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다중 레이더 배치를 위한 폐쇄형 표적추적 성능지표 산출
조형찬(Hyung-Chan Cho),정보영(Bo-Young Jung),서의석(Ui-Suk Suh),김영원(Young-Won Kim),나원상(Won-Sang Ra) 대한전기학회 2021 전기학회논문지 Vol.70 No.9
This paper suggests the closed-form target tracking performance measure which is necessary for formulating a multi-radar placement problem. It is well-known that there is no analytic solution to the DRE(differential Riccati equation) of a nonlinear target tracking filter, which makes the problem intractable. As a fundamental resolution to this technical issue, the line-of-sight frame equivalents of the given nonlinear filter are exploited. For such case, unlike the existing numerical method, the analytic solutions to the corresponding DREs can be readily derived. This idea was based on the fact that the Fisher information is preserved regardless of the coordinates system in which a tracking filter is designed. The proposed approach allows us to clearly describe the tracking performance measure as a function of the radars’ positions as well as their specification. Simulations confirm that our scheme is beneficial for reducing the inherent complexity of a multi-radar placement problem.
조형찬(Jong-Yun Jung),정종윤(Chun-Man Lee),이춘만(Hyung-Chan Cho),황영국(Young-Kug Hwang) 한국기계가공학회 2005 한국기계가공학회 춘추계학술대회 논문집 Vol.2005 No.-
친 환경적인 가공기술은 드라이 가공과 세미드라이 가공 등 절삭유를 사용하지 않거나 최소량을 사용하는 방법으로 환경오염을 줄이고 유해 환경을 개선하여 작업자를 보호하는 기술을 주요 테마로 한다. 건식가공은 절삭유를 사용하지 않고 주로 코팅공구가 사용되지만 가공 후 공작물의 표면 품위에 많은 문제가 발생한다. 이를 해결하기 위한 친환경적인 식물성 오일을 미스트로 만들어 아주 적은 극미량을 이용하는 MQL (Minimum Quantity of Lubrication) 절삭가공법에 대한 필요성이 제기된다.<br/> 본 연구에서는 절삭의 표면거칠기에 영향을 미치는 인자들을 선정하고 선정된 인자들의 수준을 정하여 실험한 후 표면품위와 절삭조건과의 상관관계를 규명하며, MQL 가공에서의 표면거칠기 향상에 최적화된 절삭조건을 구한다. 절삭 실험의 인자로는 MQL, 절삭속도, 이송속도, 절삭깊이며 수준의 수는 MQL 3수준 절삭속도 4수준 이송속도 3수준 절삭깊이 3수준으로 선정하여 실험을 한다.
함정 근접방어체계의 요격성능 향상을 위한 고기동 표적의 장시간 궤적 예측기법
함다혜(Dahye Ham),조형찬(Hyung-Chan Cho),나원상(Won-Sang Ra),안지훈(Ji-Hoon An),김상현(Sang-Hyun Kim),박준현(June-Hyune Prak) 대한전기학회 2021 전기학회논문지 Vol.70 No.2
This paper proposes a precise long-term trajectory prediction algorithm for the interception of highly maneuvering targets by a naval close-in-weapon system (CIWS). Ensuring satisfactory kill-probability, a target’s flight dynamics is described as the nonlinear differential equation with two slowly varying parameters. Our system model also contains the unknown control gains representing the general form of guidance laws, which can be modeled as random walk processes to cope with the versatile target maneuver in the terminal guidance phase. As a result, the long-term trajectory predictor is easily designed by applying the unscented Kalman filter for the probabilistic nonlinear state-space model. Through the simulations for typical ASM target engagement scenarios, it is demonstrated that the proposed filter is beneficial to improve the accuracy of the impact point calculation, which is necessary for the fire control algorithm of a CIWS.
차량용 2D 라이다를 이용한 특징정보 기반 확장표적추적 기법
함다혜(Dahye Ham),조형찬(Hyung-Chan Cho),윤유정(Yoo-Jung Yoon),나원상(Won-Sang Ra),한슬기(Seul-Ki Han) 대한전기학회 2021 전기학회논문지 Vol.70 No.1
This paper deals with the design problem of an extended target tracking filter using automotive 2D LIDAR. As a practical way to reduce the dimensionality of the LIDAR point cloud data and to extract an important target feature from it, the Hough transform is applied and the corresponding measurement equation is modeled. It is well-known that the pattern of the LIDAR point cloud varies with the relative geometry due to occlusion, which may leads the severe performance degradation in target tracking. To cope with this problem, a multiple model filter is designed by considering the measurement acquisition hypotheses on the target feature. Through the experiments in real-driving condition, the superior performance of the proposed filter over the existing method is demonstrated.