Research on algorithm of FMCW radar level gauge
Mengyang Li, Tao Xu, Xiaozhong Chen, Wenjie Xu · 2023
FMCW radar level gauge is widely used in industrial production. In industrial control, the FMCW radar level gauge has been used more and more widely in recent years because of its high measurement accuracy, strong anti-interference ability, convenient debugging and installation. In the FMCW radar ranging, the signal processing method used in modern FMCW radar ranging is FFT transformation, processing the difference frequency signal, calculating the difference frequency signal frequency, and obtaining the range information. The FFT algorithm can find the approximate position of the frequency signal, but not the exact frequency point. Increasing the sampling point can improve the measurement accuracy, but at the same time the calculation amount is also increased. Firstly, the composition and ranging principle of FMCW radar system are analyzed in this paper. Secondly, this paper studies the algorithms to improve the measurement accuracy of the difference frequency signal, namely chirp-z algorithm and zoomfft algorithm. After analyzing these two algorithms in detail, zoomfft algorithm is adopted. The Matlab simulation results show that the algorithm can quickly obtain the center frequency of the difference frequency signal and improve the accuracy of the ranging of the liquid level meter. Then added the CFAR analysis, the reason is that in the radar level measurement system, the liquid may be affected by the external environment to produce a splash, which will make the radar echo signal contains noise and clutter, the echo containing target information may be submerged by noise and clutter, it is difficult to detect the target information. Finally, the target information can be detected in the signal containing noise and clutter through Matlab results.