天文导航中运动模糊星图恢复技术研究

Study on Motion Blur Image Restoration Technology in Celestial Navigation

天文导航是通过探测恒星并利用其在天体坐标中的已知位置信息,反解出探测平台姿态信息。无论是在可见光波段,还是在近红外波段对恒星进行探测,由于飞行器的快速运动和持续曝光时间的存在,在拍摄恒星图像时,容易造成星图的运动模糊,给后续的星图匹配和导航定位精度造成影响。针对星敏感器拍摄到的星图,在运动参数未知的情况下,利用Roberts边缘检测算子和自相关的方法分别确定出点扩散函数的方向和尺度参数,然后采用有约束的最小二乘滤波来复原恒星图像,取得了较好的效果,为天文导航后续的恒星位置确定及星图匹配奠定了基础。

Celestial navigation resolves the platform attitude information by detecting the stars and utilizing the given position of the stars from the celestial coordinates. When shooting the star image, the obtained images are likely to become motion blur, which affects the accuracy of subsequent star image matching and navigation position. This is due to the existence of rapid movement and the duration of exposure the aircraft, no matter the star is detected via the visible wavelengths or via the near infrared wavelengths. Under the condition of kinematic parameters of the mechanism, the Roberts＇s edge detectors and autocorrelation methods can be more useful by considering the star image obtained by the CCD star sensor for identifying and charactering the direction of point spread function and dimension parameter, respectively. Subsequently, a constrained least square filtering method is employed to restore the star image. Simulation results indicate that the constrained least square fil- tering method is effective in improving the star image accuracy. The findings of this investigation will serve as a base for the future study on star position determination and stellar map matching.