Vehicle Authorization Using Angle-Resolving Magnetic Field Sensors

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Solution Overview

Problem

Existing methods for authorizing the use of motor vehicles lack effective protection against manipulation, particularly tampering with signals used for authorization.

Innovation Solution

A method utilizing two spatially spaced antennas and an angle-resolving magnetic field sensor to determine the spatial components of electromagnetic fields, combined with a motion sensor to detect movement and prevent unauthorized signal transmission, ensuring the angle between signals exceeds a threshold for valid authorization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single antenna is used for authorization, then the device complexity is reduced, but the protection against manipulation is insufficient

Engineering Contradiction:
Improveprotection against manipulationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system divides the single antenna function into multiple spatially separated antennas (first antenna and second antenna). Each antenna independently transmits signals and the system evaluates multiple signal paths to determine authorization, thereby increasing security against manipulation while maintaining manageable system complexity through modular architecture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an angle-resolving magnetic field sensor as an intermediary component that measures the spatial relationship between antennas and identifier. This sensor acts as a mediator to verify the geometric configuration of signal transmission, adding a layer of manipulation detection without significantly increasing overall system complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If signal transmission is allowed without movement detection, then the ease of operation is improved, but the security against unauthorized access is reduced

Engineering Contradiction:
Improvesecurity against unauthorized accessVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system dynamically evaluates authorization based on real-time movement detection. The motion sensor continuously monitors for movement, and authorization is granted only when movement is detected, creating a dynamic security mechanism that adapts to user behavior patterns while maintaining ease of legitimate operation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The motion sensor performs preliminary detection of movement before authorization is granted. By checking for movement in advance of the authorization decision, the system ensures that only legitimate users who physically approach the vehicle can gain access, preventing unauthorized remote activation while maintaining smooth operation for legitimate users

Inventive Principle:
Principle #10Preliminary action

3Reliability

If repeaters are used to extend signal range, then the communication range is increased, but the angle information is lost and manipulation becomes possible

Engineering Contradiction:
Improvedetection of parallelismVSAvoidsignal transmission range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces electromagnetic signal-based position determination with a magnetic field sensing mechanism. The angle-resolving magnetic field sensor directly measures the spatial configuration of antennas through magnetic field interactions, providing robust angle information that cannot be spoofed by signal repeaters, thereby maintaining reliability while allowing flexible signal transmission

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

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

Enhances security by preventing manipulation of radio links and ensuring only valid movements trigger authorization signals, thereby improving protection against tampering.

Implementation Method 1

the identification transmitter determines at least one of the spatial components of the first electromagnetic field of the received first signal, preferably using an angle-resolving magnetic field sensor

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

the identification transmitter is or will be provided with a motion sensor. The motion sensor determines whether it or the ID transmitter is being moved

Methodology Applied
Scientific EffectMotion sensing: Accelerometer

Implementation Method 3

the first vehicle antenna emits a first signal, which is received by the ID transmitter antenna

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 4

the first vehicle antenna emits a first signal, which is received by the ID transmitter antenna

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3433140B1Authorizing the use of a motor vehicle
Publication Date: 2021.03.31 BAYERISCHE MOTOREN WERKE AG

AI summary

The invention relates to a method for authorizing the use of a motor vehicle, which has at least one first and one second antenna, wherein the antennae are spaced apart from each other, by means of a portable identification transmitter, which has an identification transmitter antenna. The first vehicle antenna sends out a first signal, which is received by the identification transmitter antenna. The identification transmitter identifies one of the spatial components of the first electromagnetic field of the received first signal. The second vehicle antenna transmits a second signal that is received by the identification transmitter antenna. The identification transmitter identifies one of the spatial components of the second electromagnetic field of the received second signal. The identification transmitter transfers the data to the vehicle. A computer determines the angle between the spatial components and the vehicle provides an authorization signal if the determined angle exceeds a predetermined threshold value.