说明：  雷达对导弹进行测距，导弹受气流扰动同时雷达观测存在观测误差，通过卡尔曼滤波对导弹距离进行估计
(Radar is used to measure the range of missile. The missile is disturbed by airflow and there is observation error in radar observation. Kalman filter is used to estimate the range of missile.)