Vehicle Exterior Antenna Layout for Key Fob Positioning Accuracy
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Solution Overview
Problem
Existing positioning systems for vehicles struggle to accurately determine the position of a portable terminal relative to a vehicle, particularly in distinguishing between the operating area and the prohibiting area using high-frequency radio waves due to signal attenuation and interference from the vehicle body.
Innovation Solution
A positioning system employing a vehicular exterior communication device with an antenna positioned at the side surface of the vehicle, facing upward or downward, to detect the reception strength of high-frequency radio waves from a portable terminal, allowing for precise differentiation between the operating and prohibiting areas by minimizing signal entry into the vehicle compartment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-frequency radio waves (1 GHz or higher) are used for wireless communication between vehicle and portable terminal, then communication speed and data transmission capability are improved, but signal attenuation and interference from vehicle body increase, reducing positioning accuracy
Solution Approach 1:
The patent changes the spatial dimension of antenna placement from interior to exterior of the vehicle. By positioning the antenna on the exterior surface, the system creates a new spatial relationship that avoids signal blockage by the vehicle body, thereby maintaining high-frequency communication benefits while improving positioning accuracy through reduced signal attenuation.
Solution Approach 2:
The vehicular exterior communication device acts as an intermediary between the portable terminal and the vehicle interior systems. This external device receives signals from the portable terminal and transmits them to the vehicle's interior communication system, eliminating direct signal path obstruction by the vehicle body and improving signal reception quality for positioning purposes.
2Device complexity
If antenna is positioned inside the vehicle compartment, then installation is simple and device complexity is reduced, but signal reception accuracy deteriorates due to interference from vehicle body and inability to distinguish operating area from prohibiting area
Solution Approach 1:
The patent relocates the antenna from the interior three-dimensional space to the exterior surface of the vehicle, fundamentally changing the spatial configuration. This dimensional shift allows the antenna to operate in a space free from vehicle body interference, enabling accurate signal reception and proper distinction between operating and prohibiting areas.
Solution Approach 2:
The patent applies local quality by positioning the antenna at a specific location on the exterior surface where signal reception characteristics are optimal. This localized placement ensures that the antenna operates in an environment with minimal interference, creating a zone of high signal quality external to the vehicle body.
3Device complexity
If conventional interior positioning system is used, then system simplicity is maintained, but ability to accurately distinguish operating area from prohibiting area is lost, leading to security issues
Solution Approach 1:
The vehicular exterior communication device serves as an intermediary that enables accurate area distinction. By positioning the antenna externally, this intermediary device can properly detect signal strength differences between operating and prohibiting areas, providing reliable security functionality without requiring complete system redesign.
Solution Approach 2:
The patent segments the communication system into exterior and interior components. The exterior communication device handles signal reception and positioning determination, while the interior vehicle systems handle execution of access control. This segmentation allows the critical positioning function to operate from an optimal external location while maintaining overall system simplicity.
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 configuration enhances the accuracy of determining the portable terminal's position, reducing erroneous determinations and effectively limiting automatic door unlocking to the intended operating area, thereby improving security and functionality.
Implementation Method 1
an antenna 31, which receives a wireless signal transmitted from the portable terminal 2
Data Source
AI summary
A positioning system includes a vehicular exterior communication device and a positioning device. The vehicular exterior communication device has an antenna and a strength detector. The antenna is disposed at a side surface portion of the vehicle that receives a wireless signal transmitted from the portable terminal. The strength detector detects reception strength of the wireless signal received by the antenna. The positioning device determines whether the portable terminal is present at an operating area based on vehicular exterior device strength as the reception strength of the wireless signal from the portable terminal detected by the vehicular exterior communication device. The vehicular exterior communication device is disposed under a door of the vehicle in a posture in which a center of directivity of the antenna faces upward or downward.