Finding user position location using the Doppler information in satellite CDMA systems

This paper presents a new method for determining the position of a ground mobile using synthetic aperture radar (SAR) signal processing techniques in the low Earth orbit (LEO) communication satellite. The received signal in the satellite contains the information on the Doppler frequency shift resulting from the relative motion between the satellite and a mobile transmitter over observation interval as measurements. The position of the ground mobile can be obtained by processing the history of Doppler frequencies coherently. Simulation results demonstrating the capability of the proposed position determination method in satellite CDMA communication links are presented.