RSSI Threshold Mapping for Vehicle Transmitter Location
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Solution Overview
Problem
Existing methods for determining the location of a remote transmitter in relation to a vehicle, such as in PEPS systems, are inaccurate due to distortion caused by metal parts of the vehicle, which affects the correlation between received signal strength indication (RSSI) values and distance or position.
Innovation Solution
A method involving the transmission of multiple measuring signals from various antennae, receiving RSSI values, and using threshold functions in an RSSI domain to determine if the remote transmitter is inside or outside a predefined region, by calculating differences between received RSSI values and threshold values derived from the RSSI domain map.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RSSI values are used to determine distance or position of the remote transmitter, then location determination is enabled, but the accuracy deteriorates due to distortion caused by metal parts of the vehicle
Solution Approach 1:
The patent changes the parameter space from physical distance/position to RSSI domain. Instead of directly using RSSI to calculate distance (which is distorted by metal parts), the invention creates a mapping in the RSSI domain that accounts for the distortion. Multiple RSSI measurements from different antennas are transformed into a location determination through threshold functions, effectively changing how the measurement is processed to compensate for the distortion caused by vehicle metal parts.
2Measurement precision
If multiple measuring signals are transmitted from multiple antennae to improve location accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent segments the location determination problem into multiple independent RSSI measurements from different antennas. Each antenna provides a separate measurement, and these segmented measurements are then processed individually through threshold functions before being combined to determine the final location. This segmentation allows the system to handle the complexity of multiple measurements through a modular approach rather than requiring a complex integrated solution.
Solution Approach 2:
The patent introduces threshold functions as intermediaries between the raw RSSI measurements and the final location determination. These threshold functions act as a mediator that transforms the complex multi-antenna RSSI data into a simplified decision framework. Instead of directly processing multiple RSSI values to calculate position, the threshold functions serve as an intermediate layer that makes the location determination more manageable and less complex.
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 approach provides a robust and accurate method for determining the location of the remote transmitter, allowing for precise identification of its position relative to the vehicle, thereby enhancing the reliability of vehicular operations.
Implementation Method 1
transmitting at least two measuring signals to the remote transceiver, each of the measuring signals being transmitted from a different one of a plurality of n antennae
Implementation Method 2
receiving an acknowledgement signal from the remote transmitter in response to each measuring signal, each acknowledgement signal including a received signal strength indication (RSSI) for a respective received measuring signal
Data Source
AI summary
A method for determining the location of a remote transceiver in relation to a vehicle, the method including the steps of: transmitting at least two measuring signals to the remote transceiver, each of the measuring signals being transmitted from a different one of a plurality of n antennae positioned relative to the vehicle, where n denotes an integer≧2; receiving an acknowledgement signal from the remote transmitter in response to each measuring signal, each acknowledgement signal including a received signal strength indication (RSSI) for a respective received measuring signal, the values of the received RSSIs together defining a data point in an RSSI domain; and determining a difference between the received value of a first RSSI and a defined threshold value for that first RSSI, wherein the sign of the difference indicates whether the remote transmitter is inside or outside a defined region i of or near the vehicle.