重力辅助阻尼捷联惯性导航系统

Damping strapdown inertial navigation system aided by gravity

在基于扩展卡尔曼滤波的重力辅助捷联惯性导航系统中,滤波器的状态方程为捷联惯性导航系统的误差方程。舒勒周期振荡误差存在于无阻尼捷联惯性导航系统中,同时也存在于滤波器的状态方程之中,从而对滤波器的估计精度造成一定影响。为了消除滤波器状态方程中的舒勒周期振荡误差,设计捷联惯性导航系统工作于外水平阻尼状态,建立阻尼状态下的扩展卡尔曼滤波器状态方程以及重力异常观测方程。试验表明重力辅助阻尼捷联惯性导航系统96 h的定位精度优于0.5 nmile。

In the gravity-aided strapdown inertial navigation system （SINS） with an extended Kalman filter, the state equation of the filter is the error equation of SINS. However, the oscillation errors with Schuler period exist in the undamped SINS and the state equation of the filter. This leads to the degradation of the estimated accuracy of the filter. To remove oscillation errors with Schuler period in the state equation of the filter, we made the SINS work in the external level damping state. Then we established the state equation of the extended Kalman filter in the case of the damping state and the measurement equation under gravity anomalies. The 96 h simulation results demonstrate that the accuracy of the gravity-aided damping SINS system is less than 0.5 nmile using the proposed method.