• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.19 no.3
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• pp.235-252
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• 2015

Optimal impact angle control guidance law and its variants for intercepting a maneuvering target are introduced in this paper. The linear quadratic(LQ) optimal control theory is reviewed first to setup framework of guidance law derivation, called the sweep method. As an example, the inversely weighted time-to-go energy optimal control problem to obtain the optimal impact angle control guidance law for a fixed target is solved via the sweep method. Since this optimal guidance law is not applicable for a moving target due to the angle mismatch at the impact instant, the law is modified to three different biased proportional navigation(PN) laws: the flight path angle control law, the line-of-sight(LOS) angle control law, and the relative flight path angle control law. Effectiveness of the guidance laws are verified via numerical simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.9
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• pp.839-847
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• 2011

This paper proposes a new guidance law for increasing the lethality of munitions. The well known PNG (Proportional Navigation Guidance) is inadequate for the munitions because of some weaknesses. Even if the munition does not have the impact point error, the acceleration command is non zero because the line-of-sight changes at all times in flight. Therefore, we use a difference between a target and an impact point. This proposed guidance law is similar to PNG in the form, but this guidance law concentrates a correction rate of flight path angle instead of the LOS (Line of Sight) rate. The correction of flight path angle is defined as the amount of impact point error. This impact point error can be calculated by neural networks rapidly. Finally, we show that the simulation results prove the suitability of this law.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.4
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• pp.697-708
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• 2017

The complex battlefield environment makes it difficult to intercept maneuvering targets for guided missiles. In this paper, a finite-time convergent (FTC) guidance law based on the second-order sliding mode (SOSM) control theory is proposed to achieve the requirements of stability, accuracy and robustness. More specifically, a second-order sliding mode observer (SMOB) is used to estimate and compensate for the total disturbance of the controlled system, while the target acceleration is extracted from the line-of-sight (LOS) angle measurement. The proposed guidance law can drive the LOS angular rate converge to zero in a finite time, which means that the missile will accurately intercept the target. Numerical simulations with some comparisons are performed to demonstrate the superiority of the proposed guidance law.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.2
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• pp.146-152
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• 2014

In this paper, a new adaptive nonsingular terminal sliding mode control theory based impact angle guidance law for intercepting maneuvering targets was documented. In the design procedure, a new adaptive law for target acceleration bound estimation was presented, which allowed the proposed guidance law to be used without the requirement of the information on the target maneuvering profiles. With the aid of Lyapunov stability criteria, the finite-time convergent characteristics of the line-of-sight angle and its derivative were proven in theory. Numerical simulations were also performed under various conditions to demonstrate the effectiveness of the proposed guidance law.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.389-394
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• 1991

The surface-to-air missile system using Command to Line-Of-Sight (CLOS) guidance law is represented by complex nonlinear differential equations with 6 degree-of-freedom. This paper presents the characterictics of missile system and the effect of various error sources by Monte-Carlo simulation method. By simulation the part of playing a main role in the surface-to-air missile system is radar. Therefore for the performance of missile system the development of the technique reducing the error of radar is required. And the effect of accelerometer error is a few large, too. But, because accelerometer costs cheap this problem is solved easily. And the main error source of missile system data is the thrust, which affects directly to acceleration. The result is the important information about designing and fabricating missile system. And this makes the missile system best because of sharing elaborate and expense effectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.172-181
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• 2019

This paper deals with the problem of generating the energy optimal trajectory which is intended to enhance the target tracking performance of a passive homing missile. Noticing that the essence of passive target tracking is the range estimation problem, the target information gathered by passive measurements can be readily analyzed by introducing the range estimator designed in line-of-sight(LOS) frame. Moreover, for the linear filter structure of the suggested range estimator, the cost function associated with the target information is clearly expressed as a function of the line-of-sight rate. Based on this idea, the optimal missile trajectory maximizing the target information is obtained by solving the saddle point problem for an indefinite quadratic cost which consists of the target information and the energy. It is shown that, different from the previous heuristic approaches, the guidance command producing the optimal passive homing trajectory is produced by the modified proportional navigation guidance law whose navigation constant is determined by the weighting coefficient for target information cost.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.3
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• pp.281-292
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• 2014

We propose a novel cooperative guidance law design method based on the finite time disturbance observer (FTDO) for multiple near space interceptors (NSIs) with impact time control. Initially, we construct a cooperative guidance model with head pursuit, and employ the FTDO to estimate the system disturbance caused by target maneuvering. We subsequently separate the cooperative guidance process into two stages, and develop the normal acceleration command based on the super-twisting algorithm (STA) and disturbance estimated value, to ensure the convergence of the relative distance. Then, we also design the acceleration command along the line-of-sight (LOS), based on the nonsingular fast terminal sliding mode (NFTSM) control, to ensure that all the NSIs simultaneously hit the target. Furthermore, we prove the stability of the closed-loop guidance system, based on the Lyapunov theory. Finally, our simulation results of a three-to-one interception scenario show that the proposed cooperative guidance scheme makes all the NSIs hit the target at the same time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.506-514
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• 2012

This paper represents a method for designing of path following Line-of-Sight(LOS) guidance law based on vehicle kinematics. In general, a LOS guidance law which is composed of gains and approach length as design parameters is designed by empirical or trial-and-error method. These approaches cannot guarantee a precision tracking performance of guidance law consistently. Also, the design parameters should be redesigned with variations of vehicle maneuverability and flight velocity. Based on a vehicle kinematics with its velocity, the proposed method for designing of parameters not only minimizes the number of design parameters, also has a reliable and consistent tracking performance using variable guidance gain changed in accordance with flight velocity. This is validated by nonlinear simulation with $1^{st}$ order attitude response dynamics and flight experiments with given linear and circular path.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.156.3-156
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• 2001

This paper handles synthesis and investigation of a neural network guidance law based on pursuit-evasion games. This work considers two-dimensional pursuit-evasion games solved by using the gradient method. The procedure of developing a guidance law from the game-optimal solutions is deeply examined, and important features of the neural network guidance are investigated. The proposed neural network guidance law takes the range, range rate, line-of-sight rate, and heading error as its input variables. By reconstructing the trajectory, the accuracy of the neural network approximation is verified. Afterwards, robustness of the neural network guidance to the autopilot lag, which results from its feedback structure, is investigated ...

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.1
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• pp.124-131
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• 2005

This paper suggests LOS(Line-Of-Sight) guidance system of a surface vessel in straight-line navigation under ocean currents An LOS vector from the vessel to a point on the path between two way-points is decided and a heading angle is calculated to converge to follow the desired path based on the LOS vector This guidance system is called LOS guidance system. The suggested LOS guidance law has parameters to be properly chosen according to navigational environment. Parameters of LOS guidance system are optimized to reduce propulsive energy and/or position error between desired Position and present position of a ship using genetic algorithm which is a strong optimization algorithm with adaptational random search The effectiveness of the suggested LOS guidance system is assured through computer simulations.