An Improved Rotational Modulation Scheme for Tri-Axis Rotational Inertial Navigation System (RINS) with Fiber Optic Gyro (FOG)

An optimized scheme can improve the navigation accuracy of RINS without changing inertial devices. In multi-position stop scheme, IMU remains stationary for most time, which makes motor control easier. However, installation errors and scale factor FOG cause platform misalignment after a certain angle rotation around horizontal axis, resulting in velocity error. Continuous suppress time-varying better, is particular importance FOG, but it also increase sawtooth error output, direction cannot be offset. To integrate advantages both schemes, we propose an improved rotational modulation tri-axis RINS. this inner gimbal rotates two-position four-order manner, while middle outer gimbals rotate continuously order forward-reverse-reverse-forward. Simulation test results demonstrate that effectively by 50% 25% compared with continuous azimuth axis 16-position same devices, great FOG.