一种小行星探测陆标导航方法

A Landmark Navigation Method for Asteroid Exploration

针对小行星探测下降着陆段精确相对导航问题,提出了一种基于Stereophotoclinometry(SPC)陆标的相对导航方法.该方法先采用SPC光照模型渲染陆标的预测图像,再利用双线性插值从观测图像中生成陆标的提取图像.通过组合相关匹配实现预测图像与提取图像的高精度匹配,得到陆标中心点对应观测图像位置,即可利用N点透视(PNP)算法进行相机位姿估计.仿真结果表明,该方法在初始相机位姿偏差较大时也能达到亚像素的图像位置确定精度,并且具有较好的实时性.

To implement high-precision relative navigation during the descent and landing phase of asteroid exploration,a landmark-based relative navigation method is proposed.The predicted image of the landmark map(L-map/maplet)is first rendered by the stereophotoclinometry(SPC)illumination model,and the extracted image of the maplet is then generated from the observed image using bilinear interpolation.The combined correlation matching method is adopted to perform exact matching between the predicted image and the extracted image,and obtain the observed image location of the landmark center accurately.Therefore,the camera pose is estimated by the perspective-n-point(PNP)algorithm.The simulation results show that this method can achieve sub-pixel accuracy even when the initial camera pose deviation is slightly large,and it has good real-time performance.