collision Avoidance System ACC Area Control Centre ADF Automatic Direction Finder ADS-B Automatic Dependent Surveillance Broadcast AFTN Aeronautical Fixed Telecommunication Network AMHS Aeronautical Message Handling Service ANSP Air Navigation Service Provider ASAS Airborne Separation Assistance (Assurance) Systems A-SMGCS Advanced Surface Movement Guidance and Control System ATC Air Traffic Control ATCO Air Traffic Controller ATFCM Air Traffic Flow and Capacity Management ATM Air Traffic Management ATN Aeronautical Telecommunications Network BR&TE Boeing Research and Technology Europe SL C2 Command and Control C3 Command, Control and Communication CAATS Cooperative Approach to ATS CASCADE Co-operative ATS through Surveillance and Communication Applications

Deployed in ECAC C-ATM Collaborative ATM CDM Collaborative Decision Making CFMU Central Flow Management Unit CNS Communication, Navigation, Surveillance CPDLC Controller Pilot DataLink Communication DB Data Base DFS DFS Deutsche Flugsicherung GmbH DME Distance Measuring Equipment DVP Development Plan EC European Commission ECAC European Civil Aviation Conference EGNOS European Geostationary Navigation Overlay System Services ESARR EUROCONTROL Safety Regulatory Requirement EU European Union EUROCAE European Organization for Civil Aviation Electronics EUROCONTROL European Organisation for the Safety of Air Navigation EVS Enhanced Vision System FCS Flight Control System FIR Flight Information Region FMS Flight Management System FP Framework Programme FPL Flight Plan



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G2G Gate To Gate GAT General Air Traffic GBAS Ground Based Augmentation System GLONASS GLObal'naya NAvigatsionnaya Sputnikovaya Sistema

(Global Navigation Satellite System) GNSS Global Navigation Satellite System GPS Global Positioning System HUD Head-Up Display ICAO International Civil Aviation Organisation IFATS Innovative Future Air Transport System IFR Instrumental Flight Rules ILS Instrument Landing System INA Innaxis – Fundació Instituto de Investigación ISD Isdefe – Ingeniería de Sistemas para la Defensa de España JPALS Joint Precision Approach and Landing Systems LED Light Emitting Diode MLAT Multi Lateration MLS Microwave Landing System MMR Multi Mode Receiver MSPSR Multi Static Primary Surveillance Radar NDB Non-Directional Beacon OAT Operational Air Traffic ONERA Office National d’Etudes et de Recherches Aéronautiques PCO Project Co-ordinator PMP Project Management Plan PSR Primary Surveillance Radar RCS Radar Cross Section RDE Rheinmetall Defence Electronics GmbH SATCOM Satellite Voice and Data communications SBAS Satellite-Based Augmentation System SES Single European Sky SESAR Single European Sky ATM Research Programme SMGCS Surface Movement Guidance and Control System SSR Secondary Surveillance Radar TIS-B Traffic Information Service - Broadcast TMA Terminal Manoeuvring Area UAC Upper Area Control Center UAS Unmanned Aerial Systems UAV Unmanned Aerial Vehicles UIR Upper Flight Information Region VDL VHF (Very High Frequency) Datalink VFR Visual Flight Rules VHF Very High Frequency VOR VHF Omni-directional Radio Range WAAS Wide Area Augmentation System WAM Wide Area Multi-lateration WG Working Group WP Work Package WRC World Radio communication Conference







2 Description of future ATM Environment – ATC Segment In 2004 the European Commission launched the Single European Sky legislation (SES), which set the political frame for action in Europe to support the need for doubling ATM capacity by 2020. The Single European Sky was drafted with the following objectives:

• to restructure European airspace as a function of air traffic flows, rather than according to national borders

• to create additional capacity; and • to increase the overall efficiency of the air traffic management system.The

European Commission’s ATM legislative package of four regulations covers the essential regulatory elements to be developed in order to achieve a seamless European Air Traffic Management System. They are:

• A Framework for the Creation of the Single European Sky.The Provision of Air Navigation Services.The Organisation and Use of Airspace.The Interoperability of the European Air Traffic Management NetworkTo make the Single European Sky

become a reality the SESAR programme was started. The SESAR programme is the European Air Traffic Management (ATM) modernisation programme. It aims at developing the new generation air traffic management system capable of ensuring the safety and fluidity of air transport worldwide over the next 30 years. It will combine technological, economic and regulatory aspects and will use the Single European Sky (SES) legislation to synchronise the plans and actions of the different stakeholders and federate resources for the development and implementation of the required improvements throughout Europe, in both airborne and ground systems.

SESAR is a three phase project. A definition phase (2004-2008) followed by a development phase (2008-2013) and finally a deployment phase (2013-2020). The first phase of SESAR, the definition phase, is co-funded by EUROCONTROL and the European Commission under Trans European networks. It aims at proposing concrete actions and measures to plan, research, validate, develop and support the implementation of the SES. It will ultimately deliver the shared air transport industry ATM Master Plan covering the period up to 2020. The ATM Master Plan is defining the content, the development and deployment plans of the next generation of ATM systems.

The SESAR Definition Phase will produce 6 main Deliverables covering all aspects of the future European ATM System, including its supporting institutional framework. The scope of the 6 Deliverables, of which D1 –D3 have already been published, are:

• D1: Air Transport Framework – the current situation • D2: Air Transport Framework – the Performance Target • D3: Definition of the future ATM Target Concept • D4: Selection of the “Best” Deployment Scenario • D5: Production of the ATM Master Plan • D6: Work Programme for 2008 -2013



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In 2008, the definition phase will be completed. This will trigger the start of the next phase: the implementation phase, decomposed into a development phase and a deployment phase.

In SESAR D3 the future ATM Target Concept was developed. It delivers the Concept of Operations (ConOps), System Architecture and the Technologies enablers. Hence this is the foundation of the future ATM system in Europe.

2.1 Key features of the 2020 ATM Target Concept

Business Trajectory This is a 4D Trajectory which expresses the business intention of the airspace user for a specific flight with or without constraints. For military users the business trajectory corresponds to a mission trajectory. The concept places the business trajectory at the core of the system with the aim to execute each flight as close as possible to the intention of its owner:

• Air traffic management services will ensure that it is carried out safely and cost efficiently within the infrastructural and environmental constraints;

• Changes to the Business Trajectory shall be kept to a minimum, except in time critical situations;

• Business Trajectories are expressed in all 4 dimensions (position and time) and flown with much higher precision than today.

Trajectory Management This is introducing a new approach to airspace design and management, where the focus is moving from airspace to trajectory management.

• Airspace Users fly preferred routing without pre-defined routes;

• Structured routes will only be activated where and when needed to enable the required capacity, e.g. in congested TMAs (Terminal Manoeuvring Areas);

• The needs of the Military are safeguarded;

• It is considered that no other segregation is required;

• Only two categories of airspace are defined and organised: managed airspace where separation service is provided by ANSPs (it may in some cases be delegated to the pilot) and unmanaged airspace where the pilot carries out the separation task.

Collaborative Planning continuously reflected in the Network Operations Plan (NOP):

This shall balance capacity and demand.

• All main stakeholders collaborate in a layered planning approach to establish the NOP;

• The collaborative planning ensures that capacity matches demand;

• It enables efficient queue management, optimizing access to constrained resources;

• It minimises holding and ground queues;







• It enables priority setting by Airspace Users in the event of a capacity shortfall.

Integrated Airport operations contributing to capacity gains and reducing the environmental impact:

Airports will become an integral part of the ATM system due to the extension of trajectory management.

• Full integration of airport operations into the trajectory management processes;

• Increased throughput and reduced environmental impact (via e.g. turnaround management, reduction of the impact of low visibility conditions, etc.).

New separation modes to allow for increased capacity:

• New separation modes gradually being implemented over time will use trajectory control and airborne separation systems to minimize potential conflicts and controllers’ interventions;

• Supported by controller and airborne tools like ASAS (Airborne Separation Assurance Systems) and ACAS (Airborne Collision Avoidance System).

System Wide Information Management – integrating all ATM related data:

• A System Wide Information Management (SWIM) environment including all ATM actors, e.g. aircraft and ground facilities, will underpin the future ATM system.

• It supports CDM processes using efficient end-user applications to exploit the power of shared and up to date information.

Humans will be central in the future European ATM system as managers and decision-makers:

• To accommodate the expected traffic increase, an advanced level of automation support for the humans will be required

• The nature of human roles and tasks will necessarily change. This will affect system design, staff selection, training, competence requirements and relevant regulations.

2.2 ATM Architecture/ Infrastructure

Air Traffic Management (ATM) is defined by ICAO as: “The aggregation of the airborne functions and ground-based functions (air traffic services, airspace management and air traffic flow management) required to ensure the safe and efficient movement of aircraft during all phases of operations“. An ATM system provides ATM through the collaborative integration of humans, information, technology, facilities and services, supported by air, ground and/or space-based communications, navigation and surveillance. (ICAO ATMCP – Air Traffic Management Operational Concept Panel).

Figure 2-1 presents the high level logical architecture of the ATM system as considered in SESAR D3. It consists of the three main components ATM Operations, ATM Support and



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ATM Shared Concepts, each representing functions and information to be managed by the ATM system.

Meteo

En-route/APP ATC

AirportOperations

Airspace Organisation & Management

ATFCMAirspace

User Operations

Aerodrome ATC

Air Surveillance

Surface Surveillance

Aircraft Navigation

Aircraft Surveillance

ATM

Sup

port

ATM Operations

Ground Communication


ATM Shared Concepts

Flight Airspace Organisation Aerodrome Navigation

AidsAircraft

Distributed System Services (Middleware)Aircraft Communication

Meteo

En-route/APP ATC

AirportOperations

Airspace Organisation & Management

ATFCMAirspace

User Operations

Aerodrome ATC

Air Surveillance

Surface Surveillance

Aircraft Navigation

ATM

Sup

port

ATM Operations

Ground Communication

Aircraft Surveillance

ATM Shared Concepts

Flight Airspace Organisation Aerodrome Navigation

Aids

Distributed System Services (Middleware)Aircraft Communication

Aircraft

Figure 2-1 High level European ATM System 2020 logical architecture (SESAR 2007)

ATM Operations contain the core ATC elements and provides direct support for the main actors of the system. The architecture reflects the organisational structure of ATM and covers En-route and Approach ATC, Aerodrome ATC, Airport Operations, Airspace User Operations, Air Traffic Flow and Capacity Management, and Airspace Organisation and Management.

The Air Traffic Control (ATC) task is to provide safe, efficient and orderly flow of air traffic. The service is provided by Air Traffic Controllers working at airports for the arrival and departure flight phases and in Air Traffic Control Centres for the en-route flight phase (see chapters 2.4.2 and 2.4.3).

The Air Traffic Flow and Capacity Management (ATFCM) is responsible for the strategic (long term) planning of the air traffic including pre-tactical and tactical activities to match demand and capacity (see chapter 2.4.5).

The Airspace Organisation and Management establishes airspace structures in order to accommodate the different types of air activity, the volume of traffic and the differing levels of service. The primary objective is to maximise the utilisation of available airspace by dynamic time-sharing and by segregating airspace among various categories of users based on short-term needs and to plan airspace usage in a way that balances the impact on civil air traffic flow and capacity management with military needs. Airspace organisation and management is described in chapter 2.4.1.

Airport Operations are related to the ground infrastructure and is aimed at supporting the planning and monitoring of airport resource usage (stands, de-icing areas) and services to aircraft operators (stand allocation, passenger handling, luggage handling, and refuelling, catering, towing). Airport operations are described in chapter 2.4.4.







Airspace Users Operations concerns the ATM related aspects of flight operations including Flight Planning, Flight Briefing, Aircraft Management, Fleet Management, Operations Management, and Schedule Management. These kinds of operations have differences in planning horizons from “scheduled well in advance” to “just prior to the flight becoming active”, depending on the nature of the airspace user (e.g. civil commercial, GAT, military). Airspace users are portrayed in chapter 2.4.8.

ATM Support provides the services to support the ATM Operations and covers Communication, Navigation (Aircraft Navigation), Surveillance (Aircraft Surveillance, Air Surveillance and Ground Surveillance). CNS is the key enabler for air traffic control. In the following section 2.3 the CNS technologies foreseen in the future (2020) are described.

ATM Shared Concepts contains the common services that are used by more than one kind of organisation to access certain information. The shared elements cover Flight, Aircraft, Airspace Organisation, Navigation Aids, Aerodrome and Meteo. The Aeronautical Information Service Provider is directly linked to the Shared Elements for ensuring consistency and distribution.

The element Flight is related to planning and conducting a flight, i.e basic flight information, flight plan management (creation, deletion and access to the known set of flights), flight profile and trajectory, constraints applicable to a flight.

The Aircraft element contains the aircraft characteristics like aircraft description/ categorisation, equipment, performance, operating preferences, etc.

The Airspace Organisation contains all specific elements which describe the overall structure of the airspace. Therefore it addresses routes structure and geography, airspace sectorisation and capacity and significant points which all together make up the description of the airspace.

The Navigation elements contain the entities (type, name, location, etc.) of available navigation aids like VOR (VHF Omni-directional Radio beacon), NDB (Non-Directional Beacon), ILS (Instrument Landing System), etc.

The Aerodrome part describes the aerodrome in a broader sense with type of aerodrome, geographical and structural entities (layout of runways, taxiways and apron), its configuration and operation mode, and infrastructure, etc.

Meteo Service Providers have the responsibility to forecast, observe, provide and collect enroute and airfield weather forecasts and the corresponding actual weather reports for all parties dealing with flight planning and flight operations.

2.3 Future CNS Technologies

This chapter highlights the CNS technology necessary to support the ATM Concept of Operations (ConOps) and ATM architecture for 2020 and beyond as described by the SESAR consortium. These candidate technologies were assessed by the SESAR stakeholders against operational and architecture needs, and deployment considerations. A



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common objective is a continuous and balanced evolution of CNS technology from now to 2020, and beyond to support the ATM ConOps. Some of the technologies necessary to support the ConOps are already implemented or are planned to be implemented.

In SESAR D3 it is explicitly stated, that “Specific technologies needed for UAV/UAS to ensure a transparent operation similar to a manned aircraft (e.g. dedicated high integrity UAV/operator command and control datalinks, sense and avoid technologies, advanced onboard automation) fall outside SESAR.” However it is conceivable that certain technologies developed in the future by and for the UAS community will find their way to manned aircraft. E.g. there seem to be requirements of advanced business aviation seeking for sense and avoid technologies in the not to far future.

In its simplest form, the 2020 CNS baseline can be characterised as follows:

• Communication technologies that enable improved voice and data exchanges between service actors within the system, such as those necessary to support the SWIM functionality and CDM process (see chapter 2.3.1).

• Navigation technologies that enable precision positioning, timing and guidance of the aircraft to support high performance, efficient 4D trajectory operations in all phases of flight (see chapter 2.3.2).

• Surveillance technologies that enable precision monitoring of all traffic to assure safe and efficient operations, including enhanced Traffic Situational Awareness and Airborne Separation Assurance Systems ASAS, as well as technologies enabling weather or obstacles surveillance (see chapter 2.3.3).

2.3.1 Communication

The expected increasing need of data exchange between ATM stakeholders is an important driver for an evolution from analogue to digital communications capabilities and technology. With the increasing use of data communication, voice will become an ultimate backup means as regarded by the SESAR consortium.

The aeronautical communications infrastructure is traditionally divided into two parts, the air-to- ground and ground-to-ground infrastructure, also characterized as fixed and mobile communications. The following Table 2-1 depicts the initial candidate technologies analysed in SESAR D3 that meet the high level needs for communication in the future for the sub-elements of each part.







Table 2-1 Communication technologies according to SESAR D3

Terrestrial

SAT

Airp

ort

Ground-Ground network

Communication technologies

Communication needs VH

F (2

5 kH

z an

d 8.

33 k

Hz)

VDL2

(VH

F da

talin

k)

ATN

(Aer

onau

tical

Tel

ecom

m. N

etw

ork

Mob

ile IP

B-A

MC

(Bro

adba

nd V

HF)

P-34

Wid

eban

d C

DM

A

AM

AC

S

Nar

row

band

LD

L

SATC

OM

802.

1 (C

-Ban

d)

V-SA

T

PEN

S IP

V6

Tran

spor

t Lay

er

AM

HS

Voic

e O

ver I

P

ATS

Qsi

g

1. Mobile Communications Air-Ground: ATS & AOC data

Air-Ground Voice Network Management Air-Air Datalink Air-Air Voice

2. Fixed Communications Ground-Ground Datalink Ground-Ground Voice Comunications

2.3.1.1 Mobile Communication

The mobile communication technology shall provide air-to-ground and air-to-air voice and data services.

Voice Services

It is highly likely that voice will remain an essential means of communication at least until the 2020 timeframe. Voice services are expected to continue on the principle of one channel per controller, respectively per sector. Beyond 2020, and as defined by the ConOps, voice will remain the primary means of communications only in certain circumstances. The role of voice communications will then essentially be a safety back-up means.

In the near term, air traffic control operations and aeronautical operations control (AOC) will continue to use the allocated VHF spectrum (118-137 MHz) for voice communications. In order to service continued demand for additional voice channels, Europe has implemented



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8.33 kHz channel spacing in the VHF band in designated airspaces. With the expected traffic increases, it will be necessary to extend the deployment of 8.33 kHz in managed airspace and progressively remove UHF(military) and 25kHz channel spacing. In order to enable a transition for general aviation (GAT), state and military aircrafts (OAT), and to cater for the situation where retrofit or upgrade is not practicable, VHF 25 kHz and UHF will need to be maintained as long as necessary in some parts of the airspace. The provision of UHF voice complementary to accommodate non-compatible military aircraft must be limited to meeting the OAT requirements. The military fleet will be progressively fitted with 8.33 kHz VHF radios. However, it is predicted that within 10 years the ongoing demand for voice channels cannot be satisfied in the presently allocated VHF band even after full deployment of the 8.33 kHz spacing (SESAR 2007)

The voice service for 2020 will be complemented by Satellite Voice and Data communications (SATCOM) for oceanic and remote areas. The use of SATCOM voice could start at the earliest in 2013 and could be completed in 2020. SATCOM voice will become the primary means with VHF retained as a backup.

Data Services

In SESAR it is foreseen that data exchange via datalink will be progressively introduced for routine communications. For that type of communication various technologies are possible. Basically the driver for choosing and implementing a specific datalink technology is the higher performance required to support advanced services, such as 4D contract, trajectory exchanges, as well as increasing air-traffic volumes and density. These performance requirements are mainly predictability, security, latency, availability, integrity and throughput. Furthermore major constraints for any datalink technology are the radiofrequency spectrum availability and aircraft equipment cohabitation. However it has to be considered that due to World Radio Conference (WRC) decisions, different frequency bands are used in different radio areas, i.e. regions in the world. This will pose additional challenge for the interoperability of UAS equipage.

In the near term air-ground datalink services will be based on ATN/VDL Mode2 technology (Aeronautical Telecommunications Network/ VHF Datalink). To fully support the ATM Target Concept this technology will need to be improved or complemented. To meet the long-term data communication needs, e.g. 4D contract and trajectory exchanges with a high number of airspace users, a dual link system is expected to be necessary to cope with the increased availability requirements.

Additionally the foreseen separation and self-separation applications like ASAS and ACAS require Air-Air data communications. The new terrestrial datalink component (L-band technology; frequency spectrum of 1-2 GHz) is the candidate to support them. However, today operational performance requirements for this datalink are not available, and thus, they need to be developed expeditiously if this enabler is to be deployed within the expected timeframe.

The final mobile data communication infrastructure will be a set of four components to support the data communication needs necessary to support the SESAR ATM Target concept:







• New L band terrestrial data-link; • Satellite data-link, to complement the terrestrial data-link and provide necessary

performance; • Airport data-link based upon WIFI technology (IEEE 802.16e), to provide a high

performance airport surface data link; • VDL2/ATN (VHF Datalink 2/ Aeronautical Telecommunications Network).

2.3.1.2 Fixed Communication

Fixed communication is used to exchange information between ATC centres and between national, sub-regional or regional organisations, i.e. ground-ground fixed communication.

Today analogue voice telephony services are mainly used for ATS (Air Traffic Service) applications. Due to increasing data volumes and level of automation, e.g. to support electronic co-ordination, data network services will become predominant. It is expected that by 2020 ground installations will be connected using a fixed ground-ground IP (Internet Protocol) based network. This is very efficient because both data and voice (Voice over IP –VoIP) can be transmitted on the same network.

The Pan-European Fixed Network Service is foreseen as the long-term strategic ground telecommunications infrastructure for voice and data transmission and switching for the aeronautical community, providing the core supporting infrastructure for SWIM. It will be a procured IP network service supporting new data and legacy applications using IPv6 and IPv4 protocols.

In terms of information distribution services, the AFTN (Aeronautical Fixed Telecommunication Network) has been the primary aeronautical message interchange technology for the last 30 years. The Aeronautical Message Handling Service (AMHS) has now been specified by ICAO for future message handling applications. AHMS is a standard for aeronautical ground-ground communications (e.g. for the transmission of NOTAM, Flight Plans or Meteorological Data) based on X.400 profiles. ANSPs are already deploying AMHS technology for international messaging applications to replace the current AFTN. AMHS is being deployed over TCP/IP in the European region. The first AMHS system went into operational use in 1996 with 36 centres for the German Military and the first AMHS connection in Europe is in operational use since February 2005 between the Air Navigation Service Providers of Germany and Spain.

2.3.1.3 The 2020 Communication Baseline

In summary according to SESAR D3, these are the technologies which need to be fully operational by 2020 to meet the ATM Target Concept. The corresponding deployment schedule will be defined within the various implementation packages in SESAR D4.

• Ground-Ground o IP based ground-ground communications network supporting all the ATM

applications and SWIM services, together with VoIP for ground segments, including VoIP for the ground segment of the air-ground voice link.



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• Voice o 8.33KHz is the standard for voice communications. o SATCOM (Satellite Voice and Data Communications) voice for oceanic and remote

areas.

• Air-Ground Datalink o VDL2/ATN

• Airport o A new Airport data-link to support surface communication, using a derivation of the

IEEE 802.16.

2.3.2 Navigation

The objective of navigation technologies is to provide aircraft positioning and trajectory management in all phases of flight.

