小天体高速撞击器视线制导律设计

Design of Line-of-sight Guide law for Small Body High Speed Impactors

针对小天体高速撞击器设计了一种视线制导律。为了解决轨道修正机动时机选取问题,本文引入B平面点位误差椭圆描述预测撞击点的置信度,通过控制撞击点落入指定的误差椭圆概率区域内,将轨道修正机动时刻选取问题,转化为对发动机开关曲线的设计。该制导律利用当前位置、速度信息构建视线旋转角速度与距离变化率,驱动发动机开关抑制视线的旋转角速率,使其最终撞击到目标点上。严格的蒙特卡罗仿真表明,该制导律在节省燃料的同时,可以使撞击精度比预测制导方法提高100米以上,达到250米以内。

A Line-of-Sight（LOS） guide law is designed for small body high speed impactors. Error ellipse on thc B-plane is utilized to describe confidence level of the predictive intercept point for solving the problem of the trajectory correction maneuvers execution selection. Then, the trajectory correction maneuvers execution timing is translated into design of switching curve through guiding the intercept point into appointed error ellipse. The rotation velocity and distance variety ratio are constructed by using impactors＇ position and velocity and the engine is driven to enable impactors to reach the aim point by restraining Line-of-Sight rate. The results of strict Monte Carlo simulations show that this guide law improves on predictive guide law in the impact precision upward of 100 meter, and maximal impact error is less than 250 meter, simultaneously economizing fuel.