Magnetic Relative Positioning Using Modulated Multi-Coil Fields

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Solution Overview

Problem

Existing systems for precise position determination of objects, such as drones or robots, face challenges in achieving high accuracy, cost-effectiveness, and efficient power consumption, especially in outdoor environments.

Innovation Solution

A method using a magnetic field generation device to create three directed magnetic fields with distinct modulation frequencies, which are recorded by a magnetic field recording device to determine the relative position of an object with respect to a reference object.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If satellite-based navigation systems are used for positioning, then positioning accuracy is improved (a few meters to less than 50 cm), but the system is limited to outdoor areas only

Engineering Contradiction:
Improvepositioning accuracyVSAvoidenvironmental adaptability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces magnetic fields as an intermediary medium for position determination. Instead of relying on satellite signals that only work outdoors, the system uses magnetic field emitters and detectors to create a positioning mechanism that works indoors and outdoors, thus resolving the environmental limitation while maintaining positioning accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the satellite-based electromagnetic navigation system with a magnetic field-based positioning system. This substitution enables positioning functionality to work in environments where satellite signals are unavailable, thereby improving environmental adaptability while maintaining measurement precision

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

2Measurement precision

If radar-, video-, or lidar-based positioning systems are used, then positioning accuracy is improved, but the cost and computing power requirements increase significantly

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsystem cost and computing requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs relatively simple magnetic field emitters and detectors instead of expensive radar, video, or lidar systems. These magnetic field-based components are more cost-effective and require less computing power while still achieving the necessary positioning accuracy for applications like robotic lawnmowers

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes complex optical and electromagnetic sensing systems (radar, video, lidar) with a simpler magnetic field-based positioning system. This substitution reduces both the hardware cost and the computational requirements for processing positioning data

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

3Ease of manufacture

If magnetic field-based positioning systems are used, then cost is reduced, but positioning accuracy deteriorates compared to radar/lidar systems

Engineering Contradiction:
Improvesystem costVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent improves magnetic field positioning accuracy by using multiple emitters (at least three) with distinguishable modulation frequencies. This allows the system to determine both position and orientation accurately through signal processing, achieving precision sufficient for applications requiring less than 5 cm accuracy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent divides the positioning function into multiple magnetic field emitters, each transmitting at different modulation frequencies. This segmentation allows the receiving device to extract positional and orientational information through frequency-based signal differentiation, thereby improving measurement precision

Inventive Principle:
Principle #1Segmentation

4Measurement precision

If three directed magnetic fields with distinguishable modulation frequencies are generated, then position and orientation determination accuracy is improved, but the complexity of the magnetic field generating device increases

Engineering Contradiction:
Improveposition and orientation accuracyVSAvoidmagnetic field generating device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes each magnetic field emitter capable of transmitting at different modulation frequencies, allowing a single emitter to contribute to multiple positioning calculations. This multi-functionality reduces the overall system complexity compared to having separate dedicated emitters for each function

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 approach allows for precise determination of an object's position and orientation with reduced costs and power consumption, while being adaptable to various environments and applications.

Implementation Method 1

Generating at least three directed magnetic fields B1, B2, B3 with distinguishable modulation frequencies f1, f2, f3 by means of a magnetic field generating device assigned to the reference object, wherein the magnetic field generating device comprises at least three emitter coils

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

detecting magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| and modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3 by means of a magnetic field detecting device of the first object

Methodology Applied
Scientific EffectMagnetic Field Detection: Magnetic Field

Data Source

PatentEP4176289B1Method for ascertaining a relative position p, and system
Publication Date: 2025.05.14 ROBERT BOSCH GMBH
  • EP4176289B1 patent drawingFigure 1
  • EP4176289B1 patent drawingFigure 2
  • EP4176289B1 patent drawingFigure 3

AI summary

The method (10) according to the invention for ascertaining a relative position P of a first object (100, 100a, 100b) in relation to at least one reference object (200, 200a, 200b) has the steps of: - generating at least three oriented magnetic fields with distinguishable modulation frequencies using a magnetic field generating device (202) paired with the reference object (200, 200a, 200b), said magnetic field generating device (202) comprising at least three emitter coils which have a reciprocal defined arrangement relative to one another, - detecting magnetic field intensities and modulation frequencies of the magnetic fields using a magnetic field detection device (112, 112a) of the first object (100, 100a, 100b), and - ascertaining the relative position P of the first object (100, 100a, 100b) in relation to the at least one reference object (200, 200a, 200b) from the detected magnetic field intensities which can be paired with the oriented magnetic fields via the detected modulation frequencies using an analysis device (302). The invention additionally relates to a system comprising a first object, at least one reference object (200, 200a, 200b), and an analysis device (302), said system being designed to carry out the method (10) according to the invention.