En-route Navigation is currently provided by a large range of navigation services using conventional terrestrial systems and more recently global navigation satellite systems (GNSS). A large range of airborne navigation capability also exists, i.e. inertial systems on board of an aircraft usually based on multi-sensor navigation systems. Once it has been initialized with its position and velocity from another source an inertial navigation system is a navigation aid that uses a computer and motion sensors (e.g. accelerometers and gyroscopes) to continuously track the position, orientation, and velocity (direction and speed of movement) of a vehicle without the need for external references.

In accordance with SESAR D3 it is expected that the current ground-based infrastructure will change to a satellite-based one, because of increased navigation performance requirements related to 3D and 4D trajectory management.

According to the performed technology assessment of the SESAR consortium the navigation technologies depicted in Table 2-2 are the initial candidates that meet the high level technical needs for navigation. Dependent on the flight phase (En-route/ terminal navigation, approach & landing, airport surface movement) different technologies apply.

The biggest improvement is expected through global navigation satellite systems (GNSS). The GPS (Global Positioning System) of USA is already used, Russia’s GLONASS (GLObal'naya NAvigatsionnaya Sputnikovaya Sistema) will be commercially usable from 2009, and the European Galileo is expected to be in service from 2013. Even China has recognised the commercial potential of GNSS and announced an own system COMPASS.

Thus at the 2015 horizon, the availability of new GNSS constellations (Galileo, GPS L5) and the further development of augmentation means will improve the accuracy, availability and the integrity of the navigation signal thus allowing enhanced positioning services in all phases of flight, including airport surface. Augmentation of a GNSS is a method of improving the navigation system's attributes, such as accuracy, reliability, and availability, through the integration of external information into the calculation process, which can be basically ground based, aircraft based or satellite based augmentation systems (GBAS, ABAS, SBAS).

http://en.wikipedia.org/wiki/Navigation

http://en.wikipedia.org/wiki/Computer

http://en.wikipedia.org/wiki/Velocity







Table 2-2 Navigation technologies according to SESAR D3

GNSS

Terr

estr

ial

Aid

s

On-Board Navigation Means A

irpor

t

FMS

Navigation technologies

Navigation needs G

PS L

1 an

d L5

Gal

ileo

Glo

nass

SBA

S (E

GN

OS-

WA

AS)

GB

AS

DM

E

ILS,

MLS

Iner

tial N

avig

atio

n Sy

stem

s

AB

AS

(RA

IM o

nly)

Bar

omet

ric A

ltim

etry

HU

D, E

VS

Airp

ort s

urfa

ce g

uida

nce

Tech

nolie

s

1. En-Route & TMA: Positioning Horizontal Position Vertical Position Time

2. En-Route & TMA: Trajectory Management 2D-RNAV

2D-RNP 3D Vertical Navigation 4D Time Constrained Navigation

3. Approach & Landing: Navigation & Positioning

Non-precision Approaches

Cat I / Near Cat I Approaches Cat II/ III Approach & Landing Special Approaches (Curved, Steep, Offset)

4. Airport Surface: Navigation & Positioning Airport Surface Positioning

En-route and terminal manoeuvring area (TMA)

However, still an open question is the institutional establishment of commercial arrangements in aviation. Issues like legal liability, certification and service charges have to



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be considered. Today it is neither technically nor operationally possible to state that GNSS will be the only means for positioning and it becomes necessary to assess the safety, security, operational and cost aspects linked to a redundant terrestrial positioning solution. Certain risks are associated with GNSS, e.g. intentionally or accidentally jamming the signal or natural disturbances (solar storm), and in cases of GNSS service loss backup mechanisms are still required. These could be distance measuring equipment (DME) or TACAN (tactical navigation) for military, as most aircraft are already equipped, the crews are trained and the basic ground infrastructure exists. Also the use of ABAS including inertial systems mitigates the consequences of GNSS service loss.

The transition to GNSS based operations bears the chance to decommission conventional navigation aids (VOR, NDB/ ADF) and thus make available valuable radio spectrum. Hence these terrestrial navaids are not listed in Table 2-2 anymore. Decommissioning of these En-Route and TMA terrestrial navaids could be completed in 2025. However this needs to be carefully planned with the users, such as general aviation (GAT) and military, because this could require a significant rate of equipage of aviation users with dual constellation and possibly dual RNAV equipment to ensure the required performance. Also a backup for GA, where DME installations are not feasible may need to be found. On the other hand, the worldwide network of existing ground based navaids or better their locations today could be used in the future for ground based UAS navaiding.

Approach and landing

Currently the instrument landing system (ILS) is the core landing technology but it is expected to change to GNSS based landings in order to improve airport accessibility in CAT I and CAT II/ III conditions. SBAS, as provided by EGNOS (European Geostationary Navigation Overlay Service) in Europe, is an important enabler and will be used for some categories of users, opening up access to smaller airports. However, full GNSS type landing in the most demanding conditions (CAT II/ III) can only be achieved though the use of GBAS type augmentation. As these systems are designed to enable manned aircraft to operate under conditions that do not allow operations under visual guidance, automatic landing is most of all a feature of unmanned systems at all. These subsystems which are currently in use today are not covered under this section.

Whilst there may thus be a reduced demand for ILS, it should be noted that global usage of ILS means that aircraft will continue to be equipped with this technology for many years. Specifically, ILS CAT I capability has to be maintained in accordance with the equipage fits of military aircraft where the MMR capability will be the basis to support approach and landing until a military Joint Precision Approach and Landing Systems (JPALS) policy is defined. Hence, dependent upon the evolution of GBAS CAT II/ III developments, ILS and MLS decommissioning could spread from 2018 to 2030.

Airport surface movement

GNNS could also improve the navigation and positioning on an airport. Together with a CDTI (cockpit display for traffic information) and a map display including presentation of surrounding traffic this will improve situational awareness and safety, e.g. expected reduced runway and taxiway incursions. For ATC and apron control an A-SMGCS is the means to improve safety, capacity and environmental impact. By providing the pilot with conflict free routing, together with target times, the system will considerably improve







taxiway throughput and reduce taxiway delays and support situation awareness to prevent runway or taxiway incursions.

When providing low visibility access, lighting is the most significant part of the Airport’s infrastructure costs. Airport surface lighting could use the advanced properties of LED technology, such as significantly reduced power consumption and dynamic colour change. Initial deployments could be foreseen within with support to more advanced SMGCS through. For the longer timeframe, detection of the invisible light spectrum properties of LED (such as Infrared), with onboard sensors may provide additional navigation performance, but these need further research.

2.3.2.1 The 2020 Navigation Baseline

In summary the 2020 navigation baseline is depicted as:

• Primary aircraft positioning means will be satellite based for all flight phases.

• Positioning is expected to rely on a minimum of two dual frequency satellite constellations (Galileo, GPS L1/L5 and potentially other constellations, assuming interoperability) and augmentation as required:

o Aircraft based augmentation (ABAS) such as INS and multiple GNSS processing receiver,

o Satellite based augmentation (SBAS) such as EGNOS in Europe and WAAS in USA

• Terrestrial Navigation infrastructure based on DME is maintained to provide a backup for en route and TMA.

• Enhanced on-board trajectory management systems and ATS flight processing systems to support the trajectory concept.

These technologies need to be fully operational by 2020 towards the ATM Target Concept. Their deployment schedule will yet be defined in the various implementation packages of SESAR D4.

2.3.3 Surveillance

As an integral part of Air Traffic Management (ATM), surveillance positional data constitutes the principal means of surveillance of aircraft for the efficient execution of Air Traffic Control. The objective of the surveillance service is to provide a complete picture of the actual traffic situation to ensure a safe separation and an efficient traffic flow. ATM surveillance is the observation of an area or space for the purpose of determining the position and movement of aircraft or vehicles in that area or space to enable Air Traffic Control. Currently in most areas of Europe surveillance is relying on radar coverage based Secondary Surveillance radar (SSR) and complemented by Primary Surveillance Radar (PSR).



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Table 2-3 depicts the surveillance technology foreseen in SESAR. Three basic surveillance principles are distinguished: independent non-cooperative, independent cooperative and dependent cooperative surveillance.

Independent non-cooperative surveillance determines the position (2-D) without reliance on aircraft avionics. It is based on primary surveillance radar (PSR) and by such is independent on any form of airborne avionics. PSR provides an independent surveillance means to detect non-co-operative targets or to provide a safety-net in the event of a co-operative systems failure. The PSR calculates the position of targets based on time delay between transmission and receipt of radar pulses. This basic technology will continue to exist, as necessary, for safety and security reasons, e.g. to identify transponder failures or unidentified vehicles. It is expected that by 2020 new cheaper forms of PSR using multi static techniques (MSPSR) are available.

Independent cooperative surveillance utilises the aircraft transponder to derive position and other avionic data. This is seen as the principal means of surveillance in 2020. It is based on (monopulse) secondary surveillance radar (SSR), SSR Mode S, multi lateration (MLAT) or WAM (wide area multi lateration). The latter uses ground based antennas instead of rotating equipment and thus is less cost intensive. Multi lateration, also known as hyperbolic positioning, is the process of locating an object by accurately computing the time difference of arrival of an signal emitted by the object to three or more receivers.

SSR is a co-operative surveillance system requiring an aircraft to carry appropriate transponders. The SSR calculates the position of targets based on time delay between transmission and receipt of radar pulses. The technique permits the extraction of Mode A code and Mode C (altitude) information. In core Europe, Mode S SSR is the preferred architecture for 2011+, however it is recognised that conventional SSR is still required in some regions of Europe. Mode S SSR is a co-operative surveillance and communication system for ATC. It employs ground-based interrogators and airborne transponders. A principal feature of Mode S that differs from existing monopulse Secondary Surveillance Radar is that each aircraft is assigned a unique 24-bit Aircraft Address. Using this unique address, interrogations can be directed selectively to a particular aircraft and replies unambiguously identified.

Dependent cooperative surveillance is dependent on aircraft systems and utilises the aircraft derived position and avionic data like identification and altitude among other parameters to broadcast “air-to-ground” and “air-to-air” transmission. This technology is a solution for low-density non-radar airspace or as a complement to independent surveillance in medium to high-density airspace.







Table 2-3 Surveillance technologies according to SESAR D3

Inde

pend

ent

Non

-co

oper

ativ

e

Inde

pend

ent

Coo

pera

tive

Dep

ende

nt

Coo

pera

tive

Surveillance technologies

Surveillance needs PS

R (p

rimar

y su

rvei

llanc

e ra

dar)

SMR

(sur

face

mov

emen

t rad

ar)

Mul

ti St

atic

PSR

SSR

(sec

onda

ry s

urve

illan

ce ra

dar)

WA

M (w

ide

area

mul

ti la

tera

tion)

Airp

ort M

ulti

late

ratio

n (M

LAT)

AD

S-B

TIS-

B

1. ATC Surveillance ATC surveillance means En-route/ TMA ATC surveillance means approach & landing ATC surveillance means airport surface A-SMGCS (ATC surveillance functions)

2. Airborne Surveillance Airborne surveillance ATSAW Airborne surveillance ASAS spacing Airborne surveillance ASAS separation Airborne surveillance ASAS self separation

Surveillance is foreseen to remain a mix of PSR (including MSPSR) for safety, SSR Mode S and WAM as independent surveillance and ADS-B Out for dependent surveillance. Service providers will have a flexible choice of technologies depending on the respective operational requirements, geographic location and cost efficiency decisions.

A progressive introduction of newer, more cost effective, types of non-cooperative surveillance technologies is expected to replace the older PSR technology. Newer challenges of UASs, composite aircraft types and wind farms will also need to be accommodated by these newer technologies as wooden aircraft with a very low Radar cross section (RCS).



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Most States are currently upgrading their Monopulse SSRs to SSR Mode S. Thus, they will not need replacing until about 2020. WAM systems are already being implemented to provide SSR type coverage in locations where, for example, conventional SSR may be unsuitable. Gradually ADS-B Out certified systems will start to become available and this will be the turning point for a change in direction for ground-based surveillance.

In order to provide ASAS (Airborne Separation Assistance System) functionalities data between aircraft has to be exchanged (air-to-air surveillance). Airborne Separation Assistance System (ASAS) is officially defined (ICAO ASAS Circular) as: “An aircraft system based on airborne surveillance that provides assistance to the flight crew supporting the separation of their aircraft from other aircraft”. ASAS has significant potential for the future aviation environment and transfer of separation responsibility is a significant change from today’s operations but it is an important step towards fully autonomous operations. In order to implement ASAS, a source of surveillance information is necessary to enable an airborne traffic situation picture to be developed.

ADS-B (Automatic Dependent Surveillance Broadcast) with in/out capabilities is a promising candidate and is viewed as the key enabler for providing this picture. ADS-B is defined by ICAO as: “ADS-B is a surveillance application transmitting parameters, such as position, track and ground speed, via a broadcast mode data link, and at specified intervals, for utilisation by any air and/or ground users requiring it.”

ADS-B relies on the regular and frequent transmission of position reports via a broadcast data link. The position reports are sent periodically by the aircraft with no intervention from the ground function. Position reports may be received by any recipient in range of the transmitting aircraft. Recipients may be communications receivers (‘data acquisition units’) on other aircraft, ground vehicles or at fixed ground sites. If received by a data acquisition unit, the position report will be processed with other surveillance data and may be forwarded to a controller/pilot display.

ADS-B offers data delivery from aircraft-to-aircraft or from aircraft-to-ground. Transmitting data directly from air-to-air means that there is no need for a ground infrastructure to be present for airborne surveillance to be performed. One of the main benefits of air-to-air operations of ADS-B is that it enables airborne situational awareness. By using position reports received from surrounding aircraft, a traffic surveillance picture can be generated in the cockpit of all aircraft. This means that an aircraft can be presented with a surveillance picture of surrounding traffic on a cockpit display, by using ADS-B data transmitted by other aircraft.

ADS-B in Europe is based on datalink technology 1090 MHZ extended squitter (1090ES). It should be noted that there are two other datalinks used for ADS-B in some localised areas of the world, Universal Access Transmitter (UAT) operating at a frequency of 978 MHz, and VHF Datalink Mode 4 (VDLM4) which operates within the VHF air band. A datalink describes the data protocol used to broadcast the ADS-B messages. Both the transmitting and receiving aircraft have to operate on the same datalink to allow the exchange of information.

ES1090 for all has technical limitations, e.g. reliability, response time, saturation and power consumption. For integrity, capacity and safety requirements for advanced separation and self-separation applications, it is foreseen that a new or complementary ADS-B technology







is necessary. Considering spectrum issues, it is proposed that such as system will operate in the L band (1-2 GHz).

A key driver of the ADS-B progress in Europe is the CRISTAL (Co-opeRative ValidatIon of Surveillance Techniques and AppLications of ADS-B) initiative of the CASCADE Programme (Co-operative ATS through Surveillance and Communication Applications Deployed in ECAC) by EUROCONTROL. This CRISTAL initiative consists of validation trials, as a means of testing the technology in real situations, with partnerships between local ANSP, airlines and industry, to check operational, safety and performance requirements. By this the CRISTAL projects will provide inputs to the standardisation, certification and operational approval.

The CASCADE programme co-ordinates the European implementation of ADS-B, a surveillance technique that relies on aircraft broadcasting their identity, position and other aircraft information. This signal can be captured on the ground for surveillance purposes (ADS-B-out) or on board other aircraft for air traffic situational awareness (ADS-B-in) and airborne separation assistance. ADS-B-out is expected to reach initial operational capability status in 2008, ADS-B-in for air traffic situational awareness in 2011. In order to meet the surveillance requirements of different environments, ADS-B-out can be used as a sole means of surveillance or in combination with radar or multi-lateration.

ADS-B-out has safety and capacity benefits in areas where there is no surveillance today or where the separation minima applied is large due to surveillance deficiencies. It has also significant economic benefits when used to replace part of a radar infrastructure.

ADS-B-in has primarily safety benefits by increasing the situational awareness of pilots, but it also enables to provide capacity benefits when spacing and separation applications will be introduced.

ADS-B can also be used for tracking mobiles (ground vehicles and aircraft on the surface) as part of ATC surveillance at the airport. It thus can be an element of a A-SMGCS (Advanced-Surface Movement Guidance and Control) system.

The main benefits of ADS-B are:

• the reduced cost when compared to other surveillance alternatives (up to 1/10 of a radar system with system coverage),

• more accurate surveillance information available to the ground systems, • the availability of surveillance data where there was none before, i.e. where there was

no surveillance service, • additional data that is available with ADS compared to traditional SSR. Examples of this

additional data are flight path intent, i.e. the aircraft’s route programmed into the on-board flight management computer and wind measurements taken from the aircraft (it must be noted that the additional data may be available through other sources, for example Mode S Enhanced Surveillance), and

• the support of airborne surveillance applications which will enable many future safety and capacity benefits. The new ASAS functions may allow controllers to delegate some tasks to the aircrew, which would reduce the controller’s workload.



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For aircraft not equipped with ADS-B-out the TIS-B (Traffic Information Service – Broadcast) technology could be used. TIS-B supplements ADS-B air-to-air services to provide complete situational awareness in the cockpit of all traffic known to the ATC system.

TIS-B is an important service for an ADS-B link in airspace where not all aircraft are transmitting ADS-B information. The ground ADS-B station transmits surveillance target information on the ADS-B data link for unequipped aircraft or aircraft transmitting only on another ADS-B link.

Traffic Information Services Broadcast (TIS-B) makes use of the best available ground surveillance source (e.g. PSR, SSR, ADS-B), i.e.

• ground radars for primary and secondary targets, • multi-lateration systems for targets on the airport surface, • ADS-B systems for targets equipped with a different ADS-B link,

which are processed to track the position of aircraft (see Figure 2-2). Because the ADS-B link can be used to provide other broadcast services such TIS-B, “ADS-B like” messages are then generated and broadcast by a TIS-B ground station on the 1090 MHz frequency. Aircraft equipped with a 1090 MHz receiver can receive TIS-B messages for display on a CDTI. While 1090 MHz ADS-B receivers are now being developed, it is expected that these receivers will also be capable of receiving TIS-B messages.

TIS-B allows any aircraft equipped with a conventional transponder to be made visible on a cockpit display in another aircraft. The important point, however, is that the tracked aircraft needs to be in coverage of a surveillance system, while the receiving aircraft has to be within the broadcast region of the TIS-B ground station. It would not be possible in oceanic or remote areas where there is no SSR or PSR coverage.

TIS-B is intended to provide CDTI capability in an environment where not all aircraft are equipped with ADS-B. TIS-B is closely linked to ADS-B because it could help the transition to air-to-air surveillance. It is promoted as a technology to be used in the transition from the current situation to one where high levels of ADS-B equipage exist. With TIS-B, a partial equipage of ADS-B on some aircraft can be supplemented by surveillance information from the ground. Hence, complete (100%) equipage is not required to provide full cockpit surveillance.

TIS-B is at a trial stage. It has been demonstrated in some projects, but standardisation is incomplete and the details of an operational service using TIS-B are not resolved.

Some arguments against TIS-B exist. If ADS-B and TIS-B equipment are not interoperable then those aircraft or airlines which invested in the ADS-B in/out technology would need to invest also in TIS-B to cover the fact that the other airspace user has not invested in ADS-B to achieve air-to-air surveillance. Then there is scepticism about the necessary performance, namely update rate and latency. Thus TIS-B could be a transitional step, limited to basic ATSAW (Air Traffic Situational Awareness) application.






Figure 2-2 Schematic TIS-B network

Another system of dependent cooperative surveillance especially of interest for UAS operating in uncontrolled airspace or under VFR is realised with the FLARM system. Many surveillance technologies are designed to fulfil the commercial aviation's needs. The light aviation is lacking a low-cost low-power small-sized system capable of warning the pilot early enough, supporting him to avoid collisions.

FLARM is an affordable collision-warning system for general aviation and recreational flying. It is based on GPS and radio and has been developed by glider pilots for glider pilots. It broadcasts the glider's position using a radio data link. If other gliders equipped with a compatible system fly nearby, the devices assess future conflicts and warn the pilot accordingly by acoustical and optical means. In addition, FLARM warns whenever you approach a fixed obstacle like a cable or an antenna.

Since 2004, over 9,000 FLARM compatible devices have been installed in aircraft worldwide. The devices have been credited on many occasions with avoiding dangerous situations and increasing situation awareness. The small-size, low-cost, low-power device FLARM broadcasts its own position and speed vector (as obtained with an integrated GPS) over a license-free ISM band radio transmission. At the same time it listens to other devices based on the same standard. Intelligent motion prediction algorithms predict short-term conflicts and warn the pilot accordingly by acoustical and visual means. FLARM incorporates a high-precision WAAS 16-channel GPS receiver and an integrated low-power radio transceiver. Static obstacles are included in FLARM's database. The collision warning algorithms were calibrated and optimized using thousands of flight logs. No warning is given if an aircraft does not pose an immediate threat. It’s features are:




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• Early warning if other aircraft equipped with FLARM approach on a collision course. • warns when approaching static obstacles, which requires an obstacle database

installed • uses license free SRD band for transmission • simple installation - 12V, 52mA • intelligent motion prediction minimizes "nuisance" alarms

However there are certain risks associated with FLARM. Devices like that do not profit from a broad base of technical or operational experience made as these devices never existed before. There are many open risk issues, namely the legality of the digital radio, potential infringements with intellectual property and a potentially limited diffusion of such devices represent specific risks. Finally the frequency band on which FLARM is broadcasting is not protected and used by many other applications (ISM band – Industrial, Scientific and Medical band). It is thus prone to frequency jamming.

2.3.3.1 The 2020 Surveillance Baseline

In summary the 2020 surveillance baseline is described as follows:

• For the airspace, cooperative surveillance will be the norm, complemented as required by Independent non-cooperative surveillance to satisfy safety and security requirements. For the airport both cooperative and independent non-cooperative surveillance systems will be necessary.

o Primary surveillance radar (PSR) will provide independent non-cooperative surveillance.

o Since aircraft will have the necessary mode S and ADS-B equipage, the choice of cooperative surveillance technology (Mode S, ADS-B, MLAT) remains flexible, with the service provider determining the best solution for their particular operating environment, based on cost and performance.

o Surface movement radar (SMR) will provide the independent non-cooperative airport surveillance.

• ADS-B IN/OUT is provided by 1090 ES.

• With a mandate of ADS-B ES 1090 out, TIS-B will not be needed in the transition to support ASAS applications.

• Satellite based ADS-C (ADS-Contract) for oceanic and remote areas (Note: The basic concept of this ADS application is that the ground system will set up a contract with the aircraft such that the aircraft will automatically provide information obtained from its own on-board sensors, and pass this information to the ground system).

