9.1m Product Description

8/11/2019 9.1m Product Description

1/16

atlanta beijing london new delhi san diego santiago sydney

Product Description

9.1-Meter Remote SensingGround Station

ViaSatSatellite Ground Systems

8 October 2001


2/16

9.1-Meter Remote Sensing Ground Station

Product Description 2

www.viasat.com 4356 Communications Drive, Norcross, GA 30093 USA Tel: +1 678.924.2631 Fax: +1 770.935.3285

History and Experience

Since the inception of the Landsat program in the early 1970s,ViaSat has been the leader in providing Remote SensingGround Station antenna systems. This success began in 1973with the first ground station used specifically for Landsat 1,2and 3, which was supplied to Brazil.

In 1978, NASA awarded ViaSat the first contract to supplyan S- and X-Band Landsat 4 and 5-ground station. At thattime ViaSat developed the high data rate (15/85 Mbps)demodulators and bit synchronizers used for satellite testingand data reception.

In 1984, on-going development resulted in the worlds firstMulti-Function Digital Receive System (MFDRS), which wasinstalled as part of a 10 meter S- and X-Band system atopan 8-story building in Fairbanks, Alaska. This systemenabled reception of data from multiple satellites with themaximum use of common hardware and has since beenused in all ViaSat ground stations.

By 1989, ViaSats expertise in servo mechanism and controlsystems design heralded the first system in the world toacquire and track Remote Sensing Satellite signals at X-Band, in the 10 meter CLIRSEN system in Ecuador.

Further developments in high data rate modem design

resulted in ViaSat being selected, in 1993, by E-Systems &Space Imaging for the provision of their IKONOS groundstations. All have the capability to receive data up to 320Mbps.

Also in 1993, ViaSat delivered the first ever Landsat 7AQPSK demodulator and bit synchronizer to the EROS DataCenter.

As a result of ViaSats success in the delivery of all ofMotorolas 57 IRIDIUM Ka-Band Gateway and TT&Cterminals, a derivative of that systems X/Y pedestal designwas fielded in 1996 for the first time in a mobile remotesensing ground station to support the IKONOS program.

In 1999, a new generation of MFDRS was delivered that wasable to provide data reception from multiple remote sensingsatellites in the 20-320 Mbps range.

In 2000, ViaSat was awarded a contract to provide the first5.4m Ka-Band Remote Sensing Ground Station in support ofNASAs Ka-Band RSGS experiments.

ViaSats Experience

ViaSat has over 30 yearsexperience in designing,

building and installingfull motion, high

performance RemoteSensing Antenna

Systems, and continuesto lead the way in

innovation and productdevelopment


3/16


3 Product Description


ViaSat Remote Sensing Ground Stations World Wide Deployment

Test and Integration

140 Acre Antenna Test and Integration Range High Volume Antenna & Pedestal Production Facility Antenna Testing on Pattern Range System Testing on Boresite Range

Complete Stations

Major Subsystems

World WideExperience

ViaSat has provided

more than 60 RemoteSensing Ground Stationsthroughout the world, in

all locations ranging fromthe tropics to the Arctic

and Antarctic

ViaSat has providedmore Remote Sensing

Ground Stations than allother suppliers

Design, Manufactureand Test

ViaSat designs,manufactures and tests

all of the majorcomponents and

subsystems withinViaSat. Other companies

sub-contract largeportions of the system to

outside vendors

ViaSat has a world-class140-acre test andintegration facility where

the systems are fullytested prior to shipment.

No other supplier hasthis capability

Company Reputation

ViaSat has built itsreputation by supplying

quality products andservices at competitive

prices, and by providingsuperior customer

service before, duringand after contract award


4/16




System Overview

The ViaSat 9.1-meter systememploys many elements oftechnology fielded and proven inremote sensing ground terminalenvironments to provide anapproach that is easy to installand provides state-of-the-artperformance.

The ViaSat 9.1 meter RemoteSensing Ground Station (RSGS),consists of several subsystems.

