Investigation of the capability of the Compact Polarimetry mode to Reconstruct Full Polarimetry mode using RADARSAT2 data

Souissi, Boularbah; Ouarzeddine, Mounira; Belhadj-Aissa, Aichouche

doi:10.7716/aem.v1i1.12

Cited by 21 publications

(6 citation statements)

References 10 publications

(18 reference statements)

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“…Following previous studies on HCP Synthetic Aperture Radar (SAR) 4 , 14 – 18 if cross-polarization is considered negligible, i.e. are at least an order of magnitude smaller than and , which is the case for L-band forward scatter radar 40 , then the reflectivity can be approximated as: …”

Section: Methodsmentioning

confidence: 99%

“…The SMAP-Reflectometer unconventionally measures, at linear polarizations (H and V), a signal transmitted at right-hand circular polarization (RHCP) and then scattered from the Earth's surface at a mix of polarization, depending on the scattering surface itself. This is known in the SAR field as hybrid compact polarimetry (HCP) 4,[14][15][16][17][18] , but for the specific case of reflectometry, this is a full polarimetric GNSS reflectometer 19,24 . Hence, SMAP-R is the first-ever full-polarimetric GNSS reflectometer in space, as it is able to receive the full polarimetric portrait of the scene 24 .…”

Section: The Added Value Of Smap-reflectometrymentioning

confidence: 99%

“…Note that the polarimetric formulation is defined through hybrid compact polarimetry (HCP) Synthetic Aperture Radar (SAR) theory 4,[14][15][16][17][18] by computing the four Stokes parameters from the received RHCP-H and RHCP-V electromagnetic fields, as defined in the "Methods" section, and the complete SMAP-Reflectometry mathematical formulation is described in detail in 19 . From Fig.…”

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confidence: 99%

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The first polarimetric GNSS-Reflectometer instrument in space improves the SMAP mission’s sensitivity over densely vegetated areas

Rodriguez-Alvarez

Muñoz-Martín

Bosch-Lluis

et al. 2023

Sci Rep

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The Soil Moisture Active Passive (SMAP) mission has dramatically benefited our knowledge of the Earth’s surface processes. The SMAP mission was initially designed to provide complementary L-band measurements from a radiometer and a radar, producing geophysical measurements at a finer spatial resolution than the radiometer alone. Both instruments, sensitive to the geophysical parameters in the swath, provided independent measurements at different spatial resolutions. A few months after SMAP’s launch, the radar transmitter’s high-power amplifier suffered an anomaly, and the instrument could no longer return data. During recovery activities, the SMAP mission switched the radar receiver frequency facilitating the reception of Global Positioning System (GPS) signals scattered off the Earth’s surface, and enabling the radar to become the first spaceborne polarimetric Global Navigation Satellite System – Reflectometry (GNSS-R) instrument. With more than 7 years of continued measurements, SMAP GNSS-R data are the most extensive existing GNSS-R dataset and the only one providing GNSS-R polarimetric measurements. We demonstrate that the SMAP polarimetric GNSS-R reflectivity, derived from Stokes parameters mathematical formulation, can enhance the radiometer data over dense vegetation areas, recovering some of the original SMAP radar capability to contribute to the science products and pioneering the first polarimetric GNSS-R mission.

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Section: Methodsmentioning

confidence: 99%

Section: The Added Value Of Smap-reflectometrymentioning

confidence: 99%

mentioning

confidence: 99%

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The first polarimetric GNSS-Reflectometer instrument in space improves the SMAP mission’s sensitivity over densely vegetated areas

Rodriguez-Alvarez

Muñoz-Martín

Bosch-Lluis

et al. 2023

Sci Rep

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“…Although the expansion allows one to apply fully polarimetric or QP tools, the results of that approach should not be taken seriously, as they are flawed. Many publications based on the pseudo-covariance matrix approach claim superiority of FP SAR compared to HCP SAR data (e.g., [44]). All such comparisons should be discounted; they are based on faulty methodology and our recommendation is to avoid using a matrix expansion method for HCP SAR data.…”

Section: × 3 Pseudo-covariancementioning

confidence: 99%

Hybrid Compact Polarimetric SAR for Environmental Monitoring with the RADARSAT Constellation Mission

