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1. chinaXiv:201904.00084 [pdf]

A simulation study of GNSS-R polarimetric scattering from the bare soil surface based on the AIEM model

Subjects: Geosciences >> Geochemistry

In the past two decades, Global Navigation Satellite System-Reflectometry (GNSS-R) has emerged as a new remote sensing technique for soil moisture monitoring. Some experiments showed that the antenna of V polarization is more favorable to receive the reflected signals, and the interference pattern technique (IPT) was used for soil moisture and other geophysical parameters retrieval. Meanwhile, the lower satellite elevation angles are most impacted by the multipath. However, electromagnetic theoretical properties are not clear for GNSS-R soil moisture retrieval. In this paper, the Advanced Integral Equation Model (AIEM) is employed using the wave synthesis technique to simulate different polarimetric scattering at the specular directions. Results show when the incidence angles are larger than 70?, scattering at RR polarization (The transmitted signal is Right Hand Circular Polarization (RHCP), while the received one is also RHCP) is larger than that one at LR polarization (The transmitted signal is RHCP, while the received one is Left Hand Circular Polarization (LHCP)), while scattering at LR polarization is larger than that at RR polarization for the other incident angles(1?~70?). There is an apparent dip for VV and VR scattering due to the Brewster angle, which will result in the notch in the final receiving power and this phenomenon can be used for soil moisture retrieval or vegetation corrections. The volumetric soil moisture (vms) effects on their scattering are also presented. The larger soil moisture will result in lower scattering at RR polarization, and this is very different from the scattering of the other polarizations. It is interesting to note that the surface correlation function only affects the amplitudes of the scattering coefficients at much less level, but it has no effects on the angular trends of RR and LR polarizations.

submitted time 2019-04-10 Hits9030Downloads991 Comment 0

2. chinaXiv:201904.00085 [pdf]


吴学睿; 金双根
Subjects: Geosciences >> Geodestics


submitted time 2019-04-10 Hits7372Downloads1867 Comment 0

3. chinaXiv:201904.00086 [pdf]

GNSS-R/IR 土壤水分遥感研究现状

吴学睿; 金双根; 王峰
Subjects: Geosciences >> Geodestics


submitted time 2019-04-10 Hits4641Downloads1351 Comment 0

4. chinaXiv:201904.00074 [pdf]


Subjects: Geosciences >> Geodestics

GNSS-R/IR(GNSS-Reflectometry/Interferometric Reflectometry)遥感是利用导航卫星反射信号或直射信号与反射信号的相干信号对地观测的新兴遥感方式,在国内外引起广泛关注。为将GNSS-R/IR技术的应用领域拓展到地表冻融状态的监测上,本文利用冻融土混合介质介电常数模型计算土壤介电常数,采用双站全极化相干反射率模型和随机粗糙面散射模型, 分别计算了经冻融土反射的GPS相干反射量的镜像反射率,以及GPS非相干反射分量的漫散射特性;并模拟分析了冻融转换时,GPS多路径信息(GNSS-IR)以及包含漫散射信号的延迟多普勒图(GNSS-R)的变化特征。理论研究表明冻融转换过程中,地表介电常数的变化导致GPS多路径信息和延迟多普勒图的明显变化。本文从散射机理上揭示了利用GNSS-R和GNSS-IR遥感进行地表冻融特性监测的理论依据。

submitted time 2019-04-04 Hits4666Downloads1172 Comment 0

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