Satellite Navigation Relative Positioning Ambiguity Resolution
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Solution Overview
Problem
Current satellite navigation systems face challenges in accurately determining the relative position between two receivers due to the ambiguity of phase measurements, particularly with small carrier wavelengths and multipath effects, which affect the reliability of integer ambiguity resolution.
Innovation Solution
A method that involves determining position parameters by searching candidate phase ambiguities, maximizing the a-posteriori probability under phase measurement conditions, and using soft constraints on baseline orientation to reduce the search space and improve ambiguity resolution, incorporating a search tree and adjustable probability limits to enhance the reliability of ambiguity resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase measurements on carrier signals are used for determining relative position, then measurement precision is improved, but reliability of ambiguity resolution deteriorates due to small carrier wavelength and multipath effects
Solution Approach 1:
The patent transforms the original carrier phase measurements into linear combinations with different wavelengths (including widelane combinations with several meters wavelength). This parameter transformation changes the measurement characteristics to improve ambiguity resolution reliability while maintaining positioning precision through the use of multiple frequency combinations
Solution Approach 2:
The patent creates composite measurement models by combining multiple frequency carrier phase measurements and code measurements into unified linear combinations. These composite measurements integrate information from different signal types and frequencies to achieve both high precision and reliable ambiguity resolution
2Productivity
If the search space for integer ambiguity resolution is reduced using constraints, then productivity is improved, but device complexity increases due to the need for constraint modeling and evaluation
Solution Approach 1:
The patent transforms physical constraints on baseline length and orientation into probabilistic constraints with adjustable confidence levels. This parameter transformation allows the system to dynamically adjust constraint tightness based on measurement quality and application requirements, simplifying the search process while maintaining flexibility
Solution Approach 2:
The patent implements dynamic constraint adjustment where the tightness of baseline length and orientation constraints can be modified during the ambiguity resolution process. The system adapts constraint parameters based on the quality of float solutions and measurement conditions, optimizing the balance between search efficiency and solution accuracy
Data Source
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AI summary
A method for determining the relative posision between two recievers includes the method steps: - the position parameters of the relative position are determined by searching integer candidate phase ambiguities, that - for each integer candidate phase ambiguity associated position parameters of the relative position are determined, which are maximizing an a-posteriori-probability for the position parameters under the condition of the phase measurement, and that - the final integer candidate phase ambiguity and the position parameters associated with the final integer candidate phase ambiguity are selected by evaluating a final cost function, which is arranged for evaluating the deviation of the candidate integer phase ambiguity and position parameters from estimates of the integer phase ambiguities and the position parameters