9.1m Product Description

Product Description 9.1-Meter Remote Sensing Ground Station

ViaSat Satellite Ground Systems 8 October 2001

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9.1-Meter Remote Sensing Ground Station

History and Experience ViaSat’s Experience ViaSat has over 30 years experience in designing, building and installing full motion, high performance Remote Sensing Antenna Systems, and continues to lead the way in innovation and product development

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

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

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In 1984, on-going development resulted in the world’s first Multi-Function Digital Receive System (MFDRS), which was installed as part of a 10 meter S- and X-Band system atop an 8-story building in Fairbanks, Alaska. This system enabled reception of data from multiple satellites with the maximum use of common hardware and has since been used in all ViaSat ground stations.

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By 1989, ViaSat’s expertise in servo mechanism and control systems design heralded the first system in the world to acquire and track Remote Sensing Satellite signals at XBand, in the 10 meter CLIRSEN system in Ecuador.

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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 ground stations. All have the capability to receive data up to 320 Mbps.

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

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As a result of ViaSat’s success in the delivery of all of Motorola’s 57 IRIDIUM Ka-Band Gateway and TT&C terminals, a derivative of that system’s X/Y pedestal design was fielded in 1996 for the first time in a mobile remote sensing ground station to support the IKONOS program.

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

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In 2000, ViaSat was awarded a contract to provide the first 5.4m Ka-Band Remote Sensing Ground Station in support of NASA’s Ka-Band RSGS experiments.

Product Description www.viasat.com

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4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

ViaSat Remote Sensing Ground Stations – World Wide Deployment

World Wide Experience ViaSat has provided more than 60 Remote Sensing Ground Stations throughout the world, in all locations ranging from the tropics to the Arctic and Antarctic ViaSat has provided more Remote Sensing Ground Stations than all other suppliers Design, Manufacture and Test

Complete Stations Major Subsystems

ViaSat designs, manufactures and tests all of the major components and subsystems within ViaSat. Other companies sub-contract large portions of the system to outside vendors

Test and Integration

ViaSat has a world-class 140-acre test and integration facility where the systems are fully tested prior to shipment. No other supplier has this capability Company Reputation

• • • •

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

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ViaSat has built its reputation by supplying quality products and services at competitive prices, and by providing superior customer service before, during and after contract award

Product Description

4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

System Overview Key System Features •

ViaSat’s advanced 9.1-meter stretch formed aluminum reflector.

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Sufficient link margin to support all current and planned remote sensing satellites.

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ViaSat’s Model 3316A has a long history of providing reliable performance over many years of operation.

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Tilt Axis permits direct overhead tracking of polar satellites without loss of data.

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ViaSat’s Multifunction Digital Receive System (MFDRS) equipment. This system uses hardware field proven with more than 25 satellites. ViaSat’s 9.1-meter system provides a technically superior approach for remote sensing missions

The ViaSat 9.1-meter system employs many elements of technology fielded and proven in remote sensing ground terminal environments to provide an approach that is easy to install and provides state-of-the-art performance. The ViaSat 9.1 meter Remote Sensing Ground Station (RSGS), consists of several subsystems. The following paragraphs provide a brief overview of the system.

Antenna Subsystem The antenna consists of a ViaSat 9.1-meter dual shaped reflector and Cassegrain feed. The antenna subsystem has been designed to easily accept an upgrade of an S-band prime focus feed and dichroic subreflector in the future. The Cassegrain feed produces both tracking and data outputs. The high efficiency dual shaped reflector coupled with state-ofthe-art GaAs FET low-noise amplifiers provide a G/T of better than 35 dB/K at 5 degrees elevation. This performance will permit operation with any of the current and planned remote sensing satellites.

Pedestal Subsystem The antenna is installed on a Model 3316A Pedestal featuring dual, torque-biased, servo drives as well as an east-west tilt axis. This configuration provides full hemispherical coverage for remote sensing satellite tracking. The pedestal system is mounted on a 4.6-meter base extension that provides adequate ground clearance for safety of personnel and equipment.