The following paragraphsprovide a brief overview of thesystem.

Antenna SubsystemThe antenna consists of a ViaSat 9.1-meter dual shapedreflector and Cassegrain feed. The antenna subsystem has beendesigned to easily accept an upgrade of an S-band prime focusfeed and dichroic subreflector in the future. The Cassegrainfeed produces both tracking and data outputs.

The high efficiency dual shaped reflector coupled with state-of-the-art GaAs FET low-noise amplifiers provide a G/T of betterthan 35 dB/K at 5 degrees elevation. This performance willpermit operation with any of the current and planned remotesensing satellites.

Pedestal SubsystemThe antenna is installed on a Model 3316A Pedestal featuringdual, torque-biased, servo drives as well as an east-west tiltaxis. This configuration provides full hemispherical coverage forremote sensing satellite tracking. The pedestal system ismounted on a 4.6-meter base extension that provides adequateground clearance for safety of personnel and equipment.

X-Band Receive SubsystemThe heart of the X-Band receive system is the ViaSatMultifunction Digital Receive System (MFDRS). This system ofdown converters, receivers, bit synchronizers and optional testequipment are designed to provide optimum system bit errorrate (BER) performance under all conditions. The MFDRSproduct has been field proven with more than 25 remotesensing satellites.

Key System Features

ViaSats advanced9.1-meter stretchformed aluminumreflector.

Sufficient link marginto support all currentand planned remotesensing satellites.

ViaSats Model 3316Ahas a long history ofproviding reliableperformance overmany years ofoperation.

Tilt Axis permitsdirect overheadtracking of polarsatellites without lossof data.

ViaSats MultifunctionDigital ReceiveSystem (MFDRS)equipment. Thissystem useshardware field provenwith more than 25satellites.

ViaSats 9.1-metersystem provides a

technically superiorapproach for remote

sensing missions


5/16




Dry Air

Data8.0 - 8.5 GHz

Test8.0 - 8.5 GHz

Track8.0 - 8.5 GHz

CONV ASSY924-4

SERVO CONTROLEQUIPMENT

DC POWERSUPPLIES

PWM SERVO AMPS

AC POWERCONTROL

CONTROL ROOMBASE EXTENSIONEQUIPMENT

AUTOTRACK

SIGNALDISTRIBUTION

DEHYDRATOR

CASSEGRAINX-BAND

RECEIVEONLY FEED

(RHCP)

REFLECTOR

SPARS ANDSOLID

SUBREFLECTOR

3 AXISPEDESTAL

(EL/AZ/TILT)3316

BASEEXTENSION

PWR&

CTRL

PWR/CTRL

PWRIF DIST UNIT

924-7B

EQ

EQ

EQ

EQ

EQ

720 MHz

TEST U/C

TRACK D/C

DATA D/C

DATA D/C

720 MHz

720 MHz

720 MHz

POWERDISTRIBUTION

FREQUENCYSYNTHESIZER



CABLERUN(50m)

WB AM DEMOD924-9B

ANTENNACONTROL UNIT

OUTDOOR

AC POWER

COLORMONITOR

KEYBOARD& MOUSE

STATION CONTROLLER

DISK DRIVE

CDROM

COMPUTER

OPERATINGSYSTEM

APPLICATIONSOFTWARE

TESTMODULATOR

924-6B

DATA

CLOCK

1

WIDEBANDBERT

1

GPS

ExtComputer

PROTOCOL ADAPTER

ETHERNETHUB

NETWORKTIMESERVER

PROTOCOL ADAPTER

POWERMETER

2

PART OFPOWER METER

OPTION2

PART OFBER TEST

OPTION1

PART OF 2ndRECEIVE CHAIN

OPTION3

3

1

I

M&C

I CH DATA & CK

COMB DATA & CK

Q CH DATA & CK

QDEMOD924-1B

BSSC CHASSIS 924-2

S P O T 1

, 2 , 4

S P A R E

S P A R E

S P A R E

S P A R E

S P A R E

33

I

M&C

I CH DATA & CK

COMB DATA & CK

Q CH DATA & CKQDEMOD

924-1B

BSSC CHASSIS 924-2

S P O T 1

, 2 , 4

S P A R E

S P A R E

S P A R E

S P A R E

S P A R E

ANTENNACONTROL UNIT

INDOOR

3

Control SubsystemViaSats Series 3860 Antenna Control Unit (ACU) is a state-of-the-art system that implements digital control servo algorithmswith advanced state model dynamic equalization algorithms toprovide unparalleled system pointing and tracking accuracy.

