A Robust Method for Alignment Calibration of an Inertial Measurement Unit (IMU) and Doppler Sensors
W-L. LI, L. Yang, L-D. Zhang, M-J. Chen and K-H. Tang
Alignment calibration of an inertial measurement unit (IMU) and Doppler sensors is a key factor that limits the accuracy of inertial navigation system (INS)/Doppler velocity log (DVL) integrated navigation. The commonly used methods in alignment calibration that need continuous externally-aided information are inconvenient for underwater vehicle applications. In this paper, we propose a simple and easy alignment calibration method, which only needs one additional position besides the initial position. Nevertheless, the DVL-aided INS initial alignment is still a challenge, as it impacts the accuracy of the proposed calibration method. Therefore, an attitude backtracking technique that can improve the calibration robustness is proposed. Experimental results show that the proposed method is able to eliminate the effects of the INS initial alignment and hence yield reliable calibration results.
Keywords: Inertial measurement unit (IMU), Doppler sensor, inertial navigation system (INS), Doppler velocity log (DVL), laser gyroscope, underwater, alignment calibration, initial alignment, backtracking, robustness