smr technical description
TRANSCRIPT
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Terma A/S, DK-8520 Lystrup, Denmark060307 9:10 SMR Technical description
Technical Description
Airport
Surface Movement Radar System
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CONTENTS
1 SCOPE...............................................................................................................................................4
2 INTRODUCTION................................................................................................................................4
2.1 Careful Antenna Siting ................................................................................................................4
3 PRODUCT RANGE............................................................................................................................5
4 SYSTEM DESCRIPTION AND DESIGN ...........................................................................................6
4.1 Basic available systems ..............................................................................................................64.2 Dual System Configuration..........................................................................................................7
5 MAIN FEATURES............................................................................................................................10
5.1 Profiles.......................................................................................................................................10
5.2 Remote Control and Monitoring ................................................................................................105.3 RTCM........................................................................................................................................115.4 Modular Unit Structure ..............................................................................................................11
6 FUNCTIONAL DESCRIPTION.........................................................................................................13
6.1 Transceiver Configurations .......................................................................................................136.2 Transmitter ................................................................................................................................146.3 Receiver ....................................................................................................................................146.4 Motherboard and Power assembly ...........................................................................................176.5 Transceiver Controller...............................................................................................................196.6 Radar Signal Distribution...........................................................................................................216.7 Mains Distribution......................................................................................................................216.8 Antenna interface ......................................................................................................................22
6.9 External connections .................................................................................................................23
7 ADD-ON FUNCTIONS.....................................................................................................................23
7.1 Built-in antenna motor control ...................................................................................................237.2 Signal Processing......................................................................................................................247.3 Video Processor........................................................................................................................247.4 External Bi-Directional Couplers ...............................................................................................267.5 Dehydrator.................................................................................................................................26
8 TECHNICAL SPECIFICATIONS......................................................................................................27
8.1 Transmitter ................................................................................................................................278.2 Receiver ....................................................................................................................................288.3 Antenna Interface......................................................................................................................308.4 Waveguide Switch Control Output ............................................................................................318.5 External Trigger (Sync) Input ....................................................................................................318.6 Auxiliary I/O ...............................................................................................................................318.7 Data communication..................................................................................................................318.8 Radar Signal Distribution...........................................................................................................32
9 ADD-ON SPECIFICATIONS............................................................................................................33
9.1 Built-in Antenna motor control...................................................................................................339.2 Video Processor........................................................................................................................339.3 Static Clutter Map (Option)........................................................................................................34
10 ANTENNA SYSTEM (OPTION) ...................................................................................................36
10.1 Product Characteristics .............................................................................................................3610.2 The Scanner..............................................................................................................................36
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10.3 Turntable & RF Feed.................................................................................................................3610.4 Heater and Sensors ..................................................................................................................37
11 SPECIFICATIONS........................................................................................................................37
11.1 Main data...................................................................................................................................3711.2 Horizontal Radiation Pattern .....................................................................................................3811.3 Elevation Patterns .....................................................................................................................39
11.4 RF Power handling....................................................................................................................3911.5 RF Flange..................................................................................................................................3911.6 Colour Scheme..........................................................................................................................39
12 WEIGHT & MECHANICAL DIMENSIONS...................................................................................39
12.1 Forces acting on the antenna....................................................................................................4012.2 Environmental Capabilities and Constraints .............................................................................41
13 FUNCTIONAL CAPABILITIES.....................................................................................................42
13.1 Target Detection........................................................................................................................4213.2 Coverage...................................................................................................................................4413.3 Performance - Resolution..........................................................................................................47
14 AVAILABILITY AND MAINTENANCE.........................................................................................4814.1Availability, Reliability, and Maintainability Analysis4814.2 Maintenance Schedule..............................................................................................................4914.3 Maintenance Equipment............................................................................................................50
15 DOCUMENTATION......................................................................................................................51
15.1 Instruction booklet .....................................................................................................................5115.2 CD-ROM....................................................................................................................................51
16 ENVIRONMENTAL SPECIFICATIONS.......................................................................................52
16.1 Safety ........................................................................................................................................52
17 WEIGHT AND DIMENSIONS.......................................................................................................53
ANNEX 1 - ABBREVIATIONS................................................................................................................54
ANNEX 2 - INDEX ...................................................................................................................................55
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1 SCOPE
This document specifies the capabilities of the proposed stationary Terma SCANTER X-Band RadarSensor System for use in Airports as the runway Airport Surface Movement Radar sensor system.
This document is a comprehensive description of the complete radar sensor system proposed to fulfilthe operational requirements
2 INTRODUCTION
Safe and reliable operation is of high importance and each individual SCANTER product is designedbearing that in mind. Components are de-rated to ensure long lifetime, and numerous fall back modesexist as an integral part of the design. Redundancy and fall-back modes are furthermore designed tokeep single point failures simple and do additionally include full redundant parallel processing.
The transmitter, receiver, and signal processing technology is configured to ensure optimum perform-ance of the SCANTER Radar Sensor Systems for continuous operation in all weather conditions.
The aim of the SCANTER 2001 Transceiver is to provide a clean picture of on-ground movements
given any weather conditions for Airport Surface Movement applications.The system is therefore characterised by high resolution, a wide receiver dynamic range, noise reduc-tion facilities, built-in test equipment, and the ability to perform remote servicing activities.
The SCANTER 2001 Transceiver product range supports 6 system configurations; ranging from a basicsingle Transceiver unit to a Dual Redundant Frequency Diversity configuration.
This System Specification describes the dual configuration with various options including the novel 21Circular Polarised CP-I antenna.
2.1 Careful Antenna Siting
The most important radar sensor performance requirement for an airport is the siting of the radar an-tenna. The Air Traffic Control Tower is often the preferred location for the radar. Terma has extensiveexperience in radar location evaluation and selection. In order to get the optimum performance out of
the radar system a site survey is proposed in order to address among others the following items:
Expected shadow areas for possible radar locations
Expected multiple reflections from radar locations
Coverage/obscuring by static objects
Resolution and detection
Target aspect
Obscuring by dynamic objects (line-up)
Location of multipath returns
Close range coverage/look-down angle
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3 PRODUCT RANGE
The SCANTER Radar Sensor Systems for airport surface movement detection applications are basedon a modular concept, specified and build for world-wide use. The basic radar systems will either be:Single, Dual or Diversity systems.
Antennas can be selected from a range of Terma slotted Waveguide or from other manufacturer. Espe-
cially for airport applications circular polarised are recommended.
RxTx units are modular, configured by insertion of individual modules in a common housing includingreceiver, modulator, power supply, communication, control, cooling, and protection against electromag-netic interference and overload (fuses etc)
Peripheral units such as maintenance displays and switch units are, to the extent possible, configuredfor use throughout the product line, independent of the actual configuration.
The features listed in Table 3.1 - Product range, are included in Terma's production line for airport sur-face movement radar applications.
The SMR product range is in continuous development and Terma reserves the right to include addi-tional features within the products and in the referenced documents, as they become available.
The following table illustrates the complete available Terma product range. The specific system pro-posed for the Brussels project is emphasised specifically. The actual configuration is based on thecharacteristics described in following sections of this document.
DESCRIPTION SINGLE
DUAL
Redundant RxTx
DIVERSITY
RedundantRxTx
Antennas
21 SWG Fan beam Circular polarised Option Option Option
21 SWG Inv csc2
Circular polarised Option Option Proposed
Antenna Control Units
Motor Control (Inverter) Option Proposed Option
RxTx Units with
RS-422 communication channels (eachRxTx unit)
3 3 3
Automatic Channel Switch Over on Fail-ures
N/A Standard Standard
Frequency Diversity N/A N/A Standard
40 ns PW @-3dB Standard Standard Standard
Sector Tx + 3 channel signal distribution Standard Standard Standard
Static Clutter Map and Blanking Map Option Option Option
Built-in power and NF meter Option Standard Standard
Digital Video Processing Option Proposed Standard
External Bi-Directional Couplers Option Proposed Option
Selection of transmitting frequency between
9.170 GHz 30 kW magnetron Option Option Standard(Unit#1)
9.375 GHz 25 kW magnetron Standard Option N/A
9.410 GHz 25 kW magnetron Standard Proposed N/A
9.438 GHz 30kW magnetron Option Option Standard(Unit#2)
9.490 GHz 30 kW magnetron Option Option N/A
Installation and Training
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DESCRIPTION SINGLE
DUAL
Redundant RxTx
DIVERSITY
RedundantRxTx
On plywood board Standard Standard Standard
Installation On site Option Option Option
Maintenance and System Training Option Option Option
System Control, Remote and Local
Remote/Local control BITE Service SW Option Option Proposed
Open protocol Standard Standard Standard
LAN access (TCP/IP) incl. HMI clients Standard Standard Standard
Miscellaneous
3 Years Warranty Option Option Option
Active Dehydrator Option Option Option
Full support Standard Standard Standard
Castell Interlock System Option Option Proposed
Table 3.1 - Product range, SMR
4 SYSTEM DESCRIPTION AND DESIGN
4.1 Basic available systems
Safe and reliable operation is of high importance for the application and each individual SCANTERproduct is designed bearing that in mind. Components are selected with care and de-rated to ensurelong lifetime, and numerous Fallback modes exist as an integral part of the design.