Beyond 2020 the SESAR consortium is expecting that PSR is replaced by less costly independent non-cooperative surveillance technology, and that the 1090 ES system supporting ADS-B in/out is improved and complemented with an additional high performance datalink.







2.3.4 Risk and Recommendations

The above proposed CNS technologies for 2020 and beyond stem from a technology assessment process performed by the SESAR consortium to define a strategy and propose a roadmap with achievable transition steps. Technical needs had to be derived from ConOps and foreseen ATM architecture requirements. Technical enablers were identified that potentially address these needs. The identified technologies were assessed if they fulfil critical design features (e.g. availability, integrity, performance, security, continuity) and considering the deployment issues and steps to operational use (maturity, costs, standards). Pros and cons had to be considered and gaps and overlap had to be identified. All this resulted in key issues and recommendations for the necessary development of the proposed technology as well as certification and standardisation activities to prepare the 2020 timeframe.

The following key issues were identified, which describe risk and opportunities to the timely deployment of the proposed technologies.

Deployment schedule: The introduction of new CNS technology is a time-consuming process, mainly caused by necessary certification and standardisation additional to research, development and validation. This may take easily 15 years or more. However to achieve the SESAR objectives a time frame of 7 to 10 years will be required. Thus all stakeholders must concentrate their activities and efforts.

ATM technology characteristics: The aviation environment is very unique with high standards on safety and security. Technology from other sectors outside aviation cannot directly be applied in the ATM system. It requires considerable adaptation of such technology to meet the ATM performance requirements.

Interoperability: Global, worldwide interoperability is a key issue in respect of CNS technologies. Airspace users expect to be able to exploit their aircraft equipment in multiple regions. Thus considerable effort is needed to ensure coordination with other regions, with the goal to obtain recognised ICAO standards. Joint ongoing activities to evaluate and select new technologies and technical enablers based on performance requirements must be further encouraged and reinforced. Civil-military interoperability requirements will also have to be considered to enable the maximum re-use of available military capabilities.

Radio spectrum and bandwidth constraints: With increasing CNS applications requiring a high level of data exchange via datalink, the availability of sufficient radio frequency is a major concern. The radio spectrum, especially the frequencies which enable data transmission at high rates, is a limited resource, but of increasing commercial interest by various sectors (e.g. mobile communication). The aviation community is forced to represent their position at the International Telecommunication Union (ITU), an UNO institution, at the World Radio communication Conference (WRC), and on the European level. Those treaties, laws, and regulations have divided the spectrum by type of service use, (e.g., radio navigation, aeronautical mobile, fixed-satellite, and mobile satellite), by user (e.g., Government and non-government), and by region (1) Europe, Africa, Former Soviet Union, and Near East; (2) Western Hemisphere; and (3) Far East and Western Pacific.



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2.4 ATM Operations - objectives and means

To accommodate the anticipated growth of the air transport industry, the ATM system is required to increase its capacity whilst maintaining adequate levels of safety. In addition, aircraft operators are requesting additional flexibility to accommodate their preferences, so that they can better pursue their respective business objectives. Furthermore, there is an increasing pressure on the system to facilitate the reduction of the environmental impact of aircraft operations.

Under this premise, the SESAR program is the European Air Traffic Management (ATM) modernisation program. The aim is to merge technological, economic and regulatory aspects making use of the Single European Sky (SES) legislation. The idea is to coordinate the plans and actions of the different stakeholders and federate resources for the development and implementation of the required improvements throughout Europe, in both airborne and ground systems.

Concerning the future ATM system, SESAR document [SESAR Definition Phase, Task 2.2.2 - Milestone 3 DLT-0162-222-02-00] reports:

"The European ATM Network of the future will be structured around the use of a performance-based, service-oriented operational concept. Central to the Network will be a single European ATM System which will provide a variety of ATM services to all types of airspace user to meet their respective needs ..... SESAR proposes a service oriented relationship between airspace users, airport operators and ATM service providers."

The following two points are the core of the SESAR concept of operation:

• trajectory-based operations respecting the business case of each single user • improved conflict management through i) a shifting from tactical interventions to

strategic deconfliction, ii) optimal distribution of the task between all the ATM partners iii) improve the automation support

2.4.1 Airspace organisation and management 2.4.1.1 Current Situation

Airspace today is not a unique thing, but a combination of different airspaces with specific rules and requirements. The flight rules can be either Visual Flight Rules (VFR) or Instrument Flight Rules (IFR).

VFR are a set of aviation regulations under which a pilot may operate an aircraft in weather conditions sufficient to allow the pilot, by visual reference to the environment outside the cockpit (horizon, ground observation), to control the aircraft's attitude, navigate, and maintain safe separation from obstacles such as terrain, buildings, and other aircraft, generally without the need for monitoring by air navigation authorities. The essential collision safety principle guiding the VFR pilot is "see and avoid."

VFR flights require favourable weather conditions, i.e. specified visibility conditions and distance from clouds have to be maintained. Meteorological conditions that meet the minimum requirements for VFR flight are termed visual meteorological conditions (VMC). If they are not met, the conditions are considered instrument meteorological conditions (IMC),







and a flight may only operate under IFR or will not start if not having IFR equipment installed.

IFR are a set of regulations and procedures for flying aircraft whereby navigation and obstacle clearance is maintained with reference to aircraft instruments only and separation from other aircraft is provided by Air Traffic Control. IFR flights require that the aircraft is equipped with suitable instruments and with navigation equipment, because there are no visibility requirements as under VFR. The exact minimum equipment for VFR and IFR will be defined by national laws.

Airspace is classified based on the services provided within it (this being dependent on flight regime) and on the minimum meteorological conditions needed for visual flights. In Table 2-4 the airspace classification according to ICAO is depicted, including the responsibilities for separation, air traffic service provided, whether an ATC clearance is required, etc. Airspace is classified on a scale from A to G, A being the most restricted (and safest) and G being the freest.

Airspace is divided into two basic types:

Controlled airspace exists where it is deemed necessary that air traffic control has some form of positive executive control over aircraft flying in that airspace. Generally controlled airspace is divided vertically in lower airspace controlled by Area Control Centres (ACC) and upper airspace, controlled by Upper Area Control Centres (UAC). The lower airspace is then divided horizontally into Flight Information Regions (FIR) and the upper airspace into Upper Flight Information Region (UIR). Each of these information regions are then further divided into control sectors.

Uncontrolled airspace is airspace in which air traffic control does not exert any executive authority, although it may act in an advisory manner.



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Table 2-4 ICAO airspace classification

Class Type of flight

Separation provided

Service provided Speed limitation

Radio comm. required

Subject to an ATC clearance

A IFR IFR B VFR

All aircraft

IFR IFR from IFR IFR from VFR

Air traffic control service

Not applicable

C

VFR VFR from IFR 1) ATC service for separation from IFR; 2) VFR/VFR traffic information (+ traffic avoidance on request)

IFR IFR from IFR ATC service, traffic information about VFR flights (+ traffic avoidance advice on request)

D

VFR Nil IFR/VFR and VFR/VFR traffic information (+ traffic avoidance advice on request)

IFR IFR from IFR ATC service and, as far as practical, traffic information about VFR flights

Continuously two-way

yes

E

VFR Nil Traffic information as far as practical

No

IFR IFR from IFR as far as practical

Air traffic advisory service; flight information service

Continuously two-way

F

VFR Nil No IFR Nil Continuously

two-way G

VFR Nil

Flight information

250 kts IAS below 3050 m (10.000 ft) AMSL

No

No

The ICAO classification gives no clear advises where each airspace category shall be located in space. This is subject to national regulations, which may differ significantly. The choice which airspace category is used lies with the regulatory institutions in the states. The choice depends on the requirements of the airspace users and the ANSPs. As such the vertical and lateral limits of each airspace category might be different. As an example, the following Figure 2-3 will illustrate the structure of the German airspace. Airspace A and B are not existing in Germany. In Figure 2-4 two examples from the French airspace are given, the airspace around Paris and around Toulouse. Most of the French airspace around airports is similar to the Toulouse airspace, with class D areas protecting the airports. The Paris area is very specific, with a class A area protecting the large international airports. When far from airports (outside CTR and TMA) the airspace is mainly composed of class G areas.

Title: D1.1 Definition of the Environment for Civil UAS Applications Date: 15/02/2008 Document ID: INOUI_WP1.1_DFS_D1.1_CO_v1.0




This project has been carried out under a contract awarded by the European Commission. No part of this report may be used, reproduced and/or disclosed in any form or by any means without the prior written permission of the INOUI project

partners. © 2007 – All rights reserved

Figure 2-3 Airspace structure and visual flight rules in Germany






This project has been carried out under a contract awarded by the European Commission. No part of this report may be used, reproduced and/or disclosed

Finally an overview of the airspace structure and classification in Europe (ECAC states) is depicted in Figure 2-5 to illustrate the existing variety how national airspace is organised by each state according to their national requirements. Controlled and uncontrolled airspace is further divided into control zones (CTR) around (major) airports and terminal manoeuvring areas (TMA) for arrival and departure traffic.

Figure 2-4 French airspace around Paris and Toulouse

In preparation of the Single European Sky (SES) in May 2006 the European Commission enacted regulation No 730/2006 on airspace classification and access of flights operated under visual flight rules above flight level 195 (19500 feet). This Regulation introduces classification and common rules for all airspace above 19500 feet. It sets out a more transparent framework for cross-border flights as well as ensuring easier access for "VFR" flights (flights operated under visual flight rules). These rules shall make it easier for foreign pilots to understand the airspace system. Thus the Commission, following a proposal by the European Organisation for the Safety of Air Navigation (EUROCONTROL), has defined airspace above flight level 195 as being class C.

in any form or by any means without the prior written permission of the INOUI project partners. © 2007 – All rights reserved






Figure 2-5 Airspace Classification ECAC States 2007 (Eurocontrol 2007)

2.4.1.2 Airspace related Air Traffic Services (ATS)

It is not sufficient to know the airspace flight rule, including see and avoid rules for VFR traffic, the required speed limit, the need for radio communication and the need for ATC








clearance as depicted in Table 2-4 above. Especially for UASs, there are other matters to be taken into account. It is essential to know which air traffic services are provided and if traffic is separated by Air Traffic Control (ATC). The major Air Traffic Services with relevance for the operation of UAS are Air Traffic Control (ATC), Flight Information Service (FIS) and Aeronautical Information Service (AIS).

ATC provides its service in controlled airspace and is responsible for the: • Separation between aircraft and between aircraft and obstacles. • Maintaining an orderly flow of air traffic. • Provision of advice and information for a safe and efficient conduct of flights.

This air traffic service within the ATM operations (see logical architecture in Figure 2-1) is divided into Aerodrome, Approach and Area control.

Aerodrome control is responsible for the control of aircraft at the aerodrome, consisting of stands, taxiways and runways, and control of aircraft in the airspace directly surrounding the aerodrome and have interfaces to APP units. The control of the aircraft is mainly based upon visual reference but is supported by surveillance infrastructure, e.g. ground radar.

Approach control is responsible for control of the air traffic in the terminal airspace surrounding an airport/ aerodrome including arriving and departing aircraft.

En-route ATC is responsible for the provision of air traffic control to aircraft after departure and before arrival, i.e. those aircraft which are not controlled by approach ATC or aerodrome ATC.

FIS is a basic form of Air Traffic Control service which is available to any aircraft within a Flight Information Region (FIR), as agreed internationally by ICAO. It is defined as information pertinent to the safe and efficient conduct of flight, and includes information on other potentially conflicting traffic, possibly derived from radar. Contrary to ATC, FIS does not provide positive separation from that traffic, but gives “traffic advise”.

Flight Information also includes: • Meteorological information • Information on aerodromes • Information on possible hazards to flight

The purpose of the AIS (Aeronautical Information Service) is to ensure the flow of information necessary for the safety, regularity and efficiency of international air navigation. The provision of aeronautical information/data that is required for operational use by international civil aviation includes the Aeronautical Information Publication (AIP), NOTAM (NOtice To Airmen), Pre-Flight Information Bulletins (PIB), and Aeronautical Information Circulars (AIC). Each element is used to distribute specific types of aeronautical information.

Also the filing of flight plans is in the responsibility of AIS.

The AIP is a publication issued by or with the authority of a state and containing aeronautical information of a lasting character essential to air navigation. It is designed to be a manual containing thorough details of regulations, procedures and other information







pertinent to flying aircraft in the particular country to which it relates. It is usually issued by or on behalf of the respective civil aviation administration. AIPs normally have three parts - GEN (general), ENR (en route) and AD (aerodromes). The document contains many charts; most of these are in the AD section where details and charts of all public aerodromes are published.

NOTAMs are filed with an aviation authority to alert aircraft pilots of any hazards en route or at a specific location. The authority in turn provides means of disseminating relevant NOTAMs to pilots, typically exchanged over AFTN circuits. NOTAMs are issued (and reported) for a number of reasons, such as:

• hazards such as air-shows and parachute jumps • flights by important people such as heads of state • closed runways • inoperable radio navigational aids • military exercises with resulting airspace restrictions • inoperable lights on tall obstructions • temporary erection of obstacles near airfields (e.g. cranes) • passage of flocks of birds through airspace (a NOTAM in this category is known as

a BIRDTAM) • software code risk announcements with associated patches to reduce specific

vulnerabilities

The following table show the possible Air Traffic Service in relation to the airspace, including possible separation and the flight rules.

http://en.wikipedia.org/wiki/Aviator







Table 2-5 Airspace and ATS

Airspace classification

Type of airspace Flight rules Possible ATS Separation by ATC

A IFR only ATC All aircraft B IFR, VFR ATC All aircraft

IFR ATC IFR/IFR, IFR/VFR C VFR ATC,

FIS, (VFR/VFR) VFR/VFR

CTR “C” Same regulations as for airspace C IFR ATC, FIS about

VFR traffic IFR/IFR

D VFR FIS about IFR traffic

No separation

CTR “D” Same regulation as for airspace D IFR ATC, FIS about

known VFR flights

IFR/IFR

E

Controlled Airspace

VFR FIS if possible No separation IFR In Flight AIS if

possible IFR/IFR as

known F VFR FIS No separation IFR1

FIS No separation G

Uncontrolled Airspace

VFR FIS No separation

Even separation by ATC will not prevent a possible near miss or mid air collision, it will ease the situation for the operation of a UAV.

If VFR is the desired flight rule, it must be clear, that active separation by the aircraft itself is mandatory. Therefore, the required “see (better sense) and avoid capability” must include any means to actively detect wooden aircraft, parachutes, balloons etc. and to react with standard procedures.

FIS can only be given for known traffic from ATS.

A summary of the airspace related requirements for a UAV is listed below:

• Depending on the operational needs, a safe communication link between ATC and control station

• Depending on operational needs, a safe command and control link between Aircraft and control station

• Depending on the airspace and national law, a defined minimum equipment • The ability to maintain or change a (given) flight path. • The ability to maintain or change a (given) altitude • The ability to maintain or change a (given) airspeed ( horizontal and vertical)

1 In some countries (Germany, Austria, Hungary) IFR is not allowed in airspace G.







• The ability to perform standard procedures ( to know them and to fly them correctly) • The ability to identify or change the current position • The ability to communicate with ATC and sometimes other aircraft • The ability to detect other objects (sense and avoid) • The ability to react autonomously, or remotely controlled by the GCS

Eurocontrol has defined high-level, generic specifications how to operate UAS outside segregated airspace [5]. Though the focus is on military UAS, presumably due to the dominant role of military applications in current days and the operational requirements to fly outside segregated airspace, these specifications are of relevance for civil UAS as well.

These specifications require that UAS operations should not increase the risk to other airspace users; that ATM procedures should mirror those applicable to manned aircraft; and that the provision of air traffic services to UAS should be transparent to ATC controllers. Moreover, they are not constrained by limitations in current UAS capability. The summary of these specifications is listed in the following Table 2-6.

Table 2-6 Eurocontrol specifications for the use of military UAV as operational air traffic outside segregated airspace [5]

UAV 001 For ATM purposes, where it becomes necessary to categorize UAV operations, this should be done on the basis of flight rules, namely IFR or VFR as applied to OAT.

UAV 002 For ATM purposes, the primary mode of operation of a UAV should entail oversight by the pilot-in command, who should at all times be able to intervene in the management of the flight. A back-up mode of operation should enable the UAV to revert to autonomous flight in the event of total loss of control data-link between the pilot-in-command and the UAV. This back-up mode of operation should ensure the safety of other airspace users.

UAV 003 UAVs should comply with VFR and IFR as they affect manned aircraft flying OAT. For VFR flight, the UAV pilot-in-command should have the ability to assess in-flight meteorological conditions.

UAV 004 UAVs should comply with the right-of-way rules as they apply to other airspace users.

UAV 005 For IFR OAT flight by UAVs in controlled airspace, the primary means of achieving separation from other airspace users should be by compliance with ATC instructions. However, additional provision should be made for collision avoidance against unknown aircraft.

UAV 006 For VFR OAT flight by UAVs, the UAV pilot-in command should utilize available surveillance information to assist with separation provision and collision avoidance. In addition, technical assistance should be available to the pilot-in-command to enable him to maintain VMC and to detect and avoid conflicting traffic. An automatic system should provide collision avoidance in the event of failure of separation provision.







UAV 007 A UAV S&A system should enable a UAV pilot-in-command to perform those separation provision and collision avoidance functions normally undertaken by a pilot in a manned aircraft, and it should perform a collision avoidance function autonomously if separation provision has failed for whatever reason. The S&A system should achieve an equivalent level of safety to a manned aircraft.

UAV 008 A UAV S&A system should notify the UAV pilot-in command when another aircraft in flight is projected to pass within a specified minimum distance. Moreover, it should do so in sufficient time for the UAV pilot-in command to manoeuvre the UAV to avoid the conflicting traffic by at least that distance or, exceptionally, for the onboard system to manoeuvre the UAV autonomously to miss the conflicting traffic.

UAV 009 Implementation of separation provision and collision avoidance functions in an S&A system should as far as is reasonably practicable be independent of each other. In execution, they should avoid compromising each other.

UAV 010 Within controlled airspace where separation is provided by ATC, the separation minima between UAVs operating IFR and other traffic in receipt of a separation service should be the same as for manned aircraft flying OAT in the same class of airspace2.

UAV 011 Where a UAV pilot-in-command is responsible for separation, he should, except for aerodrome operations, maintain a minimum distance of 0.5nm horizontally or 500ft vertically between his UAV and other airspace users, regardless of how the conflicting traffic was detected and irrespective of whether or not he was prompted by a S&A system.

UAV 012 Where a UAV system initiates collision avoidance autonomously, it should achieve miss distances similar to those designed into ACAS. The system should be compatible with ACAS.

UAV 013 UAV operations at aerodromes should interface with the aerodrome control service as near as possible in the same way as manned aircraft.

UAV 014 When taxiing, and in the absence of adequate technical assistance, a UAV should be monitored by ground-based observers, who should be in communication with the aerodrome control service and with the UAV pilot-in-command.

UAV 015 For take-off and landing and flight in an aerodrome visual circuit, the UAV pilot-in-command should be able to maintain situational awareness to fulfil his responsibility for collision avoidance, and he should comply with aerodrome control service instructions.

2 The Australian CASA doubles the separation minima as for AC with radio communication failure (Transponder code 7700).







UAV 016 Where safe integration is impracticable, consideration should be given to excluding other aircraft from the airspace in the immediate vicinity of an aerodrome during the launch and recovery of UAVs.

UAV 017 UAV emergency procedures should mirror those for manned aircraft as far as practicable. Where different, they should be designed to ensure the safety of other airspace users and people on the ground, and they should be coordinated with ATC as appropriate.

UAV 018 UAVs should be pre-programmed with an appropriate contingency plan in the event that the pilot-in-command is no longer in control of the UAV.

UAV 019 A UAV System should provide a prompt indication to its pilot-in-command in the event of loss of control data-link.

UAV 020 When a UAV is not operating under the control of its pilot-in-command, the latter should inform the relevant ATC authority as soon as possible, including details of the contingency plan which the UAV will be executing. In addition, the UAV System should indicate such loss of control to ATC.

UAV 021 Where a UAV system cannot meet the technical and/or functional requirements for operation as OAT, that portion of the sortie should be accommodated within temporary reserved airspace to provide segregation from other airspace users.

UAV 022 While in receipt of an air traffic service, the UAV pilot-in command should maintain 2-way communications with ATC, using standard phraseology when communicating via RTF. The word ‘unmanned’ should be included on first contact with an ATC unit.

UAV 023 The air traffic service provided to UAVs should accord with that provided to manned aircraft.

UAV 024 Where flight by manned aircraft requires the submission of a flight plan to ATC, the same should apply to flight by UAVs. The UAV flight plan should indicate that it relates to an unmanned aircraft, and should include details of any requirement for en-route holding.

UAV 025 While in receipt of air traffic service, UAVs should be monitored continuously by the UAV pilot-in command for adherence to the approved flight plan.

UAV 026 Pilots-in-command should have detailed knowledge of the performance characteristics of their particular vehicle. ATC controllers should be familiar with UAV performance characteristics insofar as they relate to integration with other traffic under their control.

UAV 027 The weather minima for UAV flight should be determined by the equipment and capabilities of each UAV system, the qualifications of the UAV pilot-in command, the flight rules being flown and the class of airspace in which the flight is conducted.







UAV 028 With regard to cross-border operations, state UAVs should be bound by the same international conventions as manned state aircraft. In addition, flights by state UAVs into the FIR/UIRs of other states should be pre-notified to the relevant FIR/UIR authorities, normally by submission of a flight plan. ATC transfers between adjacent states should accord with those for manned aircraft.

UAV 029 UAVs should carry similar functionality for flight, navigation and communication to that required for manned aircraft. The exemption policy for manned state aircraft with regard to specific equipage requirements should also apply to state UAVs.

UAV 030 The UAV pilot-in-command should be provided with an independent means of communication with ATC in case of loss of normal communications linkage, for example via telephone.

UAV 031 A pilot-in-command should be able to provide a prompt response to separation provision instructions similar to that by a pilot of a manned aircraft.

2.4.1.3 Future Airspace Situation as defined in SESAR

The SESAR document [SESAR Definition Phase, Task 2.2.2 - Milestone 3 DLT-0162-222-02-00] states:

"European airspace will be a single continuum with the only distinction being between Managed and Unmanaged airspace. In Managed Airspace information of all traffic is shared and the predetermined separator is the separation provision service provider while in Unmanaged Airspace traffic may not share information and the predetermined separator is the airspace user. The role of separator in managed airspace may be delegated."

