FMCW Level Sensor Echo Curve Resolution Optimization
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Solution Overview
Problem
Existing level measuring devices face challenges in determining the filling level with high precision while minimizing effort, as they often require extensive signal processing and resolution adjustments to accurately identify echoes from the filling material surface and other reflections.
Innovation Solution
A method that involves converting the measurement signal into an intermediate frequency signal, sampling it, and then performing a spectral analysis to create an echo curve with varying resolutions, allowing for higher resolution calculation of specific sections of interest, such as the filling material echo, using Discrete Time Fourier Transform (DTFT) to determine additional interpolation points and refine the echo curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution echo curve calculation is performed across the entire frequency range, then measurement precision is improved, but use of energy and computational effort increase significantly
Solution Approach 1:
The patent applies local quality by calculating the echo curve with high resolution only in specific frequency ranges where echoes are expected (e.g., around the fill level echo), while using lower resolution in other frequency ranges. This selective approach maintains measurement precision for critical regions while significantly reducing overall computational energy requirements.
Solution Approach 2:
The frequency range is segmented into multiple sections, with the echo curve calculated at different resolutions for each section. The first resolution is used for the entire frequency range, while a second, higher resolution is applied only to specific sections containing echoes of interest, thereby optimizing the balance between precision and energy consumption.
2Measurement precision
If high-resolution echo curve calculation is performed across the entire frequency range, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements local quality by applying high-resolution calculation only to specific frequency sections containing relevant echoes, rather than uniformly across the entire spectrum. This reduces the complexity of signal processing while maintaining the precision needed for accurate level measurement.
Solution Approach 2:
The signal processing is segmented into different resolution levels for different frequency sections. The evaluation unit divides the frequency range and applies appropriate resolution levels based on where echoes are expected, thereby simplifying the overall processing complexity while preserving measurement accuracy.
3Measurement precision
If memory capacity is increased to store more sampling points, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies local quality by storing detailed sampling points only for frequency sections containing echoes of interest, while using fewer sampling points in other sections. This reduces memory capacity requirements while maintaining the precision necessary for accurate echo detection and level measurement.
Solution Approach 2:
The memory storage is segmented according to frequency sections, with different numbers of sampling points allocated to each section based on their importance. Critical sections containing fill level echoes receive higher resolution storage, while less important sections use lower resolution, optimizing memory usage.
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 precise determination of the filling level with reduced computational and memory demands, improving accuracy and efficiency by selectively increasing resolution only where necessary, thus optimizing resource usage in level measuring devices.
Implementation Method 1
The level gauges emit a signal towards the surface of the contents. This signal is then reflected by the surface of the contents and, if applicable, by the bottom of the container, a separating layer between different contents, or by defects in the container, and is received by the level gauge.
Implementation Method 2
which performs a spectral analysis of the measurement signal received by it as part of the level determination
Data Source
Figure 1~2B
Figure 3A~4
Figure 5
AI summary
To determine the echo curve of a level sensor operating on the FMCW principle, the echo curve is calculated from corresponding samples at a first resolution. Subsequently, a specific section of the echo curve is calculated at a second, higher resolution using the DTFT algorithm. This reduces the computational effort required to calculate the echo curve.