Correlation Calculating Circuit for Satellite Signal Capturing
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Solution Overview
Problem
The correlation calculation amount in GPS satellite signal capturing increases exponentially as the sampling interval is shortened, leading to increased power consumption in the correlation calculating circuit.
Innovation Solution
A method and circuit that correlate received code signal values at first to n-th arrival times by varying the chip period by 1/n chip, synthesizing correlation results to achieve a correlation calculation at a 1/n chip interval, reducing the overall calculation amount and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sampling interval is shortened to improve signal capturing accuracy, then the measurement precision is improved, but the correlation calculation amount increases exponentially
Solution Approach 1:
The patent divides the correlation calculation process into multiple stages: first performing correlation calculation at a coarse sampling interval to identify candidate phases, then refining the search at a finer sampling interval only for those candidate phases. This segmentation reduces the total calculation amount from exponential to linear while maintaining high measurement precision.
Solution Approach 2:
The patent performs a preliminary correlation calculation at a coarser sampling interval before the final fine-interval calculation. This preliminary action identifies promising candidate phases in advance, so that the computationally intensive fine-interval calculation is performed only on a limited set of candidates rather than all possible phases.
2Measurement precision
If the sampling interval is shortened to improve signal capturing accuracy, then the measurement precision is improved, but the power consumption increases
Solution Approach 1:
The patent segments the correlation calculation into coarse and fine stages, performing the power-intensive fine-interval calculations only for candidate phases identified in the coarse stage. This reduces total power consumption while maintaining high measurement precision through the subsequent fine-interval refinement.
Solution Approach 2:
The patent performs a preliminary coarse-interval correlation calculation that consumes less power to identify candidate phases. This preliminary action filters out most phases, so that the high-power fine-interval calculations are executed only on a small subset of candidates, significantly reducing overall power consumption.
3Measurement precision
If the sampling interval is shortened to improve signal capturing accuracy, then the measurement precision is improved, but the processing time increases
Solution Approach 1:
The patent divides the processing into two time-efficient stages: a quick coarse-interval correlation calculation that rapidly identifies candidate phases, followed by a focused fine-interval calculation only on those candidates. This segmentation achieves high measurement precision without the exponential time increase that would result from performing fine-interval calculations on all phases.
Solution Approach 2:
The patent performs a preliminary coarse-interval correlation calculation that quickly identifies candidate phases with promising correlation values. This preliminary action reduces the search space significantly, so that the time-consuming fine-interval calculations are performed on only a few candidates rather than all possible phases.
Data Source
AI summary
A correlation calculating method of correlating a received code signal obtained by demodulating a received signal, which is a signal obtained by receiving a positioning satellite signal, with a replica code signal is provided which includes: correlating values of the replica code signal in a chip period with values of the received code signal at first to n-th arrival times obtained by varying an arrival time of the chip period by 1/n chip (where n is an integer equal to or greater than 2); and acquiring a correlation calculation result at a 1/n chip interval by synthesizing the correlation calculation results.