Assessment of PALSAR-2 Compact Non-Circularity Using Amazonian Rainforests

Touzi, R.; Shimada, Masanobu; Motohka, Takeshi; Nedelcu, S.

doi:10.1109/tgrs.2020.2983008

Cited by 9 publications

(3 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The excellent performances of the polarimetric PALSAR2 in terms of NESZ (better than −37 dB ( [1,3]) combined with the high antenna isolation permit the demonstration of the unique L-band long-penetration SAR capabilities at low incidence angles (25 • ) for subsurface peatland hydrology monitoring and discontinuous permafrost mapping [32,33]. The high isolation of the polarimetric ALOS2-PALSAR2 permits a simplification of the assessment and calibration of the ALOS2-Compact experimental mode, as discussed in [34].…”

Section: Discussionmentioning

confidence: 99%

Calibration and Validation of Polarimetric ALOS2-PALSAR2

Touzi¹,

Shimada

Motohka

2022

Remote Sensing

Self Cite

View full text Add to dashboard Cite

PALSAR2 polarimetric distortion matrix is measured using corner reflectors deployed in the Amazonian forest. The Amazonian forest near the geomagnetic equator provides ideal sites for the assessment of L-band PALSAR2 antenna parameters, at free Faraday rotation. Corner reflectors (CRs) deployed at free Faraday rotation provide accurate estimation of antenna cross-talks in contrast to the biased measurements obtained with CRs deployed at significant Faraday rotation. The extended Freeman–Van Zyl calibration method introduced and validated for ALOS-PALSAR calibration is used for the assessment of PALSAR-2 calibration parameters. Six datasets collected over the Amazonian rainforests (with CRs) are used to assess PALSAR-2 distortion matrix for five beams (FP6-3 to FP6-7) with incidence angle varying from 25° to 40°. It is shown that the PALSAR2 antenna is highly isolated with very low cross-talks (lower than −40 dB). Finally, the impact of a significant Faraday rotation on antenna cross-talk measurements using CR is discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

Calibration and Validation of Polarimetric ALOS2-PALSAR2

Touzi¹,

Shimada

Motohka

2022

Remote Sensing

Self Cite

View full text Add to dashboard Cite

show abstract

“…In actual SAR systems, the emitted electromagnetic waves are often not ideal circularly polarized waves [32]. Therefore, the influence of ellipticity distortion on the decomposition results is analyzed.…”

Section: Effect Of Transmission Distortionmentioning

confidence: 99%

General Two-Stage Model-Based Three-Component Hybrid Compact Polarimetric SAR Decomposition Method

Hou

Zhao

Liu

et al. 2021

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

View full text Add to dashboard Cite

Polarimetric decomposition is an effective way for SAR data interpretation. As for Hybrid Compact Polarimetric (HCP) SAR, there are mainly two different types of decomposition methods including wave-dichotomy-theorem-based (WDTbased) and model-based. However, the existing methods are not universal because they can not estimate volume scattering component accurately in different scenes. In order to solve this problem, a general two-stage model-based three-component HCP decomposition method (GTM) is proposed by involving Arii volume scattering model. In the first stage, a method is designed to identify the dominant scattering mechanism (surface, dihedral, and volume scattering mechanism) of each pixel according to the characteristics of the three scattering models. Then, the GTM method is solved when the three basic scattering mechanisms are dominant respectively in the second stage. Two simulated HCP data sets are used to verify the performance of the decomposition method. The results show that GTM can more accurately identify the dominant scattering mechanism in different regions than existing methods, and it can obtain closer results to the quadpolarimetric method.

show abstract

“…The shape of the antenna pattern is then clearly visible in the focused detected images. In particular, tropical rainforests, such as the Amazon and Congo forests, have been established by the SAR community as well-known test sites for SAR calibration [9]- [20], thanks to their homogeneous and almost-isotropic signature. Nevertheless, several studies conducted in C-band, e.g.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the Amazon Rainforest Backscatter at X-Band Using TanDEM-X Data

Dell'Amore,

Bueso–Bello,

Klenk

et al. 2024

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

View full text Add to dashboard Cite

The radiometric calibration of spaceborne SAR products plays a key role for ensuring a good performance of the whole end-to-end system and requires a precise knowledge of both the radar system and the illuminated target on ground. The shape of the antenna pattern in elevation can be directly estimated by analyzing SAR detected images in presence of a homogeneous and flat backscatter profile in the slant range dimension. To this aim, tropical rainforests have been established by the SAR community as well-known calibration sites for performing such an activity. Here, according to the hypothesis of isotropic scattering, the backscattering coefficient in terms of unit area perpendicular to the antenna, called gamma nought, is assumed to remain constant with respect to the incidence angle. Nevertheless, several studies using X-and C-band sensors have shown a slight dependency of the backscatter on the incidence angle, as well as on ground target properties and meteorological conditions. In this work, we present a detailed statistical characterization of radar backscatter at X-band over the Amazon rainforest using TanDEM-X data and we provide insights on how to best utilize radar backscatter data in this region for SAR calibration and modeling purposes. In particular, we concentrate on the dependency of the Amazon rainforest backscatter on the day-time of acquisition, which is directly related to the orbit direction of TanDEM-X. Furthermore, we analyze the seasonal variation of the radar backscatter, as well as possible radiation variations over different locations in the Amazon, characterized by different climate conditions and biomes. Finally, we provide a series of backscatter models for different scenarios, which can be used, e.g., for X-band spaceborne SAR system design and theoretical modeling.

show abstract

Assessment of PALSAR-2 Compact Non-Circularity Using Amazonian Rainforests

Cited by 9 publications

References 60 publications

Calibration and Validation of Polarimetric ALOS2-PALSAR2

Calibration and Validation of Polarimetric ALOS2-PALSAR2

General Two-Stage Model-Based Three-Component Hybrid Compact Polarimetric SAR Decomposition Method

Characterization of the Amazon Rainforest Backscatter at X-Band Using TanDEM-X Data

Contact Info

Product

Resources

About