A Single-axis Rotation Modulation Initial Alignment Algorithm Based on Inner Lever Arm Effect Compensation in Accelerometers

摘要

The initial alignment technology is one of the key technologies of INS(Inertial Navigation System). When applying traditional Kalman-based initial alignment algorithm to a continuous-rotation INS, it is found that the filter converges very slowly and the errors are big, which is mainly caused by the installation error of the accelerometers with respect to the rotational center of the IMU. To solve the problem, the inner lever arm effect of the accelerometers is taken in to account and an improved alignment algorithm is proposed based on an extended SINS error model. The error caused by the inner lever arm effect of the accelerometers under high speed rotation is estimated and compensated, and a single-axis rotation scheme about the yaw axis is designed, taking into account the rotation speed and modulation time as parameters. It is experimentally verified that the improved algorithm has higher accuracy than traditional algorithm.