Radio position determination by satellite

The recent allocation by the 1987 World Administrative Radio Conference of frequency bands for radio position determination (RPD) satellite service is taken as an indication that such systems will soon become widespread. The many parameters involved (type of ranging, type of multiple access, number of active satellites through which ranging signals are passed, etc.), are expected to result in tradeoffs producing systems differing in complexity and in the positioning accuracy. The author deals with the formulation of positioning fixes and the calculation of the associated positioning errors in the case of two- and three-satellite RPD systems using turnaround ranging. The results are expressed in normalized longitudinal, latitudinal, and circular horizontal positioning errors. They can be applied to the design of the RPD system geometry and used to establish ranging accuracy requirements for postulated positioning accuracy