Redundant systems are furthermore designed to keep any possible single point of failure as simple aspossible.
High antenna gain and Circular Polarisation is required in order to obtain sufficient range coverage andsufficient rain penetration. The radar return - and thus the requirement to dynamic range - increasestwice as much as additional antenna gain (in dB).
To reduce the effects due to bounces from the ground surface in heavy precipitation, the radar sensorsystem may include frequency diversity. In this mode both RxTx units are operating simultaneously,each transmitting on an individual frequency ensuring de-correlation of return clutter reducing targetfluctuations and thereby increasing delectability of small targets. Experience shows that at least a 10dBsignal-to-clutter improvement can be expected.
The transmitter frequencies available have been selected to comply with world-wide ITU regulations forfrequency allocation, and for diversity systems to obtain sufficient spread in the spectrum in order to de-correlate signals from direct clutter return and from bounces off the ground as much as possible.
The receiver-transmitter unit acts as the central part of the radar system as it performs control of thecommunication between the units and generates the basic radar signals.
The units are all equipped with computer-controlled built-in test equipment (BITE). This may be interro-gated from a local Personal Computer (PC) with control and monitoring software. The recording ofBITE messages will store all fault messages when they occurred in a database.
The RxTx units are prepared for use in 3 basic sensor system configurations:
Single systems characterised by the RxTx having complete inherent system functionalityincluding control of antenna motor power. The system is prepared for later update todual configuration.
Dual redundant systems with all functions duplicated, except antenna motor power con-trol.
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Dual diversity systems, based on the dual redundant system configuration, and addi-tionally having signals cross coupled prior to diversity and video signal processing. Inthis way will both RxTx units at anytime process and provide identical video signals atthe output for redundant distribution.
The requirements are specifically focusing on:
Resolution
Detection in all weather conditions Redundancy and uninterrupted operation
These can be fully met with a Dual channel configuration with 4-pulse non-coherent pulse integrationand with an Inverted csc2 circular polarised high gain antenna.
A frequency Diversity configuration will however increase the long-range detection capability of smalltargets in heavy precipitation.
4.2 Dual System Configuration
The proposed dual system facility includes digital processing provided by a add-on module and addi-tional service features such as an external waveguide switch that easily can route the RF into build indummy loads instead of into the antenna. This provides the ability having the standby channel in Hot-
Stand by as only one channel at a time can be connected and transmitting into the antenna.The dummy load is rated for max 50W continuously and as no more than maximum 10W averagepower is dissipated will any temperature rise be insignificant.
The system has Fallback possibilities so that each RxTx can operate independently as a normal single-frequency system in case of any system failures. This means that one channel can be taken out of ser-vice without having an impact on the other channel.
A pilot voltage separately powers the Controller Board in the RxTx unit, maintaining communication andBITE features, if other parts of the unit become faulty.
Each of the RxTx units can operate independently of the other, controlled manually via the build-in con-trol panel in each RxTx unit or by use of remote controlling features.
Control of the antenna is provided via parallel diode protected lines, one from each RxTx, maintainingoperation if one of the RxTx becomes faulty.
The two encoders are powered independently from each RxTx unit.
In the dualised architecture can one channel completely be taken out of for maintenance service with-out invalidating the coverage capabilities stated later herein.
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Modules/features:
Motherboard and Power Supply Type 1
Modulator 2 * 25-30 kW direct drive
Magnetron 2 * 9.410 GHz X-band
Receiver 2 * X-band 9-3-9.5 GHz
Processing Video Processor
Power inlet Mains DistributionAdd-on: Motor Controller 2.2 kW, 380-440V, 3-phase
Externally mounted compo-nents
WG switch + dummy load + WG parts
Pre-installation Incl. interconnection cables between units, fittingsetc
Figure 4.1: Dual System
4.2.1 Single Point Failures
4.2.1.1 RxTx Units
No single failure can cause power down of the whole dual RxTx system and hence complete loss ofdata for the following video processing.
4.2.1.2 Antenna system
The following single points of failure exists in the antenna system:
Antenna subsystem incl. motor
Frequency converter (Motor drive)Breakdown on one of these components will cause a temporarily non-operational,-/working system.
The Terma antenna turning motor is equipped with two temperature sensors that are constantly moni-tored by the RxTx BITE system. One is activated at 130
owhich issues a BITE warning and the other at
150o
Celsius forces the motor and transmission to switch Off automatically. Normal operational modewill be restored automatically when the temperature has decreased sufficiently.
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4.2.2 Built-in Monitoring
The micro-controllers residing on each module performs BITE in the form of memory checks etc. duringstart up as well as continuous monitoring of voltages, currents, transmitted power, receiver noise figure,temperature and signal activity. Warnings and errors messages are issued for local and remote use.The individual BITE measurements can be accessed continuously.
If a monitored function turns out to be outside the specification, a warning or a fault message is issued.
The radar may even go into fallback mode where reduced performance is the result i.e. an automaticchannel switch can take place.
Overheating at one or more of the temperature test points will result in a warning message and criticaloverheating will result in automatic switch down.
Radar-on time, magnetron-on time, performance parameters and the latest error messages are storedin non-volatile memory for read out at any time. This provides tools for determination of magnetron endof life criteria and other maintenance related use.
Monitoring of communication between nodes inside the radar system is done to ensure that all nodesare constantly participating in the network.
The modulator is monitored for internal voltages, currents and temperatures. Included is the High Volt-age for the magnetron, peak current in the magnetron and mean current in the power supply part of the
modulator. Furthermore, the temperature inside the modulator is monitored.
The receiver monitors forward power level, receiver noise, AFC-voltage, LO-voltage and other relevantinformation concerning performance. A reference source allow the noise figure to be constantly calcu-lated based on the receiver noise measurements
Trigger monitoring mainly consists of checking that triggers change state within a time interval at vari-ous inputs and outputs.
Video signals are checked in the same way as triggers. The signals are fed to analogue comparatorsthat are checked for change of state within time intervals.
Reading status from motor, gear and auxiliary inputs monitors the antenna.
All data is available via the CAN Bus connecting to the individual modules.
The Supply Monitor monitors all voltages generated by the Power Supply. Information about the stateof this assembly is also available.
The Transceiver Main Controller provides serial communication and a LAN channel for remote access.A panel with alphanumeric display and input keys gives full access for local service and set-up.
4.2.3 Fall Back Modes
The system has Fallback possibilities in case of a failure situation is detected.
A pilot voltage separately powers the Controller Board in the RxTx unit, maintaining communication andBITE features, if other parts of the unit become faulty.
Each of the RxTx units can operate independently of the other, controlled manually via the build-in con-
trol panel in each RxTx unit or by use of remote controlling features.
Control of the antenna is provided via parallel diode protected lines, one from each RxTx, maintainingoperation if one of the RxTx becomes faulty.
By configuration, the user can select the system automatic reaction in case of a system failure detectedby the BITE system. An automatic channel change can take place if the following are fulfilled:
The Automatic Switch over function is enabled by the user
A failure is recognised and reported by the BITE systemThe function has to be re-enabled by the user whenever an automatic switching has taken place. Thisis to prevent the system from switching continuously between the units in case for multiple failures.
Loss of communication does not affect the operation. The RxTx units proceed in the latest state beforethe loss of communication.
Video is defective during the time it takes to detect and enter the Fall Back mode.
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Performance Decrease detection in one of the RxTx units (i.e. failure detection on receiver noise figureor RF transmitter power level), will also result in automatic switch between the channels.
5 MAIN FEATURES
The SCANTER 2001 Transceiver concept features:
Modular open-end system architecture High system performance, including a low noise, high dynamic range receiver
Advanced signal processing
Easy operation due to Predefined settings (Profiles)
Remote control
High reliability entailing low maintenance costs and longlife Built-in Test Equipment (BITE) including output power and Noise Figure (NF) measure-
ment
Preparations for integration of future modules/functions
5.1 Profiles
Profiles are predefined parameter sets used to set optimal transmitter and receiver performance ac-cording to varying weather conditions or specific operational demands. Thus, the Profiles allow the op-erator to adjust the radar system transmission mode and/or receiver processing in a fast and reliableway.
