Proactive Positioning Switch for Urban Canyon Accuracy

Solution Overview

Problem

GNSS positioning accuracy deteriorates in urban canyon environments and is unreliable in areas like tunnels or under elevated bridges, leading to low absolute position measurement accuracy, even when relative displacement measurement is high.

Innovation Solution

A position measurement apparatus that proactively switches between GNSS-based absolute positioning and inertial/relative displacement measurement units, using a pre-determined or dynamically created plan based on GNSS signal quality and accuracy indices, to ensure accurate positioning even in areas with poor or no GNSS reception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reactive switching between GNSS positioning and inertial positioning is performed based on GNSS signal reception quality, then positioning can be maintained in poor reception areas, but the measurement accuracy of absolute position is lowered because switching occurs only after degradation

Engineering Contradiction:

Improvepositioning availabilityVSAvoidabsolute position accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by proactively switching to inertial positioning before GNSS signal degradation occurs. This is achieved by predicting future GNSS reception quality based on current signal characteristics and environmental data, then pre-switching to the inertial positioning system to maintain absolute position accuracy throughout tunnel passages and urban canyon areas.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements dynamic switching between positioning modes based on real-time GNSS signal quality assessment and predicted reception conditions. The switching decision is not static but adapts continuously to changing environmental conditions, allowing the system to optimize between GNSS and inertial positioning dynamically throughout the mobile object's trajectory.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If GNSS-based absolute positioning is used in urban canyon environments or tunnels, then absolute position can be obtained, but positioning accuracy significantly deteriorates due to signal blockage or poor reception quality

Engineering Contradiction:

Improveabsolute position accuracyVSAvoidpositioning availability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary action by proactively switching to inertial positioning before GNSS signal degradation occurs. This is achieved by predicting future GNSS reception quality based on current signal characteristics and environmental data, then pre-switching to the inertial positioning system to maintain absolute position accuracy throughout tunnel passages and urban canyon areas.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system introduces an intermediary mechanism by using predicted GNSS reception quality as an intermediate indicator to trigger proactive switching. Rather than directly responding to degraded signals, the system uses prediction of future signal quality as a mediator to initiate switching to inertial positioning in advance, ensuring continuous accurate positioning.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If only inertial positioning is used to maintain positioning in GNSS-denied areas, then positioning availability is maintained, but absolute position accuracy degrades over time due to error accumulation

Engineering Contradiction:

Improvepositioning availabilityVSAvoidabsolute position accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by proactively switching to inertial positioning before GNSS signal degradation occurs. This is achieved by predicting future GNSS reception quality based on current signal characteristics and environmental data, then pre-switching to the inertial positioning system to maintain absolute position accuracy throughout tunnel passages and urban canyon areas.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring GNSS signal quality and using this information to control switching decisions. The feedback loop assesses current and predicted GNSS reception conditions, then adjusts the positioning mode accordingly, ensuring the system transitions to inertial positioning when GNSS quality deteriorates and can return when conditions improve.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12105212B2Position measurement apparatus, position measurement method and program

Publication Date: 2024.10.01 NT T INC

AI summary

A position measurement apparatus for measuring an absolute position of a mobile object, the position measurement apparatus includes one or more computers each including a memory and a processor configured to measure the absolute position of the mobile object based on signals transmitted from navigation satellites; measure a displacement of the mobile object from a certain position; and switching between measuring the absolute position of the mobile object and measuring the displacement of the mobile object from the certain position in accordance with a plan which is created in advance or created during movement of the mobile object.