Spacecraft Relative Positioning via GNSS Ambiguity Search
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Solution Overview
Problem
Existing methods for measuring the relative position of spacecraft using GNSS fail to meet both real-time and high-precision requirements due to limitations in current GNSS technology.
Innovation Solution
A method and apparatus that utilize a double-difference ambiguity search based on pseudo-range and carrier double-difference equations to determine ambiguities of whole cycles, expanding carrier wavelength through linear combinations of GNSS observations, reducing search space and workload, and enabling precise measurement of relative position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional GNSS relative position measurement methods are used, then the measurement can be performed, but both real-time performance and high-precision requirements cannot be simultaneously met
Solution Approach 1:
The patent changes the carrier wavelength parameter by expanding it through linear combinations of multiple frequency observations. This wavelength expansion transforms the carrier phase ambiguity search from a dense short-wavelength problem to a sparse long-wavelength problem, significantly reducing the search space and calculation time while maintaining high measurement precision
Solution Approach 2:
The patent segments the GNSS observation data into multiple frequency combinations (first long-wave observation combination and second long-wave observation combination), processes them separately through double-difference ambiguity search, and then integrates the results. This segmentation divides the complex measurement task into manageable parts, reducing computational burden and enabling real-time processing
2Measurement precision
If double-difference ambiguity search is performed with conventional carrier wavelength, then measurement precision can be achieved, but search space is large and calculation time is excessive
Solution Approach 1:
The patent applies parameter changes by expanding the carrier wavelength through linear combinations of multiple frequency observations. This transforms the search problem from a dense grid of possible ambiguities at short wavelength to a sparse set of possible ambiguities at expanded wavelength, dramatically reducing search space complexity while maintaining the precision needed for accurate ambiguity determination
3Productivity
If multiple frequency observations are combined to expand carrier wavelength, then search space is sparsened and calculation time is reduced, but the complexity of data processing increases
Solution Approach 1:
The patent segments the data processing into distinct modules: acquiring multiple frequency observations, forming long-wave observation combinations, performing double-difference ambiguity search for each combination, determining ambiguities based on preset conditions, and calculating final relative position. This segmentation organizes the complex processing into manageable steps, improving productivity while making the complexity manageable through structured approach
Data Source
AI summary
The present application provides a method and an apparatus for measuring a relative position of a spacecraft based on GNSS difference. The method includes: acquiring a first long-wave observation combination and a second long-wave observation combination; performing a double-difference ambiguity of whole cycles search according to a pseudo-range double-difference linear equation and a carrier double-difference equation, and determining N first ambiguities of whole cycles to be detected of the first long-wave observation combination and M second ambiguities of whole cycles to be detected of the second long-wave observation combination; determining a first ambiguity of whole cycles and a second ambiguity of whole cycles that satisfy a preset ambiguity of whole cycles condition; and then determining a short-wave double-difference ambiguity of whole cycles to measure the relative position of the spacecraft.