scholarly journals A Novel Weighted Amplitude Modulation (WAM) System for Ambiguity Suppression of Spaceborne Hybrid Quad-Pol SAR

2021 ◽  
Vol 14 (1) ◽  
pp. 155
Author(s):  
Yanyan Zhang ◽  
Sheng Chang ◽  
Robert Wang ◽  
Peng Li ◽  
Yongwei Zhang ◽  
...  
Keyword(s):  
Amplitude Modulation ◽  
Band System ◽  
Synthetic Aperture ◽  
Moving Target ◽  
Polarimetric Synthetic Aperture Radar ◽  
Climate Zones ◽  
System Parameters ◽  
Range Ambiguity ◽  
L Band ◽  
Chirp Scaling Algorithm

Quadrature-polarimetric synthetic aperture radar (quad-pol SAR) has extensive applications, including climate zones classification, extraction of surface roughness, soil moisture mapping, moving target indication, and rice mapping. Hybrid quad-pol SAR ameliorates the range ambiguity performance of conventional quad-pol SAR. However, the azimuth ambiguity of its cross-polarized (cross-pol) echo signals is serious, limiting the swath width of SAR. Therefore, this paper proposes a spaceborne weighted amplitude modulation (WAM) full-polarimetric (full-pol) SAR system, and it can suppress the azimuth ambiguity of hybrid quad-pol SAR. The performance boost of the azimuth ambiguity by the two imaging modes of the proposed SAR system is detailed and evaluated with the L-band system parameters. Moreover, the chirp scaling algorithm (CSA) is adopted to execute scene simulations for the two imaging modes. The results indicate that the proposed SAR system can effectively suppress the azimuth ambiguity of hybrid quad-pol SAR and verify the theoretical analysis.

scholarly journals Comparative Analysis of Polarimetric SAR Calibration Methods

2018 ◽  
Vol 10 (12) ◽  
pp. 2060 ◽  
Author(s):  
Yoon Jung ◽  
Sang-Eun Park
Keyword(s):  
Comparative Analysis ◽  
Calibration Method ◽  
System Model ◽  
Synthetic Aperture ◽  
Polarimetric Sar ◽  
Alos Palsar ◽  
Polarimetric Synthetic Aperture Radar ◽  
System Parameters ◽  
Calibration Methods ◽  
Polarimetric Calibration

In the diverse applications of polarimetric Synthetic Aperture Radar (SAR) systems, it is a crucial to conduct polarimetric calibration, which aims to remove the radar system distortion effects prior to utilizing polarimetric SAR observations. The objective of this study is to evaluate the performance of different polarimetric calibration methods. Two widely used methods, the Van Zyl and Quegan methods, and one recently proposed method, such as the Villa method, have been selected among various calibration methods in literature. The selected methods have basic differences in their assumptions that are applied to the polarimetric system model. In order to evaluate the calibration performances under different system parameters and ground characteristics, comparative analysis of the calibration results were conducted on synthetic polarimetric SAR data and ALOS PALSAR quad-pol mode data. Based on the experimental results, the advantages and limitations of different methods were clarified, and a simple hybrid calibration method is presented to further improve the polarimetric calibration performance.

scholarly journals Azimuth Ambiguity Suppression for Hybrid Polarimetric Synthetic Aperture Radar via Waveform Diversity

2020 ◽  
Vol 12 (7) ◽  
pp. 1226
Author(s):  
Pengfei Zhao ◽  
Yunkai Deng ◽  
Wei Wang ◽  
Dacheng Liu ◽  
Robert Wang
Keyword(s):  
Synthetic Aperture Radar ◽  
System Structure ◽  
Synthetic Aperture ◽  
Potential Candidate ◽  
Post Processing ◽  
Polarimetric Synthetic Aperture Radar ◽  
Range Ambiguity ◽  
Waveform Diversity ◽  
Target Detecting ◽  
Aperture Radar

Hybrid quadrature polarimetric (hybrid quad-pol) synthetic aperture radar (SAR) is proposed as a potential candidate for the full-polarimetric SAR mode. It allows balanced range ambiguity performance and simplified system structure. System based on hybrid-pol SAR mode can also implement the conventional quad-pol mode and the compact-pol mode via few adjustments. However, the azimuth ambiguity performance in cross-pol channels is proved deteriorated in hybrid quad-pol mode due to the lopsided energy distribution of ambiguities. As are generally called “ghost” targets, azimuth ambiguities usually influence the recognition of the targets in SAR imaging. This letter describes how to remove the false targets that arise from azimuth ambiguities by means of waveform diversity and dual-focus post-processing (DFPP) technique. The proposed method exploits the feature of azimuth ambiguity and yields improved image quality in cross-pol channels with strong co-pol azimuth ambiguities removed in hybrid quad-pol SAR at a low system cost. Furthermore, it offers remarkable benefits for target detecting and recognition with strong false targets removed.

scholarly journals Performance Analysis of Ocean Eddy Detection and Identification by L-Band Compact Polarimetric Synthetic Aperture Radar

2021 ◽  
Vol 13 (23) ◽  
pp. 4905
Author(s):  
Sijing Shu ◽  
Ji Yang ◽  
Chuanxun Yang ◽  
Hongda Hu ◽  
Wenlong Jing ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Shannon Entropy ◽  
Synthetic Aperture ◽  
Stokes Parameters ◽  
Polarization Degree ◽  
Polarimetric Synthetic Aperture Radar ◽  
Ocean Eddies ◽  
L Band ◽  
Eddy Detection ◽  
Aperture Radar

