Satellite Signal Arrival Time Estimation Using Dual Correlation
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Solution Overview
Problem
Current satellite positioning systems, particularly those using GNSS, face challenges in accurately determining the time of arrival of Binary Offset Carrier (BOC) signals due to high processing costs and complexity, especially in identifying the peak correlation output for precise time delay estimation.
Innovation Solution
A method involving the multiplication of incoming BOC signals by real-valued periodic modifying signals, such as sine and cosine-phased signals, to produce modified outputs that are correlated and compared, allowing for accurate time delay calculation using less processing power and simpler operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correlation operation is performed on BOC signal to identify ranging code, then signal arrival time can be determined, but processing complexity and cost increase significantly
Solution Approach 1:
The BOC signal processing is segmented into two separate correlation operations: one for the in-phase component and one for the quadrature component. This segmentation allows each correlation to operate on simplified signal representations, reducing the overall processing complexity while maintaining accurate time delay estimation through combination of both results
Solution Approach 2:
The patent introduces intermediate in-phase and quadrature correlation outputs as mediators between the raw BOC signal and the final time delay estimate. These intermediate results simplify the correlation process by breaking down the complex BOC signal into manageable components that can be processed more efficiently
2Measurement precision
If sampling time-step is reduced to reliably identify maximum correlation peak, then time of arrival estimation accuracy improves, but processing operations become more costly
Solution Approach 1:
The patent uses feedback from the in-phase and quadrature correlation outputs to determine the signal arrival time without requiring exhaustive fine-search sampling. The combined information from both correlation channels provides feedback that directly indicates the peak location, eliminating the need for progressively smaller sampling steps
Solution Approach 2:
Instead of performing complete correlation searches with very fine sampling steps, the patent applies partial action by using coarser sampling combined with the in-phase/quadrature correlation method. This approach achieves sufficient accuracy without the excessive processing operations that would result from exhaustive fine-grained sampling
3Device complexity
If single sideband method is used to simplify correlation, then processing complexity reduces, but time of arrival estimation accuracy deteriorates
Solution Approach 1:
The patent merges the in-phase and quadrature correlation results to achieve accurate time delay estimation. By combining the information from both correlation channels, the method recovers the precision needed for accurate arrival time determination while maintaining the processing simplicity of the single sideband approach
Solution Approach 2:
The solution creates a composite processing approach that combines elements of both full-signal correlation and single-sideband correlation. The in-phase and quadrature components are processed separately and then combined, creating a composite method that achieves the accuracy of full correlation with the simplicity of single-sideband processing
Data Source
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AI summary
The invention relates to a method of determining the time of arrival of an incoming satellite signal at a receiver, the method comprising: receiving an incoming signal, multiplying of the incoming signal by a first real-valued periodic modifying signal to produce a first modified output, correlating the first modified output to obtain a first correlation output, multiplying the incoming signal by a second real-valued periodic modifying signal to produce a second modified output, correlating the second modified output to produce a second correlation output and comparing the first correlation output with the second correlation output.