发射脉冲波形对探地雷达响应的影响

Effect of transmitter pulse waveform on ground penetrating radar response

电性参数、系统参数以及处理方法,对探地雷达的探测深度、分辨率以及精度有重要的影响。这里主要讨论发射脉冲波形对探地雷达响应的影响,即首先产生汉宁、高斯、柯西和泊松四种窗函数所对应的发射脉冲波形,然后通过二维时域有限差分正演模拟方法分别获得上述激发波形在钢筋模型和薄层模型的响应,最后在分析响应结果的基础上,总结出不同激发波形对横向和纵向分辨率的影响。从正演模拟结果可以发现,在同一地电模型和相同的发射天线中心频率情况下,发射脉冲波形的宽度越小,其探测分辨率越高,探测深度越浅;柯西脉冲波具有较好的横向分辨率,而高斯脉冲波在横向和纵向上都具有较好的分辨率。所获得的结论对于不同地电模型的正演模拟以及探地雷达数据的解释,具有一定的指导作用。

The depth of investigation,resolution and precision of gound penetrating radar(GPR)are influenced by electrical parameters,system parameters and processing methods.This paper mainly discusses the effect of transmitter pulse waveform on GPR.Firstly,four transmitter pulse waveforms are generated by Hanning,Gaussian,Cauchy and Poisson window function,respectively.Then,we get the GPR response of rebar model and thin layer model for the above four waveforms through tow dimensional finite difference time domain forward method.At last,we analyze the GPR response results and summarize the effect of different transmitter waveforms on lateral and longitudinal resolution.The forward modeling results show that in the same cases of geo-electric model and the same antenna center frequency,the smaller the transmitter pulse waveform width,the higher the resolution,but the more shallow the depth of investigation.Cauchy pulse waveform only has better lateral resolution,while Gaussian pulse waveform can give better resolution in both lateral and longitudinal directions.The conclusions shown in this paper play aguidance role to the forward modeling of different geo-electric models and the interpretation of GPR data.