Land Mine Detection by Polarimetric and Interferometric Radar

(1)地表杂波和土壤不均匀杂波一直是探地雷达面临的严重问题。为了减少杂波，本文提出了利用阵列天线进行偏移信号处理和数据采集的方法。(2)在人道主义排雷中，地面扫描有时很困难，讨论了利用单一轨迹识别埋藏目标的方法。在本研究中，我们论证了从单个航迹的时频表示中提取目标特征是可行的，并给出了实验室测试结果。(3)双基地雷达将发射机和接收机分别放置在不同的位置。如果我们在固定位置使用发射机，并且只扫描一个小接收器，那么探地雷达的操作就会更容易。在本研究项目中，我们提出在双基地探地雷达系统中使用光电场传感器。光电场传感器是一种无源的小型传感器，适用于人道主义排雷的探地雷达系统。我们研制了该系统，并演示了该系统可以对干沙中埋藏的地雷模型进行成像。(4)先进的雷达系统应采用雷达极化和干涉测量等新的雷达概念。雷达偏振测量用于识别将是有用的，我们为此测试了天线阵列的布置。通过控制发射器和接收器的偏振状态，可以减少来自地面的反射。除了用于人道主义排雷的探地雷达外，我们还在包括钻孔雷达和地面合成孔径雷达(GB-SAR)在内的各种雷达平台上测试了雷达极化技术。(5)我们在阿富汗、埃及、克罗地亚和柬埔寨等受地雷影响的国家进行了评估测试。现场的经验对传感器的进一步发展是非常有用的反馈。此外，我们可以非常清楚地了解人道主义排雷的情况和对技术的需求。

(1)Clutter due to ground surface and inhomogeneous soil always is always serious problem for GPR. In order to reduce the clutter, we proposed migration signal processing and data acquisition by an array antenna.(2)In humanitarian demining, scanning on the ground surface is sometimes difficult and metrologies to use a single trace for identification of buried targets were discussed. In this study we demonstrated extracting target features from Time-frequency representation of a single trace can be sued, and laboratory test results were shown.(3)A bistatic radars have the transmitter and the receiver at separated positions. If we use a transmitter at fixed position, and only a small receiver is scanned, the operation of GPR can be easier. We propose in this research project to use an optical electric field sensor for the bistatic GPR system. an optical electric field sensor is a passive, small sensor and it fits to GPR systems for humanitarian demining. WE developed the systems, and demonstrated the system can image buried landmine models in dry sand.(4)New radar concept such as radar polarimetry and interferometry should be adopted for advanced radar systems. Radar polarimetry for identification will be useful, and we tested arrangements of antenna arrays for this purpose. The reflection from the ground surface can be reduced by controlling the polarization status of the transmitter and receiver. We propose to use this technique in the biostatic GPR system.In addition to the GPR for humanitarian demining, we tested radar polarimetry technique to various radar platforms including borehole radar and Ground-Based SAR (GB-SAR).(5)We conducted evaluation tests of the developed sensor in mine affected courtiers including Afghanistan, Egypt, Croatia and Cambodia. The experience in the field is quite useful feedback for further development of the sensor. Also, we could understand the situation of the humanitarian demining and needs for technologies quite clearly.