GEOSTAR positioning analysis

The GEOSTAR Satellite System is designed to provide accurate position information to users in the United States. Computers in a central facility calculate the users' position based on the measurement of roundtrip signal transit times between the facility and the user transceivers, the signal returning through two geosynchronous satellites. The GEOSTAR System achieves high accuracy through the use of spread spectrum timing signals and operation in a differential mode. This paper discusses the GEOSTAR System positioning technique, error sources, and anticipated system accuracy.