Distance Measurement Apparatus for Relay Attack Detection
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Solution Overview
Problem
Existing keyless entry systems for vehicles are vulnerable to relay attacks, where unauthorized individuals can intercept and relay communication signals between the key and the vehicle, leading to potential theft, as current preventive measures do not effectively detect relayed carrier signals.
Innovation Solution
A distance measurement apparatus that calculates distances between a key and a vehicle using carrier phase detection and measures received signal strength indicators (RSSIs) to determine if carrier signals have been relayed, by performing multiple distance measurements and analyzing the variance of RSSIs and measured distance values to identify potential relay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carrier signals are transmitted and received to measure distance between key and automobile, then distance measurement capability is improved, but vulnerability to relay attacks increases
Solution Approach 1:
The system transmits multiple carrier signals and receives feedback in the form of reflected signals. By analyzing the phase differences and signal strength indicators (SSIs) of these reflected signals, the system can detect anomalies that indicate relay attacks. The feedback mechanism allows continuous monitoring and comparison of signal characteristics to identify unauthorized relayed communications.
Solution Approach 2:
The system performs preliminary distance measurements and SSI comparisons before final authentication. By pre-establishing baseline signal characteristics and comparing incoming signals against these baselines, the system can proactively identify relay attacks before they compromise security. This preliminary analysis includes checking phase consistency and SSI relationships across multiple carrier signals.
2Measurement precision
If multiple carrier signals are transmitted for distance measurement, then measurement accuracy is improved, but system complexity increases
Solution Approach 1:
The system segments the distance measurement process into distinct phases: transmitting multiple carrier signals with different frequencies, receiving reflected signals for each frequency, measuring phase differences individually, and comparing SSI values. This segmentation allows complex multi-frequency measurements to be broken down into manageable, independent processing steps that can be executed systematically.
Solution Approach 2:
The system changes physical parameters by using multiple carrier frequencies (e.g., 433.92 MHz, 868.42 MHz, 2.4 GHz) instead of a single frequency. This parameter variation enables the system to achieve more accurate distance measurements through frequency diversity while managing complexity through standardized processing routines for each frequency band.
3Reliability
If distance measurement is performed multiple times to detect relay attacks, then security detection capability is improved, but time consumption increases
Solution Approach 1:
The system performs distance measurements periodically by transmitting multiple carrier signals in sequence and analyzing their reflected signals. This periodic measurement approach allows the system to gather sufficient data for reliable relay attack detection while maintaining reasonable timing. The periodic nature enables systematic comparison of phase differences and SSI values across multiple measurement cycles.
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
Effectively prevents unauthorized access by accurately distinguishing between legitimate and relayed signals, ensuring secure locking and unlocking of vehicle doors based on accurate distance measurements and signal correlation analysis.
Implementation Method 1
calculates a plurality of distances between a key and a vehicle based on carrier phase detection
Implementation Method 2
measures respective received signal strength indicators of the plurality of carrier signals
Data Source
AI summary
A distance measurement apparatus, which calculates distances between a first device and a second device based on carrier phase detection, includes a distance measurement operation unit that calculates the distances based on respective phases of a plurality of carrier signals included in each of a first distance measurement signal and a second distance measurement signal respectively transmitted from the first device and the second device, a received signal strength indicator measurement unit that measures respective received signal strength indicators of at least some of the plurality of carrier signals, and a carrier signal relay presence or absence judgment unit that judges presence or absence of relay of the carrier signals based on distance information about the plurality of distances calculated in the distance measurement operation unit and received signal strength indicator information about the plurality of received signal strength indicators measured in the received signal strength indicator measurement unit.