Estimation of the Time Varying TDOA and FDOA in GEO-LEO Dual-satellites Location System

To solve the problem that can’t estimate the time varying TDOA (time difference of arrival) and FDOA (frequency difference of arrival) used to locate the interference source resulted from the high-speed movement characteristics of the low earth orbit satellite in Geo-Leo dual-satellites location system. It analyzed the variation of the radial distance difference relative to the interference source between the geostationary satellite and low earth orbit satellite, found it approximately matches Jerk model. Then it built the expressions of the two signals received by the two satellite platforms. After that, it discussed the influences to the envelope and carrier frequency of signals caused by the velocity difference, acceleration difference and jerk difference, showed what should be considered and what needn’t. Finally, it gave a method of joint estimation the time varying parameters for location, which is via suppressing the influence of movement parameters and based on the Cross Ambiguity Function (CAF). The results of simulations and experiments show it can eliminate the effects of movement parameters effectively, estimate the location parameters accurately, and the estimation accuracy of the TDOA and FDOA can approach the theoretical lower bound.