基于CCD星图的空间目标精确光学定位方法研究

Methods Accurately Locating Optical Positions of Space Object Based on CCD Stellar Images

通过光学定位方法来确定空间目标的轨道是实现空间目标监测的重要手段之一。介绍一套小型的空间目标光学定位系统,针对该系统获取的CCD星图,提出Top-hat变换和中值滤波相结合的算法去除星图噪声,并提出基于梯度Hough变换的算法完成对CCD星图星点和轨迹的同时精确定位,最后利用星角距的旋转不变性和球面几何原理,实现对空间目标的精确定位。对分辨率为752×580的CCD实拍星图的应用研究结果表明,星图去噪算法和星点、轨迹同时精确定位算法是有效的,且空间目标的定位精度也可达到角秒量级。

Optical measurements of positions of space objects are important means to derive the orbits of moving space objects for surveillance.We introduce a miniature system of locating space objects optically,which is based on recording CCD images.We apply denoising methods of Top-hat transformation and median filter to a CCD image recorded for an object.We further use a new algorithm based on the Grads Hough Transformation for simultaneously and accurately locating the positions of background stars the track of the object.Finally,we are able to accuretly derive the position of the space object based on invariance of angular separations between stars and formulas of spherical geometry.The results of applying the system and methods to a satellite with size of the CCD image 752 × 580 show that the methods of image denoising and the algorithm of locating stellar positions and object track are effective,and the accuracy of locating the position of a moving space object can be of a few arcseconds.