On the operator display each Profile is given a reference or a nomenclature which uniquely identifiesthe environmental condition or operational mode.
Furthermore, the Profiles eliminate the risk of maladjustment of the radar. And the operator need notacquire detailed knowledge about radar characteristics and meaning as such.
5.2 Remote Control and Monitoring
LAN or serial RS-232/422 communication provides Remote Control of the Transceiver (and antenna)by:
A Personal Computer (PC) equipped with the Remote Transceiver Control and Monitor-ing software tool (RTCM)
A dedicated Remote Control software package as part of large system solutions
System specific softwareThe RTCM is a user-friendly Windows-based tool, specifically developed for PC and compatibles. De-pendent on the Add-on modules included in the actual Transceiver, the RTCM assembles all the func-tions and features necessary to perform advanced control, parameter setting and BITE monitoring. Per-formance parameters and the latest errors are stored in non-volatile memory in the SCANTER 2001Transceiver and may be accessed remotely for detailed analysis and assessment.
5.2.1 Time Synchronisation (option)
The time synchronisation to other systems is achieved by means of a NTP Client SW (WinSNTP) whichwill be running on the LOCAL RTCM platform where the RTCM Server is running i.e. the computer lo-cated next to the RxTx system.
WinSNTP is software for the Windows family of operating systems and synchronises the local PC clockto a source of accurate time such as the TSS-100 or any other suitable NTP server. The IP-address ofthe server has to be specified and then will the application on a regular basis poll the server for correcttime and set the PC clock accordingly.
All BITE-messages will be appended the BITELOG file and will be time stamped using the PC-clock.Further all user actions will also be listed together with proper time-stamp.
This enables complete history track of all changes of settings by the user such as a log of all occur-rences of failures.
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WinSNTP also operates as a server itself for use in closed network environments where synchronisa-tion of all computers to the same time is the requirement rather than reference to an accurate timesource.
5.3 RTCM
The RTCM system is client-server based, such that remote operation by several clients is possible. The
interface to the server is configurable (at installation time) such that both remote sessions via LAN andmodem/serial connections are possible.
PC/Windows -
Service PC
Tranceiver
RTCM
ServerSerial Line
RTCM
Client as
Service
Display
LAN
Connection
Remote PC /
Windows
RTCM
Client
Remote PC /
Windows
RTCM
Client
Dial-in modem line
Communications
network
Figure 5.1: RTCM System Architecture. Software modules are shown with rounded corners, andhardware modules with sharp corners.
5.4 Modular Unit Structure
The SCANTER 2001 Transceiver is based on plug-in modules and embedded software. Each moduleis a line-replaceable unit (LRU).
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Modulator
X-bandReceiver
Mains Distribution
Radar Signal Distribution
BlowerAssy
Motherboard andPower Assembly
Controller andSignal Processing Modules
Magnetron
Figure 5.2: Modules of the SCANTER 2001 Transceiver
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6 FUNCTIONAL DESCRIPTION
6.1 Transceiver Configurations
Each Transceiver is configured with hardware and software for the specific application before shipment.
The unit structure is, however, identical with the signal flow illustrated in Figure 6.1
Radar Signal
Distribution
CanBus
Video ProcessorSCM
Transceiver
Controller
+1Vanalog
vided
Mains
Distribution
Antenna
Motor
Control
Exttrigger
Ext(slow)CanBus
RS232/422
LAN
1or3PhaseMains
ReceiverTransmitter
Power and Motherboard
assembly
AntennaandWG
switchinterface
AnalogVideos
andtriggers
Azimuthsignals
DigitalVideos
Syncronisationand
handshakewithother
transceiver
Safetyloops
AuxillaryI/O
AnalogVideo
Scanter 2001 Transceiver
Figure 6.1: Simplified block diagram
6.1.1 Hardware:
The SCANTER 2001 Transceiver consist of a shock and vibration protected EMC-tight housing con-taining the following modules:
High power (25 kW) modulator with programmable Pulse Width (PW) modulator
X-band magnetrons featuring standard and special frequencies
X Band receiver
Motherboard and Power Assembly, including crate for the Transceiver Controller andplug-in processing modules
Transceiver Controller
Video Processing (VP) for advanced signal processing functions on Single Frequency
Static Clutter Map (SCM) for airports (Option)
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Radar Signal Distribution providing dedicated interfaces, special connectors and specialinterface functions
Mains power supply and antenna safety circuits
Motor control (3-phase mains input)A high-speed CanBus provides internal communication between the modules.
6.1.2 Software
Each module (LRU) is a self-contained unit with control, set-up and monitoring performed by a built-inmicro controller.
The Transceiver Controller feeds Profiles and operational commands to the individual modules andhandles:
Overall set-up, control, and external communication
Permanent storage of up to 16 predefined settings (Profiles)
High-level communication interface, including serial RS 232/422, LAN interface, ad-vanced control functions and Front Panel for local control and setting
Remotely accessible BITE (Built-in Test Equipment) and radar parameter set-up func-tions with built-in performance history/error log
6.2 Transmitter
The transmitter generates the high-frequency pulse trains by means of a magnetron. It is controlledfrom a direct drive modulator with programmable pulse width (PW), programmable Pulse RepetitionFrequency (PRF) and programmable stagger. Hence, optimum coverage is ensured. Furthermore, thisallows for suppression of second-time-around echoes and of running rabbits (interference from otherradar stations) by correlation.
During transmission high voltage and high current pulses are applied to the magnetron cathode. Asolid-state switch generates pulses by directly switching an EHT (Extremely High Tension) power sup-ply. For optimal target detection, the pulses are uniform with a well-defined shape. Once steady-stateoperation is achieved, the Modulator Controller currently adjusts the EHT and filament supplies accord-ing to its programmed values. The voltage levels and timing of output pulses and the filament voltageare adapted to each magnetron type.
The built-in micro controller maintains a set of magnetron data defining the operational limits of themagnetron with algorithms controlling the magnetron operation.
6.2.1 Sector Transmission
The SCANTER 2001 Transceiver provides up to 4 user-defined sectors. Each sector is defined as ei-therProhibit SectororTransmit Sector.
6.3 Receiver
The RF output to the antenna is fed via a 4-port circulator, which is a part of the integrated low noisereceiver is illustrated in Figure 6.2. A dummy load of sufficient capacity is fitted to the fourth port to ab-sorb any reflected returns from the antenna. In this way the magnetron is presented with constant loadimpedance ensuring frequency stability.
A solid-state limiter passively protects the receiver circuits during the period of the transmitter pulse andagainst high power emissions from other radar sites. The limiter also acts as a current controlled at-tenuator to provide an RF swept gain facility, i.e. sensitivity time control (STC), for the discrimination ofsea clutter and close range echoes. Due to the fast recovery time of the limiter, radar returns are use-able after 75 ns.
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Antenna Port
Magnetron Limiter
DummyLoad
L.O.
AFC
Low noise
amplifiers
Log IF Video
Figure 6.2: Integrated Low Noise Receiver
The STC characteristics are programmable and remotely controllable. Additionally, the attenuation ofthe limiter can be controlled by a feedback signal from the Static Clutter Map (SCM), providing sup-pression of stationary clutter signals.
Low-noise RF and IF pre-amplifiers and an image-rejection mixer are employed to ensure that the re-ceiver has a low noise figure for maximum sensitivity. A dual-slope logarithmic amplifier technique withfast response and transfer characteristics combines the dynamic capabilities of traditional logarithmic
amplifiers and the fast response of linear amplifiers (See Figure 6.3).
Figure 6.3: Receiver transfer characteristics
The technique has proven to give high quality radar pictures throughout the range of X-band applica-tions. A special cut-off feature combined with IF filters optimised for fast response prevents pulsestretching. This provides the ASC circuits with optimum conditions.
The AFC employs a separate mixer and receives a trigger pulse derived from the transmitted pulse tosample the IF waveform during the transmitter pulse to lock the operating frequency of the receiver tothe transmitted frequency.
6.3.1 Overall description
The receiver is required to provide all desired receiver functionalities for all possible configurations ofthe SCANTER 2001 Transceiver.
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The receiver provides signal outputs for further video processing in the radar system. Control, calcula-tion and BITE are implemented on the receiver controller board. Figure 6.4 shows a block diagram ofthe X-band Receiver with signal connections indicated.
Figure 6.4 Overview of the X-band Receiver functional blocks and electrical interface.Input and output signals are indicated with arrows.
1) From the magnetron the radar pulse travels through a short section of waveguide fromwhere the forward power is sensed. Also, a RF sample of the pulse is collected and fedto the Automatic Frequency Control, AFC, circuitry.
