• 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 Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.404-413
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• 2015

The target classification for ballistic target(BT) is one of the most critical issues of ballistic defence mode(BDM) in multi-function radar(MFR). Radar responds to the target according to the result of classifying BT and air breathing target(ABT) on BDM. Since the efficiency and accuracy of the classification is closely related to the capacity of the response to the ballistic missile offense, effective and accurate classification scheme is necessary. Generally, JEM(Jet Engine Modulation), HRR(High Range Resolution) and ISAR(Inverse Synthetic Array Radar) image are used for a target classification, which require specific radar waveform, data base and algorithms. In this paper, the classification method that is applicable to a MFR system in a real environment without specific waveform is proposed. The proposed classifier adopts kinematic data as a feature vector to save radar resources at the radar time and hardware point of view and is implemented by fuzzy logic of which simple implementation makes it possible to apply to the real environment. The performance of the proposed method is verified through measured data of the aircraft and simulated data of the ballistic missile.

• Convergence Security Journal
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• v.19 no.3
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• pp.109-115
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• 2019

The North's short-range projectiles and missiles are the Iskander-class missiles of the S-300 series, with a range of 270-420 kilometers and an altitude of 40-50 kilometers, making it very difficult to respond with South Korea's detection radar or striking weapons. The North's handling of the Seoul sea of fire also makes it very urgent for the South to deploy the weapons to power or introduce them as soon as possible, as it can identify its intention to strike the Seoul metropolitan area by equipping such short-range rockets and missiles with nuclear or chemical weapons. We will be prepared to prep are for reckless provocations by securing our own technology by continuously developing the Korean missile defense system and striking system, Kill Chain, which is designed to defend short-range missiles in the long-term, and securing our own technology.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.1
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• pp.10-21
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• 2023

For various target tracking applications, it is well known that the Kalman filter is the optimal estimator(in the minimum mean-square sense) to predict and estimate the state(position and/or velocity) of linear dynamical systems driven by Gaussian stochastic noise. In the case of nonlinear systems, Extended Kalman filter(EKF) and/or Unscented Kalman filter(UKF) are widely used, which can be viewed as approximations of the(linear) Kalman filter in the sense of the conditional expectation. However, to implement EKF and UKF, the exact dynamical model information and the statistical information of noise are still required. In this paper, we propose the recurrent neural-network based Kalman filter, where its Kalman gain is obtained via the proposed GRU-LSTM based neural-network framework that does not need the precise model information as well as the noise covariance information. By the proposed neural-network based Kalman filter, the state estimation performance is enhanced in terms of the tracking error, which is verified through various linear and nonlinear tracking problems with incomplete model and statistical covariance information.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.3
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• pp.262-272
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• 2023

A polymer-based mechanical low-pass filter(m-LPF) for high-g accelerometers makes it possible to remove high-frequency transient noises from acceleration signals, thus ensuring repeatable and reliable measurement on high-g acceleration. We establish a prediction model for performance of m-LPF by combining a fundamental vibration model with the fractional derivative standard linear solid(FD SLS) model describing the storage modulus and loss modulus of polymers. Here, the FD SLS model is modified to consider the effect of m-LPF shape factor (i.e., thickness) on storage modulus and loss modulus. The prediction accuracy is verified by comparing the displacement transmissibility(or cut-off frequency) estimated using our model with that measured from 3 kinds of polymers(polysulfide rubber(PSR), silicone rubber(SR), and polydimethylsiloxane(PDMS)). Our findings will contribute a significant growth of m-LPF for high-g accelerometers.

• Journal of The Korean Institute of Defense Technology
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• v.5 no.4
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• pp.1-8
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• 2023

In this study the economic impact of each plan for introducing Korea unclear-powered submarines were analyzed. This study conducted a preliminary investigation into foreign countries cases of unclear-powered submarines and classified three introduction plans. In order to analyze the economic impact of each introduction plan, a multiple-level survey was conducted targeting experts with experience in developing and operating ship weapon systems, and quantitative results were calculated for subcategory items with industrial relevance for industrial correlation analysis. The value added inducement coefficient and production inducement coefficient and employment inducement coefficient were calculated for each introduction method, and a favorable introduction method was derived. It is hoped that the results of this study will serve as a reference for policy decision-making during prior research for the introduction of korea nuclear submarines.