X-Band Receive Subsystem The heart of the X-Band receive system is the ViaSat Multifunction Digital Receive System (MFDRS). This system of down converters, receivers, bit synchronizers and optional test equipment are designed to provide optimum system bit error rate (BER) performance under all conditions. The MFDRS product has been field proven with more than 25 remote sensing satellites.

Product Description www.viasat.com

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4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

CABLE RUN (50m)

I

720 MHz

DATA D/C

EQ

Track 8.0 - 8.5 GHz

TRACK D/C

Q

DEMOD 924-1B

3

M&C

720 MHz

3

EQ

SPARE

SPARE

SPARE

SPARE

SPARE

BSSC CHASSIS 924-2

SPARE

Data 8.0 - 8.5 GHz

M&C

EQ

720 MHz

SPARE

DATA D/C

AUTOTRACK

I Q

DEMOD 924-1B

SPARE

CASSEGRAIN X-BAND RECEIVE ONLY FEED (RHCP)

1

EQ

1

WIDEBAND BERT

1

SPARE

720 MHz

TEST U/C

PWR/ CTRL

DATA CLOCK

SPOT 1,2,4

Test 8.0 - 8.5 GHz

IF DIST UNIT 924-7B

CONV ASSY 924-4

TEST MODULATOR 924-6B

SPARE

PWR

CONTROL ROOM

SPOT 1,2,4

BASE EXTENSION EQUIPMENT

BSSC CHASSIS 924-2

I CH DATA & CK Q CH DATA & CK COMB DATA & CK

I CH DATA & CK Q CH DATA & CK COMB DATA & CK

3

Dry Air

POWER METER

EQ

SPARS AND SOLID SUBREFLECTOR

REFLECTOR

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PART OF BER TEST OPTION

2

PART OF POWER METER OPTION

3

PART OF 2nd RECEIVE CHAIN OPTION

2

DEHYDRATOR

PWR & CTRL

3 AXIS PEDESTAL (EL/AZ/TILT) 3316

DC POWER SUPPLIES

FREQUENCY SYNTHESIZER

PWM SERVO AMPS

FREQUENCY SYNTHESIZER

AC POWER CONTROL SIGNAL DISTRIBUTION POWER DISTRIBUTION

BASE EXTENSION

SERVO CONTROL EQUIPMENT

ANTENNA CONTROL UNIT OUTDOOR

NETWORK TIMESERVER

STATION CONTROLLER 3

COLOR MONITOR

FREQUENCY SYNTHESIZER

WB AM DEMOD 924-9B

GPS

COMPUTER OPERATING SYSTEM

KEYBOARD & MOUSE

APPLICATION SOFTWARE

ANTENNA CONTROL UNIT INDOOR

DISK DRIVE

PROTOCOL ADAPTER PROTOCOL ADAPTER

ETHERNET HUB

CDROM

AC POWER

Ext Computer

Control Subsystem ViaSat’s Series 3860 Antenna Control Unit (ACU) is a state-ofthe-art system that implements digital control servo algorithms with advanced state model dynamic equalization algorithms to provide unparalleled system pointing and tracking accuracy.

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

Full digital control over a dual drive torque-biased servo system

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Highly reliable DC servo drive system into a high efficiency gearing system

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Fully automated software control system that minimizes human error during mission critical operations

Station Control Software ViaSat’s ground stations offer the most advanced and most widely tested computer control and monitoring system available for automated remote sensing applications.

Key System Features

This multi-platform capable package has been continually improved since its inception nearly a decade ago. The software provides extensive system automation including hands off satellite pass operation, fully automated system testing, and remote control from other computer systems. ViaSat will gladly customize the software to meet specific customer needs.

