GNSS Inaccuracy Detection for Urban Vehicle Safety

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Solution Overview

Problem

GNSS and GPS systems experience reduced accuracy in urban environments due to poor clear sky views and high multi-path radio frequency signal environments, leading to inaccuracies in position data, which can impact vehicle-to-vehicle and vehicle-to-infrastructure safety technologies.

Innovation Solution

A system that includes a GNSS or GPS receiver, an average position and standard deviation determination unit, and an inaccuracy determination unit, which assesses the standard deviation of vehicle position data to adjust safety applications and update Basic Safety Messages (BSM) for remote vehicles, ensuring accurate position information is communicated through a dedicated short-range communication system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GNSS/GPS receivers are used in urban environments, then vehicle position information can be obtained, but the position accuracy deteriorates due to poor clear sky view and multi-path RF signals

Engineering Contradiction:

Improveposition accuracyVSAvoidmulti-path RF signals and poor clear sky view

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system continuously monitors position data from multiple sources (GNSS/GPS, cellular towers, Wi-Fi access points) and compares expected versus actual positions. When discrepancies exceed thresholds, the system adjusts safety application confidence levels and triggers recalibration, creating a closed-loop feedback mechanism that adapts to urban signal conditions

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces intermediate positioning methods (cellular tower triangulation, Wi-Fi access point positioning) as mediators when GNSS/GPS signals are unreliable. These alternative positioning systems serve as intermediaries to provide position information when direct satellite signals are blocked or reflected by urban structures

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If V2X safety applications rely on GNSS/GPS data, then vehicle safety can be improved, but false warnings increase due to inaccurate position data in urban environments

Engineering Contradiction:

ImproveV2X safety application reliabilityVSAvoidfalse warnings

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system applies partial action by adjusting confidence levels rather than completely disabling safety applications. When position accuracy is questionable, the system reduces confidence in position-dependent safety features while maintaining other safety functions, allowing operation with degraded rather than eliminated capability

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent dynamically changes operational parameters (confidence thresholds, safety application activation criteria) based on measured position accuracy. When urban signal conditions degrade position accuracy, the system adjusts parameters to account for the reduced precision, preventing false warnings while maintaining safety functionality

Inventive Principle:

Principle #35Parameter changes

3Loss of information

If standard GNSS/GPS accuracy parameters are used, then position information can be provided, but the accuracy indication does not reflect actual performance in urban environments

Engineering Contradiction:

Improveaccurate position accuracy informationVSAvoidreported accuracy vs. actual accuracy

Core Design Contradiction:

Loss of informationVSMeasurement precision

Solution Approach 1:

The system performs preliminary validation of GNSS/GPS accuracy by comparing position data against known reference points and alternative positioning methods before trusting the reported accuracy. This preliminary check occurs continuously, preparing the system to detect when reported accuracy does not match actual performance

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback loops that continuously monitor the consistency between reported GNSS/GPS accuracy and actual position reliability. When discrepancies are detected, the system adjusts the confidence level and switches to alternative positioning methods, creating a self-correcting mechanism that maintains accurate position information

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10401179B2GNSS and GPS inaccuracy detection method for urban environments

Publication Date: 2019.09.03 DENSO INTERNATIONAL AMERICA INC

AI summary

A system for detecting inaccuracies in a global network satellite system receiver or a global positioning system receiver within a vehicle includes a global network satellite system receiver or a global positioning system receiver, an average position and standard deviation determination unit, an inaccuracy determination unit, and a vehicle controller. The global network satellite system receiver or global positioning system receiver receives a signal indicating a current position of a vehicle. The average position and standard deviation determination unit determines an average position and a standard deviation for a position of the vehicle. The inaccuracy determination unit determines whether the standard deviation for the position is greater than a standard deviation threshold. The vehicle controller adjusts safety applications of one of the vehicle or a remote vehicle if the standard deviation for the position is greater than the standard deviation threshold.