• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.4
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• pp.431-439
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• 2010

Cross-interferometic synthetic aperture radar (CInSAR) technique from ERS-2 and Envisat images is capable of generating submeter-accuracy digital elevation model (DEM). However, it is very difficult to produce high-quality CInSAR-derived DEM due to the difference in the azimuth and range pixel size between ERS-2 and Envisat images as well as the small height ambiguity of CInSAR interferogram. In this study, we have proposed an efficient method to overcome the problems, produced a high-quality DEM over northern Alaska, and compared the CInSAR-derived DEM with the national elevation dataset (NED) DEM from U.S. Geological Survey. In the proposed method, azimuth common band filtering is applied in the radar raw data processing to mitigate the mis-registation due to the difference in the azimuth and range pixel size, and differential SAR interferogram (DInSAR) is used for reducing the unwrapping error occurred by the high fringe rate of CInSAR interferogram. Using the CInSAR DEM, we have identified and corrected man-made artifacts in the NED DEM. The wave number analysis further confirms that the CInSAR DEM has valid Signal in the high frequency of more than 0.08 radians/m (about 40m) while the NED DEM does not. Our results indicate that the CInSAR DEM is superior to the NED DEM in terms of both height precision and ground resolution.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.421-430
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• 2003

In this paper, we propose a method to consider SAR(Specific Absorption Rate) at beginning stage of handsets development. First, simulation was carried out with changing folding angle from 150$^{\circ}$to 142$^{\circ}$. Simulation results show that SAR value is decreased with decreasing the folding angle. When folding angle is 142$^{\circ}$, error between simulation and measurement results is about 3.95 %. Second, we made some experiments with EMI (Electromagnetic Interference) paint, and its results show that different pattern of EMI paint have different SAR values. After removing EMI paint at the lower part of antenna feeding point, we got the decrease efficiency of 15.46 % for SAR value. When we applied zigzag painting pattern, we got the highest SAR decrease efficiency.

• Korean Journal of Microbiology
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• v.38 no.3
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• pp.162-167
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• 2002

To analyse proteins and gene related to antifungal activity, SAR01 strain was isolated from a brown seaweed and identified as Streptomyces sp. by FAME(fatty acid methyl ester) analysis. Antifungal activity deficient mutant(SAR535) of Streptomyces sp. SAR01 was induced by gamma radiation$({60}^Co)$. It was found that 6 specific protein spots appeared only in SAR01 by 2-D electrophoresis analysis. Among them, a protein of 10 kDa had homology of 96% with 10 kD chaperonin cpn 10 (GroES) by Basic Local Alignment Search Tool(BLAST, NCBI) analysis. SAR535 transformants into which groES was transferred by electroporation revealed antifungal activity newly similar with SAR01 It suggested that groES be supposed to be related to the antifungal activity of Streptomyces sp. SAR01.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.257-272
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• 2007

This paper analyzed relationships between various features from SAR data with multiple acquisition dates and mode (frequency, polarization and incidence angles), and land-cover classes. Two typical types of features were extracted by considering acquisition conditions of currently available SAR data. First, coherence, temporal variability and principal component transform-based features were extracted from multi-temporal and single mode SAR data. C-band ERS-1/2, ENVISAT ASAR and Radarsat-1, and L-band JERS-1 SAR data were used for those features and different characteristics of different SAR sensor data were discussed in terms of land-cover discrimination capability. Overall, tandem coherence showed the best discrimination capability among various features. Long-term coherence from C-band SAR data provided a useful information on the discrimination of urban areas from other classes. Paddy fields showed the highest temporal variability values in all SAR sensor data. Features from principal component transform contained particular information relevant to specific land-cover class. As features for multiple mode SAR data acquired at similar dates, polarization ratio and multi-channel variability were also considered. VH/VV polarization ratio was a useful feature for the discrimination of forest and dry fields in which the distributions of coherence and temporal variability were significantly overlapped. It would be expected that the case study results could be useful information on improvement of classification accuracy in land-cover classification with SAR data, provided that the main findings of this paper would be confirmed by extensive case studies based on multi-temporal SAR data with various modes and ground-based SAR experiments.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.1
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• pp.105-113
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• 2010

SAR(Synthetic Aperture Radar) has characteristics well-suited for the measurement of geophysical parameters during day and night in all weather conditions. Recently, SAR data with high resolution acquired by satellites became available to the public. In such data, many features and phenomena of geometric structure of man-made objects and natural environments become observable. In this paper, we discuss main considerations including geometric distortion and coregistration for efficient utilization of high resolution SAR images. And, various advanced technologies in SAR application fields are introduced.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.7-16
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• 2011

