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ReferenceDTR/SES-00332

KeywordsGNSS, location, navigation, performance, parameters,

satellite, system, terminal

TS 103 246-3 V0.2.3 (2014-12)

Satellite Earth Stations and Systems (SES); GNSS-based Location Systems;

Part 3: Performance Requirements

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TECHNICAL SPECIFICATIONTECHNICAL SPECIFICATION

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Individual copies of the present document can be downloaded from: http://www.etsi.org

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The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI

Secretariat.

Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at http://portal.etsi.org/tb/status/status.asp

If you find errors in the present document, please send your comment to one of the following services: http://portal.etsi.org/chaircor/ETSI_support.asp

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No part may be reproduced except as authorized by written permission.The copyright and the foregoing restriction extend to reproduction in all media.

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Contents

ETSI

TS 103 246-3 V0.2.3 (2014-12)7

Intellectual Property RightsIPR's essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPR’s, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: "Intellectual Property Rights (IPR’s); Essential, or potentially Essential, IPR’s notified to ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http://ipr.etsi.org).

Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPR’s not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document.

ForewordThis Technical Specification (TS) has been produced by ETSI Technical Committee Satellite Earth Stations and Systems (SES).

IntroductionThe increasing proliferation of location-based services is based on several trends in user applications and devices; these include notably the widespread adoption of multi-functional smart-phones etc., and the wider adoption of tracking devices (e.g. in transport). This need for new and innovative location-based services is generating a need for increasingly complex location systems. These systems are designed to deliver location-related information for one or more location targets to user applications.

The wide spectrum of technical features identified in [i.1] calls for a new and broader concept for location systems, taking into account hybrid solutions in which GNSS technologies are complemented with other technology sensors to improve robustness and the performance.

Hence a set of standards for GNSS-based Location Systems (GBLS) is defined as follows, of which the present document is part 3:

Part 1: ETSI TS 103 246-1: GNSS-based Location Systems; Part 1: Functional requirements Error: Reference source not found

Part 2: ETSI TS 103 246-2: GNSS-based Location Systems; Part 2: Reference Architecture [9]

Part 3: ETSI TS 103 246-3: GNSS-based Location Systems; Part3: Performance Requirements

Part 4: ETSI TS 103 246-4: GNSS-based Location Systems; Part4: Requirements for Location Data Exchange Protocols [i.2]

Part 5: ETSI TS 103 246-5: GNSS-based Location Systems; Part5: Performance Test Specification [i.3].

ETSI

TS 103 246-3 V0.2.3 (2014-12)8

1 ScopeThis document firstly defines the Performance Features for the data provided by the GNSS-based Location System (GBLS) to an external application module. This document then defines the performance requirements for these Performance Features.

The GBLS aims at providing location-related data for one or more targets operating in a range of environments.

2 ReferencesReferences are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the referenced document (including any amendments) applies.

Referenced documents which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference.

NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee their long term validity.

2.1 Normative referencesThe following referenced documents are necessary for the application of the present document.

[1] Galileo OS Signal in Space ICD, Issue 1.2,

[2] IS-GPS-200, Revision D, Navstar GPS Space Segment/Navigation User Interfaces,.

[3] IS-GPS-705, Navstar GPS Space Segment/User Segment L5 Interfaces,

[4] IS-GPS-800, Navstar GPS Space Segment/User Segment L1C Interfaces,.

[5] IS-QZSS, Quasi Zenith Satellite System Navigation Service Interface Specifications for QZSS.

[6] GLONASS Interface Control Document.

[7] BeiDou Navigation Satellite System Signal-In-Space Interface Control Document Open Service Signal (version 2.0)

[8] RTCA DO-229C. “Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment”..

[9] ETSI TS 103 246-1 “Satellite Earth Stations and Systems (SES); GNSS-based location systems; Part 1: Functional requirements”.

[10] ETSI TS 103 246-2 "Satellite Earth Stations and Systems (SES); GNSS-based location systems; Part 2: Reference Architecture”

2.2 Informative referencesThe following referenced documents are not necessary for the application of the present document but they assist the user with regard to a particular subject area.

[i.1] ETSI TR 103 183: "Satellite Earth Stations and Systems (SES); Global Navigation Satellite Systems (GNSS) based applications and standardisation needs".

[i.2] ETSI TS 103 246-4: "Satellite Earth Stations and Systems (SES); GNSS-based location systems; Part 4: Requirements for Location Data Exchange Protocols”

[i.3] ETSI TS 103 246-5: "Satellite Earth Stations and Systems (SES); GNSS-based location systems; Performance Test Specification.”

ETSI

TS 103 246-3 V0.2.3 (2014-12)9

http://docbox.etsi.org/Reference

[i.4] IEEE 802.11 for WiFi

[i.5] IEEE 802.15 for Wireless Personal Area Network (short range wireless)

[i.6] IEEE 802.15.1 for Bluetooth

[i.7] IEEE 802.15.4a for low rate WPAN

[i.8] 3GPP TSXX;XXX for 2G



[i.11] [FFS] for 5G

ETSI

TS 103 246-3 V0.2.3 (2014-12)10

3 Definitions, symbols and abbreviations3.1 DefinitionsThe following terms and definitions apply:

RJM: all to be reviewed below

Architecture: abstract representation of a communications system, in this case representing functional elements of the system and associated logical interfaces.

Assistance: Use of position data available from a telecommunications network to enable a GNSS receiver to acquire and calculate position (A-GNSS) under adverse satellite reception conditions:

Availability: percentage of time when a location system is able to provide the required location-related data. Note that the required location-related data might vary between location based applications. It may not only contain a required type of information (e.g. position and speed), but also a required quality of service (e.g. accuracy, protection level, authenticity).

Class A, B, C: Classes are defined in order to categorise the performance level of the GBLS for a given performance feature. The classes are based on different implementations of the reference architecture [9], and these implementations can be classed differently for each Feature. In all cases Class A is the highest performance class and C is the lowest.

Continuity: Likelihood that the navigation signal-in-space supports accuracy and integrity requirements for duration of intended operation. It guarantees that a user can start an operation during a given exposure period without an interruption of this operation and assuming that the service was available at beginning of the operation. Related to the Continuity concept, a Loss of Continuity occurs when the user is forced to abort an operation during a specified time interval after it has begun (the system predicts service was available at start of operation).

Continuity Risk is the probability of detected but unscheduled navigation interruption after initiation of an operation.

Electromagnetic Interference: Any source of RF transmission that is within the frequency band used by a communication link, and that degrades the performance of this link. Jamming is a particular case of electromagnetic interference, where an interfering radio signal is deliberately broadcast to disrupt communication.

Integrity: a measure of the trust in the accuracy of the location-related data provided by the location system. It is expressed through the computation of a protection level. The Integrity function includes the ability of the location system to provide timely and valid warnings to users when the system must not be used for the intended operation. Specifically, a location system is required to deliver a warning (an alert) of any malfunction (as a result of a set alert limit being exceeded) to users within a given period of time (time-to-alert). Related to the Integrity concept, a Loss of Integrity event occurs when an unsafe condition occurs without annunciation for a time longer than the time-to-alert limit.

Integrity risk: the probability (per operation or per unit of time) that the system generates an unacceptable error without also providing a timely warning that the system’s outputs cannot be trusted.

Jamming: The deliberate transmission of interference to disrupt processing of wanted signals, which in this case are GNSS or telecommunication signals. N.B. Spoofing is considered to be a deceptive form of jamming.

Latency: the time elapsed between the event triggering the determination of the location-related data for (a) location target(s) (i.e. location request from external client, external or internal event triggering location reporting), and the availability of the location-related data at the user interface.

Location-based application: An application that is able to deliver a location-based service to one or several users.

Location-based service: A service built on the processing of the Location-related data associated with one or several location targets

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TS 103 246-3 V0.2.3 (2014-12)11

Location-related data: A set of data associated with a given location target, containing at least one or several of the following time-tagged information elements: target position, target motion indicators (velocity and acceleration), and Quality of Service indicators (estimates of the position accuracy, reliability or authenticity).

NOTE: This data is the main output of a Location system.

Location system: The system responsible for providing to a location based application the Location-related data of one or several location targets.

Location target: The physical entity on whose position the location system builds the location-related data. This entity may be mobile or stationary.

Privacy: a function of a location system that aims at ensuring that the location target user private information (identity, bank accounts etc.) and its location-related data cannot be accessed by a non authorised third party.

