A Novel Calibration Method Between Two Marine Rotational Inertial Navigation Systems Based On State Constraint Kalman Filter

A novel calibration method between two marine rotational inertial navigation systems (RINSs) is proposed in this paper. The problem of RINS calibration without accurate external reference information in outfield can be solved using the proposed method. The RINS1 is a dual-axis rotational modulation inertial navigation system in normal operation mode. The RINS2 is an inertial navigation system with a dual-axis turntable to be calibrated. The 45-D Kalman filter is established with the state constraint observation of the relative velocity and position between the two systems, in which the RINS1 still works independently. All error parameters of the RINS2 can be calibrated without external reference information. The validity of the algorithm is proved by the Monte Carlo simulation, the real system experiment, and the calibration experiments at different times. The result shows that the algorithm achieves the estimation of all error parameters, with the gyro scale factor error less than 0.4 ppm (1σ), the accelerometer scale factor error less than 0.8 ppm (1σ), and the installation error less than 1.6" (1σ). The calibration accuracy of RINS2 is not affected by the absolute position error of RINS1 and the error parameters can be calibrated autonomously in motion.