深空光通信中的图像信标捕获技术

为实现深空光通信链路建立过程中精确的对准,提出了一种深空光通信系统扩展信标的捕获方案。该方案以可视地球图像作为信标,在航天器上存储一幅信标图像作为参考图像,采用天线扫描的方式在各点对所瞄准的区域成像,利用像素扫描的方式,使参考图像和实际探测图像进行相关,在天线扫描完成以后,找出相关性最大的位置,即可认为在该点捕获到地球图像。在计算两图像相关系数的过程中,由于傅里叶梅林变换幅度谱具有伸缩及旋转不变性,因此利用傅里叶梅林变换即可消除两图像相关系数因为旋转和伸缩的影响。利用蒙特卡罗方法随机产生1000个视场,仿真结果表明,3σ内正确捕获到信标图像的概率为99.6%,表明这是一种可行的方法。

Image Beacon Acquisition for Deep Space Optical Communication

In order to achieve the accurate pointing during the course of deep space optical communication link setting up, a scheme is proposed to acquire the extendbeacon for deep space optical communication system, which uses visual earth image as beacon, and stores a beacon image in aircraft as reference image. CCD is adopted to image the pointing area based on antenna scan pattern. The correlation coefficient of the detected image and reference image is calculated based on pixel scan pattern. The location where the correlation coefficient is maximum is found out after antenna scan, which can be regard as the location where the beacon image is acquired. Because of the rotation and scale invariance of FourierMellin transform, the effect from rotation and scale of image will be eliminated based on FourierMellin transform. 1000 random fields of view are created using MonteCarlo method, to simulate the progress of acquisition, and the result shows that the successful acquisition probability is 99.6% within 3σ, validating its feasibility.