Magnetic Positioning Anomaly Detection via Motion Sensor Fusion

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Solution Overview

Problem

Magnetic location devices face precision loss due to disturbances, and existing anomaly detection methods rely solely on magnetic data, which can be unreliable.

Innovation Solution

The method employs motion sensors, such as accelerometers, to measure inclination data independent of magnetic fields, combining it with magnetic localization data to detect anomalies by determining orientation parameters and comparing these with inertial data to identify errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If magnetic field data is used for anomaly detection, then the detection method is simple and consistent with the magnetic localization system, but the detection accuracy deteriorates when disturbing objects are present in the magnetic field

Engineering Contradiction:
Improveanomaly detection system complexityVSAvoidanomaly detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces motion sensors as an intermediary measurement system that indirectly detects anomalies by comparing expected motion behavior with actual motion behavior, rather than directly measuring magnetic field disturbances. This mediator approach allows anomaly detection without being affected by magnetic field disruptions from disturbing objects.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the magnetic field-based detection system with a motion-based detection system. Instead of analyzing magnetic field perturbations caused by disturbing objects, the system uses motion sensors to track the actual movement of the magnetic locator and compares it with expected motion, substituting magnetic measurement with mechanical motion measurement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If motion sensors are added to the magnetic localization system, then the anomaly detection accuracy improves, but the device complexity increases

Engineering Contradiction:
Improveanomaly detection accuracyVSAvoidlocalization system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The motion sensors serve multiple functions: they track the actual motion of the magnetic locator for navigation purposes and simultaneously enable anomaly detection by comparing expected versus actual motion. This multi-functionality reduces the need for separate dedicated anomaly detection hardware, thereby limiting the increase in overall system complexity.

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

Solution Approach 2:

The system uses feedback from motion sensors to continuously monitor and detect anomalies. The motion data provides real-time feedback about the locator's actual position and orientation, which is compared with expected values to identify disturbances, creating a self-monitoring mechanism that improves detection accuracy without requiring complex external monitoring systems.

Inventive Principle:
Principle #23Feedback

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 approach enhances anomaly detection accuracy, providing rapid and precise identification of errors, improving the reliability of magnetic localization systems, especially in sensitive applications like medical precision tracking.

Implementation Method 1

The magnetic receiver measures the magnetic field emitted by the magnetic transmitter in order to determine the orientation and/or positioning of the magnetic transmitter

Methodology Applied
Scientific EffectMagnetic field emission and measurement: Magnetic Field

Implementation Method 2

a first motion sensor (5) capable of determining, in particular by measurement, a first data point (g1) dependent on the inclination of the first object (3) in a base frame, in particular the Earth's frame of reference

Methodology Applied
Scientific EffectGravitation or inertial measurement: Gravitation

Data Source

PatentEP3427088B1Method for detecting an anomaly in the context of using a magnetic positioning device
Publication Date: 2023.07.26 MINMAXMEDICAL
  • EP3427088B1 patent drawingFigure 1~2
  • EP3427088B1 patent drawingFigure 3~4
  • EP3427088B1 patent drawing

AI summary

The invention relates to a method for detecting an anomaly, associated with a magnetic positioning device including a first magnetic element (1) and a second magnetic element (2) associated with a first object (3) and a second object (4), respectively, characterised in that the first object (3) comprises a first motion sensor (5) capable of determining a first data item (g1) which is dependent on the tilt of the first object (3) in a basic frame of reference, in particular the earth's frame of reference, and in that the method comprises: a step of determining (E1) the first data item (g1) from said first motion sensor (5); a step of determining (E2) a second data item (g2) which is dependent on the tilt of the second object (4) in said basic frame of reference; a step of determining (E3) at least one orientation parameter by the magnetic positioning device using the first and second magnetic elements (1, 2); and a step of using (E4) said at least one orientation parameter and first and second data (g1, g2) to produce an indicator of the presence of the anomaly.