Application of Single Point Calibration Algorithm of Optical Velocimeter in SINS/VEL Vehicle Gravimetry

Aiming at the requirement of SINS/VEL vehicle gravimetry for quick and accurate calibration of velocimeter, this paper proposes a single point calibration algorithm of velocimeter which could calculate all velocimeter calibration parameters only by a high-precision external 3-D reference coordinate point. It helps SINS/VEL vehicle gravimetry system to get rid of the continuous dependence on DGNSS. Meanwhile, there is no need to store raw data in calibration stage, which means offline processing is not required and SINS/VEL vehicle gravimetry could be carried out directly without midway stop. At the end, a SINS/VEL vehicle gravimetry experiment carried out in Changsha verifies the effectiveness and the correctness of the proposed method. The test results show that after adopting the proposed single point calibration algorithm, the horizontal position error of SINS/VEL vehicle gravimetry system is less than 104 m, while the vertical position error is less than 5.2 m. The total repeat line internal accord accuracy of SINS/VEL vehicle gravimetry could reach 1.39 mGal with a spatial resolution of 1.7 km, which is comparable to that of SINS/GNSS vehicle gravimetry carried out in the same region under good satellite observation conditions. This proves that the proposed algorithm could effectively assist to realize SINS/VEL dynamic vehicle gravimetry under the satellite forbidden circumstance. It improves the environmental adaptability of vehicle gravimetry and expands to wider applications. What’s more, no midway stop of this algorithm may have the potential to help to realize SINS/VEL vehicle real-time gravity measurement.