FMCW Radar Distance Measurement Window Correction
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Solution Overview
Problem
FMCW radar-based distance measurement methods face accuracy issues due to frequency dependence of filling materials and internal device components, leading to systematic deviations and reduced measurement accuracy over time.
Innovation Solution
A method that generates a frequency-modulated radio-frequency signal, emits and receives radar signals, and corrects the window function based on frequency-dependent amplitude measurements using a correction factor to compensate for amplitude variations, employing a Hamming, Taylor, or Chebyshev window function to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FMCW radar-based distance measurement is performed using standard windowing, then the measurement process is simple and fast, but measurement accuracy deteriorates due to frequency-dependent amplitude variations in filling materials and device components
Solution Approach 1:
The patent applies preliminary action by performing a frequency-dependent amplitude analysis before the Fourier transform and windowing process. The method determines the amplitude of the radio-frequency signal, received signal, and evaluation signal as a function of frequency, then uses this information to correct the window function beforehand. This preliminary correction ensures that frequency-dependent amplitude variations are compensated prior to the main measurement processing, thereby improving distance measurement accuracy without significantly increasing overall process complexity.
Solution Approach 2:
The patent implements parameter changes by modifying the window function based on frequency-dependent amplitude characteristics. Instead of using a fixed standard window function, the method adjusts the window function's parameters (amplitude weights at different frequencies) according to the measured amplitude variations. This dynamic parameter adjustment compensates for frequency-dependent effects in the filling material and device components, directly improving measurement precision.
2Measurement precision
If frequency-dependent amplitude correction is applied to compensate for filling material and component influences, then measurement accuracy improves, but computational complexity and processing time increase
Solution Approach 1:
The patent applies feedback by using the determined frequency-dependent amplitude information to correct the window function. The process determines the amplitude of signals at different frequencies, uses this information to adjust the window function parameters, and then applies the corrected window function to the evaluation signal. This feedback loop ensures that the measurement system adapts to frequency-dependent variations, improving fill-level measurement accuracy while maintaining efficient processing through iterative refinement rather than exhaustive computation.
3Productivity
If standard Fourier transform with fixed windowing is used, then processing is computationally efficient, but systematic deviations occur due to frequency dependence of components
Solution Approach 1:
The patent implements dynamics by transitioning from a static, fixed window function to a dynamic, frequency-adaptive window function. The method determines amplitude variations as a function of frequency and uses this information to adjust the window function parameters dynamically. This dynamic adaptation allows the processing system to maintain computational efficiency while compensating for frequency-dependent systematic deviations, thereby improving measurement accuracy without sacrificing processing speed.
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 FMCW radar-based distance measurements by compensating for frequency-dependent influences, resulting in a more secure and precise fill-level measurement.
Implementation Method 1
Generating an electric radio-frequency signal frequency-modulated according to the FMCW principle
Implementation Method 2
Receiving the reflected radar signal as an electrical received signal after reflection on the object
Implementation Method 3
Generating an evaluation signal by mixing the received signal with the radio-frequency signal
Data Source
AI summary
Disclosed is a method and a corresponding distance-measuring device for measuring a distance to an object using FMCW radar. The method includes the frequency-dependent determination of the amplitude of the radar signal, i.e. the frequency response in the output path and in the input path of the distance-measuring device. The standard windowing of the evaluation signal can be corrected using a correction factor dependent on the frequency responses. Thus the frequency dependence of the radar signal is compensated independently of device-internal or external interferences by adapting the window function. The result is more accurate and reliable distance measurement using FMCW radar. Because the distance can be determined by the disclosed method very accurately and without distortion, it is advantageous to use the distance-measuring device as a fill-level measuring device to measure the fill level of a filling material in a container.