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A Map and Trajectory Merging Method of Overlapping Area for Multiple Mars Rovers*

The exploration of Martian surface covers a large area. The exploration capability and range of a single Mars rover is limited, which can be improved by using multiple Mars rovers. The key technologies to realize the exploration of multiple Mars rovers are map merging and trajectory merging, including similar area searching, overlapping area merging and optimization of Mars rover and feature points. Therefore, a map and trajectory merging method of overlapping area for multiple Mars rovers is presented in this paper. Considering the sparsity of image descriptor, the similarity scoring function based on L1 norm is established. And then threshold suppression algorithm is used to select the similar images and eliminate the low similarity images. Meanwhile the consecutive sequence of similar images is selected as overlapping area. The pose transformation relationship of two Mars rovers in overlapping area can be solved, which is used as the initial value of optimization of Mars rover pose and 3D point cloud. Finally, the map and trajectory merging result is obtained. The simulation results and ground tests show that the merging method presented in this paper can quickly search overlapping area. The merging result of map and trajectory has a high accuracy.