• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.2
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• pp.255-263
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• 2017

An infrared-guided missile has been emerging as a major threat against combat aircraft due to its passive guidance characteristics and with recent advances in stealth technology. Hence, the infrared stealth technology and its effectiveness-evaluation technique become more significant than ever before. In this study, we applied missile aerodynamics to lethal range calculation which allowed more precise prediction. CFD analyses were newly involved in estimating drag force characteristics of an infrared-guided missile. Velocity profiles during flight period of the missile were constructed utilizing these drag characteristics and then incorporated into our in-house code to predict corresponding lethal ranges. The results showed that the present method can predict lethal range more appropriately than the previous one with constant velocity profile. As one of the results, if a fighter gains altitude more which reduces less drag of the attacking missile, then the lethal envelope increases significantly more compared to the lock-on envelope.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.101-106
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• 2002

In a bank-to-turn(BTT) missile, if a 2-gimbaled seeker was stabilized using a 2-axis rate gyro mounted along its primary axis, the change of line of sight(LOS) measured by the seeker would be induced by rolling effects due to bank-to-turn(BTT) steering as well as an actual change. It is observed that the body-coupled effects in a homing loop of BTT missile are mainly concerned with the spurious target maneuver and the coupling due to the rate gyro misalignments. In this paper, we formulate a simple linear BTT homing loop model with seeker model including each body-coupling. With the model, we analyze the effects of the couplings on the homing loop stability, and propose a direct linear compensator for the coupling to recover the stability.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.597-602
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• 1988

In this paper, we consider conventional and modified proportional navigation guidance(PNG) laws for a random maneuvering target. By means of Lyapunov function approach, we show that an ideal missile guided by the conventional PNG law can always intercept a random maneuvering target if some specified initial conditions are satisfied and the navigation constant is chosen sufficiently high. In addition, we propose a modified PNG law. At the final phase of pursuit, the proposed guidance law has a better acceleration profile than the conventional PNG law.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.190-196
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• 2013

This paper proposes a new guidance law, which considers the Field of View (FOV) of the seeker when a missile has a strapdown seeker mounted instead of a gimbal seeker. When a strapdown seeker, which has a narrow FOV, is used for tracking a target, the FOV of the seeker is an important consideration for guidance performance metrics such as miss distance. We propose a new guidance law called hybrid guidance (HG) to address the shortcomings of conventional guidance laws such as proportional navigation guidance (PNG), which cannot maintain lock-on conditions against high speed targets due to the narrow FOV of the strapdown seeker. The aim of the HG law is to null miss distance and to maintain the look angle within the FOV of the strapdown seeker. In order to achieve this goal, we combine two guidance laws in the HG law. One is a PNG law to null the LOS rate, and the other is a sliding mode guidance (SMG) law derived to keep the look angle within the FOV by employing a Lyapunov-like function with a sliding mode control methodology. We also propose a method to switch these two guidance laws at certain look angles for better guidance performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.7
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• pp.633-639
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• 2007

This paper presents a new homing guidance law based on well-known BPN to achieve an impact time constraint as well as an impact angle constraint. The guidance commands are synthesized by introducing an additional command to control impact-time. The structure of the additional command has a BPN-based loop multiplied by time-varying gains being proportional to the time difference between the required time-to-go and the estimated time-to-go by BPN. Moreover, the proposed homing loop converges to BPN as the time-to-go error is reduced. The performance of the proposed guidance law is evaluated by the computer simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.5
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• pp.373-382
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• 2013

In this paper, in order to analyze the performance of a decoy system for ship defense against an anti-ship missile(ASM) with an infrared image(IIR) seeker, the modeling and engagement simulation program is introduced. The IIR seeker on the ASM detects the infrared signal of ship from a distance and approaches the ship based on proportional navigation guidance(PNG) or impact angle control guidance(IACG). Hence the guidance performance of the ASM is basically depend on the target tracking algorithm of the seeker as well as the infrared signal of the ship. Using the developed program, we can investigate the effect of the ship decoy system such as flares and surface cooling system of the ship with respect to various kinds of tracking algorithms of the IIR seeker of the ASM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1659-1666
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• 2010

The High maneuver missiles use various interfaces and high speed guidance and control loop. Hardware-in-the-Loop(HWIL) simulation control system, therefore, should have high performance computing power and hardware interface capabilities, and should be developed using IT technology with which real time operating system, embedded system, data communication technology, and real time hardware control are integrated. This paper suggests the control system design techniques, such as a system hardware configuration, a job distribution algorithm for high performance multi-processors, a real time calculation and control mechanism, inter-processor communication mechanism, and a real time data acquisition technique, to perform the HWIL simulation for high maneuver missile system.

• Advances in aircraft and spacecraft science
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• v.10 no.4
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• pp.317-334
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• 2023

This paper presents a basic methodology and a set of numerical tools for the preliminary design of solid-fueled ramjet missiles. An elementary code determines the baseline system configuration comprised of warhead, guidance-control, and propulsion masses and geometries from specific correlations found in the literature. Then, the system is refined with the help of external and internal ballistics codes. Equations of motion are solved for the flight's ascending, cruising, and descending stages and the internal ballistic set of equations designs the ramjet engine based on liquefying fuels. The combined tools sized the booster and the ramjet sustainer engines for a long-range missile, intended to transport 200 kg of payload for more than 300 km range flying near 14,000 m altitude at Mach 3.0. The refined system configuration had 600 mm in diameter and 8,500 mm in length with overall mass of 2,128 kg and 890 kg/m3 density. Ramjet engine propellant mass fraction was estimated as 74%. Increased missile range can be attained with paraffin-polyethylene blend burning at near constant regression rate through primary air mass flow rate control and lateral 2-D air intakes.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.6
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• pp.776-784
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• 2009

The function of DIRCM(Directed Infrared Countermeasures) jamming is to cause the missile to miss its intended target by disturbing the seeker tracking process. The DIRCM jamming uses the pulsing flashes of IR energy and its frequency, phase and intensity have influence on the missile guidance system. In this paper, we analysis the DIRCM jamming effect of spin-scan reticle seeker. Simulation results show that the jamming effect is greatly influenced by frequency, phase and intensity of the jammer signal.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.5
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• pp.52-58
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• 2011

The missile control system is comprised of various control systems such as autopilot, guidance law, and homing filter and so on. To design these guidance and control system, the optimization technique is widely applied at each developing stage. However, this kind of optimization requires lots of time and cost and moreover, this approach does not give an overall system optimization result. In this paper, to use the optimization tool for control system design, the optimal problem formulation is done and the performance index and constraints are considered. And finally the systematically optimized method is proposed.