Chandrayaan-2双频SAR（DFSAR）：性能表征和初步结果
Chandrayaan-2 Dual-Frequency SAR (DFSAR): Performance Characterization and Initial Results
摘要：
Chandrayaan-2号航天器上的双频合成孔径雷达系统是对固体太阳系物体进行雷达探测的一个重要步骤。它在一个轻型（$\sim$ 20 kg）包装中结合了两个波长（L和S波段）的SAR和多种分辨率以及几种偏振模式。从DFSAR得到的数据支持计算的2 $\times$ 2复杂的散射矩阵为每个分辨率单元格，这使得月球近表面的特征在不同的波长和入射角的雷达极化特性。在本文中，我们报告的DFSAR数据的校准和初步性能表征的基础上分析的一组样本的月球上的陨石坑区域。我们的校准分析提供了一种手段，比较在轨性能与发射前的测量和发射前的预期值相匹配的结果。我们的初步结果表明，陨石坑在永久阴影区（PSR）和非PSR被归类为圆极化比（CPR）-异常在以前的S波段雷达分析出现异常在L波段也。我们还观察到，在其内部和近端喷出物的物质演化和物理性质是解耦的。对于Byrgius C陨石坑区域，我们将双频雷达数据的分析与理论散射模型的预测行为进行了比较。如果陨石坑的年龄估计是可用的，比较其雷达偏振特性在多个波长类似于本研究中所示的三个未命名的南极陨石坑区域，可能会提供新的见解如何陨石坑的岩石随着时间的推移而演变。
英文摘要：
The Dual-Frequency synthetic aperture radar (DFSAR) system manifested on the Chandrayaan-2 spacecraft represents a significant step forward in radar exploration of solid solar system objects. It combines SAR at two wavelengths (L- and S-bands) and multiple resolutions with several polarimetric modes in one lightweight ($\sim$ 20 kg) package. The resulting data from DFSAR support calculation of the 2$\times$2 complex scattering matrix for each resolution cell, which enables lunar near surface characterization in terms of radar polarization properties at different wavelengths and incidence angles. In this paper, we report on the calibration and preliminary performance characterization of DFSAR data based on the analysis of a sample set of crater regions on the Moon. Our calibration analysis provided a means to compare on-orbit performance with pre-launch measurements and the results matched with the pre-launch expected values. Our initial results show that craters in both permanently shadowed regions (PSRs) and non-PSRs that are classified as Circular Polarization Ratio (CPR)-anomalous in previous S-band radar analyses appear anomalous at L-band also. We also observe that material evolution and physical properties at their interior and proximal ejecta are decoupled. For Byrgius C crater region, we compare our analysis of dual-frequency radar data with the predicted behaviours of theoretical scattering models. If crater age estimates are available, comparison of their radar polarization properties at multiple wavelengths similar to that of the three unnamed south polar crater regions shown in this study may provide new insights into how the rockiness of craters evolves with time.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