The drive systems employ high efficiency brushless DC servodrive motors, solid-state drive amplifiers, and high efficiencygearing in an antibacklash torque-biased configuration toprovide reliable performance for years of trouble free operation.

Station Control SoftwareViaSats ground stations offer the most advanced and mostwidely tested computer control and monitoring system availablefor automated remote sensing applications.

This multi-platform capable package has been continuallyimproved since its inception nearly a decade ago. The softwareprovides extensive system automation including hands offsatellite pass operation, fully automated system testing, andremote control from other computer systems. ViaSat will gladlycustomize the software to meet specific customer needs.

Key System Features

Full digital controlover a dual drivetorque-biased servosystem

Highly reliable DCservo drive systeminto a high efficiencygearing system

Fully automatedsoftware controlsystem thatminimizes humanerror during mission

critical operationsViaSats 9.1-meter

system is fullyautomated and

designed forunattended operation


6/16




Antenna Subsystem

ViaSat's High Efficiency Dual Reflector X-band Remote SensingAntenna offers a field-proven system that provides excellentG/T across the 8000 to 8500 MHz band. The geometry allowsfor the independent optimization of the X-band Cassegrainantenna performance and the expansion and independentoptimization of the prime focus S-band antenna.

ReflectorThe reflector design is a dual shaped surface, derived usingproven aperture distributions and surface shaping techniquesthat ViaSat has successfully applied to reflectors ranging from 3meters to 18 meters in diameter.

The all-aluminum reflector consists of a 1.83-meter-diameteraluminum hub, 24 aluminum trusses and 48 aluminuminner/outer panels. The heart of the reflector is the all-aluminum central hub that provides the necessary interfaces

with the pedestal system and the X-band feed. The interior ofthe hub is spacious and provides ample room for systemcomponent mounting. The panels are manufactured at ViaSatusing high-precision stretch-form tooling and assemblytechniques.

The main features ofViaSats antenna

Highest performingG/T in its class

Precision, highquality, shaped mainreflector andsubreflector

High EfficiencyX-Band Feed

Operates acrossentire band withoutthe need for phaseadjustments

Lightning rods andaircraft warning lightsare provided on theupper edge of thereflector and the endof the spars

The utilization ofexisting standard

designs allows ViaSatto propose a cost-

effective design thatwill support all knownand currently planned

Remote SensingSatellites


7/16




Subreflector and Spar AssemblyThe subreflector assembly consists of a shaped solidsubreflector and mount, optimized for high efficiency andantenna performance. The subreflector is supported by foursturdy aluminum spars of rectangular cross section, and isattached to the spars by means of the subreflector mount. Thesubreflector focusing and alignment procedure is performedonce at the factory. The subreflector is then secured and dowelpinned in position to preclude the need for future adjustment.

X-Band FeedViaSats X-band Cassegrain feed operates across the 8000 to8500 MHz frequency band and is designed to maximize G/Tacross the band. All feed components are housed in apressurized and heated feed enclosure that prevents moistureingress and ice adhesion.

The autotracking feed is a 5 horn array with ViaSatsMONOSCAN 1 single channel monopulse tracking technique.This tracking method achieves performance superior to systemsthat employ higher-order mode tracking schemes since thecorrect operation of higher order tracking schemes is highlydependent on the incoming signal polarization.

