Self-adaptive frequency estimation algorithm of improving liquid level measurement precision of LFMCW radar

Based on the Fast Fourier Transform(FFT) of sine signal sampling sequence, this article proposed a self - adaptive frequency estimation method using multi - spectral line information which is near the peak of spectral map. To solve the interpolation direction error of rectangular windows Rife ratio method, combining with triangular method, the new method self-adaptively selects different methods according to the different frequency. Experimental simulation results show that the new method has high estimation accuracy and small calculation amount, and is less affected by the signal - to - noise ratio (SNR), and is suitable for real - time signal processing in the low SNR.