Vehicle Cabin Device Positioning Against UWB Reflection Errors
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Solution Overview
Problem
High-frequency signals used for improved location accuracy in vehicles can be distorted by reflections from objects and human bodies, leading to false detection of user devices outside the passenger compartment, preventing engine startup.
Innovation Solution
A method that calculates the positional variation of a user device by comparing distances from transceivers using received response signals, excluding erroneous signals above a predetermined threshold to prevent false detection, and including all signals for accurate positioning when movement is detected within the compartment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency signals (UWB) are used for location determination, then location accuracy is improved, but signal reflections from objects and human bodies cause false detection of user devices outside the passenger compartment
Solution Approach 1:
The system uses feedback by comparing the currently determined position with the previously determined position. If the positional variation exceeds a threshold, the system recalculates the position using all transceiver signals, including potentially reflected ones. This feedback mechanism allows the system to adapt to movement while filtering out false detections from reflections.
Solution Approach 2:
The system performs preliminary determination of the user device position using high-frequency signals from multiple transceivers. This preliminary position is then used as a reference to detect and filter erroneous measurements caused by signal reflections before final position acceptance.
2Measurement precision
If multiple transceivers are used to determine position, then location accuracy is improved, but calculation complexity increases due to needing to process and validate multiple distance measurements
Solution Approach 1:
The system calculates position using only the subset of transceiver signals that are consistent with the previously determined position. When reflections cause erroneous distance measurements, the system excludes those specific transceiver signals from the calculation, using only the valid ones. This partial action approach reduces calculation complexity while maintaining accuracy.
3Reliability
If signal reflections are filtered out to prevent false detection, then detection reliability is improved, but positioning accuracy may deteriorate when the user device moves within the compartment
Solution Approach 1:
The system dynamically adjusts its signal filtering strategy based on the detected movement. When the user device is stationary, the system filters out reflected signals to prevent false detections. When movement is detected (positional variation exceeds threshold), the system includes all transceiver signals in the position calculation, even potentially reflected ones, to maintain accurate tracking of the moving device.
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
Prevents false detection of user devices outside the passenger compartment, ensuring accurate positioning and allowing vehicle systems to start correctly by filtering out incorrect signal reflections.
Implementation Method 1
each transceiver calculates the total time of flight of the request signal and of the response signal or else determines the power of the received response signal in order to determine the distance
Implementation Method 2
these high-frequency signals may be more easily reflected by objects and by the human body. Thus, a reflected signal will follow a longer path that will distort calculation of the distance
Data Source
AI summary
A method for managing location of a user device in a passenger compartment of a vehicle is disclosed. The method includes calculating the distance of the user device in relation to each of the transceivers from the received response signals; calculating, for each transceiver, the difference between the calculated distance between the transceiver and the user device and the distance between the transceiver and the user device that was previously used to determine the position of the user device in the passenger compartment. When one of the differences calculated in relation to one of the transceivers is erroneous by being higher than a predetermined “inconsistency threshold”, the method then calculates the positional variation of the user device from the received response signals by excluding the response signal received for the transceiver.