Method for high-precision distance estimation and dispersion mismatch compensation in frequency scanning interferometry

The long fiber frequency sampling method has been widely used to eliminate the nonlinearity of laser tuning in the frequency-modulated continuous wave laser ranging technique. Then, fast Fourier transform (FFT) is performed on the resampling signal to obtain the distance spectral information. However, due to the picket fence and leakage of FFT-based methods, it is hard to find the precise location and achieve better range precision. In this paper, we propose a novel frequency estimation method, multiple signal classification (MUSIC), to be used instead of the conventional fast Fourier transform (FFT)-based algorithm to obtain better range precision. In addition, the induced-fiber dispersion could also lead to poor accuracy and precision in the large-bandwidth and long-distance measurements scenes. To solve this problem, a phase compensation method for resolution-enhancement is proposed.