The automatic detection and analysis of ocean eddies has become a popular research topic in physical oceanography during the last few decades. Compact polarimetric synthetic aperture radar (CP SAR), an emerging polarimetric SAR system, can simultaneously acquire richer polarization information of the target and achieve large bandwidth observations. It has inherent advantages in ocean observation and is bound to become an ideal data source for ocean eddy observation and research. In this study, we simulated the CP data with L-band ALOS PALSAR fully polarimetric data. We assessed the detection and classification potential of ocean eddies from CP SAR by analyzing 50 CP features for 2 types of ocean eddies (“black”and “white”) based on the Euclidean distance and further carried out eddy detection and eddy information extraction experiments. The results showed that among the 50 CP features, the dihedral component power (Pd), shannon entropy (SEI), double bounce (Dbl), Stokes parameters (g0 and g3), eigenvalue (l1), lambda, RVoG parameter (ms), shannon entropy (SE), surface scattering component (Ps), and σHH all performed better for detecting “white” eddies. Moreover, the H-A combination parameter (1mHA), entropy, shannon entropy (SEP, SEI, and SE), probability (p2), polarization degree (m), anisotropy, probability (p1), double bounce (Dbl), H-A combination parameter (H1mA), circular polarization ratio (CPR), and σVV were better CP features for detecting “black” eddies.

scholarly journals Novel Techniques for Built-Up Area Extraction from Polarimetric SAR Images

2020 ◽  
Author(s):  
D Ratha ◽  
P Gamba ◽  
A Bhattacharya ◽  
Alejandro Frery
Keyword(s):  
Remote Sensing ◽  
Unit Sphere ◽  
Geodesic Distance ◽  
Synthetic Aperture ◽  
Extraction Techniques ◽  
Remote Sensing Images ◽  
Sar Images ◽  
Polarimetric Synthetic Aperture Radar ◽  
Urban Scenes ◽  
L Band

© 2004-2012 IEEE. Built-up (BU) area extraction from remote sensing images is important to monitor and manage urbanization and industrialization. In this letter, we propose two BU area extraction techniques based on the analysis of fully polarimetric synthetic aperture radar (PolSAR) data. Both methods exploit the geodesic distance on the unit sphere in the space of Kennaugh matrices. The first method is based on the three dominant scattering types in the scene and compares them with scattering models; if any of them matches with BU type elementary scattering models, then the pixel is said to belong to a BU area. The second method is based on a novel PolSAR BU index (RBUI) composed by considering scattering mechanisms from BU structures. The two proposed techniques are validated on two different urban scenes, one acquired at C-band by RADARSAT-2 and other at L-band by ALOS-2 SAR sensors.

scholarly journals FULL POLARIMETRIC UAVSAR IMAGE CHANGE DETECTION BASED ON CHANGE INDICES

2019 ◽  
Vol XLII-4/W18 ◽  
pp. 1107-1111
Author(s):  
L. Yousefizadeh ◽  
R. Shahhoseini ◽  
S. Homayouni
Keyword(s):  
Change Detection ◽  
Detection Method ◽  
Synthetic Aperture ◽  
Sar Images ◽  
Polarimetric Synthetic Aperture Radar ◽  
San Andreas ◽  
L Band ◽  
Image Change Detection ◽  
Dimension Space ◽  
Change Detection Performance

Abstract. Change detection is one of the most important applications of Polarimetric Synthetic Aperture Radar (PolSAR) data in monitoring urban development and supporting urban planning due to the sensibility of SAR signal to geometrical and physical properties of terrestrial features. In this paper, we proposed an unsupervised change detection method using change indices extracted from PolSAR images. Kernel k-means clustering was then performed to extract changed areas. The kernel k-means clustering is an unsupervised algorithm that maps the input features to higher Hilbert dimension space by using a kernel function. To better representation of changed areas, different change indices were generated. The method was applied to UAVSAR L-band SAR images acquired over an urban area in San Andreas, United States. We evaluated the change detection performance based on kappa and overall accuracies of the proposed approach and compared with other well-known classic methods.

scholarly journals Novel Techniques for Built-Up Area Extraction from Polarimetric SAR Images

2020 ◽  
Author(s):  
D Ratha ◽  
P Gamba ◽  
A Bhattacharya ◽  
Alejandro Frery
Keyword(s):  
Remote Sensing ◽  
Unit Sphere ◽  
Geodesic Distance ◽  
Synthetic Aperture ◽  
Extraction Techniques ◽  
Remote Sensing Images ◽  
Sar Images ◽  
Polarimetric Synthetic Aperture Radar ◽  
Urban Scenes ◽  
L Band

© 2004-2012 IEEE. Built-up (BU) area extraction from remote sensing images is important to monitor and manage urbanization and industrialization. In this letter, we propose two BU area extraction techniques based on the analysis of fully polarimetric synthetic aperture radar (PolSAR) data. Both methods exploit the geodesic distance on the unit sphere in the space of Kennaugh matrices. The first method is based on the three dominant scattering types in the scene and compares them with scattering models; if any of them matches with BU type elementary scattering models, then the pixel is said to belong to a BU area. The second method is based on a novel PolSAR BU index (RBUI) composed by considering scattering mechanisms from BU structures. The two proposed techniques are validated on two different urban scenes, one acquired at C-band by RADARSAT-2 and other at L-band by ALOS-2 SAR sensors.

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