Satellite Orbit Determination via Parallactic Refraction Scale Factor Estimation
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Solution Overview
Problem
Current satellite orbit determination methods using optical surveillance fail to accurately account for parallactic refraction effects, leading to inferior precision in satellite tracking and collision risk assessment due to excessive refraction corrections.
Innovation Solution
A method that estimates and corrects the parallactic refraction scale factor simultaneously with satellite position and velocity vector determination using a high-precision orbit propagator and batch least square estimation algorithm, incorporating parallactic refraction into the optical observation model to minimize observation residuals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical observation model uses standard refraction correction assuming satellite refractive index equals star refractive index, then the observation model remains simple, but excessive refraction correction occurs leading to inferior orbit determination precision
Solution Approach 1:
The patent introduces a parallactic refraction scale factor as a new parameter that modifies the standard refraction correction. This scale factor accounts for the difference between satellite and star refractive indices, allowing the model to correct the excessive refraction correction while maintaining the overall structure of the observation model. The scale factor is estimated simultaneously with orbit parameters, enabling precision improvement without substantial model complexity increase.
Solution Approach 2:
The patent separates the refraction correction into two components: the standard refraction correction (based on star observations) and the parallactic refraction correction (scaled by the estimated scale factor). This segmentation allows the model to apply only the necessary correction for satellite observations, rather than applying full stellar refraction correction, thereby improving precision while keeping the model manageable.
2Measurement precision
If the optical observation model does not account for parallactic refraction effect, then the model remains simple, but orbit determination precision deteriorates
Solution Approach 1:
The patent introduces a parallactic refraction scale factor as a new parameter that modifies the standard refraction correction. This scale factor accounts for the difference between satellite and star refractive indices, allowing the model to correct the excessive refraction correction while maintaining the overall structure of the observation model. The scale factor is estimated simultaneously with orbit parameters, enabling precision improvement without substantial model complexity increase.
3Measurement precision
If simultaneous estimation of satellite state vector and parallactic refraction scale factor is performed, then orbit determination precision improves, but computational complexity increases
Solution Approach 1:
The patent merges the estimation of the satellite state vector and the parallactic refraction scale factor into a single batch least squares estimation process. By combining these estimations, the algorithm can simultaneously optimize both parameters using all available observation data, improving precision while avoiding the need for separate, complex estimation steps. The unified approach leverages the correlation between state vector and scale factor estimates.
Solution Approach 2:
The batch least squares estimation algorithm provides feedback by using the residuals between observed and computed values to iteratively refine both the satellite state vector and parallactic refraction scale factor. This feedback mechanism allows the algorithm to converge to optimal values for both parameters simultaneously, improving precision while managing computational complexity through efficient iterative refinement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly improves satellite orbit determination precision by accurately accounting for parallactic refraction, reducing prediction errors and enhancing tracking accuracy, thereby mitigating collision risks and ensuring safer satellite operations.
Implementation Method 1
the optical observation model in the related art does not take into account the parallactic refraction effect, and thus has a problem of inferior precision when applied to satellite orbit determination
Data Source
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AI summary
A method of determining a precise orbit of a satellite through estimation of a parallactic refraction scale factor is proposed, the method including inputting an initial estimate including initial orbit information of a satellite with respect to an observation epoch and the parallactic refraction scale factor; performing orbit propagation using a high-precision orbit propagator by applying a dynamics model; performing observer-centered satellite optical observation modeling including the parallactic refraction scale factor; calculating an observation residual between actual optical observation data and observation data calculated via the observation modeling reflecting the parallactic refraction; and precisely determining the orbit of the satellite by estimating the parallactic refraction scale factor and a satellite state vector using a batch least square estimation algorithm.