Magnetometer Network Calibration via Magnetic Field Trajectory Reconstruction

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Solution Overview

Problem

Current calibration techniques for networks of magnetometers are complex, expensive, and fail to accurately determine the positions and orientations of magnetometers, leading to imprecise localization of magnetic objects.

Innovation Solution

A method involving a tool with known magnetic field sources is used to calibrate magnetometers by reconstructing the trajectory of the magnetic field sources, calculating attributes, and determining the location of magnetometers through comparison, allowing for precise calibration with minimal external equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional calibration techniques using grid of field generators and imaging systems are used, then magnetometer array calibration can be achieved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvemagnetometer positioning accuracyVSAvoidcalibration equipment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential calibration function from complex external equipment (field generators and imaging systems) and implements it using only the magnetometer array itself. By removing the need for external calibration equipment and using the magnetometers to detect each other's positions, the solution achieves calibration with minimal device complexity while maintaining measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The magnetometer array performs calibration on itself without requiring external calibration equipment. Each magnetometer detects the magnetic field signals from other magnetometers to determine their relative positions and orientations, enabling the system to self-calibrate using its own components rather than relying on complex external field generators and imaging systems.

Inventive Principle:
Principle #25Self-service

2Ease of manufacture

If manufacturing tolerances are used directly without calibration, then the process is simple, but the localization precision deteriorates due to accumulated errors

Engineering Contradiction:
Improveassembly simplicityVSAvoidlocalization accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent performs calibration as a preliminary action before using the magnetometer array for localization tasks. By determining the actual positions and orientations of magnetometers through mutual detection and applying correction factors in advance, the system eliminates the need for extremely tight manufacturing tolerances while ensuring high localization precision in subsequent operations.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If more external calibration equipment is added to improve accuracy, then measurement precision improves, but the cost and complexity increase

Engineering Contradiction:
Improvemagnetometer position accuracyVSAvoidcalibration equipment quantity
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The magnetometer array serves multiple functions: it performs both the calibration process and the actual localization tasks using the same hardware components. The magnetometers detect magnetic field signals from each other during calibration, and then use these calibrated parameters for localization, eliminating the need for separate calibration equipment and reducing overall system complexity and cost.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This method provides a simple, rapid, and cost-effective way to calibrate magnetometers, improving the precision of object localization by minimizing errors in magnetometer positioning and orientation without requiring heavy external equipment.

Implementation Method 1

tracking the movement of a moving magnetic object by means of a network of magnetometers

Methodology Applied
Scientific EffectMagnetic field detection: Magnetism

Data Source

PatentEP3556287B1Method of calibrating a magnetometer network
Publication Date: 2021.10.13 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3556287B1 patent drawingFigure 1~3
  • EP3556287B1 patent drawingFigure 4~5
  • EP3556287B1 patent drawing

AI summary

The invention relates to a method for calibrating a magnetometer array (C1, Ci) involving the movement of a magnet-carrying tool (10) over the array, and the resolution of an optimization problem to determine the location of the magnetometers in the array. This location minimizes, according to an optimization criterion, the difference between an actual attribute (D, m1, m2) of the magnet-carrying tool and an estimate of said attribute determined without knowledge of the movement, based on said location and measurements taken by the magnetometers in the array during the movement.