Protection level: the radius of a circle with its centre at the true location target position, which describes the limit of the error of the position data in the plane. In other words, the upper bound to the position error such that: P(> PL) < Irisk, where Irisk is the Integrity risk and is the actual position error. The protection level is provided by the location system, and with the integrity risk, is one of the two sub-features of the integrity system. The protection level is computed both in the vertical and in the horizontal position domain and it is based on conservative assumptions that can be made on the properties of the GNSS sensor measurements, i.e. the measurement error can be bounded by a statistical model and the probability of multiple simultaneous measurement errors can be neglected.

Pseudo-Random Noise Code (PRN): unique binary code (or sequence) transmitted by a GNSS satellite to allow a receiver to determine the travel time of the radio signal from satellite to receiver

Quality of service: a set of indicators that can accompany the location target’s position/motion information and is intended to reflect the quality of the information provided by the location system. QoS indicators can be an accuracy estimate, a protection level statistic, integrity risk, authenticity flag.

Security: a function of a location system that aims at ensuring that the location-related data is safeguarded against unapproved disclosure or usage inside or outside the location system, and that it is also provided in a secure and reliable manner that ensures it is neither lost nor corrupted.

Spoofing: the transmission of signals intended to deceive location processing into reporting false target data (otherwise known as structural interference) e.g. meaconing.

Time-to-alert: the time from when an unsafe integrity condition occurs to when an alerting message reaches the user

Time-to-first-fix: refers to the time needed by the receiver to perform the first position fix whose accuracy is lower than a defined accuracy limit, starting from the moment it is switched on.Vertical axis: axis locally defined for the location target, collinear to the zenith/nadir axis.

3.2 SymbolsFor the purposes of the present document, the following symbols apply:

Carrier phaseεAccel Error on sensor acceleration (from INS)εAtt Error on sensor attitude (from INS)εGyro Error on sensor gyroscopes (from INS)εPos Error on sensor position (from INS)εPos3D Uncertainty on sensor position (from GNSS)εV Error on sensor attitude (from INS)εV3D Uncertainty on sensor speed (from GNSS)d Carrier DopplerPGNSS Position estimate coming from GNSS sensorPINS Position estimate coming from the INSVGNSS Speed estimate coming from GNSS sensorVINS Speed estimate coming from the INSPFA

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TS 103 246-3 V0.2.3 (2014-12)12

3.3 AbbreviationsFor the purposes of the present document, the following abbreviations apply:

All below to be reviewed

3GPP 3rd Generation Partnership ProjectADAS Advanced Driver Assistance SystemsA-GNSS Assisted GNSSAL Alarm LimitBTS Base station Transceiver SystemD-GNSS Dynamic GNSS DoA Direction of ArrivalECEF Earth Centred, Earth FixedEDGE Enhanced Data for GSM EvolutionEGNOS European Geostationary Navigation Overlay SystemEMI Electro-Magnetic InterferenceFDAF Frequency Domain Adaptive FilteringFFS For Further StudyGBLS GNSS-based Location SystemGCF Global Certification ForumGEO Geostationary Earth OrbitGIVE Grid Ionospheric Vertical ErrorGLONASS Global Navigation Satellite System (Russian based system)GNSS Global Navigation Satellite SystemGPRS General Packet Radio ServiceGPS Global Positioning SystemGSM Global System for Mobile communicationsHDOP Horizontal Dilution of PrecisionHPE Horizontal Positioning ErrorHPL Horizontal Protection LevelIMU Inertial Measurement UnitINS Inertial Navigation Sensor IRS Inertial Reference SystemITS Intelligent Transport SystemsLCS LoCation ServicesLEO Low Earth OrbitLOS Line Of SightLTE Long-Term EvolutionMEMS Micro Electro-Mechanical SystemsMEXSAT Mexican Satellite SystemMI Mis-IntegrityMMI Man-Machine InterfaceMOPS Minimum Operational Performance SpecificationMP MultipathMPS Minimum Performance StandardMS Mobile StationNCO Numerically Controlled OscillatorNMR Network Measurement ResultsODTS Orbit Determination and Time SynchronisationOMA Open Mobile AllianceOTDOA Observed Time Difference of ArrivalPAYD Pay As You DrivePE Positioning ErrorPL Protection LevelPPD Personal Privacy DevicePRN Pseudo-Random Noise codePRS Public Regulated ServicesPVT Position, Velocity and TimePPP Precise Point PositioningQoS Quality of Service

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TS 103 246-3 V0.2.3 (2014-12)13

QZSS Quasi-Zenith Satellite SystemRAIM Receiver Autonomous Integrity MonitoringRF Radio FrequencyRMS Root Mean SquareRTCA Radio Technical Commission for AeronauticsRTK Real Time KinematicRx ReceiverSBAS Satellite Based Augmentation SystemSCN Satellite Communications and Navigation (Working Group of TC-SES)SMLC Serving Mobile Location CentreSUPL Secure User Plane for LocationSV Satellite VehicleTBC To Be ConfirmedTBD To Be DefinedTC-SES Technical Committee Satellite Earth Stations and SystemsTSP Total Spoofing PowerTTA Time to AlarmTTFF Time-to-first-fixUDRE User Differential Range ErrorUERE User Equivalent Range ErrorUHF Ultra-High FrequencyUMTS Universal Mobile Telecommunications SystemVPL Vertical Protection LevelWAAS Wide Area Augmentation SystemWI-FI Wireless Fidelity

ETSI

TS 103 246-3 V0.2.3 (2014-12)14

4 Location System Performance Features4.1 GeneralThe location-related data delivered by GNSS-based Location Systems is required to meet a number of requirements, particularly in terms of positioning performance. In this document, these requirements are referred to as “Performance Features”.

These features are derived from the system performance requirements defined in [9].

These performance features encompass several attributes and are described in the sub-clauses below. Clause 5 then defines the requirements for each feature in terms of an associated set of performance metrics (i.e. measurement parameters) defines the performance values for these metrics and the conditions in which they apply.

The specific performance metrics for these features are defined in Annex A.

The applicable conditions for the performance requirements are defined in Annex B.

Specific scenarios applicable to some performance features are defined in. Annex C.

The relationship of the Performance Features to the Annexes is as follows:

Performance Feature Performance Metrics Applicable Conditions Specific ScenariosHorizontal Position Accuracy: A.1 B.1, B.2Vertical Position Accuracy A.2 B.1, B.2GNSS Time Accuracy A.3 B.1, B.2Time-to-first-fix A.4 B.1, B.2Position Authenticity A.5 B.1 C.1Robustness to Interference A.6, A.7 B.2GNSS Sensitivity A.8 B.2Position Integrity (Protection Level) A.9 B.2 C.2

NOTE: additional features are for further study (FFS); other features identified but considered out of scope at present are:

Availability of Required Accuracy

EMI Localisation Accuracy

GNSS-Denied Accuracy

Position Integrity (Time-to-Alert)

Position Integrity (Time-to-Recover-from-Alert)

Accuracy of speed and acceleration (horizontal and vertical).

4.1.1.1 Performance Features

4.1.2 Horizontal Position AccuracyThis Feature is the maximum error of the horizontal position of a Location target reported by the Location System.

The requirements for this feature can range from relaxed constraints for personal navigation applications, to more stringent ones for liability-critical applications, such as road charging, dangerous cargo tracking.

4.1.3 Vertical Position AccuracyThis Feature is the maximum error of the vertical position of a location target reported by the Location System.

This feature applies when vertical guidance is required, for instance to allow position coordinates provided to an emergency indoor caller to result in an “actionable location” for emergency response, especially in urban environments.

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TS 103 246-3 V0.2.3 (2014-12)15

4.1.4 GNSS Time Accuracy The GNSS time accuracy is the difference between the true GNSS time (as implemented in the GNSS system timing facility) and the time restituted by the GNSS processor based on the PVT solution.

Applications requiring synchronisation of assets distributed across wide geographical areas can use GNSS time as a reference, for example.

4.1.5 Time-to-First-Fix (TTFF)The TTFF is the time taken by the Location System to provide target (non-interferer??) position data starting either from the reception of a request, or from another triggering event (for instance for periodic or geo-dependant reporting).

The TTFF is defined for a cold-start condition for the GBLS. Depending on GBLS capability, at GNSS sensor level the following start conditions are used for the definition of performance requirements:

1. cold-start (no assistance).

2. assisted cold-start with coarse time assistance.

