Tae-Hyung Kim

항공기 레이더는 하방 또는 사방의 공대공 표적을 탐지/추적하기 위하여 보통 MPRF 파형을 사용한다. 항공기용 레이더가 MPRF 파형을 운용하기 위하여, 거리/속도에서 존재하는 모호성을 해결하면서 클러터를 회피하여 하방 공대공 표적을 탐지할 수 있는 최적의 PRF들을 선택하여 운용할 수 있어야 한다. 이 논문은 실시간 환경변화 상황에서 표적을 탐지/추적하기 위한 최적의 PRF들을 실시간으로 찾는 방법을 제시한다. Airborne radar usually use MPRF(medium PRF) waveforms to detect and track look-down or all-directions air-to-air targets. To use MPRF waveforms, airborne radar have to operate optimal PRF schedules and select optimal PRFs able to detect look-down air-to-air targets,

Some airborne radars are equipped with a mode to quickly detect and track targets that approach the front of an aircraft at a high speed from a far distance. This paper explains the use of high pulse repetition frequency(HPRF) waveforms for operating this forward high-speed-target detection mode. HPRF waveforms are not ambiguous in reference to the target velocity, but they are so in the case of the target range. Therefore, the use of HPRF waveforms requires the resolving of the range ambiguity

Accurately measuring elevation angles of sea-skimming targets via monopulse processing is difficult owing to the multipath signals of sea surfaces. For tracking and shooting down sea-skimming anti-ship missiles, this study presents a fine measurement method for elevation angles of targets under constrained conditions in terms of antenna beam widths of the close-in weapon system (CIWS) radar. This method is based on Eckersten’s implementation of the “complex angle”. We design a specific applicati

Medium pulse repetition frequency (MPRF) waveforms are used in common airborne radar because of their advantages. However, one of the disadvantages of MPRF waveforms is the decrement of detectable ranges by sidelobe clutter at low-altitude platforms. To overcome this disadvantage and to increase the detectable ranges at low-altitude platforms, this study proposes a sidelobe clutter reduction method. Airborne radar has sum and difference antenna channels, and sidelobe clutter reduction is process

항공기용 펄스 도플러 위상 배열 레이더에 관한 시간 영역에서의 클러터 생성 모델을 제시한다. 구형의 지구라는 가정에서 클러터 패치의 기하학적 위치를 고려하여 시간 영역의 지표면 클러터 신호를 생성하였으며, 부배열 단위로 클러터 신호를 생성하였다. 이렇게 생성한 부배열 단위의 클러터 신호는 DBF(Digital Beamforming), ABF(Adaptive Beamforming), STAP(Space-Time Adaptive Processing) 등의 다양한 레이더 응용에서 시뮬레이션 입력 신호로 사용되어질 수 있다. Time-domain clutter generation model for airborne pulse doppler phase-array radar is presented. Time-domain surface clutter signal is generated assuming earth of a sphere and considering geometry of a clutte

Applications of Sigma-Delta STAP, and a method of GMTI processing are presented for GMTI(Ground Moving Target Indication) mode of airborne radar with sigma, delta, and guard channels. We showed results of performance analyses of presented methods by clutter simulation with ICM(Internal Clutter Motion), signal processing simulation and MDV(Minimum Detectable Velocity). Presented methods for Sigma-Delta STAP and GMTI processing are easy to apply practically in GMTI mode of airborne radar without r

Tracking and detecting targets by the M/W seeker is affected by the clutter reflecting from the earth's surface. In order to detect the look-down retreating targets, which appear in the sidelobe clutter region, in the M/W seeker of High PRF mode, it is necessary to understand statistical characteristics of the surface sidelobe clutter. Statistical analysis of sidelobe clutter is conducted for several configurations of the surface using data obtained by the CFT (Captive Flight Test) of the M/W se

An optimal optical configuration for producing symmetric left- and right-circularly-polarized light for a three-dimensional (3D) circularly-polarized active retarder (CP-AR) display is proposed. It consists of a λ/2 retardation switching liquid crystal (LC) cell and two positive A-plate films. When the vertical electric field that is applied to the λ/2 retardation-switching LC cell is alternately turned on and off, the overall AR panel produces left- and right-circularly-polarized light for the

제한적이고 유한한 합리성을 인식하고 인간의 행동과 동기를 연구하는 행동경제학은 다양한 분야에서 관심을 받고 있으나, 환경정책 분야에서는 이에 상응하는 연구가 부족한 실정이다. 따라서 본 연구는 다양한 심리학적 개념을 사용하여 환경정책과 관련된 합리적 의사결정 및 이행을 위한 행동경제학적 개념의적용가능성을 탐색하였으며, 그 영향력을 평가할 때 인구사회학적 변수 및 내적 특성을 통제하여 보다 타당성을 높이고자 하였다. 대학원생을 대상으로 실시한 본 연구의 실험에서는 매몰비용 편의, 민감성 체감등 행동경제학 개념이 유의하게 나타났으며, 혼잡통행료 및 탄소배출권 지불용의액과 수용가능성에 관한다중회귀분석은 사전에 제공한 기준점인 앵커링이 조절된 예측치에 강한 영향을 미친다는 점을 밝혔다. 이로부터 행동경제학 개념이 가지는 환경정책적 함의를 도출하였다.

Some airborne radars provide the raid assessment mode, which enables the operator to separate closely spaced airborne targets, allowing the operator confirm the number of planes in a dense squadron. This paper presents a design of waveform operation, target extraction, and signal processing method for implementation of the raid assessment mode based on an AESA (active electronically scanned array) radar. The function and performance using our proposed method were confirmed through simulations an