Motion-Compensated Correlation for Positioning Accuracy
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Solution Overview
Problem
Existing methods for correlating digital signals and correlation codes in communication systems face challenges due to noise and multipath effects, which degrade signal-to-noise ratios and reduce positioning accuracy, especially in environments with weak signals and multipath conditions.
Innovation Solution
A positioning system that includes a local signal generator, a receiver, a motion module, and a correlation unit, which applies motion compensation to the local and received signals based on measured or assumed movement, enhancing the correlation of line-of-sight signals and suppressing non-line-of-sight signals by using motion-compensated correlation sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional correlation methods are used without motion compensation, then the system is simpler to implement, but positioning accuracy deteriorates due to noise and multipath effects
Solution Approach 1:
The system performs preliminary motion compensation on the correlation code by applying phase adjustments based on predicted receiver motion before the correlation process. This pre-compensation prepares the signals to counteract expected multipath effects and noise, improving positioning accuracy without adding complex real-time processing during correlation
Solution Approach 2:
The patent introduces motion compensation as an intermediary processing step between signal reception and correlation. This intermediary layer adjusts the correlation code based on motion parameters, acting as a mediator that reduces the impact of noise and multipath effects before the main correlation operation
2Measurement precision
If longer coherent integration periods are used to improve signal-to-noise ratio, then positioning accuracy improves, but the system becomes more sensitive to phase changes and motion effects
Solution Approach 1:
The system applies preliminary anti-action by pre-compensating the correlation code for expected phase changes due to motion. By calculating and applying opposite phase adjustments based on predicted receiver movement, the system counteracts the harmful effects of motion before they can degrade the correlation over long integration periods
Solution Approach 2:
The patent implements dynamics by making the correlation code adaptive to receiver motion. The system continuously updates the motion compensation parameters based on measured or assumed receiver movement, allowing the correlation process to dynamically adjust to changing conditions and maintain high signal-to-noise ratios over extended integration periods
3Measurement precision
If motion compensation is applied to preferentially amplify line-of-sight signals, then positioning accuracy improves, but non-line-of-sight signals may be incorrectly suppressed
Solution Approach 1:
The system changes parameters by applying selective phase compensation based on motion parameters. By adjusting the phase of the correlation code according to predicted receiver motion, the system enhances line-of-sight signals while the multipath suppression emerges as a beneficial side effect, not through direct suppression but through preferential amplification of the correct signal path
Data Source
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AI summary
A method, apparatus, computer program, data structure, signal relating to: causing correlation of a digital signal provided by a receiver with a motion-compensated correlation code, wherein the motion-compensated correlation code is a correlation code that has been compensated before correlation using one or more phasors dependent upon an assumed or measured movement of the receiver.