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ViaSat’s 9.1-meter system is fully automated and designed for unattended operation

Product Description

4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

Antenna Subsystem

The main features of ViaSat’s antenna •

Highest performing G/T in its class

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Precision, high quality, shaped main reflector and subreflector

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High Efficiency X-Band Feed

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Operates across entire band without the need for phase adjustments

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Lightning rods and aircraft warning lights are provided on the upper edge of the reflector and the end of the spars

The utilization of existing standard designs allows ViaSat to propose a costeffective design that will support all known and currently planned Remote Sensing Satellites

ViaSat's High Efficiency Dual Reflector X-band Remote Sensing Antenna offers a field-proven system that provides excellent G/T across the 8000 to 8500 MHz band. The geometry allows for the independent optimization of the X-band Cassegrain antenna performance and the expansion and independent optimization of the prime focus S-band antenna.

Reflector The reflector design is a dual shaped surface, derived using proven aperture distributions and surface shaping techniques that ViaSat has successfully applied to reflectors ranging from 3 meters to 18 meters in diameter. The all-aluminum reflector consists of a 1.83-meter-diameter aluminum hub, 24 aluminum trusses and 48 aluminum inner/outer panels. The heart of the reflector is the allaluminum central hub that provides the necessary interfaces with the pedestal system and the X-band feed. The interior of the hub is spacious and provides ample room for system component mounting. The panels are manufactured at ViaSat using high-precision stretch-form tooling and assembly techniques.

Product Description www.viasat.com

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4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

Subreflector and Spar Assembly The subreflector assembly consists of a shaped solid subreflector and mount, optimized for high efficiency and antenna performance. The subreflector is supported by four sturdy aluminum spars of rectangular cross section, and is attached to the spars by means of the subreflector mount. The subreflector focusing and alignment procedure is performed once at the factory. The subreflector is then secured and dowel pinned in position to preclude the need for future adjustment.

X-Band Feed ViaSat’s X-band Cassegrain feed operates across the 8000 to 8500 MHz frequency band and is designed to maximize G/T across the band. All feed components are housed in a pressurized and heated feed enclosure that prevents moisture ingress and ice adhesion. The autotracking feed is a 5 horn array with ViaSat’s MONOSCAN1 single channel monopulse tracking technique. This tracking method achieves performance superior to systems that employ higher-order mode tracking schemes since the correct operation of higher order tracking schemes is highly dependent on the incoming signal polarization.

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

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Key Feed Features •

Cassegrain feed configuration

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High efficiency, low loss corrugated horn

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RHC polarization network

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Sloped septum polarizer for superior axial ratio polarization performance

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State-of-the-art uncooled low-noise amplifiers provide greater than 55 dB gain and 50K noise temperature

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Test injection coupler prior to the LNA

MONOSCAN® is a registered trademark of ViaSat, Inc.

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Product Description

4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

Pedestal Subsystem Key Features •

Azimuth and elevation have dual drives for high torque and zero backlash

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Elevation stows have strength for high wind conditions

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Tilt axis permits overhead orbits to be tracked without loss of data

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Brushless DC servomotors linked to turntables by high efficiency spur gears

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Fail safe brakes and hand drives are used

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Turntables with center holes for cable and waveguide passage

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Integrated, Dual resolver and limit switch assemblies

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Resolvers are geared at a 1:1 ratio and 64:1 ratio to the turntable through a precision antibacklash geartrain.

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4.6m environmentally controlled base extension elevates the pedestal and houses system equipment

The system employs a three-axis pedestal consisting of Model 3316A elevation-over-azimuth pedestal on top of an east-west tilt axis. This configuration provides full coverage of remote sensing satellites with no keyhole. ViaSat’s Model 3316A Pedestal is a robust configuration that is uniquely suitable for a remote sensing ground station. It features dual, torque-biased servo-drives in the azimuth and elevation axes. In the elevation axis both turntables are driven, rather than just one, to keep the reflector hub from having to distribute the elevation torque between turntables.

