A Study Of GPS Differential Positioning Technology And Realization Method

The positioning theory of Differential GPS is introduced in the paper firstly, and then the working theory and method of position differential, pseudo-range differential, phase smoothing pseudo-range differential and carrier phase differential are analysed, and their positioning accuracy are compared. The system of constitute and working flow of multi-based local area differential and wide area differential are introduced briefly.It is mainly discussed from the spatial correlation and temporal correlation which influence accuracy of local area differential GPS, the error sources (troposphere delay, ionosphere delay, and orbit errors) are studied thoroughly. The method which can create error corrections terms of rover stations are developed by introducing the factor of weight, which is on the condition of different influences on rover stations made by base stations in local area network. Studied the message age of differential correction, the temporal correlation of positioning errors are described by using experimental data, and the relation of DGPS errors along with differential correction updating rate is presented.Several methods of calculating earth-center coordinate of base station are discussed, and then a new method weighted by DOP is proposed in the end. The method can improve positioning accuracy compared with single point positioning by test.