In order to improve the performance of multipath mitigation in tracking Galileo signals, a new multipath mitigation method named early-late strobe correlator （ELSC） is proposed. By applying the strobe correlator used widely in global positioning system （GPS） scenarios to Galileo E1 signals, it can be found that the strobe correlator has an undesirable level of performance when the delay of multipath signals is about 0. 5 chip. Combining several strobe correlators, the ELSC can effectively mitigate the multipath effect especially for the multipath signals with the 0. 5 chip delay. The multipath error envelopes between the strobe correlator and the ELSC are compared for Galileo E1 signals. The simulation results indicate that the ELSC performs excellently on multipath mitigation, and can be applied in both Galileo scenarios and GPS scenarios.
A method for integer ambiguity resolution in the global positioning system （GPS） multi-reference station network real time kinematic （RTK） is proposed. First, the barycenter of the triangle of reference stations for ambiguity resolution is taken as a reference point. The satellite which has the largest elevation angle with the reference point is selected as a reference satellite. The parameters for constructing the weight matrix of carrier phase observation and the criteria for checking the correctness of integer ambiguity resolution of a network are obtained. Then, the wide ambiguity is calculated by a linear combination method of dualband observation. And the LI ambiguity is obtained by a nonionosphere combination method. The Kalman filter is introduced to refine the floating-point solution of ambiguity and estimate the real-time tropospheric delay. Finally, the cofactor matrix of ambiguity is de-correlated by Z-transformation to reduce the searching space of the integer ambiguity solution and improve the efficiency of the least-squares ambiguity decorrelation adjustment （LAMBDA） algorithm. The experimental results show that this method can reliably obtain the integer ambiguity solution among multi-reference stations with 40 epochs.
