层状介质探地雷达信号Q值估计及反Q滤波

Layered Media Q Estimation for GPR Signal Processing and the Algorithm of Inverse Q Filtering

利用多层常Q模型描述层状介质探地雷达信号的衰减,并应用谱比法,通过求均方根Q值求得了层状介质每一层的Q值。将波场延拓理论应用到探地雷达信号的反Q滤波数据处理中,其步骤为:假定地下Q模型为多层常Q结构,对每个常Q层,将地表波场记录直接延拓到当前层顶部;在常Q层内对延拓后的波场在时频域采用广义S变换,对信号进行反Q滤波;对滤波结果求广义S反变换,得到反Q滤波后的时域信号。最后利用本方法对合成的3层探地雷达衰减记录和实验得到的2层探地雷达衰减记录进行了振幅和相位补偿,验证了该算法在探地雷达反Q滤波中的正确性和有效性。

Layered medium attenuation algorithm using constant Q model for ground penetrating radar（GPR） signal processing is introduced.Comparing with traditional GPR method in which it used single Q-factor to describe the attenuation of medium,moreover,the Q-factor of layered medium is determined by getting mean square root Q value using the spectral ratio method.At the same time,the step can be described as follow： the theory of wavefield downward continuation is applied to GPR signals to process the inverse Q filtering data.First,it assumes the underground Q model with multilayer constant Q structure.For each constant Q-layer,the surface wavefield records are directly extended to the top of the current layer.And then in the wavefield extended of the constant Q-layer,the signals are inverse Q filtered through generalized S transform in time-frequency domain.And then the generalized S inverse transform is done on the results of the filtering to obtain the time-domain signal of the inverse Q filtering.Finally,using this method,the amplitude and phase of three-layer GPR signals attenuation which are synthesized and two-layer GPR signals’ attenuation which are gained though test are compensated,and the result shows that the algorithm is correct and valid in inverse Q filtering of GPR signals.