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Space Based Radar and Optical Surveillance System for LEO small space debris high accuracy orbit determination



Organisational Unit
Activity Type
24 April 2024

Duration: 12 months


Small space debris (<10cm) are a growing threat for space operations, especially in LEO. They are numerous (900 000) and mostly uncatalogued by ground systems due to their small size.Space Based Surveillance Systems (SBSS) is one of the solutions to maintain the state vector covariance of catalogued debris population within the extremely challenging accuracy requirement for LEO debris of [40,200,100]m in QSW frame, 48h following last observation. Most SBSS concepts do not achieve directly the Initial Orbit Determination (IOD) as they do not provide enough information per observation. They require the capability to “crack” the successive Very Short Arcs correlation challenge, of paramount difficulty for small LEO debris due to their abundance and their adverse surface to mass ratio (wrt high uncertainty surface forces). The novel concept proposed by Airbus aims at providing the ability to perform small debris IOD with exquisite accuracy with 1 observation. The system consists of 2 satellites on the same LEO orbit, with a ~ 100 km baseline. Each satellite embarks accurate and independent debris measurements sensors: Optical surveillance instrument for angular positions
and innovative very high frequency and low noise radar – with an antenna shaped and aligned to match the optical instrument LoS and FoV - for debris range and range rate. The 2 radars, operated in alternated bi static mode, provide also additional sum of ranges and range rates information. An intersatellite link enables GNSS navigators and radars synchronization. The satellites pair provides a 10 components information vector with geometrical diversity. Such configuration allows retrieval of debris state vector with exquisite sub-metric accuracy. This system, limited to few pairs of IOD satellites, would be ideally complemented by smaller, simpler optical satellites, deployed in larger amounts and tasked to provide high revisit performance to keep catalogued debris covariance within required boundaries

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