碰撞风险评估标准适用性分析

A Research on Adaptability of Collision Criterion

随着空间碎片数量的不断增加,空间目标碰撞预警技术已经受到人们越来越多的关注.早期普遍使用几何区域(BOX)判定法对空间目标的碰撞风险进行评估,但它是一种比较保守的方法,工程实用性低;90年代后开始广泛地研究和采用碰撞概率判定法,这种方法综合考虑空间目标交会时刻的多个参数,但是由于其数学模型对轨道误差数据的依赖程度很高,所以在某些情况下会导致预警结果不准确.通过仿真的方法,模拟两条确定交会的标准精密轨道,由程序生成随机误差加入到标准轨道生成有误差的轨道,计算最接近距离和碰撞概率,并分析二者之间的关系.结果表明,当轨道预报精度较差时,碰撞概率判定法可能会失效,需要结合几何区域判定法进行综合判定,以避免碰撞预警过程中的"误判"和"漏判".

With the rising number of space debris, people pay more and more attention to the space debris collision avoidance system （SDCAS）. In the early 1990s, the BOX method is commonly used as a collision criterion to decide whether the avoiding maneuver is necessary for spacecraft. But this method has low practicability, so the method of collision probability is developed. In this way, both the relative distance and the geometrical parameters at the closest approach time are taken into consideration. However, the mathematical model of this collision criterion depends highly on the covariance, so it may lead to some inaccurate results. In this paper, the rendezvous of two orbits are simulated, and the errors are considered, then the relative distance at the closest approach time and the collision probability are calculated. The results indicate that the covariance plays an indispensable role in measuring the risk of collision. When the precision of orbit prediction is not very good, it is better to combine the BOX method and the collision probability method in the SDCAS.