Adaptive Threshold Control for Vehicle Access Signal Detection
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Solution Overview
Problem
Existing motor vehicle access and locating systems face challenges in securely identifying the first path signal amidst noise and multipath propagation, balancing security and performance in time-of-flight measurements, and maintaining resistance against relay attacks.
Innovation Solution
A control device that determines the time of flight of the peak path signal, adjusts the threshold value for the first path search based on the time interval, and dynamically adjusts the security margin to ensure reliable signal detection, integrating signal-to-noise ratio and location-specific parameters to enhance security and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed high threshold value is used for first path search to ensure security, then relay attack resistance is improved, but detection reliability deteriorates when time interval varies
Solution Approach 1:
The patent applies dynamics by making the threshold value adaptive rather than fixed. The threshold is dynamically adjusted based on the measured time interval δ, allowing the system to optimize detection sensitivity for each specific measurement scenario while maintaining security requirements.
Solution Approach 2:
The patent changes the threshold parameter based on the time interval measurement. By establishing a relationship between the time interval δ and the appropriate threshold value, the system adapts its detection criteria to match the actual signal conditions, improving both security and detection reliability.
2Measurement precision
If threshold value is adjusted based on time interval to improve detection accuracy, then first path search reliability is improved, but system complexity increases
Solution Approach 1:
The patent implements parameter changes by establishing a functional relationship between the time interval δ and the threshold value. This allows the system to adapt the threshold based on measured conditions without requiring complex real-time optimization algorithms, balancing improved detection reliability with acceptable system complexity.
3Measurement precision
If time interval δ is enlarged to search for first path signal, then detection coverage is improved, but false detection risk increases
Solution Approach 1:
The patent addresses this contradiction by dynamically adjusting the threshold parameter based on the time interval δ. When δ is enlarged to expand detection coverage, the threshold is simultaneously adjusted to maintain appropriate selectivity, thereby reducing false detection risk while preserving expanded search capability.
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 effectively reduces the risk of relay attacks by ensuring accurate and secure identification of the first path signal, improving accuracy and dynamic range, and adapting to varying security requirements based on location and usage scenarios.
Implementation Method 1
determining the time of flight (ToF) of the peak path signal
Data Source
AI summary
Disclosed are a control device for a motor vehicle access or locating system and a method for operating a motor vehicle access or locating system, having the steps of: identifying a received signal that has travelled from a transmitter to a receiver of a control device along the strongest signal path, the peak path, as the peak path signal; determining the time of flight, ToF, of the peak path signal; determining a time interval, δ, of the time of flight of the peak path signal; determining a threshold value, T, for the reliability of a first path search depending on δ; carrying out the first path search at δ taking the threshold value into consideration.