Product Description
9.1-Meter Remote Sensing
Ground Station
ViaSat
Satellite Ground Systems 8 October 2001
History and Experience
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.
• 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.
• 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 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 ground stations. All have the capability to receive data up to 320 Mbps.
• Also in 1993, ViaSat delivered the first ever Landsat 7 AQPSK demodulator and bit synchronizer to the EROS Data Center.
• 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. • 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.
• 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.
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
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 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
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 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
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
System Overview
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-of-the-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.
Key System Features
• ViaSat’s advanced 9.1-meter stretch formed aluminum reflector.
• Sufficient link margin to support all current and planned remote sensing satellites. • ViaSat’s Model 3316A
has a long history of providing reliable performance over many years of operation. • Tilt Axis permits
direct overhead tracking of polar satellites without loss of data. • 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
Dry Air Data 8.0 - 8.5 GHz Test 8.0 - 8.5 GHz Track 8.0 - 8.5 GHz CONV ASSY 924-4 SERVO CONTROL EQUIPMENT DC POWER SUPPLIES PWM SERVO AMPS AC POWER CONTROL CONTROL ROOM BASE EXTENSION EQUIPMENT AUTOTRACK SIGNAL DISTRIBUTION DEHYDRATOR CASSEGRAIN X-BAND RECEIVE ONLY FEED (RHCP) REFLECTOR SPARS AND SOLID SUBREFLECTOR 3 AXIS PEDESTAL (EL/AZ/TILT) 3316 BASE EXTENSION PWR & CTRL PWR/ CTRL PWR IF DIST UNIT924-7B 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 POWER DISTRIBUTION FREQUENCY SYNTHESIZER FREQUENCY SYNTHESIZER FREQUENCY SYNTHESIZER CABLE RUN (50m) WB AM DEMOD 924-9B ANTENNA CONTROL UNIT OUTDOOR AC POWER COLOR MONITOR KEYBOARD & MOUSE STATION CONTROLLER DISK DRIVE CDROM COMPUTER OPERATING SYSTEM APPLICATION SOFTWARE TEST MODULATOR 924-6B DATA CLOCK 1 WIDEBAND BERT 1 GPS Ext Computer PROTOCOL ADAPTER ETHERNET HUB NETWORK TIMESERVER PROTOCOL ADAPTER POWER METER 2 PART OF POWER METER OPTION 2 PART OF BER TEST OPTION 1 PART OF 2nd RECEIVE CHAIN OPTION 3 3 1 I M&C I CH DATA & CK COMB DATA & CK Q CH DATA & CK Q DEMOD 924-1B BSSC CHASSIS 924-2 SPO T 1 ,2,4
SPARE SPARE SPARE SPARE SPARE
3 3
I
M&C
I CH DATA & CK COMB DATA & CK Q CH DATA & CK Q DEMOD 924-1B BSSC CHASSIS 924-2 SPO T 1 ,2,4
SPARE SPARE SPARE SPARE SPARE
ANTENNA CONTROL UNIT
INDOOR
3
Control Subsystem
ViaSat’s Series 3860 Antenna Control Unit (ACU) is a state-of-the-art system that implements digital control servo algorithms with advanced state model dynamic equalization algorithms to provide unparalleled system pointing and tracking accuracy. 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.
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.
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.
Key System Features
• Full digital control over a dual drive torque-biased servo system
• Highly reliable DC servo drive system into a high efficiency gearing system • Fully automated
software control system that minimizes human error during mission critical operations ViaSat’s 9.1-meter system is fully automated and designed for unattended operation
Antenna Subsystem
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 all-aluminum 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.
The main features of ViaSat’s antenna
• Highest performing G/T in its class • Precision, high
quality, shaped main reflector and
subreflector • High Efficiency
X-Band Feed • Operates across
entire band without the need for phase adjustments • 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 cost-effective design that will support all known and currently planned
