Abstract: NASA is interested in the ability of an autonomous spacecraft lander to safely touch down on a Martian surface. This is a non-trivial task in that there is evidence from Viking II data that the Martian terrain contains areas that are hazardous for landing. Satellite image data acquired prior to deorbit does not provide sufficient resolution to reliably determine safe landing areas. Therefore the task of hazard detection and avoidance must be performed autonomously and in real time on board a spacecraft lander. A trade study has been performed by ERIM in which several sensor concepts were considered for the autonomous hazard detection and avoidance scenario. The sensor types investigated were laser radar, passive/laser combination, passive hybrid interferometric imager, and synthetic aperture radar (SAR). Of these sensor types, laser radar was selected as the most technically feasible. A sophisticated 3-D laser radar simulation has been developed and has been used to model active sensor measurements from a spacecraft lander. The simulation requires as inputs a simulated Martian terrain elevation map and a spacecraft lander trajectory. Image processing algorithms have been implemented to generate hazard maps from simulated laser radar imagery. Probability of detection versus false alarm curves have been generated by comparing sensor hazard maps with ground truth. This paper describes in detail the sensor simulation, the image processing hazard detection algorithms, and a planned parametric study designed to estimate hazard detection performance of a 3-D laser radar as a function of the critical parameters that affect spatial resolution and signal-to-noise ratio (SNR).!
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