항공기 표적의 HRRP-JEM 영상에서 복소 신호의 이심률을 이용한 제트 엔진 위치 추정

박지훈(Ji-Hoon Park),양우용(Woo-Yong Yang),배준우(Jun-Woo Bae),강성철(Seong-Cheol Kang),명로훈(Noh-Hoon Myung) 한국전자파학회 2013 한국전자파학회논문지 Vol.24 No.12

2005년에 처음 소개된 HRRP-JEM(High Resolution Range Profile-Jet Engine Modulation) 영상은 항공기 표적에 탑재된 제트 엔진의 장착 위치를 추정함으로써 레이더 표적 인식을 수행한다. 본 논문에서는 복소 신호의 이심률을 기반으로 HRRP-JEM 영상에서 제트 엔진 위치를 추정하기 위한 새로운 접근법을 제시한다. 복소 신호의 이심률은 HRRP-JEM 영상을 구성하는 어떤 거리 성분(range bin)에서의 레이더 수신 신호에 미치는 JEM 성분의 기여도를 효과적으로 산출할 수 있다. 따라서 JEM 성분의 기여도가 가장 큰 거리 성분이 제트 엔진의 위치에 해당하며, 이를 짚어냄으로써 보다 정량적이고 신뢰성 있는 제트 엔진 위치 추정이 가능할 것으로 기대된다. 사실적인 항공기 모델의 시뮬레이션 결과를 통해 본 논문에서 제안한 개념의 유효성을 입증하였다. High Resolution Range Profile-Jet Engine Modulation imagery first introduced in 2005 carries out radar target recognition by localizing the position of the jet engine installed on the aircraft target. This paper presents a new approach for estimating the jet engine position in the HRRP-JEM image based on the eccentricity of a complex signal. It can effectively evaluate the contribution of the JEM component to the radar received signal in a range bin of the HRRP-JEM image. Therefore, the localization is expected to be performed more quantitatively and reliably by pinpointing the range bin corresponding to the jet engine position where the JEM contribution is maximized. The simulation results of realistic aircraft models validated the effectiveness of the proposed concept.

T-103 항공기에 대한 JEM 스펙트럼 추출

김윤석(Yoon-Suk Kim),정주호(Joo-Ho Jung),김후(Hoo Kim) 대한전자공학회 2008 電子工學會論文誌-TC (Telecommunications) Vol.45 No.10

본고 및 연구를 통하여 JEM(Jet Engine Modulation)의 특성 및 기본원리를 파악하며, 실제 항공기 중 저속항공기의 RCS 및 JEM을 측정하는 것이 목적이다. 측정시에는 원하지 않는 여러 오차들이 발생하게 되는데 여러 오차를 제거하기 위해 교정(Calibration)방법을 사용하게 되는데 본고에서는 IACT(Isolated Antenna Calibration Technique)방법을 사용하였다. 측정은 옥외(Outdoor)에서 이루어졌으며 항공기는 공군에서 운용하고 있는 T-103을 표적으로 측정하였다. T-103에 대한 JEM스펙트럼을 추출하며 고정된 표적에 대한 주파수 특성과 도플러에 의한 변화를 판단하는 것이다. 주파수는 일반적인 공대공 항공기에서 운용되는 X밴드를 사용하여 측정하였으며 공대공 항공기에서 저속항공기를 식별하는데 있어 측정을 통하여 분석하였다. Characteristics of JEM(Jet Engine Modulation) are measured and principal meanings are grasped in this paper. This study's object is to measure RCS and JEM for actual aircraft, especially low speed craft. In experiment, various error are generated from unknown cause and for removal these, calibration technique known as IACT(Isolated Antenna Calibration Technique) is used. Experiment is executed at outdoor and target is T-103 which play in beginner course for ROKAF pilot. JEM spectrum of T-103 and frequency characteristics, doppler effects are extracted. X-band used in military aircraft for air-to-air fighting are selected. The data obtained through this study are analyzed to discriminate target especially low speed aircraft for current using radar(X-band)'s performance.

차세대 비디오 부호화 실험모델(JEM)의 화면내 예측 모드 부호화 기법

박도현,이진호,강정원,김재곤 한국방송∙미디어공학회 2018 방송공학회논문지 Vol.23 No.4

HEVC(High Efficiency Video Coding) 보다 뛰어난 압축 성능을 갖는 차세대 비디오 부호화 표준 후보 기술에 대한 탐색과 검증을 진행한 JVET(Joint Video Exploration Team)은 기술 검증을 위한 참조 SW 코덱인 JEM(Joint Exploration Model)을 공개하였다. JEM은 HEVC의 35개 보다 증가한 67개의 화면내 예측 모드를 사용하고 있으며, 이에 따른 예측 모드 부호화에 대한 부담으로 부호화 성능 개선에 제한이 따른다. 본 논문에서는 화면내 예측 모드의 선택 확률을 분석하고, 이를 바탕으로 보다 효율적인 화면내 예측 모드 부호화 기법과 그 기법의 효율적인 엔트로피 부호화를 위한 문맥 모델링 기법을 제안한다. 실험결과 제안 기법은 AI(All Intra) 부호화 구조에서 JEM 7.0 대비 0.02%의 BD-rate 이득을 보였으며, 향후 추가적인 성능 향상을 위한 문맥 모델링 최적화에 대한 연구가 필요하다.

