Vehicle Alarm System Using Wireless Authentication and State Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Smart entry systems for vehicles face challenges in implementing an alarm function when the movement of a user cannot be detected based on position detection of a device with electronic key functionality, particularly when a fixed key unit is used instead of an electronic key.
Innovation Solution
A vehicle alarm system comprising a first device mounted on the vehicle that authenticates a second device through wireless communication and detects state changes to simulate the movement of an electronic key, allowing for alarm output when the user gets out or returns to the vehicle without turning off the ignition switch, using antennas and seating sensors to monitor vehicle states and radio wave intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed key unit is used instead of an electronic key, then the alarm function cannot be implemented because user movement cannot be detected, but the electronic key function can be controlled through wireless communication from a portable terminal device
Solution Approach 1:
The patent creates a virtual electronic key by copying the authentication functionality to the portable terminal device. The key unit stores authentication information and performs wireless communication authentication with the terminal device, effectively creating a digital replica of the physical key that can be remotely controlled and monitored.
Solution Approach 2:
The portable terminal device acts as an intermediary between the user and the key unit. It mediates the authentication process by communicating with the key unit wirelessly, and also serves as the monitoring point for detecting when the user (and terminal device) moves away from the vehicle, enabling the alarm function.
2Measurement precision
If the electronic key moves with the user from the driver's seat to the outside of the vehicle cabin, then the in-vehicle device can detect the movement and output an alarm, but when the key unit is fixed to the vehicle, the movement of the user cannot be detected
Solution Approach 1:
The patent replaces the mechanical approach of physically attaching the key to the user (electronic key carried in pocket) with a wireless communication-based system. The portable terminal device carried by the user communicates wirelessly with the fixed key unit, allowing position detection through communication status rather than mechanical attachment.
Solution Approach 2:
The fixed key unit serves multiple functions: it authenticates the portable terminal device, enables vehicle operations, and monitors user position by detecting communication status. This multi-functionality allows the system to maintain alarm capabilities without requiring the key unit to be physically attached to the user.
3Reliability
If the first device detects that the first wireless communication processing is stopped, then it outputs an alarm instruction, but it needs to distinguish between legitimate key removal and unauthorized access attempts
Solution Approach 1:
The system implements continuous feedback through periodic wireless communication between the key unit and portable terminal device. The key unit monitors communication status in real-time, and when communication stops (indicating the terminal device has moved away), it triggers an alarm instruction. This feedback mechanism allows the system to accurately detect when the user has left the vehicle while maintaining normal operation during authorized use.
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
Enables the implementation of an alarm function even when user movement cannot be detected by position, effectively alerting the user to leave the ignition on and preventing unauthorized exit or re-entry, by simulating electronic key movement based on vehicle state changes.
Implementation Method 1
The first device is configured to authenticate the second device by first wireless communication processing with the second device
Implementation Method 2
The second device is configured to measure a radio field intensity of a radio wave received from the portable terminal device
Data Source
AI summary
A vehicle alarm system includes a first device mounted on a vehicle, and a second device mounted on the vehicle. The first device authenticates the second device by first wireless communication processing with the second device, detects that a state of the vehicle is changed in a predetermined pattern in a case where the second device is successfully authenticated, and outputs a predetermined alarm instruction when the first device detects that the first wireless communication processing is stopped. The second device authenticates a portable terminal device by second wireless communication processing with the portable terminal device, and performs the first wireless communication processing with the first device in a case where the portable terminal device is successfully authenticated. The first device causes the second device to stop the first wireless communication processing when the first device detects a predetermined first state change of the vehicle.