Application of PPP technology in non-datum or multi-datum survey area

When setting up the first-level control network without reference or multi-reference measurement area, the joint measurement of control points will consume a lot of energy, and the cumulative error is large. The precise singlepoint positioning (PPP) technology can effectively solve the problem. Based on a large number of IGS station data and measured data calculated by GrafNav software PPP, it is concluded that the plane error of PPP solution is less than 1 cm and the elevation error is less than 10 cm. At the same time, when the measurement period exceeds 4 hours, the variation of PPP solution error is small, and the longer the period, the better the stability of the solution accuracy. However, when the datum transformation is performed in the multireference measurement area, the epoch transformation has a great influence on the Y direction, and the accuracy of the reference transformation is greatly affected by the displacement variation value of the station.