TPMS Emitter Movement Detection via Doppler Signal Analysis
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Solution Overview
Problem
Existing tire pressure monitoring systems (TPMS) are hindered by the high cost, size, and power consumption of accelerometers used to determine vehicle movement, necessitating a more compact, cost-effective, and low-power solution for detecting vehicle movement.
Innovation Solution
A method employing a Doppler effect-based approach to detect vehicle movement by inserting a periodic component into the signal emitted by the TPMS emitter, using an intermediate filter and fast Fourier transform to identify frequency deviations, allowing the TPMS emitter to switch between low consumption and driving modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an accelerometer is used to determine vehicle movement, then movement detection accuracy is improved, but device cost, size, and power consumption increase
Solution Approach 1:
The patent extracts the movement detection function from the accelerometer and implements it through signal processing of the radiofrequency signal already present in the TPMS system. By analyzing the Doppler effect on the radiofrequency signal, the system achieves movement detection without requiring the physical accelerometer component, thereby reducing device complexity, cost, and size while maintaining detection capability
Solution Approach 2:
The patent replaces the mechanical accelerometer with an electromagnetic field-based detection method. Instead of using a mechanical sensor to detect motion, the system uses the Doppler effect on radiofrequency signals to infer vehicle movement, substituting a mechanical system with an electromagnetic field-based solution that achieves the same functional outcome
2Measurement precision
If an accelerometer is used to determine vehicle movement, then movement detection accuracy is improved, but power consumption increases
Solution Approach 1:
The patent extracts the movement detection function from the power-consuming accelerometer and implements it through processing of the existing radiofrequency signal. By using the Doppler effect analysis on the radiofrequency signal already being transmitted and received in the TPMS system, movement detection is achieved without the additional power consumption of an accelerometer
Solution Approach 2:
The patent makes the radiofrequency signal serve multiple functions: it continues to provide tire pressure monitoring data while simultaneously enabling vehicle movement detection through Doppler effect analysis. This multi-functionality eliminates the need for a separate accelerometer and its associated power consumption, as the same signal infrastructure is used for both purposes
3Measurement precision
If a TPMS emitter includes an accelerometer, then movement detection capability is improved, but the emitter becomes less compact
Solution Approach 1:
The patent extracts the movement detection capability from the physical accelerometer component and implements it through software-based signal processing of the radiofrequency signal. By analyzing Doppler shifts in the radiofrequency signal, the system achieves movement detection without the space requirements of an accelerometer, thereby maintaining a compact emitter design
Solution Approach 2:
The patent creates a virtual copy of the accelerometer's movement detection function through signal processing algorithms that analyze the Doppler effect on the radiofrequency signal. Instead of using a physical sensor, the system uses computational methods to replicate the movement detection capability, eliminating the need for additional physical components and maintaining compact dimensions
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 detection of vehicle movement without the need for an accelerometer, resulting in a more compact, cost-effective, and energy-efficient TPMS emitter that can accurately determine vehicle movement and adjust operating modes accordingly.
Implementation Method 1
the communication between the monitoring receiver and each emitter for monitoring the pressure being subjected to a Doppler effect so that a periodic component is inserted into the signal emitted, by the emitter, to the receiver
Data Source
AI summary
A method for determining the start of movement of a motor vehicle equipped with a system for monitoring tire pressure of a motor vehicle. Communication between the receiver and each pressure monitoring system emitter being subjected to a Doppler effect so that a periodic component is inserted by the emitter into the signal emitted to the receiver. The method includes: acquiring the intermediate-frequency signal before demodulation by a processor to extract data carried by the radiofrequency signal, determining the FFT of the IF signal, determining the average value of the FFT of the IF signal over a preset duration, and determining whether there is a frequency deviation by comparing the instantaneous value of the fast Fourier transform to the average value of the fast Fourier transform, if so, determining whether the emitter for monitoring the pressure of a tire is moving and that the vehicle is moving.