基于分FrFT的LFM浅剖包迹信号求解算法研究

Sub-Bottom Profiling Signal Envelop Calculation Algorithm Based on FrFT

LFM信号在分数阶Fourier域具有能量聚集的特性,在分数阶Fourier域对LFM信号进行滤波处理能够有效去除信号与噪声间的时频耦合,提高信号信噪比。基于分数阶Fourier变换(FrFT)对LFM浅地层冲激响应包络信号(浅剖包迹)处理技术开展理论与仿真研究。通过FrFT有效去除浅剖包迹信号与干扰噪声间的时频耦合,并提出一种基于FrFT方法的浅剖包迹信号求解方法,直接获取高信噪比的浅剖包迹图像。经过仿真研究,通过求解方法可以省略通常的FrFT步骤,直接获取信噪比较高的浅剖包迹图像。

The LFM signal has the feature of energy aggregation in the fractional Fourier domain.Filtering the LFM signal in the fractional Fourier domain can effectively remove the time-frequency coupling between the signal and the noise,and improve the signal to noise ratio.Based on the fractional Fourier transform(FrFT),research on theory and simulation of sub-bottom profiling signal envelop processing of LFM signal.The time-frequency coupling between sub-bottom profiling signal envelop and interference noise is effectively removed by FrFT,and a sub-bottom profiling signal envelop calculation algorithm based on FrFT is proposed to directly obtain high-SNR image of subbottom profiling signal envelop.After the simulation study,the usual FrFT steps can be omitted by the algorithm,and sub-bottom profiling signal envelop images with high-SNR can be obtained directly.