Study of satellite mobile communication systems for the coverage of polar regions

Satellite mobile communication systems for polar coverage complementary to the INMARSAT space segment were investigated. Services to be provided include low data rate communication, automated reception of distress calls, transmitted by emergency beacons (EPIRB), radio location of EPIRBs based on Doppler techniques, and voice communication. The systems use the L-band for links between satellites and mobiles, and the 4/6 GHz bands for feeder links. Seven systems with orbits varying between altitudes below the Van Allen Belt and inclined geosynchronous orbits were compared as to complexity; possibility of permanent contact to polar regions with or without intersatellite links; feasibility and quality of communication; and number of satellites and fixed Earth stations. The configuration selected is characterized by only three satellites in a circular polar orbit (12,000 km altitude) and 7 to 9 fixed Earth stations. The satellite payload can be simple and the system offers permanent contact without intersatellite links.