Keyless Entry Position Judgment Using Signal Intensity Data
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Solution Overview
Problem
Existing keyless entry systems for vehicles face accuracy issues in determining the position of a portable device relative to the vehicle's interior or exterior, particularly when the device is far from the boundary, leading to misjudgments and increased processing time.
Innovation Solution
A keyless entry system that uses Mahalanobis distance calculations and neural networks to accurately determine the position of a portable device by comparing signal intensity data from multiple antennas, reducing the need for extensive data acquisition beyond the boundary and minimizing processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If data is acquired only from the vicinity of the boundary to reduce processing time, then processing time is reduced, but accuracy for positions far from the boundary deteriorates
Solution Approach 1:
The patent divides the judgment process into two segments: first, a rough position judgment is performed using a small amount of boundary data to determine which side of the boundary the device is on; second, if higher precision is needed, additional data acquisition is performed only for that specific side. This segmentation allows the system to achieve adequate accuracy for most cases while maintaining fast processing, and only expands data collection when truly necessary.
Solution Approach 2:
The patent implements partial action by acquiring data only from the boundary vicinity initially, which is sufficient for most position judgments. Excessive action (acquiring data from positions far from the boundary) is performed only partially and conditionally - specifically, only when the initial judgment requires higher precision or when the device is actually located far from the boundary. This selective approach balances processing time and accuracy.
2Use of energy by moving object
If transmitting power is reduced to prevent radio wave leakage, then energy consumption is reduced, but signal reception reliability deteriorates
Solution Approach 1:
The patent implements dynamic transmitting power control where the transmission power is adjusted based on the judged position of the portable device. When the device is judged to be inside the vehicle, the transmitting power is reduced to prevent radio wave leakage and save energy. When the device is outside or the position is uncertain, the transmitting power is increased to ensure reliable signal reception. This dynamic adjustment resolves the contradiction between energy consumption and reception reliability.
Solution Approach 2:
The system uses feedback from position judgment results to control transmitting power. The position judgment (inside/outside the vehicle) feeds back to the transmitting power control mechanism, which adjusts power levels accordingly. This feedback loop ensures that power is optimized based on actual operational conditions, preventing both excessive energy consumption and signal reception failures.
3Measurement precision
If multiple transmitting antennas are used to improve position judgment accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies partial action by using a limited number of transmitting antennas (typically 2-4) positioned at key locations around the vehicle rather than deploying antennas throughout the entire vehicle structure. This partial deployment provides sufficient position judgment accuracy for determining whether the device is inside or outside the vehicle, while avoiding the complexity of extensive antenna networks. The system uses signal intensity comparisons from these limited antennas to achieve reliable position judgment.
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 system achieves high accuracy in judging the position of the portable device both near and far from the boundary, reducing errors and processing time, while maintaining efficient operation.
Implementation Method 1
the vehicle-side device judges that the portable device exists inside vehicle when the portable device receive a radio wave from the transmitting antennas inside the vehicle
Data Source
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AI summary
A keyless entry device can accurately judge where the portable device exists inside or outside a vehicle. The vehicle-side controller includes a memory which stores an inside data group having a plurality of intensity information of a request signal transmitted from the plurality of transmitting antennas when the portable device is located along an inside of a vehicle. Also included is, an outside data group having a plurality of intensity information of a request signal transmitted from the plurality of transmitting antennas when the portable device is located along an outside of the vehicle. The vehicle-side controller judges an area where the portable device exists from the intensity information of the request signal received from the portable device. The controller instantly judges the inside or the outside of the vehicle, when the portable device exists in an area apart from a boundary. The controller also judges which data group of the inside and outside data groups stored in the memory approximates the intensity information, when the portable device exists in the vicinity of the boundary.