A Modified Particle Filter for Dynamic Multipath Mitigation in GPS Receivers

Abstract

AbstractTo the aim of mitigating the multipath effect in dynamic Global Positioning System (GPS) applications, an approach based on the channel dynamic model and the modified particle filtering technique is proposed, and the corresponding algorithm is integrated into GPS receiver tracking loops. The particle filtering mechanism builds upon the multipath channel measurements, and an increase in the number of correlator channel is required compared with conventional GPS receivers. A partical filter that employs the modified resampling algorithm based on an adaptive filter and the Recursive Least Square (RLS) algorithm is designed for the dynamic estimation of the multipath channel. Then the code and carrier phase receiver tracking errors are compensated by removing the estimated multipath components from the correlators’ outputs. To demonstrate the capabilities of the proposed approach, this technique is integrated into a GPS software receiver connected to a navigation satellite signal simulator, thus simulations under the controlled dynamic multipath scenarios can be carried out. Simulation results show that in a dynamic and fairly severe multipath environment, the proposed approach achieves simultaneously instantaneous accurate multipath channel estimation, and significant multipath tracking errors reduction in both code delay and carrier phase.KeywordsGPSDynamic multipath mitigationModified particle filteringAdaptive filteringRLS algorithm