New calibration method for shipboard platform inertial navigation system

This paper presents ne w methods to calibrate a platform inertial navigation system (P INS) of a launch vehicle on a vessel. Due to environment disturbances such as waves, wind and vibrations, the signal-to-noise of the outputs of gyro and accelerometer is low. Therefore, the multi-position calibration methods which need to lock gimbals are not fit for calibrating gimbaled IMU on a moving base. When gimbals are not locked, the attitude information can be obtained by gimbal angle measurements. By rotating the gimbals continuously, gyro parameters can be calibrated separately using measurements of gimbal angles. Besides, a modified acceleration residual separation technique, which can compensate the nonlinear terms for accelerometer models, is developed to calibrate accelerometer parameters. Additionally, the gimbals rotation trajectory is designed to provide adequate observability for all parameters by a new methodology. The simulations are shown that the c alibration of gimbaled IMU can be carried out quickly with high precision by the presented methods and they are practical in dealing with environment disturbances.