The 80G radar level gauge adopts frequency modulated continuous wave (FMCW) technology. The antenna emits high-frequency frequency modulated radar signals, which are reflected by the measured medium and received by the same antenna. At the same time, the frequency difference between the transmitted signal frequency and the received signal frequency is proportional to the measured distance. The collected frequency difference signal is subjected to fast Fourier transform (FFT) to obtain the frequency spectrum of the reflected echo, and the distance of the target to be measured is calculated based on this.