Detection of orbital debris in low Earth orbit

Abstract

The ever increasing satellite population in near-Earth orbit has made the monitoring and tracking of active satellites, and orbital debris objects ever more critical. As the in-orbit population grows, so does the risk of a collision. In recent years, the European Space Agency (ESA)’s Space Situational Awareness (SSA) programme has been assisting national institutions in the upgrading of their space detection and monitoring capabilities. One of the latest such systems within this programme is the BIstatic RAdar for LEo Survey(BIRALES) space surveillance system consisting of a radio transmitter in Caligari, Sardinia and the BEST-2 phased array in Medicina, near Bologna, Italy. This research lays out the foundation for a new space debris detection system for this novel sensor. First, this work introduces a new software backend that makes use of data processing pipelines to process the incoming data from the 32-antenna radio telescope in real-time. The detection pipeline channelises and beamforms the incoming antenna signals, creating a multi-pixel of beams covering the Field of View (FoV) of the instrument. The detection algorithm uses a series of filters to pre-process the incoming data from any interference. In this study, two novel track detection algorithms are presented. These algorithms identify the unique doppler echo tracks emanating from resident space objects crossing the FoV of this bi-static radar. Candidates are identified by these algorithms are validated to reject false positives. The trajectory of the detected objects is determined by considering the illumination sequence of the multi-pixel. Initial experimental results from observation campaigns of known objects show that the radar can reliably detect in-orbit objects down to a few centimetres in size in Low Earth Orbit (LEO). These encouraging results represent the latest scientific contribution from Europe’s emerging space debris monitoring radar within its growing network of European Space Surveillance and Tracking (SST) systems.