Aiming at the issue of immobility of differential reference station in GPS carrier phase differential positioning,an algorithm of GPS precise relative positioning for moving base station was proposed.Firstly,geometry free measurements were structured based on Melbourne-Wubbena combination,which were then filtered by moving average filter.The double difference processing was adopted to further eliminate common error when dynamic user comes into the data link coverage of moving base station,and then the wide lane ambiguities were obtained.At this time,Kalman filter observation equation was established in combination with carrier phase double difference geometry based model.Then multipath error was modeled as first order Gauss-Markov random process and brought into state equation as augmented state parameters,thereby accurate estimate of float solution ofL1/L2ambiguity can be obtained.Lastly,the LAMBDA method was used to search the fixed ambiguity.Experiment results showed that centimeter level accuracy of relative positioning is obtained, which verifies the validity and applicability of the method.
