Correlation Code Segmentation for Satellite Multipath Error Reduction

Solution Overview

Problem

Current satellite positioning systems face significant positioning errors due to multipath interference, where indirect satellite signals are received after reflection or diffraction, making it difficult to detect correlation peaks and thus affecting reception sensitivity.

Innovation Solution

A correlation processing method is introduced where the code value of the chip boundary period is set to a replica code value, and the code value of the chip center period is set to a predetermined value, such as zero or repetition of the replica code, to generate a correlation code for correlation calculations with received satellite signals, reducing multipath influence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a part of the replica code is set to invalid values (zero) to reduce multipath influence, then positioning error due to multipath is reduced, but the correlation value becomes small making peak detection difficult and reception sensitivity deteriorates

Engineering Contradiction:

Improvepositioning accuracyVSAvoidreception sensitivity

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The code is divided into multiple segments: valid code portions (used for correlation calculation) and invalid code portions (set to zero to eliminate multipath influence). This segmentation allows the system to selectively process different parts of the code based on their utility for positioning versus their susceptibility to multipath interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the code are assigned different properties: some portions retain their original replica code values for maintaining correlation strength, while other portions are set to zero for reducing multipath interference. This local differentiation optimizes both positioning accuracy and reception sensitivity in different code regions.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If the correlation value is reduced to eliminate multipath influence, then positioning error is reduced, but it becomes difficult to detect the peak of the correlation value

Engineering Contradiction:

Improvepositioning accuracyVSAvoidpeak detection difficulty

Core Design Contradiction:

Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The code is divided into multiple segments: valid code portions (used for correlation calculation) and invalid code portions (set to zero to eliminate multipath influence). This segmentation allows the system to selectively process different parts of the code based on their utility for positioning versus their susceptibility to multipath interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the code are assigned different properties: some portions retain their original replica code values for maintaining correlation strength, while other portions are set to zero for reducing multipath interference. This local differentiation optimizes both positioning accuracy and reception sensitivity in different code regions.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10101463B2Correlation processing method, correlation processing circuit

Publication Date: 2018.10.16 SEIKO EPSON CORP

AI summary

A correlation processing method includes generating a correlation code in which a code value of a chip boundary period is set to a value of a replica code, and a code value of a chip center period other than the chip boundary period is set to a predetermined value, and performing a correlation calculation with respect to the correlation code and a received code signal obtained by demodulating a received signal from a positioning satellite.