BOC Signal Correlation Integrity for Accurate PRN Peak Alignment

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Solution Overview

Problem

Conventional satellite navigation systems face challenges in accurately aligning the internally generated PRN signal with the received Binary Offset Carrier (BOC) signal, leading to errors in determining the geographic position due to the ambiguity of correlation peaks and polarity flips in the correlation function, especially in systems like Galileo which use BOC(1,1) signals.

Innovation Solution

A method and system that utilize a first correlator to generate a reference signal and a second correlator to produce an integrity correlation function, allowing for the determination of the offset of the reference signal relative to the received PRN signal by comparing the integrity correlation function with the first correlation function, thereby ensuring correct alignment and tracking of the BOC signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single correlator is used to generate the correlation function, then the device complexity is reduced, but the measurement precision deteriorates due to inability to determine correct peak alignment

Engineering Contradiction:

Improvecorrelator structureVSAvoidpeak alignment accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The single correlator is divided into two separate correlators: a first correlator that generates the correlation function and a second correlator that generates the integrity correlation function. This segmentation allows each correlator to perform a specific function, enabling accurate peak alignment determination while maintaining manageable device complexity through functional specialization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second correlator acts as an intermediary that generates the integrity correlation function, which serves as a verification mechanism for the first correlator's correlation function. This intermediary component provides the additional information needed to determine correct peak alignment without significantly increasing overall system complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If conventional correlation tracking is used, then the ease of operation is maintained, but the reliability deteriorates due to polarity flips and peak ambiguity

Engineering Contradiction:

Improvesignal tracking operationVSAvoidsignal alignment integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system uses the integrity correlation function from the second correlator as feedback to verify the correctness of the correlation function from the first correlator. By comparing the signs and magnitudes of both correlation functions, the system can detect polarity flips and peak ambiguities, providing feedback that enhances reliability while maintaining ease of operation through automatic detection and correction.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The second correlator performs preliminary verification by generating the integrity correlation function before final peak alignment is determined. This preliminary action allows the system to identify potential alignment errors early in the processing chain, preventing unreliable measurements from propagating through the tracking system.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the PRN signal timing is not precisely aligned, then the processing speed is maintained, but the manufacturing precision deteriorates in terms of positional accuracy

Engineering Contradiction:

Improvesignal processing speedVSAvoidgeographic position accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system replaces trial-and-error mechanical timing adjustment with a mathematical verification approach using two correlation functions. By using the integrity correlation function to verify peak alignment through sign and magnitude comparison, the system achieves precise timing alignment without slowing down the signal processing, thereby maintaining productivity while improving positional accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8295411B2Method and system for maintaining integrity of a binary offset carrier signal

Publication Date: 2012.10.23 TRIMBLE NAVIGATION LTD

AI summary

Embodiments of the present technology recite a method and system for maintaining integrity of a binary offset carrier (BOC) signal. In one embodiment, a first correlator is configured for multiplying a timing signal with an internally generated pseudo-random noise (PRN) signal to create a reference signal. The first correlator is further configured for combining the reference signal with a received PRN signal and outputting a first correlation function based upon the combining. A second correlator is configured for multiplying the internally generated PRN signal with the received PRN signal and for outputting an integrity correlation function. A comparison component is configured for determining the offset of the reference signal relative to the received PRN signal based upon a comparison of the integrity correlation function with the first correlation function.