Vehicle Access Arrangement Using UWB Time-of-Flight
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Solution Overview
Problem
Modern vehicle access systems are vulnerable to relay attacks, which can lead to theft, as they rely on a question-and-answer dialog between the vehicle and a driver's mobile identification transmitter, lacking sufficient security measures.
Innovation Solution
The access arrangement employs a vehicle transmission/reception device that transmits interrogation signals and measures the time interval between signal transmission and response, using time-of-flight measurements to prevent middleman attacks and determine the location of the mobile identification transmitter, allowing for appropriate control commands based on static or dynamic situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a question-and-answer dialog is used for passive access control, then convenience for the driver is improved, but security against relay attacks deteriorates
Solution Approach 1:
The patent introduces time-of-flight measurement as an intermediary verification mechanism. Instead of relying solely on the question-and-answer dialog, the system measures the physical time it takes for signals to travel between the vehicle and the identification transmitter. This intermediary measurement acts as a mediator that validates the authenticity of the communication, preventing relay attacks while maintaining the passive convenience of the original access method.
Solution Approach 2:
The patent replaces the purely cryptographic verification mechanism with a physical measurement-based verification. By substituting the mechanical/electronic signal exchange with a time-of-flight measurement that captures physical reality (the actual distance and time), the system undermines relay attacks that attempt to intercept and forward signals. The physical measurement substitution creates a fundamental barrier that cryptographic methods alone cannot provide.
2Reliability
If time-of-flight measurement is implemented to prevent relay attacks, then security is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing communication signals serve multiple functions. The same interrogation and response signals used for authentication also carry timing information for distance measurement. By making the communication protocol multi-functional (both authentication and ranging), the system avoids adding separate dedicated hardware for time-of-flight measurement, thereby limiting the increase in device complexity while achieving enhanced security.
Solution Approach 2:
The system uses the response time from the identification transmitter as feedback to determine distance and detect relay attacks. The identification transmitter's response time becomes a feedback signal that provides information about the physical state of the communication channel. This feedback mechanism allows the vehicle to verify the authenticity of the connection without requiring additional complex verification hardware.
3Productivity
If multiple interrogation signals are transmitted in short succession, then authentication speed is improved, but accuracy of distance measurement deteriorates
Solution Approach 1:
The patent applies preliminary calibration or compensation for the identification transmitter's processing time. Before performing the time-of-flight measurement, the system accounts for the fixed time the identification transmitter needs to process the interrogation signal and generate a response. By subtracting this known processing time from the total measured interval, the system achieves accurate distance measurements even when multiple signals are transmitted in quick succession, maintaining both authentication speed and measurement precision.
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 security by preventing relay attacks and ensuring that only authorized drivers can access the vehicle, while maintaining comfort by minimizing equipment requirements and using existing communication standards like UWB for precise location determination.
Implementation Method 1
the vehicle transmission/reception device is configured to receive corresponding response signals from the mobile identification transmitter in response to the transmitted interrogation signals in order to determine a respective time interval that has elapsed between the transmission of an interrogation signal and the reception of a corresponding response signal
Data Source
AI summary
An access arrangement for a vehicle comprises a vehicle transmission/reception device configured to transmit multiple interrogation signals to a mobile identification transmitter, receive corresponding response signals from the mobile identification transmitter in response to the transmitted interrogation signals, and determine a respective time interval that elapsed between the transmission of an interrogation signal and the reception of a corresponding response signal. Furthermore, the access arrangement comprises a vehicle control device configured to output a different control command based on a change in the specific time intervals for two transmitted interrogation signals. The interrogation signals and response signals are in accordance with the UWB standard. Based on the evaluation of the time-of-flight differences of two interrogation signals, it is possible to detect when the mobile identification transmitter changes location or remains at one location, and accordingly to output a different and appropriate control command by the vehicle control device.