This study discussed the applicability of satellite SAR (Synthetic Aperture Radar) imagery with regard to reservoir monitoring, and tried the extraction of reservoir storage from multi-temporal C-band RADARSAT-1 SAR backscattering images of Yedang and Goongpyeong agricultural reservoirs, acquired from May to October 2005. SAR technology has been advanced as a complementary and alternative approach to optical remote sensing and in-situ measurement. Water bodies in SAR imagery represent low brightness induced by low backscattering, and reservoir storage can be derived from the backscatter contrast with the level-area-volume relationship of each reservoir. The threshold segmentation over the routine preprocessing of SAR images such as speckle reduction and low-pass filtering concluded a significant correlation between the SAR-derived reservoir storage and the observation record in spite of the considerable disagreement. The result showed up critical limitations for adopting SAR data to reservoir monitoring as follows: the inappropriate specifications of SAR data, the unreliable rating curve of reservoir, the lack of climatic information such as wind and precipitation, the interruption of inside and neighboring land cover, and so on. Furthermore, better accuracy of SAR-based reservoir monitoring could be expected through different alternatives such as multi-sensor image fusion, water level measurement with altimeters or interferometry, etc.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.2
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• pp.118-127
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• 2018

In this work, we have designed and manufactured radar target simulation equipment for the performance analysis of synthetic aperture radar(SAR) systems. First, we have explained the function and performance specification of the target simulation equipment and point target scenario generation for validation of the SAR system. In addition, we have developed a simple and accurate calibration method for the time delay of the SAR system using the manufactured target simulation equipment. We have analyzed the point target impulse response function of the SAR image acquired using the SAR system and the target simulation equipment. It was observed that the measured peak to side lobe ratio(=-13.25 dB) and resolution(=0.49 m) are in good agreement with the corresponding theoretical values.

• Korean Journal of Remote Sensing
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• v.27 no.5
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• pp.555-563
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• 2011

Nowadays, demands with respect to applications based on geo-based information on mobile device such as smartphone and those based on open platform or open source have been increasing. This trend can be regarded as significant opportunities to widen application fields and to expand industry business cases using satellite imagery. However, it needs a different approach from conventional remote sensing researches. This work focuses on SAR among many kinds of geo-based data resources. First, an application for Interferometric SAR processing based on open source was implemented. And using this, InSAR data was processed and stored into database. When smartphone users at any places request InSAR results, they can receive InSAR information and concerned metadata on their device. An smartphone application for this task was designed and implemented in this study. This provides a practical way for SAR service for smartphone, and can apply to build mobile service system of complex and compound types of remote sensing resources and their derived contents.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.475-491
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• 2021

With the recent increase in available high-resolution (< ~1 m) satellite SAR images, the demand for precise registration of SAR images is increasing in various fields including change detection. The registration between high-resolution SAR images acquired in different look angle is difficult due to speckle noise and geometric distortion caused by the characteristics of SAR images. In this study, registration is performed in two stages, coarse and fine, using the x-band SAR data imaged at staring spotlight mode of TerraSAR-X. For the coarse registration, a method combining the adaptive sampling method and SAR-SIFT (Scale Invariant Feature Transform) is applied, and three rigid methods (NCC: Normalized Cross Correlation, Phase Congruency-NCC, MI: Mutual Information) and one non-rigid (Gefolki: Geoscience extended Flow Optical Flow Lucas-Kanade Iterative), for the fine registration stage, was performed for performance comparison. The results were compared by using RMSE (Root Mean Square Error) and FSIM (Feature Similarity) index, and all rigid models showed poor results in all image combinations. It is confirmed that the rigid models have a large registration error in the rugged terrain area. As a result of applying the Gefolki algorithm, it was confirmed that the RMSE of Gefolki showed the best result as a 1~3 pixels, and the FSIM index also obtained a higher value than 0.02~0.03 compared to other rigid methods. It was confirmed that the mis-registration due to terrain effect could be sufficiently reduced by the Gefolki algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11A
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• pp.1858-1863
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• 2001

SAR data consist of magnitude and phase, and IFSAR technique using phase data is very useful high technology Producing fee height information. To use IFSAR technique effectively in the operation of SAR, this paper suggests the essential requirement and main consideration during SAR design process. Also the critical baseline, one of the principal elements, is derived, and it proposes applicable method through the simulation and discussion to the E-SAR.