3. assisted cold-start with fine time assistance

The defined classes of performance (A, B, C) correspond to these conditions, but in a non-.specific mapping.

The detailed conditions are shown in the table below:

Starting condition

Time at GNSS sensor start

Position at GNSS sensor start

GNSS Satellites

Ephemerides

Precise Time of Week

Cold Start (Autonomous)

Not known Not known Decoded from satellite data

Decoded from satellite data

Assisted Cold Start (either coarse or fine time)

Retrieved from assistance data:Coarse-time: 2 s,Fine time: 10 s

Retrieved from assistance data: 3 km (horizontal error); up to 500 m (altitude)

Retrieved from assistance data

Coarse Time: Decoded from satellite data, or calculated as additional state of the navigation.Fine Time: From assistance data

Note: Cold-start only is considered because it offers discrimination between system configurations.

Note: Cold-Start is defined as: the receiver is absent, or has inaccurate estimates of, its position, velocity, the time, or the visibility of any of the GNSS satellites. As such, the receiver must systematically search for all possible satellites. After acquiring a satellite signal, the receiver can begin to obtain approximate information on all the other satellites, called the almanac.

4.1.6 Position AuthenticityRF spoofing may affect the analysis of location target signals resulting in false position data.

Position Authenticity gives a level of assurance that the data for a location target has been derived from real signals relating to the target.

4.1.7 Robustness to InterferenceLocation Systems might be required to operate in constrained RF environments, in particular in the GNSS frequency bands. The performance feature “robustness to interference” is the ability of the receiver to operate under interference conditions, and maintain an appropriate level of performance.

The performance metrics used to characterise this performance feature are:

the “PVT degradation under interference conditions” defined in Annex A.

the " recovery time of normal performance”, defined in Annex A.

ETSI

TS 103 246-3 V0.2.3 (2014-12)16

Robert Mort, 05/12/36,

http://en.wikipedia.org/wiki/GPS_signals#Almanac

The type of metric used to characterise the Location System performance depends on the way the system implements the feature.

4.1.8 GNSS SensitivityGNSS Sensitivity refers to the minimum RF signal power at the receiver input required for a specified reliability of location-related data provision when either:

GNSS signals are first acquired, or

GNSS tracking is in operation (e.g. the positioning module antenna suffers an attenuated propagation channel).

The latter is typically applicable for Location Systems operating in urban or indoor environments, when GNSS signals can be significantly attenuated.

4.1.9 Position Integrity (Protection Level)Position Integrity is the ability of the Location System to measure the trust that can be placed in the accuracy of the location target position.

It is relevant to Safety- and Liability-Critical applications (e.g. critical navigation, billing) where integrity is important.

It is expressed through the computation of a protection level associated to a predetermined integrity risk (as a function of the type end-user application) see [7].

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TS 103 246-3 V0.2.3 (2014-12)17

5 Performance RequirementsThis clause defines the performance requirements for each of the performance features defined in clause 4.

The Performance Features are defined in each case for a range of operating conditions, where applicable, including:

1. Location Target motion types:

moving

static

2. location target environments:

Open area

Urban,

Asymmetric area (explanation…………..)

3. GNSS-based location system types (Class A, B, C)

4. clear signal (non-interfered) or signal interference conditions etc.

These ranges of environments and receiver types have been chosen as the most representative of those commonly encountered today.

Note: Classes are defined in order to categorise the performance level of the GBLS for a given performance feature. The classes are based on different implementations of the reference architecture [9], and these implementations can be classed differently for each Feature. In all cases Class A is the highest performance class and C is the lowest.

5.1 Horizontal Position AccuracyThe Horizontal Position data provided by the location system shall comply with the performance requirements defined for moving and static location target cases in the sub-clauses below.

Location Target Environments are all those defined in Annex B.2.

5.1.1 Use case: Moving Location Target

5.1.1.1 Motion

The location target follows the trajectory described in Annex B.3. The reference point {0;0;0} has coordinates expressed in [WGS84] system: longitude = 7°03'12" East, latitude = 43°37'00" North.

The trajectory parameters are:

Table 5-1: Location target trajectory parameters

Trajectory parameter

Value for outdoor trajectory

Value for indoor trajectory

v1 25 km/h 1 km/hv2 100 km/h 4 km/hv3 100 km/h 4 km/hd1 250 m 10 mD2 250 m 10 m

NOTE: the above values correspond with those of 3GPP [ref ]

ETSI

TS 103 246-3 V0.2.3 (2014-12)18

Jérémie Giraud, 05/12/36,

Proposed reference point.It is ETSI location in Sophia Antipolis

5.1.1.2 Performance requirement

This performance shall be met when the trajectory is followed in both directions.

Table 5-2: Horizontal Position Accuracy, Moving target, Open Area

Metric Max position error (m)Class A Class B Class C

Mean error 0,2 0,5 8,4Standard deviation 0.2 0.6 5.2

50th percentile 0.2 0.6 6.767th percentile 0,3 0,7 8,895th percentile 0,4 0,8 22,199th percentile 0,5 1,4 23,8

Mean cross track error 0,1 0,2 4,8Cross track error - 67th percentile 0,1 0,3 5,8Cross track error - 95th percentile 0,2 0,7 16,5Cross track error - 99th percentile 0,3 1,2 20

Mean along track error 0,2 0,3 5,4Along track error - 67th percentile 0,3 0,3 6,4Along track error - 95th percentile 0,4 0,5 21,9Along track error - 99th percentile 0,5 1 22,4

Table 5-3: Horizontal position Accuracy, Moving target, Urban Area,

Metric Max position error (m) – Urban AreaClass A Class B Class C

Mean value 1,6 24,2 40,8Standard deviation 1.7 17.2 17.2

50th percentile 0,5 20,9 42,167th percentile 0,8 29,2 52,595th percentile 9,3 49,9 75,399th percentile 19 62,9 98,7

Cross track error - Mean value 1 15,2 26,9Cross track error - 67th percentile 0,6 18,8 37,9Cross track error - 95th percentile 3,7 42,6 59Cross track error - 99th percentile 13,8 51,4 66,9

Along track error - Mean value 1,1 15,4 21,9Along track error - 67th percentile 0,5 19,2 25,6Along track error - 95th percentile 6,2 44,3 68,3Along track error - 99th percentile 14,6 56,3 90,4

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TS 103 246-3 V0.2.3 (2014-12)19

Table 5-4: Horizontal position Accuracy, Moving target, Asymmetric Area,

Metric Max position error (m) – Asymmetric AreaClass A Class B Class C

Mean value 0,5 12,1 31,7Standard deviation 0.5 5 19.8

50th percentile 0,4 9,1 36,567th percentile 0,5 13,6 45,495th percentile 1 38 7999th percentile 1,2 54,9 99,5

Cross track error - Mean value 0,3 10,2 15,3Cross track error - 67th percentile 0,4 11,4 19,3Cross track error - 95th percentile 0,8 32,4 59Cross track error - 99th percentile 1,1 50,4 77,3

Along track error - Mean value 0,3 5,1 21,4Along track error - 67th percentile 0,3 5,6 33,6Along track error - 95th percentile 0,6 18,3 68,1Along track error - 99th percentile 0,9 28,3 92

5.1.2 Use case: Static Location Target

5.1.2.1 Target position

The location target is located in coordinates expressed in WGS84 system: : longitude = 7°03'12" East, latitude = 43°37'00" North.


Table 5-5: Horizontal Position Accuracy, Static target, Open area,

Metric Max position error (m) – open areaClass A Class B Class C

Mean value 0,3 1,2 2,4Standard deviation 0,2 0,5 1,1

50th percentile 0,2 0,5 0,767th percentile 0,4 0,7 1,395th percentile 0,5 1,1 3,899th percentile 0,5 2,2 8,5

Table 5-6: Horizontal Position Accuracy, Static target, Urban Area,

Metric Max position error (m) – urban areaClass A Class B Class C



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TS 103 246-3 V0.2.3 (2014-12)20



Table 5-7: Horizontal Position Accuracy, Static target, Asymmetric Area,

Metric Max position error (m) – asymmetric areaClass A Class B Class C



5.2 Vertical Position AccuracyThe Vertical Position data provided by the location system shall comply with the requirements defined for moving and static location target cases in the sub-clauses below.



5.2.1.1 Motion

The location target follows the trajectory described in clause B.3. The reference point {0;0;0} has coordinates expressed in [WGS84] system: longitude = 7°03'12" East, latitude = 43°37'00" North.