The 5-horn design provides separate data and tracking outputchannels. The data channels are provided free of the AMtracking error modulation, improving system performance

1 MONOSCAN is a registered trademark of ViaSat, Inc.

Key Feed Features

Cassegrain feedconfiguration

High efficiency, lowloss corrugated horn

RHC polarizationnetwork

Sloped septumpolarizer for superioraxial ratiopolarizationperformance

State-of-the-artuncooled low-noiseamplifiers providegreater than 55 dBgain and 50K noisetemperature

Test injection couplerprior to the LNA


8/16




Pedestal Subsystem

The system employs a three-axispedestal consisting of Model 3316Aelevation-over-azimuth pedestal ontop of an east-west tilt axis. Thisconfiguration provides full coverage ofremote sensing satellites with nokeyhole. ViaSats Model 3316APedestal is a robust configuration thatis uniquely suitable for a remotesensing ground station. It featuresdual, torque-biased servo-drives inthe azimuth and elevation axes. In

the elevation axis both turntables aredriven, rather than just one, to keepthe reflector hub from having todistribute the elevation torquebetween turntables.

Model 3316A Elevation over Azimuth PedestalThe Model 3316A was created for the purpose of handling 10-and 11-meter parabolic reflector antenna systems under highwind conditions and other adverse environments without theneed for a radome. The Model 3316A features include highaccuracy, reliability, safety, and convenience, with a completeline of solid-state control systems and accessories. All portionsof the Model 3316A Servo-driven Pedestal system are ofexisting field-proven design and are in continuing production atViaSat.

The basic pedestal design provides a completely weatherproofunit with extremely high rigidity. All rotating components aresealed to keep out blowing sand, dust and water. Heavy-sectionsteel weldments serve as basic structural members and also asthe weatherproof exterior. Internal components can be reachedthrough access doors or easily removable access covers, andthe pedestal is self-draining to prevent accumulation ofcondensed moisture. Finishes are carefully applied to preventcorrosion due to adverse environments such as salt air. Allelectronic equipment and/or enclosures are configured toprevent the entry of water.

Two dc continuous-duty bi-directional servomotors are used inthe azimuth and elevation axes. The drive motors are built toViaSats specifications with special consideration given tosmooth low-speed operation, high-temperature operation, and

Key Features

Azimuth andelevation have dualdrives for high torqueand zero backlash

Elevation stows havestrength for highwind conditions

Tilt axis permits

overhead orbits to betracked without lossof data

Brushless DCservomotors linked toturntables by highefficiency spur gears

Fail safe brakes andhand drives are used

Turntables withcenter holes for cable

and waveguidepassage

Integrated, Dualresolver and limitswitch assemblies

Resolvers are gearedat a 1:1 ratio and64:1 ratio to theturntable through aprecision anti-backlash geartrain.

4.6m environmentallycontrolled baseextension elevatesthe pedestal andhouses systemequipment


9/16




bi-directional control, limited maintenance and long life. Thesemotors are torque biased to remove any backlash in thesystem.

The azimuth and elevation axes feature travel limit interlocks,stow locks, fail-safe electromechanical brakes, with manual

brake releases, torque limiters, and hand drives for manualpedestal operation. A pedestal disable switch is located at thepedestal base to allow complete power removal from thepedestal drives.

A cable wrap is used to support the travel extremes of thepedestal. The cable, for both RF and control signals, is selectedfor flexibility and life under extreme operating conditions.

Tilt MechanismThe pedestal tilt mechanism serves to tilt the vertical referenceaxis of the tracking pedestal by an amount sufficient to avoidloss of signal from a satellite due to the zenith gimbalsingularity that occurs during an overhead or near-overheadpass.

The tilt mechanism assembly is constructed of two rigid steelweldments, designated the upper and lower tilt mechanismsections. This lower section mounts to the foundation or atop abase extension. The upper section provides mounting for thepedestal and tilts with the pedestal. The upper and lowersections are connected by a set of two pillow-block bearingsand a set of two jackscrew actuators.

