Radar Fill Level Sensor Sampling Rate Correction
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Solution Overview
Problem
Radar-based fill-level measurement devices face accuracy issues due to inaccurate control of the sampling rate, leading to distorted measurements and reduced resolution in determining the fill level of filling materials in containers.
Innovation Solution
A method and device that generate an evaluation curve based on the relation between the clock rate and sampling rate, allowing for temporal expansion or compression of the evaluation signal to compensate for sampling rate inaccuracies, thereby improving measurement accuracy and reducing technical requirements for sampling rate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sampling rate is controlled to maintain target phase change, then measurement accuracy is improved, but device complexity increases due to slow and inaccurate control
Solution Approach 1:
The patent introduces an intermediary processing step: instead of directly controlling the sampling rate to maintain accuracy, the system measures the actual sampling rate, calculates the deviation from the target sampling rate, and uses this deviation information to correct the evaluation signal. This intermediary approach simplifies the control mechanism while maintaining measurement precision.
Solution Approach 2:
The system implements a feedback mechanism by measuring the actual sampling rate and using this information to adjust the evaluation. The control loop measures the relation between clock rate and sampling rate, then uses this feedback to correct timing deviations in the evaluation signal, thereby maintaining accuracy without requiring complex real-time control.
2Ease of operation
If the sampling rate deviates from target rate, then device operation is simpler, but measurement accuracy deteriorates due to temporal expansion or compression
Solution Approach 1:
The patent converts the harmful effect of sampling rate deviation into a useful correction factor. Instead of trying to prevent deviation, the system measures the actual deviation and uses it to calculate the necessary temporal expansion or compression of the evaluation signal. The deviation information, which would normally cause errors, is transformed into a correction parameter that restores measurement accuracy.
Solution Approach 2:
The system changes the temporal parameter of the evaluation signal based on the measured sampling rate deviation. By calculating the ratio between actual and target sampling rates, the system applies appropriate temporal expansion or compression to the evaluation signal, thereby compensating for the parameter deviation and restoring measurement accuracy.
3Productivity
If high pulse frequency is used for continuous measurement, then productivity is improved, but measurement precision deteriorates due to undersampling distortion
Solution Approach 1:
The patent introduces an intermediary correction step between undersampling and final measurement. The system measures the actual sampling rate, calculates timing deviations, and applies corrective temporal expansion or compression to the evaluation signal. This intermediary process eliminates the distortion caused by undersampling while maintaining the benefits of high pulse frequency for continuous measurement.
Solution Approach 2:
The patent replaces the mechanical approach of requiring perfectly synchronized high-frequency sampling with a signal processing approach. Instead of relying on precise mechanical timing, the system uses measured sampling rate information to mathematically correct the evaluation signal, substituting complex timing mechanics with simpler measurement and calculation.
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
The method enhances the accuracy of fill-level measurements by compensating for sampling rate deviations, allowing for more precise determination of the fill level and reducing complexity in controlling the sampling rate, while also addressing temperature dependencies and aging effects.
Implementation Method 1
reception of reflected microwave pulses after reflection at the surface of the filling material
Data Source
AI summary
Disclosed is a method for a radar-based fill level measurement according to the pulse transit time method. Also disclosed a fill level measuring device for carrying out said method. On the basis of an evaluation signal, the relation between the clock rate and the sampling rate, and a predefined target relation, an evaluation curve is generated. The fill level is thereby determined on the basis of said evaluation curve. The evaluation curve is generated by means of temporal expansion or compression of the evaluation signal, wherein the compression or the expansion is carried out as a function of a ratio between the measured relation and the target relation. Any deviation of the sampling rate from the setpoint value of the sampling rate, for example due to faulty control, is compensated. Thus, the potentially attainable accuracy of the fill level measurement is increased due to the invention.