Motion-Compensated Signal Correlation for Weak GPS Positioning
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Solution Overview
Problem
The correlation of digital signals and correlation codes is hindered by noise and multipath effects in communication channels, particularly in environments with weak signals and urban canyons, leading to reduced positioning accuracy in GPS and other navigation systems.
Innovation Solution
A positioning system that incorporates a motion compensation unit to adjust 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, thereby improving positioning accuracy by applying motion compensation to the signals before correlation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion compensation is applied to preferentially amplify line-of-sight signals, then positioning accuracy is improved, but device complexity increases due to the additional motion compensation unit and processing requirements
Solution Approach 1:
The patent applies motion compensation preliminarily to the received signal and local signal before correlation processing. By pre-compensating the signals using measured or assumed receiver motion in the first direction, the system prepares the signals in advance to enhance line-of-sight signal correlation and suppress multipath signals, thereby improving positioning accuracy without requiring complex post-processing
Solution Approach 2:
The patent segments the signal processing into distinct functional components: a motion compensation unit that processes signals based on measured or assumed receiver motion, and a correlation unit that performs the actual correlation. This segmentation allows the motion compensation functionality to be added as a modular component rather than requiring complete system redesign, thus managing device complexity while achieving improved positioning accuracy
2Reliability
If motion compensation is applied to suppress multipath signals, then signal-to-noise ratio is enhanced, but processing time increases due to additional compensation calculations
Solution Approach 1:
The patent applies motion compensation partially by focusing exclusively on compensation in the first direction (the direction of motion between receiver and remote source). This partial action is sufficient to achieve the desired signal-to-noise ratio enhancement by suppressing multipath signals, without requiring full three-dimensional compensation that would consume excessive processing time
Solution Approach 2:
The patent changes the parameter of motion compensation by using measured or assumed receiver motion to determine the compensation amount. This dynamic parameter adjustment allows the system to adapt the compensation level to actual conditions, optimizing the balance between signal-to-noise ratio enhancement and processing time consumption
Data Source
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.