Ultrasonic Distance Sensing with Time-Gated FMCW Echo Analysis
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Solution Overview
Problem
Existing ultrasonic distance sensors have limited measurement distance and resolution due to variations in ultrasonic wave speed and energy caused by sound propagation properties in air or other mediums, leading to errors in distance measurement.
Innovation Solution
An ultrasonic distance sensor that generates a continuous frequency-modulated ultrasonic signal array, performs time gating to select specific signals, and uses signal processing to measure object location through echo signal analysis, enhancing measurement accuracy and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ultrasonic distance measurement is used, then the measurement method is simple and inexpensive, but the measurement distance and resolution are limited
Solution Approach 1:
The patent segments the continuous ultrasonic signal into multiple discrete signals with different frequencies. Each frequency component is processed separately through mixing and frequency analysis, allowing the system to achieve high resolution by combining multiple segmented measurements rather than relying on a single broadband signal.
Solution Approach 2:
The patent transforms the measurement from a single time-domain measurement to a multi-dimensional frequency-domain analysis. By using frequency-modulated signals and performing Fast Fourier Transform analysis, the system adds a frequency dimension to the measurement process, enabling higher precision distance and location measurement.
2Measurement precision
If ultrasonic waves are used for distance measurement, then simple equipment is required, but errors occur due to variations in sound propagation properties
Solution Approach 1:
The patent changes the frequency parameter of the ultrasonic signal continuously across multiple signals. By measuring at multiple different frequencies and combining the results through frequency analysis, the system compensates for variations in sound propagation properties, as different frequencies are affected differently by environmental factors, allowing error cancellation and improved accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the measured echo signals are mixed with reference signals of known frequencies, and the frequency analysis results are used to iteratively refine the distance measurement. The system uses the frequency spectrum information to feedback-correct the position estimates, improving reliability.
3Measurement precision
If frequency-modulated continuous ultrasonic signals are used, then measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent designs the signal generator to produce multiple frequency components in a unified continuous signal structure. The same hardware platform performs both signal generation and frequency analysis functions, making the system multi-functional. The Fast Fourier Transform processor serves both to analyze incoming echo signals and to process the frequency-modulated reference signals, reducing overall system complexity despite the advanced measurement technique.
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
The proposed solution improves measurement accuracy and resolution by using frequency-modulated signals and time gating, reducing errors caused by sound propagation variations and extending the effective measurement distance.
Implementation Method 1
ultrasonic waves are generated and incident on an object, and a distance to the object is measured by calculating time taken for the ultrasonic waves to reflect back from the object
Implementation Method 2
a signal generator configured to generate a continuous ultrasonic signal array that is frequency modulated
Implementation Method 3
a gating switch configured to perform time gating to allow part of ultrasonic signals in the continuous ultrasonic signal array to pass through the gating switch
Implementation Method 4
The signal processor may be configured to measure the location of the object by performing frequency analysis on the first mixed signal through Fast Fourier transform (FFT)
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
An ultrasonic distance sensor is provided. The ultrasonic distance sensor according to an embodiment includes: a signal generator configured to generate a frequency-modulated continuous ultrasonic signal array; a gating switch configured to perform time gating to allow part of ultrasonic signals in the continuous ultrasonic signal array to pass therethrough; a transmitter configured to emit ultrasonic signals, having passed through the gating switch, toward an object; a receiver configured to receive an echo signal reflected from the object; and a signal processor configured to measure a location of the object by using the echo signal.