The plans are that the European airspace organisation is simplified into only three categories. The current airspace classification is replaced by a new model consisting of 3 airspace categories (N, K and U) where: N and U are the ConOps final categories (Managed and Unmanaged) and K is a category which will then disappear. K stands for Known Traffic Environment within which all traffic is known to ATS either with position only or with flight intentions as well. Thus according to SESAR D3 the airspace will be finally designated in two categories (see Figure 2-6).

• “managed”, where information on all traffic is shared and the ANSP is the pre-determined separator, but the role of the separator may be delegated to the flight crew with pre-defined rules.

• Low-Mid Complexity/Density o 2D routes o Air Traffic Service Provides responsible for the separation. Employed

ASAS-SS (Airborne Separation Assurance System - Self Separation)

• Very High Density traffic o Definition of 3D-PNR tubes (Point-of-no-return) o Definition of 2D-RNP/STAR (Required Navigation Performance/

Standard Arrival Route) o Closely spaced, separated routes






o Air Traffic Service Provides responsible for the separation. Employed ASAS-SA/SM (ASAS - Situation Awareness/ Sequencing and Merging)

• “unmanaged”, where the pre-determined separator is the airspace user. It is comparable with the airspace F and G of today’s airspace structure. The aircraft is flying according visual flight rules (VFR).

• Low Density traffic o Free and fixed routes o Aircraft Self separation o Similar to current "Class G airspace"

Managed AirspaceTrajectory Managed User Preferred Routing Environment

Separator: ANSP (may be delegated)

High Density Area (defined in space and time)Route structures deployed

for capacity reasons Separator: ANSP (may be delegated) Unmanaged Airspace

Separator – Airspace User

Level TBD

Unmanaged AirspaceSeparator – Airspace

User

Dynamic and variable airspace

reservations

Figure 2-6 SESAR airspace structure

In managed airspace, particularly in the cruising level regime, user preferred routing will apply without the need to adhere to a fixed route structure. Free routing is made available for Airspace users in 2 steps (flight in cruise above a certain level in large airspace areas – typically FAB, and then from TOC to TOD). Route structures will however be available for operations that require such support. In either case the user will share a trajectory the execution of which is subject to an appropriate clearance.

Under some specific circumstances a fixed route structure will be compulsory for all the Airspace users. It is recognised that in especially congested airspace, the trade off between flight efficiency and capacity will require that a fixed route structure will be used to enable the required capacity. The goal is to guarantee a given level of aircraft throughput ensuring the same level of safety. If the traffic density no longer needs fixed route procedures, the route structure will be suspended and Airspace users have the permission not to adhere anymore to a specific route structure. Where major hubs are close, the entire area below a certain level will be operated as an extended terminal area, with route structures eventually extending also into en-route airspace to manage the climbing and descending flows from and into the airports concerned. User preferred routings will also have to take into account the airspace volumes established for the operation of diverse (mainly military) aerial activities.

In the ATM Target Concept airspace is used in a highly flexible manner. It will be treated as a single continuum, minimising the need for traffic segregation and allowing trajectory








management with only a minimum of distortion due to the use of pre-determined airspace and/or route structures. Any specific airspace users’ needs which impose operational constraints in both space and time (e.g. military, test flights) will be accommodated through segregation. The impact will however be minimised through more accurate planning, time management and level segmentation of the segregation, and procedures that can flexibly manage real-time changes to volumes and times and promptly return any unused segregated airspace to general use. Flexible military structures give airspace designers the ability to delineate ad-hoc structures at short notice to respond to short-term airspace users' requirements. FDP systems are updated to support dynamically configurable airspace.

The organisation of the future airspace by means of the Advanced Flexible Use of Airspace concepts (AFUA) is a key element in improving the civil-military cooperation and in increasing capacity for all Airspace Users. The AFUA is a concept in which the airspace is considered as a single entity that is available to all users. The idea is to be able to modify the airspace in a dynamic manner in which volumes of airspaces are changed taking into account user preferences after a collaborative process in which all the stakeholders took part - civil and military authorities will cooperate together to modify the airspace structure according to their needs and requirements. The aim will be to replace fixed airspace structures with volumes of airspace to be made available in a dynamic manner, including cross-border and multi-State arrangements, on the basis of the close cooperation between civil and military authorities. Embodied within the Network Management function will be an airspace reservation process to facilitate this, but such reservations should be temporary, created only when required and be tailored to meet the needs of specific missions.

The main assumptions upon which the airspace organization and management is based are the following:

• Full application of agreed Flexible Use of Airspace (FUA) concepts will be in place in all States by 2020 providing the basis for the next step of AFUA;

• Equal consideration will be given to meeting the needs of civil airspace users and military requirements;

• Protection of secure and sensitive military data will be assured;

• Agreed rules for certain priority procedures to enable military operations (e.g., National obligations and International commitments) to be fulfilled will be applied;

• States’ sovereignty and responsibility for airspace will remain.

SESAR's concept is based on a trajectory-based approach in which airspace users have the possibility to determine their own trajectory according to their own preferences. Airspace users can be both civil entities and military authorities. The trajectories defined by the civil authorities will be related to the business value while the military authority will define trajectories to achieve a determined mission. However, the trajectory defined in SESAR relies on the concept that the trajectory is owned by the user. This concept leads that in standard situation the users have full responsibility over their operation.

Under this premise, the main challenges to the integration of UASs into the Managed Airspace defined within the SESAR framework is safety.






• The level of safety has to be kept according to the legislation and, hence, UAS are required to have the following minimum set of capabilities:

o UAS are able to be used when and where separation is provided by ATC and radio communication can be performed without latency.

o UAS are able to be used when and where separation is facilitated by ATC information. For this kind of operation, collision avoidance is easier to ensure as for operating in uncontrolled / unmanaged airspace. This is due to the fact, that the surrounding air traffic is known, and follows ATC instructions. Only those aircraft, performing unintended manoeuvres, or just violating the airspace are enhancing the probability of air-proximities which have to become de-conflicted.

This is due to the fact that UAVs are aircraft that can fly autonomously. They can operate a wide variety of missions, and in emergencies situation have the possibility to be controlled by a ground control station (see Figure 2-7). Normally the voice communication between UAS control station and ATC is relayed via the UAV. Only in exceptions a direct communication is foreseen.

Figure 2-7 UAS Integration into Managed Airspace

In Unmanaged Airspace (see Figure 2-1), the following safety requirements need to be fulfilled: UAS need to have a full self separation provision and traffic avoidance capabilities (see/sense-and-avoid). These capabilities can be either performed through a high level of autonomy or by a pilot. However, they are able to separate without any help from outside the UAS system. Typically, the separation function is made by the UAV that has to “search the sky” for surrounding traffic and alter the route accordingly. The collision avoidance is then provided by autonomous onboard equipment. Nevertheless it must be noted that the


NAV/FMS Other Aircraft

VHF SSR TransponderUAV

Direct link

Air Traffic Control UAS Ground Control Station







“right of way” rules are depending mostly on the type of aircraft, regardless whether it is manned or unmanned. If a UAV must avoid any other air traffic, this will not be in accordance with current law worldwide. To be in line with the current rules of the air, it must not be excluded that a UAV also may have the “right of way”, and other air traffic will have to change course to assure the safety of a UAV.

Figure 2-8 UAS Integration into Unmanaged Airspace

Limitations of SESAR airspace

The air traffic services that will be provided in “managed airspace” have not been defined yet. They could be similar to the current class C or D airspace, whereas the “unmanaged airspace” situation could be similar to current class G airspace. The type of flight, the separation and service provided, speed limitations, communications and clearance requirements will be based on current procedures, but are to be defined. Also the transition level (height) between managed and unmanaged airspace has yet to be defined.

Finally it is unclear which flight rules are applied in the unmanaged airspace and which separation standards have to be maintained, e.g. distance from other aircraft, from clouds and from obstacles, etc.

2.4.2 En-route and Approach ATC

Approach control is responsible for control of the air traffic in the terminal airspace surrounding an airport/ aerodrome including arriving and departing aircraft.

UAS Ground Control Station

UAV

Other Aircraft NAV/FMS

Direct link







En-route ATC is responsible for the provision of air traffic control to aircraft after departure and before arrival, i.e. those aircraft which are not controlled by approach ATC or aerodrome ATC.

Currently the control of the aircraft is based on radar (primary and secondary radar) as the main surveillance infrastructure. Additionally tools like short term confliction alert (STCA) support the controllers in their work. Aircraft intent and precise trajectories are unknown to them. Rather flight plan information, mostly in form of flight strips, is their main source for planning activities. However the information contained herein is not very precise, e.g. sector entry times and times when abeam a certain navaid, or a not updated in real time. Thus the potential for tactical and strategic planning is limited by the accurateness of the available data.

To overcome this shortcomings one of the main ideas of the operational concept proposed in SESAR is a trajectory-based approach in which Airspace and Airport users share real time information. SESAR's goal is to achieve a system in which strategic and tactical planning is made taking into account the latest trajectory information. Furthermore, all the decisions concerning the ATM system will be taken in a collaborative manner between all stake-holders.


"The Business/ Mission trajectories express the intentions of the airspace user and the trajectory is developed with a view to achieving the best possible outcome for the flight concerned. Any intervention with this trajectory can reduce the prospects of achieving the desired outcome: even unsolicited ‘directs’ can result in unwanted distortions. While it is recognised that for separation provision reasons it is usually impractical to have an operation with no intervention at all, it is important that all tactical interventions are considered at the trajectory level and not only at the immediate aircraft level. A tactical intervention that is focused only on the aircraft without taking account of the wider impact on the trajectories concerned may result in distortions of the trajectory which can be avoided if a broader view is taken. This broader view is enabled by the SESAR information sharing environment. In this way, if several options are available for implementing an unavoidable intervention, the one with the least impact on the overall trajectory, as well as all other trajectories concerned, can be identified and used on a systematic basis."

The major impact of SESAR for the en-route phase is the use of the 4-D trajectory. The traffic flow will be the result of a renegotiation process in which ATM stake-holders will take active part. During this process all airspace users will be taken into account with the task to determine the optimal strategy in terms of economical benefits, environmental impact and the last but not the least safety issues.

The trajectory-based approach underlines three important aspects concerning trajectory's characteristic:

1. The Business/Mission Trajectory: aircraft trajectory is the key element in the ATM system. When we consider military operation, the trajectory represents the mission while for







civil application is the business. The trajectories defined by the Airspace users have to be regarded as the optimal ATM solution. Small changes of this aircraft flow plan means to further from the best ATM solution.

2. Trajectory Ownership: the trajectory is owned by the airspace user as it will gain the business value of that aircraft movement. In normal circumstances, the airspace user has the responsibility over the trajectory.

3. 4D trajectories: the trajectory will be described with high precision in all 4 dimensions. The trajectory will be shared and continuously updated from all those capabilities that are aimed at the task. Only those flights that cannot comply with SESAR trajectory management will be allowed to generate the trajectory from the flight plan.

The En-Route and Approach ATC systems will transition from using specific, pre-established, direct sub-system to sub-system data exchange to information sharing through SWIM, together with more reliance on data and services provided by systems owned by other stakeholders. This will depend on a supporting infrastructure, including security and supervision rules, policies and services. Coflight and iTEC, currently being implemented in Europe, are projects providing the first step towards a new generation of standardised component based systems. They will deliver flight information sharing and Air-Ground cooperation services. Initial SWIM services will be provided either directly from enhanced sub-systems or through an integration layer added to legacy sub-systems. This will be followed by a transition to systems based on standardised components and making use of the Common ATM Reference Model.

On a functional level, the eFDPs will provide support for improved conflict prediction, coordination and transfer, and the introduction of multi-sector planning and 2D precision clearances. Later, the En-Route and Approach ATC sub-systems will evolve to manage airspace users’ trajectory requests and finally to manage all aspects of 4D trajectories. Support will also be provided to allow increased delegation of responsibilities from controllers, taking advantage of improved aircraft capabilities enabling self-separation and sequencing. This will be accompanied by updates to ground Safety Nets sub-systems to reduce false alerting and to provide focused alerting for mixed traffic operations.

AMAN will be initially improved to provide sequencing information into the local En-Route environment, later there will be more integration of DMAN and AMAN from adjacent airports and use of the aircraft’s capability to handle Controlled Time of Overfly (CTO) on multiple waypoints.

Spacing task will be delegated to the cockpit using ASAS applications. The objective is to redistribute tasks related to sequencing (e.g. in-trail following) and merging of traffics between the controllers and the flight crews. The controllers are going to be provided with a new set of instructions asking, for example, the flight crews to establish and to maintain a given time or distance related to a designated aircraft. Pilots will manage the course of the flight during this task whereas Controllers will take over monitoring task. This means that airborne separation assurance functions must be available to enable delegation of spacing tasks to the cockpit and a clear set of standardised procedures must have been established.

Increased usage of controller pilot data link (CPDLC): Controller/ aircrew data communications is most beneficial for routine operations, when the use of voice







communication is considered less efficient or impossible (e.g. flight still in up-stream sector), thereby reducing voice channel use. Its implementation will significantly change the way pilots and controllers communicate. Standardised procedures for using datalink have to be established. Also the loss of party line effect has to be recognised and has to substituted by other means of information where needed

Dynamic airspace management processes will provide support to local, sub-regional, and regional facilities, and will eventually support the dynamic transfer of sectors between ACCs enabling management of local resources to reflect daily variations in traffic patterns.

2.4.3 Aerodrome ATC

This air traffic service within the ATM operations is responsible for the control of aircraft at the aerodrome, consisting of stands, taxiways and runways, and control of aircraft in the airspace directly surrounding the aerodrome. The control of the aircraft is mainly based upon visual reference but is supported by surveillance infrastructure, e.g. ground radar.

Terminal Manoeuvre Areas are airspace region affected by high traffic density. In this area an efficient route organization combined with a ground and airborne capabilities has to be deployed

• to optimize the aircraft throughput • to ensure the highest level of safety • to minimize the environmental impact

These requirements may be achieved only at the cost of imposing some constraints on some specific trajectories. The aim is to maximize the benefit of the all airspace and airport users although some specific airlines may be affected by those constraints.

The optimum aircraft throughput will be achieved using:

• actions given by ATC • spacing instructions executed by the flight crew

The controller and the flight crew actions can be supported by sequencing tools such as the AMAN and DMAN. These software tools will assist ATC and flight crew to take a decision concerning the option to choose to gain the optimal departure and arrival procedure.

According to SESAR target concept, for high density terminal areas (TMA) two different types of operations are envisage to separate departure and arrival routes, the vertical components of which can be defined by either ([2]):

• Level windows for crossing points (“cones” with maximum and minimum levels) enabling aircraft to fly closer to optimum trajectories, when traffic density allows, providing an optimum fuel efficient and environmental friendly approach profile (see Figure 2-9).






• Aircraft being required to fly within “tubes” when traffic density is highest to provide maximum runway throughput and minimising holding delays (Figure 2-10).

Therefore, UAS intended to fly into high density TMAs should be able to cope with this type of operations in order to allow a seamless integration in the airspace system. However, at this time those procedures are defined conceptually in a very first stage and therefore it is impossible to clearly describe the intended operations in detail. It is expected that the above mentioned types of operations need to be assessed and validated within simulation trials.

Figure 2-9 Departure/Arrival routes for high-complexity terminal area using cones

Figure 2-10 Departure/Arrival routes for high-complexity terminal area using tubes

TMAs that are affected by a low traffic density can operate assuring the optimal route for all trajectories. This will be ensured setting in the airspace merging point in which aircraft flying from different routes will converge in the optimal way. The number and position of the merging point will be designed in such a way to optimize runway throughput while maintaining the same level of safety.

In the Pre-SWIM phase (2008-2010), the existing Airport and Aerodrome ATC sub-systems (Departure Manager - DMAN, Surface Manger - SMAN and Runway usage management) providing the first generation of integrated airport operations controllers' tools are further developed to meet the Airport-CDM (Collaborative Decision Making) concept (through airport operations centres). Aerodrome ATC and Airport Demand and Capacity management sub-systems are introduced in support of strategic and pre-tactical airport operational planning.

A secure SWIM infrastructure, supported from 2008 by the evolution towards common ATM Reference Model, is expected to be available by 2013. A first set of services will be








available around the same time and new services will be added, as needed, up to 2020. Coupled to the exchange of information via SWIM, the integration of local Aerodrome ATC sub-systems will provide major improvements to queue management. Further improvements will be derived from the introduction of a new Airport system, Environment Management, as well as from enhanced Turn-around management supporting the 'En-Route to En-Route' concept and from enhanced runway management (separations based on dynamic wake-vortex information). In parallel, a new generation of TWR Controller Working Position will fully support the features brought up by the integration of these tools.

As a final step (2013-2015), enhancement of airport ground equipments will allow provision of advanced guidance service to aircraft and airport vehicles combined with routing, whilst in high density/complexity airport context, sequence management tools will be enhanced to cover the needs of multiple airports within the same TMA.

Automated systems and newly introduced capabilities in surface movement, guidance and control systems will support all-weather operations of airports. Additional surface movement, guidance and control capabilities like A-SMGCS are used to: Enhance safety by detecting traffic incursions not only on the runway. Support optimal planning of taxi routes and other surface movements (including vehicles) in the strategic and pre-tactical phases. Assist the controllers in guiding movements on the ground. Data link capabilities are used to communicate clearances and information to the Pilot and to inform the pilot about taxi routes and changes to taxi routes, stand allocations, etc.

This means that an upgrade of airside infrastructure to make full use of new functionalities is necessary (e.g. surveillance systems) and ground and airborne systems have to be compatible and standardised.

2.4.4 Airport Operations

Airports will be part of the ATM network and they will be integrated within the concept of "En-route to en-route". This concept is based on the idea that aircraft turnaround and flight operation are considered as a single event that occurs one after the other one.


"The trajectory management focus of the ATM Target Concept extends to include the airports to address the airport capacity issue which is the key challenge in the 2020 timeframe. Runway throughput must be optimised to achieve the airport capacity targets as defined in D2. This requires a spectrum of measures ranging from long-term infrastructure development, through realistic scheduling, demand and capacity balancing, queue management and runway throughput improvements."

High density traffic airports will be supported by cluster of airports placed in the vicinity. To do so a centralized and harmonized ATM network is needed. The aim is to assure to maximize runway throughput while maintaining the same level of safety.







The Surface Manager (SMAN) will communicate with the Guidance and Control System (A-SMGCS) to identify the optimal movement plans determining the surface movements that optimizes resources usage. Furthermore SMAN will work in conjunction with the AMAN/DMAN to determine the optimal arrival and departure sequence.

Airport planning process will consist of two different operational processes:

• Airport Resource Planning; • Airport Resource and Capacity Plan Management.

The first one deals with the plan of the airport resources assuring that they are allocated in the optimal manner. Based on the capacity estimation of the available resources, an initial Airport Resource Allocation and Capacity Plan is started. It comprehends:

• the evaluation of the availability of the resources; • a number of airport configuration in which for instance runways, taxiways, gates

and terminal buildings/facilities are taken into account; • capacity estimation for each process. It will be taken into consideration external

conditions like traffic mix, weather conditions, etc.

The aim of the initial plan is the Slot Coordination Process that consists in matching traffic demand with airport facilities. The aim is to optimize the aircraft throughput at the airport guaranteeing the same level of safety. An airport operational plan will be established between the airport operators, ANSP and Airspace Users though a collaborative process in which each user will give his requirements.

Airport Resource and Capacity Plan Management is the operation that is performed in the context of the planning process. The goal is to provide the airport operators with accurate and reliable demand information. The plan can change taking into account the constraints on the day of the operation. Requirements between the CDM partners will be also taken into consideration. A demand will be forecast based on:

• Airspace Users’ intentions. It is specified by the intended schedule of operations and/or the Shared Business Trajectories;

• Airport information. This information will be provided by the capabilities described in SWIM. They will include landing time constraints, turnaround time, airport capacity and taxiing time.

If demand exceeds current capacity due to the effect of unpredictable factors, the consequences are evaluated and a collaborative process is implemented between all Airspace users to define the optimal strategy.

2.4.5 Flow management

Airspace is a resource with limitations. If the demand imposed by airspace users is exceeding the available capacity then the usage of airspace has to be managed by a mechanism which protects control sectors from overload while keeping economical penalties as low as possible. Flow measures are intended to ensure that traffic loads remain within designated limits and are designed to regulate traffic streams, not individual flights. This mechanism is known as Air Traffic Flow and Capacity Management (ATFCM). In Europe this ATFCM is performed by the Central Flow Management Unit (CFMU) of Eurocontrol.







Eurocontrol's CFMU provides ATFCM services on behalf of air navigation services and aircraft operators. On the one hand, CFMU provides flight plan data to air navigation services and advice on flight planning to aircraft operators. On the other hand, CFMU plays an important role in balancing demand and capacity, protecting ACC sectors from overloads and keeping delays as small as possible.

The Flow and Capacity Management service, comprising

• strategic activities (long term demand and capacity matching) • pre tactical activities (next day’s capacity and network management) • tactical activities (balancing in near real time demand and capacity) • crisis situation management (co-ordinating and implementing remedial actions in

such events)

will evolve from a predominantly slot allocation mechanism to the concept of optimisation of traffic patterns and of capacity management. This transition will be supported by stronger collaboration with ATM partners, enhanced information exchange and data sharing and a closer interaction with airspace management partners and with airports. This collaborative planning will be reflected in the Network Operations Plan (NOP). The collaborative planning shall ensure that capacity matches demand making the whole ATM network more efficient.

Strategic Activities

Strategic activities take place from several months until a few days before a flight is conducted. Airspace users notify their demand in the form of flight intentions which are collated by the ATFCM Organisation every half year. The approximate flight times, departure and arrival points and proposed type of aircraft are sufficient data to provide the initial estimates for traffic demand. For missing data, especially for General Aviation flights and for military operations, figures are extracted from historical data and included.

During the Strategic Phase research, planning and co-ordination activities are carried out towards early identification of major demand or capacity problems with the ATC system and towards planning of corrective actions. The most important and far-reaching tasks with CFMU involvement are the elaboration of a European capacity plan for the forthcoming year and the participation in the preparation, implementation and use of the Route Network

Requests for reservations for civil and military operations are processed and inserted as they are received along with changes in airport capabilities. Major sporting and cultural events that generate significant spikes in the normal traffic loadings are incorporated into the totals. While these events require special planning at the local and regional level, their impact on the overall network may be minimal but still needs to be evaluated. This traffic and airspace demand is projected onto the available sectors to provide both a network demand, and a local demand. Early in the planning phase this projection is done by estimating typical days and average traffic but, as the phase matures, the emphasis changes to a day by day analysis. The result of this process is the estimated traffic demand for the day of operation at all levels from the individual sector to the Network as a whole.







