PolSAR calibration and reconstruction of hybrid polarimetric RISAT-1 data for pseudo quad-pol decomposition: a comparison with quad-pol

Kumar, Shashi; Gupta, Vivek K.; Gonnuru, Pratyusha; Joshi, Sushil Kumar

doi:10.1117/12.2225425

Cited by 3 publications

(3 citation statements)

References 3 publications

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“…This is a process of quantitatively defining the sensor responses to a controlled signal. The backscattered coefficient σ 0 is retrieved through DN values during the process of radiometric calibration [36]. This is implemented using the methodologies given in the past literatures [37]- [39].…”

Section: Methodology Implementationmentioning

confidence: 99%

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Snow Density retrieval using Hybrid polarimetric RISAT-1 datasets

Awasthi

Thakur

Kumar

et al. 2020

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

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Retrieval of snow density using hybrid polarimetric RISAT-1 synthetic aperture radar (SAR) data is implemented in this study. The C-band datasets were acquired in the fine resolution stripmap mode-1 (FRS-1) in which microwaves EM are transmitted in the right circular polarization from the sensor and are received in linear (horizontal or vertical) polarizations resulting in hybrid polarizations-RH and RV. The datasets were acquired for the date of February 23, 2014 covering the Dhundi region in Manali district of Himachal Pradesh. In this season, the area experiences regular snowfall, hence the whole area was covered with the dry snow layer. Hybrid decomposition technique along with the integral equation model (IEM) is utilized for snow density extraction of the snowpack in the study area. The modeled and theoretical approaches are used to retrieve the dielectric constant of the snowpack. Fresnel coefficients, utilized in the IEM modeling approach, are the function of snowpack dielectric constant and the local incidence angle of the incident wave from the sensor. The retrieved snow density map is generated for the area. The validation of the retrieved results is done using ground data collected during the period.

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Section: Methodology Implementationmentioning

confidence: 99%

“…Also, it is independent of the polarization basis. Many other studies based on compact polarimetry have also used these parameters for various applications [36], [41]- [43].…”

Section: ) Theoretical Alpha Parameter Calculationmentioning

confidence: 99%

Snow Density retrieval using Hybrid polarimetric RISAT-1 datasets

Awasthi

Thakur

Kumar

et al. 2020

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

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“…The polarimetric SAR data is useful in understanding the different scattering mechanisms happening on the Earth's surface from different types of targets using the phase and amplitude information from the different polarization channels data with the help of polarimetric decomposition and classification techniques [5]. However, the polarimetric distortion in the Polarimetric Synthetic Aperture Radar (PolSAR) datasets causes the polarimetric decomposition and classification techniques to produce wrong outputs, which result in misinterpreting of the scattering phenomenon and ground targets.…”

Section: Introductionmentioning

confidence: 99%

RISAT-1 Compact Polarimetric Calibration and Decomposition

Babu

Kumar

Agrawal

2019

3rd International Electronic Conference on Remote Sensing

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Indian Space Research Organisation’s Radar Imaging Satellite (RISAT) -1 was the first Synthetic Aperture Radar (SAR) satellite equipped with the compact polarimetric (CP) mode for data acquisition. To exploit the advantages offered by the CP mode, the datasets need to be polarimetrically calibrated. The polarimetric calibration procedure estimates the polarimetric distortions in the datasets caused due to channel imbalance, crosstalk, and Faraday rotation. These polarimetric distortions cause the misinterpretation of the ground targets in the polarimetric decomposition techniques. The Freeman compact-pol polarimetric calibration algorithm is the most commonly used algorithm. In this study, the RISAT-1 Circular Transmit Linear Receive (CTLR) dataset of the RISAT Cal Val site was used to estimate the polarimetric distortion parameters and these distortion parameters were used to polarimetrically calibrate the RISAT-1 CTLR dataset of the Doon Valley region, Uttarakhand, India. The Cloude compact-pol decomposition algorithm was used to evaluate the ground target characterization accuracy before and after polarimetric calibration using the Freeman compact-pol polarimetric calibration algorithm. Before polarimetric calibration, urban targets were showing surface scattering behavior and river channels were showing increased double-bounce scattering behavior. After polarimetric calibration, the urban targets showed dominance in double-bounce scattering and river channels showed dominance in surface scattering as per the theory.

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