摘要
“祝融号”火星车搭载的导航地形相机兼具路径规划与科学探测功能,为确保其三维测距和环境感知能力,在发射前已通过地面标定消除了相机固有畸变。然而,深空机动和着陆时所带来的外部冲击与长期暴露于火星极端环境等因素都有可能导致相机的光学结构发生改变,导致额外的相机固有畸变。为此,本研究提出了一种基于太阳能帆板上的标志点作为几何约束的就位标校方法,并应用于多个不同火星日的导航地形相机参数在轨就位标校。通过对比多个火星日的就位标校结果,发现导航地形相机的内方位参数的变化量较小,对导航地形相机图像的精度影响相对有限。通过结合火星的环境数据发现,相机焦距变化主要受火星表面温度波动影响,其变化规律与光学系统材料的线性热膨胀特性高度吻合。实验数据拟合显示,相机焦距与环境温度呈显著正相关,且拟合系数与材料已知的热膨胀系数一致。通过上述研究证实,即使在恶劣的火星环境条件下,“祝融号”的导航地形相机仍能保持长期稳定的工作性能。
This study analyzes the impact of the Martian environment on the internal orientation elements of the Zhurong Rover's Navigation and Terrain Camera(NaTeCam).Specifically,we investigate how external shocks experienced during deep-space maneuvers and landing,combined with prolonged exposure to Martian environment,influence the camera's optical structure and,consequently,its imaging performance.To address this objective,we implemented an in-situ calibration method utilizing reference points located on the Rover's solar panels as geometric constraints.Calibration was performed on NaTeCam image data from multiple Martian days(Sol-005,Sol-084,Sol-170,and Sol-247).The calibration process involved extracting feature points from the images,establishing geometric constraints using the known distances between reference points,and applying bundle adjustment to optimize the camera parameters.The initial parameters were obtained from pre-launch ground calibration,subsequent refinement was achieved using in-situ calibration derived solely from NaTeCam imagery.The in-situ calibration results show that the changes in the internal orientation elements of the NaTeCam are relatively small,indicating minimal impact on the camera's imaging accuracy.Notably,the focal length of the camera exhibits a significant positive correlation with the ambient temperature on Mars.The fitting results align well with the known linear thermal expansion coefficients of the camera's materials.In summary,this study confirms that the Zhurong Rover's NaTeCam can maintain stable performance in the challenging Martian environment.The proposed in-situ calibration method provides a valuable tool for ensuring the accuracy and reliability of stereo vision systems in deep-space exploration missions.
作者
田仁浩
李志斌
陈王丽
张旺军
陈朝鹏
张菁菁
吴文慧
任鑫
TIAN Renhao;LI Zhibin;CHEN Wangli;ZHANG Wangjun;CHEN Zhaopeng;ZHANG Jingjing;WU Wenhui;REN Xin(National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;University of Chinese Academy of Sciences,Beijing 100049,China;Beijing Institute of Spacecraft System Engineering,Beijing 100094,China)
出处
《第四纪研究》
北大核心
2025年第4期959-967,共9页
Quaternary Sciences
基金
国家重点研发计划项目(批准号:2022YFF0503204)资助。
关键词
祝融号火星车
导航地形相机
内方位元素
光束法平差
火星环境
Zhurong Rover
Terrain Camera(NaTeCam)
elements of interior orientation
bundle adjustment
Mars environment