2) The pulse travels through two three port circulators before reaching the antenna port.The two circulators effectively work as one four port circulator. Thus, the transmittedpulse may propagate from the magnetron to the antenna port and the echo (and re-flected pulse due to e.g. possible antenna mismatch) may propagate to the limiter. En-ergy reflected from the limiter is absorbed in a matched load. Hence, the transmitter(magnetron) is isolated from possible reflections. Also, all sensitive parts of receiver areisolated from the transmitter.
MAG-Sample
AFC-Mixer
Circulator(Isolator)
Detected
pulse
Antenna
Port
100 MHz IF (AFC)
Circulator
WG-Slice
Limiter/STCCirculator
LNFE
L
L
Noise
Source
LO-Sample
Magnetron Port
LNA IF-Filter
BankLog-Amp Video-Amp
Forward power
circuit
Noise Figure
Circuit
100 MHz IF (AFC)AFC-Circuit
+5V
-5V
+12V
-12V
V_
Fwp
V_
AFC
BW1-4
Integrate_
Noise
Enable_
Noise
P_
Noise
V_
LO
STC1-2
NS_
Drive
100 MHz
IF
100 MHz IF
Mod-trigger
Pre-Trigger
+5V
-15V
+15V
Com/Control
Ext.STC
Log Video
IF Test Point
Receiver
Controller
IF and baseband
parts
Microwave
parts
224 2
Detected
pulse
Detected
pulse
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3) A limiter stage is inserted to provide passive protection of the sensitive parts of receiverand to provide an active RF swept gain facility. The limiter is constructed as a seriesconnection of a two-stage limiter and an additional single-stage limiter. The attenuationis determined by a current source, which is controlled by the receiver controller.
4) A noise source diode is inserted in the waveguide channel between the limiter and anisolator. The noise source diode generates excess noise in the waveguide channel just
prior to pulse transmission and is used as reference when measuring the receiver NoiseFigure (NF). The noise diode current source is controlled by the receiver controller.
5) An isolator (implemented using a third circulator) stage is located between the noisesource diode and a LNFE to prevent the local oscillator noise of the LNFE to be emittedthrough the antenna and to limit the variation in impedance matching (seen from the in-put of the LNFE) due to various limiter settings.
6) The LNFE consists of a low noise amplifier, a voltage controlled local oscillator and animage rejection mixer. The voltage controlled oscillator frequency is set by a DC voltagecontrolled by the receiver controller.
7) The Intermediate Frequency board follows the LNFE. The IF board contains a low noise
pre-amplifier, a bandpass filter section and a demodulating logarithmic amplifier. Thepre-amplifier provides amplification of the received signal to match the required inputlevel of the demodulating logarithmic amplifier. The bandpass filter section is matchedfor different pulse lengths and thus provides improved signal to noise ratio while pre-serving the pulse shape.
8) The logarithmic amplifier provides logarithmic envelope detection of the received signal.The logarithmic amplifier furthermore acts as a compression type amplifier providing adual slope characteristic. Thus, discrimination of small targets is improved without add-ing pulse stretching to returns from large targets.
The noise figure circuit provides measurement of the receiver noise figure during radar operation. The
receiver controller calculates the NF based on the values of the receiver noise and the reference (ex-cess) noise measured in separate pulse repetition intervals (PRIs).
The transmitted pulse is detected to provide in operation monitoring of the forward power and gener-ates a trigger used by the AFC.
The purpose the Automatic Frequency Control is to lock the RF local oscillator to the centre frequencyof the transmitted radar pulse. The AFC contains a separate microwave mixer, which multiplies the LOsignal with a sample of the magnetron signal. The product is passed through a phase discriminator,which compares the phase of the two signals and produces an AFC error voltage with reference to the100 MHz signal. The error voltage is proportional with the magnetron frequency deviation from itsnominal value and used for control of the LO.
The receiver controller provides all control, timing, communication and measurement functions.
6.4 Motherboard and Power assembly
The motherboard and power assembly comprises:
Timing Circuitry
Safety Functions
Azimuth Interface
Auxiliary Inputs/Outputs
Power Supply
6.4.1 Safety
The Safety functions include two separate current loops as illustrated in Figure 6.5. Both loops must be
kept unbroken to maintain normal function of the radar.
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Door
Switch
uC
Controller
Man Aloft
Switch
Antenna
Motor Enable
Modulator
Enable
Motor
Fault
External
Internal
DC DC
Loop 1 Loop 2
Figure 6.5: Safety loop principle
Loop 1 is an internal loop which, if broken, will inhibit the modulator trigger and remove the high-tensionvoltage from the modulator(s). The Man-aloft Switch, the Motor Fault signal, the on-board controller andthe door switch control Loop 1.
Loop 2 is an external loop, which controls the antenna motor. The Man-aloft Switch and the Motor FaultSignal controls Loop 2.
The micro controller on the motherboard monitors the status of both loops.
No loop resistance is allowed to be more than 100 .
6.4.2 Auxiliary I/O
The Motherboard provides a set of inputs and outputs for monitoring and control of external equipmentsuch as Oil Level, Dehydrator Low Pressure alarm etc.
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SCANTER 2001
Motherboard
Backplane
On board
Controller
DC
DC
DC
DC
Auxiliary Input 1
Auxiliary Input 2
Auxiliary Input 3
Auxiliary Input 4
Auxiliary Output 1
Auxiliary Output 2
Auxiliary Output 3
Auxiliary Output 4
Relay
Relay
Relay
Relay
Figure 6.6: Auxiliary Inputs and Outputs in SCANTER 2001
6.5 Transceiver Controller
The SCANTER 2001 Transceiver Controller is based on a Power PC microprocessor.
The module provides the overall set-up and control, including serial communication and LAN channelfor remote access. A panel with alphanumeric display and input keys gives full access for local serviceand set-up.
A database hosts Profiles setting the operational characteristics for the individual systems and easingset-up and operation.
6.5.1 On-line monitoring
BITE measurements from all modules are monitored and corrective action is taken on error. If parame-ters fall out of specifications, a warning or error message is issued.
This includes memory checks etc. during start-up as well as continuous monitoring of:
Mains-on time and magnetron-on time
Transmitter Power
Noise figure, internal voltages and temperatures of the Receiver
Internal supply voltages
Magnetron high voltage and magnetron peak current
Modulator internal voltages, currents and temperatures
Signal activity on trigger and video signals
Status from motor, gear and auxiliary inputs providing antenna status
The individual BITE measurements can be accessed continuously.
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Overheating at one or more of the temperature test points will issue a warning message and criticaloverheating will result in automatic shut down
In dual systems, the radar will go into fallback mode or automatically switch over in case of error in oneof the Transceivers.
Mains-on time, magnetron-on time, performance parameters and an error log are stored in non-volatilememory for later reference. This provides a tool for determination of magnetron end-of- life criteria and
for other maintenance issues.
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6.6 Radar Signal Distribution
The Radar Signal Distribution contains video, trigger and Azimuth crosspoints as well as signal driversas illustrated in Figure 6.7
RADAR SIGNAL DISTRIBUTION
DIGITAL VIDEO
DIGITAL VIDEO
COMP. VIDEO A
VIDEO ACOMP. VIDEO B
VIDEO B
TRIGGER
CROSSPOINT SWITCH
VIDEO
COMP.VIDEO
LINE
DRIVER
LINE
DRIVER ACP
ARPLINE
DRIVER
LINE
DRIVER ACP
ARPLINE
DRIVER
LINE
DRIVER ACP
ARPLINE
DRIVER
VIDEO
CROSSPOINT SWITCH
VIDEO
DRIVER
VIDEO
DRIVER
VIDEO
DRIVER
CAN
DRIVER
CAN
DRIVER
CAN
ARP
ACP
B-TRIG
PPI-TRIG
EXT.PRE-TRIG
T0-TRIGA
T0-TRIGB
DIGITALVIDEO
CONTROLLER
CAN
Controller
CAN
Controller
Microcontroller
POWER
8 BIT DIGITAL
VIDEO OUT
+5VDC
-5VDC
+15VDC
-15VDC
TRIGGER OUT 1
TRIGGER OUT 2
TRIGGER OUT 3
VIDEO OUT 1
VIDEO OUT 2
VIDEO OUT 3
B-TRIG A
B-TRIG B
+ 5 VDC
- 5 VDC
+15 VDC
- 15 VDC
+ 5 VDC
- 5 VDC
+15 VDC- 15 VDC
EXTERNA
LCONNECTIONS(RSDON
TRANSCEIVER
2)
EXTERNALCONNECTIONS
MOTHERBOARD & POWER ASSEMBLY
VP
3
TRIGGER OUT 4
AZIMUTHCROSSPOINT SWITCH
ACP OUT
ARP OUTACP INARP IN
VIDEO SWITCH
BUS
DRIVER
BUS
DRIVER
BUS
DRIVER8 BIT DIGITAL
VIDEO OUT
8 BIT DIGITAL
VIDEO OUT
LINE
DRIVER
LINE
DRIVER
LINEDRIVER
LINE
DRIVERTRIGGER OUT 5
CAN
DRIVER
TRIGGER /
VIDEO
COMBINER
Figure 6.7: Radar Signal Distribution
In dual systems will in total as many as 6 pairs of outputs be available at any time as the distributionmodules in the two separate channels are powered in redundancy from both units and further receivessignals from both units. This means that even if the mains supply on one channel is switched off, willthis channel still be able to provide valid signals.
