Hybrid Passive Entry Using RF and Magnetic Device Localization
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Solution Overview
Problem
Current automotive passive entry and start systems rely on bulky key fobs and short-range magnetic fields, making them susceptible to hacking and inconvenient for users.
Innovation Solution
The system uses a mobile device with RF and magnetic antennas to interact with a vehicle, determining its location using signal properties like RSSI and time-of-flight, and employing machine learning to classify regions around the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic fields are used for passive entry, then the key fob can determine its location relative to the vehicle, but the range is limited and the system is susceptible to hacking
Solution Approach 1:
The patent combines multiple signal types (magnetic field signals and RF signals) into a hybrid passive entry system. The magnetic antenna determines proximity while the RF antenna provides extended range communication, creating a multi-layered security approach that is more resistant to hacking than single-signal systems.
Solution Approach 2:
The mobile device serves multiple functions: it acts as both a key fob for vehicle access and a general-purpose communication device. The system can operate in different modes (proximity-based passive entry, extended-range RF communication, and hybrid mode) depending on the situation, providing versatile functionality while maintaining security.
2Ease of operation
If a dedicated key fob is used, then passive entry functionality is achieved, but the device becomes bulky and requires an additional item to be carried
Solution Approach 1:
The patent eliminates the need for a dedicated key fob by using a universal mobile device that consumers already carry. The mobile device performs both general communication functions and vehicle access functions, removing the need to carry a separate bulky key fob while maintaining passive entry convenience.
Solution Approach 2:
The system leverages the mobile device's existing capabilities (antennas, processors, power sources) to provide key fob functionality. Instead of requiring a specialized device, the system makes the consumer's existing mobile device serve the dual purpose of communication and vehicle access.
3Measurement precision
If magnetic antennas are used for location determination, then accurate proximity detection is achieved, but the signal range is short and cannot detect devices far from the vehicle
Solution Approach 1:
The patent merges magnetic antenna detection (for accurate close-range location) with RF antenna detection (for extended range) into a hybrid system. The magnetic antenna provides precise proximity determination when the device is near the vehicle, while the RF antenna extends the detection range to farther distances, creating a continuous detection spectrum.
Solution Approach 2:
The system uses the magnetic antenna's full capability for high-precision close-range detection, while the RF antenna provides supplementary longer-range detection. This partial use of each antenna's capabilities across different distance ranges creates a comprehensive detection system that overcomes the limitations of either antenna type alone.
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 solution enables secure and convenient passive entry and start without the need for a dedicated key fob, providing accurate location determination and enhanced security against hacking.
Implementation Method 1
The location of the key fob is determined using magnetic signals emitted from magnetic antennas in the car
Implementation Method 2
The mobile device can measure signal properties of the RF signals and the magnetic signals from the vehicle that relate to a distance of the device's antenna from a vehicle antenna
Implementation Method 3
Examples of signal properties include a received signal strength indicator (RSSI) and a time-of-flight value (e.g., a round trip time, RTT)
Data Source
AI summary
Methods and devices are provided for allowing a mobile device (e.g., a key fob or a consumer electronic device, such as a mobile phone, watch, or other wearable device) to interact with a vehicle such that a location of the mobile device can be determined by the vehicle, thereby enabling certain functionality of the vehicle. A device may include both RF antenna(s) and magnetic antenna(s) for determining a location of a mobile device relative to the vehicle. Such a hybrid approach can provide various advantages. Existing magnetic coils on a mobile device (e.g., for charging or communication) may be re-used for distance measurements that are supplemented by the RF measurements. Any device antenna may provide measurements to a machine learning model that determines a region in which the mobile device resides, based on training measurements in the regions.