Smartphone Magnetic Sensor Vehicle Positioning
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Solution Overview
Problem
Existing vehicle keyless entry systems require the physical presence of a key to activate vehicle functions, limiting functionality when a smartphone or alternative portable apparatus is used.
Innovation Solution
A method utilizing a magnetic field sensor in a smartphone to detect and evaluate the magnetic field generated by a vehicle's LF antennas, determining the smartphone's position relative to the vehicle, and authenticating authorization through a challenge-response method to activate vehicle functions without the need for hardware modifications or additional antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a magnetic field sensor is used in a portable apparatus to detect the magnetic field generated by a vehicle, then the need for additional antennas or hardware modifications in the portable apparatus is eliminated, but the ability to determine position and authenticate authorization is achieved
Solution Approach 1:
The magnetic field sensor, originally designed for compass functionality in smartphones, is repurposed to detect the magnetic field generated by the vehicle's LF antennas. This allows the same sensor to serve dual purposes: navigation/orientation and vehicle authentication/position determination, eliminating the need for dedicated antennas or additional hardware in the portable apparatus.
Solution Approach 2:
Instead of requiring the portable apparatus to have its own transmitting antenna for active communication, the system uses the magnetic field sensor to passively detect and copy the magnetic field signature emitted by the vehicle's LF antennas. This copied field information is sufficient for position determination and authorization authentication.
2Adaptability or versatility
If conventional smartphones without additional antennas are used, then compatibility and ease of use are improved, but the capability to perform keyless entry and position determination is limited
Solution Approach 1:
The smartphone uses its existing magnetic field sensor (already present for compass functionality) to perform vehicle authentication and position determination. The system leverages resources already available in the smartphone, requiring no additional hardware, accessories, or user configuration, thereby maintaining both high compatibility and ease of use.
3Device complexity
If the magnetic field component of an electromagnetic field is detected, then position information can be obtained without additional hardware, but the detection capability must be sufficient to distinguish the vehicle-generated field from other magnetic fields
Solution Approach 1:
The system uses the magnetic field sensor to detect the magnetic field component and evaluates this information to determine position and authenticate authorization. The challenge-response authentication protocol provides feedback verification to ensure the detected magnetic field signature corresponds to an authorized vehicle, enabling precise differentiation between vehicle-generated fields and other magnetic fields in the environment.
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
Enables the use of a conventional smartphone to determine its position and authenticate authorization within the vehicle, allowing for the activation of vehicle functions without the need for physical keys, enhancing convenience and compatibility with existing vehicle systems.
Implementation Method 1
Generating a magnetic field by means of the vehicle. Particularly with its LF antennas (Low Frequency; LF antennas operate in the kHz range), the vehicle generates an alternating field, e.g., an electromagnetic field. This electromagnetic field has the magnetic field, so to speak, as a constituent or component.
Implementation Method 2
Detecting the magnetic field using a magnetic field sensor of the portable apparatus.
Data Source
AI summary
A method to determine a position of a portable apparatus relative to a vehicle including generating a magnetic field by the vehicle, detecting the magnetic field by a magnetic field sensor of the portable apparatus, and evaluating the magnetic field to determine the position of the portable apparatus relative to the vehicle.