Adapting commercial satellites to military communication needs

Increased reliance on commercial equipment by the military is necessary in today's defense environment. Potential cost reductions due to leveraging off the commercial satellite communication (satcom) base are a strong factor in planning for future military satcom (milsatcom) systems. Commercial satcom services are being extended to the "Ka" frequency band (30/20 GHz) to accommodate increasing demands for higher throughput and smaller ground terminals. Similar demands are being made of milsatcom systems. Military unique requirements for jam resistance, however, will likely precipitate the need to modify commercial designs. This paper describes a simple approach to add interference protection to a notional, broadband, transparent Ka-band satellite built for commercial satcom needs. Frequency hopping and channelized filtering of individual signals are added on-board the satellite, while signal processing is done on the ground. Unlike current advanced milsatcom designs, the signals are not demodulated on the satellite. Antenna nulling could also be added, if necessary, to the beam-shaping antennas. Two operational modes could be incorporated. In the wide-band mode, the payload can provide commercial-like high-data-rate and direct broadcast services. In the anti-jam hopping mode, the satcom payload is compatible with existing medium-data-rate military processing terminals. With individual satellite channels dedicated to each user network, network control is simplified through elimination of the need for power balancing among simultaneous users of the same wideband transponder.