Underground Mobile Positioning with 3D Tunnel Z-Coordinate Resolution

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Solution Overview

Problem

Existing location tracking systems for underground mobile vehicles in mining and construction sites primarily provide 2D horizontal position information, which is not sufficient for accurately positioning vehicles in complex underground environments with overlapping tunnels and varying elevations, leading to ambiguity and inaccuracies.

Innovation Solution

A method using a three-dimensional tunnel model and a vertical plane ray cast operation to determine the z-coordinate of a mobile device's position based on received 2D position data and earlier resolved z-coordinate values, allowing for precise vertical positioning by selecting appropriate z-coordinates from sets associated with tunnel roofs or floors, even in cases of overlapping tunnels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If 2D horizontal position information is used for tracking mobile vehicles, then the positioning system is simple and easy to operate, but the positioning accuracy is insufficient in complex underground environments with overlapping tunnels and varying elevations

Engineering Contradiction:
Improvepositioning system operationVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transitions from 2D horizontal positioning to 3D positioning by adding the vertical dimension (z-coordinate). The system uses a three-dimensional tunnel model and performs vertical plane ray cast operations to determine z-coordinate values, enabling accurate positioning in overlapping tunnels with varying elevations while maintaining system operational simplicity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If 3D positioning with vertical plane ray cast operation is implemented, then positioning accuracy is improved in complex environments, but the computational complexity and processing requirements increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpositioning system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by pre-establishing a three-dimensional tunnel model and pre-defining vertical plane ray cast paths. The z-coordinate determination uses at least one earlier resolved z-coordinate value from preceding mobile device positions, reducing real-time computational complexity while maintaining high positioning accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a three-dimensional tunnel model as an intermediary between the mobile device and the positioning system. This model serves as a reference framework that simplifies the ray cast operations and z-coordinate determination process, making the overall system more manageable despite the increased precision requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If z-coordinate values are selected from sets associated with tunnel roofs or floors in overlapping tunnels, then vertical position ambiguity is resolved, but the selection process becomes more complex

Engineering Contradiction:
Improvepositioning reliabilityVSAvoidcoordinate selection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses feedback mechanisms by comparing the determined z-coordinate value with the mobile device's expected position and movement patterns. The selection of z-coordinate values from sets associated with tunnel roofs or floors is refined using at least one earlier resolved z-coordinate value, ensuring consistent and reliable positioning even in overlapping tunnel configurations.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3795798B1Positioning of mobile device in underground worksite
Publication Date: 2023.11.22 SANDVIK MINING & CONSTR OY
  • EP3795798B1 patent drawingFigure 1~2
  • EP3795798B1 patent drawingFigure 3a~4
  • EP3795798B1 patent drawingFigure 5a~5b

AI summary

According to an example aspect of the present invention, there is provided a method, comprising: receiving a three-dimensional tunnel model (410) of an underground tunnel system of a worksite, receiving two-dimensional position data (420) comprising sets of x coordinate values and y coordinate values of a mobile device in the underground tunnel system, performing a vertical plane ray cast operation (430) in the tunnel model at a mobile device position defined by an x coordinate value and an y coordinate value in the received position data, and determining a z coordinate value (440) for the mobile device position on the basis of the ray cast operation and at least one earlier resolved z coordinate value for a preceding mobile device position.