Pre-tactical Activities

The pre-tactical planning phase covers the timeframe starting 7 days in advance of the day of operation and reaches to about 2 hours before the event on the day of operation.

The CFMU in close co-operation with the Flow Management Positions and Aircraft Operators execute pre-tactical activities in the days before the day of operation. The emphasis is in capacity and network management, and as such involving more and more airspace management activities. During the pre-tactical phase the flow management balances demand and capacity in order to achieve performance targets and to meet airspace user needs. Where a short term deficiency is identified, solutions for changes on routes and traffic flows are proposed to ANSPs.

The Network Management Cell (NMC) performs analysis of traffic patterns and re-routeing of traffic flows. The NMC also conducts the operational ATFCM planning ahead of the day of operation, normally from Day minus 6 to Day minus 1.

The NMC co-ordinates and collaborates with the Area Control Centres (ACCs) and Aircraft Operators (AOs) via the telephone, daily teleconferences and various publications, and creates the daily ATFM Plan, taking into account factors such as:

• the traffic patterns of scheduled and leisure operators for that day • military activities which might take place due to more reliable weather forecasts • the anticipated flows of North Atlantic Traffic, both Westbound and Eastbound • the expected capacities and sectorisation provided by the Area Control Centres • airport capacities • special events

The Tactical Activities

The pre-tactical phase ends two hours before the push-back (Estimated Off-Block Time) for an individual flight (the tactical phase) and is normally associated with the filing of the IFR flight plan. Since aviation is a dynamic business, last minute changes will always occur. The degree of flexibility to adapt capacity is directly linked to the time available before the event to make the necessary changes and the ability to make available the pertinent data to all concerned partners in time.

The main role of ATFCM on the day of operations is to monitor, anticipate and react to the traffic situation and thus to balance in almost real time traffic demand and capacity on the current operational day. This includes the allocation of individual departure times, re-routings to avoid bottlenecks and alternative flight profiles to maximise efficiency. The main functions are:

• The short-term optimisation of the capacity in regard of the actual traffic. • The presentation of the actual and planned traffic situation to enable CFMU, FMPs

and Aircraft Operators to monitor and modify the operation of the ATFM plan as required on the day of operation.

• The analysis and implementation of the re-routings and FL capping







• The management of the traffic demand in regard of the capacity, using the Computer Assisted Slot Allocation (CASA) system.

• The information and assistance to airline operators and ATC in their real-time operations.

Critical Events Management

Serious constraints may build up very rapidly as the result of technical, social or political problems and adversely disturb the air traffic in the airspace of the ECAC States. Such events are occurring daily and have often a local limited impact. The CFMU is the focal point for exchanging information and co-ordinating remedial actions, allowing quick and efficient reactions.

Flight Planning

To manage the flow of air traffic the CFMU has to have access to flight plans information of every aircraft that is planning to fly in the airspace. The operations of centralised flight plan processing (rationalising reception, validation, acceptance and distribution of flight plan data) and flight data for ATFCM planning are progressively developed to ensure better consistency of initial flight plan data across Europe through the establishment of a reference flight plan data repository. More flexibility will be provided by the flight planning process and tighter links ensured between the more dynamic airspace database and flight planning partners.

The Flight planning fulfils three primary services:

• a centralised flight plan processing service for the States within the CFMU area with the objective of rationalising reception, validation, acceptance and distribution of Repetitive Flight Plan (RPL) and Filed Flight Plan (FPL) data.

• provision of flight data for ATFM planning, monitoring and slot allocation as required in the European ATFM concept.

• assurance of flight plan consistency across Europe and management of its repository.

Network Operations Plan

The Network Operations Plan (NOP) provides a consolidated view of the forecast seasonal ATFCM situation: traffic and capacity forecast, bottlenecks identification and description of the associated ATFCM and ASM measures.

It’s the final result of the operations planning process which consolidates inputs from partners involved in ATM operations (ANSPs, Airports, Airspace Users, Military…) and from EUROCONTROL Units in charge of Flow, Capacity, Airspace Management, Airports and civil military coordination. The Network Operations Plan is an output of the Dynamic Management of European Airspace Network (DMEAN) Framework Programme.






2.4.6 Development & Management of the Network Operations Plan

The SESAR Deliverable 3 [2] states:

"In parallel with all the phases of individual Business Trajectory planning, a CDM process is in place in which all stakeholders share the necessary information to ensure the long and short-term stability and efficiency of the ATM system and to ensure that the necessary set of ATM services can be delivered on the day of operation. The key tool used to ensure a common view of the network situation will be the “Network Operations Plan” (NOP). The NOP is a dynamic rolling plan for continuous operations rather than a series of discrete daily plans which draws on the latest available information being shared in the system. The NOP works with a set of collaborative applications providing access to traffic demand, airspace and airport capacity and constraints, scenarios to assist in managing diverse events and simulation tools for scenario modelling. The aim of the NOP is to facilitate the processes needed to reach agreements on demand and capacity."

The planning of the traffic flow occurs at different stages, first the business trajectory is defined this operation is defined from 1 year in advance and takes into account all the economical reasons to pursue a determined trajectory. It follows the planning that last from few hours in advance until 1 year. The aim is to provide the optimal trajectory taking into account changes in the ATM system. The last is the executed trajectory, changes can occur to optimize the overall ATM system. The entire process can be regarded as a continuous collaborative refinement in which all the ATM stakeholder take part in the decision process to pursue the optimal ATM solution in terms of economical return, environmental impact and safety regulations (see Figure 2-11).

Figure 2-11 Traffic flow planning

Business Development

Planning Execution

Years Days Minutes

2.4.7 SWIM

The most important characteristics visible from SESAR is the trajectory management approach to handling flights on the one hand and a shared information environment which is the main underpinning of all the air traffic management functions on the other. This shared information environment extends to include aircraft on the ground and in the air. Current ATM systems are based in a point-to-point exchange of information. This means,








each time a new system requiring data from a pre-existing application is built, a series of ad-hoc interfaces are developed to interface between the two applications.

As a result of this situation, every time the ATM system is expanded, we are also adding complexity to it in the form of new dedicated interfaces, which are costly to build and to maintain.

In addition there is a lack of flexibility in the system due to the fact that hard-wiring the information between two systems (or facilities) prevents other system to share it. This results in the following problems:

• There is no easy means to access live operations information • It is complicated to access recorded information • Inconsistency between information provided by different actors. • Inefficient coordination between involved actors. • Stakeholders unable to receive all the information needed.

New concepts and processes to be implemented in the ATM arena claim for a more extensive data sharing between actors. Information should be available for everybody in a timely and consistent manner. All the actors should be able to manage the same information at the same time in order to gain operational efficiency.

System Wide Information Management (SWIM) is been proposed as the cornerstone for this transformation. This is a distributed processing environment which replaces data level interoperability and closely coupled interfaces with an open, flexible, modular and secure data architecture totally transparent to users and their applications. The aim of the System-Wide Information Management system is to combine the forces of all suppliers of ATM information so as to assemble the best possible integrated picture of the past, present and (planned) future state of the ATM situation. This provides the foundation for improved decision making by all ATM partners, including the military, during their strategic, pre-tactical and tactical planning processes, as well as real-time operations and post-flight activities. This allows all partners to enhance their planning processes, improve predictability and stability and to optimise their services.

Instead of developing and implementing specific solutions for sharing data between specific pairs of applications, SWIM implements a common infrastructure and set of processes for sharing and managing data among all the ATM key players in a secure and timely manner. One of the main benefits of SWIM is that once the data is published, it is made available for any authorized application requiring it.

System-Wide Information Management ensures the delivery of timely and accurate data to support the flexible management of airspace, capacity management and to initiate the optimisation of user preferred trajectories. The system is accessible by all partners, provides full airspace information to users and is updated in real time by civil and military organisations.






As it can be seen in Figure 2-12, SWIM will be able to reduce the overall complexity of the current ATM system by reducing the number of required interfaces and will facilitate the data sharing among the relevant stakeholders.

SWIMSWIM

Figure 2-12 Conventional structure vs. SWIM enabled system

At this moment it is not yet decided how SWIM will be implemented but most likely it will implement service oriented architecture (SOA) that will allow applications to be integrated without modifications. SWIM will allow the connection of both SWIM oriented applications and legacy applications in current use (those running in today’s ATS units).

Main benefits of SWIM solutions can be summarized as follows:

• New information consumer applications can be developed without requiring modification to existing information producer applications

• The use of common protocols, interfaces, etc allows software reusing, leading to future saving in new implementations.

• The effort required to interconnect new systems is greatly reduced. • Common information security functions such as authentication, access control,

confidentiality and integrity, may be used by all applications. • Use of a common core infrastructure will reduce overall implementation cost. • Easy access to critical ATM data for all stakeholders involved.

From the UAS perspective, it is fundamental to explore and analyze the type of data UAS will need to both publish and retrieve from SWIM in order to assure the smooth introduction of those vehicles in controlled airspace. It is generally agreed that if UAS want to access non segregated airspace they will need to comply with the same restrictions and requirements that manned aviations do, so UAS interaction with SWIM is guaranteed and compatibility should be assured in order to avoid future problems when dealing with the interaction between manned and unmanned aviation.

Work package 4 of INOUI will perform an initial analysis of the type of data that UAS will exchange with SWIM, the new actors involved, and the authorization level required by each of them.








2.4.8 Airspace users

The ATM system has to meet with the needs of several airspace users or aircraft operators, each of them having their own requirements and missions. Differences between those airspace users exist mainly in the types of aircraft being used, with their unique characteristics and capabilities, and in the planning horizon for using the airspace, which can range from scheduled months in advance to ad hoc or flights on short notice.

Airspace users operations concerns ATM related aspects of flight operations including Flight Planning, Flight Briefing, Aircraft Management, Fleet Management, Operations Management, and Schedule Management.

The aircraft operators can be categorised as follows:

Scheduled Aircraft Operators: their strategic target is to sell their aircraft transport capacity to the public and to gain the greatest possible share in the transport market. They prefer a system that will let them plan according to demand and fly according to schedule in a safe, expeditious and cost effective manner. Scheduled Aircraft Operators run sophisticated decision support tools during the scheduling and planning of their operations. Advanced monitoring tools allow them to detect unavoidable restrictions. When changes to their plans become necessary, they negotiate with ATFCM, ATS and Airport Operations actors through CDM processes in order to determine the best possible alternatives. Scheduled Aircraft Operators' requirements and resources are determined well in advance and continuously monitored and adjusted. They actively participate in all the Planning Layers (i.e. Strategic, Pre-Tactical and Tactical).

Charter Aircraft Operators: they are mainly interested in getting the greatest possible flexibility in operations (i.e. departure times) and are sensitive in regard to service costs. They aim at maximising aircraft utilisation. Their requirements and resources are known very late and they can change at the last minute. So although they actively participate in all the Planning Layers (i.e. Strategic, Pre-Tactical and Tactical), they are likely to have more changes in the Pre-Tactical and Tactical Planning Layers than the Scheduled Aircraft Operators.

Executive Aircraft Operators: their business is built on transporting their clients whenever they want, wherever they want. They thus seek maximum flexibility of operations. Their requirements and resources are known very late and they can change at the last minute. They are mainly involved in the Pre-Tactical and Tactical Planning Layer.

General Aviation Aircraft Operators: they interact with the ATM system on a flight by flight basis. The majority of general aviation flights are performed in accordance with the Visual Flight Rules (VFR). The vast majority of flights take place outside terminal areas and do not interfere with the operations of other civil airspace users. Planning of some general aviation activities also involves Airspace Management (e.g. airspace reservations for air shows, gliding, etc). General Aviation Aircraft Operators’ requirements are met by providing information relative to their flights in the most efficient and cost effective manner. Their requirements and resources are generally very limited and flexible and known very late. They are mainly involved in the Pre-Tactical and Tactical Planning Layer.







Military Aircraft Operators: they operate transport aircraft (equipped with navigation and communication devices fulfilling international GAT rules) as well as fighters and other aircraft with limited CNS equipment and following rules for operational air traffic (OAT).

OAT (Military Air Traffic) flights have unforeseeable flight paths (combat training) or ones that are difficult to modify. Because of this, airspaces must be temporarily reserved for them where they can fly without interfering with civil air traffic. OAT may never interfere with GAT and ATC needs to separate OAT and GAT at any times.

With respect to GAT they actively participate in all the Planning Layers (i.e. Strategic, Pre-Tactical and Tactical), but are likely to have more changes in the Pre-Tactical and Tactical Planning Layers than the Scheduled Aircraft Operators. OAT needs special handling and assistance from ATS and/or Air Defence units depending on national organisations and regulations, their requirements and resources are often known at the very last moment (Tactical Planning Layer) and they often have priority over the others. Planning of OAT flights also involves Airspace Management activities (e.g. airspace reservations).

Theoretically UAS operations could fit under each of the above aircraft operators.

The civilian applications for UAS are quickly emerging as a large and lucrative new aerospace market. Due to their nature, UAS have the capability to fulfil a number of key civil airspace operations. The most visible areas where UAS are rapidly gaining momentum are those where manned aircraft are challenged to operate, or is a prohibitively expensive option. In particular, the most common UAS civil operations include dull, long endurance, risky or dangerous missions.

Thanks to the recent maturity in the information communication industry a large number of future UAS civil operation are growing. However it must be noted that the ability for UAS to engage in specific operations is closely coupled to regulations and airworthiness certification. Where existing regulations do not permit the use of future civil UAS operations, a regulatory framework needs to be developed to determine what technologies or procedures are essential. In addition, a demonstration at an early stage to show the safe introduction of these future UAS civil operations should be an objective.

These future operations in managed airspace will depend on the development of procedures and technologies that will enable these vehicles to fly with the same (or higher) level of safety as an onboard pilot controlled aircraft in a mix of air traffic (manned and unmanned).

Besides the specific procedures and technologies deployed in UAS, there are a number of generic UAS civilian operations which may be considered under the following areas:

1. Low altitude surveillance (below flight level 100) - One of the mostly discussed UAS applications are surveillance tasks, especially surveillance in low altitude. Due to the nature of these very different types of operation, they should be described as follows: A. Very low operations

Very low operations are those which will take place near to the ground level and for this reason below the minimum safety altitudes in European counties, (below 500 ft. AGL). As the air traffic in these altitudes is mostly allowed only for helicopters (doing







aerial work or rescue missions), the focus to avoid collisions has also to be set to avoid collisions with ground obstacles (to be observed or inspected). Very low operations have been successfully demonstrated for the following applications:

• Power line inspections • Crop dusting • Building inspections (bridges) • Close area support to local fire brigades • Areal photography

B. Low altitude operations

The major challenge of these UAS applications is their integration into the airspace structures below flight level 100. Here, where in airspace E, F and G no separation is be provided to VFR traffic, collision avoidance is mostly based only on the “see and avoid” principle. Prior to the integration of such UAS in the managed airspace, the capability for the UAS to substitute the “see and avoid” by a “sense and avoid” must be clearly assessed and a way how to assure the function “collision avoidance” must include available techniques as well as mature procedures. Low altitude operations have been successfully demonstrated for the following applications:

• Pipeline surveillance • Border control • Traffic surveillance • Disaster monitoring

2. Cargo flights - The second major civil application category will be the unmanned cargo flight. Therefore the unmanned airplane must be integrated into the air traffic management. Technical problems, like security of the flight critical data links, automatic flight or communication latencies through data link are currently the major concern regarding this type of operations.

3. Station Keeping – This type of operations consists on operating the UAS as a geostationary platform in an altitude of 20 km or more for telecommunication purposes (broadband wireless access, 3G/4G mobile communications, digital audio/video broadcasting) Each UAV would be able to provide services for an area with a diameter of approx. 230 km. For example it would be possible to provide Great Britain with mobile phones frequencies with six stationary UAV (like airships, dirigibles, or blimps). This is one of the most interesting operations but also could be the most challenging one due to the required endurance of the UAS because of its long flying times (it is expected to be months).

It must be noted that UAS specific operations may vary a lot depending on the complexity of each flight from the above, and therefore the intention must not be to classify UAS operations into groups but to learn and incorporate new operations into the UAS community.

In addition to the above, the UAS operation profile may also be very different depending on the type of UAS platform used, and all possibilities must be considered. For example, a







Vertical Takeoff & Landing (VTOL) operation profile, typically rotary wing UAS; a Man Portable - light enough to be back-packed by an individual and launched by hand throwing or sling-shot mechanism.







3 Description of ATM Environment – UAS Segment

3.1 SES Architecture and Airspace Users

The aim of this section is to identify how well the airspace user’s concept described in SESAR match with the UAS concept and its operation.

SESAR clearly define UASs as an airspace user, however none of the current specifications has specifically taken into account the singularities affecting the UAS operations. As a result it is necessary to review each of the concepts in order to identify those modifications required to been able to smoothly include UASs under the SESAR airspace user concept.

3.1.1 Airspace User Operations Centre (AOC)

The AOC concept has been defined in SESAR bearing in mind the possible responsibilities and activities associated to what today is know as Airline Operating Centre. From an UAS perspective is unlikely that an AOC, as it is currently defined, exists. It is more likely that UAS intended to fly in managed airspace will need a similar support office with its special requirements from an operational point of view to allow the flight planning process and trajectory coordination. Thus an AOC alike service will be required for civil UAS operations, also to participate in SWIM.

Main envisioned responsibilities for this actor are the following ones (focused on UAS): • Trajectory management, for non OAT (civil UASs) will be required to comply with

the trajectory management procedures, as any other manned vehicle, to allow ANSP optimize the trajectory allocation planning process. Certain emergency operations (e.g. police, fire fighters) could be treated with priority rights which will be given to them by the authorities (ANSP). However, national regulations should be adapted to clearly articulate this type of operation and avoid confusion.

• De-icing management; those cases when UAS requires de-icing prior to departure, the normal operating procedure at the airport will apply. Current first-come-first-serve operation will no longer apply and as a result, the UAS operating centre shall be able to coordinate/ communicate with the De-icing Management System in order to assure de-icing slot assignment for the UAS.

Regarding the main requisites enumerated in SESAR, UAS operator should bear in mind the following ones:

• Communications between AOC similar service and the UAS control station should be done through SWIM.

• Flight planning should be done by publishing 4D trajectories instead of current flight plan data. This is an issue that should require an intensive analysis to determine the feasibility of applying this 4D trajectory concept to the UAS world. UASs in many cases will operate in a way that strategic planning of the whole trajectory seems to be, at least, difficult. Definition of missions in advance is not always possible, and in most cases, only part of the trajectory will be known (the part associated to the flight phase to and from the theatre of operations) but will be impossible to forecast which







is going to be the trajectory inside the theatre of operations due to the changing conditions inside those areas.

3.1.2 Aircraft

As stated in SESAR documentation, “the aircraft is an integral part of the Airspace User Operations” [2] and comprises the whole range of flying objects including the UAS.

The technical architecture associated to the aircraft comprises three main sub-systems:

• Communication: composed by air to ground interoperability and Air to Air information exchange subsystems.

• Navigation: composed of Flight Management, Flight Guidance and positioning subsystems

• Surveillance: composed of traffic, terrain and weather awareness and avoidance systems.

From the UAS perspective several points should be taken into account in order to guarantee UAS compliance. The following subsections will highlight the most important point regarding each of the subsystems.

3.1.2.1 Communications

• UAS control station should be permanently connected to the ATC frequency. In the case of fully autonomous systems, a deeper analysis should be done in order to clarify how those communications are going to be assured. It must be considered that remotely adjustable voice radio has to be on board of an UAV if the radio communication with ATC is relayed via the UAV, which will be normally the case, as no direct communication between ATC and the control station is possible due to radio wave propagation.

• Frequency spectrum requirements for UAS flight operations relevant datalinks (i.e. command control, and communications, also called C3 datalink) need still to be defined and it is not yet clear which is going to be the band assigned to each of them. To assure the correct protection of the frequencies, it is likely to be the aeronautical band, but the scarce number of frequencies currently available is a problem that must be solved. Furthermore it must be considered that depending on where in the world UAS are in operation, different frequency bands have to be used. Interoperability is therefore not assured currently. The issue of C3 datalink frequencies are on the agenda of the next WRC meeting in 2011.

• Flight operations relevant datalinks onboard UAS (C3 datalink) should comply with the minimum RCP (Required Communication Performance) established for a given airspace. Those minimums should be defined in the near term by an authorized regulator and will be associated to different performance parameters like latency, availability, integrity, security, predictability, throughput and coverage, etc.

• SWIM interoperability should be correctly addressed to assure the correct exchange of information between UAS and any other stakeholder. This issue will be analyzed in deep in INOUI WP4.

• UAS flight management system should be able to deal with the ATC communications, specially those clearances and restrictions uplinked via datalink.







In the case of fully autonomous systems, the FMS should be able to accept or refuse those clearances and restrictions in a timely manner to maintain a seamless communication with ATC. Additionally the C3 datalink reception range has to be considered.

• UAS shall be fitted with advanced functionalities like taxi path or route uplink which will be common use ion manned aviation by 2020.

3.1.2.2 Navigation

• UAS control stations should be fitted with state of the art avionics alike systems capable of interoperating with those collaborative equipments already installed in manned aviation. However all this equipment must be capable of being remotely controlled, as there is no pilot in the cockpit who could do this directly. Examples of this are altimeter, transponder, ACAS or ASAS systems. Please note, that ACAS (e.g. TCAS) are ‘Mitigation of Collision Avoidance’ systems and not truly ‘Navigation’ Systems, unlike ASAS systems, which are extended for navigation purposes.

• To grant UAS access to controlled airspace it is fundamental to certify each UAS navigation performance in terms required navigation performance (RNP), including lateral containment and altitude containment along a segment

• UAS auto-steering systems should be at least as reliable and precise as those currently installed in manned aviation. This includes autopilot and auto-taxi systems.

• UAS should be fitted with Trajectory Management Requirements conformance monitoring to assure an accurate execution of the cleared trajectory and obtain proper alerts in the case of any non-programmed deviation.

