A novel algorithm in the FMCW microwave liquid level measuring system

The structure of a frequency modulated continuous wave (FMCW) microwave liquid level radar system was introduced and the FMCW radar ranging principle was discussed. A fast frequency estimation algorithm (FFEA) based on fast Fourier transform (FFT) technique, which can achieve high ranging accuracy and better computational efficiency, was proposed to obtain the distance information from the radar echo signal. The high-speed signal processor DSP is suitable for the real-time signal processing, and can be used to linearize the frequency sweep of VCO. The simulation results indicated that FFEA owned high accuracy as compared with the FFT method and required much less computational load as compared with zoom FFT.