Comparative Studies of GPS Multipath Mitigation Methods Performance

Coupled amplitude delay lock loops (CADLL) is a recently proposed multipath estimation and mitigation technique based on joint estimation of line-of-sight (LOS) and multipath signal amplitude, code phase, and carrier phase. The CADLL performance is evaluated against two widely known multipath mitigation methods: the high-resolution correlator (HRC), representative of the correlators combination methods, and the multipath mitigation technique (MMT), representative of multipath estimation methods. Multiple tests emulating various scenarios are performed to demonstrate that CADLL always generates better results than the other two methods. Additionally, CADLL has better noise performance, can estimate multipath signals using shorter integration time, and is capable of tracking dynamic multipath signals. Simulation tests using a statistical urban multipath signal model prove that CADLL is effective in estimating and mitigating multipath in severe multipath environments. These simulation results are further validated using satellite signals generated by Spirent Global Navigation Satellite System (GNSS) 6700.