Model 3316A Elevation over Azimuth Pedestal The Model 3316A was created for the purpose of handling 10and 11-meter parabolic reflector antenna systems under high wind conditions and other adverse environments without the need for a radome. The Model 3316A features include high accuracy, reliability, safety, and convenience, with a complete line of solid-state control systems and accessories. All portions of the Model 3316A Servo-driven Pedestal system are of existing field-proven design and are in continuing production at ViaSat. The basic pedestal design provides a completely weatherproof unit with extremely high rigidity. All rotating components are sealed to keep out blowing sand, dust and water. Heavy-section steel weldments serve as basic structural members and also as the weatherproof exterior. Internal components can be reached through access doors or easily removable access covers, and the pedestal is self-draining to prevent accumulation of condensed moisture. Finishes are carefully applied to prevent corrosion due to adverse environments such as salt air. All electronic equipment and/or enclosures are configured to prevent the entry of water. Two dc continuous-duty bi-directional servomotors are used in the azimuth and elevation axes. The drive motors are built to ViaSat’s specifications with special consideration given to smooth low-speed operation, high-temperature operation, and

Product Description www.viasat.com

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4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station bi-directional control, limited maintenance and long life. These motors are torque biased to remove any backlash in the system. 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 manual pedestal operation. A pedestal disable switch is located at the pedestal base to allow complete power removal from the pedestal drives. A cable wrap is used to support the travel extremes of the pedestal. The cable, for both RF and control signals, is selected for flexibility and life under extreme operating conditions.

Tilt Mechanism The pedestal tilt mechanism serves to tilt the vertical reference axis of the tracking pedestal by an amount sufficient to avoid loss of signal from a satellite due to the zenith gimbal singularity that occurs during an overhead or near-overhead pass. The tilt mechanism assembly is constructed of two rigid steel weldments, designated the upper and lower tilt mechanism sections. This lower section mounts to the foundation or atop a base extension. The upper section provides mounting for the pedestal and tilts with the pedestal. The upper and lower sections are connected by a set of two pillow-block bearings and a set of two jackscrew actuators. A 3-phase AC reversible motor through a worm gear reducer simultaneously drives the actuators. Synchro and limit packages are provided for position feed back and limit detection.

Base Extension The base extension elevates the pedestal to the proper height to provide adequate ground clearance for the antenna reflector. The base extension is a rigid steel weldment providing a stiff operating base for the pedestal. The base extension has a flange with 12 bolt holes for rigidly mating the base extension to studs located in the customer-supplied foundation. The base extension provides an environmentally controlled space 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-lit working space within the base extension for basic maintenance and troubleshooting. There are access ladders both inside and outside the base extension that provide access to the pedestal, tilt mechanism and antenna hub area.

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Pressurization The feed and electronics enclosures are supplied with dry pressurized air from a pressurization system consisting of a dehydrator unit and associated dry air distribution piping. The dehydrator unit intakes and dehumidifies air by means of regenerative desiccant towers. The distribution system supplies this dry, pressurized air to all components requiring pressurization.

Product Description

4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

Multifunction Digital Receive System ViaSat’s Multifunction Digital Receive System •

MFDRS System is Designed to Function Together

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Superior Reliability and Performance

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Unrivaled Support of Remote Sensing Downlinks, with More than 30 Bit Sync Modules Available

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Modular, Expandable Design

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Bit Syncs Optimized to Meet the Specific Needs of the Satellite Down Link

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Low Cost Approach to Tracking Demodulation

For two decades, the great majority of remote sensing ground stations deployed throughout the world have employed ViaSat's Series 924 Multifunction Digital Receive System (MFDRS). During this period of time we have continued to refine the MFDRS equipment and to add the capability to receive data from each new family of remote sensing satellites as it is introduced. The versatility and modularity of this system are exemplified in the fact that more remote sensing satellites are currently supported with Series 924 equipment than with any other suppliers systems. The reasons for the high level of acceptance of this system are: •

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

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The modular design permits ground stations to support multiple families of remote sensing satellites with a minimum amount of equipment.

As a result of the superior nature of this system, several satellite designers have asked ViaSat to provide the inaugural receive system for their remote sensing satellites. Recent examples of this liaison are Radarsat, Landsat-7, IKONOS and Orbview. This close relationship between ViaSat and the designers/operators of remote sensing satellites has resulted in the incorporation of numerous subtleties in the design of the Series 924 equipment that is available nowhere else.

