Research Of Relative Position System Based On GPS Multiple Reference Stations Difference

With the rapid development of the economy and modern technology, GPS high precision positioning has became one of the important applications in high precision intelligent robot navigation, ground mapping and disasters monitoring. Meanwhile, in people’s production, life and scientific research, the research and application of GPS high accuracy position system have gained more and more attention. At present, GPS carrier phase difference and pseudo-range difference are positioning methods has high location accuracy,among them, GPS carrier phase difference is become popular by its high positioning accuracy,all weather and removable. But, the current GPS carrier phase differential positioning system almost need to get the accurate 3D coordinate of the base station in the center of the earth coordinate system in advance. But it is usually difficult to quickly obtain the precise coordinates of the base station, resulting in a long time of the initialization, so that its application has been greatly limited. In order to meet the application demand of the precision agriculture and intelligent UAV that need a rapid and accuracy location, the paper gives a new relative position system design idea according to GPS multiple reference stations difference base on the study of research on single base station difference positioning system. The software and hardware of the system are developed and implemented. Meanwhile, the corresponding experiments are carried out to verify the results, show that the positioning system not only improve the level of positioning precision of the GPS differential positioning,but also because of without the base station precise coordinates, make it have fast positioning,convenient application and so on, can satisfy the demands of high precision positioning in some areas.Firstly, on the basis of the in-depth study of the GPS positioning and navigation system basic principle and data processing theory, gives a new relative position system design scheme according to GPS multiple reference stations difference, At the same time the traditional carrier phase double difference model has been improved. Meanwhile, in terms of the data processing, the error of random error, multipath effect and cycle slip error are analyzed and processed, and the experiment of detection and repair of the cycle slip is carried out.Secondly, the hardware design of the system, including miniaturized GPS base station and mobile station, the GPS receiver and antenna selection, GPS data pre-treatment module and the positioning calculation module design has been set up. At the same time in order to ensure effective differential data transmission, the data link has been designed, and the performance is verified by experiment.Finally, based on the system hardware platform, data link and the double difference modified model, the software design of each function module is designed according to the basic principle of software design, and the relative location of mobile station location was carried out to calculate real-time static experiment.