A Method of Carrier Phase Multipath Mitigation Based on Punctual Code Correlation Reference Waveform

摘要

Carrier phase multipath is one of the main sources of error for high-precision GNSS applications. In an urban environment with severe multipath fading, multipath effects can cause centimeter-scale shifts in carrier phase measurements. The carrier multipath is related to the location of the receiver, the variation of static multipath error is mainly affected by the satellite motion, showing the deviation characteristic, which is difficult to eliminate by using the existing differential technique or multipath error model. This paper defines the concept of carrier multipath peak-to-peak ratio in carrier correlator and uses it to measure the effect of multipath signal on carrier phase measurement. Considered the characteristics that multipath signals always lag behind direct signals, this paper presents a method of reference waveform design for on-time codes. The asymmetric cross-correlation function constructed by this method can suppress the cross-correlation of lag signals and improve the anti-carrier phase multipath capability. Through theoretical analysis and simulation, the proposed method of carrier phase multipath reduction can reduce the envelope area of carrier phase multipath error by about 49% when the gate width of the reference waveform is 1/4 chip, effectively increasing the receiver carrier multipath rejection.