Brisco¹,

Mahdianpari

Mohammadimanesh

2020

Remote Sensing

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Canada’s successful space-based earth-observation (EO) radar program has earned widespread and expanding user acceptance following the launch of RADARSAT-1 in 1995. RADARSAT-2, launched in 2007, while providing data continuity for its predecessor’s imaging capabilities, added new polarimetric modes. Canada’s follow-up program, the RADARSAT Constellation Mission (RCM), launched in 2019, while providing continuity for its two predecessors, includes an innovative suite of polarimetric modes. In an effort to make polarimetry accessible to a wide range of operational users, RCM uses a new method called hybrid compact polarization (HCP). There are two essential elements to this approach: (1) transmit only one polarization, circular; and (2) receive two orthogonal polarizations, for which RCM uses H and V. This configuration overcomes the conventional dual and full polarimetric system limitations, which are lacking enough polarimetric information and having a small swath width, respectively. Thus, HCP data can be considered as dual-pol data, while the resulting polarimetric classifications of features in an observed scene are of comparable accuracy as those derived from the traditional fully polarimetric (FP) approach. At the same time, RCM’s HCP methodology is applicable to all imaging modes, including wide swath and ScanSAR, thus overcoming critical limitations of traditional imaging radar polarimetry for operational use. The primary image data products from an HCP radar are different from those of a traditional polarimetric radar. Because the HCP modes transmit circularly polarized signals, the data processing to extract polarimetric information requires different approaches than those used for conventional linearly polarized polarimetric data. Operational users, as well as researchers and students, are most likely to achieve disappointing results if they work with traditional polarimetric processing tools. New tools are required. Existing tutorials, older seminar notes, and reference papers are not sufficient, and if left unrevised, could succeed in discouraging further use of RCM polarimetric data. This paper is designed to provide an initial response to that need. A systematic review of studies that used HCP SAR data for environmental monitoring is also provided. Based on this review, HCP SAR data have been employed in oil spill monitoring, target detection, sea ice monitoring, agriculture, wetland classification, and other land cover applications.

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“…The relevant Hermitian covariance matrix is It should be noted that the last term can be set to zero based on the assumption of reflectional symmetry and that the covariance matrix can be simplified to In order to reconstruct the pseudo quad-polarized covariance matrix for the CP π/4 mode, S hv 2 needs to be iteratively solved. The pseudo quad-polarized covariance matrix for the π/4 mode can be expressed as [28] It is noticed that C ij in (12) is element from CP 2 × 2 covariance matrix.…”

Section: π/4mentioning

confidence: 99%

Ocean Wave Information Retrieval Using Simulated Compact Polarized SAR from Radarsat-2

Wang

Shao²,

She

et al. 2018

Journal of Sensors

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The main objective of this paper is to demonstrate the capability of compact polarized (CP) synthetic aperture radar (SAR) to retrieve ocean wave field parameters. Souyris' and Nord's algorithms are used to carry out the reconstruction of CP SAR pseudo quad-polarized data for the ocean surface under both the circular transmit linear receive (CTLR) and π/4 mode. The results show that, for the CP reconstruction, Nord's algorithm has a better convergence ability than Souyris'. In addition, the investigation of the reconstruction accuracy shows that the CTLR mode is superior to the π/4 mode, in terms of ocean surface reconstruction. It is, therefore, concluded that the reconstructed parameters of CP CTLR mode data by Nord's algorithm adapt to retrieve ocean wave information. The ocean wave slope spectrum and other main wave parameters are also calculated from reconstructed CP data and compared with measurements from in situ National Data Buoy Center (NDBC) matched-up buoys. Comparison of CP SAR-based wave field information with buoy outputs also shows good agreement in the case of dominate wave height, wave direction, and wave period, with biases of 0.36 m, 17.96°, and 0.88 s, respectively.

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Investigation of the capability of the Compact Polarimetry mode to Reconstruct Full Polarimetry mode using RADARSAT2 data

Cited by 21 publications

References 10 publications

The first polarimetric GNSS-Reflectometer instrument in space improves the SMAP mission’s sensitivity over densely vegetated areas

The first polarimetric GNSS-Reflectometer instrument in space improves the SMAP mission’s sensitivity over densely vegetated areas

Hybrid Compact Polarimetric SAR for Environmental Monitoring with the RADARSAT Constellation Mission

Ocean Wave Information Retrieval Using Simulated Compact Polarized SAR from Radarsat-2

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