Breadboard model of a 3D LIDAR sensor for real-time pose estimation of spacecraft

Abstract

Reliable relative navigation between two spacecraft is a critical element of future On Orbit Servicing (OOS) missions and space debris removal scenarios. Sensors are required that allow for accurate estimates of a target satellite’s relative position and attitude. Scanning LiDAR (Light RADAR, also Light Detection And Ranging) based sensors are capable of creating a three dimensional point cloud of the target satellite, widely immune to varying illumination conditions. In this context, a 3D LiDAR sensor for real-time tracking and pose estimation of a target satellite is developed at the German Space Operations Center (GSOC), part of the German Aerospace Center (DLR). It is intended as an on-ground research platform for development and test of LiDAR related algorithms and concepts. The sensor is based on a commercial 2D laser scanner which is extended by an additional high precision rotary axis. An integral part of the hardware is a smart adjustment mechanism allowing precise mechanical calibration of the sensor, thereby optimizing the coverage by the scanning pattern and simplifying the necessary software models for measurement evaluation considerably. Scanner and axis are synchronized by continuous high frequency sampling of the axis angle. For controlling the sensor and for real-time pre-processing of the raw range data an embedded system is used. First tests were conducted in a robotic Rendezvous and Docking laboratory (European Proximity Operations Simulator - EPOS), involving realistic illumination conditions. This paper outlines hardware design, sensor control and processing architecture of the LiDAR sensor breadboard. Results of first tests, including accuracy and sensitivity to illumination, are presented and discussed.