FMCW Radar Fill-Level Meter Signal Averaging
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Solution Overview
Problem
Radar-based fill-level meters using FMCW technology face challenges in accurately determining the fill level due to interference and noise, which can lead to incorrect fill-level values.
Innovation Solution
The implementation of an FMCW radar-based distance meter with an averaging stage that averages the intermediate-frequency signal over time before creating the frequency spectrum, significantly improving the signal-to-noise ratio and allowing for more reliable determination of the fill level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct filtering of the received signal is performed, then noise reduction is attempted, but the signal-to-noise ratio does not improve significantly
Solution Approach 1:
The patent applies preliminary action by performing averaging of the intermediate-frequency signal before creating the frequency spectrum. This preprocessing step prepares the signal in advance to improve the signal-to-noise ratio, allowing more reliable determination of the fill level without waiting for post-processing corrections
2Measurement precision
If averaging of frequency spectra over multiple measurement cycles is performed, then the signal-to-noise ratio improves, but trailing effects occur when process conditions change
Solution Approach 1:
The patent applies dynamics by making the averaging behavior adaptive rather than static. The system dynamically adjusts the averaging process based on detected changes in process conditions, allowing it to maintain high signal-to-noise ratio during stable conditions while quickly adapting when changes occur, thus eliminating trailing effects
3Reliability
If the FMCW radar system is used for continuous fill-level measurement, then contactless and robust measurement is achieved, but interference reflections and noise lead to incorrect fill-level values
Solution Approach 1:
The patent converts the harmful effect of noise and interference reflections into a benefit by using averaging processing. Instead of treating these disturbances as mere obstacles, the system uses statistical averaging to separate the true signal from random noise, transforming the noisy environment into an acceptable measurement condition while maintaining the robustness of contactless FMCW measurement
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 solution enhances the reliability of fill-level measurements by improving the signal-to-noise ratio, reducing the likelihood of incorrect fill-level values, and minimizing trailing effects.
Implementation Method 1
Radar-based measuring methods are therefore predominantly used in the field of continuous fill-level measurement (in the context of this patent application, the term 'radar' refers to signals or electromagnetic waves with frequencies between 0.03 GHz and 300 GHz)
Implementation Method 2
After reflection on the surface of the filling material, the corresponding received signal is mixed by signaling technology with the generated radar signal
Implementation Method 3
the corresponding received signal is mixed by signaling technology with the generated radar signal in order to obtain a low-frequency intermediate-frequency signal
Implementation Method 4
the evaluation unit is characterized by an averaging stage designed to average the intermediate-frequency signal in the signal direction over time before the frequency spectrum is created. This allows the signal-to-noise ratio to be significantly improved
Implementation Method 5
In order to ascertain the frequency of the intermediate-frequency signal in order to determine the fill level, the intermediate-frequency signal is subsequently converted into a frequency spectrum by Fourier transform
Data Source
AI summary
The invention relates to an FMCW radar-based distance meter by means of which the distance to an object can be reliably determined. The distance meter comprises at least: a signal generation unit for generating corresponding high-frequency signals; an HF antenna for transmitting and receiving the radar signals; and an evaluation unit typical for FMCW. The evaluation unit includes an additional averaging stage that averages the intermediate-frequency signal in the signal direction over time before the frequency spectrum is created. This significantly improves the signal-to-noise ratio of the intermediate-frequency signal. Overall, the correct maximum in the frequency spectrum, said maximum representing the distance, can thus be determined in a significantly more reliable manner.