Stellar Atmospheric Refraction Correction via Collinearity Principle
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Solution Overview
Problem
Existing methods for real-time and high-precision stellar atmospheric refraction correction in ground-based star sensors are inadequate due to reliance on theoretical models that do not account for varying refractive indices and require additional instruments, leading to measurement errors and inability to correct multiple stars in real-time.
Innovation Solution
A method based on the collinearity of refraction surfaces, which identifies matching relationships between observation and reference stars, converts direction vectors, and uses least squares error models to correct stellar positions without relying on environmental factors or propagation trajectories, enabling real-time correction of multiple stars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the theoretical uniformly layered spherical atmospheric model is used for atmospheric refraction correction, then the correction method is simple to implement, but the accuracy is insufficient because the model cannot satisfy the isotropic and uniform properties of the actual atmosphere
Solution Approach 1:
The patent replaces the traditional mechanical/optical measurement system with a computational approach. Instead of using physical instruments to measure atmospheric parameters, the system uses image processing and coordinate transformation algorithms to calculate and correct atmospheric refraction effects on star positions, achieving both simplicity and high accuracy through mathematical modeling.
Solution Approach 2:
The patent transforms the correction approach by changing from using atmospheric physical parameters (pressure, temperature, humidity) to using observational parameters (star position coordinates, imaging plane data). This parameter transformation allows the system to bypass the limitations of theoretical atmospheric models and achieve accurate correction based on actual observations.
2Reliability
If additional instruments are used to measure environmental parameters (temperature, pressure, humidity) for correction, then the correction can be performed, but measurement errors from these instruments are introduced and affect accuracy
Solution Approach 1:
The patent extracts the essential correction function from the complex system of environmental sensors and theoretical models. By removing the need for temperature, pressure, and humidity measurements, the system achieves correction capability through pure coordinate transformation based on star position data, eliminating the source of measurement errors.
Solution Approach 2:
The system uses the star sensor's own imaging data to perform correction without external instruments. The star positions captured by the sensor itself provide the necessary information for calculating refraction effects, making the system self-sufficient and avoiding errors from separate measurement devices.
3Productivity
If the look-up table method or uniform spherical model is used, then correction can be accomplished, but the system cannot correct atmospheric refraction for multiple stars at changing observation positions in real time
Solution Approach 1:
The patent creates a universal correction method that works for any star position and any observation configuration. The coordinate transformation algorithm can simultaneously correct positions of multiple stars regardless of their locations in the sky or the sensor's orientation, providing both real-time performance and multi-star capability.
Solution Approach 2:
The system uses dynamic coordinate transformation that adapts to changing observation positions in real time. Unlike static look-up tables, the algorithm continuously calculates corrected positions based on current star coordinates and sensor orientation, enabling real-time correction for moving targets and changing observation geometries.
Data Source
AI summary
A stellar atmospheric refraction measurement correction method based on collinearity of refraction surfaces, comprising: performing star identification on the basis of observed star vectors in a star sensor and the reference star catalog, to obtain matching relationships between observed stars and reference stars; converting reference star vectors corresponding to the observed stars to a geographic coordinate system before entering the atmosphere to obtain zenith distances and azimuth angles of incident stellar; on the basis of a principle of collinearity of refraction surfaces, performing optimal solving according to imaging coordinates of observation stars, to obtain the optimal position coordinates of the zenith direction on an imaging surface of the star sensor; according to the optimal zenith direction, performing atmospheric refraction correction on all the recognized observed stars by means of the trigonometric cosine formula to obtain corrected star coordinates; and performing optimal solving to obtain the attitude of the star sensor in the geographic coordinate system.