CBOC Signal Correlation Function Side-Peak Removal

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Solution Overview

Problem

Existing methods for signal synchronization in global navigation satellite systems (GNSS) face challenges in accurately removing side-peaks from the autocorrelation function of CBOC signals, leading to position errors in multipath environments, particularly for CBOC(6,1,1/11) signals used in next-generation satellite navigation systems like Galileo and GPS III.

Innovation Solution

A method is developed to generate an unambiguous correlation function by receiving and interpreting the CBOC(6,1,1/11) signal, combining partial correlation functions, and weighted-combining them to remove side-peaks, effectively using the subcarrier pulse period of BOCsin(6,1) to enhance synchronization robustness in multipath channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the autocorrelation function of CBOC signals is used directly for synchronization, then the method is simple, but side-peaks remain causing position errors in multipath environments

Engineering Contradiction:

Improvesimplicity of synchronization methodVSAvoidsynchronization accuracy in multipath environments

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the autocorrelation function into multiple partial correlation functions (R0, R1, R2, R3, R4, R5) corresponding to different subcarrier pulse periods. Each partial correlation function is processed separately through absolute value operations and combinations, allowing selective removal of side-peaks while preserving main peak characteristics for accurate synchronization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts and removes the harmful side-peaks from the autocorrelation function by identifying them through the partial correlation functions and applying absolute value operations. The side-peaks are eliminated through the combination formula: Rm = |Sm(τ)| + |S11-m(τ)| - |Sm(τ) - S11-m(τ)|, which extracts only the main peak components while discarding side-lobe interference.

Inventive Principle:

Principle #2Taking out (Extraction)

2Measurement precision

If side-peaks are removed from the correlation function, then synchronization accuracy improves, but the complexity of the correlation function generation increases

Engineering Contradiction:

Improvesynchronization precisionVSAvoidcomplexity of correlation function generation

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The complex task of side-peak removal is segmented into manageable steps: first computing the autocorrelation function, then dividing it into 6 partial correlation functions based on subcarrier pulse periods, processing each partially, and finally combining them. This segmentation makes the complex operation more systematic and implementable.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent merges the results of multiple partial correlation functions through a systematic combination process. The absolute value operations and weighted combinations of partial correlation functions (R0 through R5) are merged to produce the final unambiguous correlation function, achieving side-peak removal while maintaining computational efficiency.

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If CBOC signals are used for next-generation GNSS, then multipath resistance improves, but existing synchronization methods fail to accurately remove side-peaks leading to position errors

Engineering Contradiction:

Improvemultipath resistanceVSAvoidposition accuracy

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies local quality by treating different components of the correlation function differently. Each partial correlation function corresponds to a specific subcarrier pulse period and is processed with appropriate absolute value operations tailored to its characteristics. This localized processing ensures that side-peaks are removed while preserving the unique multipath-resistant properties of CBOC signals.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the harmful side-peaks in the autocorrelation function into beneficial information by using absolute value operations and combinations. The side-peaks, which previously caused position errors, are transformed through the partial correlation function processing into components that can be selectively removed, leaving only the main peak for accurate position determination.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS9454512B2Method of generating correlation function, method of tracking signal and signal tracking system

Publication Date: 2016.09.27 RES & BUSINESS FOUND SUNGKYUNKWAN UNIV

AI summary

A method of generating a correlation function, a method of tracking a signal, and a signal tracking apparatus are provided. The method of generating a correlation function involves receiving a CBOC(6,1,1/11) signal, interpreting a subcarrier pulse period of the CBOC(6,1,1/11) signal as a subcarrier pulse period of BOCsin(6,1), combining partial correlation functions constituting an autocorrelation function of CBOC(6,1,1/11) to generate a correlation function, and weighted-combining the correlation function to generate an unambiguous correlation function.