Chirp Sub-bottom Profiling Detailed Detection Method Based on Fractional Fourier Transform

Weak signal detection and high SNR seismic image generation are primary tasks in detailed sub-bottom profile detection. After analyzing the principle of deconvolution based on Fractional Fourier Transform (FrFT) and deriving the formula of time dimensional transformation, a new detailed sub-bottom profile detection algorithm based on FrFT is proposed. The fractional Fourier domain (u domain) sub-bottom impulse response is achieved by u domain deconvolution and the intraband SNR is increased by u domain windowed filtering technique, then high SNR envelop of u domain sediment impulse response envelop is transformed to time domain by time dimensional transformation to get high quality sub-bottom profile. Simulation and experimental data processing validate the validity of the algorithm in intraband denoising and detailed detection, and its performance is better than pulse compression and AutoRegressive (AR) forecast filtering.