再入体气动参数辨识

Aerodynamic Parameter Identification of a Reentry Body

采用极大似然辨识方法对再入体的气动力和气动力矩系数及小不对称量进行辨识，用辨识的气动参数重构再入体的飞行弹道，用以验证气动参数辨识的准度。某再入体飞行速度接近第１宇宙速度，再入体绕体轴纵轴自旋，进入大气层后，由于严重的烧蚀使气动力和气动力矩产生了小不对称量，而再入体又是不可控的，给气动参数辨识带来很大困难。采用解耦的方法获得了较为精确的小不对称气动参数估值。还介绍了某再入体气动参数辨识过程中一些问题的处理技巧和经验。

The aerodynamic force, moment coefficient and small asymmetrical amount of a reentry body are identified with maximum likelihood method in the paper.The present identification accuracy of these aerodynamic parameters can be tested through the reentry body flying trace reconstructed by its identified aerodynamic parameters. When the reentry body,rotating axially,reenters the air with a approximate first cosmic speed,there is small asymmetrical amount of aerodynamic force caused by severe ablation. It is difficult to identify the aerodynamic parameters as the reentry body is out of control during reentering the air. In this paper,an accurate estimation of small asymmetrical aerodynamic force is gained with the decoupling method. Some techniques and experiences in dealing with the identificantion problem are also introduced.