The trajectory parameters are provided in the table below.

Table 5-8: Location target movement parameters






This performance shall be met when the trajectory is travelled in both directions.

Table 5-9 vertical Position Accuracy, moving location target, open area




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TS 103 246-3 V0.2.3 (2014-12)21



Table 5-10 vertical Position Accuracy, moving location target, urban area,



50th percentile 1 6,,5 18,767th percentile 1,6 8,9 26,295th percentile 2,9 13,2 35,299th percentile 3,9 17,5 81,4

Table 5-11 vertical Position Accuracy, moving location target, asymmetric area






The location target is located in coordinates expressed in WGS84 system: : longitude = 7°03'12" East, latitude = 43°37'00" North..


Table 5-12 Vertical position accuracy, Static location target, Open Area

Metric Max position error (m) – Open AreaClass A Class B Class C


50th ercentile 0,3 2,1 5,667th percentile 0,5 2,9 6,995th percentile 0,8 4,6 8,499th percentile 1,5 6,5 10,2

Table 5-13 vertical Position Accuracy, static location target, urban area

Metric Max position error (m) – urban areaClass A Class B Class C

Mean value 3,1 6,3 20,1Standard deviation 3,2 5,2 21


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Table 5-14 Vertical Position Accuracy, static location target, asymmetric area

Metric Max position error (m) – asymmetric areaClass A Class B Class C


50th percentile 8,1 16,1 41,767th percentile 10,1 22,4 55,495th percentile 13,2 31 69,199th percentile 15,7 34,5 80,1

5.3 GNSS Time AccuracyThe GNSS Time provided by the location system shall comply with the performance requirements defined for moving and static location target cases in the sub-clauses below.



5.3.1.1 Motion

The location target follows the trajectory described in clause B.3. The reference point {0;0;0} has coordinates expressed in [WGS84] system: : longitude = 7°03'12" East, latitude = 43°37'00" North..


Table 5-15: Location target movement parameter






This performance shall be met when the trajectory is travelled both ways.

Table 5-16 GNSS time Accuracy: moving Location target, open area

Metric Maximum time error (m)Class A Class B Class C

Mean value 0,2 1.1 2.895th percentile 0.4 2.9 4.9

Table 5-17 GNSS time Accuracy: moving Location target, urban area

Metric Maximum time error (m)Class A Class B Class C

Mean value 2.3 6.5 18.895th percentile 3.9 14.5 35.4

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TS 103 246-3 V0.2.3 (2014-12)23



Table 5-18 GNSS time Accuracy: moving Location target, asymmetric area

Metric Maximum time error (s)Class A Class B Class C




The location target is located in coordinates expressed in WGS84 [TBC] system: longitude = [TBD], latitude = [TBD].


Table 5-19 GNSS time Accuracy: static location target, open area



Table 5-20 GNSS time Accuracy: static location target, urban area



Table 5-21 GNSS time Accuracy: static location target, asymmetric area



5.4 Time-to-First-Fix (TTFF)Applicable GNSS signals are defined in Annex B.1.


5.4.1 Use case: Moving Target

5.4.1.1 Motion

The location target follows the trajectory described in Annex B. The reference point {0;0;0} has coordinates expressed in [WGS84] system: longitude = 52 deg. 12 min., latitude = 4 deg. 25 min., altitude 0 m .


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TS 103 246-3 V0.2.3 (2014-12)24



Value

v1 25 km/hv2 100 km/hv3 100 km/hd1 250 mD2 250 m


This performance shall be met when the trajectory is traversed in both directions.

Table 5-23 TTFF: moving location target, open area

Metric Performance requirement – Open AreaClass A Class B Class C

TTFF[s]Mean value 1.55 2.5 29.8

Standard deviation 0.12 0.4 4.967th percentile 1.56 2.7 30.295th percentile 1.62 3.3 36.999th percentile 2.21 3.8 38.8

Minimum Value 1.36 1.8 19.3Maximum Value 2.27 3.8 39.0

The above values are dependent on achieving a maximum positioning error of 100 m

Horizontal Position Error [m]Mean value 6.40 5.6 7.0


Table 5-24 TTFF: moving location target, Urban area,

Metric Performance requirement – urban AreaClass A Class B Class C







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TS 103 246-3 V0.2.3 (2014-12)25

Table 5-25 TTFF: moving location target, asymmetric area

Metric Performance requirement – asymmetric areaClass A Class B Class C

TTFF [s]Mean value 1.50 5.4 n/a (Note1 )

Standard deviation 0.54 2.1 n/a (Note1 )67th percentile 1.43 5.3 n/a (Note1 )95th percentile 1.95 9.7 n/a (Note1 )99th percentile 4.78 15.1 n/a (Note1 )

Minimum Value 1.21 2.7 n/a (Note1 )Maximum Value 6.40 16.6 n/a (Note1 )


Horizontal Position Error [m]Mean value 15.02 17.4 n/a (Note1 )

Standard deviation 9.73 21.7 n/a (Note1 ) 67th percentile 16.86 14.3 n/a (Note1 )95th percentile 34.91 54.4 n/a (Note1 ) 99th percentile 46.21 99.2 n/a (Note1 )

Note1. Class C receivers cannot achieve a position fix in the asymmetric area scenario

Table 5-26 TTFF: moving location target, with interference (Medium level: -9 dB), Urban area

Metric Performance requirement – urban AreaClass A Class B Class C







Table 5-27 TTFF: moving location target with interference (Medium level: - 9 dB), asymmetric area


TTFF [s]Mean value 10.49 21.0 n/a (Note1 )






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TS 103 246-3 V0.2.3 (2014-12)26

5.4.2 Use case: Static Target


The location target is located in coordinates expressed in WGS84 system: longitude = 4° 25′ 00″ E, latitude = 52° 12′ 00″ N.


Table 5-28 TTFF: static location target, open area

Metric Performance requirement – Open AreaClass A Class B Class C







Table 5-29 TTFF: static location target, Urban area

Metric(as per clause 4.2)

Performance requirement – urban AreaClass A Class B Class C





Max Horizontal Position Error [m]Mean value 17.06 29.4 30.0


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TS 103 246-3 V0.2.3 (2014-12)27

Table 5-30 TTFF: static location target, asymmetric area


TTFF[s]Mean value 1.98 5.4 n/a (Note1 )






5.5 Position AuthenticityGBLS’s authenticate the estimated positions by means of specific algorithms that detect, and possibly mitigate, the presence of structured RF interference (i.e. RF spoofing, see [9]). The performance of the location system can be evaluated in terms of:

Probability of detection (PD ): the probability that the location system detects false GNSS signals during an RF spoofing attack;

Probability of false alarm (PFA ): the probability that the location system detects false GNSS signals with no RF spoofing attack.

Two main use cases are considered: 1) moving location target and 2) static location target. For each of these two use cases, the requirements cover:

- Clear scenario, where no structured interfering signals are considered. Location system performance is

measured by PFA ;

- Interference scenario, where elementary structured interfering signals are considered. Location system

performance is measured by PD .

5.5.1 Operational conditionsApplicable GNSS signals are defined as per clause B.1.

The operational environments, applicable for the location system performance requirements is the Open Area (see the related parameters in Annex B.2), either in clear or interference scenarios.

5.5.2 Use case: Moving location targetThe location target follows the trajectory described in Annex C. The reference point {0;0;0} has coordinates expressed in [WGS84] system: longitude = 7.0528 deg, latitude = 43.6169 deg.

The location target moves on a straight trajectory at a uniform speed, equal to 50 km/h.

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TS 103 246-3 V0.2.3 (2014-12)28

5.5.2.1 Clear Scenario

The PFA achieved by the location system “position authenticity” function shall meet the level specified in the table below, depending on the class of the location system. This performance shall be met when the trajectory is traversed both ways.

Table 5-31: PFA requirement

Environment type

Maximum False Alarm probabilityClass A Class B Class C

Open area 210-3 10-2 0.1In addition to the requirements above, the latency to provide authenticity shall not exceed 5 seconds.

5.5.2.2 Interference (Spoofing) Scenario

The location system shall meet the following performance requirements in terms of PD .

For a given interference scenario (see Table 5-60), the table below indicates:

the associated value of TSP;

the value of the error induced by the RF spoofing attack that the location system shall be able to detect. The type of error depends on the model corresponding to the interference scenario;

the PD as a function of the Class of the location system.

