Signal Acquisition Method Using Block Averaging for Weak Positioning Signals
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Solution Overview
Problem
In indoor environments with many obstacles, the positioning signals broadcast by a base station undergo significant attenuation, making it challenging for receivers to acquire signals effectively, especially when using PMF-FFT methods that reduce the FFT frequency search range due to long coherent integration times.
Innovation Solution
The method involves dividing received positioning signals into groups, performing frequency compensation, and block averaging to reduce noise power, followed by a PMF-FFT operation to determine the acquisition result based on the peak-to-average ratio, which improves signal-to-noise ratio and acquisition sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coherent integration time is increased to improve weak signal acquisition, then signal-to-noise ratio is improved, but FFT frequency search range is reduced
Solution Approach 1:
The patent divides the received positioning signals into multiple groups and further divides each group into multiple signal blocks. By performing block averaging on these segmented blocks, the method achieves noise reduction while maintaining the ability to search across the full frequency range, resolving the contradiction between integration time and frequency search capability.
Solution Approach 2:
The patent performs block averaging operation on signal blocks before the PMF-FFT acquisition process. This preliminary noise reduction action improves the effective signal-to-noise ratio without requiring extended coherent integration time, thereby preserving the FFT frequency search range while enhancing weak signal acquisition capability.
2Reliability
If coherent integration time is increased to reduce noise power, then signal-to-noise ratio is improved, but acquisition time is extended
Solution Approach 1:
The block averaging operation is performed as a preliminary step before the main PMF-FFT acquisition process. This pre-processing reduces noise power in advance, allowing the acquisition to converge faster and reducing the required coherent integration time, thereby decreasing overall acquisition time while improving reliability.
Solution Approach 2:
Instead of using full coherent integration for noise reduction, the patent applies partial integration through block averaging on segmented signal blocks. This provides sufficient noise reduction for weak signal acquisition without the time penalty of extending the full coherent integration period.
3Reliability
If block averaging is performed to reduce noise power, then signal-to-noise ratio is improved, but processing complexity is increased
Solution Approach 1:
The patent segments the signal into multiple blocks that can be processed independently through averaging. This segmentation approach distributes the computational load and allows for efficient implementation using standard digital signal processing operations, managing processing complexity while achieving noise reduction.
Data Source
AI summary
A signal acquisition method and device. Positioning signals as received are divided into at least two groups and frequency compensation is performed on each group of positioning signals. Each frequency compensated group of positioning signals is divided into at least two signal blocks, and an averaging operation is performed on the signal blocks in each group of signals, so as to obtain block-averaged groups of positioning signals. An acquisition result is determined based on the block-averaged groups of positioning signals. Noise power of each block-averaged group of signals is reduced. Therefore, noise power of received positioning signals can be reduced. This may improve signal-to-noise ratio of received signals and acquisition sensitivity of a receiver. Therefore, acquisition success rate of weak signals is increased.