Common-View Time Comparison Orbit Error Screening for Space Stations
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Solution Overview
Problem
The low orbital altitude of space stations amplifies orbit error, limiting the precision of common-view time comparison between space stations, which is a primary factor affecting precision beyond 700 picoseconds.
Innovation Solution
A method to correct orbit error by identifying observation points with high spatial correlation of orbit error between two stations, using elevation and azimuth angles to calculate projection coefficients, and setting decision thresholds to limit orbit error influence within 300 picoseconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the space station operates at low orbital altitude to maintain proximity to ground stations, then communication efficiency is improved, but orbit error is amplified affecting time comparison precision
Solution Approach 1:
The patent applies preliminary action by calculating projection coefficients of orbit error in line-of-sight directions before performing time comparison. The method pre-computes the relationship between orbit error and time comparison error using elevation and azimuth angles, then uses these pre-calculated coefficients to correct the time comparison data, thereby eliminating the amplification effect of low-orbit characteristics on orbit error
Solution Approach 2:
The patent changes parameters by introducing projection coefficients that depend on elevation and azimuth angles. By calculating how orbit error projects onto the line-of-sight direction for each station based on their angular positions, the method transforms the fixed amplification factor into a variable correction term that accounts for the specific geometric configuration of each observation
2Area of stationary object
If the baseline distance between observation stations is increased to improve spatial coverage, then observation coverage is improved, but orbit error amplification increases
Solution Approach 1:
The patent applies local quality by treating each observation station's error characteristics individually. The method calculates separate projection coefficients for each station based on its specific elevation and azimuth angles to the space station, then combines these localized corrections. This allows the system to handle different geometric configurations optimally while maintaining high precision across various baseline distances
3Measurement precision
If post-event precision orbit data is used with absolute error less than 0.1m to improve correction accuracy, then time comparison precision is improved, but processing complexity increases
Solution Approach 1:
The patent replaces complex iterative mechanical adjustment processes with direct mathematical calculations. Instead of iteratively adjusting orbit parameters to minimize error, the method directly computes projection coefficients from elevation and azimuth angles and applies them as correction terms. This substitution of mathematical computation for iterative mechanical adjustment reduces processing complexity while maintaining high precision
Data Source
AI summary
A method for correcting an orbit error of common-view time comparison of a space station, comprising five parts, i.e., determination of moments when two stations can simultaneously view the space station, calculation of projection coefficients of the orbit error, calculation of a three-dimensional orbit error vector set, calculation of a set of projection differences of the orbit error in line-of-sight directions of the two stations, and threshold decision. By means of calculation of the five parts, the maximum influence quantity of the orbit error on a common-view time comparison result is obtained, observation moments with the maximum influence quantity exceeding a decision threshold are eliminated, and observation points with the influence of the orbit error on the common-view time comparison less than the decision threshold are reserved.