GNSS Signal Acquisition via Parallel Slice Processing
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Solution Overview
Problem
Global navigation satellite systems (GNSS) face challenges in acquiring signals due to severe signal-to-noise ratio degradation, especially in indoor environments or with strong interferences, requiring extensive search times and complex hardware, which increases cost and power consumption.
Innovation Solution
The method involves multiplying incoming signals with time-shifted spreading codes, converting to zero nominal frequency, filtering, and downsampling, followed by parallel concatenation of slices to determine signal power metrics and frequency offsets, allowing for faster acquisition and reduced hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a bank of correlators or Fast Fourier Transform is used to address the search problem, then acquisition speed is improved, but hardware complexity and cost increase
Solution Approach 1:
The patent divides the correlation process into multiple slices, where each slice processes a specific portion of the correlation space. This segmentation allows parallel processing of correlation operations without requiring a full bank of correlators, thus reducing hardware complexity while maintaining acquisition speed. Each slice independently processes correlation for specific code offset ranges, and results are combined to provide comprehensive search coverage.
2Reliability
If coherent integration time is increased to detect weaker signals, then signal detection capability is improved, but pre-detection bandwidth decreases requiring finer search resolution
Solution Approach 1:
The patent introduces a new dimension to the search process by processing correlation results in the frequency domain after time-domain correlation. By transforming the correlation output through Fast Fourier Transform and analyzing power spectral density, the system achieves fine frequency resolution without requiring excessively long coherent integration times. This dimensional transition allows simultaneous optimization of detection capability and search resolution.
Data Source
AI summary
Systems and methods for acquiring global navigation satellite system (GNSS) signals. An incoming signal is multiplied with a time shifted spreading code replica and converted to zero (or very low) nominal frequency. The converted signal is filtered and downsampled by a large scale. A signal power metric and frequency offset are then determined. This is performed over multiple slices. Fast acquisition is achieved by parallel concatenation of numerous slices.