Summary
A number of satellite system techniques have been suggested as candidates to provide ATC surveillance, communication, and/or navigation service over CONUS. All techniques perform postion determination by multilateration using a constellation of satellites. They can be categorized as follows: 1) Coordinated Aircraft-to-Satellite Techniques (CAST), 2) Random Access Aircraft-to-Satellite Techniques (RAST), and 3) Satellite-to-Aircraft Techniques (SAT). A technical assessment is made of the various techniques with no one particular technique emerging as superior; several feasible alternatives are identified. The assessment indicates that satellite bases techniques for CONUS ATC can be developed without relying on high risk technology. This volume deals with RAST, CAST and SAT are treated in companion volumes. A system employing RAST could operate by having each aircraft transmit a unique signature periodically, without any coordination of transmissions. The position of the aircraft is then obtained by multilateration using the arrival times of its signature at four or more satellites. Since aircraft transmissions are not coordinated, there is the possibility that different signatures may overlap at a satellite receiver. The resulting mutual interference is a factor in the performance of systems employing RAST. The critical technical aspects of RAST are explored with special emphasis on signaling formats, satellite coverage issues, degradation due to mutual interference and susceptibility to jamming.