• 전기전자학회논문지
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• 제25권4호
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• pp.766-769
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• 2021

딥러닝을 포함한 머신러닝 기법을 기반으로 비행체의 궤적 설계, 제어, 최적화, 예측 등의 작업을 수행하기 위해서는 일정한 양 이상의 비행체 궤적 데이터를 필요로 한다. 그러나 다양한 이유(예를 들어 비행체 궤적 데이터셋 구축에 필요한 비용, 시간, 인력 등)로 일정한 양 이상의 비행체 궤적 데이터를 확보하기 어려운 경우가 존재한다. 이러한 경우 합성 데이터 생성이 머신러닝을 가능하게 하는 방법 중 하나가 될 수 있다. 본 논문에서는 이와 같은 가능성을 탐구하기 위하여 시계열 생성적 적대 신경망을 이용하여 비행체 궤적 합성 데이터를 생성하고 평가하였다. 또한 비행체의 상태를 인식하기 위한 비행체 궤적 예측 작업에서 합성 데이터의 활용 가능성을 탐구하기 위하여 다양한 ablation study(비교 실험)를 수행하였다. 본 논문에서 제시된 생성 평가 및 비교 실험 결과는 비행체 궤적 합성 데이터 생성 및 비행체 궤적 관련 작업에서 합성 데이터의 활용 가능성에 대한 연구를 수행하고자 하는 연구자들에게 실질적인 도움이 될 것으로 예상한다.

• 시스템엔지니어링학술지
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• 제16권2호
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• pp.131-140
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• 2020

The characteristics of ballistic missiles are changing rapidly but studies have mostly focused on fragmentary flight trajectory analysis estimating the changing characteristics of some types, while there is a lack of research on comprehensive and efficient ballistic search, detection and prediction for missiles including the new types that have been gaining attention lately. This paper analyzes the flight trajectory characteristics of ballistic missiles at various ranges considering flight path angle adjustment, specific impulse and drag force with altitude based on the optimized equations of motion reflecting the parameters of North Korea's general and new types of ballistic missiles. The flight trajectory characteristics of representative ranges for each ballistic missile were analyzed by adjusting the flight path angle in the minimum energy method, lofted method, and depressed method. In addition, High value target can attacked by ballistic missiles considering flight path angle adjustment at various points. It's expected to be used to Threat Evaluation and Weapon Allocation, and deployment of defense systems by interpreting the analysis of the latest Iskander-class ballistic missiles and the new multiple rocket launcher.

• 한국항공운항학회지
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• 제20권2호
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• pp.1-6
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• 2012

Four dimensional(4-D) trajectory modeling is conducted based on flight plan. The flight plan is divided into several segments which represent certain operating flight modes. Thrust, drag and fuel consumption rate of an aircraft are calculated using BADA provided by Eurocontrol. The trajectory is modeled with the rate of climb/descent calculated with Total-Energy Equation. The simulation results with a typical aircraft and its flight plan indicate that the trajectory modeled corresponds well with the suggested flight plan. The performance profiles including total endurance time and time history for speed, thrust, drag and fuel consumption were also appropriately generated.

• International Journal of Aerospace System Engineering
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• 제3권2호
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• pp.14-21
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• 2016

This paper presents research on predicting the possible intercept time for a Nodong missile based on its flight trajectory. North Korea possesses ballistic missiles of various ranges, and nuclear warhead miniaturization tests and ballistic missile launch tests conducted last year and in previous years have made these missiles into a serious security threat for the international community. With North Korea's current miniaturization skills, the range of the nuclear capable Nodong missiles can be adjusted according to their use goals and operating environment by using a variety of adjustment methods such as payload, fuel mass, Isp, loft angle, cut-off, etc., and therefore precise flight trajectory prediction is difficult. In this regards, this research performs model simulations of the flight trajectory of North Korea's domestically developed Nodong missiles and uses these as a basis for predicting the possible intercept times for major ballistic missile defense systems such as PAC-3, THAAD, and SM-3.

• 한국국방경영분석학회지
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• 제32권1호
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• pp.176-187
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• 2006

탄도미사일은 비행속도가 매우 빠르고 불안정한 하강운동에 기인하는 나선형과 같은 고유의 특이한 비행운동으로 인해 정확한 비행궤적의 추정이 어렵다. 이 논문은 탄도미사일의 비행궤적 특성에 대한 종합적인 해석을 기술한다. 최대사거리를 포함 다양한 미사일 비행사거리에 따른 비행궤적특성이 해석적 방법에 의해 도출되었다. 최대사거리를 줄여 발사했을 때 비행특성에 따른 위협이 급격히 증가됨을 해석적으로 나타냈다. 이 연구는 하층미사일방어체계 구축의 운용개념 설정에 대한 기반연구이다.

