Topographic Reconstruction of the "Tianwen-1" Landing Area on the Mars Using High Resolution Imaging Camera Images

High-resolution optical cameras have always been important scientific payloads in Mars exploration missions, and the Mars topographic data produced by their detection data can provide support for scientific research on Mars geomorphology and geological structure evolution. As of December 2021, there are still relatively few high-resolution image data at the submeter level on the Martian surface, with about 2.6% global coverage and even more limited stereo coverage (just about 0.4%). At the same time, there are still some difficulties in data acquisition and terrain reconstruction processing methods for high-resolution Mars images that need to be solved. This article described how we designed the in-orbit stereo imaging strategy based on the characteristics of the high-resolution imaging camera (HiRIC) of China's first Mars exploration mission (Tianwen-1), studied the technical solutions for HiRIC stereo image photogrammetry processing, and produced a topographic dataset for the "Tianwen-1" landing area, including a digital orthophoto map (DOM) with a ground sample distance (GSD) of 0.7 and 3.5 m and a digital elevation model (DEM) with a GSD of 3.5 m. Precision analysis results show that these topographic data have good consistency in planar position and elevation compared with the existing Mars terrain data and have advantages in spatial resolution and terrain detail expression, which will be widely used in the geological background study of the "Tianwen-1" landing area, as well as landing site positioning, Martian surface remote operation planning, and other Mars scientific research and engineering tasks.