PASSIVE CALIBRATION TARGETS WITH LARGE , STABLE AND CONTROLLABLE RADAR CROSS SECTION FOR SPACEBORNE SAR
PASSIVE CALIBRATION TARGETS WITH LARGE , STABLE AND CONTROLLABLE RADAR CROSS SECTION FOR SPACEBORNE SAR
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发表时间：
2000
期刊：
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通讯作者：
A. Zakharov;P. Zherdev;M. Borisov;A. Sokolov;C. Klooster
中科院分区：
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作者：
A. Zakharov;P. Zherdev;M. Borisov;A. Sokolov;C. Klooster
1995年和1999-2000年在莫斯科附近的熊湖校准场进行了一系列ERS-1/2合成孔径雷达校准实验。从一开始，就利用了一些基于抛物面天线的新的无源校准目标的校准方案。关于散射体稳定性的研究结果和拓宽散射体方向图的设想已在前面报道过。1999-2000年的实验是在AO 3 -343项目下进行的，致力于继续研究抛物面天线散射的时间稳定性、天线方向图形状以及控制其极化特性和雷达截面的方法。实验中使用的三个抛物面天线位于具有50米腿的矩形三角形的拐角处。两个天线作为参考，另一个是一个校准目标与极化网格在焦区。极化网格的使用允许我们修改天线的散射矩阵。结果表明，改变SAR极化面与栅格极化面之间的夹角θ，可以改变目标的雷达散射截面（RCS）。AO 3 -343项目中获得的SLCI数据通常用于散射体RCS的测量。测量结果表明，参考天线具有非常稳定和非常大的~ 55 dBm的雷达截面。天线的横截面可以通过极化栅格相对于ERS-2极化平面的取向来控制。结果与理论预测和实验室测量结果吻合良好，除了正交方向，而不是20 dBm的RCS减少，我们观察到16 dBm的减少。原因是来自天线结构和极化栅格层的干扰反向散射。使用ERS合成孔径雷达数据进行的研究证实了抛物面天线的高稳定性和控制后向散射信号的极化平面（以及单极化合成孔径雷达系统的RCS）的可能性。
The series of calibration experiments with ERS-1/2 SAR were conducted in 1995 and 1999-2000 at the Bear Lakes calibration site near Moscow. Since very beginning a number of calibration scenarios with new passive calibration targets based on parabolic antennas was exploited. Some results of a study of the scatterers stability and ideas about a way to broaden scatterer pattern were reported earlier. Experiments of the year 1999-2000 were conducted under AO3-343 project and devoted to the continuation of the study of the temporal stability of parabolic antennas scattering, antenna pattern shape and a way to control their polarization properties and radar cross section. Three parabolic antennas, used in the experiment, were located at the corners of the rectangular triangle with 50 m legs. Two antennas were used as a reference, and another one was a calibration target with polarization grid in focal area. The use of the polarization grid allowed us to modify scattering matrix of the antenna. As a result, changing the angle θ between the SAR polarization plane and the grid polarization plane, we were able to change the target’s RCS for a single polarization system, like as ERS SAR. The SLCI data obtained under AO3-343 project were used usually for the measurements of the scatterers RCS. The measurements show, that reference antennas have very stable and very large ~ 55 dBm radar cross-section. The crosssection of the antenna could be controlled by the orientation of the polarization grid with respect to ERS-2 polarization plane. The results are in good agreement with theoretical predictions and laboratory measurements except for the orthogonal orientation, where instead of 20 dBm decrease of RCS we observe 16 dBm decrease only. The reason is an interfering backscatter from the antenna structure and a layer of polarization grid. The study conducted with a use of ERS SAR data confirms high stability of the parabolic antennas and the possibility to control the polarization plane (and, respectively, RCS for a single polarization SAR system) of the backscattered signal.