Motion Compensation Algorithm for Online Digital Elevation Map Generation Using Scanning LIDAR Data

Renewed interest in lunar and eventually Martian surface exploration and science has resulted in increased demand for precision landing capabilities to safely deliver vehicles as close as possible to the desired target landing site. A recent technology under development to facilitate safe precision landing, the NASA Goddard Space Flight Center’s hazard detection LIDAR (HDL), is designed to provide online digital elevation maps (DEMs) of the local terrain, without a requisite vehicle hover to perform the scan. The HDL produces a DEM in the presence of motion by applying a motion compensation algorithm developed by the Safe and Precision Landing Integrated Capabilities Evolution (SPLICE) navigation team. The algorithm is tailored to meet the strenuous requirements necessary to produce a real-time DEM by balancing computational complexity and accuracy. This paper details the algorithm for motion compensation, assumptions and simplifications necessary to deploy it on the HDL field programmable gate array (FPGA), sensitivities of the output point cloud to the aforementioned modifications, and results from HDL helicopter flight testing.