探地雷达复信号分析的几点讨论

SOME DISCUSSED ABOUT REPLY SIGNAL ANALYSIS OF GPR

采用H ilbert变换的复信号分析方法,求取相位时对噪声很敏感,所以分析前的滤波处理是非常重要的,常用的反正切求取相位角方法,不利于求取包含真实反射信息的相位θ(t)。针对以上两个问题,采用了与探地雷达垂向分辨能力相关的尺度,对原始数据进行了滤波操作。滤波后的数据保证了与原始数据相同的分辨能力,有效地压制了干扰信号。同时,具有良好的数学性质,为复信号分析提供了有利的条件。利用反余弦计算相角,方便了程序设计,且求得的相角易于变换为真实相角(ω0t+θ(t)),为提取真正与反射信息相关的相位θ(t)提供了便利。应用优化方法求解瞬时相位、瞬时频率等信息,将真正与反射信息相关的θ(t)与ω0t分离,提高了分辨能力,同时还可得到ω0随时间变化的曲线,为分析探地雷达的频散现象提供了依据。

Reply signal analysis of Hilbert changing is very sensitive to the noise while computing the phase.The common method of using arctangent to compute phases is not the better way for the phase which contains the true informations of reflection.For the above two questions the yardstick correlated with vertical resolution capability is adopted in the paper to filter initial data.After filtering the data guarantee the same resolution capability as initial data,suppress the interfering signal effectively and have good mathematics nature at the same time,which offers a good condition for the analysis of replying signal.The method of using arccosine to compute phases offers the convenience to design programs.The getting phases are easy to change for the true phases,which is good for computing the phase which contains the true information of reflection.Optimizing method which is used to get informations,such as the instantaneous phase,instantaneous frequency,will be completely separated from and which are correlated with the true informations of reflection,improve resolution capability and at the same time get the curve with the changing time,which offer basis on analyzing the phenomenon of.distractive Frequency of GPR.