Satellite Phase Ambiguity Resolution Using Multi-Frequency Pseudo-Paths
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Solution Overview
Problem
Current satellite-based positioning systems face limitations in achieving high accuracy and short initialization times due to the reliance on identical frequencies for pseudo-path and phase-path measurements, which restricts the flexibility and precision of phase ambiguity resolution.
Innovation Solution
The method involves using pseudo-paths and carrier phases from selected carrier frequencies, allowing for the combination of two carrier phases with at least one additional frequency for pseudo-path determination, enabling the use of frequencies without coding and improving measurement accuracy by smoothing pseudo-path measurements with carrier phase data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If identical frequencies are used for both pseudo-path and phase-path measurements, then the measurement process is simplified, but the flexibility and precision of phase ambiguity resolution is restricted
Solution Approach 1:
The patent segments the frequency usage by assigning different frequencies to pseudo-path measurements and phase-path measurements. Specifically, it uses frequencies from a first set for pseudo-path measurements and frequencies from a second set for phase-path measurements, where the sets can be different. This segmentation allows independent optimization of each measurement type while resolving the ambiguity through the combination of both measurement sets.
2Measurement precision
If carrier phases are measured at multiple frequencies, then measurement precision is improved, but the initialization time increases
Solution Approach 1:
The patent performs preliminary actions by establishing the relationship between different frequency measurements and preparing the system to resolve ambiguities more efficiently. By pre-establishing which frequencies to use for pseudo-path versus phase-path measurements and how to combine them, the system reduces the computational burden during initialization, thereby reducing initialization time while maintaining high precision through multi-frequency measurements.
3Object-affected harmful factors
If real-value factors are used in linear combinations, then ionospheric delays are corrected, but the integral nature of phase ambiguity is destroyed
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different frequency components. It uses real-value factors specifically for ionospheric delay correction in the linear combinations, while preserving the integral nature of phase ambiguity through the selective combination of pseudo-path and phase-path measurements. This allows the system to correct ionospheric effects locally without destroying the overall integral property needed for ambiguity resolution.
Data Source
AI summary
The invention relates to a satellite-based positioning system in which a transmitter (2) emits electromagnetic radiation at least at N≧3 carrier frequencies (3, 4, 5). In order to resolve the phase ambiguity for said satellite-based positioning system, the electromagnetic radiation is received by a receiver (1), and K pseudo paths (3a, 4a, 5a, 6a) and L carrier phases (3b, 4b, 5b, 6b), especially at least two pseudo paths (3a, 5a) and at least two carrier phases (3b, 4b), are derived from the received radiation as M pieces of distance data, wherein M=K+L. In order to determine the position, the integer phase ambiguity is derived from the linear combination of a maximum of M≦2N−1 pieces of distance data.