Compared with microwave and millimeter-wave

Terahertz radar is easy to realize high distance measurement precision due to short wavelength and wide bandwidth.It adopts frequency modulated continuous wave radar

in the process of spectral analysis of beat signal

the spectrum leakage and fence effect have impact on distance measurement precision.By adjusting sampling parameter to realize integral period sampling reduce spectrum leakage

and central frequency of peak spectral frequency is estimated by the gradient method which is made up of peak spectral line and adjacent spectral lines

reduces error caused by discrete spectrum interval.The precision is improved by two steps correction.Experimental results indicate that error of measurement precision of proposed algorithm is reduced compared with traditional frequency estimation method

precision of proposed method is increased by an average of 58.5 % compared with FFT.