Keyless Entry Device Noise-Resistant Distance Measurement

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Solution Overview

Problem

Smart keyless entry systems face issues with start-up signal discrimination due to noise interference from carried information devices, leading to erroneous distance measurement and control of vehicle doors.

Innovation Solution

The system employs a vehicle-side device transmitting a start-up signal at a first frequency and a portable device responding with a request signal at a second frequency, allowing periodic distance measurement without relying on start-up signals, and includes noise threshold checks to manage power consumption and reduce errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the vehicle-side device transmits a start-up signal to the portable device, then the portable device is started up to enable communication, but the start-up signal may be buried in noise signals from carried information devices and cannot be discriminated, leading to start-up failure

Engineering Contradiction:

Improvestart-up signal reception reliabilityVSAvoidnoise signal interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a request signal as an intermediary step between the start-up signal and the measurement signal. The portable device first receives the start-up signal, then actively transmits a request signal to the vehicle-side device, which in response transmits the measurement signal. This intermediary request signal mechanism ensures reliable communication initiation while avoiding the problem of the start-up signal being buried in noise from information devices.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the vehicle-side device transmits measurement signals periodically, then distance measurement is performed, but the portable device must be started up by the start-up signal each time, which is unreliable in noisy environments

Engineering Contradiction:

Improvedistance measurement accuracyVSAvoidportable device start-up reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by having the portable device start up once in response to the start-up signal, then actively requesting measurement signals at predetermined intervals. This eliminates the need for repeated start-up operations and allows reliable periodic distance measurement. The portable device's active request mechanism ensures measurement signals are received reliably without requiring repeated noisy start-up signal discrimination.

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If the portable device enters sleep mode between measurements, then power consumption is reduced, but the device must wake up reliably for each measurement cycle

Engineering Contradiction:

Improveportable device power consumptionVSAvoidwake-up signal reception reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements periodic action where the portable device enters sleep mode between measurements to conserve power, then wakes up at predetermined intervals to transmit request signals. The vehicle-side device responds with measurement signals at these same intervals. This periodic wake-up mechanism reduces power consumption while maintaining reliable distance measurement, as the device only needs to be active at specific predetermined times when it knows measurement signals will be transmitted.

Inventive Principle:

Principle #19Periodic 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 ensures reliable distance measurement and accurate control of vehicle doors even in noisy environments, reducing erroneous locking and unlocking due to noise interference from carried information devices.

Implementation Method 1

a vehicle-side device that is provided on the vehicle side and transmits a signal at a first frequency, and a portable device that is able to be carried by a user and transmits a signal at a second frequency

Methodology Applied

Scientific EffectElectromagnetic radiation:

Implementation Method 2

the portable device transmits a signal of data based on a reception intensity of a measurement signal transmitted from the vehicle-side device

Methodology Applied

Scientific EffectSignal reception and intensity detection:

Data Source

PatentEP3144454B1Keyless entry device

Publication Date: 2019.10.16 ALPS ALPINE CO LTD

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AI summary

[Object] A keyless entry apparatus capable of reducing erroneous control by reliably confirming start-up of a portable device even when a user carries an information device is provided. [Solution] A vehicle-side device that is provided on the vehicle side and transmits a signal at a first frequency, and a portable device that is able to be carried by a user and transmits a signal at a second frequency are included. The portable device transmits a signal of data based on a reception intensity of a measurement signal transmitted from the vehicle-side device, and the vehicle-side device performs predetermined control on the basis of the data based on the reception intensity of the measurement signal transmitted from the portable device. The vehicle-side device transmits a start-up signal to the portable device, the portable device transmits a request signal or a signaling signal to the vehicle-side device in each predetermined time when receiving the start-up signal, and the vehicle-side device transmits the measurement signal to the portable device each time the vehicle-side device receives the request signal or the signaling signal.