6.7 Mains Distribution
All power and status signals to and from the antenna motor are connected through the Mains Distribu-tion module as illustrated for single systems in and for dual systems in
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Figure 6.8.
The enclosure of this module is EMC/RFI protected and all internal connections filtered.
Please refer to the description of add-on features regarding antenna motor control.
SCANTER 2001
Mains Distribution
Motherboard / PowerSupply Assembly
Encoder
Pwr. Supp.Sector /
Azimuth
Switch
Driver
SCANTER 2001
Motherboard / Power Supply Assembly
Backplane
Mains Distribution
TERMA
MainsSwitch
EMIFilter
Man AloftSwitch
3 Phase Mains
Mains
3 phase
Antenna Out
Man Aloft Switch
L1
L2L3
N
Sector /
Azimuth
Encoder
Pwr. Supp.
Switch
DriverOnboard
Controller
Output1
Output2
GND
Circ.
Hor.
Ver.
GND
Encoder 1 WG SwitchPolarisation
Switch
Relay
Status SignalsSafety
Loop
Safety
Loop
Mains
L1
L2L3
N
Safety Loop
Motor FaultMan Aloft Switch
Motor Warning
Low OilGear BoxMotor Fault
5.3VDC
GND
Sense1
Sense2
ARP
ACP
ACP
ARP
Sense2
Sense1
GND
5.3VDC
AntennaMotor
Control
Encoder 2
Figure 6.8: Mains distribution and Antenna interface for Dual Systems
6.8 Antenna interfaceThe antenna interface is mounted partly on the motherboard and partly on the Mains Distribution asillustrated in Figure 6.8.
The motherboard serves as receiver and converter of data from the encoder as well as distributor ofazimuth information inside the radar. Power is supplied to the azimuth encoder.
In diversity systems will each Transceiver supply the power for one encoder.
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6.9 External connections
All external access is provided through the bottom of the SCANTER 2001 Transceiver housing asshown in Figure 6.9.
Motherboard
Radar Signal Distribution
Mains Distribution Unit
Front
Back
Figure 6.9. External connections
7 ADD-ON FUNCTIONS
7.1 Built-in antenna motor control
The mains distribution module contains the motor control in a 3 to 3-phase inverter (frequency con-
verter) as an integral part of one of the cabinets. Thus, the module is fully self-contained, including a 3-position mains power inlet switch. This allows for servicing of the Transceiver without interruption ofantenna functions.
Additionally, motor protection interface is included, based upon a thermal switch integrated in the an-tenna motor.
7.1.1 Programmable speed
Built-in antenna control with programmable speed control and soft start is available in the following con-figurations:
380-440 V, 3-phase input for up to 2.2 kW, 3-phase motors
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Figure 7.1:Crate with Con-troller and Signal Process-ing Modules
VP
ASC/SCM
ASC/SCM
SELECT
EXIT
RESET
Modulato
r
Warming
up
TC3SCD Spare
FAN
ASCor
SCM
ASCor
SCM
7.2 Signal Processing
The Signal processing consists of plug-in modules for the crate:
The video processor (VP) performing analogue to digitalconversion, digital processing and output signals in 3 videoformats
The Static Clutter Map (SCM) has a fine grid for masking ofthe static clutter sources in close range applications(Optional)
The SCM is intended for stationary applications only. The VP iscompulsory.
Systems equipped with SCM modules require on-site programming withmasking of land echoes and other unwanted stationary targets. Thisrequires the Static Map Programming Tool (SMPT).
7.3 Video Processor
The Video Processor performs 8-bit analogue to digital conversion, digital processing and output sig-nals in 3 video formats as illustrated in
Figure 7.2
2 sets of input signals are handled and combined in Frequency Diversity systems.
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80-100 MHz
ADC
FTC
Sliding window
integrator/combiner
80-100 MHz
ADC
FTC
SCMSCM
Retiming FIFO
Protocol
Control
DAC
NoiseCancellation
NoiseCancellation
Output
Control
B-TRIG
T01T02
SYNC
SYNC
ANALOG
VIDEO
COMPOSITE ANALOG
VIDEODIGITAL
VIDEO
LIMITER LIMITER
LOG VIDEO 1 LOG VIDEO 2
Manuel
STCMinimum
STC
attenuation
Manuel
STC Minimum
STC
attenuation
Sweep
memory
Sweep
memory
DAC
AZIMUTH
AND STATUS
Figure 7.2: Video Processor Functional Diagram
The noise cancellation, made by N of M correlation, reduces the white noise in the signal before furtherprocessing.
Digital FTC filter utilising high pass filter/differentiation, remove or reduce scattering from volumes and
extended static areas. Negative parts of the differentiated signal are clipped to zero voltage.
After the FTC, decimation reduces the sample rate to the desired rate for further processing.
In frequency diversity system the Video Processor corrects for the difference in squint between the twofrequencies applied and aligns the sweeps by correcting for the delay between the first and the secondpulse in each pulse repetition interval.
Re-timing may be utilised to stretch the first part of the sweep (echo) in time.
The processed video is made available as 8-bit digital video as well as analogue video.
Two processed analogue video outputs are at hand. One contains a configurable composite signal toimplement different protocols, including trigger, status and azimuth information. The other contains theprocessed radar video signal only.
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7.3.1 Control and Timing
A micro controller with associated hardware performs the on-board control and BITE.
At start-up, the micro controller performs a self-test of the Video Processor module, establishes com-munication with the Transceiver Controller, and supplies initialisation data for the programmable gatearrays etc.
During operation, the micro controller communicates with the Transceiver Controller to enable thechanging of parameters and reporting in case of malfunctions. Fallback modes are automatically se-lected in case of Transceiver failure, maintaining operation with the operative unit, and issuing a de-creased-performance warning for the other unit.
7.4 External Bi-Directional Couplers
To ease external maintenance and measurements of Forward and Reverse Power is a coupler in-cluded with the following microwave characteristics:
Coupling Forward Power: 30 dB
Coupling Reverse Power: 20 dB
Directivity >15 dB
Connections for Test equipment: N-female
The coupler will be provided with a calibration test sheet for exact coupling figures.
The system is further equipped with a wave-guide switch on each channel in the way that the RF-output can be connected into dummy load if required for maintenance purposes. Each RF componentis capable of handling excess powers of substantial level compared to normal operational power loads.
7.5 Dehydrator
The run of the wave-guide in combination with the length requires a dehydrator to feed compressed dryair into the waveguide.
An automatic regeneration of the desiccant membrane dryer is provided from Andrew. The dehydratorprovides a Low Pressure warning output, which can be monitored by the Control and Monitoring Inter-face. Further, on the front of the dehydrator is a pressure meter for easy monitoring of the wave-guidepressure. The pressure is as factory default set to app 5 PSI.
The separated moisture is purged from the membrane into the atmosphere directly. Hence the dehy-drator doesnt require any maintenance.
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8 TECHNICAL SPECIFICATIONS
8.1 Transmitter
8.1.1 Magnetron Power, Frequencies & Pulse Widths
X-bandHigh res.
Modulator High Power
Nominal Pulse width, range 40 ns
Nominal Magnetron PeakPower
25 kW
Peak Power at output flange 17 kW
2dB
Standard TX frequencies[MHz]
9375 30
9410 30Special TX frequencies [MHz] 9170 30
9438 25
9490 30
Other frequencies within the receiver range may be defined in accordance with special customer re-quests. Units for frequency diversity operation are supplied with the transmitter frequencies 9170 and9438 MHz.
8.1.2 PRF
The available PRF ranges versus PRF and IF bandwidths are:
PW PRF IF BW
Very Short Pulse (VSP) 40 ns 800-8000 Hz 50 MHz
The PRF limits may be exceeded when using stagger.
