Underground Positioning via Magnetic Beacons

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Solution Overview

Problem

Conventional GPS systems are ineffective for determining the location of objects and personnel within underground facilities due to challenges in signaling and electromagnetic propagation complexities, limiting their accuracy and effectiveness.

Innovation Solution

A positioning system utilizing multiple surface transmitters as magnetic beacons, combined with software-defined radio receivers and inertial guidance, to determine three-dimensional location both above and below ground, incorporating signals of opportunity and additional sensors for enhanced accuracy and communication capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional GPS systems are used for underground positioning, then satellite signals can be received above ground, but electromagnetic propagation fails in underground environments

Engineering Contradiction:

Improvepositioning reliabilityVSAvoidelectromagnetic propagation blockage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces magnetic field beacons as an intermediary medium for positioning. Instead of relying on satellite signals that cannot penetrate underground, the system uses magnetic field beacons deployed in or near the underground facility that emit magnetic fields capable of penetrating the underground environment, allowing the receiver to determine position through magnetic field measurements

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the electromagnetic wave-based GPS system with a magnetic field-based positioning system. By substituting the propagation mechanism from radio waves to magnetic fields, the system overcomes the blockage problem in underground environments where electromagnetic waves cannot effectively propagate

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If very low frequency communication systems are used underground, then communication capability is achieved, but positioning accuracy is limited to 2-5%

Engineering Contradiction:

Improvecommunication capabilityVSAvoidpositioning accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the positioning function from the communication function. While very low frequency systems provide communication capability, the positioning function is achieved through a separate magnetic field beacon system with receivers that measure magnetic field vectors, achieving much higher positioning accuracy independent of the communication system's limitations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The magnetic field beacon system serves multiple functions: it provides both positioning information through vector measurements and can support communication operations. The same magnetic field infrastructure enables both high-accuracy positioning and operational communication in the underground environment

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If multiple surface transmitters are deployed as magnetic beacons, then three-dimensional location determination is enabled, but system complexity increases

Engineering Contradiction:

Improvethree-dimensional location accuracyVSAvoidsystem configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple magnetic field beacons into a unified positioning system where the receivers process signals from multiple beacons simultaneously. By merging the information from multiple transmitters through vector measurements and triangulation algorithms, the system achieves three-dimensional positioning capability while managing complexity through integrated signal processing

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate three-dimensional location determination and low-data-rate communication in underground environments, providing a practical solution for navigation and surveying both above and below ground, with improved accuracy and applicability to various geologies.

Implementation Method 1

The systems only obtain a shallow depth position when the communication system is used underground... The positioning system finds the location of an object by applying theoretical calculations, scale model testing, and technology demonstrations including state-of-the-art signal processing

Methodology Applied

Scientific EffectElectromagnetic propagation: Electromagnetic Induction

Implementation Method 2

The software defined radio receiver carried underground can accurately measure the angles between the various transmitters (vectors pointing back along magnetic field lines to the surface beacons)

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS8018382B2Positioning system and method

Publication Date: 2011.09.13 RAYTHEON CO

AI summary

A positioning system designed to provide a three dimensional location of an object. The system can include one or more multiple transmitters or electromagnetic beacons, software defined radio receivers with an associated processing unit and data acquisition system, and magnetic antennas. The system applies theoretical calculations, scale model testing, signal processing, and sensor data to operate.