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Yanggu, South Korea

Ha J.S.,Agency for Defense Development | Park G.C.,Agency for Defense Development | Lee J.S.,Agency for Defense Development | Cho B.L.,Agency for Defense Development | And 3 more authors.
2011 3rd International Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2011 | Year: 2011

A forward imaging radar (FIR) detecting obstacles from the ground needs 2-D imaging methods for an unmanned ground vehicle (UGV). Although a back-projection method is the most suitable algorithm, its processing time is too slow to make 2D image in real time. To make a fast imaging algorithm such as frequency domain algorithm, the proposed algorithm uses the scaling factor of that algorithm. This paper proposes a fast data processing algorithm using the scaling factor, based on mono-static SAR system. © 2011 KIEES. Source


Shin D.,Satrec Initiative Co. | Lee S.,Satrec Initiative Co.
International Journal of Remote Sensing | Year: 2015

This article describes a technique which estimates line-of-sight (LOS) parameters of each CCD array in a high-resolution electro-optical sensor on board a satellite using statistical information which is extracted automatically from a large number of real images acquired after launch. First, the focal length of panchromatic (PAN) CCD arrays is estimated by using thousands of ground control points (GCPs) converted to raw image space. Second, a model is introduced for deriving LOS parameters for multispectral (MS) CCD arrays in one focal plane assembly (FPA) such as the focal lengths and the first/last detector cell positions from automatically matched band-to-band (B2B) tie-points. Finally, the LOS parameters of all arrays in one FPA are updated using automatically matched tie-points in the overlap zone (OZ) in order to represent the geometrical relationship between the CCD arrays with the same spectral band in two FPAs. The proposed technique was applied to the calibration of a ground segment image processor for a currently operating high-resolution imaging satellite during its initial commissioning phase. This article describes the accuracy and robustness of the LOS parameters estimated by the proposed technique by using more than one hundred images covering full geographical locations and off-nadir tilt angle ranges. © 2015, © 2015 Taylor & Francis. Source


Kim D.-H.,Satrec Initiative Co. | Yoon J.-C.,Korea Aerospace Research Institute | Shin J.-M.,Korea Aerospace Research Institute | Kim M.-G.,Satrec Initiative Co.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2010

In KOMPSAT-5 program, Korea Aerospace Research Institute has made SAR imaging chain analysis tool to evaluate imaging system of KOMPSAT-5. The tool consists of a simulator and a processor. The simulator simulates observation of a scene by the operational mode of KOMPSAT-5 and generates SAR raw data. The processor generates an image of the scene. This paper is about the second part of processing the simulated raw data that is acquired by the step steering sliding spotlight mode of KOMPSAT-5. For this observation mode, dechirp on receive is operated in receiving the echoes. So, extended frequency scaling algorithm is used to process the raw data in order to directly handle the dechirped data [2]. This paper mainly contributes for the accuracy of effective velocity. The effective velocity criterions for range and azimuth processing allows that the processor uses only one scene center effective velocity in range processing and several ones in azimuth processing. In this paper, a method to increase the accuracy of calculation of effective velocity is also proposed. Simulation result shows that the proposed method is valid. © 2010 IEEE. Source


Yoon H.,Satrec Initiative Co. | Paek S.W.,Massachusetts Institute of Technology | Lim Y.,Korea Advanced Institute of Science and Technology | Lee B.-H.,Satrec Initiative Co. | Lee H.,Satrec Initiative Co.
IEEE Transactions on Aerospace and Electronic Systems | Year: 2013

We propose a new star pattern identification algorithm using the vector pattern matching technique on the celestial sphere. The proposed algorithm provides more robust identification performance in cases where the captured star images are biased from the onboard catalog star image positions. The technique is based on the approach of maximizing the target score function, which is formed by the correlation between the original and the reference star patterns on the celestial sphere. © 1965-2011 IEEE. Source


Kim D.H.,Satrec Initiative Co. | Kim T.H.,Satrec Initiative Co. | Choi W.H.,Satrec Initiative Co. | Seon S.G.,Agency for Defense Development | And 2 more authors.
2011 3rd International Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2011 | Year: 2011

The system that this paper deals about is one stationary bistatic SAR using ultra wide band chirp pulse. Because of the large bandwidth, the echo signal is mixed with the transmitted signal. Then the mixed signal is saved as a raw data. The system has an intrinsic difficulty in processing the raw data due to the long pulse bandwidth. So, it is very complicated to process the data in Doppler domain. This paper proposes an alternative way of processing the data acquired by this kind of SAR system. © 2011 KIEES. Source

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