SMR Technical Description

8/8/2019 SMR Technical Description

1/55

Terma A/S, DK-8520 Lystrup, Denmark060307 9:10 SMR Technical description

Technical Description

Airport

Surface Movement Radar System


2/55

Page 2 of 55

Terma A/S, DK-8520 Lystrup, Denmark

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


3/55

Page 3 of 55


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


4/55

Page 4 of 55


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


5/55

Page 5 of 55


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


6/55

Page 6 of 55


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.


7/55

Page 7 of 55


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.


8/55

Page 8 of 55


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.


9/55

Page 9 of 55


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.


10/55

Page 10 of 55


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.


11/55

Page 11 of 55


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).


12/55

Page 12 of 55


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


13/55

Page 13 of 55


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)


14/55

Page 14 of 55


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.


15/55

Page 15 of 55


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.


16/55

Page 16 of 55


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


17/55

Page 17 of 55


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.


18/55

Page 18 of 55


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.


19/55

Page 19 of 55


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.


20/55

Page 20 of 55


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.


21/55

Page 21 of 55


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


22/55

Page 22 of 55


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.


23/55

Page 23 of 55


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


24/55

Page 24 of 55


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.


25/55

Page 25 of 55


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.


26/55

Page 26 of 55


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.


27/55

Page 27 of 55


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


28/55

Page 28 of 55


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.


29/55

Page 29 of 55


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


30/55

Page 30 of 55


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.


31/55

Page 31 of 55


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


32/55

Page 32 of 55


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


33/55

Page 33 of 55


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.


34/55

Page 34 of 55


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


35/55

Page 35 of 55


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


36/55

Page 36 of 55


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.


37/55

Page 37 of 55


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


38/55

Page 38 of 55


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


39/55

Page 39 of 55


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


40/55

Page 40 of 55


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


41/55

Page 41 of 55


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


42/55

Page 42 of 55


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


43/55

Page 43 of 55


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.


44/55

Page 44 of 55


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.


45/55

Page 45 of 55


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

Documents

SMR Technical Description