全球导航卫星系统反射测量技术（GNSS-R）是一种通过解析导航卫星反射信号实现地表参数反演的有效对地观测手段。已有研究表明，传统GNSS-R系统主要采用单一极化配置［右旋圆极化（RHCP）发射与左旋圆极化（LHCP）接收，简称LR极化］，对其他极化组合的散射特性研究相对薄弱。随着技术进步，采用RHCP 天线接收地表反射信号的方案逐渐受到重视。同时，传统GNSS-R的时延—多普勒图（DDM）处理模式在不同观测几何条件下对散射特征的利用效率较低。在此背景下，发展能够跨几何构型有效接收地表散射信号的GNSS 合成孔径雷达（GNSS-SAR）技术成为具有潜力的研究方向。通过聚焦简缩极化GNSS-R 与合成孔径雷达融合技术（GNSSReSAR）的遥感探索，基于西班牙机载GLORI 实验获取的双极化［LR（RHCP 发射与LHCP 接收）及RR（RHCP 发射与RHCP 接收）］数据开展了土壤水分反演研究，并同步利用中国天目（TM）商业卫星的双极化GNSS-R 数据进行对比验证。两项实验一致表明，RR 极化反射率较LR 极化低约10 dB，但基于两种极化反演的土壤水分精度具有可比性。受限于简缩极化数据获取能力，采用基于辐射传输理论构建的LAGRS 模型解析简缩极化的其他散射特性。通过系统分析GNSS-ReSAR模式的散射机制与发展趋势，为新一代GNSS-R技术演进在一定程度上提供了理论参考。

Abstract：Global Navigation Satellite System Reflectometry (GNSS-R) is an effective Earth observation method that uses the analysis of navigation satellite reflection signals to invert surface parameters. Historical research has shown that traditional GNSS-R systems mainly adopt a single polarization configuration (righthanded circularly polarized (RHCP) transmission and left-handed circularly polarized (LHCP) reception, hereinafter referred to as LR polarization), and the study of scattering characteristics of other polarization combinations is relatively weak. With the advancement of technology, the scheme of using RHCP antenna to receive surface reflection signals has gradually gained attention. Meanwhile, the traditional Delay Doppler Map (DDM) processing mode of GNSS-R has low efficiency in utilizing scattering features under different observation geometries. In this context, the development of GNSS based Synthetic Aperture Radar (GNSS-SAR) technology that can effectively receive surface scattering signals across geometric configurations has become a promising research direction. This study focuses on the remote sensing exploration of the fusion technology of reduced polarization GNSS-R and synthetic aperture radar (GNSS ReSAR: GNSS Reflectometry and Synthetic Aperture Radar). Based on the dual polarization (LR and RR (RHCP launch and RHCP reception) data obtained from the Spanish airborne GLORI experiment, soil moisture inversion research was carried out, and the dual polarization GNSS-R data from the Chinese Tianmu (TM) commercial satellite was synchronously used for comparative verification. Both experiments consistently showed that the reflectance of RR polarization was about 10 dB lower than that of LR polarization, but the accuracy of soil moisture inversion based on the two polarizations was comparable. Due to the limited ability to obtain simplified polarization data, this study uses the LAGRS (Land Surface GNSS Reflection Simulator) model constructed based on radiative transfer theory to analyze other scattering characteristics of simplified polarization. By systematically analyzing the scattering mechanism and development trend of GNSS ReSAR mode, it provides theoretical reference for the evolution of the new generation GNSS-R technology to a certain extent.