GPS Multipath Mitigation Algorithm Based on Signal Separation Theory

The effect of signal multipath is one of the main reason which lead to positioning error in Global Positioning System (GPS). Although the differential technology can improve the positioning accuracy of the navigation system, but the reference stations and users being in different geographical environment, the differential GPS system still can’t eliminate the positioning error caused by multipath signal. In the light of the character of GPS multipath signal model, this paper presents a GPS time delay estimation algorithm based on signal separation theory. Firstly, carrier frequency is estimated when the signal delay is unknown. Then, we use the estimated carrier frequency to get signal delay information with signal separation theory. It can be shown from the simulation results that the method with high estimation accuracy has a good time delay and carrier frequency estimation performance and effectively mitigate the multipath. Comparing with the conventional method, new method has obviously advantages. It is even better than the narrow-band correlation algorithm in most cases.