Rover Attitude and Camera Parameter: Rock Measurements on Mars Surface Based on Rover Attitude and Camera Parameter for Tianwen-1 Mission

Rocks, prominent features on the surface of Mars, are a primary focus of Mars exploration missions. The accuracy of recognizing rock information, including size and position, deeply affects the path planning for rovers on Mars and the geological exploration of Mars. In this paper, we present a rock measurement method for the Mars surface based on a Rover Attitude and Camera Parameter (RACP). We analyze the imaging process of the Navigation and Terrain Camera (NaTeCam) on the Zhurong rover, which involves utilizing a semi-spherical model (SSM) to characterize the camera's attitude, a projection model (PM) to connect the image data with the three-dimensional (3D) environment, and then estimating the distance and size of rocks. We conduct a test on NaTeCam images and find that the method is effective in measuring the distance and size to Martian rocks and identifying rocks at specific locations. Furthermore, an analysis of the impact of uncertain factors is conducted. The proposed RACP method offers a reliable solution for automatically analyzing the rocks on Mars, which provides a possible solution for the route planning in similar tasks.