Ultrasonic Measuring System Reducing Dead Time via Correlation
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Solution Overview
Problem
Ultrasonic measuring systems face a dead time during decay processes, limiting the minimum range they can detect obstacles, and existing frequency-modulated excitations are restrictive and limited to specific forms of transmission.
Innovation Solution
The system employs a resonant transducer element with a frequency-modulated transmitted signal, differing from the decay signal's resonance frequency, using a correlation filter to distinguish echo pulses from decay signals, allowing detection even during decay phases and reducing the minimum detectable range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a resonant transducer element is used to transmit ultrasonic pulses, then the transmission efficiency is improved, but a dead time occurs during decay processes which limits the minimum detection range
Solution Approach 1:
The patent applies parameter changes by modulating the frequency of the transmitted signal to differ from the resonance frequency of the transducer. This allows the system to transmit ultrasonic pulses efficiently at the resonance frequency while using a different frequency for the transmitted signal, enabling the correlation filter to distinguish between the decay signal and actual echo pulses, thereby reducing the dead time period
Solution Approach 2:
The patent introduces a correlation filter as an intermediary component that correlates the received signal with the transmitted signal. This intermediary mechanism enables the system to identify echo pulses even during the decay phase, effectively reducing the dead time while maintaining the benefits of resonant transmission
2Loss of time
If frequency-modulated excitation is used to reduce dead time, then the minimum range is reduced, but the system becomes limited to very special forms of transmission
Solution Approach 1:
The patent achieves universality by maintaining the resonant transducer element's ability to transmit ultrasonic pulses while adding frequency modulation capability. The system can operate with the transducer at its resonance frequency for efficient transmission while simultaneously applying frequency modulation to the transmitted signal, thus preserving transmission flexibility while reducing dead time
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 enables the detection of echoes superimposed on decay signals, reducing the dead time and minimum range, improving the system's ability to detect obstacles, especially small or poorly reflective ones, and increasing the maximum range.
Implementation Method 1
The sensors include a resonant transducer element whose emission frequency is coordinated with the resonance frequency of the transducer
Implementation Method 2
the at least one correlation filter being designed to correlate the signal generated by the resonant transducer with the transmitted signal and to generate a corresponding correlation signal
Data Source
AI summary
An ultrasonic measuring system is described for detecting an obstacle using a resonant transducer element for transmitting an ultrasonic pulse and for generating a received signal which includes the ultrasonic echo pulse reflected from the obstacle, the transducer element generating a decay signal having its resonance frequency after transmitting an ultrasonic pulse. The ultrasonic measuring system includes an evaluation unit having a control unit which is designed to activate the transducer element for transmitting the ultrasonic pulse with the aid of a frequency-modulated transmitted signal generated by the control unit, the frequency modulation taking place with the aid of a modulation signal in such a way that the signature of the ultrasonic pulse differs from that of the decay signal. The evaluation unit is designed to recognize the echo pulse based on an evaluation of a correlation signal which is generated with the aid of at least one correlation filter and which originates from the correlation of the signal generated by the resonant transducer element with the transmitted signal. Furthermore, a corresponding method is provided for detecting an obstacle with the aid of ultrasound, as well as a vehicle assistance system having the ultrasonic measuring system.