Actualization Analysis of LEO Opportunistic Doppler Aided GNSS Precise Point Positioning Using Moving Horizon Estimation

As the promising advantages, which are spectral and geometric diversity as well as the fast orbital velocity and high received signal power, the signal of opportunity (SoOP) of low-earth-orbit (LEO) satellite is used to assist the Global Navigation Satellite Systems (GNSS) in obscured and denied scenarios. We propose an LEO doppler-aided GNSS (LaGNSS) observation model for precise point positioning (PPP). Subsequently, to solve the problem that the weights of LEO satellites mismatch their actual process noises, we introduce an adjusted moving horizon estimation (AMHE) strategy to optimize the positioning performance. Thereafter, the Cramer-Rao lower bound (CRLB) is derived to verify the availability of LaGNSS and evaluate the theoretical position accuracy. Finally, the GPS and Orbcomm joint field experiments are used to analyze the suitable application scenarios for LaGNSS using the AMHE algorithm. The experimental results show that the robustness and applicability of AMHE are better than those of extended Kalman filter (EKF) for LaGNSS when the GPS satellites are insufficient.