• Korean Journal of Optics and Photonics
• /
• v.32 no.4
• /
• pp.153-162
• /
• 2021

In this article, the design of a variable F-number and triple magnification infrared optical system is described. That is a two-in-one optical system that combines an infrared search and track (IRST) system and an electro-optical tracking system (EOTS), where an afocal optical system is added to the IRST optical system designed already. The performance target is determined by analyzing system performance, and then the specification in the optical system design is calculated. This optical system contains a warm stop making it possible that one optics has two different F/# by cutting the size of aperture, and that is designed to suit this optics. The system satisfies the requirement such as a modulation transfer function (MTF). For operational assessment, the movement of the focusing lens group is analyzed over the change of temperature and target distance. By using this optical system, it is possible to develop equipment having two functions, infrared searching and electro-optical tracking.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.2
• /
• pp.329-335
• /
• 2019

Reliability growth analysis was conducted for a guided weapons system. In the development phase, reliability management activities were continuously carried out by identifying failure modes and causes and analyzing faults found during the testing. The missile system consists of an all-up-round missile and a launcher, and the analysis was carried out according to the test results of each system. The test results for the all-up-round missile were obtained with discrete data, which were success and failure as a one-shot-device. The test results for the launcher were obtained with continuous data by operating the equipment continuously in the test. For each test result, the reliability growth model was applied to the Standard Gompertz model and the Crow-Extended model. The models were used to identify the growth analysis results of the test so far. It was also possible to predict the reliability growth results by assuming the future test results. The study results could be useful in achieving the desired reliability goal and in determining the number of tests. Then, the planned test will be confirmed and the growth analysis of the missile system will continuously be conducted.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.28 no.6
• /
• pp.1449-1461
• /
• 2018

As the number of software vulnerabilities grows year by year, attacks on software are also taking place a lot. As a result, the security administrator must identify and patch vulnerabilities in the software. However, it is important to prioritize the patches because patches for all vulnerabilities are realistically hard. In this paper, we propose a scoring system that expands the scale of risk assessment metric by taking into consideration attack patterns or weaknesses cause vulnerabilities with the vulnerability information provided by the NIST(National Institute of Standards and Technology). The proposed scoring system is expanded based on the CWSS and uses only public vulnerability information to utilize easily for any company. In this paper, we applied the automated scoring system to software vulnerabilities, and showed the expanded metrics with consideration for influence of attack pattern and weakness are meaningful.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.5
• /
• pp.485-491
• /
• 2019

In this paper, we present a process and case of RAM analysis using Field-Data of the ground weapon system in operation in the army. In order to perform RAM analysis in filed-Data, we propose data collection, data refining and calibration, and RAM analysis process. RAM analysis was performed with the RAM verification and evaluation system developed by Defense Agency for Technology and Quality. We enhance the objectivity and reliability in result of data, which contains a variety of conditions; operation and maintenance concept of domestic ground weapon system, relevant regulation and after-sales service data of developer. Results are compared 2015, 2018 and development RAM value. We prove results of RAM analysis through discussion experts. Studies show that proposed method can effectively apply database from setting to evaluation RAM value in various ground weapon system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.30 no.1
• /
• pp.79-87
• /
• 2019

Radar detection range is decreased with an increase in the noise levels and detection thresholds in adaptive CFAR of a radar signal processor to the weather clutter reflection signal in the rain. When a high-velocity plot is generated in weather clutter, what are detected are not targets but false plots. Detection opportunity is reduced by radar time resource consumption from additional confirmations regarding the false plots. In this paper, the received signals are saved using a radar-received signal storage device. Based on the analysis of the received signals from weather clutter, the influence of the rainfall reflection has been mitigated by front-end attenuation of the signal processor. The improvement in the detection performance is verified through received signal and simulation results.