Model 924-4 Converter The X-Band signals are routed from the feed to the Model 924-4 converter. This unit, an integral part of the MFDRS product line, translates the X-Band signals to an IF of 720 MHz. The converter unit is a waterproof pressurized chassis. The chassis is typically located in the hub or on the pedestal riser. By down converting the signals to a lower frequency near the feed, 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 of the Model 924-4 family. Each converter module can have a separate phase-locked source that can be tuned independently from a commercial off the shelf frequency synthesizer located in the control room. The X-Band converter modules can be tuned in 16 Hz steps over the entire 8000 to 8500 MHz frequency band, supporting all existing and currently planned earth resource satellites.

Product Description www.viasat.com

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4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

Model 924-7B IF Distribution The Model 924-7B IF Distribution has been specifically developed to compensate for the amplitude tilt typically caused by cable runs from the converter to the control room. This tilt causes quadrature distortion (e.g., cross talk between the two channels in the QPSK system) as well as some inter-symbol interference distortion for the demodulated data. This unit consists of a 19-inch rack chassis that is normally mounted in an equipment rack in the control room. The unit provides amplitude equalization for up to 5 channels (data, track or test), distribution, and front-panel patching capability.

Model 924-1B Demodulator The data is routed from the IF Distribution Unit to Model 924-1B Demodulators, where the data is coherently demodulated and routed to the bit synchronizer/signal conditioner (BSSC) units. The Model 924-1B Demodulator operates with QPSK signals in the 6 to 150 Mbps range, BPSK signals in the 3 to 85 Mbps range. Six each isolated I and Q output pairs are provided on the rear panel of the demodulator for interconnection to the Model 924-2 Multiple BSSC Unit. Both IEEE-488 and RS-232C remote control connectors are provided on the rear panel. A rear-panel, 25-pin D connector slaves the BSSC unit to the demodulator remote control so that both units are controlled by one remote interface.

Model 924-2 Multiple BSSC The Model 924-2 Multiple BSSC, a companion to the 924-1B Demodulator, contains power supplies, a multiplexer assembly, and up to six each QPSK BSSC modules and/or UQPSK BSSC modules. This multiple BSSC concept allows operation with multiple satellites but allows performance and operational format optimization for any given satellite. It also provides the customer the opportunity to procure capability in increments or all at once in a cost-effective manner. ViaSat's preeminent position in the design of remote sensing systems has resulted in the largest selection of developed, offthe-shelf custom bit synchronizer plug-ins for the MFDRS product. ViaSat has more than 30 designed and fielded bit synchronizer modules to choose from. Each of these bit synchronizers has been designed to optimize system performance by taking into account the differential coding and bandpass filtering on board the spacecraft

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Product Description

4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

Station Control Software Key Features ViaSat’s ground stations offer the most advanced and most widely tested computer control and monitoring system available for automated remote sensing applications. The system incorporates a powerful and field-proven computer hardware and client-server architecture software package. This package optimizes operational reliability and minimizes operational personnel costs with the following key features: •

Developed for both Unix and Windows-NT

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Completely Automated Operation

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Automated System Testing

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Remote Computer Control

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Intuitive User Interface for Local Operation

The ground station control system contains a complete suite of functions that provide automated operation of the system

The state-of-the-art control and monitoring capabilities included in ViaSat systems have been conceived, developed and rigorously tested over the many years that ViaSat has been delivering ground stations. The features offered in this product are the result of a program of constant product enhancement involving both our own and our customers experiences.

