Vehicle Key Position Calibration for Accurate Radio Access Detection
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Solution Overview
Problem
Modern motor vehicles with automatically opening door systems face inaccuracies in position detection of portable key elements due to manufacturing deviations, varying electrical resistances, and differences in transmission and reception quality, which can lead to unreliable access control.
Innovation Solution
A method for calibrating position detection using a detection device with multiple antennas to determine signal strength and distance correlations, allowing for precise positioning through quadratic regression, and utilizing Bluetooth low energy for accurate positioning with low power consumption, enabling automatic and convenient calibration without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If position detection is based on signal strength correlation with distance, then automatic access control is enabled, but manufacturing deviations and varying electrical resistances cause inaccurate position detection
Solution Approach 1:
The patent performs preliminary calibration by detecting signal strengths at multiple known positions and storing reference values before actual operation. This preliminary action creates a baseline that compensates for manufacturing deviations and electrical resistance variations, enabling accurate automatic position detection despite component variations.
Solution Approach 2:
The system changes detection parameters by measuring signal strength at multiple different positions rather than relying on a single distance correlation. By collecting signal strength data across multiple positions and comparing with stored reference values, the system adapts to varying transmission powers and reception qualities while maintaining measurement precision.
2Adaptability or versatility
If multiple key elements with different transmission powers are supported, then versatility is improved, but position detection accuracy deteriorates due to varying transmission characteristics
Solution Approach 1:
The calibration method is designed to be universal and can be applied to any portable key element regardless of its specific transmission power or design. The system detects signal strengths at multiple known positions for each key element and creates element-specific reference profiles, enabling accurate position detection across different key element types without requiring manual configuration.
Solution Approach 2:
The system uses feedback by comparing currently detected signal strengths with previously stored reference values from calibration. This feedback mechanism allows the system to identify the key element's position based on signal strength patterns rather than absolute values, accommodating different transmission powers while maintaining detection accuracy.
3Measurement precision
If manual calibration procedures are implemented, then position detection accuracy is improved, but ease of operation deteriorates due to required manual intervention
Solution Approach 1:
The system performs self-calibration by automatically detecting signal strengths at multiple predetermined positions and storing reference values without requiring manual intervention. The portable key element and detection device work together autonomously to complete the calibration process, improving ease of operation while maintaining accuracy through multi-position signal strength measurement.
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
The method enhances the accuracy and convenience of position detection for portable key elements, allowing for precise access control and easy integration with various key elements, reducing the need for manual calibration and accommodating differences in transmission power and design.
Implementation Method 1
a detection device (52) configured to detect a position of the key element (46) relative to the motor vehicle (32) by radio
Implementation Method 2
A quadratic regression is useful because a received signal strength decreases with the squared distance
Data Source
AI summary
A method is proposed for calibrating a position detection of a portable key element by an access control system for a motor vehicle. The access control system comprises a detection device which is configured to detect a position of the key element relative to the motor vehicle by means of radio. The method comprises generating a first trigger signal when the key element is located in a first position relative to the motor vehicle and detecting a first signal strength in response to the first trigger signal. The method determines a correlation of signal strength and distance of the key element relative to the motor vehicle depending on the first signal strength at the first position. Furthermore, an access control system for a motor vehicle is proposed.