PEPS Nomadic Device Walking Detection via Magnetic Field Sensing

Solution Overview

Problem

Passive entry and passive start (PEPS) systems face issues with energy drain due to frequent activation signals, leading to battery depletion in nomadic devices and vehicles, and the 'wall effect' of delayed door unlocking when relying on manual wake-up actions.

Innovation Solution

A nomadic device equipped with a magnetic field sensor and processor that detects changes in the Earth's magnetic field to emit an activation signal only when the operator is walking, minimizing unnecessary energy consumption and optimizing communication range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the vehicle or nomadic device emits interrogation/activation signals at regular intervals, then the PEPS system wake-up is improved, but energy drain on vehicle or nomadic device battery worsens

Engineering Contradiction:

ImprovePEPS system wake-upVSAvoidvehicle battery

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent replaces the traditional electromagnetic signal-based wake-up mechanism with a magnetic field sensing mechanism. The nomadic device detects changes in the Earth's magnetic field caused by the operator's walking motion, triggering the activation signal only when walking is detected. This substitution eliminates the need for continuous signal transmission while maintaining reliable wake-up functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The nomadic device utilizes the operator's natural walking motion to generate the trigger signal for activation. The magnetic field sensor detects the characteristic magnetic disturbances caused by human movement, and the processor interprets these patterns to automatically initiate communication with the vehicle. This self-service approach eliminates the need for external wake-up signals or manual user actions.

Inventive Principle:

Principle #25Self-service

2Reliability

If the vehicle or nomadic device emits interrogation/activation signals at regular intervals, then the PEPS system wake-up is improved, but energy drain on nomadic device battery worsens

Engineering Contradiction:

ImprovePEPS system wake-upVSAvoidnomadic device battery

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the traditional electromagnetic signal-based wake-up mechanism with a magnetic field sensing mechanism. The nomadic device detects changes in the Earth's magnetic field caused by the operator's walking motion, triggering the activation signal only when walking is detected. This substitution eliminates the need for continuous signal transmission while maintaining reliable wake-up functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of continuous or frequent periodic signal transmission, the system uses periodic detection of magnetic field changes caused by walking motion. The magnetic field sensor continuously monitors for characteristic patterns of human movement, and the processor triggers activation signals only when these periodic walking patterns are detected, significantly reducing energy consumption compared to fixed-interval signal transmission.

Inventive Principle:

Principle #19Periodic action

3Use of energy by stationary object

If manual wake-up action is used, then energy consumption is reduced, but door unlocking delay worsens due to wall effect

Engineering Contradiction:

Improvevehicle batteryVSAvoiddoor unlocking delay

Core Design Contradiction:

Use of energy by stationary objectVSLoss of time

Solution Approach 1:

The nomadic device utilizes the operator's natural walking motion to generate the trigger signal for activation. The magnetic field sensor detects the characteristic magnetic disturbances caused by human movement, and the processor interprets these patterns to automatically initiate communication with the vehicle. This self-service approach eliminates the need for external wake-up signals or manual user actions.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system performs preliminary detection of the operator's approach through magnetic field sensing before the operator reaches the vehicle. By detecting the characteristic magnetic field changes caused by walking motion at a distance, the system can initiate the wake-up and authentication sequence in advance, eliminating the wall effect delay that occurs with manual wake-up actions at the door.

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 solution enhances battery life by reducing unnecessary signal transmissions and improves security by ensuring communication only when the operator is approaching the vehicle, thereby minimizing energy drain and enhancing security.

Implementation Method 1

The nomadic device is configured to detect a change of a magnetic field relative to the nomadic device

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS8965599B2Passive entry and passive start system with operator walking detection

Publication Date: 2015.02.24 APTIV TECHNOLOGIES AG

AI summary

A passive entry passive start (PEPS) vehicle security system configured to activate a vehicle function when an activation signal is received. The system includes a nomadic device configured to detect a change of a magnetic field relative to the nomadic device, and emit an activation signal only if the change corresponds to walking by an operator carrying the nomadic device.