• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제19권3호
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• pp.327-364
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• 2015

In this paper, a generalized guidance law with an arbitrary pair of guidance coefficients for impact angle control is proposed. Under the assumptions of a stationary target and a lag-free missile with constant speed, necessary conditions for the guidance coefficients to satisfy the required terminal constraints are obtained by deriving an explicit closed-form solution. Moreover, optimality of the generalized impact-angle control guidance law is discussed. By solving an inverse optimal control problem for the guidance law, it is found that the generalized guidance law can minimize a certain quadratic performance index. Finally, analytic solutions of the generalized guidance law for a first-order lag system are investigated. By solving a third-order linear time-varying ordinary differential equation, the blowing-up phenomenon of the guidance loop as the missile approaches the target is mathematically proved. Moreover, it is found that terminal misses due to the system lag are expressed in terms of the guidance coefficients, homing geometry, and the ratio of time-to-go to system time constant.

• 한국추진공학회지
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• 제19권2호
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• pp.9-16
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• 2015

고체 추진제를 연료로 사용하는 DACS의 압력 및 추력을 동시에 제어하기 위한 제어기법을 제안하였다. 두 제어변수를 효과적으로 제어하기 위하여 각 변수의 물리적 특성을 고려한 연속형 루프 닫힘 구조를 적용하였고, 부정정 구조를 가진 제어명령을 효율적으로 분배하기 위하여 가중벡터를 이용한 의사 역행열 기법을 제안하였다. 아울러 높은 가속도를 안정적으로 획득하기 위하여 압력 유도기법을 종말 호밍구간에 적용함으로써 추력과 압력에 관한 명령 분배의 효용성을 입증하였다.

• 한국군사과학기술학회지
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• 제19권2호
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• pp.185-194
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• 2016

It is essential for generating the synthetic image to test and evaluate a guided missile system in the hardware-in-the-loop simulation. In order to make the evaluation results to be more reliable, the extent of fidelity and rendering performance of the synthetic image cannot be left ignored. There are numerous challenges to simulate the LWIR sensor signature of sea surface depending on the incident angle, especially in the maritime environment. In this paper, we investigate the key factors in determining the apparent temperature of sea surface and propose the approximate formula consisting of optical characteristics of sea surface and sky radiance. We find that the greater the incident angle increases, the larger the reflectivity of sea surface, and the greater the water vapor concentration in atmosphere increases, the larger the amount of sky radiance. On the basis of this information, we generate the virtual maritime environment in LWIR region using the SE-WORKBENCH, physically based rendering software. The margin of error is under seven percentage points.