Table 5-32: PD performance, open area, moving location target

Interference scenario

TSP[dBW]

Minimum Error Minimum PD

Class A Class B Class CM-1 -143.5 0.5510-6 s 0.85 0.75 0.68

-142.5 0.6610-6 s 0.92 0.85 0.8-141.5 0.7510-6 s 0.98 0.95 0.9

M-2 -147.5 170 m 0.85 0.75 0.68-146.5 200 m 0.92 0.85 0.8-145.5 228 m 0.98 0.95 0.9

M-3 -147.5 57 m 0.85 0.75 0.68-146.5 70 m 0.92 0.85 0.8-145.5 78 m 0.98 0.95 0.9

Note 1: Scenarios M-4 and M-5 are FFS.

Note: In addition to the requirements above, the latency to provide authenticity shall not exceed 5 seconds.

5.5.3 Use case: Static Location Target The location target is static with reference coordinates expressed in WGS84 system: longitude = 7.0528 deg, latitude = 43.6169 deg..

5.5.3.1 Clear scenario

The false alarm probability achieved by the location system “position authenticity” function shall meet the level specified in the table below, depending on the class of the system.

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TS 103 246-3 V0.2.3 (2014-12)29

Table 5-33:

Environment type Maximum False Alarm probabilityClass A Class B Class C

Open area 510-4 210-3 10-2

Note: In addition to the requirements above, the latency to provide authenticity shall not exceed 5 seconds.

5.5.3.2 Interference (Spoofing) scenarios

For a given interference scenario, the indicated TSP and error values are the TSP and error (jump or drift depending of the applicable model in the scenario) values that the system is able to detect. This required ability is given as a function of:

the Class of the location system

the operational environment considered, as defined in clause B.2.3.

Table 5-34: PD performance, open area, static location target

Interference scenario

Minimum TSP

Minimum Error Minimum PD

Class A Class B Class CS-3 -156.09 0.4810-6 s 0.90 0.75 0.63

-154.46 0.5810-6 s 0.95 0.90 0.85-153.5 0.6810-6 s 0.98 0.97 0.95

S-4 -156.09 145 m 0.90 0.75 0.63-154.46 175 m 0.95 0.90 0.85-153.5 205 m 0.98 0.97 0.95

S-5 -156.09 40 m 0.90 0.75 0.63-154.46 48 m 0.95 0.90 0.85-153.5 56 m 0.98 0.97 0.95

Note 1: Scenarios S-1 and S-2 are FFS.

Note 2: In addition to the requirements above, the latency to provide authenticity shall not exceed 5 seconds.

5.6 Robustness to InterferenceThe performance parameters which characterise the robustness to interference are the following:

- Position fix availability as a function either of the jammer distance or the jamming-to-GNSS signal power ratio (J/S)

- Position fix accuracy (3D) with degradation under interference conditions

The robustness to interference is characterised by the maximum tolerable J/S, which is defined as that providing a position fix availability greater than 90% with a maximum horizontal error of 100 m. The horizontal position error statistics provided are based on position fixes satisfying the condition of a maximum horizontal error of 100 m.

5.6.1 Operational conditionsThe table below defines the operational conditions for “Robustness to Interference” and the masking parameters applicable for each of them.

Table 5-35: Environment applicability for “Robustness to Interference”

Environment type Applicability Masking parameters Interference

Open area Yes Nominal J#1, J#2Urban No -

Asymmetric area No -

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TS 103 246-3 V0.2.3 (2014-12)30


Horizontal error only?

the interference sources as defined in 5.7.2.2.1B.2.3.2 where two jamming sources (J#1 and J#2) are specified with 10 and 20 MHz FM deviation.

5.6.2 Case 1: 20 MHz FM deviationTable 5-36: performance parameters for “Robustness to Interference” with J#1

Metric Performance requirement Class A Class B Class C

maximum J/S (dB) 89.0 83.0 77.0minimum Jammer distance (m) 64.5 28.0 45.1

3D Position Error [m]Mean value 64.0 64.0 64.0


Table 5-37: Position fix accuracy (3D) with degradation under interference conditions with J#1

J/S [dB] Horizontal Position Error [m] Class

AClass

BClass

CMean value

67th percentile 95th percentile 99th percentile Standard deviation

< 85 < 78 < 72 46.7 47.6 50.1 51.4 1.9

85 79 73 52.6 54.6 59.1 60.0 3.6

86 80 74 52.5 52.1 63.5 66.8 4.5

87 81 75 55.2 55.9 61.9 66.5 3.1

88 82 76 52.7 54.4 74.2 76.5 8.4

89 83 77 64.1 61.8 96.2 99.7 15.7

5.6.3 Case 2: 10 MHz FM deviationTable 5-38: performance parameters for “Robustness to Interference” with J#2

Metric Performance requirement – suburban AreaClass A Class B Class C

maximum J/S (dB) 70 64 58minimum Jammer distance (m) 68 87 105



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TS 103 246-3 V0.2.3 (2014-12)31

Table 5-39: Position fix accuracy (3D) with degradation under interference conditions with J#2

J/S [dB] Horizontal Position Error [m] Class

AClass

BClass

CMean value

67th percentile 95th percentile 99th percentile Standard deviation

< 67 < 61 < 55 44.2 44.3 46.5 46.7 1.1

67 61 55 48.6 45.1 65.3 69.6 6.4

68 62 56 49.2 49.0 65.9 78.6 6.4

69 63 57 50.1 50.3 79.7 93.8 11.3

70 64 58 52.6 49.9 87.6 94.2 12.8

5.7 GNSS SensitivityGNSS Sensitivity is defined in terms of the maximum masking values tolerated by the location system allowing the provision of the required location-related data. It is specified for tracking and acquisition respectively.

The Tracking Sensitivity is defined as the maximum attenuation which allows the receiver to provide a position fix with an horizontal position error below 100 m and a probability greater than 90%.

The Acquisition Sensitivity is defined as the maximum attenuation which allows the receiver to have a first position fix within 300s with an horizontal position error below 100 m and a probability greater than 90%.

5.7.1 Operational conditionsThe table below defines the operational conditions for “GNSS sensitivity” and the masking parameters applicable for each of them.

Table 5-40: Environment applicability for “GNSS sensitivity”

Environment type Applicability Masking parameters

Open area Yes Special: see belowUrban No -

Asymmetric area Yes Special: see below

5.7.1.1 Special masking conditions

For low received GNSS signal power, use cases are defined in operational environments:

- “open Area” : fixed x2 > 100 dB and variable x1 > 0 dB

- and “asymmetric area”: fixed x1 = 0dB, fixed x2 > 100 dB and variable x3 > 0 dB

The maximum masking values tolerated by the location system will be determined, i.e. allowing the provision of the required location-related data.

5.7.1.2 Initial GNSS time estimate

Two different receiver starting conditions are made applicable to the two different masking conditions:

- “open Area” : Assisted Cold start with fine time estimate

- and “asymmetric area” : Assisted Cold start with coarse time estimate.

5.7.2 Use case: Moving Target

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Paolo Crosta, 28/11/14,

REWRITE in terms of attenuation

5.7.2.1 Target movement

The location target follows the trajectory described in clause B.3. The reference point {0;0;0} has coordinates expressed in [WGS84] system: longitude = 52 deg. 12 min., latitude = 4 deg. 25 min., altitude 0 m.

The trajectory parameters are provided in the table below with different values depending on the type of user.



Outdoor (vehicle)

Indoor (pedestrian)



This performance shall be met when the trajectory is travelled in reverse directions.

Table 5-42: GNSS acquisition sensitivity, Open area (fine time assistance)

Metric maximum signal power attenuation (dB)Class A Class B Class C

x1 32 20 16x2 >100 >100 >100

Table 5-43: GNSS tracking sensitivity, Open area (fine time assistance)


x1 33 28 28x2 >100 >100 >100

Table 5-44: GNSS acquisition sensitivity, asymmetric area (coarse time assistance)


x1 0 0 0x2 >100 >100 >100x3 n/a 26 dB n/a

Table 5-45: GNSS tracking sensitivity, asymmetric area (coarse time assistance)


x1 0 0 0x2 >100 >100 >100x3 n/a 28 n/a

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TS 103 246-3 V0.2.3 (2014-12)33

Annex A (normative): Definition of Performance MetricsThis Annex defines how performance shall be determined for each Performance Feature. Each Metric defined in the sub-clauses below corresponds to a Feature defined in clause 4 and consists of a set of one or more parameters.