A 3-phase AC reversible motor through a worm gear reducersimultaneously drives the actuators. Synchro and limitpackages are provided for position feed back and limitdetection.

Base ExtensionThe base extension elevates the pedestal to the proper heightto provide adequate ground clearance for the antenna reflector.The base extension is a rigid steel weldment providing a stiffoperating base for the pedestal. The base extension has aflange with 12 bolt holes for rigidly mating the base extensionto studs located in the customer-supplied foundation.

The base extension provides an environmentally controlledspace for system-related electronic equipment. The base

extension houses the power amplifiers, DC power supplies,antenna control unit, frequency synthesizers, dehydrator,power and signal distribution units. There is a sufficient well-litworking space within the base extension for basic maintenanceand troubleshooting. There are access ladders both inside andoutside the base extension that provide access to the pedestal,tilt mechanism and antenna hub area.

Pressurization

The feed and electronicsenclosures are suppliedwith dry pressurized airfrom a pressurizationsystem consisting of adehydrator unit andassociated dry airdistribution piping.

The dehydrator unitintakes and dehumidifiesair by means ofregenerative desiccanttowers. The distributionsystem supplies this dry,pressurized air to allcomponents requiringpressurization.


10/16




Multifunction Digital Receive System

For two decades, the great majority of remote sensing groundstations deployed throughout the world have employed ViaSat'sSeries 924 Multifunction Digital Receive System (MFDRS).During this period of time we have continued to refine theMFDRS equipment and to add the capability to receive datafrom each new family of remote sensing satellites as it isintroduced. The versatility and modularity of this system areexemplified in the fact that more remote sensing satellites arecurrently supported with Series 924 equipment than with anyother suppliers systems. The reasons for the high level ofacceptance of this system are:

The architecture of the MFDRS provides high reliabilityand state-of-the-art performance.

The modular design permits ground stations to supportmultiple families of remote sensing satellites with aminimum amount of equipment.

As a result of the superior nature of this system, severalsatellite designers have asked ViaSat to provide the inauguralreceive system for their remote sensing satellites. Recentexamples of this liaison are Radarsat, Landsat-7, IKONOS andOrbview. This close relationship between ViaSat and thedesigners/operators of remote sensing satellites has resulted inthe incorporation of numerous subtleties in the design of the

Series 924 equipment that is available nowhere else.

Model 924-4 ConverterThe X-Band signals are routed from the feed to the Model924-4 converter. This unit, an integral part of the MFDRSproduct line, translates the X-Band signals to an IF of 720 MHz.

The converter unit is a waterproof pressurized chassis. Thechassis is typically located in the hub or on the pedestal riser.By down converting the signals to a lower frequency near thefeed, losses due to RF range cable runs are held to a minimum.Each chassis can house up to five individual converter modules.

The X-band up and down converter modules are members ofthe Model 924-4 family. Each converter module can have aseparate phase-locked source that can be tuned independentlyfrom a commercial off the shelf frequency synthesizer locatedin the control room. The X-Band converter modules can betuned in 16 Hz steps over the entire 8000 to 8500 MHzfrequency band, supporting all existing and currently plannedearth resource satellites.

ViaSats MultifunctionDigital Receive System

MFDRS System isDesigned to FunctionTogether

Superior Reliabilityand Performance

Unrivaled Support ofRemote SensingDownlinks, with More

than 30 Bit SyncModules Available

Modular, ExpandableDesign

Bit Syncs Optimizedto Meet the SpecificNeeds of the SatelliteDown Link

Low Cost Approach toTrackingDemodulation


11/16




Model 924-7B IF DistributionThe Model 924-7B IF Distribution has been specificallydeveloped to compensate for the amplitude tilt typically causedby cable runs from the converter to the control room. This tiltcauses quadrature distortion (e.g., cross talk between the two

channels in the QPSK system) as well as some inter-symbolinterference distortion for the demodulated data.

This unit consists of a 19-inch rack chassis that is normallymounted in an equipment rack in the control room. The unitprovides amplitude equalization for up to 5 channels (data,track or test), distribution, and front-panel patching capability.

