建立了地空导弹六自由度弹道方程 ,推导了弹体系弹目视线指向角误差 ,分析了不同雷达测量误差和导弹位置采用不同测量值的指向角误差协方差。结果表明 ,基于Kalman滤波的导弹位置融合可以减少捷联惯导初始对准误差引起的指向角误差 ,而直接采用惯导或雷达测量导弹位置 ,则初始对准误差的影响一直存在。 The ballistic equation of six degrees of freedom for surface-to-air missile was established, and the error of pointing angle error of the projectile bullet was deduced. The error of covariance of pointing angle with different measured values ​​and different measured values ​​was analyzed. The results show that the fusion of missile positions based on Kalman filter can reduce the error of pointing angle caused by the initial alignment error of SINS. However, the effect of initial alignment error always exists when the missile is directly measured by inertial navigation or radar.