A Novel Fault Detection and Isolation Technology for Redundant Inertial Measurement Unit

The fault detection and isolation (FDI) accuracy directly affects the redundant inertial measurement unit (RIMU) working state. The previous methods are difficult to apply to the four-axis system because they do not have enough information to allow fault isolation. Therefore, in this article, an extended RIMU system is proposed to implement fault location in a four-axis system. The extended system consists of three additional accelerometers and a four-axis RIMU. The specific force information in the gyro-free strapdown inertial navigation system (GFSINS) is used to obtain reference angular velocity information. Then, based on the extended system, a fault detection procedure is designed to achieve faulty gyro isolation and system reconfiguration. Simulation results show that the extended system can effectively isolate gyroscope failures in a four-axis RIMU system. Compared to the non-redundant three-axis system, the extended system is $1.75\times $ more reliable and has 37% better average navigation accuracy.