Model 924-1B DemodulatorThe data is routed from the IF Distribution Unit to Model924-1B Demodulators, where the data is coherentlydemodulated and routed to the bit synchronizer/signalconditioner (BSSC) units.

The Model 924-1B Demodulator operates with QPSK signals inthe 6 to 150 Mbps range, BPSK signals in the 3 to 85 Mbpsrange. Six each isolated I and Q output pairs are provided onthe rear panel of the demodulator for interconnection to theModel 924-2 Multiple BSSC Unit.

Both IEEE-488 and RS-232C remote control connectors areprovided on the rear panel. A rear-panel, 25-pin D connectorslaves the BSSC unit to the demodulator remote control so thatboth units are controlled by one remote interface.

Model 924-2 Multiple BSSCThe Model 924-2 Multiple BSSC, a companion to the924-1B Demodulator, contains power supplies, a multiplexerassembly, and up to six each QPSK BSSC modules and/orUQPSK BSSC modules.

This multiple BSSC concept allows operation with multiplesatellites but allows performance and operational formatoptimization for any given satellite. It also provides thecustomer the opportunity to procure capability in increments orall at once in a cost-effective manner.

ViaSat's preeminent position in the design of remote sensingsystems has resulted in the largest selection of developed, off-

the-shelf custom bit synchronizer plug-ins for the MFDRSproduct. ViaSat has more than 30 designed and fielded bitsynchronizer modules to choose from. Each of these bitsynchronizers has been designed to optimize systemperformance by taking into account the differential coding andbandpass filtering on board the spacecraft


12/16




Station Control Software

The state-of-the-art control and monitoring capabilities includedin ViaSat systems have been conceived, developed andrigorously tested over the many years that ViaSat has beendelivering ground stations. The features offered in this productare the result of a program of constant product enhancementinvolving both our own and our customers experiences.

Satellite TrackingThe station control software provides for completely automatedsatellite tracking operations. This software includes thefollowing key functions:

Mission Planning An event scheduling utility that allows theoperators to plan and schedule tracking events up to 7 days inadvance, for up to 50 different user specified satellites, witheasy to use schedule conflict resolution tools.

Automated Satellite Pass A fully automated satellite passfunction. Prior to the pass, the system configures theinstrumentation, and positions the antenna to the optimumposition for the start of the pass. Once the scheduled pass hasstarted, the SGP4 orbit prediction software points the antennato the satellite until sufficient signal strength is received toengage the autotrack system. Even while the system is

Key Features

ViaSats ground stationsoffer the most advancedand most widely testedcomputer control andmonitoring systemavailable for automatedremote sensingapplications. The systemincorporates a powerfuland field-proven

computer hardware andclient-server architecturesoftware package. Thispackage optimizesoperational reliability andminimizes operationalpersonnel costs with thefollowing key features:

Developed for bothUnix and Windows-NT

CompletelyAutomated Operation

Automated SystemTesting

Remote ComputerControl

Intuitive UserInterface for LocalOperation

The ground stationcontrol system

contains a completesuite of functions that

provide automatedoperation of the

system


13/16




autotracking the target, the system continues to calculatepredicted pointing angles. The system reverts to programtracking with the predicted angles if there is a signal blockageor fade, reacquiring the autotrack signal any time the signalstrength is sufficient to engage the autotrack system.

Post Pass Analysis A record of the antenna pointing angles,and critical receiver status is maintained through out the pass.This data can be analyzed after the pass to determine systemand pass effectiveness.

System TestingThe software system has a complete set of automated tests toassess the readiness of the system. Results are displayed ineasy to understand graphical format and/or numericalcomputations. The tests include:

G/T Test An automated direct measurement of system G/Tusing a celestial source adequate for the frequency band. Thistest requires optional power meter hardware.Pedestal Motion Tests Tests are provided to measure thelarge and small step response of the servo system, and thevelocity constant (Kv) and acceleration constant (Ka).