Cosmic ray oriented performance studies for the JEM-EUSO first level trigger

Abdellaoui, G.,Abe, S.,Acheli, A.,Adams Jr., J.H.,Ahmad Jr., S.,Ahriche Jr., A.,Albert Jr., J.-N.,Allard Jr., D.,Alonso Jr., G.,Anchordoqui Jr., L.,Andreev Jr., V.,Anzalone Jr., A.,Aouimeur Jr., W.,Ar Elsevier BV * North-Holland 2017 Nuclear Instruments & Methods in Physics Research. Vol. No.

<P><B>Abstract</B></P> <P>JEM-EUSO is a space mission designed to investigate Ultra-High Energy Cosmic Rays and Neutrinos ( E > 5 ⋅ 1 <SUP> 0 19 </SUP> eV ) from the International Space Station (ISS). Looking down from above its wide angle telescope is able to observe their air showers and collect such data from a very wide area. Highly specific trigger algorithms are needed to drastically reduce the data load in the presence of both atmospheric and human activity related background light, yet retain the rare cosmic ray events recorded in the telescope. We report the performance in offline testing of the first level trigger algorithm on data from JEM-EUSO prototypes and laboratory measurements observing different light sources: data taken during a high altitude balloon flight over Canada, laser pulses observed from the ground traversing the real atmosphere, and model landscapes reproducing realistic aspect ratios and light conditions as would be seen from the ISS itself. The first level trigger logic successfully kept the trigger rate within the permissible bounds when challenged with artificially produced as well as naturally encountered night sky background fluctuations and while retaining events with general air-shower characteristics.</P>

An evaluation of the exposure in nadir observation of the JEM-EUSO mission

Adams, J.H.,Ahmad, S.,Albert, J.N.,Allard, D.,Ambrosio, M.,Anchordoqui, L.,Anzalone, A.,Arai, Y.,Aramo, C.,Asano, K.,Ave, M.,Barrillon, P.,Batsch, T.,Bayer, J.,Belenguer, T.,Bellotti, R.,Berlind, A.A. North-Holland ; Elsevier Science Ltd 2013 Astroparticle physics Vol.44 No.-

We evaluate the exposure during nadir observations with JEM-EUSO, the Extreme Universe Space Observatory, on-board the Japanese Experiment Module of the International Space Station. Designed as a mission to explore the extreme energy Universe from space, JEM-EUSO will monitor the Earth's nighttime atmosphere to record the ultraviolet light from tracks generated by extensive air showers initiated by ultra-high energy cosmic rays. In the present work, we discuss the particularities of space-based observation and we compute the annual exposure in nadir observation. The results are based on studies of the expected trigger aperture and observational duty cycle, as well as, on the investigations of the effects of clouds and different types of background light. We show that the annual exposure is about one order of magnitude higher than those of the presently operating ground-based observatories.

Ultra-violet imaging of the night-time earth by EUSO-Balloon towards space-based ultra-high energy cosmic ray observations

Abdellaoui, G.,Abe, S.,Adams Jr., J.H.,Ahriche Jr., A.,Allard Jr., D.,Allen Jr., L.,Alonso Jr., G.,Anchordoqui Jr., L.,Anzalone Jr., A.,Arai Jr., Y.,Asano Jr., K.,Attallah Jr., R.,Attoui Jr., H.,Ave P North-Holland 2019 Astroparticle physics Vol.111 No.-

<P><B>Abstract</B></P> <P>The JEM-EUSO (Joint Experiment Missions for the Extreme Universe Space Observatory) program aims at developing Ultra-Violet (UV) fluorescence telescopes for efficient detections of Extensive Air Showers (EASs) induced by Ultra-High Energy Cosmic Rays (UHECRs) from satellite orbit. In order to demonstrate key technologies for JEM-EUSO, we constructed the EUSO-Balloon instrument that consists of a ∼1 m<SUP>2</SUP> refractive telescope with two Fresnel lenses and an array of multi-anode photo-multiplier tubes at the focus. Distinguishing it from the former balloon-borne experiments, EUSO-Balloon has the capabilities of single photon counting with a gate time of 2.3 µs and of imaging with a total of 2304 pixels. As a pathfinder mission, the instrument was launched for an 8 h stratospheric flight on a moonless night in August 2014 over Timmins, Canada. In this work, we analyze the count rates over ∼2.5 h intervals. The measurements are of diffuse light, e.g. of airglow emission, back-scattered from the Earth’s atmosphere as well as artificial light sources. Count rates from such diffuse light are a background for EAS detections in future missions and relevant factor for the analysis of EAS events. We also obtain the geographical distribution of the count rates over a ∼780 km<SUP>2</SUP> area along the balloon trajectory. In developed areas, light sources such as the airport, mines, and factories are clearly identified. This demonstrates the correct location of signals that will be required for the EAS analysis in future missions. Although a precise determination of count rates is relevant for the existing instruments, the absolute intensity of diffuse light is deduced for the limited conditions by assuming spectra models and considering simulations of the instrument response. Based on the study of diffuse light by EUSO-Balloon, we also discuss the implications for coming pathfinders and future space-based UHECR observation missions.</P>