A.1 Horizontal Position AccuracyThe horizontal position accuracy is computed using the projection of the position error on the horizontal plane containing the location target true position (i.e. 2-dimensional projection). The position error is the vector :

- with extremity the location target position reported by the GBLS (and associated timestamp)

- with origin the location target true position at the time the position was sampled by the GBLS

The metrics used to characterise this accuracy are composed of the following quantities:

Mean value of the horizontal position error computed over a specified time interval.

Standard deviation of the horizontal position error computed over a specified time interval.

50th, 67th, 95th and 99th percentiles of the horizontal position error distribution computed over a specified time interval.

These metrics are defined as follows.

Let p be the true position of the location target

Let be the position estimates collected over a specified time interval (N samples), projected on the local horizontal plane containing the location target true position

i is the positioning error vector, defined as i = p - {p*}i . Note that this vector is contained in the local horizontal plane.

The mean value is defined as:

The standard deviation is defined as:

The percentiles, noted x (i.e. respectively 6795 99 ) is defined as the smallest error verifying:

In addition to the above, when the use case considers a moving location target, the following metrics apply:

- the along-track error is the projection of the position error on the axis tangential to the location target trajectory, determined at the location target true position at the time the position was sampled by the GBLS.

- the cross-track error is the projection of the position error on the axis orthogonal to the location target trajectory, determined at the location target true position at the time the position was sampled by the GBLS

Both of these errors are characterised by their mean value, and the 67th, 95th and 99th percentiles values.

The diagram below illustrate these errors.

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Figure 5-1 – Definition of cross-track and along-track errors

A.2 Vertical position accuracyThe vertical position accuracy is computed using the projection of the position error on the vertical axis containing the location target true position.

The metrics are defined in the same way as for Horizontal Position Accuracy above, with “vertical position” substituted for “horizontal position”.

A.3 GNSS Time AccuracyThe GNSS time accuracy is the difference between the true GNSS time (as implemented in the GNSS system timing facility) and the time restituted by the GNSS processor based on the PVT solution.

The metrics used in order to statistically characterise this accuracy are computed as follows :

[m] = [s] c

Where [m] is the timing error expressed in metres, [s] the timing error expressed in seconds, c the speed of light.

The following quantities are used:

Mean value of the restituted GNSS time error computed over a specified time interval.

Standard deviation of the restituted GNSS time error computed over a specified time interval.

50th, 67th, 95th and 99th percentiles of the restituted GNSS time error computed over a specified time interval.

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Align with 5.4

A.4 Time-to-first-fix (TTFF)The time-to-first-fix is the time elapsed between from the location request triggered by the location system (i.e. either from external immediate request, or following a location report trigger), to the position response delivered to the location system external interface.

The metrics used in order to statistically characterise this quantity are composed of the following quantities:

maximum values of the TTFF computed over a specified number of trials.

mean value of the TTFF computed over a specified number of trials.

standard deviation of the TTFF computed over a specified number of trials.

67th, 95th and 99th percentiles of the TTFF computed over a specified number of trials.

A.5 Position AuthenticityThe authenticity performance is characterised by the ability of the system to identify spoofing attempts accurately.

For position authenticity, the metrics to be used are therefore:

Probability of missed-detection in case of spoofing attempt (threat scenario)

Probability of false alarm in case of no spoofing is attempted (fault free scenario)

Mean time to provide position authenticity (latency)

NOTE: Position Continuity is considered in A.11 and Position Availability under A.3.

A.6 PVT Degradation under interference sourcesPVT degradation is measured as increase of the position, speed (and time???) estimation error caused by interference sources.

A.7 Recovery time of normal performance after termination of interference

Considers recovery after front-end saturation.

Includes Pulse, CW and wideband.

Proposed for removal

A.8 GNSS sensitivityInclude acquisition and tracking sensitivity, reference 3GPP.

A.9 Position Integrity (Protection Level)The integrity performance is characterised by:

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Is this relevant?


Clarify text to define how performance is defined

The Position Integrity (Protection Level) expressed in metres

The integrity risk, expressed as the probability that the actual position accuracy exceeds the position protection level under fault-free and faulty modes.

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TS 103 246-3 V0.2.3 (2014-12)37

Annex B (normative):Applicable conditionsThis section describes the conditions applicable to the definition of the performance requirements given in clause 5.. These conditions concern:

the external systems with which the location system interacts.

the operational environments applicable to the location system performance.

the moving target scenario description.

B.1 External Location Systems ParametersB.1.1 GNSS systems parameters

B.1.1.1 GNSS Systems constellation geometry and signal parameters

GNSS systems applicable to the performance specifications are shown below including:

the constellation geometry to be used

signal parameters to be used, in particular the signal modulation parameters, and the minimum received power on ground in nominal conditions.

Table 5-46 – GNSS Constellations parameters

GNSS system System/User interface description

Number of visible satellites [Note 1]

HDOP range

GPS L1C/A [2] Variable 1.6 to 2.5 [tbc]GALILEO OS [1] Variable 1.6 to 2.5 [tbc]GALILEO E5A Variable 1.6 to 2.5 [tbc]

GLONASS [6] Variable 1.6 to 2.5 [tbc]GPS L5 [Note 2] [3] Variable 1.6 to 2.5 [tbc]

GPS L1C [Note 2] [4] Variable 1.6 to 2.5 [tbc]Beidou [7] Variable 1.6 to 2.5 [tbc]

Note 1: Number of satellites for testing will be defined in the Test Specification [….]

Note 2: Single frequency use considered at present

B.1.1.2 GNSS System Time Offsets

If more than one GNSS is used in a test, the accuracy of the GNSS-GNSS Time Offsets used at the system simulator shall be better than [TBC].

B.1.2 SBAS systems parameters

B.1.3 Cellular systems parametersfind a parameter equivalent to HDOP range to fix network properties. See 3GPP specs.

Some location systems rely on only cellular/wifi/bluetooth/DVB for positioning. The following list of standards is applicable for the definition of interfaces with external communication systems.

IEEE 802.11 for WiFi

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IEEE 802.15 for Wireless Personal Area Network (short range wireless)

- IEEE 802.15.1 for Bluetooth

- IEEE 802.15.4a for low rate WPAN

3GPP TSXX;XXX for 2G



[FFS] for 5G

B.2 Operational environmentsThese environments are defined by a list of characteristics:

characteristics of GNSS sensor performance, which are described in clause B.2.1.

characteristics of other sensors performance, which are described in clause B.2.2.

B.2.1 Operational environments definitionTable 5-47 – Operational environments definition

Operational environment

typeMasking conditions Multipath

LevelInterference

levelMagnetic

conditions

Telco beacons

distributionPolar plot Zone Atten

Open Area Open skyx1 0 dB

Null Null NominalRural

distributionx2 >100dB

Urban AreaUrban

Canyonx1 0 dB

High Medium DegradedUrban

distributionx2 >100dB

Asymmetric Area

Asymmetric visibility

x1 0 dB

High Medium DegradedUrban

distributionx2 >100dBx3 15 dB

Note: for all of the above environments, the antenna gain is assumed to be 0dBi.

B.2.2 GNSS-related environment characteristicsThe following characteristics are related to the reception conditions of the GNSS signals.

These reception conditions concern:

GNSS signals masking or attenuation from a terminal perspective, due to obstacles (buildings, walls, trees, windows, vehicles, etc) located on the signal propagation path. This is referred to as “sky attenuation conditions” in the rest of the document

Existence of undesired GNSS signals echoes at terminal antenna input, caused by specular or diffuse reflections, and affecting the performance of the navigation solution. This is referred to as “multipath” in the rest of the document.

Presence of electro-magnetic interference sources in the terminal vicinity, causing an observable increase of noise in the terminal RF chain processing. This is referred to as “interference” in the rest of the document.

NOTE: the above phenomena are considered local contributors to GNSS signals quality. GNSS signal characteristics prior to being affected by these conditions (i.e. ignoring contribution of terminal vicinity, such as direction of arrival (and hence HDOP), received signal power) are assumed to be in line with Interface Control Documents of each of the considered GNSSs (see [1], [2], [3], [4], [5], and [6])

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B.2.2.1 Sky Attenuation Conditions

Applicable sky conditions are as follows.

