ABSTRACT
Overview
Satellite conjunction assessment depends on predicting the future states of objects in orbit. These predictions are inherently dependent on the force models, numerical methods and assumptions used by an orbit propagator.
This research investigates whether the divergence between independently constructed propagation models can be quantified and used as an early-warning metric for the growth of prediction uncertainty.
Rather than treating a single propagation result as the definitive prediction, the study examines how multiple models evolve from the same initial state and how their relative disagreement changes with propagation time.
The objective is to determine whether model divergence contains useful information about the reliability of long-term predictions and whether it could complement existing conjunction-assessment methods.
RESEARCH QUESTION
Central question
Can the divergence between orbital propagation models be quantified in a physically meaningful way and used as an early-warning metric for increasing uncertainty in satellite conjunction assessment?
METHODOLOGY
Research approach
01 · PROPAGATION
Independent force models
Multiple orbital propagation models are constructed with different levels of physical fidelity and different force-model assumptions.
02 · COMPARISON
State divergence
The resulting position and velocity states are compared throughout the propagation period to quantify how rapidly the models diverge.
03 · ANALYSIS
Physical interpretation
Divergence is analysed in relation to orbital regime, perturbation environment, propagation duration and the forces represented by each model.
04 · APPLICATION
Conjunction assessment
The study evaluates whether model disagreement could provide useful information about the reliability of future state predictions.
FORCE MODELS
Physical effects
The appropriate force model depends on the orbital regime and the question being investigated.
Gravity
Central-body gravity and, where appropriate, higher-order gravitational harmonics are considered as part of the orbital dynamics.
Atmospheric drag
Atmospheric drag can become a significant perturbation for objects in lower Earth orbits and is therefore relevant to model fidelity and prediction divergence.
Solar radiation pressure
Radiation pressure is considered where its contribution becomes relevant to the evolution of the spacecraft state.
Third-body effects
Gravitational perturbations from bodies such as the Moon and Sun can become increasingly important outside lower orbital regimes.
RESULTS
Results & analysis
Results will be presented here as the research develops. This section will contain numerical comparisons, plots, error analysis and interpretation of the propagation experiments.
The analysis will distinguish between numerical divergence, differences caused by force-model assumptions and genuine growth in physical prediction uncertainty.
DOCUMENTATION