Half-hemisphere antennas for PEPS location detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional passive entry/passive start (PEPS) systems using low-frequency signals struggle to accurately detect the location of a remote device relative to a vehicle beyond a few meters, limiting the availability of vehicle functions due to the long wavelength of LF signals and their propagation characteristics.
Innovation Solution
The use of half-hemisphere antennas, which are directional and have a large gain pattern in one direction and a lower gain pattern in the remaining directions, allows for the determination of a remote device's location by analyzing signal strength differences between paired antennas, enabling accurate positioning and activation of vehicle functions at greater distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If low-frequency signals are used for communication, then communication range is extended, but location detection accuracy deteriorates
Solution Approach 1:
The system divides the single antenna into multiple antenna elements (first antenna and second antenna) that work together to provide both extended range communication and accurate location detection through signal strength comparison
Solution Approach 2:
The patent introduces signal strength as an intermediary parameter that bridges the gap between long-range communication and precise location detection, using the relative signal strengths from multiple antennas to determine device position
2Reliability
If conventional LF systems are used, then communication is reliable within a few meters, but vehicle function availability deteriorates at greater distances
Solution Approach 1:
The system changes the operational parameters by using multiple antennas with different orientations and comparing their signal strengths, enabling the system to maintain reliability while extending adaptability to greater distances for vehicle function activation
3Speed
If smart devices are used for long-range communication, then communication range is extended, but location detection capability deteriorates
Solution Approach 1:
The patent introduces signal strength comparison from multiple antennas as an intermediary mechanism that enables location detection capability to be restored even when using smart devices for long-range communication
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 the accurate detection of a remote device's location relative to the vehicle, allowing for the activation of vehicle functions even at longer ranges, such as 100 meters, by utilizing the signal strength differences between half-hemisphere antennas to determine the device's position and proximity.
Implementation Method 1
Conventional passive entry/passive start (PEPS) systems, which are vehicle systems that include a keyless entry system, may provide a user access to various vehicle functions if the user possesses a key fob that has been previously paired with a vehicle's central PEPS electronic control unit (ECU). As an example, the user in possession of the key fob may unlock and enter the vehicle by grabbing the door handle.
Implementation Method 2
uses the signal strength obtained by a plurality of sensors to estimate the distance between the key fob and the vehicle and the location of the key fob relative to the vehicle
Data Source
AI summary
A method and apparatus includes a processor that receives information corresponding to a first signal strength of a communication link between a remote device and a communication gateway of a vehicle. The information corresponding to the first signal strength is associated with a first antenna of a sensor and the first antenna includes a first peak main lobe magnitude oriented in a first direction. The processor also receives information corresponding to a second signal strength of the communication link. The information corresponding to the second signal strength is associated with a second antenna. The second antenna includes a second peak main lobe magnitude oriented in a second direction. The processor executes a first boundary line determination that includes determining whether the remote device is located on a first side of a boundary line based on the first signal strength and the second signal strength.