Long-Baseline Differential Doppler Positioning Using Space-Based SOP Based on BPVGMM

Positioning based on low Earth orbit (LEO) satellites' signals of opportunity (SOPs) is an effective complement and backup positioning solution of global navigation satellite system (GNSS). The major sources of error that have to be considered in the positioning technology based on LEO satellites' SOP are ephemeris and satellite clock errors with space-time relevance. Although the differential positioning can effectively reduce the error, positioning error is still large due to the low orbit of the satellites in the long-baseline scenario. To address the aforementioned challenge, a differential Doppler positioning algorithm based on baseline projection vector geometric model modification (BPVGMM) is proposed. Simulation results show that the BPVGMM algorithm has significantly better accuracy in the long-baseline positioning case than the traditional algorithm, and the validity of the algorithm is verified by differential positioning experiments using signals from Iridium NEXT satellites.