Mobile terminal positioning technique for dynamic satellite constellations

A mobile terminal positioning scheme in Non-Geostationary satellite constellation systems is presented. The scheme utilises the propagation delay and Doppler shifts experienced in such dynamic constellations. The various factors that affect the accuracy of a user position have been identified and thoroughly investigated; to demonstrate the user position accuracy results, an ICO-10 like satellite constellation was used with different measurement noise conditions. The scheme does not impose any additional signalling on the air-interface and the user position can be estimated at an LES with no assistance from the mobile terminal. It will also be shown that the positioning accuracy error is minimised when dual-satellite diversity is utilised. In this paper, we also discuss the applications of this user position information and its impact on management of mobility and resources. (C) 1998 John Wiley & Sons, Ltd.