Abstract: A navigation and mobile communication satellite system including a Geo-Mobile (GEM) satellite (14) and a plurality of Global Position System (GPS) satellites (50). The GEM satellite (14) is in operative communication with at least one ground segment (12) and at least one user segment (16), and includes a GEM processor for providing communication services to the user segments (16). The GPS network is also in operative communication with at least one of the user segments (16) and at least one of the ground segments (12). The GPS network provides navigation data to the user segment (16). Each of the ground segments (12) include a gateway station (28) for receiving the navigation data and uplinking the navigation data to the GEM satellite (14) such that the navigation data is rebroadcast to the user segments (16) at a higher power than from the GPS network alone. In this manner, the GEM system provides a navigation signal at a much higher power than the present GPS system.

Abstract: A satellite-based communication system providing high rate transfer of data between linked terminals. The system comprises a plurality of user terminals (VSAT's) that are linked by and that communicate with each other by way of a satellite-based relay system. A network control center provides configuration signals that control the satellite relay system and coordinate linking of terminals to each other. Frequency division multiplexing uplinks are used from the terminals and the network control center to the satellite relay system. Time division multiplexing are used on downlinks from the satellite relay system to the terminals and the network control center. Each user terminal comprises a data compression and decompression circuit, a transceiver, and an antenna for transmitting and receiving data to and from the satellite relay system. The satellite relay system comprises a satellite, a wide area antenna, a plurality of receive antennas, a plurality of transmit antennas, and a signal processor.