GNSS Receiver Null Zone Detection Using Signal Energy Loss Parameter

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Solution Overview

Problem

GNSS receivers experience significant measurement errors when in a null zone due to insufficient satellite signal strength, leading to signal tracking drift and inaccurate position fixing.

Innovation Solution

A method and system for calculating a signal energy loss parameter (ESL) using filtered and averaged correlator values, which compares the ESL to a predetermined threshold to process satellite signal measurements and mitigate signal nulls by weighting or discarding measurements, thereby maintaining alignment with satellite signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the GNSS receiver continues to track satellite signals in a null zone with insufficient signal strength, then the receiver maintains continuous tracking operation, but measurement errors increase significantly and position fixing becomes inaccurate

Engineering Contradiction:

Improvetracking continuityVSAvoidposition fixing accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary detection of signal null conditions by monitoring signal strength and tracking quality before bad measurements occur. When a null zone is detected, the system proactively adjusts tracking behavior and flags potential measurement errors, preventing inaccurate position fixes rather than reacting after errors occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors tracking quality metrics and signal strength, providing feedback to adjust tracking loop parameters and measurement processing. When signal strength drops below thresholds, the feedback mechanism triggers null zone detection and adjusts measurement weighting or discards measurements, maintaining accuracy despite continuous tracking operation.

Inventive Principle:

Principle #23Feedback

2Ease of operation

If the GNSS receiver uses tracking loops driven by random noise in a dead zone, then the receiver maintains operational state, but signal tracking drifts randomly and large measurement errors occur

Engineering Contradiction:

Improvereceiver operational stateVSAvoidsignal tracking accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts tracking loop parameters and measurement processing based on real-time signal quality assessment. When operating in dead zones with noise-driven tracking, the system modifies tracking bandwidth, adjusts measurement weighting factors, and implements adaptive thresholds to maintain operational state while minimizing the impact of random drift on measurement accuracy.

Inventive Principle:

Principle #15Dynamics

3Productivity

If the GNSS receiver processes measurements from satellites with weak signals, then the receiver maintains satellite signal tracking, but the position solution contains large errors

Engineering Contradiction:

Improvesatellite signal trackingVSAvoidposition solution accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system applies local quality control by assessing and weighting individual satellite measurements based on their specific signal strength and quality metrics. Rather than uniformly processing all satellite signals, the system identifies weak signal measurements and applies appropriate weighting or exclusion on a per-satellite basis, maintaining tracking of all satellites while filtering out measurements that would degrade position solution accuracy.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10094931B2Detection of, and processing of signals within a null zone by a global navigation satellite system receiver

Publication Date: 2018.10.09 SAMSUNG ELECTRONICS CO LTD

AI summary

Apparatuses, systems, and methods for mitigating the effects of null zones on the measurements of Global Navigation Satellite System (GNSS) receivers are described. In one aspect, a GNSS receiver calculates both a filtered value of an integrated and summed value for a punctual correlator of a satellite signal (“the calculated filtered punctual correlator value”) and an average of integrated and summed correlator values for a plurality of noise/offset correlators of the satellite signal (“the calculated average noise/offset correlator value”). The GNSS receiver then calculates a signal energy loss parameter ESL of the satellite signal using the calculated filtered punctual correlator value and the calculated average noise/offset correlator value and processes the satellite signal measurement based at least on the signal energy loss parameter ESL and a predetermined threshold ThSL presently corresponding to the punctual and noise/offset correlators of the satellite signal.