说明：  用一观测器从t 1秒开始对一个运动目标的距离进行连续地跟踪测量,假设观测的间隔为一秒钟,雷达到运动目标之间的距离为S(t)
(A continuous tracking measurement of the distance of a moving target is carried out with an observer starting from t 1 second, assuming that the interval between observations is one second and the distance between the moving targets reached by the thunder is S (t))