An inertial device biases on-line monitoring method in the applications of two rotational inertial navigation systems redundant configuration

Rotation modulation technology can enhance the autonomous navigation accuracy of inertial navigation system significantly, which has contributed to the wide applications of rotational inertial navigation system (RINS). To ensure the reliability and safety of high-precision autonomous navigation for the long endurance navigation in vehicle or marine applications, two or more RINSs are usually equipped. In this condition, the RINSs fault detection and isolation can be realized by comparing the differences of navigation information from different RINSs. In this paper, an on-line monitoring method for inertial device biases in the applications of two RINSs redundant configuration is proposed. The method takes advantages that the rotation modulation technology could improve the observable degrees of inertial device biases to achieve on-line optimal estimation of the gyro drifts and accelerometer biases for all the six gyros and accelerometers of the two RINSs. Two RINSs redundant configuration was presented and the inertial device biases estimation models were deduced. Based on the system model, simulations and experiments were both conducted. Simulation and experimental results showed that the proposed method could detect and isolate the faulty inertial devices of two RINSs effectively in autonomous navigation. Furthermore, gyro drifts monitoring accuracy could be better than 0.001°/h and accelerometer biases monitoring accuracy could be better than 1 μg in cases where the random constant gyro drifts are 0.02°/h (1σ) and random constant accelerometer biases are 50 μg (1σ), which demonstrates the effectiveness of the proposed inertial device biases on-line monitoring method.