Adaptive Terrain Relative Navigation for Space Applications

摘要

In space exploration, the autonomous landing of the space vehicle on the surface of a celestial destination under a wide range of surface texture and lighting conditions is a challenging and formidable task. The space vehicle must detect and avoid hazards and touchdown softly and accurately at the intended location. Effective terrain relative navigation can significantly improve the safety and success rate for all crewed and robotic space vehicles designed to land on the moon, other near-earth objects including asteroids and Mars. Precision landing is best accomplished by collecting and fusing synergistic set of measurements providing surface situational awareness to refine the guidance and navigation solution leading to touchdown. Potential sources of independent and synergistic measurements need to be investigated for terrain relative navigation. In this paper, we discuss a process for establishing the required sensing conditions and sensors for terrain relative navigation for space exploration applications. We will present an adaptive fusion approach for generalized terrain relative navigation which is applicable to various landing missions using different sensors. Our adaptive navigation approach provides timely fusion of all measurements that may be available at any given time during the landing mission and has an abstraction software layer implemented for all sensor measurements to enable plug-and-play of any sensors and IMU devices. Our adaptive navigation approach is a software solution that can be easily integrated on existing and future platforms supporting wide range of space landing missions. An overview of the simulation and the results of the flight demonstration of the methodology are provided in this paper.