3.1.2.3 Surveillance

• UAS should be fitted with systems capable of supporting future self separation concepts like ASAS, otherwise, fully integration of UAS in controlled airspace were separation assurance is been delegated to the pilot will be complicated. Any sense-and-avoid systems onboard the UAS should also be able to cooperate with those systems onboard manned aircrafts to assure a correct situational awareness for all airspace users.

• Existing terrain awareness and avoidance systems should be adapted to its use in UAS. Still not clear how this is going to be done but what is clear is that UAS probability of controlled flight into terrain (CFIT) should remain as low as it is currently for manned aviation.

• As in the previous point, weather awareness and avoidance systems should be adapted to meet UAS requirements. In the case of fully autonomous UAS, response to the system resolutions should be follow automatically with out human intervention but maintaining coordination with ATC, to avoid creating any conflict with other traffic.







3.2 UAS operating in the airspace

Before going to the description of the specificities of the UAS, this section of the document aims at giving a contextual view of the potential use of UAS in the current ATM concept.

Today, Unmanned Aerial Vehicles exist in a wide range from a micro-light model aircraft to the size of an airliner. Fixed wing aircraft, rotary wing aircraft, lighter-than-air vehicles and various types of power plant are known. Even though manned aviation is something really complex to understand, we have been familiar with it for a century. Unmanned Aerial Vehicles are now entering this complicated game. In several aspects, they are completely different from their manned “colleagues” but they have to be operated within a system that has been developed and approved in the course of a century.

UAS are currently authorised to fly in segregated airspace. This type of flight will not be described in this document as it is not really addressing the operational UAS integration which is the goal of the INOUI project.

Indeed, when flying in restricted zones, unmanned and manned aircraft are physically separated (location and/or time) in order to avoid any manned aircraft/UAS encounter. This is a stringent limitation to the UAS use; it is not practicable to allow neither commercial profitable missions nor military missions in peace time. Unless UAS are operated in altitudes below minimum safety altitude, e.g. below 500 ft in missions like crop dusting, which will presumably not create any conflicts with other airspace users.

So, in order to perform really operational missions, the Unmanned Aircraft will have to fly in non segregated airspace, i.e. conventional classes of the airspace shared by its multiples users.

3.2.1 Current airspace classification

An analysis of the complexity of the problem can be based on the operational functions to be performed by a UAS when it is operated in a given type of airspace.

The separation assurance and collision avoidance responsibilities depend on the class of airspace, and on the type of flight rules under which the UAS is flying3. Figure 3-1 depicts these responsibilities.

• Box marked “ATC” : ATC is in charge of providing the function; • Box marked “UASATC“: UAS is in charge of providing the function with the possible

help of ATC; • Box marked “UAS”: UAS is in charge of providing the function (man in the loop or

autonomously).

3 This implies that the UAS has awareness about the airspace it is currently using, i.e. knowing the own position and the structure of the airspace that is geographically defined. The UAS mission preparation will have to include an update of the airspace definition database embedded into the UAS flight management system.






ALLcollision avoidance

VFR/VFR separation

IFR/VFR separation

IFR/IFRseparation

ALLcollision avoidance

VFR/VFR separation

IFR/VFR separation

IFR/IFRseparation

A B C D

ATC ATC ATC

ATC

ATC ATC

ATC

ATC

Controlled AS

E F G

Uncontrolled AS

UASATC UASUASUAS

UASUAS

UAS

UASUASUASUASUASUASUAS

UASATC

UASATC

UASATCUASATC

UASATCUASATC

Airspace classes

Type

s of

fligh

t

Figure 3-1 UAS Separation Assurance and Collision avoidance

The first column on the left hand side of Figure 3-1 shows the two types of functions to be performed to insure a safe traffic and the nature of the traffic to be separated and avoided. Indeed, Air traffic can fly either Visual Flight Rules (VFR) or Instrument Flight Rules (IFR).

The first line is dealing with separation between IFR traffic whereas the second one addresses the separation between VFR and IFR flights. The third line of the table deals with providing separation between traffic flying VFR. The last one deals with the avoidance function which has, in any case, to be performed by the pilot in manned aircraft. This means that dedicated avoidance equipment has to be used in a UAS.

Regarding the columns of the table, each of them represents a class of airspace. Classes A to E airspace are controlled, classes F and G airspace are uncontrolled. This classification is directly linked to the type of services provided by the ATC and, consequently, has an impact on the functions to be performed by aircraft pilots.

In class A airspace, no VFR flights are allowed. Consequently, the only case that has to be addressed is separation between IFR flights. This function is in charge of ATC (green rectangles) which will give flight altitude and bearing instructions to the pilots to prevent any separation loss. The same situation applies for the other controlled classes of airspace (B to E) for the separation between IFR flights.

In class B airspace, VFR flights are allowed and ATC is in charge of providing the separation between all flights, VFR and IFR.








In class C airspace, ATC is in charge of the separation between IFR flights and IFR/ VFR flights. Separation 4between VFR flights is under the responsibility of the pilot who is helped through ATC messages providing traffic information (pink rectangles). A UAS operating VFR in class C airspace would have to process and acknowledge ATC voice messages, acquire other traffic and keep separated from them.

In class D airspace, ATC is only in charge of the separation between IFR flights. Separation between IFR and VFR flights and between VFR flights is under the responsibility of the pilot who is helped though ATC messages providing traffic information. A UAS operating IFR or VFR in class D airspace would have to process and acknowledge ATC voice messages, acquire other traffic and keep separated from them.

In class E airspace, things become significantly more complicated. ATC may not be aware of the presence of some VFR traffic (there is no mandatory radio contact in this class of airspace). Consequently, it can only provide the separation between IFR flights and is not even able to provide traffic information about VFR flights. Separation between IFR and VFR flights and between VFR flights is under the responsibility of the pilots without any clue on their presence (orange rectangles). A UAS operating IFR or VFR in class E airspace would have to process and acknowledge ATC voice messages, acquire other traffic and keep separated from them.

Last but not simplest is the integration of UAS into class F and G airspace. These classes of airspace are uncontrolled and pilots are in charge of managing their flights taking into account the other airspace users. They may have information from other aircraft through self broadcast messages.

3.2.2 UAS pilot’s functions

Regarding the pilot’s function, it can vary from an integrated real time action to control the system (remotely piloting the vehicle for example) to a monitoring activity of a system that can necessitate high level instructions from time to time or even can only require actions in case of emergency.

If fully integrated in the real time control loop, the pilot may have to perform actions requiring basic aircraft control skills or “controller like” proficiency depending on the level of automation of the UAS.

Consequently, the operational categorisation to be defined for the UAS must include pilot’s functions, and more generally UAS operational capabilities related issues.

3.2.3 Operation modes

In order to get a clear vision of the UAS ATM environment, a preliminary analysis of its possible operation modes has to be done. These modes depend on the mission to be performed and the environment in which the system will be used.

4 The term separation is for an action ATC performs. This is not the case when VFR traffic is involved, where „collision avoidance“ of „safety distance“ are more adequate, as this ultimately in responsibility of the pilot. However for the sake of readability separation is further used.






This section of the document depicts 4 operation modes.

3.2.3.1 Mode #1: Visual Line Of Sight 1 (VLOS1)

In this mode called “VLOS1” for Visual Line Of Sight, the pilot has a direct visual contact with the UAV and all relevant air traffic from where a control station (CS) is located (shown in Figure 3-2). This is a VFR operation only and other airspace classification requirements (such as communications, etc) must be met.

In this case, the UAS ATM environment is rather simple. Due to the visual contact constraint, the distance between the pilot on the ground and the UAV is short. As a result, the UAV can only fly at low height, close to the pilot, without any, or low interference with other air traffic.

This mode includes also operations in which the link between ATC and pilot is direct (ground link), LOS from pilot to ATC is not implied (Figure 3-3).

Figure 3-2 UAS mission enabling visual contact operations ATC-pilot communications relayed through the UAV

Figure 3-3 UAS mission enabling visual contact operations Direct ground ATC-pilot communications link







3.2.3.2 Mode #2: Visual Line Of Sight 2 (VLOS2)

This mode VLOS2 is close to mode #1 functionally speaking, the pilot has a direct visual contact with the UAV and its environment from a chase aircraft where an Airborne Control Station (ACS) has been installed (shown in Figure 3-4). For ATM purposes this is a formation flight as prescribed in ICAO Annex 2 para 3.1.8, this can be either a VFR or IFR operation and other airspace classification requirements (such as communications, etc) must be met.

Figure 3-4 UAS mission enabling visual contact operations (ACS)

In this case, the UAS ATM environment is more complex. The UAV has to perform a formation flight, which is already a current practise in the manned aviation world.

To summarize the situation, in these two VLOS operation modes, the UAS pilot is able to perform many tasks in a similar manner as a manned aircraft pilot would do. The UAS operation is effectively transparent to ATC. The pilot acts as if he was onboard the UAV, talking to controllers and following their instructions. Nevertheless, as far as technology is concerned, these two types of operation are significantly different. VLOS1 category of UAV covers very simple systems close to radio controlled models whereas VLOS2 category could cover the current control mode of the Global Hawk when flying at locations where other traffic can be encountered.

3.2.3.3 Mode #3: Line Of Sight (LOS)

The third mode is called LOS (Line Of Sight between aircraft and control station regarding command and control (C2) link and communications). It is more demanding concerning some onboard functions as, for instance, the complicated sense and avoid problem. As shown in Figure 3-5, in such a system, the pilot gets information about the status of the aircraft and sends instructions through one or several C2 links. The link is also used to download the sense and avoid (S&A) function information.

The maximal operation distance of the UAV from its CS is limited by the data link capabilities. In this mode, the pilot has no visual contact with the UAV and its surrounding







environment. The UAV will be expected to operate like a manned aircraft, with the pilot on the ground. The situational awareness of the pilot heavily depends on the information provided by the S&A system and on the interface that gives him this information.

Figure 3-5 UAS mission enabling LOS data link operations (GCS)

3.2.3.4 Mode #4: Beyond Line Of Sight (BLOS)

The fourth mode of operation is a more technically complex one that uses both C2 and communications link through a relay system and is usually Beyond Line Of Sight (BLOS), see Figure 3-6.

As in the previous mode of operation, the UAV operates like a manned aircraft with the pilot on the ground, but transparency to ATC is more difficult to achieve due to the latency of the voice communications. This latency risks inhibiting timely, and conventional, two-way RT exchanges. More importantly this latency impedes the pilot’s ability to respond to ATC instructions. Moreover, the transmission of sense and avoid information will also be delayed. Here again, the situational awareness of the pilot heavily depends on the information provided by the S&A system and on the interface that gives him this information.







Figure 3-6 UAS mission requiring a satellite relay (BLOS)

3.2.4 2020 airspace classification

The 2020 airspace definition is one of the goals of the SESAR initiative.

The present situation shows that the preliminary idea is to consider two broad types of airspace, a so-called “managed airspace” (MA) and a so-called “unmanaged airspace” (UA).

The air traffic services that will be provided in MA have not been defined yet, they should be similar to the current class C or D airspace whereas the UA situation should be similar to current class G airspace.

3.3 Tentative UAS operational categorisation 3.3.1 Rationale

In the EUROCAE WG73 programme of work, a tentative UAS operation categorisation has been proposed in order to set a baseline for the functional requirements of any UAS to be flown in non segregated airspace.

These functions to be performed by a UAS depend on the desired UAS operation modes and their flying areas. It is based on the capabilities they have regarding separation and collision avoidance.

Consequently, this proposed categorisation does not call directly for specific equipment to be fitted in the UAS, either in the CS or in the vehicle, nor provides any requirement on the data link safety and security. It is only and simply based on capabilities regardless to the way they are obtained.







3.3.2 Proposed categorisation

This categorisation is as follows and is illustrated Figure 3-7.

ATCMBLOS

UASMBLOS

UASUASATCMBLOS

UASATCMBLOS

ATCMLOS

UASMLOS

UASUASATCMLOS

UASATCMLOS

UASMVLOS1

UASMVLOS2

ATCMBLOS ATCMBLOS

UASMBLOS UASMBLOS

UASUASATCMBLOS UASUASATC

UASUASATCMBLOS

UASATCMBLOS UASATCMBLOS

ATCMLOS ATCMLOS

UASMLOS UASMLOS

UASUASATCMLOS UASUASATC

UASUASATCMLOS

UASATCMLOS UASATCMLOS

UASMVLOS1 UASMVLOS1

UASMVLOS2 UASMVLOS2

Figure 3-7 Operational categories based on the UAS capabilities

• MVLOS: UAS mission enabling UAV/pilot visual contact • MLOS: UAS mission enabling LOS data links operations • MBLOS: UAS mission requiring a satellite as data links relay • ATC : Separation provided by ATC

• UASATC: Separation provided by UAS with traffic information from ATC • UAS : Separation provided by UAS on its own.

Category 1 UAS

In Category 1 using visual line of sight, the pilot has a direct visual contact with the UAS and all relevant air traffic from where a control station (CS) is located. This is a VFR operation only and other airspace classification requirements (such as communications, etc) must be met.

This can be expressed as follows: • Flight Rules : VFR; • Any Airspace except Class A or B; • S/A - Visual line of sight by UAS pilot against all other airspace users; • C2 = LOS.








Category 2 UAS

Category 2 involves the use of a chase aircraft. The pilot has visual contact with the UAS and all relevant air traffic from a chase aircraft where an airborne control station (ACS) has been installed. Additionally the chaser is used to enhance the visibility of the (small) UAV to other airspace users.

For ATM purposes, this is a formation flight as prescribed in ICAO Annex 2 para 3.1.8. This is a VFR or IFR operation and other airspace classification requirements (such as communications, etc) must be met. UAS placed in this category operate with radio communication being performed without any latency.

This can be expressed as follows: • VFR/IFR; • Any class of Airspace; • S/A - Visual line of sight by UAS pilot against all other airspace users and VMC

conditions, • C2 = LOS.

Category 3 UAS

The third category uses command and control (C2) link line of sight and communications line of sight between aircraft and control station. It is more demanding regarding some onboard functions as, for instance, the complicated sense and avoid problem. In such a system, the pilot gets information about the status of the aircraft and sends instruction through one or several C2 links. The link is also used to provide the information necessary for S&A. The maximum operation distance of the UAS from its CS is limited by the link light of sight capabilities.

In this category, the pilot has no visual contact with the UAS and its surrounding environment. The UAS will be expected to operate like a manned aircraft, with the pilot positioned on the ground.

Two cases have to be considered in this category as, regarding separation provision, a great difference exists between the airspace where ATC is in charge of the separation and the ones where this function may rely on the pilot (see Figure 3-1).

For the Cat 3A UAS, this can be expressed as follows: • VFR/IFR; • Classes A and B of Airspace5; • S/A - Collision avoidance with all other airspace users by the UAS; • C2 = LOS.

For the Cat 3B UAS, this can be expressed as follows: • VFR/IFR; • Classes C to G of Airspace1;

5 If S&A surveillance is only co-operative, access to airspace is a function of airspace transponder carriage requirements.







• S/A - Remote surveillance1 of all other airspace users by the UAS pilot; • C2 = LOS.

Category 4 UAS

The fourth category is more technically complex using a communications link through a relay system and is used beyond visual line of sight.

The UAS operates like a manned aircraft with the pilot on the ground, but transparency to the ATC is more difficult to achieve due to the latency of the link relay. This latency risks not permitting timely and conventional two-way RT exchanges. More importantly this latency delays the pilot’s ability to respond to ATC instructions. Moreover, the transmission of sense and avoid information will be delayed.

Two cases have to be considered in this category as, regarding separation provision, a great difference exists between the airspace where ATC is in charge of the separation and the ones where this function may rely on the pilot.

For the Cat 4A UAS, this can be expressed as follows: • VFR/IFR; • Classes A and B of Airspace1; • S/A - Collision avoidance with all other airspace users by the UAS; • C2 = BLOS.

For the Cat 4B UAS, this can be expressed as follows: • VFR/IFR; • Classes C to G of Airspace1; • S/A - Remote surveillance1 of all other airspace users by the UAS pilot; • C2 = BLOS.

Category 5 UAS

UAS placed in this category have full self separation provision and traffic avoidance capabilities. These capabilities can be either performed through a high level of autonomy and may or may not have a pilot. They are not required to contact ATC and their use is limited to classes E to G airspace.

This can be expressed as follows: • VFR; • Class E to G Airspace only; • S/A – Autonomous against all other airspace users; • C2 = Autonomous.

3.3.3 Comments on the proposed categorisation

This proposed categorisation has been set up as “incremental”, from a limited capability of the UAS to be integrated into the airspace (CAT1), to a full capability to be integrated in







all types of airspace (CAT4). The CAT5 has been added lately to cope with requirements of designing UAS having only the capability to fly in class G airspace.

• CAT 1 UAS have no full onboard S&A equipment. The separation and collision avoidance functions rely on a pilot who has a visual contact on the UAV and on its environment.

• CAT 2 UAS are more capable as they are able to process and comply with ATC instructions. Typically, the separation function is provided by ATC and the collision avoidance is provided by autonomous onboard equipment, but it must be assured that the chaser aircraft is not endangered by unexpected manoeuvres. Alternatively the chaser aircraft can warn surrounding traffic, such that collision avoidance is performed by them.

• CAT 3 UAS have an additional capability compared to CAT 2 UAS. They are able to separate when helped by ATC traffic information. Typically, the separation function is made by the UAVs that can steer their sensors toward the ATC announced traffic and the collision avoidance is provided by autonomous onboard equipment.

• CAT 4 UAS have an additional capability compared to CAT 3 UAS. They are able to separate without any help from outside the UAS system. Typically, the separation function is made by the UAV that has to “search the sky” for surrounding traffic and alter route accordingly. The collision avoidance is provided by autonomous onboard equipment.

• CAT 5 UAS category has been added to consider UAS that would be allowed to fly only in class G airspace. UAS of that category would not have to be fitted with equipment enabling ATC contact. Nevertheless, their S&A equipment should be very capable.

This operation categorization is mostly valid for the UAV cruise flight. Blending into airfield circuits and taxiing on airport will request complementary capabilities to be determined at a later stage of the categorisation setting process.

3.3.4 Systematic approach

Today’s airworthiness requirements are much more precise than those issued sixty years ago. Just as knowledge about aircraft has become something common, new technologies have been knocking on the door seeking to become incorporated within the existing systems. As the need to have something new became evident, certifying agencies have had to think about how these new things should be verified.

Starting from the need to make this subject easier to understand and to handle, aircraft and their related equipment were divided into several different types and categories. Their related requirements have been connected to these different categories. This simple connection eased the situation both for the designers and for the certifying agencies.

As it now appears, that unmanned aerial vehicles are close to entering civil operations, the need for certification has raised the question whether the same approach with different types and categories may help the designers and certifiers just as it did some decades ago for manned aviation.

Comparison of manned and unmanned operation







The overall target of ensuring safe operation of manned aircraft is met by different means which are focussed both on the aircraft and on the people on board. The underlying idea behind is, if the crew is well, they will operate the aircraft safely within its approved envelope. If so, this safe operation prevents danger to third parties in the air and on the ground.

In general, they only have to keep airspeed and attitude within the allowed limits, prevent collisions and navigate the aircraft from airport to airport.

For unmanned AC, the situation is quite different. In nearly every known UAV, the Flight Management System takes the responsibility for the right speed and attitude. But does the FMS have any information about the weather and its related phenomena? The crew is not on board and the current weather situation may be second-hand information. If now the gust loads are not to become excessive, this should be taken into account during the pre-design. But as there is no operating crew on board, nobody on board has to be protected from structural failure.

The integrity of a UAV is necessary in order to protect people and property on the ground.

As the crew of a manned aircraft is responsible for “see and avoid”, this problem becomes really hard to solve for a UAV. Every pilot has to undergo a medical test at different intervals of time. It depends on what kind of aircraft he is going to operate. Every test includes the eyes of the pilot. During his education, every student has to learn the procedures and their legal background in theory, and he learns how to carry out the manoeuvres in practice. Supplementary information either from ATC or from special equipment helps the crew to become clearly informed about their current situation.

Again, as there is nobody on board a UAV, the word “see” from the term “see and avoid” should be replaced by the word “sense” for UAVs. But if the UAV is operated together with manned AC, the capability of avoiding a mid-air collision must be assured in all cases.

The means of preventing mid-air collisions are intended to protect people on board other aircraft and, secondarily to protect third parties on the ground.

To sum up, the structural needs of UAVs and manned AC are almost similar; many automatic functions are to be seen in the same way, but the question of keeping the person responsible as reliably informed as if he or she were in the aircraft’s cockpit and to offer a safe and reliable possibility making the AC act some way other than programmed leads to the question about the “system” which replaces the man / machine system of manned aviation.

Leaving the aircraft, the remaining components of the system are the control station and the data link. As mentioned above, the data link or the data links are needed for the transmission of command and control data between control station and aerial vehicle, and if the airspace requires, for communication. It may be a “line-of-sight link” or a “beyond-line-of-sight link”.







These data links must be safe and secure, must permit the linkage between AC and CS for the desired operation, and should allow transfer of the required data at the necessary rate and with an acceptable delay. If we have to talk about “links” in a manned AC, one link may be seen between the pilot’s eyes and the panel. Another link may be identified between his or hers sensorial capabilities and special signals from the AC in different situations. Examples are the wobbling stick while approaching stall speed, or visible smoke inside or outside the cockpit. If we have to act with a communication link, in most cases the UAV will act as a relay between ATC / ATS and the control station. Things to remember when using some Relay for transmission are the possibility of becoming “blocked out” and the delay time between sending and receiving. The communication between manned aircraft and the ground or other aircraft will be direct in the case of normal operation. Relay communication will only be used if some station is out of range.

The control station itself should give the operator the possibility of becoming informed about any necessary status of the aerial vehicle. This requires situational awareness including the information about where and how the AC is. As techniques are moving forward, the display must not necessarily be a copy of a conventional cockpit with all the analogue dials of the past. The CS looks in many cases much more like an ATC working station with supplementary information about the aerial vehicle(s) which is or are currently under control. But control of a UAV implies command. Therefore the means of executing these commands have to be added. The same applies to communication devices.

The system

The UAV system is different by nature from a manned system. Certain functions and decisions which are normally carried out by the crew on board now have to be transferred to the system (i.e. the FMS), or to the control station – regardless of where its location will be during operation. The information between control station and the UAV is provided by data-link.

