scholarly journals A Novel Method for Refocusing Moving Ships in SAR Images via ISAR Technique

2021 ◽  
Vol 13 (14) ◽  
pp. 2738
Author(s):  
Xinlin Jia ◽  
Hongjun Song ◽  
Wenjing He
Keyword(s):  
Synthetic Aperture Radar ◽  
Phase Error ◽  
Three Dimensional ◽  
Simulated Data ◽  
Microwave Remote Sensing ◽  
Synthetic Aperture ◽  
Sar Images ◽  
Rectangular Window ◽  
Novel Method ◽  
Aperture Radar

As an active microwave remote sensing device, synthetic aperture radar (SAR) has been widely used in the field of marine surveillance. However, moving ships appear defocused in SAR images, which seriously affects the classification and identification of ships. Considering the three-dimensional (3-D) rotational motions (roll, pitch, and yaw) of the navigating ship, a novel method for refocusing moving ships in SAR images based on inverse synthetic aperture radar (ISAR) technique is proposed. First, a rectangular window is used to extract the defocused ship subimage. Next, the subimage is transformed into the ISAR equivalent echo domain, and the range migration and phase error caused by the identical movement of all ship scatterers are compensated. Then, the optimal imaging time can be selected by the maximum image contrast search method. Finally, the iterative adaptive approach (IAA) is used to obtain the image with high resolution. This method has satisfactory imaging performance in both azimuth resolution and image focus, and the amount of calculation is small due to the processing of subimages. Simulated data and Gaofen-3 real SAR data are used to verify the effectiveness of the proposed method.

scholarly journals Refocusing Moving Ship Targets in SAR Images Based on Fast Minimum Entropy Phase Compensation

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1154 ◽  
Author(s):  
Xiangli Huang ◽  
Kefeng Ji ◽  
Xiangguang Leng ◽  
Ganggang Dong ◽  
Xiangwei Xing
Keyword(s):  
Synthetic Aperture Radar ◽  
Phase Error ◽  
Synthetic Aperture ◽  
Sar Image ◽  
Minimum Entropy ◽  
Sar Images ◽  
Phase Compensation ◽  
Translation Motion ◽  
Airborne Sar ◽  
Aperture Radar

Moving ship targets appear blurred and defocused in synthetic aperture radar (SAR) images due to the translation motion during the coherent processing. Motion compensation is required for refocusing moving ship targets in SAR scenes. A novel refocusing method for moving ship is developed in this paper. The method is exploiting inverse synthetic aperture radar (ISAR) technique to refocus the ship target in SAR image. Generally, most cases of refocusing are for raw echo data, not for SAR image. Taking into account the advantages of processing in SAR image, the processing data are SAR image rather than raw echo data in this paper. The ISAR processing is based on fast minimum entropy phase compensation method, an iterative approach to obtain the phase error. The proposed method has been tested using Spaceborne TerraSAR-X, Gaofeng-3 images and airborne SAR images of maritime targets.

scholarly journals Earth Environmental Monitoring Using Multi-Temporal Synthetic Aperture Radar: A Critical Review of Selected Applications

2021 ◽  
Vol 13 (4) ◽  
pp. 604
Author(s):  
Donato Amitrano ◽  
Gerardo Di Martino ◽  
Raffaella Guida ◽  
Pasquale Iervolino ◽  
Antonio Iodice ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Synthetic Aperture Radar ◽  
Microwave Remote Sensing ◽  
Radar Data ◽  
Synthetic Aperture ◽  
Special Focus ◽  
Arid Environments ◽  
Synthetic Aperture Radar Data ◽  
Multi Temporal ◽  
Aperture Radar

Microwave remote sensing has widely demonstrated its potential in the continuous monitoring of our rapidly changing planet. This review provides an overview of state-of-the-art methodologies for multi-temporal synthetic aperture radar change detection and its applications to biosphere and hydrosphere monitoring, with special focus on topics like forestry, water resources management in semi-arid environments and floods. The analyzed literature is categorized on the base of the approach adopted and the data exploited and discussed in light of the downstream remote sensing market. The purpose is to highlight the main issues and limitations preventing the diffusion of synthetic aperture radar data in both industrial and multidisciplinary research contexts and the possible solutions for boosting their usage among end-users.

A test of airborne, side-looking synthetic-aperture radar in central Newfoundland for geological reconnaissance

1991 ◽  
Vol 28 (2) ◽  
pp. 257-265 ◽  
Author(s):  
D. F. Graham ◽  
D. R. Grant
Keyword(s):  
Surface Roughness ◽  
Synthetic Aperture Radar ◽  
Three Dimensional ◽  
Synthetic Aperture ◽  
Structural Elements ◽  
Terrain Classification ◽  
Regional Trends ◽  
Valuable Complement ◽  
Wide Swath ◽  
Aperture Radar

Side-looking, C-band synthetic-aperture radar (SAR) penetrates cloud and fog, and operates day or night, to produce pseudo-three-dimensional terrain images with enhanced topography and surface roughness. The images, which have a 20 m resolution and cover large areas, have been used to map the regional trends, patterns of lineaments, and terrain types over a 6200 km2 area of complex lithology, structure, and drift cover. Four lineament classes are differentiated. Glacial trends are clear, and bedrock structures (faults, fractures, joints, foliation, and folded bedding) with relief expression at the surface show through the drift as lineaments. They accurately reproduce most known features when compared with bedrock and Quatenary geology maps. Hitherto unrecognized structural elements are revealed. Tones and textures reflect minute surface roughness variations useful in terrain classification. SAR wide-swath-mode imagery is thus a valuable complement to aerial photography, and is superior in revealing hummocky moraine, ribbed moraine, boulder fields and stony till. Wider use of this imagery is encouraged.

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