Abstract:In order to improve the precision of strapdown inertial navigation system(SINS), a Kalman filter model is established to estimate the gyro constant drift and the bias of accelerometer. Firstly, the error characters of the SINS in the process of forward and reverse rotation are analyzed. Then, a Kalman filter model is established by setting the attitude errors and velocity errors as the state variable, the difference of attitude errors and the value of velocity errors in the same position as observed variables.The observability analysis shows that the model is observable. In the simulation experiment, when all three gyro drifts of the SINS are 0.1 (°)/h and accelerometer biases are 9.78×10-3 m/s2, the gyro drift estimation precision is better than 0.01 (°)/h,and the error of accelerometer bias estimation in the horizontal direction is less than 0.4×10-3 m/s2.The result shows that the scheme is feasible.