Si-Ho Kim

Bio: Si-Ho Kim is an academic researcher from Agency for Defense Development. The author has contributed to research in topics: Inverse synthetic aperture radar & Radar. The author has an hindex of 5, co-authored 13 publications receiving 71 citations.

Efficient classification of ISAR images using 2d fourier transform and polar mapping

Abstract: This paper proposes an efficient method to classify inverse synthetic aperture radar (ISAR) images. The proposed method achieves invariance to translation and rotation of ISAR images by using two-dimensional (2D) Fourier transform (FT) of ISAR images, polar mapping of the 2D FT image, and a simple nearest-neighbor classifier. In simulations using ISAR images measured in a compact range, the proposed method yielded high classification ratios with small-sized data regardless of the location of the rotation center, whereas the existing method was very sensitive to the location of it.

Micro-Doppler Extraction and Analysis of the Ballistic Missile Using RDA Based on the Real Flight Scenario

Abstract: Micro-Doppler (MD) caused by the motion of the ballistic missile can contribute to successful recognition of the ballistic missile. Considering the real observation scenario. This paper proposes a method to derive the MD image of the ballistic missile by applying the range-Doppler algorithm (RDA) based on the real ∞ight scenario and analyzes the factor for the real-time MD imaging. Simulation results using the ∞ight trajectory constructed using the real target parameter demonstrate that we need a new cost function for phase adjustment and a new method for range alignment. In addition, matched-flltering needs to be performed in the baseband, and a su-cient PRF is required to prevent discontinuity of the MD image. Dechirping of MD and flltering of the random movement are also needed for a clear MD image. Among the various weapons used in the modern battlefleld, the ballistic missile in∞icts the biggest threat due to its high maneuvering speed and low radar cross section (RCS), and thus defending against the ballistic missile is a major issue. Recently, a theory has been developed to explain micro-Doppler (MD) efiect caused by the micro motion of the target and applied for radar target recognition purpose (1,2). In the case of the ballistic missile, three motion components | spinning, conning and nutation | cause MD, and they can be utilized for target recognition in combination with the motion parameter (1,3,4). However, very little research has been reported on its application to the real ∞ight scenario and the factor that needs to be considered for the real-time MD imaging. In this paper, considering the real observation scenario by a radar, we propose a method to extract an MD signature of a ballistic missile engaged in the real ∞ight scenario by applying the range-Doppler algorithm (RDA), which is generally used to form the inverse synthetic aperture radar (ISAR) image (5{8), and analyze various factors for the real-time high quality MD image. For this purpose, we constructed the ∞ight trajectory by using the real motion parameters of a 500km range scud missile conducted a translation motion compensation (TMC). Then, the time-varying MD image was formed by applying the time-frequency transform (TFT). Various simulations were performed by using the obtained MD image to study the requirement for the real-time MD imaging. Simulation results obtained by using a target composed of the point scatter demonstrate that the MD signature can be successfully constructed by using the range-Doppler algorithm. However, a new method for TMC is required for real-time high-quality MD imaging. In addition, matched-flltering (MF) in the baseband is required to form a focused image, and a su-cient PRF is needed to remove discontinuity. The re∞ected signal needs to be dechirped to reduce the required PRF, and a fllter needs to be designed to remove the random movement.

Micro-doppler analysis of korean offshore wind turbine on the l-band radar

Abstract: To cope with the energy shortage and the rising cost of the fossil fuel, many wind farms are being constructed under the supervision of Korean government along the coasts of Korean peninsula to generate clean and renewable energy. However, construction of these wind farms may cause negative efiect on various L-band radars in operation. This paper presents the result of the micro-Doppler (MD) analysis of the in∞uence of the wind turbine on the L-band radar using the point scatterer model and the radar cross section of the real turbine predicted by the method of physical optics. The simulation results obtained at three observation angles show that the range of MD occupies a considerable portion of the helicopter MD range, and thus, the operations using helicopters need to be avoided in the wind farm region, and additional radars are required for the recognition of helicopter-like objects.

Estimation of the micro-motion parameters of a missile warhead using a micro-Doppler profile

Abstract: This paper deals with the problem of estimating micro-motion parameters. The proposed algorithm uses independent-component analysis to decompose the received signals into individual scatterer signals, and uses particle-swarm optimization to estimate the micro-motion parameters in a micro-Doppler profile. Simulation results show that the proposed method can successfully estimate micro-motion parameters of a warhead model consisting of many point scatterers.

Classification of Targets Improved by Fusion of the Range Profile and the Inverse Synthetic Aperture Radar Image

Abstract: The range proflle (RP) and the inverse synthetic aperture radar (ISAR) image are the useful radar signatures for classifying unknown targets because they can be used regardless of day- night and weather conditions. Since classiflcation that uses RP and ISAR is heavily dependent on ∞ight conditions, however, much more study is required on this topic. This paper proposes an e-cient method of classifying targets by using a classifler-level fusion of RP and ISAR as well as a scenario-based construction method of the training database. Simulation results using the flve targets composed of point scatterers prove that the proposed method yields high classiflcation results when the targets are ∞ying in a variety of directions at both short and long ranges.