• 한국군사과학기술학회지
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• 제18권2호
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• pp.173-180
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• 2015

North Korea has developed ballistic missiles over the past 30 years. It is believed that they have a variety of ballistic missiles more than 1,000. Because these ballistic missiles threaten South Korea directly, accurate analysis of them is essential. Flight trajectories of the ballistic missiles are generally changed by means of adjusting payload weight, Isp, flight path angle, and cut-off time. The flight path angle is widely used to control the missile range. However it is difficult to predict the missile trajectory exactly in real operational environment because the missile could be launched according to its intention and purpose. This work analyzed the 1,000 km range MRBM's trajectory characteristics from adjusting flight path angle which is depressed as well as lofted method. The analysis of missile trajectory characteristics is based on the simulation of the missile trajectory model developed by KNDU research team.

• 한국시뮬레이션학회논문지
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• 제27권4호
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• pp.1-8
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• 2018

인공지능을 이용하여 목표 지점까지 제어하는 가장 대표적인 방법은 강화학습이다. 하지만 그동안 강화학습을 처리하기 위해서는 구현하기 어렵고 복잡한 연산을 처리해야만 했다. 본 논문에서는 이를 개선한 Proximal Policy Optimization (PPO) 알고리즘을 이용하여 가상환경에서 목표지점에 도달하기 위한 계획된 비행궤적을 찾는 방법을 시뮬레이션 하였다. 또한 외부 환경요소가 비행궤적 학습에 미치는 영항을 알아보기 위하여 궤적의 변화, 보상 값의 영향 및 외부 바람등과 같은 변수를 추가하고 궤적 학습 성능 및 학습 속도에 미치는 영향을 비교 분석을 수행한다. 본 결과를 통하여 에이전트가 다양한 외부환경의 변화에도 계획된 궤적을 찾을 수 있다는 것을 시뮬레이션 결과에 따라 알 수 있었으며, 이는 실제 비행체에 적용할 수 있을 것이다.

• 제어로봇시스템학회논문지
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• 제9권6호
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• pp.478-488
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• 2003

A guidance scheme that is suitable for controlling the aircraft flight path is proposed. The concept of miss distance which is commonly used in the missile guidance laws, and Lyapunov stability theorem are effectively combined to obtain the aircraft's trajectory-tracking guidance law. Guidance commands are given in terms of speed and flight path angles, but they perfectly reflect any position and velocity errors between real aircraft trajectory and reference one. The proposed guidance law is easily integrated into the existing flight control system. The new guidance law was extensively tested with various mission scenarios and the fully nonlinear 6-DOF aircraft model. Furthermore, the new guidance law was compared with previous guidance schemes in nonlinear simulation. Results from the numerical simulation show that the proposed guidance law yields better performance than previous ones.

• International Journal of Aeronautical and Space Sciences
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• 제9권2호
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• pp.71-78
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• 2008

New formation flight controller for unmanned aerial vehicles is proposed. A behavioral decentralized control approach called formation geometry center control is adopted. Trajectory tracking as well as formation geometry keeping are the purpose of the formation flight, and therefore two controllers are designed: a trajectory tracking controller for reference trajectory tracking, and a position controller for formation geometry keeping. Each controller is designed using Lyapunov stability theorem to guarantee the asymptotic stability. Formation flight controller is finally obtained by combining the trajectory tracking controller and the formation geometry keeping controller using a weighting parameter that depends on the relative distance error between unmanned aerial vehicles. Numerical simulations are performed to validate the performance of the proposed controller.

• International Journal of Aeronautical and Space Sciences
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• 제14권3호
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• pp.247-255
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• 2013

The flight control of re-entry vehicles poses a challenge to conventional gain-scheduled flight controllers due to the widely spread aerodynamic coefficients. In addition, a wide range of uncertainties in disturbances must be accommodated by the control system. This paper presents the design of a roll channel controller for a non-axisymmetric reentry vehicle model using the trajectory linearization control (TLC) method. The dynamic equations of a moving mass system and roll control model are established using the Lagrange method. Nonlinear tracking and decoupling control by trajectory linearization can be viewed as the ideal gain-scheduling controller designed at every point along the flight trajectory. It provides robust stability and performance at all stages of the flight without adjusting controller gains. It is this "plug-and-play" feature that is highly preferred for developing, testing and routine operating of the re-entry vehicles. Although the controller is designed only for nominal aerodynamic coefficients, excellent performance is verified by simulation for wind disturbances and variations from -30% to +30% of the aerodynamic coefficients.