Satellite Tracking The station control software provides for completely automated satellite tracking operations. This software includes the following key functions: Mission Planning – An event scheduling utility that allows the operators to plan and schedule tracking events up to 7 days in advance, for up to 50 different user specified satellites, with easy to use schedule conflict resolution tools. Automated Satellite Pass – A fully automated satellite pass function. Prior to the pass, the system configures the instrumentation, and positions the antenna to the optimum position for the start of the pass. Once the scheduled pass has started, the SGP4 orbit prediction software points the antenna to the satellite until sufficient signal strength is received to engage the autotrack system. Even while the system is

Product Description www.viasat.com

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4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station autotracking the target, the system continues to calculate predicted pointing angles. The system reverts to program tracking with the predicted angles if there is a signal blockage or fade, reacquiring the autotrack signal any time the signal strength 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 system and pass effectiveness.

Human/Machine Interface •

Implemented using X-Windows and MOTIF

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Displays can be remoted to any computer attached to the same local-areanetwork

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Real-time control and status of system instrumentation

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Satellite scheduling tool supports scheduling up to 7 days in advance

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Top Level heads up display provides summary status for entire system. Quickly draws attention to critical problems for further investigation

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Screens designed around system functions rather than individual instruments

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Intuitive interface for operators, designed by operators over several years

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Point and click operation

System Testing The software system has a complete set of automated tests to assess the readiness of the system. Results are displayed in easy to understand graphical format and/or numerical computations. The tests include: G/T Test – An automated direct measurement of system G/T using a celestial source adequate for the frequency band. This test requires optional power meter hardware. Pedestal Motion Tests – Tests are provided to measure the large and small step response of the servo system, and the velocity constant (Kv) and acceleration constant (Ka). Bit Error Rate Test – A complete end-to-end automated BER test of the system that uses optional BER test equipment, and test inject points in the feed prior to the LNA. RF Boresight Tests – Tests are provided to measure the auto track jitter, snap on performance, and error gradient.

Instrument Control The software system provides real time control and status indications from all the instruments. Through easy-to-use point and click screen, the operator or the remote interface has access to all critical system parameters in real time.

Remote Operation The ground station software offers a remote interface for operation in a completely unattended fashion. Through this interface, an external computer can schedule satellite passes, perform system tests, and gain instrument status. If the station controller is on the Internet, the system can be operated from virtually any location in the world.

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

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The Human-toMachine Interface incorporates the knowledge and customer feedback obtained over the many years that ViaSat systems have been deployed

Product Description

4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

Control Subsystem

Control Subsystem Features

The control subsystem consists of all equipment required to control and monitor the operation of the pedestal and antenna. In particular, it includes the hardware and firmware used to close the pedestal servo loops and to control and monitor the antenna feed electronics. The PWM power amplifiers, motors, tachometers, brakes, torque limiters, gearboxes, and data packages are all located in the pedestal/base extension, while the remainder of the servo control circuitry is contained in the Model 3862 Digital Controller.

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Full state-of-the-art digital control servo algorithms provide drift-free, robust servo controls with no operator adjustments

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Advanced state model dynamic equalization algorithms provide higher precision tracking performance and lower signal degradation

Model 3862 Digital Controller

The Model 924-9B AM Demodulator when used with the Model 3862 Antenna Control Unit provides a simple and low cost solution for satellite tracking demodulation

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

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The Model 3862 Digital Controller is a microprocessor-based instrument which provides antenna operation, status indication, and pedestal control. The controller has a display to show commanded and actual position angles, pedestal operating modes, pedestal status, a data entry section for modification of system operating parameters; and hand wheels for manual positioning.

The controller generates drive signals for the autotrack modulator in the feed and receives signal strength and autotrack video information from the tracking receivers. It provides controls for manual or automatic mode selection such as automatic target acquisition and polarization or frequency diversity.

Model 924-9B AM Demodulator The Model 924-9B AM Demodulator is an amplitude modulation (AM) detector that is used for determining the antennagenerated amplitude of the tracking error signal. When used in conjunction with the Model 3862 Antenna Control Unit, the 9249B AM Demodulator provides satellite autotracking capabilities during a satellite pass.

