An Online Error Estimation Method Based on Two Rotational Inertial Navigation Systems

Rotation modulation technology significantly enhances the navigation accuracy of inertial navigation systems (INS), thereby facilitating the widespread application of rotational inertial navigation systems (RINS). In marine or airborne applications, it is common to install two or more RINS units on the same carrier. By employing information fusion techniques, the navigation performance can be significantly enhanced. This paper proposes an online error estimation method for two RINSs. This method is based on the information fusion of two systems. It employs two RINSs with rotation strategies around different axes and utilizes rotation modulation technology to improve the observability of inertial sensor errors. Through Kalman filtering, the online optimal estimation of the gyro drift, accelerometer bias, scale factors and installation misalignment angles of two systems can be achieved. The simulation and experimental results demonstrate the effectiveness of the proposed method in performing online estimation of inertial sensors errors for the two RINSs. Specifically, the estimation accuracy reaches about 0.001°/h for gyroscope drift, about 2μg for accelerometer bias, about 2″for misalignment angles, and about 2 ppm for scale factors in both static and dynamic conditions. Through error compensation and information fusion, the navigation accuracy has increased by 62% in a static state and by 57% in a dynamic condition, thereby validating the efficacy of the proposed methodology.