Laurence Blacketer, Raytheon UK; Cameron Guerrero, Raytheon UK; Josh Nicholls, Raytheon UK
https://doi.org/10.64861/FIBI5090
Keywords: SSA, SDA, fixed point-of-view, wide field-of-view, optical, surveillance, optical space fence, sensor system
Abstract:
The Low-Earth Orbit (LEO) Optical Camera Installation (LOCI) network is a network optical space fence surveillance systems, that use wide field-of-view (WFoV), fixed point-of-view (PoV), optical cameras toproduce near-real-time tracking data of Earth-orbiting Resident Space Objects (RSOs).
LOCI sensor systems comprise of three commercial off-the-shelf (COTS) high-end optical astronomy cameras that create an East-West optical space fence through which RSOs transit. The RSOs that transit the FoVs of the cameras present as streaks, which are detected and extracted as timestamped Right Ascension and Declination angles, in the J2000 reference frame. Throughout 2024/2025, four LOCI systems have been deployed. The first was in the Kielder forest, a protected dark-skies location in the north of England. The second system was deployed in the Sierra Nevada mountains region of California, USA. The third system was deployed on the Hawaiian island of O’ahu, USA. The fourth system was deployed in Perth, on the west coast of Australia.
Optical space fence sensors can form a highly effective node in a global Space Surveillance and Tracking network. This is primarily because they are low-cost and can observe any number of objects simultaneously without cueing. The result is a high volume of extremely cost-effective tracking data, on a cost-per-track basis. These systems require no a-priori information to track an RSO, and so are particularly effective at the detection of Uncorrelated Targets (UCTs). Furthermore, theyoperate in an entirely passive and autonomous way, collect tracking data on all objects with an equally high priority, and containzero moving parts during operation. Consequently, the operational and maintenance expense of operating these systems is extremely low.
Another supplemental advantage of optical space fence systems is a capability to generate brightness-over-time data for all observed RSOs – which can be used for characterisation and other Space Domain Awareness (SDA) focused activities. Although this is not a property that is unique to optical space fence systems, the surveillance design of the system allows for a significant increase in the volume of data collected, and for data to be collected for multiple objects simultaneously.
To acquire this set of highly desirable properties, certain performance characteristics are necessarily traded off. The first is accuracy. This results from the requirement to widen the FoV of the individual cameras to compensate for the design choice to not follow the target across the sky. However, this paper presents the accuracy performance of LOCI systems and shows that orbital determination of LOCI data can produce valuable state vector information. The second performance characteristic is minimum detectable object size and is another direct consequence of the widening of the FoVs. However, detection of small (less than or equal to 10 cm) RSOs was not a design objective of the LOCI network, as this is a task that is more ideally suited to radars and large-aperture optical instruments.
In this paper, the design and operation of a LOCI sensor is described. Additionally, the first quantified performance evaluation of LOCIis presented, using real-world operational data. This includes performance statistics in terms of total data volume, tracking accuracy and orbit determination accuracy. The results of this paper show how wide-field, fixed-PoV, optical space fence sensor systems can materially augment global SDA architectures.
Date of Conference: September 15-18, 2026
Track: SDA Systems & Instrumentation