Mitigation of deep space two-line element set biases with pseudo-orbit determination and data-driven models
Author(s)
Hallgarten La Casta, Max Inigo
Type
Thesis
Abstract
The past decade has seen a dramatic growth in the number of Resident Space Objects (RSOs) in near-Earth orbits, driven by the rise of the ‘New Space’ era and the increasing commercialisation of space. The growing congestion in key orbital regimes presents a threat to the continued human presence in space, due to the risk of collisions and their downstream impacts.
The limited availability of data remains a key obstacle for many Space Situational Awareness (SSA) stakeholders. This poses major challenges for ensuring safe and sustainable space operations, including safeguarding transparency of the near-Earth space environment, beyond only operators and governmental organisations. Two-Line Element Sets (TLEs) published by the United States Space Force (USSF) remain one of the few publicly available, comprehensive sources of SSA information. However, their known inaccuracy and uncertain precision limits their utility for many applications.
In this thesis, further investigation into TLE enhancement techniques was conducted, including demonstration of the continuing applicability of TLE-based Pseudo-Orbit Determination (P-OD) to extract improved state estimates from TLEs; presentation of further evidence of widespread, systematic biases affecting deep space TLEs; and modelling of TLE biases to improve TLE-derived state vectors. These techniques were demonstrated for various RSOs in Medium Earth Orbit (MEO) and Geostationary Earth Orbit (GEO), both with and without high-accuracy reference ephemerides, to pave the way for catalogue-wide TLE enhancement.
The limited availability of data remains a key obstacle for many Space Situational Awareness (SSA) stakeholders. This poses major challenges for ensuring safe and sustainable space operations, including safeguarding transparency of the near-Earth space environment, beyond only operators and governmental organisations. Two-Line Element Sets (TLEs) published by the United States Space Force (USSF) remain one of the few publicly available, comprehensive sources of SSA information. However, their known inaccuracy and uncertain precision limits their utility for many applications.
In this thesis, further investigation into TLE enhancement techniques was conducted, including demonstration of the continuing applicability of TLE-based Pseudo-Orbit Determination (P-OD) to extract improved state estimates from TLEs; presentation of further evidence of widespread, systematic biases affecting deep space TLEs; and modelling of TLE biases to improve TLE-derived state vectors. These techniques were demonstrated for various RSOs in Medium Earth Orbit (MEO) and Geostationary Earth Orbit (GEO), both with and without high-accuracy reference ephemerides, to pave the way for catalogue-wide TLE enhancement.
Version
Open Access
Date Issued
2025-09-29
Date Awarded
2026-06-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Amato, Davide
Publisher Department
Department of Aeronautics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)