FMCW Radar Dispersion Correction in Pipes
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Solution Overview
Problem
Radar measurement accuracy in pipes or tubes is compromised due to dispersion effects caused by the frequency-dependent propagation velocity of radar waves, leading to smearing and divergence of the reflected signal, which complicates the evaluation of distance measurements.
Innovation Solution
A radar measurement apparatus using the FMCW principle with a phase correction mechanism that lessens or eliminates dispersion-dependent phase fractions and adds a non-dispersive phase fraction linearly rising with time, allowing for sharper frequency peaks and improved evaluation of target frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If radar waves are transmitted through a pipe or tube, then the radar measurement apparatus can measure distance in confined spaces, but dispersion effects cause frequency-dependent propagation velocity leading to signal smearing and divergence
Solution Approach 1:
The patent applies parameter changes by introducing a phase correction mechanism that adjusts the phase of the intermediate frequency signal to compensate for dispersion effects. The correction involves changing the phase parameter dynamically based on the frequency content of the signal, thereby restoring measurement precision while maintaining the ability to measure in confined pipe or tube spaces.
Solution Approach 2:
The patent converts the harmful dispersion effects into a manageable parameter by measuring the phase distortion caused by dispersion and using it to calculate a correction factor. The harm of frequency-dependent propagation is transformed into a correctable phase error, allowing the system to maintain both confined space capability and measurement precision.
2Device complexity
If no phase correction is applied, then the device complexity remains low, but frequency peaks become broadened and distanced, complicating signal evaluation
Solution Approach 1:
The patent applies preliminary action by performing phase correction on the intermediate frequency signal before conducting the final distance measurement and frequency analysis. This preliminary processing step sharpens the frequency peaks and eliminates distortion, making the subsequent detection and measurement processes simpler and more accurate, thereby reducing the overall difficulty of signal evaluation.
3Device complexity
If dispersion effects are not corrected, then the measurement system remains simple, but the reflected signal becomes smeared and divergent, reducing measurement accuracy
Solution Approach 1:
The patent implements feedback by continuously monitoring the phase of the intermediate frequency signal and applying corrective phase shifts to compensate for dispersion. The system measures the actual phase distortion caused by the pipe or tube and uses this feedback information to adjust the signal, thereby maintaining high measurement precision without excessive complexity.
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 phase correction significantly enhances the accuracy of distance measurements by reducing the broadening and distancing of frequency peaks, enabling more precise evaluation of the intermediate frequency signal and improving the accuracy of fill level measurements in pipes or tubes.
Implementation Method 1
a radar transmission unit (203) which is designed to produce a radar transmission signal (213), which is frequency modulated according to the FMCW principle
Implementation Method 2
a radar receiving unit (205) which is designed to receive a radar received signal (214) reflected on the surface of the medium (101) back in the pipe or tube (102), to convert the radar received signal (214) by mixing with the radar transmission signal (213), or a signal derived therefrom, into an intermediate frequency signal (209)
Implementation Method 3
The radar receiving unit is designed to apply a phase correction to the phase of the intermediate signal and to produce a phase corrected intermediate frequency signal, wherein the phase correction is designed to lessening or to remove a dispersion dependent phase fraction in the phase of the intermediate signal
Data Source
AI summary
A radar measurement apparatus works according to the FMCW principle and includes a radar transmission unit, and a radar receiving unit, which is designed to receive a radar received signal reflected on a surface of the medium or other target in a pipe or tube, to convert the received signal into an intermediate frequency signal by mixing with the transmission signal, or a signal derived therefrom, and based on an intermediate signal to determine distance to the surface of the medium or other target. The radar receiving unit applies a phase correction to the intermediate signal produces a phase corrected, intermediate frequency signal, wherein the phase correction lessens or removes a dispersion dependent phase fraction in the phase of the intermediate signal and adds a non-dispersion effects dependent phase fraction. The radar receiving unit is designed based on the phase corrected intermediate signal to determine the target frequency components in the intermediate frequency signal and based on the target frequency components to determine distance to the surface of the medium or other radar.