Figure 5-2 - Sky attenuation conditions

A sky plot provides:

the area of the sky above the receiver being affected by total signal masking. When Satellite azimuth and elevation coordinates (from terminal point of view) falls into these area, GNSS signal is considered blocked.

the area of the sky above the receiver being affected by partial signal masking. When Satellite azimuth and elevation coordinates (from terminal point of view) falls into these area, GNSS signal is considered attenuated. The amount of this attenuation is defined for each operational environment.

NOTE: several distinct areas can be defined for a single operational environment.

Typical sky attenuation conditions are defined here below

Remove elevation from all. Replace by table simplifying all.

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TS 103 246-3 V0.2.3 (2014-12)40

Figure 5-3 - Open Sky plot. Table 5-48 – Open sky definition

ZoneElevation range

(deg)Azimuth range

(deg)A 0 – 5 0 – 360

Background Area out of Zone A

Figure 5-4 – Light masking plot. Table 5-49 – Light masking definition

ZoneElevation range

(deg)Azimuth range

(deg)A 0 – 5 0 – 360

B 5 - 30 210 – 330

C 5 - 30 30 - 150

Background Area out of Zones A, B, C

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Make x values clear

Figure 5-5 – Dense masking plot Table 5-50 – Dense masking definition

ZoneElevation range

(deg)Azimuth range

(deg)A 0 – 5 0 – 360

B 5 – 20 210 – 330

C 5 – 20 30 - 150

D 20 – 40 30 - 150

E 20 – 40 210 – 330

Background Area out of Zones A, B, C, D, E

Figure 5-6 – Urban canyon plot. Table 5-51 – Urban canyon definition

ZoneElevation range

(deg)Azimuth range

(deg)A 0 – 5 0 – 360

B 5 – 60 210 - 330

C 5 – 60 30 - 150


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TS 103 246-3 V0.2.3 (2014-12)42

Figure 5-7 – Asymmetric visibility plot Table 5-52 – Asymmetric visibility definition

ZoneElevation range

(deg)Azimuth range

(deg)A 0 – 5 0 – 360

B 5 - 60 30 – 150

C 10 – 60 230 - 310


B.2.2.2 Multipath Scenario

The multipath model applicable to the performance specification is described below.

Doppler frequency difference between direct and reflected signal paths is applied to the carrier and code frequencies. The Carrier and Code Doppler frequencies of LOS and multi-path for GNSS signal are defined in the table below.

Table 5-53 – Multipath model components

Initial relative Delay [m]

Carrier Doppler frequency of tap [Hz]

Code Doppler frequency of tap [Hz]

Relative mean Power [dB]

0 Fd Fd / N 0X Fd - 0.1 (Fd-0.1) /N Y

NOTE:Discrete Doppler frequency is used for each tap.

X, Y and N depend on the GNSS signal type. In addition, Y depends on the intensity of multipath faced in the operational environments. N is the ratio between the transmitted carrier frequency of the signals and the transmitted chip rate.

The initial carrier phase difference between taps shall be randomly selected between 0 and 2. The initial value shall have uniform random distribution.

The table below provides the parameters values of 3 levels of multipath intensity, from low to high.

Table 5-54 – Multipath model parameters

Multipath level Low Med HighSystem Signals X [m] Y [dB] Y [dB] Y [dB]

GalileoE1 125 [tbd] -4.5 [tbd]

E5a 15 [tbd] -6 [tbd]E5b 15 [tbd] -6 [tbd]

GPS/Modernised GPS

L1 C/A 150 [tbd] -6 [tbd]L1C 125 [tbd] -4.5 [tbd]L2C 150 [tbd] -6 [tbd]L5 15 [tbd] -6 [tbd]

GLONASS G1 275 [tbd] -12.5 [tbd]G2 275 [tbd] -12.5 [tbd]

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Table 5-55 – Ratio between Carrier Frequency and Chip Rate

System Signals N

GalileoE1 1540

E5a 115E5b 118

GPS/Modernised GPS

L1 C/A 1540L1C 1540L2C 1200L5 115

GLONASS G1 3135.03 + k 1.10G2 2438.36 + k 0.86

Note: Parameter “k” above is the GLONASS frequency channel number.

B.2.2.3 Electro-magnetic Interference

The EMI model applicable to the performance specification is described below.

Interference conditions are modelled by the total noise power density after correlationN X , Ic

, . It is derived from the interference source spectral characteristics according to the following formula:

N X , Ic =∫

f c−BW X

2

f c +BW X

2 N I (f )⋅PG X ( f )⋅df

where

X stands for considered GNSS signal (e.g. Galileo E5a, GPS L1C …)

f c is the carrier frequency of the considered GNSS signal X

BW X is the GNSS sensor filtering bandwidth of the considered GNSS signal X

N I ( f ) is the external noise power density at the antenna level,

PG X ( f ) is the spreading gain enabled by the receiver correlator while processing signal X

In the frame of this technical specification, three levels of impact of the interference environments are considered, from low to high.

Table 5-56 – Interference levels

EMI level NILow -200 dBW/HzMedium -195 dBW/HzHigh -185 dBW/Hz

B.2.3 Additional environment characteristicsFurther to the above environment characteristics, addition characteristics are defined. They are relevant to the specification of performance for system embedding technical enablers other than GNSS sensor.

B.2.3.1 Telecommunication beacon deployment

According to [7], location systems might embed telecommunication sensors which enable the provision of measurements participating to the navigation solution. This sub clause defines additional environmental characteristics relevant to this type of sensors.

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Depending on the claimed compatibility of the location system under test, the beacon deployment(s) applicable to the present performance specification shall be as follows (one or several clauses applicable). Applicability is defined in [i.3].

B.2.2.1.1 Cellular telecommunications base stations characteristics and deployment

Relevant standard reference, providing the Base Station (BS) signal specification is provided in clause B.1.3.

B.2.2.1.1.1 Base stations deployment height

[TBD]

B.2.2.1.1.2 Base stations deployment density

[TBD]

B.2.2.1.2 Wi-Fi access points characteristics and deployment


B.2.2.1.2.1 Access points deployment height

[TBD]

B.2.2.1.2.2 Access points deployment density

[TBD]

B.2.2.1.3 Blue-tooth transmitters characteristics and deployment


[TBD]

B.2.2.1.4 DVB transmitters characteristics and deployment

Relevant standard reference for the Base Station (BS) signal specification is provided in clause B.1.3.

B.2.2.1.4.1 Transmitters deployment height

[TBD]

B.2.2.1.4.2 Transmitters deployment density

[TBD]

B.2.2.1.5 Microcell (5G) transmitters characteristics and deployment

For further study.

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B.2.3.2 Interference source definition

list the interference sources considered for “EMI robustness” and “EMI Localisation Accuracy”, for which the simplistic model of section B.2.1.3 is not suited

interference characteristics to be specified: received power, frequency, spectral shape (tbc), temporal shape (tbc).

The table below specifies the jamming signals used as interference sources for the jamming scenarios considered in clauses 5.7 and 5.8. The definition of the jammer is based on the interference models of some PPDs (Personal Privacy Devices) as described in literature.

The jamming signal is a FM modulated signal with a sine waveform with a frequency of the waveform of the FM interfering signal equal to 50 kHz and a deviation depending on the interference bandwidth (10 and 20 MHz).

Table 5-57 – Interference source definition

Class Centre Frequency

Bandwidth Sweep time Peak [dBm]

J#1: Chirp signal with one saw-tooth function

1575.42 MHz 20 MHz 20 µs -9.6

J#2: Chirp signal with one saw-tooth function

1575.42 MHz 10 MHz 20 µs -9.6

Note. The bandwidth is considered as a 3 dB bandwidth around the specified centre frequency, i.e. the first case in Table 5-57 (20 MHz) corresponds to the range of frequencies [1565.42, 1585.42] MHz.

The actual power of the jamming source accounts for the free space propagation losses (as described in Figure 5-8) and the initial jammer power reported in Table 5-57. Besides, the relative Doppler is negligible if compared to the frequency range swept by the jammer.

Figure 5-8 – Free space propagation loss with respect to the jammer distance

B.2.3.3 Magnetic conditions

[TBD]

ETSI

-150 -100 -50 0 50 100 150

-80

-75

-70

-65

-60

-55

-50

-45

X: 3.003Y: -45.94

Distance [m]

free

spac

e pr

opag

atio

n Lo

ss [d

B]

Jammer Overtaking

X: 100Y: -76.39

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B.3 Moving Target Scenario The diagram below describes the reference trajectory used in clause 5.

Point {0;0;0} is used as reference of the local coordinate system (X,Y), defining local horizontal plane.

