中文摘要：

随着火星探测任务需求的提升,着陆器在火星表面着陆精度的要求越来越高.着陆器开伞点分布是影响着陆精度的重要因素.文章围绕火星大气进入过程,简要介绍了着陆器运动学方程,并给出相应的数学模型.针对进入点（接触大气层）存在的初始状态误差,借助Monte Carlo法进行了着陆器开伞点分布情况分析.通过1 000次重复仿真试验得出结论,着陆器开伞点的纵向误差在20～40 km,横向误差在5～10 km.最后,针对提高开伞点精度,提出两点建议并简要介绍了相关制导算法。

英文摘要：

With the development of the Mars explore mission,the problem of precise landing is now considered to be an essential challenge.For a Mars landing mission,the initial condition errors would result in the deviation of parachute deployment,so the landing point errors would be larger.The Mars atmospheric entry phase was introduced,and the dynamic equation of the vehicle and the corresponding mathematic models were proposed.A 1 000-run Monte Carlo study was performed to analyze the parachute deployment deviation under the initial condition errors.The study shows that the down range error is 20～40 km,and the cross range error is 5 ～ 10 km.Some suggestions were given for the parachute deployment precision,and some entry guidance algorithms were also introduced.