Remote Sensing Satellites
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
MONOSCAN1 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
1 MONOSCAN® is a registered trademark of ViaSat, Inc.
Key Feed Features
• Cassegrain feed configuration • High efficiency, low
loss corrugated horn • RHC polarization
network
• Sloped septum polarizer for superior axial ratio polarization performance • State-of-the-art uncooled low-noise amplifiers provide greater than 55 dB gain and 50K noise temperature
• Test injection coupler prior to the LNA
Pedestal Subsystem
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 10- and 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
Key Features
• Azimuth and
elevation have dual drives for high torque and zero backlash • Elevation stows have
strength for high wind conditions • Tilt axis permits
overhead orbits to be tracked without loss of data
• Brushless DC
servomotors linked to turntables by high efficiency spur gears • Fail safe brakes and
hand drives are used • Turntables with
center holes for cable and waveguide passage
• Integrated, Dual resolver and limit switch assemblies • Resolvers are geared
at a 1:1 ratio and 64:1 ratio to the turntable through a precision anti-backlash geartrain. • 4.6m environmentally controlled base extension elevates the pedestal and houses system equipment
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.
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.
Multifunction Digital Receive System
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.
• 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.
ViaSat’s Multifunction Digital Receive System
• MFDRS System is Designed to Function Together • Superior Reliability and Performance • Unrivaled Support of Remote Sensing Downlinks, with More than 30 Bit Sync Modules Available • Modular, Expandable
Design
• Bit Syncs Optimized to Meet the Specific Needs of the Satellite Down Link
• Low Cost Approach to Tracking
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, off-the-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
Station Control Software
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
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 • Completely Automated Operation • Automated System Testing • Remote Computer Control • Intuitive User Interface for Local Operation
The ground station control system contains a complete suite of functions that
provide automated operation of the
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.
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.
Human/Machine Interface • Implemented using X-Windows and MOTIF • Displays can be remoted to any computer attached to the same local-area-network
• Real-time control and status of system instrumentation • Satellite scheduling tool supports scheduling up to 7 days in advance • Top Level heads up
display provides summary status for entire system. Quickly draws attention to critical problems for further investigation
• Screens designed around system functions rather than individual
instruments
• Intuitive interface for operators, designed by operators over several years • Point and click
operation The Human-to-Machine Interface incorporates the knowledge and customer feedback
obtained over the many years that ViaSat systems have
Control Subsystem
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.
Model 3862 Digital Controller
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 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.
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
antenna-generated amplitude of the tracking error signal. When used in conjunction with the Model 3862 Antenna Control Unit, the 924-9B AM Demodulator provides satellite autotracking capabilities during a satellite pass.
Control Subsystem Features
• Full state-of-the-art digital control servo algorithms provide drift-free, robust servo controls with no operator adjustments • Advanced state model dynamic equalization algorithms provide higher precision tracking performance and lower signal degradation
• 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
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 • Factory Acceptance Test
• 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.
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.
ViaSat Offers a Complete Package of Services • Testing at critical stages of system development and staging
• Manuals that are easy to understand, designed for the operators and maintenance personnel • Complete and
comprehensive training taught by the people that designed and built the system • Expert installation
performed by the mechanics and engineers that built the system
• 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
Satellites Orbits Inclinations
LEO > 450 km, GEO Polar
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 Accuracy Autotracking Pointing 0.05° rms (See Note 3) 0.10º rms Antenna
Configuration 9.1-meter Cassegrain Polarization RHC
3 dB Beamwidth 0.25°, Nominal
Axial Ratio 1.5 dB Max 1.0 dB Typical
Pedestal
Configuration Elevation / Azimuth / Tilt Travel Limits Primary Secondary Elevation -1° +181° -4° +184° Azimuth ± 360° ± 370° Tilt ± 2.5° Safety Fail-Safe Electromechanical
Brakes
Interlocks on Pins, Hand Cranks, Brakes, and Access Doors
Overall Pedestal Disable Max Velocity Min Acceleration Azimuth 22°/s 20°/s2 Elevation 6°/s 10°/s2 Tuning Resolution 16 Hz Intermediate Frequency 720 MHz Demodulation
Types QPSK, UQPSK, SQPSK, BPSK, AQPSK Demodulation
Rates 6 to 150 MB/s, QPSK 3 to 85 MB/s, BPSK
Bit Syncs Customer Selected, Expandable
Outdoor Environmental Temperature Operational Storage -30°C to +55°C -40°C to +55°C Rain Tropics Wind Operational Survival 75 km/hr Gusting to 85 km/hr 200 km/hr, sustained Altitude Operational Storage
Sea level to 3000 meters Sea level to air transport
Indoor Environmental Temperature Operational Storage +15°C to +30°C -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.
