Mobile Device Magnetic Field Determination Using Orientation Correction

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Solution Overview

Problem

Mobile communication devices face inaccuracies and interference in magnetometer readings due to environmental and device-related factors, which affect the measurement of the Earth's magnetic field.

Innovation Solution

A method and system that determine location and orientation information using a mobile device, incorporating a magnetometer, accelerometer, and gyroscope to compute a magnetic field corresponding to the device's orientation, thereby simulating the Earth's magnetic field and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetometer readings are taken directly without correction, then the measurement process is simple, but the accuracy is reduced due to environmental interference and device components

Engineering Contradiction:
Improvemagnetic field measurement accuracyVSAvoidmeasurement process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by determining location information before obtaining magnetic field data, and by pre-computing the expected Earth's magnetic field based on location. This allows the system to compare actual readings with expected values and apply corrections accordingly, improving accuracy while managing complexity through structured preprocessing

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system introduces an intermediary computational process that acts as a mediator between the raw magnetometer readings and the final magnetic field determination. This intermediary layer applies corrections based on location data and orientation information, effectively filtering out interference from environmental factors and device components without requiring hardware modifications

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the mobile device operates in various environments, then the device has high adaptability, but magnetic interference from the environment and device components increases

Engineering Contradiction:
Improveoperational environment adaptabilityVSAvoidmagnetic interference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system determines location information and obtains magnetic field data for that specific location before taking measurements. By pre-fetching location-based magnetic field characteristics, the system can compensate for environmental variations and device-induced interference, maintaining accuracy across diverse operational environments

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes parameters by applying orientation information to transform magnetic field data from the device's coordinate system to the Earth's reference frame. This parameter transformation allows the system to account for device orientation and environmental factors, effectively separating the Earth's magnetic field from local interference regardless of the operating environment

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If orientation information is applied to magnetic field data, then the magnetic field determination accuracy is improved, but the computational complexity increases

Engineering Contradiction:
Improvemagnetic field determination accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system determines orientation information using accelerometer and gyroscope data before applying it to the magnetic field calculations. This preliminary determination of device orientation allows for proper coordinate transformation and correction of magnetic field readings, improving accuracy while organizing computations in a structured sequence that manages complexity

Inventive Principle:
Principle #10Preliminary action

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 provides accurate and robust magnetic field determination by accounting for device orientation and environmental factors, enhancing the reliability of magnetometer readings for navigation and other applications.

Implementation Method 1

A magnetometer is an instrument used to measure the strength and/or direction of the magnetic field in the vicinity of the instrument

Methodology Applied
Scientific EffectMagnetic field detection: Magnetometer

Implementation Method 2

The mobile device may also include a gyroscope for determining angular movement of the mobile device

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP2667153B1System and method for determining a magnetic field using a mobile device
Publication Date: 2015.04.01 BLACKBERRY LTD
  • EP2667153B1 patent drawingFigure 1
  • EP2667153B1 patent drawingFigure 2
  • EP2667153B1 patent drawingFigure 3

AI summary

A method and system are provided for determining a magnetic field using a mobile device. The method includes determining location information of the mobile device, obtaining magnetic field data based on the location information, determining orientation information of the mobile device and applying the orientation information to the magnetic field data to compute a magnetic field corresponding to the orientation of the mobile device.