FMCW Radar Distance Detection Using Harmonic Phase Shift
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Solution Overview
Problem
Existing FMCW radar systems face challenges in accurately detecting distance due to limitations in filter banks and FFT methods, which are not robust against noise and surface scattering, especially when distance changes rapidly.
Innovation Solution
The method involves determining harmonics of the beat signal through Fourier decomposition and utilizing phase shift information of these harmonics to calculate the distance between the radar system and the reflecting surface, which enhances accuracy and reduces noise influence, making the method independent of surface scatter type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a filter bank or FFT is used to measure frequency difference, then measurement capability is provided, but measurement precision deteriorates due to noise and surface scattering
Solution Approach 1:
The patent changes the measurement parameter from amplitude/frequency difference to phase difference of harmonics. By using phase information instead of amplitude information, the measurement becomes robust against surface scattering and noise while maintaining high precision distance detection capability
Solution Approach 2:
The patent transitions from analyzing the fundamental beat signal to analyzing harmonic components (higher dimensions) of the beat signal. By examining phase relationships between multiple harmonics, the system achieves improved measurement precision and robustness
2Measurement precision
If amplitude relationships between harmonics are used for height detection, then detection capability is provided, but measurement precision deteriorates due to surface scattering effects
Solution Approach 1:
The patent changes the measurement parameter from amplitude to phase of harmonic components. Phase information is inherently more robust against surface scattering effects, allowing accurate height detection even when the radar reflects off surfaces with varying scattering characteristics
3Measurement precision
If multiple samples are collected and averaged to reduce noise, then measurement precision improves, but productivity deteriorates due to time delay
Solution Approach 1:
The patent uses multiple harmonic components as redundant information sources. By analyzing phase relationships between harmonics, the system achieves noise reduction without requiring temporal averaging of multiple samples, thus maintaining high detection 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 significantly improves the accuracy of distance detection, reduces noise interference, and enhances robustness against false detections by using phase shift information, allowing for precise distance measurement even under varying conditions.
Implementation Method 1
A method for detecting a distance, a radar system and a computer program product... transmitting a frequency modulated continuous wave (FMCW) radar signal from the radar system, receiving a reflected FMCW radar signal
Implementation Method 2
the step of using phase shift information of at least one of said harmonics for determining a distance between the radar system and the reflecting surface
Data Source
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AI summary
The invention relates to a method for detecting a distance between a radar system and a reflecting surface. The method comprises the steps of transmitting a frequency modulated continuous wave (FMCW) radar signal from the radar system and receiving a reflected FMCW radar signal being the transmitted signal that has been reflected by the reflecting surface. Further, the method comprises the steps of providing a beat signal having a frequency that is equal to the frequency difference between the transmitted signal and the received signal and determining harmonics of the beat signal. The method also comprises the step of using phase shift information of at least one of said harmonics for determining a distance between the radar system and the reflecting surface.