Product Description www.viasat.com

14

4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

Services

ViaSat Offers a Complete Package of Services

System Acceptance Tests ViaSat provides an extensive testing program to verify the operational performance of the systems before delivery to the customers. Customers are welcome to participate or witness all of the testing. Test plans and procedures are provided to the customer prior to the test. Testing can include: •

In-Process and Subsystem Integration

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Factory Acceptance Test

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On-site Acceptance Test

Operation and Maintenance Manuals ViaSat delivers a complete set of manuals with the system. A system manual covering system-level concepts, descriptions, block diagrams and interconnection as well as general system operating information is provided to familiarize maintenance and operational personnel with the system. Individual unit manuals are provided to aid the unit operation and basic troubleshooting.

Training ViaSat realizes the important role that operations and maintenance training play in the successful operation of a remote sensing ground station. For this reason ViaSat offers a comprehensive training courses in Atlanta and/or at the customers site that will cover completely the preventive and restorative maintenance as well as operation of the system.

Installation ViaSat can install and stage the system at its final location. This installation will include a complete functional check of the system to ensure that no damage has occurred during transit and installation. At the completion of installation site acceptance tests are performed to verify all system critical parameters.

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Testing at critical stages of system development and staging

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Manuals that are easy to understand, designed for the operators and maintenance personnel

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Complete and comprehensive training taught by the people that designed and built the system

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Expert installation performed by the mechanics and engineers that built the system

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Available post warranty support including a full service help desk, spares, repairs, and upgrades

ViaSat is committed to providing quality products and supporting those products for many years

Service ViaSat offers an extensive service plan that can be tailored to meet the requirements of our individual customers. We offer spare and repairs, field service and call in centers to aid in immediate questions or system problems.

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Product Description

4356 Communications Drive, Norcross, GA 30093 USA

Tel: +1 678.924.2631

Fax: +1 770.935.3285

9.1-Meter Remote Sensing Ground Station

System Performance

X-Band Data Receivers

Satellites

Tuning Resolution

16 Hz

Intermediate Frequency

720 MHz

Demodulation Types

QPSK, UQPSK, SQPSK, BPSK, AQPSK

Orbits

LEO > 450 km, GEO

Inclinations

Polar

Coverage

Hemispherical, No Keyholes

Tracking

Autotrack and Program Track

Data Channels

1, Expandable 8000 to 8500 MHz

Demodulation Rates

6 to 150 MB/s, QPSK

Frequency G/T (See Note 1)

35.0 dB/K

Bit Syncs

Customer Selected, Expandable

BER (See Note 2)

< 2.5 dB QPSK < 3.0 dB AQPSK

Outdoor Environmental

3 to 85 MB/s, BPSK

Temperature

Accuracy Autotracking

0.05° rms (See Note 3)

Pointing

0.10º rms

Operational

-30°C to +55°C

Storage

-40°C to +55°C

Rain

Antenna Configuration

9.1-meter Cassegrain

Polarization

RHC

3 dB Beamwidth

0.25°, Nominal

Axial Ratio

1.5 dB Max

Elevation / Azimuth / Tilt

Travel Limits

Elevation

Azimuth

Tilt

Primary

-1° +181°

± 360°

± 2.5°

Secondary

-4° +184°

± 370°

Safety

Fail-Safe Electromechanical Brakes Interlocks on Pins, Hand Cranks, Brakes, and Access Doors Overall Pedestal Disable Azimuth

Operational

75 km/hr Gusting to 85 km/hr

Survival

200 km/hr, sustained

Altitude 1.0 dB Typical

Pedestal Configuration

Tropics

Wind

Elevation

Max Velocity

22°/s

6°/s

Min Acceleration

20°/s2

10°/s2

Operational

Sea level to 3000 meters

Storage

Sea level to air transport

Indoor Environmental Temperature Operational

+15°C to +30°C

Storage

-20°C to +55°C

Relative Humidity

20% to 80% non-condensing

Power Pedestal

120/208 V ac or 220/380 V ac, 50/60 Hz, 5 wire wye, 60 kVA

Indoor Equipment

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

Notes: 1.

G/T at 5° elevation, 23°C ambient temperature, and clear sky conditions, 8000 MHz, No Options

2.

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

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