Using an UAV for Testing an Autonomous Terrain-based Optical Navigation System for Lunar Landing

This paper presents the application of a rotary wing Unmanned Aerial Vehicle (UAV) as a testbed for the optical navigation system developed in the project "Autonomous Terrain-based Optical Navigation" (ATON) of the German Aerospace Center (DLR). Since using optical sensor data in navigation systems for exploration missions is a promising technology, many projects have focused on the development of such navigation systems. To allow autonomous operation of these developed navigation technologies in the targeted environment extensive testing is necessary for achieving an appropriate grade of reliability. A review of the current approaches for true-scale testing of optical navigation systems for lunar or planetary landing missions is conducted, and the proposed testing methodology is motivated. The paper describes the development steps necessary to conduct closed-loop real-time flight tests using a rotary wing UAV. This includes the sensor configuration, preparation of the flight test area and ground truth generation. Finally, the resulting navigation performance of the ATON navigation system in the closed-loop real-time flight tests is presented.