So the operating system which we have to talk about consists as a minimum of:

• The aerial vehicle • The control station • The data-link

To operate the UAV in the same way as to a manned aircraft, there is the need to have the following functionalities or subsystems:

The absence of the crew on board raises the need for a different set of possibilities to command the aircraft, and to control it. For this reason, the UAV needs a safe, secure and, if required, redundant command and control link to the control station.

As communication is a major factor for safety and a need within different classes of airspace, a UAV will need a safe communication link; if required, that link must be redundant. As there is nobody on board, the manoeuvres will be carried out by the flight control-system.

As everybody needs to know how and where to go, a navigation system will be necessary for UAVs too.







The existing emergency procedures are mostly published in the rules of the air, but they assume the presence of a pilot on board. A UAV therefore should have a qualified and accepted emergency system which is able to carry out its operation on the occurrence of any kind of system error or system failure without causing catastrophic accidents to third parties.

Depending on the weather conditions, a detection system, redundant if required, could be necessary.

The ability to make on-board decisions based on the collected data is nothing new for aviation, but as there is no pilot on board to make decisions, this will be done by a computer. In other cases it must be done by the operator. He needs to have the ability to command special functions from the control station, if the on-board intelligence is not sufficient to make the right decision (assessment of information or trouble-shooting). This feature includes the possibility of re-tasking the aircraft, command mission changes or safety/ emergency procedures, or flying the aircraft actively, in “real time” if requested (“real time capability”).

Also, with respect to human nature, the workload of the individual operator must be taken into account. As a direct function of the mission’s duration, a crew rotation after a certain time will be necessary, for example, like for the crew of an airliner flying long range or personnel in ATC centres.

As the number of UAV systems increases, so also do the national requirements for them and definitions regarding what a UAV will be. These requirements are mostly published by military agencies but airworthiness standards for the type inspection of military UAVs are often further developed than civil standards.

As airworthiness requirements for UAV systems are based only on a little experience and a wide range of uncertainty about what may occur, the focus here is set on safety factors. This uncertainty is reflected within the safety factors for nearly every case of a possible failure. This leads directly to an acceptable level of safety.

What does a “level of safety” mean for UAV systems within this context? The answer is: “To prevent hazard to third parties”, whether they are in the air or on the ground.

Development of civil categories for UAVs

Thinking about a hazard analysis may lead to the answer that more factors will influence the rate of hazard and should be identified.

In a first approach, factors for the possible hazard for third parties on the ground are: • The kinetic energy in the case of an impact

o Weight of the UAV o Speed of the UAV







• Damage or lethal area o Size of the UAV o Capability of reaching pre-selected crash sites or alternate airfields o On-board recovery system o Integrity of the AV in the case of an accident

Factors for the possible hazard for third parties in the air are: • Capabilities of the AV

o Speed o Type of data-link o Collision avoidance equipment

• Flight rules and weather conditions

o ATC / ATS o Related equipment

3.4 UAS ATM concept, from the current situation to 2020

Due to the problems encountered to solve the sense an avoid issue and provide an acceptable level of safety for the UAS flights in non segregated airspace, all current systems are only CAT1.

Regarding the “CAT2 like” systems, a current procedure that can be used by controllers is to arrange a local a temporary segregated airspace around the UAV (High altitude flight of the Global Hawk where no other traffic can be encountered).

In the following sections of this document, UAS possible functional architectures will be detailed according to their category. The difficulty to be faced to define these architectures is linked to the unknown shape of the 2020 ATM.

Two broad types of hypothesis will be considered in the document:

• A slow evolution of the ATM without any mandate to make all flying vehicles cooperative and relying on an ATC still based on voice messages;

• An advanced ATM with a mandate for cooperative flying vehicles and a more digital ATM system.

The functional architecture of the UAS will depend on its category and on the ATM evolution hypothesis.

3.5 UAS Functional Architecture: High-Level Functions (HLF) and sub-functions

Although the detailed functional architecture of the UAS is dependant on the UAS category (as mentioned in the previous section), a set of high-level functions can be defined as applicable for any UAS to operate in the SES (and in many cases even applicable to UAS operating outside the SES), which constitute the focus of interest of the INOUI project.






Therefore, the functional architecture presented hereafter is intended to be as generic as possible, while capturing the significant functions necessary for safe flight of any UAS. However, no single functional decomposition is suitable for the wide variation in UAS types and operations. Hence, the functional decomposition here presented is rather applicable to those UAS more similar to conventional transport or general aviation aircraft.

The functional architecture is built using a simple tree structure is used to represent the basic relationship between the functions.

It must be reminded that a function:

• Refers to a specific action or number of actions. • Must include a complete operational capability, that is, it must be observable at the

operational level. • Includes its interface (human or machine).

The functions hereafter described are based on the work developed by the Access 5 programme, in particular: the Functional Requirements Document for HALE UAS operations in the US airspace (NAS) [6] and a preliminary FHA for UAS [7]. Figure 3-8 presents these high-level functions (HLF).

UAS

HLF-1Aviate

HLF-2 Navigate

HLF-3Communicate

HLF-4Mitigate

CNS

Figure 3-8 UAS High Level Functions (HLF)

In Figure 3-8 it is remarked the fact that high-level functions ‘Communicate’ (HLF-3), ‘Navigate’ (HLF-2), and partially ‘Mitigate’ (HLF-4), correspond to the CNS (Communication-Navigation-Surveillance) functional block, traditionally considered as one of the fundamental blocks in the airborne part of the CNS/ATM functional architecture. With regard to the Surveillance function, it is addressed by the ‘Mitigate’ function, which also includes other functionalities, as it is depicted in Figure 3-12.

It must be also noted that most functions (and related sub-functions) are not independent but inter-related, as in many cases a function requires the participation of other(s) in order to be performed.

3.5.1 HLF-1: ‘Aviate’

‘Aviate’ includes those actions necessary for:







• Flying the aircraft, that is: o Provision of flight forces: lift and thrust o Provision of the appropriate level of stability in the air o Provision of control of the aircraft in the air: control flight path (FP) / attitude

• Moving the aircraft on the ground, that is: o Provision of ground forces: thrust, braking force, drag o Provision of the appropriate level of stability on the ground o Provision of control of the aircraft on the ground: control ground path (GP)

• Providing command and control (C2) of the aircraft from the Control Station • Managing aircraft sub-systems • Providing structural integrity

This high level function is broken down into lower level functions and sub-functions, as depicted in Figure 3-9.

HLF-1Aviate

ControlAir-Ground

Transition (AGT)

ControlGround Path

(GP)

ControlFlight Path (FP) /

AttitudeCommand & Control UAS

Control UAS Subsystems &

Stability

Provide Lift

Provide Thrust

ProduceFP/Att. Command

ExecuteFP/Att. Command

Convey FP/Att. Command Status

Convey GP State

DetermineGround intent

ProduceGP Command

ExecuteGP Command

Convey GP Command Status

Convey AGT State

DetermineAGT intent

ProduceAGT Command

ExecuteAGT Command

Convey AGT Command Status

Maintain C2 during all phases of flight

Secure C2 during all phases of flight

Prioritize C2 data

Control Power Subsystems

Control Fire Suppr. Subsystem

Provide UAS Stability

Control internal UAS environment

Monitor & Record UAS state data

ProvideFlight Forces &

Stability

Convey FP / Attitude State

DetermineGuidance Command

ProvideStructural Integrity

Figure 3-9. UAS HLF-1: ‘Aviate’

3.5.1.1 Provide Flight Forces and Stability

This sub-function involves:

• Generation and control of the forces required for flying the aircraft, including:

o Provide Lift: Generate and control lift to counteract, as required, the aircraft weight, and enable manoeuvres in the air.

o Provide Thrust: Generate and control thrust to counteract, as required, the aircraft drag in flight.

• Provision of the required level of stability for flying the aircraft. This task includes controlling the CG to keep aircraft’s level of stability and performance within aircraft’s envelope.








3.5.1.2 Maintain Structural Integrity

The aircraft is required to provide a continuous structural integrity in order to ensure the safety of operations (air and ground operations).

3.5.1.3 Control Flight Path (FP) /Attitude

This sub-function involves controlling the flight path (FP) of the aircraft and/or the aircraft attitude (FP usually involves attitude changes, but there may be situations where the attitude, e.g. pitch, may vary following the same path). The following tasks are included within this sub-function:

• Convey FP/Attitude State: Sense, communicate and display (when applicable), current state of FP and/or attitude.

• Determine Guidance Command: Gather and select the appropriate high-level command(s) for aircraft guidance in flight.

• Produce FP/Attitude Command: Translate the high-level FP/Attitude command(s) into the corresponding low-level FP/Attitude command(s). E.g. for a traditional flight control system, high-level attitude commands are translated into low-level flight control surface commands.

• Execute FP/Attitude Command: Execute the low-level FP/Attitude command(s) for physically manoeuvring the aircraft in the air.

• Convey FP/Attitude Status: Provide the operator and/or some diagnostic system with the information on the possible difference between the FP/Attitude command(s) and its (or their) execution.

3.5.1.4 Control Ground Path (GP)

This sub-function involves controlling the ground path (GP) of the aircraft. The tasks included within this sub-function are equivalent to those of the Control Flight Path (FP) / Attitude, namely:

• Convey GP State: Sense, communicate and display (when applicable) the condition of current GP state.

• Determine Ground intend: Gather and select the appropriate high-level command(s) for aircraft guidance on the ground.

• Produce GP Command: Translate the high-level GP command(s) into the corresponding low-level GP command(s).

• Execute GP Command: Execute the low-level GP command(s) for physically manoeuvring the aircraft on the ground.

• Convey GP Status: Provide the operator and/or some diagnostic system with the information on the possible difference between the GP command(s) and its (or their) execution.







3.5.1.5 Control Air/Ground Transition (AGT)

This sub-function involves controlling the transition from:

• Ground to air, referring to the part of the flight initiation phase when the aircraft gets airborne, which excludes the control of the aircraft on the ground, e.g. taxi to the runway / take-off platform (taxi corresponds to the ‘control GP’ sub-function). In addition to take off from runway/platform there are other ways to initiate flight and perform the corresponding transition, e.g. being catapulted, being dropped from another aircraft, being launched from a rocket, …

• Air to ground, referring to the part of the flight finalisation phase until the aircraft reaches the ground or it is trapped (e.g. by using a net), and excluding the control of the aircraft on the ground, e.g. taxi from the runway / landing platform to the parking area (taxi corresponds to the ‘control GP’ sub-function). There are different ways to carry out a flight finalisation, e.g. landing with undercarriage, landing with skids, using a parachute, using a net, … It must be noted that the case of flight termination due to the impossibility of continuing the flight safely is deemed to be included in the ‘Mitigate’ high-level function.

The tasks included within this sub-function are equivalent to those of the ‘Control Flight Path (FP) / Attitude’ and ‘Control Ground Path’, namely:

• Convey AGT State: Sense, communicate and display (when applicable), current state of current AGT state (e.g. height above terrain, weight on wheels, …).

• Determine AGT intend: Gather and select the appropriate high-level command for aircraft air-ground transition.

• Produce AGT Command: Translate the high-level AGT command(s) into the corresponding low-level AGT command(s).

• Execute AGT Command: Execute the low-level AGT command(s) for physically manoeuvring the aircraft or activating/deactivating devices (e.g. deployment/retraction of flaps/slats) enabling the transition from ground-to-air or from air-to-ground.

• Convey AGT Status. Provide the operator and/or some diagnostic system with the information on the possible difference between the AGT command(s) and its (or their) execution.

3.5.1.6 Command & Control (C2) the UAS

This sub-function corresponds to the transmission of signals from the Control Station to the aircraft via data link to command and control (C2) the aircraft.

The tasks included within this sub-function are:

• Maintain C2 during all phases of flight: Ensure the link between the Control Station and the aircraft during the whole flight, from its initiation to its finalisation.







• Secure C2 during all phases of flight: Prevent unauthorised access to the C2 data link during the whole flight.

• Prioritise C2 data: Select the right order of transmitting and processing C2 data to perform the appropriate command/ control action.

3.5.1.7 Control UAS Sub-systems and Stability

This sub-function refers to the control of UAS sub-systems others than those conceived to directly carry out the ‘Aviate’ function (e.g. flight controls, lift and propulsion provision, …), and the control of aircraft stability. In particular, this sub-function includes:

• Control Power subsystems: Control the generation and distribution of electrical, hydraulic and pneumatic (if applicable) power.

• Control Fire Suppression subsystem: Control the subsystem that would help suppressing any fire initiated in the UAS.

• Control Internal UAS Environment: Control all parameters related to internal UAS environment that could affect UAS sub-systems functioning and performance (e.g. temperature, etc.)

• Monitor & Record UAS state data: Monitor and record all parameters deemed relevant to performance, reliability and safe operation of UAS sub-systems.

3.5.2 HLF-2: ‘Navigate’

‘Navigate’ includes those actions necessary for:

• Developing and updating Flight Plan • Identifying current position • Determining how to transition to destination • Producing, executing, and conveying navigational commands

As mentioned before, the high level functions (HLFs) described in this chapter are dependant on each other. In the case of Navigation, it is especially relevant the link between this function and the ‘Collision Avoidance’ function. In fact, some authors consider the problem of navigation as a twofold problem:

1. Global problem: Route Planning, based on: • Current Position • Final goal(s) (mission target(s), final destination) • All relevant information about environment throughout the mission.

2. Local problem: Collision Avoidance: • Current Position • Immediate environment • Vehicle capability






• Near term goal (in the next few seconds)

However, it is a common understanding now that collision avoidance is not viable to organize the traffic and separation provision is the function to be considered in the navigation. The environment is local and not immediate. Thus it has been deemed more appropriate to consider the global problem as the ‘Navigate’ HLF, and the local problem as a function within the ‘Mitigate’ HLF. Accordingly the collision avoidance is considered in the ‘Mitigate’ HLF (see 3.5.4 further down).


HLF-2Navigate

ProduceNavigation Command

DetermineNavigation intent

Convey Navigation state

DetermineNavigation

Command status

DetermineMission/Flight Plan

Determine long-next required separation

DetermineRight-of-Way proc.

Figure 3-10 UAS HLF-2: ‘Navigate’

3.5.2.1 Convey Navigation state

This sub-function involves sensing, communicating and displaying (when applicable), current state of Navigation parameters, e.g. position (latitude, longitude, altitude), etc.

3.5.2.2 Determine Navigation intent

This sub-function refers to gathering and selecting the appropriate information to produce the required high-level command for navigational purposes. The tasks included within this sub-function are:

• Determine Mission/Flight Plan: Gather and select the appropriate information to determine the mission/flight plan, at strategic level, and next waypoint, at tactical level.

• Determine long-next required separation: Gather and select the appropriate information to determine long-next (strategic level) required separation with respect other traffics.

• Determine ‘right of way’ procedure: Gather and select the required information to determine the appropriate procedure to follow the ‘right of way’ rule.







3.5.2.3 Produce Navigation command

This sub-function addresses the translation of the high-level navigation command(s) into the corresponding low-level navigation command(s).

3.5.2.4 Determine Navigation command status

This sub-function involves providing the operator and/or some diagnostic system with the information on the possible difference between the navigation command(s) and its (or their) execution.

3.5.3 HLF-3: ‘Communicate’

‘Communicate’ includes those actions necessary for communicating with ATC and other airspace users.


HLF-3Communicate

Transmit Infoto ATC &

other A/Cs

Transmit Communications

Broadcast Transponder Data

Participate in lost C2 Link Procedures

Receive Infofrom ATC &other A/Cs

Receive Communications

Receive Transponder Data

Monitor Comms from ATC & A/Cs

Figure 3-11 UAS HLF-3: ‘Communicate’

3.5.3.1 Transmit information to ATC and other aircrafts

This sub-function involves the transmission or broadcasting of information to the Air Traffic Control (ATC) and/or other airspace users (i.e. manned or unmanned aircrafts)








3.5.3.2 Receive information from ATC and other aircrafts

This sub-function involves the reception of information from the Air Traffic Control (ATC) and/or other airspace users (i.e. manned or unmanned aircrafts)

3.5.4 HLF-4: ‘Mitigate’

‘Mitigate’ includes those actions necessary for:

• Avoiding collisions with air traffic, terrain or obstacles on the ground • Avoiding adverse meteorological conditions • Managing any contingency in the UAS (aircraft and/or control station)

This function is not typically included as a top-level aircraft function in manned aviation. However it is deemed to be important including this function at this high level, as safety, which is paramount in aviation, concerns even more when referring to unmanned aviation, and it is likely that some or most of the mitigation actions will be performed by automation within the UAS.







HLF-4Mitigate

Manage Contingencies

Avoid Adverse Environmental

ConditionsAvoid Collisions

Avoid terrain & vertical structures

(while airborne)

Avoid Air Traffic

Avoid GP obstacles (while landing / on-

ground)

Detect adverse environmental

conditions

Track relative location of adverse

environmental cond.

Convey relative location of adverse

environmental cond.

Determine corrective action

Determine corrective action

Produce corrective action command

Execute corrective action command

(by ‘Aviate’)

Convey post corrective action

status to ATC

Convey system status

DetermineContingency

command

ProduceContingency

command

PrioritiseContingency

command

ConveyContingency

commands status

Figure 3-12 UAS HLF-4: ‘Mitigate’

3.5.4.1 Avoid collisions

Within this sub-function the following mitigation actions can be considered:

• Avoid air traffic: This functionality implies performing the following chain of actions:

• Detect air traffic • Track air traffic • Provide air traffic tracks • Determine corrective action • Select corrective action command • Execute corrective action command (accomplished by the ‘Aviate’ function) • Convey post corrective action status to ATC








• Avoid terrain and vertical structures on the ground (while aircraft is airborne): This functionality implies performing the following chain of actions:

• Detect terrain and vertical structures on the ground • Track relative location of terrain and vertical structures on the ground • Provide relative location terrain and vertical structures on the ground • Determine corrective action • Produce corrective action command • Execute corrective action command (accomplished by the ‘Aviate’ function) • Convey post corrective action status to ATC

• Avoid ground path (GP) obstacles (while landing or on ground):

This functionality implies performing the following chain of actions:

• Detect ground path obstacles • Track relative location of ground path (GP) obstacles • Provide relative location of ground path (GP) obstacles • Determine corrective action • Produce corrective action command • Execute corrective action command (accomplished by the ‘Aviate’ function) • Convey post corrective action status to ATC

3.5.4.2 Avoid adverse environmental conditions

This sub-function involves the following chain of actions, analogous to those mentioned for collision avoidance:

o Detect adverse environmental conditions o Track relative location of adverse environmental conditions o Convey relative location of adverse environmental conditions o Determine corrective action o Produce corrective action command o Execute corrective action command (accomplished by the ‘Aviate’ function) o Convey post corrective action status to ATC

3.5.4.3 Manage contingencies

This sub-function refers to the management of any contingency within the UAS (aircraft and/or control station) by the operator or automation. The tasks included within this sub-function are:

• Convey system status: Gather information about the state of the UAS related to contingencies (e.g. communication status).

• Determine contingency command: Assess the system to determine what contingencies have occurred, what could be the consequences and what other contingencies could occur. As there might be multiple failures, and predictions of







potential failures might be difficult, the contingencies assessment may be a complex task. Based on this assessment, high-level command(s) to mitigate the contingency has to be determined.

• Produce contingency command: Decide which actions should be taken to respond to contingencies.

• Prioritise contingency command: Establish priorities among the different commands that might have been produced to respond to the different contingencies that might be occurring, according to their severity and urgency.

• Convey contingency commands status: Inform the operator and/or automatic system on the contingency commands that have been taken.

It must be noted that the execution of contingency commands would be performed by means of any of the other HLF.







4 Conclusions The objective of WP 1.1 of the INOUI project is the identification of the future Air Traffic Management (ATM) environment expected in the 2020 timeframe which sets the operational scenario for UAS integration.

From ATM perspective, future UAS operations will pose a unique set of issues. First, because UAS designs and capabilities will vary widely, their performance characteristics will differ significantly from those of manned aircraft. UAVs will range in size and flying capabilities - from several 100 g to thousands of kg, and from slow ones with bad manoeuvrability to fast and agile ones. Some UAVs will be launched and recovered from virtually any location. Additionally, sophistication will vary among vehicles, from those having fully autonomous flight controls to those requiring more direct pilot inputs. Communication systems will range from those capable of global reach to those limited to line of sight. Further, the types of missions being planned for UASs of the future are rarely point to point but typically involve some form of patterned flight or tracking activity that may include intermittent short- or long-term orbits. Endurance will last from hours to months, depending on the vehicle and mission. Taken together, these variations have the potential to significantly affect air traffic operations and will place additional challenges on an ATM system already under great strain, although the ATM system of the future will be better equipped to manage the additional complexity related to the rise of UASs.

The ATM system is a network of communication, navigation, and surveillance systems that ensures safe, orderly and efficient flight. Driven by the SES programme and SESAR the European ATM is expected to change significantly over the next years with the introduction of new technologies and procedures. Many of these changes will be motivated by increasing demand in the number and diversity of system users, including the addition of UAS.

Based on the available information of SESAR, the Concept of Operations and other inputs the following broad assumptions regarding the future ATM and UAS characteristics are drawn that are establishing the foundation for the future ATM and routine access of UAS into civil airspace.

In the future ATM, a System Wide Information Management (SWIM) will aggregate, integrate, fuse, and disseminate tailored information to both air traffic service users (pilots, airlines, military, etc.) and providers (ATC, meteorologist, traffic flow managers). The system will provide common situational awareness if the location and intent of other aircraft is known, facilitate collaboration, and link systems and users together for effective decision making. UAS operators will be both consumers and providers of this information.

The future ATM will focus on 4-D trajectories. By using a 4-D flight plan, each flight will navigate at selected latitude, longitude, and altitude (similar to the current system), as well as self delivering to a time tolerance at a series of4-D waypoints. 4-D flight plans will reduce uncertainty and increase predictably for both air traffic service users and providers. Although most UASs will be equipped with a GNSS based or other approved navigation system, only the more sophisticated UAS will be able to take advantage of the 4-D option because of the stringent certification requirements for 4-D flight. Those UASs and manned aircraft unable to meet the 4-D criteria will instead file 3-D flight plans. Other non-trajectory







defined flight plans will also be allowed for operations where exact routes or altitudes cannot be predetermined.