Figure 5-9 – Location target trajectory

Table 5-58 – Trajectory parameters

Parameter Value (m) – outdoor Value (m) – indoorX 1440 45.6Y 940 37.6R 20 1

The diagram below provides the location target speed profile, when travelling trajectory above.

Figure 5-10 – Location target speed profile

ETSI

X

Y

A1

A2

A3

A4

A5A6A7

A8

A12

A11

A10

A9

A16A15A14A13

R

Y

A8{0;0;0}

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Parameters X, Y, R are defined here, d1, D2, v1, v2, v3 are defined in section 5.1 through 5.7. Could we define them in the same location ?

Specific values of parameters d1, D2, v1, v2 and v3 are defined for each Performance Feature in clause 5.

Annex C (normative):Threat Scenarios for Authenticity and Integrity FeaturesC.1 Authenticity Threat ScenariosThis clause describes the threat scenarios used for the definition of the performance requirements for authenticity features.

C.1.1 Threat scenariosAll the threat scenarios define spoofing attempts to the GNSS sensor of the positioning module. Such spoofing attempts broadcast intentional RF interference, with a structure similar to authentic GNSS signals, in order to deceive the GNSS sensor into estimating erroneous pseudo-ranges and computing false PVTs.

C.1.1.1 Scenario pre-conditions

The following pre-conditions apply to the location system:

location-related data of the location target are available;

all tracked GNSS signals are authentic.

C.1.1.2 Scenarios chronology

All the considered scenarios follow the sequence of events depicted in the figure below:

Figure 5-11 - Sequence of events associated to the threat scenarios

Where:

T0 is the time of start of the scenario;

Ts is the time of start of the threat

Te is the time of the end of the scenario

C.1.1.3 Scenario parameters

The scenarios are defined by the following list of parameters

Attack classification: it defines classes of spoofing attempts, based on the method used to force the GNSS sensor to track the counterfeit GNSS signals;

Total Spoofing Power (TSP): the signal power of the sum of counterfeit GNSS signals, received at the GNSS sensor antenna, which is assumed isotropic.

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Misleading information category: determines the type of misleading information based on the impact of the spoofing attack on the data at the output of the GNSS sensor.

Target movement: if the target moves, it provides its trajectory and dynamics

The following sub-clause defines each of these parameters.

C.1.1.3.1 Attack classifications

Two main classes of attacks are identified based on the method used to force the GNSS sensor to track the fake GNSS signals. Several spoofed signals can be generated. For both classes it is considered that the spoofed GNSS signal(s) is (are) radiated from a single antenna.

Direct spoofed GNSS signal introduction

In this method, the counterfeit GNSS signals are generated and radiated towards the GNSS sensor without considering the overall context (i.e. GNSS constellation geometry, current GNSS time, and GNSS sensor position).

In this case, in order to force the GNSS sensor to track spoofed spreading codes, a signal outage of the authentic GNSS signals should be induced between T0 and Ts (e.g.: through a jamming attack that breaks the tracking of authentic signals). At Ts, the false GNSS signals are radiated towards the GNSS sensor, and the power received by the GNSS sensor is in line with the TSP specified.

Shadowed spoofed GNSS signal introduction

In this method, the counterfeit GNSS signals are generated and radiated towards the GNSS sensor in a way that the correlation peak associated to the counterfeit signal rises in the shadow of the correlation peak of real signal. Varying the relative delay between the authentic and counterfeit spreading codes and increasing the power of the counterfeit GNSS signals, the GNSS sensor is forced to lose the tracking of the authentic spreading code and synchronises its local code with the counterfeit spreading code. Therefore, it means that GNSS constellation geometry, current GNSS time, and GNSS sensor position are known by the spoofing source in order to estimate the authentic code delay and Doppler frequency at the target GNSS sensor. The counterfeit signal is a false copy of that actually in view at the moment of the attack.

The figure below illustrates this concept on the correlation domain, where the correlation peaks associated to authentic signals are green, correlation peaks due to counterfeit signals are in purple and the composite correlation peaks are in blue.

Figure 5-12 - Effects of shadowed spoofing on correlation functions

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C.1.1.3.2 Total spoofing power

The total spoofing power (TSP) is the signal power of the sum of counterfeit GNSS signals received at the GNSS sensor antenna, which is assumed isotropic so that all signals are weighted equally.

It is defined as:

[dBW]

where is the power of the ith counterfeit signal generated by the spoofing device.

The TSP is variable for each scenario, and used as a metric to measure the location system authenticity performance.

C.1.1.3.3 Misleading information category

The spoofing attacks can cause three types of misleading information at GNSS sensor:

erroneous PSR measurement;

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erroneous time estimates;

erroneous estimates of the position (for both static of moving scenario).

The following error models, namely unit step and ramp functions multiplied by constant coefficients, are used for each of the above misleading information.

Figure 5-13 - Threat scenario error models

These models are applied for each type of misleading information according to the table below, where:

is a constant coefficient that multiply the unit step function, starting at ;

b is a constant coefficient that multiply the ramp function, starting at ;

Table 5-59 - Misleading information model parameters

Misleading information Error unit a unit b unitPSR measurement m m m/s

time estimates s s s/sposition estimates (1) m m m/s

NOTE (1): The position error is measured on the across-track axis.

The models parameters, either for the unit step function and the ramp, are variable for each scenario, and used as a metric to measure the location system authenticity performance.

C.1.1.3.4 Location target movement

For use cases where the location target is moving, the following trajectory shall be used.

Figure 5-14 - Threat scenario trajectory

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Point A is crossed at T0, point B is crossed at Te. The location target speed shall be uniform and equal to 50 km/h on the entire trajectory (see B.3).

C.1.2 Threat scenarios for moving targetsThe threat scenarios listed in the table below are defined for moving targets. Trajectory defined in clause C.1.1.3.4 applies. Pre-conditions defined in clause C.1.1.1 apply.

Table 5-60 - Threat scenario for moving targets

Scenario identifier

Attack class

Number of spoofed

PRNs

TSP range(dBW)

Misleading information

category

Error model Model value range

M-1 Shadow All(1) [-144.5 -140.5] Estimated Time Ramp [2-20] ns/s(2)

M-2 Shadow 4 [-148.5 -144.5] PSR measurement Ramp [3.5-6.5] m/sM-3 Shadow 4 [-148.5 -144.5] Estimated Position Ramp [1-7.5] m/s(2)

M-4 Direct 4 to 12(3) [-142.5 -137.7] Estimated Time step function [5-60] sM-5 Direct 4 to 12(3) [-142.5 -137.7] Estimated Position step function [0.1-10] km

Note (2): The model value ranges for the estimated time and position assume HDOP compliance with Table 5-46.

Note (3): At least 4 PRNs of those in view should be spoofed to perform the M-4 and M-5 spoofing attacks;

C.1.3 Threat scenarios for static targetsThe threat scenarios listed in the table below are defined for static targets.

Pre-conditions defined in clause C.1.1.1 apply.

Table 5-61 - Threat scenario for static target

Scenario identifier

Attack class

Number of spoofed PRNs

TSP range(dBW)

Misleading information

category

Error model Model value range

S-1 Direct [4 12](1) -142.5 to -137.7 Estimated Time step function 5-60 sS-2 Direct [4 12](1) -142.5 to -137.7 Estimated Position step function 0.1-10 kmS-3 Shadow All(2) -158.5 to -153,5 Estimated Time Ramp 2-20 ns/s(3)

S-4 Shadow 1 -158.5 to -153,5 PSR measurement Ramp 3.5-6.5 m/sS-5 Shadow 1 -158.5 to -153,5 Estimated Position Ramp 1-7.5 m/s(3)

Note (1): At least 4 PRNs of those in view should be spoofed to perform the S-1 and S-2 spoofing attacks;

Note (2): The number of spoofed PRNs is equal to the number of the satellites in view;

Note (3): The model value ranges for the estimated time and position assume HDOP compliance with Table 5-46.

C.2 Integrity threat scenariosFor failure modes of GNSS systems see DO-208

Annex D (informative): BibliographyThe annex entitled "Bibliography" is optional.

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It shall contain a list of standards, books, articles, or other sources on a particular subject which are not mentioned in the document itself (see clause 12.2 of the EDRs http://portal.etsi.org/edithelp/Files/other/EDRs_navigator.chm).

It shall not include references mentioned in the document.

History

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http://portal.etsi.org/edithelp/Files/other/EDRs_navigator.chm