Echo Profile Leading Edge Parabola Fitting for Ranging Accuracy
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Solution Overview
Problem
Pulse-echo ranging systems face accuracy issues in determining echo arrival time due to environmental and target object effects, particularly in low dielectric constant liquids and open channel monitoring, where echo profiles are distorted by ring-down oscillations and strong echoes, leading to inaccurate measurements.
Innovation Solution
The method focuses on using only the leading edge of the echo profile by fitting a parabola to a selected portion and determining its temporal position, employing the least-squares method to minimize offsets, allowing the parabola's width to vary, and combining this with center of mass evaluation for near ranges to enhance robustness and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the peak or trailing edge of the echo profile is used for measurement, then the measurement can be performed in various conditions, but the measurement precision deteriorates due to distortion from ring-down oscillations and environmental factors
Solution Approach 1:
The invention extracts only the leading edge portion of the echo profile for measurement, separating it from the distorted peak and trailing edge regions. This extraction is achieved by identifying the leading edge start point and end point, then isolating the signal portion between these points for parabola fitting, thereby eliminating the harmful effects of ring-down oscillations and environmental distortions on measurement accuracy
Solution Approach 2:
The echo profile is segmented into distinct regions: the leading edge portion used for accurate timing, and the peak/trailing edge portions that are excluded from measurement. This segmentation allows the system to use only the clean, undistorted leading edge data for determining echo arrival time, while ignoring the corrupted portions caused by ring-down and environmental factors
2Adaptability or versatility
If conventional echo profile analysis methods are used, then the system can handle various echo conditions, but the measurement precision deteriorates when echo amplitude is low or target is close
Solution Approach 1:
The invention applies different processing quality standards to different portions of the echo profile. The leading edge portion is processed with high precision parabola fitting to extract accurate timing information, while the peak and trailing edge portions are excluded from measurement. This local quality approach ensures that only the cleanest, most reliable signal portion contributes to the final measurement
Solution Approach 2:
The system performs preliminary identification of the leading edge start point and end point before conducting the actual measurement. This preliminary action involves detecting the valley point, calculating threshold levels, and establishing the boundaries of the leading edge region, ensuring that only appropriately selected signal portions are used for subsequent parabola fitting and timing extraction
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 improves measurement accuracy by isolating the leading edge from distortions, ensuring consistent results regardless of echo amplitude or pulse shape, and effectively differentiates between far and near ranges, thereby enhancing the precision of distance calculations in challenging environments.
Implementation Method 1
The transducer employed in an acoustic pulse-echo ranging system typically includes an electro-mechanical vibrating element that functions as both a transmitter and a receiver
Implementation Method 2
measuring how long after transmission of a pulse the echo or reflected pulse is received
Implementation Method 3
The most common mathematical method for finding the best-fitting curve, here the parabola with its parameters, to a given set of points, here the sample values of the leading edge of the echo profile, is the least-squares method
Data Source
AI summary
Pulse-echo ranging system are used in level measurement applications for determining the distance to a target object by measuring how long after transmission of a pulse an echo pulse is received. An echo profile (17) is generated and then processed to determine the temporal position of the echo pulse on a temporal axis.Based on the fact that the peak portion and the trailing edge of the echo profile are susceptible to be affected by the measurement environment and the target object itself, the accuracy in determining the echo arrival time is increased, by the steps of fitting a branch of a parabola (19) to a selected portion of the leading edge (18) of the echo profile (17) and determining the temporal position of the fitted parabola (19) on the temporal axis.