Keyless Entry Position Determination Using Signal Intensity Segmentation
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Solution Overview
Problem
Existing keyless entry systems for vehicles face inaccuracies in determining the position of a portable device inside or outside the vehicle due to radio wave leakage and signal intensity variations, leading to incorrect determinations.
Innovation Solution
A keyless entry system apparatus that uses multiple transmitting antennas to send request signals, with a vehicle device and portable device exchanging answer signals, where the vehicle controller or portable controller compares signal intensity data to pre-stored inside and outside data groups to determine the position using Mahalanobis distances, allowing for accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmission power of radio wave from the transmitting antenna is increased to ensure the portable device can receive the signal inside the vehicle, then the signal coverage is improved, but radio wave leakage occurs causing incorrect position determination outside the vehicle
Solution Approach 1:
The patent divides the space into multiple regions by deploying multiple transmitting antennas at different locations (inside and outside the vehicle). Each antenna serves a specific spatial segment, allowing the system to determine position by comparing signal intensities from different segmented sources rather than relying on a single high-power antenna that causes leakage.
Solution Approach 2:
The patent applies local quality by having different transmitting antennas with potentially different transmission powers positioned at specific locations. The signal intensity characteristics are localized to specific regions, enabling the portable device to determine its position by comparing the local signal intensity patterns from different antenna locations.
2Measurement precision
If the transmission power of radio wave from the transmitting antenna is decreased to prevent radio wave leakage, then position determination accuracy outside the vehicle is improved, but the portable device cannot receive the signal inside the vehicle
Solution Approach 1:
The patent segments the transmission function across multiple antennas positioned both inside and outside the vehicle. This segmentation allows the system to maintain reliable signal coverage inside the vehicle while preventing leakage outside, as each antenna operates at appropriate power levels for its specific location and target region.
Solution Approach 2:
The patent merges the functions of multiple transmitting antennas to achieve both reliable indoor coverage and accurate outdoor position determination. By combining the signal intensity information from multiple antennas with different transmission powers and locations, the system achieves both reliability and precision simultaneously.
3Measurement precision
If multiple transmitting antennas are provided to improve position determination accuracy, then the ability to distinguish inside/outside position is improved, but the system complexity increases
Solution Approach 1:
The patent applies self-service by having the portable device itself perform the position determination calculations based on signal intensity comparisons. The vehicle's control unit stores reference data and the portable device's control unit processes the signal intensity information, distributing the computational workload and reducing the complexity burden on any single component.
Solution Approach 2:
The patent implements feedback by having the portable device measure signal intensities from multiple antennas, compare these measurements against reference data stored in the vehicle's control unit, and use this comparison feedback to determine its position. This feedback mechanism enables accurate position determination while keeping the system architecture relatively simple.
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 the accuracy of determining the portable device's position, reducing incorrect determinations and enabling secure locking and unlocking operations based on precise location assessment.
Implementation Method 1
a vehicle transmitter 11 which transmits a request signal to a portable device 3
Implementation Method 2
the portable device 3 detects the intensity of each signal transmitted from the plurality of transmitting antennas 15
Data Source
AI summary
A vehicle controller or a portable controller has a memory that stores an inside data group having information on the intensity of request signals transmitted from a plurality of transmitting antennas when a position of a portable device is the inside of a vehicle, and an outside data group having information on the intensity of request signals transmitted from the plurality of transmitting antennas when the position of the portable device is the outside of the vehicle. The vehicle controller determines whether the information on the intensity of request signals is closer to the inside data group or the outside data group stored in the memory.