Spotlight Synthetic Aperture Radar Signal Processing Algorithms

Abstract: Thank you very much for downloading spotlight synthetic aperture radar signal processing algorithms. Maybe you have knowledge that, people have search numerous times for their favorite books like this spotlight synthetic aperture radar signal processing algorithms, but end up in malicious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they juggled with some harmful virus inside their laptop.

'The Micro-Doppler Effect in Radar' by V.C. Chen

Abstract: This is a book review of 'The Micro-Doppler Effect in Radar' by V. C. Chen. Artech House, 16 Sussex Street, London, SW1V 4RW, UK. 2011. 290pp + diskette. Illustrated. £90. ISBN 978-1-60807-057-2.

Introduction to Radar Systems.Merrill I. Skolnik. McGraw-Hill Book Co., London and New York. 1962. 648 pp. Illustrated. £5 12s. 6d.

Abstract: Creep in Structures. Nicholas J. Hoff (Editor). Colloquium held at Stanford University, California, \\lth-\\5th July 1960. Springer Verlag, Berlin. 1962. 375 pp. DM 54. The first experiment on creep buckling was probably that made by Eaton Hodgkinson about 1890 when he recorded that a cast-iron pillow one inch in diameter and six feet long supported a load of 1,456 lb. for five or six months and then broke. Meanwhile, William Fairbairn, busy testing model tubes of wrought iron for the Britannia tubular bridge, was noting with satisfaction that, although the deflection of the tube under five times working load increased from ~i\\ to 3 j inches in 19 hours, under three times working load a similar increase took 20 days. Were these two gentlemen present in spirit at Stanford in July 1960, probably they would have found much to approve and perhaps even more to deplore. If the twenty papers are printed in the order in which they were delivered, Fairbairn anyway could barely have endured the first half. He would scarcely have recognised his old familiar wrought iron as a viscoelastic material, nor have seen in the disappearance of the shear centre the key to Robert Stephenson's apprehension of the dangers of twist. His appetite would have been whetted by the titles to the first eight papers with their several references to beams, plates and membranes, to combined stresses, varying load and temperature and incremental loading; but, listening, he would certainly have concluded that \"to go into such laborious and obstruse calculations was beyond his power\"; and he would have fled at half time \"to rest the basis of his calculation entirely on the experimental facts as deduced from tests on the proper models.\" Of course, the practical designer is always liable to run back to old fashioned methods; but it is simply no use improving mathematical techniques and complicated aids without at the same time developing the means to communicate the improvements to the practical designer. Had Fairbairn survived to the ninth paper he would have pricked up his ears. The term \"oil canning\" would have been strange to him and the references of course unknown; the notation is deplorable and the mathematics poorly set out; yet the description of the process is so lucid that these drawbacks scarcely hinder understanding of the way in which creep may contribute to snap action. Even better are later papers on the mechanics of column creep, and on the \"geometrically nonlinear creep buckling of bars\" (the worst feature of the latter paper is its title—it means very large deflections, as of an archer's bow; in fact the elastica, only not elastic). Several others of the last twelve papers are quite readable and they should encourage the reader to take another look at those he skipped first time. The editor brings up the rear with a study of damping in the vibration of a helical spring. It is a pity that the post of editor, qua se, seems to have become a sinecure; had this set of papers been really thoroughly edited—notation, layout, style and all else—its value would have been enormously enhanced.—H. L. COX.

Analysis of Moving Human Micro-Doppler Signature in Forest Environments

Abstract: Automatic detection of human motion is important for security and surveillance applications. Compared to other sensors, radar sensors present advantages for human motion detection and identiflcation because of their all-weather and day-and-night capabilities, as well as the fact that they detect targets at a long range. This is particularly advantageous in the case of remote and highly cluttered radar scenes. The objective of this paper is to investigate human motion in highly cluttered forest medium to observe the characteristics of the received Doppler signature from the scene. For this purpose we attempt to develop an accurate model accounting for the key contributions to the Doppler signature for the human motion in a forest environment. Analytical techniques are combined with full wave numerical methods such as Method of Moments (MoM) enhanced with Fast Multipole Method (FMM) to achieve a realistic representation of the signature from the scene. Mutual interactions between the forest and the human as well as the attenuation due to the vegetation are accounted for. Due to the large problem size, parallel programming techniques that utilize a Graphics Processing Unit (GPU) based cluster are used.

ISAR Imaging of Maneuvering Target Based on the Quadratic Frequency Modulated Signal Model With Time-Varying Amplitude

Abstract: Inverse synthetic aperture radar (ISAR) imaging of maneuvering target plays an important role in the field of national defense and surveillance. In this case, the conventional range Doppler algorithm is unsuitable to generate a well-focused ISAR image due to the time-varying property of the Doppler frequency during the integrated imaging interval. Furthermore, the dihedral or trihedral components of the imaging target or the phenomena of migration through resolution cell for the target's complex motion will induce the time-varying performance of the amplitude for the received signal. In this paper, the received signal in a range bin is depicted as multicomponent quadratic frequency-modulated signal with time-varying amplitude, and the generalized cubic phase function is used to estimate the parameters of it. Associated with the range instantaneous Doppler technique, the images quality can be enhanced distinctly compared with the conventional constant amplitude signal model. Results of simulated and read data demonstrate the effectiveness of the novel algorithm proposed in this paper.