A Three-Point Calibration Method for DVL Errors in Underwater Navigation

The strapdown inertial navigation system (SINS)/Doppler velocity log (DVL) integrated navigation is now widely applied by autonomous underwater vehicles (AUVs). In SINS/DVL integrated navigation, the DVL is applied to restrain the error accumulation of SINS. To enhance the navigation accuracy, it is essential to calibrate the DVL errors. In this article, a three-point calibration method is proposed. Compared with most existing researches, it removes the requirements for continuous external reference from global navigation satellite systems (GNSSs), thus avoiding the AUV sailing on the water surface in the whole calibration process. Based on a novel technical route, it can calibrate the constant bias, scale factor error, and installation error of DVL at once, with only applying the GNSS positions at the start point and two upper floating points of the AUV. Most importantly, from the perspective of observability analysis, the calibration trajectory design is in-depth studied and two guidelines are summarized, thus providing theoretical supports for the three-point calibration. The effectiveness of the proposed method is verified by Monte Carlo simulations and semiphysical experiments. The comparative results indicate that the proposed method can effectively calibrate the DVL errors and further improve the accuracy of SINS/DVL integrated navigation.