LIDAR Based Landing Site Identification and Safety Estimation For Inter Planetary Missions

Development of the real time landing site identification and safety estimation technology is of much importance for the exploration of extraterrestrial bodies. LiDAR has become a vital element in such system due to its high accuracy, good object detection and distance estimation capability and ability to operate under any illumination condition. In this paper a LiDAR based landing site identification and safety estimation technique for inter planetary missions is proposed. A two step approach is proposed in this work. Initial coarse estimation by means of outlier detections. Fine estimation by means of landing safety assessment by computing roughness and slope within the vehicle parameter. The data is regularized by re-gridding the data and the outlier is eliminated by setting a threshold value; closely spaced outliers are identified as potential hazards like rocks, craters. K nearest neighbour interpolation is used for filling the elevation values where outliers located. Thin Plate Spline (TPS) interpolation is used for surface reconstruction. The gradient value of a TPS surface and the original surface are used to estimate slope. The residual between the surface recreated using TPS and the filtered Digital Elevation Model is used to calculate roughness. Final risk map in the landing site is the combination of the slope and roughness map. The validation of the algorithms are done using data collected by an Aerial Laser Scanner(ALS).