GNSS Ranging Code Correlation Detection via Interpolation
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Solution Overview
Problem
Existing GNSS receivers face complexity and power consumption issues due to the need for high sampling rates to accurately detect ranging code correlation functions, which results in large silicon area requirements and significant power usage.
Innovation Solution
A ranging code correlation function detection system that correlates digitized GNSS signals with ranging codes at multiple offsets and uses an interpolation filter to generate estimated correlation points between existing data points, allowing for accurate code delay estimation at lower sampling rates, thereby reducing hardware complexity and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sampling rates are used to accurately detect ranging code correlation functions, then measurement precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent segments the correlation function detection process into two stages: first performing correlation at discrete sample points, then applying interpolation to estimate values between samples. This segmentation allows accurate code delay identification without requiring continuously high sampling rates across the entire system, thereby reducing hardware complexity while maintaining measurement precision.
Solution Approach 2:
The patent transitions from a one-dimensional approach (direct high-rate sampling) to a two-dimensional approach by introducing the interpolation dimension. Correlation values are computed at discrete points, then interpolation in the time domain generates estimated values between points, effectively adding a computational dimension that reduces the need for high sampling rates and associated hardware complexity.
2Measurement precision
If high sampling rates are used to accurately detect ranging code correlation functions, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent segments the signal processing into discrete correlation operations at sampled points followed by interpolation. This segmentation allows the system to perform computationally intensive correlation only at discrete intervals rather than continuously at high rates, significantly reducing power consumption while maintaining accurate code delay identification through the interpolation step.
Solution Approach 2:
The patent replaces the mechanical approach of increasing sampling rate (which directly increases power consumption) with a computational substitution using interpolation algorithms. This substitution maintains measurement precision by mathematically estimating intermediate correlation values, thereby achieving accurate code delay identification without the proportional power consumption increase that would result from actual high-rate sampling.
3Measurement precision
If high sampling rates are used to accurately detect ranging code correlation functions, then measurement precision is improved, but silicon area increases
Solution Approach 1:
The patent segments the correlation detection into discrete sample point operations followed by interpolation processing. This segmentation reduces silicon area requirements by eliminating the need for high-speed correlators that would be required for continuous high-rate sampling, while maintaining measurement precision through the interpolation step that computes intermediate correlation values with reduced hardware demands.
Solution Approach 2:
The patent introduces an interpolation dimension that allows accurate code delay identification without requiring the physical hardware infrastructure of high sampling rates. By computing correlation at discrete points and then interpolating in the time domain, the system achieves the same measurement precision as high-rate sampling would provide, but with significantly reduced silicon area for the correlator and associated high-speed processing circuitry.
Data Source
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AI summary
A ranging code correlation function detection system (304) for use in a global navigation satellite system "GNSS" receiver (300) that includes: a correlation block (320) to correlate a digitized GNSS signal (e.g. at or above a critical sampling rate) with a corresponding ranging code at each of a plurality of different offsets from a current estimate of a code delay to generate a plurality of correlation data points; an interpolation filter (322) configured to generate at least one estimated correlation data point that lies between two of the correlation data points based on the current estimate of the code delay. In some cases the ranging code correlation function detection system may also include a discriminator block (324) configured to generate an updated estimate of the code delay based on the at least one estimated correlation data point.