Communications between operators of both manned and unmanned aircraft and the ATM system will be increasingly relying on electronic data exchanges via datalink for routine communications. These exchanges will require the operators' acknowledgment and approval prior to execution of the air traffic instruction. Depending on the aircraft, these instructions may automatically feed into the flight control systems, whereas in other vehicles, manual control actions will still be required. However it is very likely that voice remains an essential means of communication at least until the 2020 timeframe using standard equipment and frequencies of today. Especially in time critical events, datalink applications have not proven to be a substitute to voice. Beyond 2020, and as defined by the SESAR Concept of Operations, voice will remain the primary means of communications only in certain circumstances. The role of voice communications will then essentially be a safety back-up means.

The ATM will strategically adjust ATC sector boundaries to increase flexibility in the provision of air traffic services. The air traffic system will employ this strategy to distribute workload more evenly when demand for services is expected to exceed the sector capacity. These actions will be transparent to the operators of manned and unmanned aircraft.

Alternative separation methods will be provided, with separation responsibility delegated to pilots for limited durations, when and where appropriate. This will mitigate controller workload and improve the efficiency of operations. Also new airborne separation and delegation procedures and corresponding technologies will provide a concept that could allow UAS to safely separate themselves from other aircraft: However it must be noted in manned aviation the final responsibility for collision avoidance remains at the pilot side. In uncontrolled airspace and under VFR, where the technical requirements for navigation and surveillance equipment are reduced compared to IFR and controlled airspace the collision avoidance is referred to as “see-and-avoid” principle. For UAS this principle is not applicable to its full extend but rather referred to as “sense-and-avoid” principle, which is one of the major challenges for UAS integration.

A certain number of UASs will be operated exclusively by a remote pilot without assistance from any type of automation. But also some UASs operating in the future ATM will possess a range of autonomous capabilities to perform or assist in navigation, system monitoring, and flight control functions.

UAS will have various levels of equipage for interacting with the air traffic system, e.g. transponders (Mode-S, ADS-B) and 4-D navigation system. Equipage levels will be determined by limitations in size, power generation, and payload capacities of the vehicle, furthermore vehicle cost and mission needs.

Safety and security classifications, approvals and controls will be required for all civil and commercial UAS operations. For example, all UAS will have certified and approved plans for lost communication links and system failures. Datalink communications for vehicle control and flight telemetry will be encrypted to safeguard the protection of the data link, the authenticity of the operator and the correctness of data transfer and processing.







Taken together, these assumptions indicate that different new technologies and procedures have to be developed and applied within the future ATM system to enable the integration of UAS into the airspace. On the other hand technologies developed for and by the UAS community could also bring benefit to the future ATM and manned aircraft.







5 Annex A: Definitions Table 5-1 contains definitions used throughout the INOUI project.

Table 5-1 Definitions used in INOUI

TERMINOLOGY ACRONYM DEFINITION REF.Adequate Alternate Aerodrome

An adequate alternate aerodrome is one at which the landing performance requirements can be met and which is expected to be available, if required, and which has the necessary facilities and services, such as air traffic control, lighting, communications, meteorological services, navigation aids, rescue and fire-fighting services and one suitable instrument approach procedure.

[8]

Advisory A message that serves to warn the controller of actual or anticipated actions that are required to bring a flight back to plan. Advisories are of the following type: time, speed, direction or, holding information.

[10]

Advisory airspace An airspace of defined dimensions, or designated route (also: advisory route), within which air traffic advisory service is available.

[8]

Aerodrome A defined area on land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft.

[8]

Aeronautical Information Service

AIS A service established within the defined area of coverage responsible for the provision of aeronautical informationldata necessary for the safety, regularity and efficiency of air navigation.

[8]

Aeronautical Mobile Service

AMS A mobile service between aeronautical stations and aircraft stations, or between aircraft stations, in which survival craft stations may participate; emergency position-indicating radio beacon stations may also participate in this service on designated distress and emergency frequencies.

[8]







TERMINOLOGY ACRONYM DEFINITION REF.Air Navigation Service

ANS A generic term describing the totality of services provided in order to ensure the safety, regularity and efficiency of international air navigation and the appropriate functioning of the air navigation system.

[10]

Air Navigation Service Provider

ANSP An organisation responsible for providing Air Navigation Service.

An organisation that provides the service of managing the aircraft in flight or on the manoeuvring area of an aerodrome vested in it and which is the legitimate holder of that responsibility.

[10]

Air Navigation System

The aggregate of organisations, people, infrastructure, equipment, procedures, rules and information used to provide to Airspace Users Air Navigation Services in order to ensure the safety, regularity and efficiency of international air navigation.

[10]

Air traffic All aircraft in flight or operating on the manoeuvring area of an aerodrome.

[8]

Air Traffic Advisory Service

A service provided for the purpose of: a) preventing collisions: 1) between aircraft, and 2) on the manoeuvring area between aircraft and obstructions, and b) expediting and maintaining an orderly flow of air traffic.

[8]

Air Traffic Control Clearance

(ATC clearance)

Authorization for an aircraft to proceed under conditions specified by an air traffic control unit. Note 1: For convenience, the term “air traffic control clearance” is frequently abbreviated to “clearance” when used in appropriate contexts. Note 2: The abbreviated term “clearance” may be prefixed by the words “taxi”, “take-off”, “departure”, “en route”, “approach” or “landing” to indicate the particular portion of flight to which the air traffic control clearance relates.

[8]

Air Traffic Control ATC A service operated by appropriate authority to promote the safe, orderly, and expeditious flow of air traffic.

[10]

Air Traffic Control Unit

(ATC Unit) A generic term meaning variously, area control centre, approach control unit or aerodrome control tower.

[8]







TERMINOLOGY ACRONYM DEFINITION REF.Air Traffic Controller ATCO Usually meant to indicate the radar (executive)

controller. The person having final responsibility in co-ordinating traffic in a sector. The radar controller (often simply called the controller) is assisted by a planner (advance planning) and assistant.

[10]

Air Traffic Management

ATM The aggregation of the airborne functions and ground-based functions (air traffic services, airspace management and air traffic flow management) required to ensure the safe and efficient movement of aircraft during all phases of operations.

[8]

The dynamic, integrated management of air traffic and airspace — safely, economically and efficiently — through the provision of facilities and seamless services in collaboration with all parties.

[9]

Air Traffic Management System

(ATM System)

A system that provides ATM through the collaborative integration of humans, information, technology, facilities and services, supported by air and ground- and/or space-based communications, navigation and surveillance.

[9]

Air Traffic Management Community

(ATM Community)

The aggregate of organizations, agencies or entities that may participate, collaborate and cooperate in the planning, development, use, regulation, operation and maintenance of the ATM system.

[9]

Air Traffic Management Operational Concept

(ATM Operational Concept)

High-level description of the ATM services necessary to accommodate traffic at a given time horizon; a description of the anticipated level of performance required from, and the interaction between, the ATM services, as well as the objects they affect; and a description of the information to be provided to agents in the ATM system and how that information is to be used for operational purposes. The operational concept is neither a description of the air navigation infrastructure nor a technical system description nor a detailed description of how a particular functionality or technology could be used.

[9]







TERMINOLOGY ACRONYM DEFINITION REF.Air Traffic Service ATS A generic term meaning variously, flight

information service, alerting service, air traffic advisory service, air traffic control service (area control service, approach control service or aerodrome control service).

[8]

Air Traffic Service Airspace (Class A to G)

(ATS Airspace)

Are airspaces of defined dimensions, alphabetically designated, within which specific types of flights may operate and for which Air Traffic Services and rules of operations are specified

[10]

Air Traffic Services Unit

(ATS Unit) A generic term meaning variously, air traffic control unit, flight information centre or air traffic services reporting office.

[8]

Airborne Collision Avoidance System

ACAS An aircraft system based on secondary surveillance radar (SSR) transponder signals, which operates independently of ground-based equipment to provide advice to the pilot on potential conflicting aircraft that are equipped with SSR transponders.

[8]

Aircraft A/C Any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the earth’s surface.

[8]

Aircraft Address A unique combination of 24 bits available for permanent assignment to an aircraft for the purpose of air-ground CNS. Note : The aircraft address is also referred to as the Mode S address or the aircraft Mode S address in the context of SSR Mode S.

[10]

Aircraft Avionics A term designating any electronic device - including its electrical part - for use in an aircraft, including radio, automatic flight control and instrument systems.

[8]

Airspace Any portion of the atmosphere sustaining aircraft flight and which has defined boundaries and specified dimensions. Airspace may be classified as to the specific types of flight allowed, rules of operation, and restrictions in accordance with ICAO standards or State regulation (see ATS airspace).

[12]

Airworthiness The property of a particular air system configuration to safely attain, sustain, and terminate flight in accordance with the approved usage and limits

[15]







TERMINOLOGY ACRONYM DEFINITION REF. The condition in which the UAS conforms to its

type certificate and is in condition for safe operation.

[12]

An aircraft is deemed to be airworthy within EU if it meets or exceeds the essential requirements as defined in the EASA basic Regulation (EC1592/2002 Annex 1)

[11]

Airworthiness Certification

A repeatable process implemented to verify that a specific air vehicle system can be, or has been, safely maintained and operated within its described flight envelope. The two necessary conditions for issuance and maintenance of an airworthiness certificate are: 1) The aircraft must conform to its type design as documented on its type certificate, and 2) The aircraft must be in a condition for safe operation.

[15]

Automatic Dependent Surveillance

ADS A surveillance technique in which aircraft automatically provide, via a data link, data derived from on-board navigation and position fixing systems, including aircraft identification, four dimensional position and additional data as appropriate.

[8]

Autonomy The ability to execute processes or missions using on-board decision capabilities.

[11]

Aviate To operate an aircraft in the airspace. Aviating includes both controlling and monitoring the aircraft and all of its systems necessary for launch, climb, manoeuvre, cruise, descent, and recovery.

[12]

Beyond Line of Sight

BLOS [Referred to UAS] Distance beyond the electronic line of sight.

[12]

Broadcast A transmission of information relating to air navigation that is not addressed to a specific station or stations.

[8]

Collision avoidance CA Averting physical contact between an aircraft and any other object or terrain.

[12]







TERMINOLOGY ACRONYM DEFINITION REF.Communicate To inform others or to be informed.

Communicating is both the conveying of intent, and the receiving of instructions. (Note: This refers to voice communication and transponder like operations - it does not encompass command/control of the UA)

[12]

Communications, Navigation, and Surveillance

CNS The way in which enhanced capabilities of satellite-based navigation and digital data link communication systems will permit the next generation of ATM systems to combine the features of ADS and Controller-to-Pilot Data Link Capability with the conventional ATC functions. The combination of these enabling CNS technologies and their application to ATM has become known as CNS / ATM.

[10]

Concept of Operations

CONOPS A plan describing how to achieve a goal. Note: Not to be confused with an operational concept, which is the desired goal.

[12]

Control link The combination of the telecommand link (uplink) and the status telemetry link (downlink).

[12]

Control Station CS [Referred to UAS] The equipment used to maintain control, communicate, guide, or otherwise pilot an unmanned aircraft.

[12]

A facility or device(s) from which an unmanned aircraft is controlled for all phases of flight. There may be more than one control station as part of a UAS. Note: Usually a control station is located on ground, and then it is denominated Ground Control Station (GCS)

([11])

Controlled airspace An airspace of defined dimensions within which air traffic control service is provided in accordance with the airspace classification.

[8]

Cooperative traffic Traffic that broadcast position or other information that assists in detecting and assessing conflict potential. Cooperative traffic is typically equipped with a transponder.

[12]

Data link [Referred to UAS] A term referring to all links between the aircraft the control station. It includes that command, status, communications, and payload links.

[12]

Direct visual control

The means by which the UAS is controlled and the pilot exercises see and avoid responsibilities.

[12]







TERMINOLOGY ACRONYM DEFINITION REF.Emergency Recovery Procedures

Procedures that are implemented through UAS pilot command or through autonomous design means in order to mitigate the effects of certain failures with the intent of minimizing the risk to third parties. This may include automatic pre-programmed course of action to reach safe landing or crash area.

([11])

Equivalent Level of Safety

ELOS An evaluation, often subjective, of a system and/or operation to determine the acceptable risk to people and property.

[12]

Field of Regard FOR The range through which a sensor is able to be directed. Alternatively, the field over which objects may be viewed with a sensor system. Contrast with Field of View, which refers to the instantaneous area of view of a sensor.

[12]

Flight Management Control System

FMCS [Referred to UAS] An operable system that is contained onboard a UA that performs the flight control actions from input received from the pilot via the command and control communication link or that operates the UA from data previously inserted. This system does not require any additional pilot intervention.

[12]

Flight plan FPL Specified information provided to air traffic services units, relative to an intended flight or portion of a flight of an aircraft.

[8]

Flight Termination Procedure or function that aims to immediately end the flight.

([11])

Flight Termination System

FTS System enabling the flight termination

Gate-to-Gate A concept where the air traffic operations of ATM community members are such that the successive planning and operational phases of their processes are managed and can be achieved in a seamless and coherent way.

[9]

General Air Traffic GAT All flights conducted in accordance with the rules and procedures of ICAO. Note: These may include any flight of a State aircraft (see definition), if it flies in accordance with the procedures of ICAO.

[10]

Ground Control Station

GCS See Control Station







TERMINOLOGY ACRONYM DEFINITION REF.Instrument Flight Rules

IFR Rules governing the procedures for conducting instrument flight. Also a term used by pilots and controllers to indicate type of flight plan.

[12]

Instrument Meteorological Conditions

IMC Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling, less than the minima specified for visual meteorological conditions.

[8]

Interoperability The ability to exchange data or services between systems.

[12]

Latency The time incurred between two particular interfaces. The total latency is the delay between the true time of applicability of a measurement and the time that the measurement is reported at a particular interface (the latter minus the former).

[12]

Line-of-Sight LOS The condition where two systems, usually the control station and the UA, are within electronic point-to-point link.

[12]

Loiter To remain within a given volume of airspace. [12]

Manned aircraft Aircraft piloted by a human onboard. [12]

Navigate The directing of the aircrafts flight path to a desired location. [Referred to UAS] The ability to navigate infers the UAS is capable of maintaining navigational control, which involves maintaining knowledge of the current position, the destination, and the four dimensional path (latitude, longitude, altitude, time) to the destination.

[12]

Non-cooperative traffic

Traffic that does not broadcast position or other information that assists in detecting and assessing conflict potential. Non-cooperative traffic is typically not equipped with a transponder.

[12]

Non-segregated airspace

Airspace available for use by all aircraft.

Notice to Airmen NOTAM A notice distributed by means of telecommunication containing information concerning the establishment, condition or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations.

[8]







TERMINOLOGY ACRONYM DEFINITION REF.Operational Air Traffic

OAT All flights which do not comply with the provisions stated for GAT and for which rules and procedures have been specified by appropriate national authorities

[5]

Operational concept

[Referred to UAS] A high level description of ATM services necessary to integrate ROA into the NAS by a given time horizon.

[12]

Operational control With respect to a flight, means the exercise of authority over initiating, conducting, or terminating a flight.

[12]

Optionally Piloted Aircraft

OPA Aircraft that may be operated with or without an onboard pilot

[12]

Payload PL [Referred to UAS] The payload comprises all elements of the UA that are not necessary for flight but are carried for the purpose of fulfilling specific mission objectives.

[12]

Performance Requirements

Set of requirements that define a function’s performance, and expressed by a set of characteristics/attributes associated to all or part of a system. Those include transaction and expiration times, continuity, availability, and integrity characteristics

[12]

Phases of flight A distinct stage of flight which includes take-off, climb, en route, mission operations, descent, approach, landing

[12]

Phases of operation

A distinct stage of operation which includes: preflight ground operations, all flight phases, and post flight ground operations.

[12]

Qualification 1) Formal document or proof which recognises that a person has completed a specialised course of study and a particular skill. 2) The process of demonstrating whether an entity is capable of fulfilling specified requirements.

[10]

Process through which a State/approval authority/applicant ensures that a specific implementation satisfies applicable requirements with a level of confidence.

[12]

Reduced Vertical Separation Minimum

RVSM A reduction of the Vertical Separation Minima (VSM) above Flight Level 290 from 2,000 to 1,000 feet.

([10])







TERMINOLOGY ACRONYM DEFINITION REF.Required Communication Performance

RCP RCP is a statement of the communication performance necessary for operation within in a defined airspace.

[12]

Required Navigation Performance

RNP A statement of the navigation performance necessary for operation within a defined airspace.

[8]

A statement of navigation system performance accuracy, integrity, continuity, and availability necessary for operations within a defined airspace.

[12]

See and Avoid The ability of a pilot to see traffic which may be a conflict, evaluate flight paths, determine traffic right-of-way, and manoeuvre to avoid the traffic.

[12]

Segregated Airspace

Airspace that is segregated for exclusive use and into which other traffic is not permitted.

[5]

Sense and Avoid S&A Equivalent principle to See & Avoid (see definition), but applied to UAS and, thus substituting the ability of a pilot on board to ‘see’ any potentially conflicting traffic by the function ‘detect/sense’, which provides the UAS with the capability of recognising such traffic and identifying its characteristics (size, speed, direction)

Sense & Avoid System

S&A System A Sense & Avoid System comprises those components which enable a UAS to sense and avoid other airspace users in real-time; it may be on-board, or ground-based involving the pilot-in-command, or a combination of both.

[5]

Separation minima The minimum displacements between an aircraft and a hazard which maintain the risk of collision at an acceptable level of safety.

[9]

Separation mode An approved set of rules, procedures and conditions of application associated with separation minima.

[9]

Separation provision

The tactical process of keeping aircraft away from hazards by at least the appropriate separation minima.

[9]

Separator The agent responsible for separation provision for a conflict, being either the airspace user or a separation provision service provider. Note: The role of the separator may be delegated; however, a predetermined separator must be defined prior to the commencement of separation provision.

[9]







TERMINOLOGY ACRONYM DEFINITION REF.Single European Sky

SES The Single European Sky is a European Union initiative (launched in 1999, and legislation in 2004) which attempts to overcome the airspace fragmentation and capacity issues in Europe by structuring airspace and air navigation services at a pan-European level. The SES is considered the only way to provide a uniform and high level of safety over Europe’s skies. Other benefits include additional airspace capacity and greater efficiency of air navigation services.

([16])

Single European Sky ATM Research

SESAR SESAR (formerly known as SESAME) is the European R&D programme to implement the Single European Sky. It is coordinated and co-funded by the European Commission and EUROCONTROL, and comprises three phases: Definition Phase (2005-2008), Development Phase (2008-2013), and Deployment Phase (2014-2020)

Spacing Any application of a distance or time between an aircraft and a hazard at or above separation minima in order to maintain a safe and orderly flow of traffic.

[9]

Special Use Airspace

SUA Airspace of defined dimensions identified by an area on the surface of the earth wherein activities must be confined because of their nature and/or wherein limitations may be imposed upon aircraft operations that are not a part of those activities. Types of special use airspace are: Alert Area, Controlled Firing Area, Military Operations Area, Prohibited Area, Restricted Area, and Warning Area.

[12]

Special VFR Flight

A VFR flight cleared by air traffic control to operate within a control zone in meteorological conditions below VMC.

[8]

State aircraft Aircraft used in military, customs and police services.

[9]

Telecommand link The means used to transfer the pilot’s intent to the unmanned aircraft. The uplink portion of the control link between pilot and aircraft.

[12]







TERMINOLOGY ACRONYM DEFINITION REF.Telemetry Link The means used to transfer the unmanned

aircraft’s health and status to the pilot. It is the downlink portion of the control link between the pilot and aircraft.

[12]

Traffic a) A term used by a controller to transfer radar identification of an aircraft to another controller for the purpose of coordinating separation action. Traffic is normally issued:

1) In response to a handoff or point out, 2) In anticipation of a handoff or point out, or 3) In conjunction with a request for control of an aircraft.

b) A term used by ATC to refer to one or more aircraft.

[13]

All aircraft/vehicles that are within the operational vicinity of own-ship

[12]

UAS Commander A suitably qualified person responsible for the safe operation of a UAS during a particular flight and who has the authority to direct a flight under her/his command.

([11])

UAS Communication Link

The means to transfer command and control information between the elements of a UAS, or between the system and any external location. (e.g. Transfer of command and response data between control stations and aircrafts and between the UAS and Air Traffic Control).

([11])

UAS Control Station

UCS See Control Station

UAS Launch and Recovery Element

A facility or device(s) from which a UA is controlled during launch and/or recovery. There may be more than one launch and recovery element as part of a UAS.

([11])

UAS Operator The legal entity operating a UAS. ([11])

(UAS) Pilot-In-Command

(UAS) PIC The person in direct control of the UA. ([11])







TERMINOLOGY ACRONYM DEFINITION REF. Pilot in command means the person who:

1) Has final authority and responsibility for the operation and safety of the flight; 2) Has been designated as pilot in command before or during the flight; and 3) Holds the appropriate category, class, and type rating, if appropriate, for the conduct of the flight.

This concept is similar to the UAS commander (UAV commander) defined by the UAV Task Force (see UAS Commander)

[12]

Unmanned Aircraft UA An aircraft which is designed to operate with no human pilot onboard.

([11])

An aircraft or balloon that does not carry a human operator and is capable of flight under remote control or autonomous programming.

[14]

Unmanned Aircraft System

UAS

(Plural acronym is the same as the singular, UAS)

A UAS comprises individual elements consisting of the unmanned aircraft (UA), the “Control Station” (CS) and any other elements necessary to enable flight, such as a “Communication link” and “Launch and Recovery Element”. There may be multiple UA, CS, or Launch and Recovery Elements within a UAS. Note 1: This definition has been derived from that developed by ref. [11] for UAV System Note 2: This term (UAS) was firstly introduced by the US DoD, afterwards adopted by FAA and the EUROCAE WG-73, and finally by ICAO (2nd meeting of ICAO Informal Group on UAVs, on 11-12 January 2007) Note 3: “Flight” is defined as also including taxiing, takeoff and recovery/landing)

([11])

Unmanned Air/Aerial Vehicle

UAV Obsolete term (although still very commonly used). It must be substituted by Unmanned Aircraft – UA – (see definition)

Unmanned Air/Aerial Vehicle System

UAVS Obsolete term (although still very commonly used). It must be substituted by Unmanned Aircraft System – UAS – (see definition)

Visual Flight Rules VFR Rules that govern the procedures for conducting flight under visual conditions.

[12]







TERMINOLOGY ACRONYM DEFINITION REF.Visual Line of Sight VLOS Within a human’s unaided vision without the

use of any apparatus other than corrective lenses.

[12]

Visual Meteorological Conditions

VMC Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling, equal to or better than specified minima.

[8]

NOTATION: A reference between brackets means that the definition is based on that reference but it is not textual definition