Modular, programmable design of ViaSat High Rate modem meets the demands of remote sensing and earth observation missions.

Want to know where the next hurricane is going to hit, how many houses are in your neighborhood, will it rain today, or what the bad guys are doing half a world away? All of these burning questions can be answered provided a remote sensing satellite is gathering the information and a ViaSat High Rate (VHR) modem is receiving it.

The ViaSat High Rate (VHR) modem, VHR-400, was developed to meet the demanding requirements of the remote sensing and earth observation marketplace. This program was a joint collaboration between ViaSat’s Antenna Systems and ECC, bringing together our expertise in remote sensing antennas and high-data rate modems. Antenna Systems developed the specifications for the GeoEye and WorldView satellites. Our WINDS high speed burst modem was the basis for the modem design.

Primarily a demodulator performing one-way data transfers, the modem is the ground portion of the communications link for fixed and mobile platforms operating in the X- to Ka-bands. It delivers full coverage of the commercial remote sensing band, at data rates up to 400 Mbps QPSK for these applications:

• Meteorological, environmental, and agricultural applications using optical camera images
• Mapping of urban and “undeveloped” areas
• Radar sensing to support other meteorological applications such as wave height and wind speed determination
• National defense

Modular Design
With its modular, five-slot ATCA chassis the modem can be tailored to the individual requirements of each customer. By installing different circuit cards the modem fits different system configurations, and cards can be installed on site for upgrades in the field.

Customers can populate the modem with vari­ous combinations of demodulators, FEC decoders, and a test modulator. Configurations of the VHR-400 include zero, one, or two demodulators and zero or one modulator. The test modulator may be used to perform end-to-end bit error rate testing without the need for exter­nal test equipment.

Satellite configurations are preprogrammed for simple remote and front panel operation, and the modem is field programmable to accommodate newly defined future mis­sions. A LINUX-based operating system has a high degree of reliability and security from web-based threats.