Programming tolerances:
Set-up PRF = 25x104/K; 31K625 without stagger
Max. operational tolerance 1% (in respect to set-up value without stagger)
8.1.3 PRF stagger
Pseudo random stagger is available in programmable modes (selectable as set-up and service set-tings).
0% stagger No staggering
2% stagger From +1.5% to -2% from nominal PRI in 8 steps
4% stagger From +3% to -4% from nominal PRI in 8 steps
8% stagger From +6% to -8% from nominal PRI in 8 steps
8.1.4 Sector transmission
In Sector Transmission, the defined sector is the transmit or prohibit part.
Number of sectors 4
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Sector bearing: 0-359
Sector width: 10-360
Resolution: 1
8.1.5 Pulse Parameters
The output Pulse Width is measured as the half power (See Figure 8.1).
Droop
10% power
90% power
50% (-3 dB) power
Tpulse
Tf
100% power
Tr
Figure 8.1: Magnetron output-pulse
The RF output pulse from the magnetron is programmable within the following limits:
Step size 10 ns
Tolerance 10%, PW 100 nsRise Time (Tr) Nominal 15 ns, High resolutionFall Time (Tf) Nominal 15 ns, High resolutionMax. Droop 1% per 50 ns up to 600 ns
Increasing to max. 50% at 1.000 ns
Frequency Push 1.5 MHz (max. half IF BW)
8.2 Receiver
8.2.1 Frequency Bands
The receiver bands for the product range:
X-band 9.100 - 9.300 GHz9.300 - 9.500 GHz
8.2.2 Dynamic characteristics
The Noise Floor, the STC characteristics and the Log amplifier characteristics determine the dynamiccharacteristics.
Receiver overall dynamic range including STC:
X-band 125 dB
IF amplifier:
Type logarithmic, fast response withspecial characteristics (See Figure 6.3)
Dynamic range 95 dB, combining active and cut off region.
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Limiter RF attenuation (STC/SCM):
X-band 50 dB
Limiter recovery time 200 ns to 6 dB attenuation.
8.2.3 Noise Figure and Image Rejection
The Noise Figure of the S & X band receivers:Typical Limit
LNFE 2.0 dB 2.5 dB
Overall, 0-30C ambient temp. 3.5 dB 4.0 dB
Overall within 30-55C ambient 4.0 dB 4.7 dB
The balance image-rejection mixer suppresses noise located at the image frequency.
Typical LimitImage rejection 22 dB 18 dB
8.2.4 Receiver Noise Floor
The thermal noise at the receiver input and the receiver Noise Figure determines the receiver noisefloor.
[ ] [ ]dBmMHzBWNFFLOORNOISEOV
)(log10114_ 10++=
From this expression, the noise floor can be computed for the various receiver bandwidths.
BW Noise Floor Tangential Meas.
50 MHz 91 dBm -85 dBm
Table 8.1: Receiver noise floor versus bandwidth
The Minimum Detectable Signal, MDS, is determined by the signal processing and thus system de-pendent.
8.2.5 IF Filter
Centre Frequency:
X-band: 100 MHz
Filter stage/
Specs.
BW#1,
Pulse lengths 40ns
3dB Bandwidth 50 MHz
Table 8.2: Bandwidth selections
8.2.6 Power and Noise figure Monitoring
Forward Power monitoring
Measurement range 2-30 kW *)Accuracy +/- 10 %Alarm level (OFF), 2-20 kW
Noise Figure Monitoring
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Measurement range 2-15 dBAccuracy +/- 10 %, however, not better than 0.5 dB *)Alarm level 5 15, (OFF) dB
*) Relative to external calibration standards.
8.3 Antenna Interface
8.3.1 Azimuth Encoder
Antenna rotation rate 6 60 RPM 10 %Pulses per revolution 4096 or 8192 ACPs + 1 ARPPulse widths ACP10 s, ARP 10 sFormat 2 * balanced line, RS-422Encoder Supply + 5 V +/- 5 %, max 500 mA, diode coupled
and short circuit protected
8.3.2 Motor Warnings (overheat protection)
Mechanism Open/closed contacts, 20 mA current loop
Functionality:Normal operation Closed contacts, motor supplies enabledOver-temperature error Open contacts, motor supplies disabled
and error message issued
Coupling With diode to allow for parallel couplingContact rating 30 V DC, 50 mA
8.3.3 Gearbox
High temperature warningMechanism Open/closed contacts, 20 mA current loop
Functionality:Normal operation Closed contacts, no actionHigh temperature Open contacts, warning message issued
Coupling With diode to allow for parallel couplingContact rating Min. 30 V DC, 50 mA
Low oil level warningMechanism Open/closed contacts, 20 mA current loop
Functionality:Normal operation Closed contacts, no actionLow oil level warning Open contacts, warning message issued
Coupling With diode to allow for parallel couplingContact rating 30 V DC, 50 mA
8.3.4 Antenna Polarisation Switch Control Output
Voltage 28 3 VCurrent source capacity Up to 3 A pulse for 1-3 secondsFunctionality +28 V to output 1, for circular+28 V to output 2, for horizontal+28 V to output 3, for verticalPulse supply to change state. Each line with diode in series for parallel coupling.
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8.4 Waveguide Switch Control Output
Voltage 28 2 VCurrent source capacity Up to 3 A pulse for 1-3 secondsFunctionality +28 V to output 1, Transceiver 1
+28 V to output 2, for Transceiver 2Pulse supply to change state.
8.5 External Trigger (Sync) Input
Amplitude 5-15 V positive pulseImpedance 75 ohm nominal loadPulse width 0.1 sConnector type: BNC 75
8.6 Auxiliary I/O
8.6.1 Auxiliary Inputs
Number of inputs 4Format 20 mA current loop for external contactsLevel FloatingContact rating 30 V DC, 50 mA
8.6.2 Auxiliary Outputs
Number of outputs 4Format Relay contactLevel FloatingContact rating 100 V, 1.0 A DC, 50 VA max.
8.7 Data communication
Data communication lines are available for control and remote service as well as for interfaces to otherunits within a system.
No. of serial communication lines 4 (1 shared)Interface level RS-422A / RS-232Protocols Terma 262001 SI
TCP/IPNMEA 0183 (Subset)
No. of CAN communication lines 1 (shared)Type Fault-tolerant driver
Speed 125kbpsInterface standard: ISO-11898Protocols: Terma 262001 SI
Ethernet 10BaseT / 100BaseTX (twisted-pair)Connector type: Cannon DB9P or equivalent
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8.8 Radar Signal Distribution
The Radar Signal Distribution module contains the application specific external connection (e.g. num-ber of video/trigger outputs, type of signals etc.), i.e. different modules may be necessary to differentapplications. The Radar Signal Distribution provides 4 sets of radar signals.
8.8.1 Trigger Output
No of outputs 6, each programmable to supply T0, PPI or pre-trigger,plus B trigger in case of built-in video processing
Amplitude +8 1 VDrive capacity 75 nominal loadPulse width 1.0 sFunctionality Trigger point at low-to-high transitionRise time 180 ns (10-90%)Connector BNC
8.8.2 Analogue Video Output
No of outputs 4 each programmable to supply log or composite video *).Level -1 V to +1 V @ 50 or 75 nominal loador 0 V to +5 V @ 75 nominal loadIndividually selectable for each output
DC level 0.05 / 0.5 V DCConnectors BNC*) Composite video requires the Video Processor to be present.
8.8.3 Digital Video Output *)
Video Amplitude resolution 8 bitsFormat 12 * differential lines 8-bit data + status outputs.
RS-422, max 10 MHz output rateor EIA-644, max 40 MHz output rate
*) Digital video required the Video Processor to be present.
8.8.4 Azimuth Output
The output follows the input of the azimuth encoder, being 4096/8192 clock pulses (dependent oftype), with 12/13 bits resolution of azimuth information (ACP), as a serial string as well as 1 ARP foreach antenna revolution.
No of outputs 4Antenna rotation rate as inputPulses per revolution 4096 or 8192 ACPs + 1 ARPPulse widths ACP 10 s, ARP 10 sFormat 2 * balanced line, RS-422
8.8.5 Mains Power Supply
Voltage 115-242 V AC +8/-10%
Frequency 47-63 Hz
Power Max 350 VA,Max 500 VA, Single Frequency Diversity and Dualredundant Frequency Diversity configurations. (ex-cluding Antenna Motor Power)
Power factor Cos 0,90, transmitting, high power
Cos 0,80, non-transmitting or low power
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9 ADD-ON SPECIFICATIONS
9.1 Built-in Antenna motor control
9.1.1 Programmable motor speed
TypeMotor:
Max nominal power 2.2 kW
Phases 3
Voltage as input
Nominal Frequency 50/60 Hz
Mains Input:Phases 3
Voltage 380 - 480 10%
Max current per phase 6.4 A
Frequency 50/60 Hz
Programmable output frequency 0 - 90 Hz
Motor protection ElectronicMax Power loss 90 W
Larger motors may require external motordrives
.
