William Ediger, University of Manitoba; Yue Ma, C-CORE; Matthew Driedger, Magellan Aerospace; Alex Gmerek, Carleton University; Renmar Khim Palma, University of Manitoba; Paul Harrison, Magellan Aerospace; Michael Berezin, Magellan Aerospace; Philip Ferguson, University of Manitoba; John Spray, HIT Dynamics; Alex Ellery, Carleton University; James Kennedy, C-CORE
Keywords: SSA, Orbit Determination, Laser Ranging, SAR Imaging, Remote Sensing, Detection and Tracking, Collision Avoidance
Abstract:
As the number of spacecraft in orbit around the Earth continues to increase, so does the population of derelict satellites and other space debris, collectively known as Resident Space Objects (RSOs). Space-based Space Situational Awareness (SSA) platforms are becoming more critical to identify and track RSOs, which is necessary to prevent on-orbit collisions and the further propagation of RSOs. However, the cost and development time necessary for dedicated SSA missions mean that not enough SSA platforms are available. Those dedicated space-based SSA observatories that are available, such as Sapphire and NEOSSAT, are limited in number and are focused on tracking full-size satellites. Additionally, most SSA satellites rely on angle-based optical tracking methods, which have difficulties in establishing a full orbital solution for a detected object on their own and would greatly benefit from time-of-flight information to provide complete orbital solutions. This paper describes current efforts by Magellan Aerospace, the University of Manitoba, Carleton University, HIT Dynamics Ltd, and C-CORE to develop time-of-flight based sensors and techniques that can be used to contribute to orbital SSA capabilities as a part of our ongoing SPACEDUST (Special Processes and Advanced Computing Environment for Detection, Unambiguity, Surveying, and Tracking) project. Specifically, this paper presents the preliminary design and testing of a combined optical-laser ranging sensor and techniques for extracting RSO-range data from Synthetic Aperture Radar (SAR) images.
The combined optical-laser ranging sensor is designed to be a self-contained SSA payload that can be included on future satellites with a minimal impact on their primary missions. The sensor consists of a machine-learning-capable optical cueing camera, steerable mirror, laser rangefinder, and a controller. When combined, this sensor can provide users with relative RSO angle and range data which can be used to reconstruct the object’s orbit. Based on our preliminary analysis, we expect this sensor to have a detection range that is sufficient to supply SSA data during conjunction events and to provide proximity-warning capabilities to the host spacecraft. This paper presents the preliminary engineering design for this sensor, including initial laboratory results, and discusses additional future laboratory and field tests. The initial laboratory tests include validating the optical-laser ranging sensor’s performance when detecting fixed targets. The future laboratory tests will include additional functional testing of the optical-laser ranging sensor when detecting slow-moving targets with angular speeds less than 1 deg/s, as well as material reflectance measurements to determine the optical-laser sensor’s maximum expected range. The material reflectance measurements will use a separate apparatus, based on a 2.7 µm bench-top distributed feedback laser. Future field testing will consist of tracking a fast-moving target, dropped from a helicopter, with the optical-laser ranging sensor mounted on an aerial drone, to emulate the high angular rates that occur during an orbital conjunction event.
The second SSA method examined in this paper explores how RSO ranging data could be extracted from SAR images. SAR is commonly used for Earth observation and numerous SAR-equipped satellites are currently operating in orbit. These instruments function by transmitting radio waves as the SAR antenna moves over Earth-based targets, receiving the reflected signals, and processing the returned signals to extract target information. These reflected signals also contain reflections from spacecraft and other RSOs orbiting between the SAR antenna and target. Currently this RSO data is filtered out as noise. However, if RSO data could be extracted from SAR imagery, these sensors would significantly improve SSA capacity due to their sheer quantity and duty cycles. This paper presents work performed by Magellan Aerospace and C-CORE to extract RSO data from unprocessed SAR imagery data.
Based on the preliminary work presented in this paper, both the combined optical-laser ranging sensor and SAR image extraction algorithm are promising methods for augmenting SSA capabilities. The combined optical-laser ranging sensor can enable host spacecraft to aid in SSA activities while providing the spacecraft with off-the-shelf proximity-warning capabilities. The SAR image extraction method allows Earth observation spacecraft to provide SSA services without impacting their primary mission. Together, these methods will allow more spacecraft to contribute to SSA, thereby making space safer and more sustainable.
Date of Conference: September 19-22, 2023
Track: SDA Systems & Instrumentation