解体速度增量计算方法研究

解体速度增量是解体事件强度的重要指征, 它决定了解体产生碎片的轨道分布. 通过分析解体速度增量可以推断解体强度, 确定解体形式. 解体速度增量有两种计算方法, 即轨道位置演化法和轨道面相交法. 轨道位置演化法是根据解体前后轨道速度的变化直接得到解体速度增量; 而轨道面相交法是利用母体以及解体碎片的球面三角几何关系, 根据解体碎片的倾角和升交点赤经变化, 以及母体轨道的倾角和近地点辐角, 计算解体时刻母体轨道的真近点角, 从而得到解体的时间和速度增量. 相比来说, 轨道位置演化法适用于数据精度高, 解体高度高情况下的解体事件分析, 而轨道面相交法适用于解体高度低, 碎片数据公布时间较为滞后的解体事件分析. 根据解体速度增量的计算方法及其原理, 对两种方法的适用性进行了比较和讨论, 并选取已经发生的三次解体事件, 利用美国公布的TLE数据, 针对具体情况选择计算方法, 给出了三次解体事件发生的时间和解体碎片在空间三个方向上的速度增量. 

Study on Fragmentation Velocity Increments

Fragmentation velocity increments were an important character for breakup events intensity which decided the fragmentation debris orbit distribution and breakup nature. In this paper two means were given for the fragmentation velocity increments. One is orbit position propagation means, the other is orbit plane intersection means which was introduced in details. Orbit position propagation means is that velocity increments are computed by orbit velocity changes before and after the breakup; Orbit plane intersection means is that the velocity increments are computed with breakup spherical triangle for the parent and debris, the changes of breakup debris inclination and right ascension of ascending node, and the parent orbit's inclination and argument of perigee at the breakup epoch. The breakup epoch and velocity increment is then obtained. Compared with the two means, orbit position propagation means is suitable to fragmentation events with high quality data and high fragmentation altitude; orbit plane intersection means is suitable even if the fragmentation altitude is low and the orbit data is lagged more. This paper introduced the means and principle of computing breakup velocity increments, compared and discussed the applicability of the two means in detail. Based on the two means, fragmentation epoch and three velocity increments components in space were given for three past breakup events with two-line element data.