• Convergence Security Journal
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• v.23 no.4
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• pp.141-151
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• 2023

Since the end of the Cold War in the 1990s, European countries have cut defense costs and reduced armaments as an era of peace without large-scale wars continues, and as a result, the West's defense industry base has gradually weakened. On the other hand, South Korea, the world's only divided country, was able to achieve high growth in the defense industry as a result of continuous arms strengthening in the face of North Korea's nuclear and missile threats. With the rapid increase in demand for conventional weapons systems and changes in the structure of the global defense market due to the Russia-Ukraine war, Korea's weapons system drew great attention as a large-scale defense export contract with Poland was signed in 2022. In 2023, K-Defense ranked ninth in the world's arms exports and aims to become the world's fourth-largest defense exporter by 2027. Therefore, this study analyzed the case of Korea-Poland defense exports to derive problems, and presented development strategies related to export revitalization of K-Defense, a national strategic industry. In order for the defense industry to become Korea's next growth engine, it is necessary to establish a defense organization, prepare government-level measures to protect defense industry technology, and expand military and security cooperation with allies linked to defense exports.

• Journal of National Security and Military Science
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• s.13
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• pp.43-81
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• 2016

Security environment we face in the Korean Peninsula is unexpectable. Tensions between Seoul and Pyeongyang and its threats are continuously evolving. Kim Jung Un will keep on conducting provocations and DPRK's isolation will result uncertainty to their objective and intention. KPA is centered on ground forces with conventional weapons but they possess modernized missiles and nuclear capabilities. What's more concerning is that North Korea continuously pursue and develop nuclear weapons and missile capabilities. Pursuing defense reform is inevitable for the ROK to deal adequately against the security threats posed by the North and to prepare for the environment of future warfare. If we are satisfied with the current capabilities then our military capabilities and security status will retrogress. We have to reorganize our units to make a small but FMC, smart military organization. Organization analysis is an urgent issue for reorganizing units. However, it isn't an easy task to reform an organization. There are vague parts for analysis and strong resistance from the people within the organization. Therefore should not focus on the reduction of people and the organization. Organization reform should be done with the acknowledgement of most of the personnel and should focus on the task and its method. These should be reflected to the organization analysis.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.3
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• pp.370-378
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• 2018

The mission data in missile systems should be quickly and reliably transmitted from a mission transmission device to a guidance control unit. The MIL-STD-1553B is one of the reliable communication standards, but its bit rate is generally limited to 1Mbps due to the intrinsic properties of its electrical design. Therefore, the bus controller needs to be optimized to efficiently transmit the mission data on the inevitably limited bit rate. This paper proposes an analytical approach based on sampling-based optimization methods to maximize the data throughput without data loss. The proposed approach was evaluated in the simulations with the data transmission model for the MIL-STD-1553B communication system. The results of the proposed methods were applied to a real-time system and showed that the proposed method was successfully performed.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.716-723
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• 2019

It is crucial to understand the characteristics of cloud occurrence frequency for development of high precision guided missile using infrared imaging sensor. In this paper, we investigated the vertical structure of cloud for altitude using upper-air observation data. We find that cloud occurrence frequency is high at altitudes of 1.3 km and 9.5 km. Theses features have seasonal and temporal dependency. In the summer, cloud often occur more than average regardless of altitude. In the winter, low clouds occur frequently, and high clouds do not occur well. In temporal characteristics, clouds occur more frequently in daytime than in nighttime regardless of altitude. Many of clouds exist in single layer or double layers in the air. We also find that the 40 % of cloud occurrence frequency at high altitude when low clouds under altitude of 2 km cover entire sky.