Bit Error Rate Test A complete end-to-end automated BERtest of the system that uses optional BER test equipment, andtest inject points in the feed prior to the LNA.

RF Boresight Tests Tests are provided to measure the autotrack jitter, snap on performance, and error gradient.

Instrument ControlThe software system provides real time control and statusindications from all the instruments. Through easy-to-use pointand click screen, the operator or the remote interface hasaccess to all critical system parameters in real time.

Remote OperationThe ground station software offers a remote interface foroperation in a completely unattended fashion. Through thisinterface, an external computer can schedule satellite passes,perform system tests, and gain instrument status. If the stationcontroller is on the Internet, the system can be operated from

virtually any location in the world.

Data Base FunctionsA complete set of data base functions required to operate acomplex system is provided, including: Ephemeris, Schedule,System Configuration Files, Pass Logs, Test Logs, and others.

Human/MachineInterface

Implemented usingX-Windows and

MOTIF Displays can be

remoted to anycomputer attached tothe same local-area-network

Real-time control andstatus of systeminstrumentation

Satellite schedulingtool supports

scheduling up to 7days in advance

Top Level heads updisplay providessummary status forentire system.Quickly drawsattention to criticalproblems for furtherinvestigation

Screens designedaround system

functions rather thanindividualinstruments

Intuitive interface foroperators, designedby operators overseveral years

Point and clickoperation

The Human-to-

Machine Interfaceincorporates theknowledge and

customer feedbackobtained over themany years that

ViaSat systems havebeen deployed


14/16




Control Subsystem

The control subsystemconsists of all equipmentrequired to control andmonitor the operation ofthe pedestal andantenna. In particular, itincludes the hardwareand firmware used to close the pedestal servo loops and tocontrol and monitor the antenna feed electronics. The PWMpower amplifiers, motors, tachometers, brakes, torque limiters,gearboxes, and data packages are all located in thepedestal/base extension, while the remainder of the servo

control circuitry is contained in the Model 3862 DigitalController.

Model 3862 Digital ControllerThe Model 3862 Digital Controller is a microprocessor-basedinstrument which provides antenna operation, status indication,and pedestal control. The controller has a display to showcommanded and actual position angles, pedestal operatingmodes, pedestal status, a data entry section for modification ofsystem operating parameters; and hand wheels for manualpositioning.

The Model 3862 Digital Controller implements full digital servoloop closure and compensation in all control modes. Since theentire servo process is executed in the control unit's firmware,the problems usually encountered with drifts and offsets inanalog compensation are totally eliminated.

The controller generates drive signals for the autotrackmodulator in the feed and receives signal strength andautotrack video information from the tracking receivers. Itprovides controls for manual or automatic mode selection suchas automatic target acquisition and polarization or frequencydiversity.

Model 924-9B AM DemodulatorThe Model 924-9B AM Demodulator is an amplitude modulation(AM) detector that is used for determining the antenna-generated amplitude of the tracking error signal. When used inconjunction with the Model 3862 Antenna Control Unit, the 924-9B AM Demodulator provides satellite autotracking capabilitiesduring a satellite pass.

Control SubsystemFeatures

Full state-of-the-artdigital control servoalgorithms providedrift-free, robustservo controls withno operatoradjustments

Advanced statemodel dynamicequalizationalgorithms providehigher precisiontracking performanceand lower signaldegradation

The Model 924-9B AM

Demodulator whenused with the Model3862 Antenna ControlUnit provides asimple and low costsolution for satellitetrackingdemodulation


15/16




Services

System Acceptance TestsViaSat provides an extensive testing program to verify theoperational performance of the systems before delivery to thecustomers. Customers are welcome to participate or witness allof the testing. Test plans and procedures are provided to thecustomer prior to the test. Testing can include:

In-Process and Subsystem Integration Factory Acceptance Test On-site Acceptance Test

Operation and Maintenance ManualsViaSat delivers a complete set of manuals with the system. Asystem manual covering system-level concepts, descriptions,block diagrams and interconnection as well as general systemoperating information is provided to familiarize maintenanceand operational personnel with the system. Individual unitmanuals are provided to aid the unit operation and basictroubleshooting.