Overview of Potential Technologies for Future Video Coding Standard (FVC) in JEM Software

Ismail Marzuki,Donggyu Sim 대한전자공학회 2018 IEIE Transactions on Smart Processing & Computing Vol.7 No.1

In this paper, we present an investigation into several potential technologies that are being developed and prepared for Future Video Coding (FVC) standard. There are some requirements that need to be considered in delivering the FVC standard. The Joint Video Exploration Team (JVET) is now inspecting potential tools to be adopted as video coding technology under the Joint Exploration Model (JEM) reference software. This paper provides an overview of the technical features of JEM software, a brief account of the background, and the key elements according to the latest version of JEM software and its algorithm description.

약한 제트 엔진 변조 신호의 Spool Rate 추출을 위한 High-Pass Filtering 기반의 빠른 전처리 기법

송원영,김형주,김성태,신인선,명로훈 한국전자파학회 2019 한국전자파학회논문지 Vol.30 No.5

Jet engine modulation(JEM) signals are widely used for target recognition. These signals coming from a potentially hostile aircraft provide specific information about the jet engine. In order to obtain the number of blades, which is uniquely provided by the JEM signal, one must extract the spool rate, which is the rotation speed of the blades. In this paper, we propose an algorithm to extract the spool rate from a weak JEM signal. A criterion is developed to extract the spool rate from the JEM signal by analyzing the intensity of the JEM signal component. The weak signal is first subjected to a high-pass filtering-based process, which modifies it to facilitate spool rate extraction. We then apply a peak detection process and extract the spool rate. The technique is simpler than the existing CEMD or WD method, is accurate, and greatly reduces the time required

제트 엔진 변조신호에서 주파수 마스킹을 이용한 표적의 특징 추출 및 식별

김시호(Si-Ho Kim),김찬홍(Chan-Hong Kim),채대영(Dae-Young Chae) 한국전자파학회 2014 한국전자파학회논문지 Vol.25 No.4

본 논문은 항공기의 JEM(Jet Engine Modulation) 신호를 분석하여 표적을 식별하는 방법에 관한 것이다. 제트 엔진의 각 단의 날개 수 정보로부터 계산된 하모닉 주파수 마스크를 이용하여 스펙트럼을 분석함으로써 엔진 기종을 식별하는 방법을 제안한다. 기존의 방법처럼 각 단의 쵸핑(chopping) 주파수를 찾기 위한 복잡한 논리적 알고리즘이나 스펙트럼 비교 방법처럼 미리 모사된 엔진 스펙트럼 DB(Database)를 필요로 하지 않으며, 엔진 DB의 날개 수 정보를 이용하여 추출한 하모닉 성분을 비교함으로써 식별이 가능하다는 장점을 가진다. 또한, 정밀 축회전속도(spool rate)를 찾는 방법을 제시함으로써 날개 수 추정이나 하모닉 주파수의 위치 계산에서 오류를 줄일 수가 있다. This paper deals with the method to classify the aircraft target by analyzing its JEM signal. We propose the method to classify the engine model by analyzing JEM spectrum using the harmonic frequency mask generated from the blade information of jet engine. The proposed method does not need the complicated logic algorithm to find the chopping frequency in each rotor stage and the pre-simulated engine spectrum DB used in the previous methods. In addition, we propose the method to estimate the precise spool rate and it reduces the error in estimating the number of blades or in calculating the harmonic frequency of frequency mask.

구분기 신뢰도에 기반한 HRRP 및 JEM 융합 항공기 식별

김시호(Si-Ho Kim),이상인(Sang-In Lee),채대영(Dae-Young Chae) 한국전자파학회 2017 한국전자파학회논문지 Vol.28 No.3

본 논문에서는 항공기 식별을 위해 서로 보완적인 특성을 갖는 HRRP 구분기와 JEM 구분기를 융합하여 식별하는 방법을 제안한다. 다양한 상황에서 단일 구분기보다 향상된 식별성능을 얻기 위하여 식별결과에 대한 구분기의 신뢰도를 가중치로 융합하는 방법을 제안한다. 신뢰도는 구분기의 식별성능으로부터 추정된 사후확률로 정의되며 식별결과에 대한 확신도 및 관측각도에 따라 변하는 특성을 가진다. 시뮬레이션 데이터를 사용한 식별실험을 통해 제안한 융합 방법이 단일 구분기를 효과적으로 융합하여 향상된 식별성능을 얻을 수 있음을 확인하였다. In this paper, we propose a fusion classification method combining HRRP and JEM classifier with complementary properties for the classification of aircraft. The fusion method is based on the confidence of a classifier for a classification result to improve performance compared with single classifier in various situations. The confidence is defined as the posterior probability estimated from the classification performance of a classifier and it depends on the aspect angle and the certainty for a classification result. Through the classification test using simulation data, we can verify that the proposed fusion method shows good performance by fusing the classifiers effectively.