多输入多输出极化步进频率探地雷达硬件系统开发

Development of Multiple-Input and Multiple-Output Polarimetric Stepped-Frequency Ground Penetrating Radar System

对基于矢量网络分析仪的单发单收探地雷达系统进行扩展,组建了可实现信号多通道发射和多通道接收的步进频率探地雷达系统。该系统主要由计算机、矢量网络分析仪、三维直角坐标仪、开关控制转换器、同轴开关以及多次覆盖极化天线阵列构成。系统信号发射通道和信号接收通道均可扩展至6个通道,可满足一般天线阵列测量需求。多次覆盖天线阵列采集共中心点(CMP)数据,每个测点可获取2个共极化模式数据和4个交叉极化模式数据,数据叠加后噪声可得到有效压制,系统信噪比可获得较大提升;同时应用Pauli分解方法获得伪彩色剖面图以对目标物体进行散射机制的分类。对该多输入多输出步进频率探地雷达系统进行系统测试和实验的结果,验证了其可靠性。

conventional GPR system includes computer,network analyzer,rectangular coordinate robot,and a single antenna mode for transmission and reception,responding only to the co-polarization signal.However,we expect that more polarmetric information can be obtained.So we developed a full-polarimetric GPR system including computer,vector network analyzer,position controller,switch driver,and polarimetric multiple coverage antenna array.The arrangement of the antenna array consists of ten Vivaldi antennas oriented perpendicularly to each other that can obtain co-polarization and cross-polarization signals for each transmission.One group of experiment was performed.This group targeted to a metallic plate and a metallic dihedral.The result of this experiment shows that this GPR system with the proposed antenna array is capable of detecting the existence of buried targets,and the application of the polarimetric multiple coverage antenna array can improve the signal-to-noise ratio dramatically.We use Pauli polarimetric decomposition technique to obtain subsurface colour-coded reconstructed object images,which can be employed to interpret both the geometrical information and the scattering mechanism of the subsurface objects.