中文摘要：

针对目前通常采用计算碰撞概率来进行空间目标碰撞预警的方法,为提高其评判标准的精度以达到提高航天器精准预警的目的,分析了目前空间目标碰撞概率阖值确定过程的总体框架.对阈值确定过程中所涉及的误差协方差矩阵确定方法、碰撞概率计算以及碎片通量计算方法进行了研究。以国际空间站（ISS）为例,通过计算其所在空间的碎片通量,分析其轨道受空间环境的影响情况,并与早期结果进行比较,得出其以往的碰撞概率阈值可能被高估的结论.

英文摘要：

The method of collision probability is usually used to realize the work of collision assess- ment and warning of space objects, thus improving accuracy of collision assessment and warning is very important. The collision probability criterion is collision probability threshold. By investigating and analyzing the related bibliography from both domestic and international researchers, a compre- hensive description on determination of collision probability threshold of space objects is presented. The determination of covariance matrix, the calculation of collision probability and the flux calculation of debris are introduced in detail. Taking International Space Station （ISS） for instance, of which, the debris flux was calculated and the incidence from space environment was analyzed. The conclusion that collision probability threshold of ISS may be overrated is reached by comparing with previous results.