Study on Algorithm and Communication Protocol of Differential GPS Positioning Based on Pseudorange

This paper presents a method of GPS differential positioning based on pseudorange. Both the generation and encoding of differential data based on pseudorange and differential data transmission protocol based on Internet are mainly discussed in the paper. An improved communication protocol is proposed which can decrease the transmission quantity without changing the differential positioning accuracy. The comparison between original data and coding data and the improved coding data are tested by instantiations. Experimental results show the modified coding method decrease the transmitted data amounts compared with the point positioning. When there are more than 9 satellites, the transmission quality acquired by this advanced communication protocol is only 70 percent of the RTCM protocol and the accuracy of the differential position is greatly improved.