Land Mine Detection by Polarimetric and Interferometric Radar

(1)地表杂波和非均质土壤杂波一直是探地雷达面临的严重问题。为了减少杂波，我们提出了用阵列天线进行迁移信号处理和数据采集。(2)在人道主义排雷中，在地面上进行扫描有时是困难的，因此讨论了使用单一轨迹识别埋设目标的计量方法。在本研究中，我们证明了从单个迹线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。双基地雷达的发射机和接收机位于分开的位置。如果我们在固定位置使用发射机，并且只扫描一个小的接收器，那么探地雷达的操作会更容易。在本研究计划中，我们建议在双基地探地雷达系统中使用光电场感测器。光电场传感器是一种无源的小型传感器，适用于探地雷达系统进行人道主义排雷。我们开发了该系统，并演示了该系统可以在干沙中对埋地地雷模型进行成像。(4)先进的雷达系统应采用雷达偏振法、干涉法等新的雷达概念。用于识别的雷达偏振测量将是有用的，我们为此目的测试了天线阵列的安排。通过控制发射机和接收机的偏振状态，可以减少地面反射。我们建议在生物静态GPR系统中使用该技术。除了用于人道主义排雷的探地雷达外，我们还在各种雷达平台上测试了雷达偏振技术，包括钻孔雷达和地基SAR （GB-SAR）。(5)我们在受地雷影响的国家，包括阿富汗、埃及、克罗地亚和柬埔寨，对开发的传感器进行了评估测试。该领域的经验为传感器的进一步发展提供了有益的反馈。此外，我们可以相当清楚地了解人道主义排雷的情况和对技术的需要。

(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.