• Journal of Advanced Navigation Technology
• /
• v.23 no.3
• /
• pp.245-250
• /
• 2019

Inertial navigation system has navigation errors because of the error of inertial measurement unit (IMU) and misalignment over time. In order to solve this problem, aided navigation system is performed using global navigation satellite system (GNSS), speedometer, etc. The inertial navigation system equipped with underwater vehicle mainly uses speedometer and performed aided navigation because satellite signals do not pass through underwater. There are DVL, EM-Log, and RPM in the speedometer, and the sensors are applied according to the system environment. This paper describes velocity aided navigation using RPM of inertial navigation system operating in high speed and deep water environment. In addition, we proposes an algorithm to compensate the limit of RPM with straight direction and the current velocity error. There are results of monte-calo simulation to prove performance of the proposed algorithm.

• Convergence Security Journal
• /
• v.18 no.4
• /
• pp.62-71
• /
• 2018

The rapid growth of virtual reality technology in the era of the 4th Industrial Revolution has accelerated scientification of combat training systems in addition to ICT(information and communications technology) in military field. Recently, research and development of simulators based on virtual reality have been actively conducted in order to solve sensitive issues such as increase of civil complaints due to the noise of a shooting range, prevention of shooting accident, and reduction of training cost. In this paper, we propose two key solutions: spatial synchronization method and modified point mass trajectory model with small angle approximation to overcome technical limitations of a current training simulator. A trainee who wears a haptic vest in a mixed reality environment built in MARS(medium-range assault rifle shooting simulator) is able to conduct not only precision shooting but also two-way engagement with virtual opponents. It is possible for trainee to receive more reliable evaluations in the MARS than an existing rifle simulator based on laser.

• Convergence Security Journal
• /
• v.18 no.4
• /
• pp.73-79
• /
• 2018

Since 1910s, the drones were mainly used for military purposes for reconnaissance and attack targets, but they are now being used in various fields such as disaster prevention, exploration, broadcasting, and surveillance of risk areas. As drones are widely used from military to civilian field, hacking into the drones such as radio disturbance, GPS spoofing, hijacking, etc. targeting drones has begun to occur. Recently, the use of drones in hacking into wireless network has been reported. If the artificial intelligence technology is applied to the drones in the military, hacking into unmanned combat system using drones will occur. In addition, a drone with a hacking program may be able to relay a hacking program to the hacking drone located far away, just as a drone serves as a wireless communication station. And the drones will be equipped with a portable GPS jamming device, which will enable signal disturbance to unmanned combat systems. In this paper, we propose security threats and the anticipated hacking scenarios using the drones on the battlespace to know the seriousness of the security threats by hacking drones and prepare for future cyberspace.

• Journal of Advanced Navigation Technology
• /
• v.23 no.2
• /
• pp.142-150
• /
• 2019

Muzzle Velocity is one of the most important measurement items for evaluation of ammunition. The muzzle velocity is defined as the velocity when the projectile leaves the muzzle. Particularly, since the muzzle velocity is closely related to the performance of the propellant, precise measurement of muzzle velocity is required. Doppler radar is used to measure the muzzle velocity, but the quality of Doppler radar signal depends on the test site environment. In this paper, a method to remove the clutter that degrades the signal quality of Doppler radar by improving the structure of the test site and the signal processing method is suggested. For the application of the improved signal processing method, a program for acquiring Doppler radar's raw Doppler data was created. Statistical verification of the velocity data obtained through the improvement of the test site structure and signal processing method proved that the proposed method is effective for the removal of clutter as compared with the existing method.

• The Journal of the Acoustical Society of Korea
• /
• v.38 no.4
• /
• pp.371-377
• /
• 2019

In this paper, we present the sea trial results of long distance underwater acoustic communication in the East Sea, October 2018. One transmitter and sixteen vertical array receivers were used to collect underwater acoustic communication signals, and the maximum distance between the transmitter and the receiver was 90 km. Information was transmitted by BFSK (Binary Frequency Shift Keying) and BCSK (Binary Chirp Shift Keying) method, which are typical digital frequency modulation techniques. Experimental results show that there is no error in all cases at the transmission distance of 60 km, and BFSK and BCSK have average uncoded bit error rate of 0.0197 and 0.0007 respectively without channel coding at 90 km transmission distance.