An All-Parameter Calibration for 6-Axis Skewed IMU

The inertial navigation system (INS) is widely used in spacecraft, missiles, and airplanes for its full autonomy and complete information. Skewed inertial measurement unit (IMU) is a typical device for INS. This IMU is of great significance for key projects such as manned spacecraft or heavy-lift rockets. Calibration of the IMU parameters has always been the key technology for INS. However, the calibration for skewed IMU is difficult to conduct for the skewed placement of the sensors and the complicated model. An all-parameter calibration for six-axis skewed IMU is proposed in this article. The error model is established. The measurement equations for Kalman filter are deduced. The calculation can be accomplished in two steps: The calibration for three gyros+ three accelerometers and the parameter compensation and iteration calculation. Simulations and experiments results indicate that: The complexity of calibration data and procedure is the same level as that of traditional IMU; all the parameters can be precisely estimated with the designed 12 positions sequence.