Passive Keyless Entry Localization Using LF Fingerprinting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Passive keyless entry systems face challenges in reliably determining the proximity of a key to a reader, making them vulnerable to security breaches like relay attacks, and existing localization methods require complex and expensive hardware or show weak performance in accuracy and reliability.
Innovation Solution
A method using a monitoring unit and key that evaluates signal strength in various directions and angles, employing LF and RF signals, with a fingerprinting algorithm to determine the key's plausible location by comparing received signal strengths to expected values, and utilizing a gravitation vector for orientation and calibration to enhance security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If passive keyless entry systems are used for convenient access, then ease of operation is improved, but security reliability deteriorates due to vulnerability to relay attacks
Solution Approach 1:
The system performs preliminary localization and verification of the key's position and orientation before issuing access authorization. The monitoring unit captures the key's position and orientation data in advance, verifies plausibility of the localization result, and only then permits access. This preliminary verification prevents relay attacks by ensuring the key is physically present at the correct location and orientation.
Solution Approach 2:
The patent replaces traditional mechanical proximity detection with electromagnetic field-based localization using LF signals. Instead of relying solely on signal presence, the system uses magnetic field strength measurements and orientation detection to determine the key's precise position and orientation, making relay attacks detectable and preventable.
2Measurement precision
If traditional localization algorithms based on time measurements or wide bandwidth signals are used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The system changes the measurement parameters from time-based or wideband signal characteristics to magnetic field strength and orientation parameters. By measuring LF signal strength in multiple directions and analyzing the gravitation vector, the system achieves accurate localization and orientation detection using simple, low-cost hardware without requiring complex timing synchronization or wide bandwidth signals.
Solution Approach 2:
The monitoring unit performs multiple functions using the same LF transmitter and receiver: it transmits localization signals, measures magnetic field strength in various directions, detects key orientation via gravitation vector analysis, and verifies key authenticity. This multi-functional approach eliminates the need for separate complex hardware systems for each function.
3Reliability
If signal strength evaluation in multiple directions and angles is performed, then reliability of key position determination is improved, but loss of time for authorization increases
Solution Approach 1:
The system performs preliminary calibration during manufacturing to store expected signal strength values for different positions and orientations. During authorization, the system only needs to compare measured values against pre-stored references, significantly reducing processing time while maintaining high reliability in position determination.
Solution Approach 2:
The system uses feedback from the key's orientation detection (via gravitation vector) to optimize the measurement process. By determining the key's orientation first, the system can focus signal strength measurements on relevant directions only, reducing the number of measurements needed and thus the authorization time while maintaining accuracy.
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 significantly improves security by accurately determining the key's position and preventing unauthorized access, without the need for additional RF links or complex hardware, by using LF fingerprinting with magnetic field components and gravity vector analysis.
Implementation Method 1
the transmitter of the monitoring unit transmits signals and the key transmits response signals back to the monitoring unit
Implementation Method 2
The permissible position and/or permissible distance of the key are determined from the signals of the transmitter received by the key, wherein a signal strength of said signals is evaluated in various directions and/or angles
Data Source
AI summary
Presented are methods and devices for issuing an authorization for access to a secured area, particularly a building, a room, a vehicle, a computer system or the like, or for starting a machine, a vehicle, a computer or the like, having a monitoring unit comprising a transmitter, a receiver, and an evaluation device, and having a key, a key card or similar, referred to as a key in short below, having a transmitter, a receiver and an electronic device. A permissible position and/or a permissible distance between the transmitter of the monitoring unit and a permissible key is determined prior to issuing an authorization, wherein the transmitter of the monitoring unit transmits signals and the key transmits response signals back to the monitoring unit. The permissible position and/or the permissible distance of the key are determined from the signals received by the key, wherein a signal strength of said signals is evaluated in various directions and/or angles.