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Performance Bounds for Cooperative Localisation in the Starlink Network

By Keith Cowing
Press Release
July 18, 2022
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Performance Bounds for Cooperative Localisation in the Starlink Network
Starlink satellites awaiting deployment

Mega-constellations in Low Earth Orbit have the potential to revolutionise worldwide internet access.

The concomitant potential of these mega-constellations to impact space sustainability, however, has prompted concern from space actors as well as provoking concern in the ground-based astronomy community. Increasing the knowledge of the orbital state of satellites in mega-constellations improves space situations awareness, reducing the need for collision avoidance manoeuvres and allowing astronomers to prepare better observational mitigation strategies.

In this paper, we create a model of Phase 1 of Starlink, one of the more well-studied megaconstellations, and investigate the potential of cooperative localisation using time-ofarrival measurements from the optical inter-satellite links in the constellation.

To this end, we study the performance of any unbiased estimator for localisation, by calculating the instantaneous Cramé r-Rao bound for two situations; one in which inter-satellite measurements and measurements from ground stations were considered, and one in which only relative navigation from inter-satellite measurements were considered.

Our results show that localisation determined from a combination of inter-satellite measurements and ground stations can have at best an an average RMSE of approximately 10.15 metres over the majority of a satellite’s orbit. Relative localisation using only inter-satellite measurements has a slightly poorer performance with an average RMSE of 10.68 metres.

The results show that both anchored and anchorless inter-satellite cooperative localisation are dependent on the constellation’s geometry and the characteristics of the inter-satellite links, both of which could inform the use of relative navigation in large satellite constellations in future.

Calum Spring-Turner, Raj Thilak Rajan

Comments: In submission
Subjects: Systems and Control (eess.SY); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2207.04691 [eess.SY] (or arXiv:2207.04691v1 [eess.SY] for this version)
Submission history
From: Raj Thilak Rajan
[v1] Mon, 11 Jul 2022 08:12:45 UTC (8,986 KB) Full paper

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