TrainingViaSat realizes the important role that operations andmaintenance training play in the successful operation of a

remote sensing ground station. For this reason ViaSat offers acomprehensive training courses in Atlanta and/or at thecustomers site that will cover completely the preventive andrestorative maintenance as well as operation of the system.

InstallationViaSat can install and stage the system at its final location. Thisinstallation will include a complete functional check of thesystem to ensure that no damage has occurred during transitand installation. At the completion of installation siteacceptance tests are performed to verify all system criticalparameters.

ServiceViaSat offers an extensive service plan that can be tailored tomeet the requirements of our individual customers. We offerspare and repairs, field service and call in centers to aid inimmediate questions or system problems.

ViaSat Offers aComplete Package of

Services

Testing at criticalstages of systemdevelopment andstaging

Manuals that areeasy to understand,designed for theoperators andmaintenancepersonnel

Complete andcomprehensivetraining taught by thepeople that designedand built the system

Expert installationperformed by themechanics andengineers that builtthe system

Available postwarranty supportincluding a fullservice help desk,spares, repairs, andupgrades

ViaSat is committed toproviding quality

products andsupporting those

products for manyyears


16/16



System PerformanceSatellites

OrbitsInclinations

LEO > 450 km, GEOPolar

Coverage Hemispherical, No Keyholes

Tracking Autotrack and Program Track

Data Channels 1, Expandable

Frequency 8000 to 8500 MHz

G/T (See Note 1) 35.0 dB/K

BER (See Note 2) < 2.5 dB QPSK< 3.0 dB AQPSK

AccuracyAutotrackingPointing

0.05 rms (See Note 3) 0.10 rms

AntennaConfiguration 9.1-meter Cassegrain

Polarization RHC

3 dB Beamwidth 0.25, Nominal

Axial Ratio 1.5 dB Max 1.0 dB Typical

PedestalConfiguration Elevation / Azimuth / Tilt

Travel LimitsPrimary

Secondary

Elevation-1 +181

-4 +184

Azimuth 360 370

Tilt 2.5

Safety Fail-Safe ElectromechanicalBrakesInterlocks on Pins, HandCranks, Brakes, and AccessDoorsOverall Pedestal Disable

Max VelocityMin Acceleration

Azimuth22/s20/s 2

Elevation6/s

10/s 2

X-Band Data ReceiversTuningResolution

16 Hz

Intermediate

Frequency

720 MHz

DemodulationTypes

QPSK, UQPSK, SQPSK, BPSK,AQPSK

DemodulationRates

6 to 150 MB/s, QPSK3 to 85 MB/s, BPSK

Bit Syncs Customer Selected, Expandable

Outdoor EnvironmentalTemperature

OperationalStorage

-30 C to +55C-40 C to +55C

Rain TropicsWind

OperationalSurvival

75 km/hr Gusting to 85 km/hr200 km/hr, sustained

AltitudeOperationalStorage

Sea level to 3000 metersSea level to air transport

Indoor EnvironmentalTemperature

Operational

Storage

+15 C to +30C

-20 C to +55CRelative Humidity 20% to 80% non-condensing

PowerPedestal 120/208 V ac or 220/380 V ac,

50/60 Hz, 5 wire wye, 60 kVA

IndoorEquipment

100-240 V ac, 50/60Hz SinglePhase, Single 20 amp service

Notes:1. G/T at 5 elevation, 23C ambient temperature, and

clear sky conditions, 8000 MHz, No Options2. Differentially coded QPSK theoretical curve,

10 -2 < BER < 10 -6

3. Wind 75 km/hr gusting to 85 km/hr, 700 km Orbit,RIP Density 150 dBm/MHz.

Notice: Specifications Subject to Change Without Notice

Documents

9.1m Product Description