9.2 Video Processor
9.2.1 A/D Conversion
8-bit80 MHz or 100 MHz selectable
9.2.2 Noise Cancellation
3 out of 4 correlationPulse width discrimination for pulses < 25 ns when using Tx pulses up to 60 nsPulse width discrimination for pulses < 50 ns when using Tx pulses above 60 ns
9.2.3 FTC
The time constant is selectable in the range 0.1 2.0 s.
9.2.4 Sample Rate DecimationThe sampling rate of either 80/100 MHz can be decimated with factors 1, 2, 4,and 8.
9.2.5 Sweep Memory
Memory depth (one sweep) 32 KbytesMemory width (each channel) 256 sweeps
9.2.6 Output rate / Re-timing
Output rates 10, 20, and 40 MHz
Note that the maximum output rate is 40 MHz, meaning that the input sample rate of 80MHz is decimated, or the output shall be re-timed.
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9.2.7 Analogue Video Output
Radar Video Amplitude Res. 8-bitFormat Analogue D/A Converter outputDAC output rate 10, 20 or 40 Ms/s, selectable depending on the re-
timing factor.DC level (signal reference level) 0V
Radar Video polarity Pos. polarityVideo Band width 40 MHzTiming Synchronised with the B_TRIG signal.
9.2.8 Composite Analogue Video Output
Radar Video Amplitude resolution 8-bitFormat Analogue D/A Converter outputDAC output rate 10, 20 or 40 Ms/s, selectable depending on the re-
timing factor.Overall signal range Min.: -1.0V; Max: 1.0V (in 50 load)DC level (signal reference level) Configurable from -1V to 0VRadar Video polarity Configurable to Pos. or Neg. polarity
Video Band width 40 MHzTiming Synchronised with the B_TRIG signal.Protocols Fulfil protocols according to Terma documents:
245692 ED249530 PM254016 DI254017 DI
9.3 Static Clutter Map (Option)
The most important factors in respect to elimination of false targets due to multipath propagation andother factors is the antenna siting. Careful study of the topographical conditions at each individual site,
done by experienced radar system engineers, is required to minimise multipath problems.
The clutter map and blanking functions can be used for attenuation or blanking of false targets in se-lected areas, however, this always will be set as a compromise between sensitivity to see desirabletargets and elimination of false echoes.
Multipath returns also can originate from moving objects.
The Static Clutter Map provides two-dimensional (range and azimuth) swept gain on RF as well asblanking (on video level) of unwanted stationary targets.
Stationary unwanted signals can also be removed by display processing on baseband signals but theadvantage of this module is obvious as it works up-front the receiver and hence prevents possible satu-ration from large targets that will reduce resolution and detection in the vicinity of these.
The two-dimensional swept gain map and the blanking map is defined by means of the Static Map Pro-gramming Tool (SMPT) running on the Service Display. For that purpose, a radar site map of the air-port is needed. The maps are defined on top of the radar site maps and converted to a format appro-priate for the Static Clutter Map assembly.
The two-dimensional swept gain map and the blanking map are transferred to the Static Clutter Mapassembly via a special cable and connectors on the Service Display and the RxTx unit.
9.3.1 Map Characteristics
Instrumented Range 6000 m
Attenuation Map
Number of cells 32 k
Cell size Range 23,976 m
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Cell size Azimuth 2.813
NV store capacity 1 map in NV-RAM
Resolution 8 bit, 0 to 45 dB of attenuationrange spread out on 256 steps
DP-RAM update rate one full update: 1 sec (max)
Blanking Map
Number of cells 512 k
Cell size Range 5.994 m
Cell size Azimuth 0.703
NV storage capacity 2 maps in NV-RAM
Max PRF 8064 Hz
Max RPM 60 rpm
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10 ANTENNA SYSTEM (OPTION)
The SCANTER Radar Systems are tailored for professional customers such as defence, customs,coast guards, airports, and other authorities requiring reliable operation and high performance.
Circular polarisation and beam forming techniques provide low susceptibility to precipitation.
Additional performance is achieved when combined with Frequency Diversity, reducing target fluctua-tion and utilising squint characteristics to suppress clutter.
As the shape of individual water drops approaches perfect spheres, the back-scatter from the circularlypolarised incident electromagnetic field rotates with opposite polarisation. This fundamental character-istic is utilised for suppression of rain clutter and back-scatter from sea spray.
Colour, motor voltages and azimuth interfaces are configurable to meet individual project requirements.
10.1 Product Characteristics
The high gain antenna consist of 2 main assemblies; the Scanner (rotodome) including RF feed andthe turntable. The turntable includes azimuth encoder(s), supports a rotary joint and features mountingof heater elements and sensors.
10.2 The Scanner
The Scanner consists of horn, slotted waveguide, polarisation filter and RF feed housed in a lightweightradome with low-loss impact resistant window protecting against sun radiation.
The parts are fixed in a strong, stiff and lightening protected aluminium structure.
Additionally, circularly polarised units include a multi-layer periodic array polarizer in front of the horn.This provides efficient cancellation of back-scatter from precipitation over the entire frequency rangeand at all elevation angles.
10.3 Turntable & RF Feed
The turntable housing is aluminium cast and contains the drive shaft for the aerial and the turningmechanism. The assembly is fitted with digital transmitter(s) giving output data equivalent to the radia-tion bearing with a 1:1 gearing ratio.
AzimuthEncoder (s)
Figure 10.1: Principal sketch. The number of shaft encoders may vary.
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The azimuth data transfer gear includes backlash on the gearwheels to absorb tolerances and wearensuring maintenance free operation for several years.
Alignment to the north must be performed externally to the antenna, e.g. by the Radar Transceiver.
The drive motor is 3-phased and fixed to the turntable housing with 4 bolts for easy replacement.
10.4 Heater and Sensors
The motor is protected by means of a thermal switch, integrated in the motor stator windings for effi-cient shut down in case of overheat, e.g. as a result of the Scanner being blocked.
60-RPM versions are equipped with sensors for low oil level and high motor temperature
The turntable enables mounting of thermostatically controlled De-icing heaters (optional) for areas withsevere ice conditions. This enables break-up of up to 40 mm clear ice for 20-RPM versions and 20 mmclear ice for 60-RPM versions.
11 SPECIFICATIONS
11.1 Main data
TERMA HIGH GAIN SWG ANTENNA
Antenna Type SCANTER 21' CP-F-38 21' CP-I-37 Unit
MAIN PARAMETERS
Frequency Band 9140 9470 9140 9470 MHz
VSWR 1.15 1.15
Gain 38 37 dBi
Integrated Cancellation Ratio 15 15 dBAZIMUTH PATTERN
Horizontal BW @ - 3 dB 0.35 0.36 deg
Side lobe level from +/-1.5o to +/- 5o
-28 -28 dB
Side lobe level from +/-5o to +/- 10o
-30 -30 dB
Side lobe level outside +/- 10o -35 -35 dB
ELEVATION PATTERN
Elevation Beamform Fan Inv. csc2
Inv. csc2
law to -36 deg
Vertical BW @ - 3 dB 11 11 deg
Coverage to min., @ -30dB -18 -40 deg
Tilt (Fixed) -1.5 -0.6 deg
TURNTABLE
Motor 2.2 kW, 3-phase
Scanner rotation speed @ 50 Hz60 RPM
Built-in sensors, standardAdd-ons
Motor protectionMotor, high temp. warning / Low oil level warning
Azimuth encoder, standard 2 * 4096 pulses
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11.2 Horizontal Radiation Pattern
The 3dB point is often used as the main key parameter in antenna specifications. However, in prac-tice achieving good overall shape and low far side lobe levels is equally important.
Requirements to all intended applications are virtually identical. Thus, the horizontal radiation (Azimuth)pattern is shaped as measured in Figure 11.1.
