Vehicle Presence Detection Oscillator Control for Low Power Radar
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Solution Overview
Problem
Existing presence detection systems for motor vehicles, particularly those using radar technology, face inefficiencies due to continuous signal transmission, which is energy-consuming, and require frequent oscillator stabilization and frequency checking, leading to high electricity consumption.
Innovation Solution
A presence detection system that uses a microcontroller and transceiver circuit with a piezoelectric element to periodically transmit signals, measuring and stabilizing frequency only during transmission intervals, eliminating the need for continuous power and phase-locked loop stabilization, thereby reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the oscillator is continuously stabilized using a phase-locked loop and frequency is continuously checked, then the frequency accuracy is improved, but the energy consumption increases significantly
Solution Approach 1:
The patent implements periodic frequency checking and stabilization instead of continuous operation. The microcontroller measures the oscillator frequency at specific intervals (e.g., every 10 seconds) and only activates the phase-locked loop when deviation exceeds a threshold, rather than maintaining continuous stabilization. This periodic approach maintains frequency accuracy while dramatically reducing energy consumption during idle periods.
Solution Approach 2:
The system uses the oscillator's own output signal to perform self-diagnosis and self-correction. The microcontroller measures the frequency of the oscillator's output and automatically adjusts the phase-locked loop activation based on measured deviations, enabling the system to service itself without external intervention while minimizing energy-consuming stabilization operations.
2Reliability
If the transceiver circuit transmits signals continuously, then the detection reliability is improved, but the energy consumption increases significantly
Solution Approach 1:
The transceiver circuit transmits radar signals periodically at predetermined intervals (e.g., every 10 seconds) rather than continuously. Between transmission periods, the system enters a low-power state. This periodic transmission maintains sufficient detection reliability for presence detection while dramatically reducing energy consumption compared to continuous operation.
Solution Approach 2:
The system dynamically adjusts its operation mode based on detected conditions. When a user presence is detected during a transmission cycle, the system can increase transmission frequency or activate additional functions. When no presence is detected, it reduces to minimal periodic transmissions, creating a dynamic balance between detection reliability and energy consumption.
3Stability of the object's composition
If the oscillator stabilization phase is repeated frequently, then the frequency stability is improved, but the energy consumption increases
Solution Approach 1:
The system implements feedback-based stabilization where the microcontroller measures the oscillator frequency and compares it against a reference value. The phase-locked loop is only activated when the measured frequency deviates from the reference by more than a predetermined threshold, creating an efficient feedback mechanism that maintains frequency stability while avoiding unnecessary energy-consuming stabilization cycles.
Solution Approach 2:
The system changes the operational parameters of frequency stabilization based on actual conditions. Instead of maintaining constant stabilization, the patent adjusts the stabilization intensity and frequency based on measured temperature variations, humidity changes, and detected frequency deviations, optimizing the balance between frequency stability and energy consumption.
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
Significantly reduces electricity consumption by up to 30 times compared to prior art, maintaining accurate frequency stabilization and detection of user presence with intermittent power usage.
Implementation Method 1
a) activate the piezoelectric element during what is called an "awake" time interval, in order to stabilize said piezoelectric element
Implementation Method 2
the oscillator is configured so as to receive a supply voltage and a reference electrical signal, and to supply a transmission signal when it is supplied by the supply voltage, with a frequency of the transmission signal that is a function of a reference formed by a feature of the reference electrical signal
Implementation Method 3
the antenna is configured so as to transmit said transmission signal from the oscillator so as to form a signal that is transmitted by the transceiver circuit
Implementation Method 4
using the stabilized piezoelectric element, measure the frequency of a Doppler signal resulting from said reflected signal
Data Source
AI summary
A device for a presence detection system for detecting the presence of a user close to a motor vehicle is configured to: activate a piezoelectric element during an “awake” time interval to stabilize the piezoelectric element; then, control the supply of voltage to an oscillator and supply the oscillator with a reference electrical signal forming a current voltage reference, so the transceiver circuit transmits a signal during what is called a “transmission” time interval; during the transmission time interval, measure the frequency of a reflected signal resulting from the transmitted signal, measure the frequency of the transmitted signal, and determine a corrected reference based on the measured frequency of the transmitted signal, allowing the oscillator to operate at a target frequency value. This allows limiting the energy consumption of a transceiver device used to detect the presence of a user close to a motor vehicle.