An Improved Method Using SINS/PPP Method for Land Vehicle Gravimetry

Differential GNSS has been successfully applied in the SINS/GNSS vehicle gravity measurement method over the past few decades. However, GNSS error source has the spatio-temporal correlation in the differential mode. The navigation resource utilization efficiency is degraded due to the limitation of the baseline distance and the satellite common view. Using only one satellite receiver with high precision satellite orbit parameters and clock parameters, establishing navigation error models and parameter estimation methods, and obtaining high-precision receiver dynamic positioning, Precise Point Positioning (PPP) is a promising non-differential mode GNSS technique. The advantages of PPP are that it is simple to operate, low in cost, and not limited by the requirements for establishing a base station. This paper presents an SINS/PPP method for land vehicle gravimetry. Based on the strapdown gravimeter SGA-WZ02 developed by the National University of Defense Technology (NUDT), a land vehicle gravimetry test was carried out on a road about 36 kilometres long. The test consists of four measuring lines back and forth in the north-south direction with an average speed of 40km/h. Using this method, the internal accuracy of four repeated lines is 0.52mGal/0.9km. Compared with the results obtained by traditional SINS/GNSS method, the internal accuracy is 0.51mGal/0.9km, which shows that the accuracy calculated by SINS/PPP method is comparable to the results calculated by SINS/DGNSS method. Practical gravimetry results indicate that the proposed SINS/PPP method in this paper can meet the requirements of vehicle gravimetry under ideal GNSS observation conditions, and the feasibility of PPP technology for vehicle gravimetry is verified. Finally, some discussions and suggestions about the applicability of the method and its further improvement are put forward.