Estimation of Error Model Parameters for a Rotating FOG-Based Measurement Unit of a Strapdown INS on a Vehicle

The paper studies the possibility of updating the parameters of error model of a rotating inertial measurement unit (IMU) with fiber-optic gyroscopes (FOG) in a strapdown inertial navigation system (SINS) under operating conditions. The IMU is placed in a two-axis gimbal for modulation rotation. The main focus is made on the estimation of scale factor errors of the FOG and accelerometers, non-orthogonality of their sensitive axes, and relative time delays (group delays) of inertial sensors during the IMU normal rotation according to the navigation solution of the INS in the observation mode of its operation. Also, the paper presents the description and results of estimation of so-called rhumb drifts of the IMU, which may occur due to the perturbing forces associated with the geographical axes or the axes of the system central device body. The research is based on the results of FOG-based INS simulation.