Improving Land Vehicle Gravimetry Using a New SINS/GNSS/VEL Method

Abstract GNSS plays a key role in land vehicle gravimetry. However, GNSS is unstable due to the influence of the observation environment, which adversely affects the gravimetry accuracy. The velometer can get rid of the restrictions on the use of GNSS by land vehicle gravimetry. In this paper, a SINS/GNSS/VEL method is proposed. This method uses both centralized filtering and federated filtering methods to process the gravity data. Based on the SGA-WZ02 strapdown gravimeter developed by the National University of Defense Technology (NUDT), the vehicle gravimetry test was carried out on a road of approximately 37 kilometers in east Changsha. The test consists of 4 lines in the south-north direction with an average speed of 40 km/h. Compared with traditional SINS/GNSS method, the accuracy of repeated lines using the centralized filtering method improves from 1.58mGal to 1.37mGal, and the external accuracy improves from 2.31mGal to 2.19mGal with a resolution of 2 km. Using federal filtering method, the internal accuracy is 1.36mGal and the external accuracy is 2.22mGal. It indicates that these two methods proposed could both improve the accuracy of gravimetry compared with the traditional SINS/GNSS method. Meanwhile, with adding the external sensor observation, these methods can improve the stability of gravimetry especially for practical survey operations that will save cost and improve efficiency. Finally, several discussions are proposed on the applicability and further improvement of the method.