基于非线性滤波的捷联惯导系统罗经法对准改进算法

Improved compass alignment algorithm for strapdown inertial navigation system based on nonlinear filtering

为提高捷联惯导系统初始对准的快速性和精确性,根据传统的平台惯导系统罗经法对准原理,提出包括水平对准和方位对准的捷联式罗经对准算法.给出了导航坐标系下加速度和角速率的修正值,经过姿态矩阵的转换对载体坐标系下的惯性测量组件输出值进行修正补偿.对不同初始姿态角误差和不同初始航向角的仿真表明,初始航向角的改变对系统影响较大,特别在大方位失准角情况下.采用UKF算法对非线性模型滤波的仿真结果显示,最大航向角误差从15′降至6′,证明将罗经法和UKF滤波方法相结合进行捷联系统初始对准是可行有效的.

A strapdown compass alignment algorithm including horizontal alignment and azimuth alignment was developed to enhance the rapidity and accuracy of initial alignment of strap down inertial navigation system （SINS）based on the principle of compass alignment for platform inertial navigation system. Cor rections of acceleration and angular rate under navigation coordi nate system were given, and then the output values of inertial measurement units were compensated under carrier body coordi nate system by using attitude matrix transformation. Simula tions under different initial attitude errors and heading angles show that initial heading angles have obvious impact on initial alignment especially under large azimuth misalignment angles. The unscented Kalman filter （UKF）algorithm was used to filter the nonlinear model. Simulation result also shows that the larg est heading error decreases from 15＇ to 6＇, which verifies that the method of combining compass alignment with UKF filtering in SINS initial alignment is feasible and effective.