Signal Segmentation for Radar Fill Level Measurement
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Solution Overview
Problem
Fill level measurement devices using travel time principles face challenges in distinguishing between desired and undesired reflections, especially when physical properties of the medium are unknown or changing, leading to inaccurate fill level determination.
Innovation Solution
A method that involves obtaining reference signal data to differentiate between interference and useful signals by comparing measurement curves with known data, using signal characteristics like amplitude, phase, and time displacement to determine the fill level without exact knowledge of the medium's physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the measurement device receives all reflected signals including interference signals, then the device can obtain additional information about the fill material and device condition, but the useful signals from the fill material surface cannot be unequivocally identified
Solution Approach 1:
The patent segments the measurement signals by comparing the measurement curve with reference signal data to distinguish between useful signals (from fill material surface) and interference signals (from container walls, objects, or geometry). This segmentation allows separate evaluation of different signal components, enabling both accurate fill level measurement and extraction of additional fill material information from interference signals without confusion between signal sources.
2Measurement precision
If the device uses signal evaluation methods that assume accurate knowledge of dielectric constant and magnetic permeability, then the fill level can be determined from floor signals, but these physical properties are not always known and can change
Solution Approach 1:
The patent performs preliminary action by obtaining reference signal data before evaluating measurement signals. These reference data are obtained either from previous measurements or from known measurement device and container geometry. By having reference data available in advance, the system can compare current measurement curves against these references to identify useful and interference signals without needing to assume specific values for dielectric constant or magnetic permeability, thus adapting to different media without requiring prior knowledge of their physical properties.
3Reliability
If polarization devices are used to change the polarization plane of signals, then the intensity of interference reflection at interference locations can be changed, but this increases device complexity and cost
Solution Approach 1:
The patent uses feedback by comparing measurement curves with reference signal data to identify and evaluate interference signals. The system continuously monitors the measurement signals, compares them against known reference patterns, and uses this comparison feedback to distinguish useful signals from interference signals. This feedback mechanism allows the system to manage interference signals effectively without requiring additional hardware components like polarization devices, thereby maintaining device simplicity while achieving reliable signal differentiation.
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 enhances the accuracy and reliability of fill level measurement, providing additional information about the fill material and measurement device condition, even when direct fill level signals are not identifiable, and allows for fill level estimation using interference signals.
Implementation Method 1
high frequency signals, ultrasonic signals or optical signals generated in the fill level measurement device are sent from the measurement device in the direction onto the medium, where they are reflected at a surface of the medium
Implementation Method 2
Their travel time is a measure for the distance of the measurement device from the reflecting surface of the medium
Implementation Method 3
fill level measurement devices which work with microwave- or radar-measurement signals, wherein the radar signals are radiated from an antenna freely onto the medium and can be received as they come back from there
Implementation Method 4
Other fill level measurement devices with radar measurement signals are, for example, those in which the radar measurement signals are guided by a waveguide extending into the fill material
Data Source
AI summary
A method which allows especially the extrapolation of the measured value at the upper and lower end of a measuring range where normally no direct measurement range where normally no direct measurement is possible by superposition of interfering signals, for example by reflection on a radar antenna. In the presence of strong interference signals, for example by reflection of a radar antenna. In the presence of strong interference signals, which are for example caused by the natural resonance of the container or neck in which the measuring device is mounted, the direct level indicator signal can be regularly used if it has a high amplitude caused by a superposition with the interfering signal lies between two interfering signals and does not extend beyond these, the level indicator value can be interpolated by the shift of the signals from the point of reflection. The inventive method automatically adapts itself to a prevailing measuring situation while according to known methods for the user has to decide between a measurement via a shift of EOL signal or a measurement via the direct level indicator echo.