Doppler Flow Meter Sub-measurement Noise Reduction
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Solution Overview
Problem
Fluid flow measurement instruments, such as Doppler instruments, face challenges in obtaining reliable velocity measurements due to non-uniform target sizes and velocities in wastewater flows, leading to short-term noise and long-term bias, especially when bright targets dominate the signal and move at different velocities than the average fluid flow.
Innovation Solution
The implementation of a Doppler measurement instrument that produces multiple sub-measurements by dividing the measurement interval into sub-intervals, allowing for the computation of fluid flow velocity estimates using these sub-measurements, which reduces noise and bias through techniques like averaging and filtering, and optimizes energy consumption by spacing sub-measurements to minimize the impact of bright targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sub-measurements are produced and averaged to reduce noise, then measurement precision improves, but device complexity increases
Solution Approach 1:
The measurement process is divided into multiple sub-measurements taken at different time intervals within a measurement window. Each sub-measurement processes a portion of the received signal, and the results are combined through averaging. This segmentation reduces the impact of bright targets that dominate at any single moment, improving overall measurement precision while distributing the processing load.
2Reliability
If sub-measurements are spaced to minimize bright target impact, then measurement reliability improves, but measurement time increases
Solution Approach 1:
The instrument performs multiple sub-measurements at periodic time intervals within a measurement window. The spacing between sub-measurements is optimized to reduce correlation between measurements, minimizing the impact of persistent bright targets. This periodic approach improves reliability by ensuring measurements are not all corrupted by the same dominant targets, while keeping the total measurement time constrained through efficient scheduling.
3Measurement precision
If measurement window is extended to include more sub-measurements, then noise reduction improves, but energy consumption increases
Solution Approach 1:
The instrument performs a limited number of sub-measurements within a constrained measurement window, rather than continuously acquiring data. This partial action approach achieves sufficient noise reduction through averaging a moderate number of sub-measurements, while avoiding excessive energy consumption that would result from extended measurement windows or continuous processing. The measurement window is optimized to balance precision improvement against energy costs.
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 the accuracy and reliability of fluid flow velocity measurements by reducing the influence of bright targets, providing more precise estimates even in non-uniform flow conditions and extending battery life through energy-efficient sub-measurement scheduling.
Implementation Method 1
fluid flow velocity measurement instruments, for example an ultrasonic Doppler submerged A/V flow meter, use the existence of reflective targets for estimating fluid flow velocity
Implementation Method 2
a sensor producing a signal representative of reflections of an emitted signal
Data Source
AI summary
One aspect provides a fluid flow measurement instrument, comprising: a sensor producing a signal representative of reflections of an emitted signal; and a meter being coupled to the sensor and configured to: produce two or more sub-measurements from said signal representative of reflections of an emitted signal; and compute a fluid flow velocity estimate using the two or more sub-measurement signals. Other aspects are described and claimed.