Figure 11.1: Measured Horizontal Radiation (Azimuth) pattern and specification limits
21' CP-F Antenna - Azimuth Pattern
-40
-35
-30
-25
-20
-15
-10
-5
0
-15 -10 -5 0 5 10 15Azimuth Angle [deg]
[
dB]
Azimuth beamwidth: 0.32 deg
Measured value 0.35 deg Compensation for near field -0.03 deg
Serial no.: 3018
Date: 2. November 2000
Frequency: 9.375 GHz
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11.3 Elevation Patterns
The Inv. csc2
Beam antennas elevation patterns are optimised for maximum gain and without signifi-
cant nulls for coverage to - 40 as illustrated in Measured elevation pattern
21' CP- I Antenna - Elevation Angle
-60
-50
-40
-30
-20
-10
0
10
20
-40 -30 -20 -10 0
dB
Elevation
angle[deg]
Elevation beamwidth: 9.1 deg
Serial no.: 3002Date: 19. June 2001
Frequency: 9.170 GHz
Figure 11.2 Measured elevation pattern, Inverted CSC2
11.4 RF Power handling
The antenna handles the following RF power levels:
Peak: 100 kW
Average: 75 W
11.5 RF Flange
PBR 100, plain flange with O-ring sealing and M4 threads, according to IEC154.
11.6 Colour Scheme
Standard: RAL 9010 Pure White
Alternative: RAL 2009 Air Traffic Orange, mainly for SMR applications
12 WEIGHT & MECHANICAL DIMENSIONS
Weight:
Scanner: Approx. 175 kg incl. adaptation to gearbox
Gearbox: Approx. 180 kg incl. oil.
Total unit 375 kg
21 CP-I antenna:
H x L x W: 1060 mm x 6560 mm x 640 mm for the complete unit
Swing radius: 3300 mm
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Figure 12.1: Mechanical outline
Please refer to the Terma installation drawing 250960 ZD for further details.
12.1 Forces acting on the antenna
The antenna shall operate at wind speeds specified in Environmental Capabilities and Constraints,paragraph 12.2. The wind resistance will introduce torques as shown in the table Figure 12.1 Forcesacting on the antenna.
21 Antennas
Torque
ConditionHorizontal Torque
[Nm]Frequency
[Hz]Wind Speed [m/s]
Start Torque 850
Max Torque 775
Cyclic Torque (60RPM) (0) 550 2 35
Lateral Force [N]
Condition Lateral Force [N]Frequency
[Hz]Wind Speed [m/s]
Cyclic 60 RPM 650 1100 2 35
Cyclic 20 RPM 1100 1700 0.66 45
Non operating 2500 55
Figure 12.1 Forces acting on the antenna
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12.2 Environmental Capabilities and Constraints
The antenna family is designed for use in any climate including salt and dust-laden atmosphere, and towithstand the following conditions:
Test Condition Limit Corresponding Stan-dard
Cold StorageFunction
-40C-40C
IEC 68-2-1, test AdIEC 945
Dry Heat StorageFunction
+70C+55C
IEC 68-2-2, test BdIEC 945
Protection Function IP54 IEC Publication 529
Bump Packed for transp.Peak accelerationNo of bumps
10g, 16 ms1000
IEC 68-2-29 test Eb
Shock Non-operating 15g, 11 ms, halfsine
IEC 68-2-27 test Ea
Vibration FunctionNon-operating
4-12.5 Hz: 1.0mm12.5-50 Hz: 0.7 g
IEC 68-2-6 test Fc
Sun radiation Function 1120 W/m IEC 68-2-9 test procedureA
Wind speed Function
Non-operating
35 m/s (60RPM) 55 m/s (20RPM) 75 m/s (sur-vival)
Ice Start up rotating,without structural
damage
20 mm,20 RPMgearbox
10 mm, 60 RPMgearbox
Rain/sea spray Non-operating 1600 mm/h DEF STAN 07-55, test D3
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13 FUNCTIONAL CAPABILITIES
Performance calculations have been performed by analysis using the Computer-Aided Radar Perform-ance Evaluation Tool (CARPET) from TNO Physics, The Netherlands. Parameters values are set tohandle the very short pulses and taking bounce effects into account by enlarging the rain cells to give
an additional 6 dB rain return compared to a no-bounce situation (giving 9 dB cancellation ratio).Calculated performance in rain is significantly affected by the rain cancellation achievable by circularpolarisation and especially the amount of single and double bounce energy received via indirect paths.However, practical experience is that rain or snow hardly affects the Terma radar sensor systems withcircular polarised antennas.
A reflection coefficient of 1 (e.g., from a paved wet surface) will completely eliminate the benefit fromcircular polarisation due to single bounce. Practical experience has however shown this not to be thecase due to the fact that airport surfaces consist of a combination of pavements, vegetation, and largerstructures, where (especially wet) vegetation will absorb energy, reducing the bouncing effect. It is real-istic to assume the rain cancellation of a circular polarised antenna to be reduced from a measuredvalue of 15 dB to the practical value of 8 to 10 dB used in Termas calculation.
The lobing effect is another parameter that is highly dependent on surface characteristics and also is
influenced by the surface reflectivity.
The calculations are made with 4 pulse non-coherent integration of radar returns and Swerling casesas the requirements are calling for.
13.1 Target Detection
The combination of a X-band radar-sensor system together with a Circular Polarised antenna optimisesfor weather penetration. Susceptibility to precipitation is substantially improved in comparison to use oflinear polarised antennas. The following pictures illustrate the performance in heavy rain using the pro-posed 21-foot CP antenna and an 18-foot linear polarised antenna for comparison. The pictures aremade within 2 min with identical processing involved.
Figure 13.1 Linear Polarised Antenna
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Figure 13.2 Circular Polarised Antenna
Detection of real targets such as B737s will normally be presented as a round-like spot, andA340/B747s will be presented with a shape similar to an aircraft.
Figure 13.3 shows a Boeing 747 on taxi approximately 500 meters from the radar position as presentedon the service display (VGA resolution).
Figure 13.3 Terma X-Band System
Aircraft and other mobile targets on an airport occupy 40 dB of the dynamic range at most, after sweptgain on IF. The IF amplifier characteristics are therefore optimised in this region providing the bestpossible working conditions for Frequency Diversity processing.
Other structures on an airport may result in very strong returns, and the overall system has thereforebeen designed to accept input power levels from targets up to 10 dBm without collapsing or significantpulse stretch as a result.
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13.2 Coverage
The coverage is determined by a combination of antenna characteristics, antenna height and localconditions. The results of the following performance calculations yields:
Coverage, Max range [m] Comment
Scenario #1>80 4200
With 4-pulse non-coherent inte-gration processing applied.
Scenario #2 >80 3500 No processing applied
Scenario #3 >80 5200 Frequency Diversity
Table 13.1 Coverage Performance
The short range coverage is purely calculated using the antenna height and the Terma CP-I antennadirectivity at 20dB from the peak in elevation assuming an antenna height of max 32m.
The effective maximum range may, however, be reduced as a result of a high PRF combined with re-timing (PRF at 8000 Hz and re-time factor 4 will result in a maximum range of app. 4500m.)
The Terma radar system with the proposed (optional) antenna provides a 90 percent or greater prob-ability of detection in 16mm/hour of rain, with a false alarm rate of less than 10
-6,for ranges out to
4200m and altitudes up to >100m.
The coverage figures stated herein are based on target locations in clutter free areas i.e. a S/N ratiolarger than app 14-22dB is required to detect the target with a probability of detection larger than 90%.This means that reliable detection above cluttered areas will not be possible. The coverage stated isvalid for 360 degrees.
A high gain antenna i.e. in excess of 39dBi (parabolic) will increase the long range detection capabilityof the system in the order of 1,4-1,5.
The radar sensor system has an unlimited capability of detecting multiple targets within the resolutioncapabilities as stated for the system.
13.2.1 Performance Calculations
The following constraints are used for the radar performance calculations:
The following generic constraints applies to the coverage figures:
Target size: 3m2
Antenna Height (mounted on the tower): 32m (assumed)
Circular Polarised Antenna with 0,6o
fixed tilt.
Gain Antenna: >35 dBi
Pd: 90%Pfa: 10
-6
Processing 4 Pulse Sliding Window Integration
Noise Figure 4,7dB
A system loss that includes 35 Wave-guide between equipment room where the RxTx units is to belocated and the antenna is included in the calculations. This yields in total 3,7dB of loss in the transmit-ter and 4.2dB loss for the receiver.
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By nature are targets fluctuating which naturally tends to decrease the detection performance as a re-sult. However, clutter from grass/ground etc. will be uncorrelated and the detection can hence be im-proved by processing such as Sliding Window Integration and Frequency Diversity processing.
Normally the required S/N ration to detect a target with 90% detection probability is app 22dB, whichcan be reduced 5-6dB by adding sliding window integration. As detection of the real target will be corre-lated in the contrary to the clutter will this improve the detection substantially.
Additional 4-5dB of reduction of the S/N can be achieved by adding frequency diversity processing.This is mainly due to the fact, that the targets will be illuminated with two different frequencies, whichtends to reduce the fluctuations. The