V2X Positioning Synch-Vector Integer Ambiguity
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Solution Overview
Problem
Current methods for determining distance information using signal phase in vehicle-to-everything (V2X) communication systems face challenges in precision due to integer ambiguity issues, especially when trying to measure distances less than 10 meters with high frequency signals, which is crucial for accurate autonomous vehicle navigation.
Innovation Solution
The method involves using a synch-vector to correct for time errors and propagation delays in positioning reference signals, allowing for the determination of synchronized positioning reference signals and subsequent accurate distance measurement by converting phase difference information into phase difference values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high frequency signals are used for distance measurement, then measurement precision is improved, but integer ambiguity issues worsen
Solution Approach 1:
The patent segments the distance measurement process into two stages: first using phase difference information from high frequency signals to achieve fine precision measurement, then using time of arrival information to determine the integer ambiguity (coarse range). This segmentation allows the system to benefit from both high precision and reliable integer determination.
Solution Approach 2:
The patent introduces time of arrival information as an intermediary element that mediates between the high frequency phase difference measurements and the final distance calculation. This intermediary helps resolve the integer ambiguity by providing a reference framework that bridges the gap between precise but ambiguous phase measurements and accurate but less precise time-based measurements.
2Measurement precision
If smaller wavelength is used for positioning, then positioning precision is improved, but period of phase value becomes ambiguous
Solution Approach 1:
The patent segments the positioning information into two components: phase difference information (providing precise fractional wavelength measurements) and time of arrival information (providing complete wavelength period information). By combining these segmented information sources, the system recovers the complete positioning information that would otherwise be lost due to phase wrapping.
Solution Approach 2:
The patent changes the parameter domain by transforming the problem from purely phase-based measurement to a hybrid approach that incorporates time domain measurements. This parameter change allows the system to access different information dimensions, where time of arrival provides the missing period information that complements the phase difference measurements.
Data Source
AI summary
Provided is a positioning method performed by a node device receiving a positioning reference signal transmitted from another node device, wherein the positioning reference signal comprises a time error and a propagation delay. The positioning method includes determining, a synch-vector based on the time error and the propagation delay, wherein the synch-vector is configured to remove the time error or the propagation delay. Further, the positioning method includes applying the synch-vector to generate a synchronized positioning reference signal that corrects for the time error or the propagation delay. The positioning method can also include determining an unknown integer number of carrier wavelengths based on a phase difference value of the synchronized positioning reference signal, the time error, and the propagation delay.