Vehicle Dynamic Continuous Gravimetry Technology Based on High-Precision 2-D LDV and GNSS

A existing strapdown inertial navigation system and global navigation satellite system (SINS/GNSS) integrated ground gravimetry method cannot receive GNSS information in sheltered places, such as tunnels and dense forests, which leads to the degradation of the system to pure inertial navigation and the rapid divergence of gravimetry error. To solve the problem, a novel method of gravimetry is proposed in this letter. The proposed method utilizes an SINS and a 2-D laser Doppler velocimeter (2D-LDV), which both developed by our unit, in conjunction with GNSS to achieve dynamic ground gravimetry. A high-precision laser Doppler velocimeter (LDV) is introduced to provide velocity information in a GNSS-denied environment. Also, high velocity and interference acceleration output accuracy of LDV also can further improve the gravimetry accuracy. We also discuss the methods of LDV data compensation and data fusion. Three-repeated-measuring-line experiment in mountainous areas shows that the SINS/LDV/GNSS integrated gravimetry system has an internal accuracy of 1.59 mGal with a spatial resolution of 1.1 km and 0.68 mGal with a spatial resolution of 1.7 km. Comparing this proposed method with the traditional SINS/GNSS and SINS/LDV gravimetry methods, it appeared that the gravimetry result using SINS/LDV/GNSS has the best internal accuracy. The feasibility of the SINS/LDV/GNSS integrated gravimetry system has been demonstrated by pertinent experiment.