• The Journal of the Acoustical Society of Korea
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• v.41 no.2
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• pp.210-217
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• 2022

Passive source depth estimation has been studied for decades since the source depth can be used for target classification, target tracking, etc. The purpose of this paper is to solve the problem of ambiguity in the previous paper [S.-il. Cho et al. (in Korean), J. Acoust. Soc. Kr. 38, 120-127 (2019)] that source depth is estimated in two points. The patterns of phase shift of Channel Impulse Response(CIR) reflected in ocean surface and bottom is used for removing ambiguity of the source depth estimation, and after removing ambiguity, source depth is estimated at one point through the intersection of CIR. In order to extract CIR in case of unknown source signal and continuous signal or noise, Ray-based blind deconvolution is used. The proposed algorithm is demonstrated through numerical simulation in ocean waveguide.

• Journal of the Korea Society of Computer and Information
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• v.29 no.2
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• pp.119-126
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• 2024

The IISS(Integrated Interface Storage System) software performs the function of transmitting tactical domain messages of Combat Management System for interface analysis of Naval Combat System. The source code is relatively large because the IISS software handles most messages. The modifications of source code of the IISS software occur frequently due to changes in interconnected equipment and messages. Therefore, additional effort and cost are required during the development process. In this paper, we studied standardization of the IISS software to improve reusability. Through the feature model, the components of the IISS software were divided by function and modification elements were separated. And the structure of the IISS software was improved by applying design patterns. As a result, it was possible to minimize modifications of the IISS software by changes in interconnected equipment and messages and a reduction in development costs could be expected.

• Journal of Advanced Navigation Technology
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• v.28 no.2
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• pp.178-184
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• 2024

The radar installed on an aircraft has various operating modes depending on tactical purposes, allowing for the configuration of search areas according to each mode's operational objectives. active electronically scanned array (AESA) radar emits search beams sequentially according to a predefined search beam grid within the designated search area specified by the pilot to detect targets within it. It is crucial that the radar can stably search the area designated by the pilot for target detection, even as the aircraft's attitude changes. This paper focuses on stabilizing the search pattern in the air-to-air operational mode of aircraft-mounted radar to ensure stable target detection during roll and pitch maneuvers of the aircraft. The paper demonstrates its performance by simulating aircraft maneuvers and targets in a system integration laboratory (SIL) test environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.483-491
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• 2015

This paper describes the design optimization of parasitic elements used for TACAN broadband antenna. We deployed parasitic elements arranged in a circular array to electronically rotate the antenna instead of employing a mechanically rotated antenna to generate the composite radiation pattern of 15 Hz and 135 Hz including bearing information and to meet the harmonic contents specification of MIL-STD-291C. We performed the simulation for optimization of the parasitic elements and fabricated the antenna composed of 16 parasitic elements of 15 Hz and 63 parasitic elements of 135 Hz. With harmonics magnitude reduction by increasing the number of steps using vector composition of the reflectors, the measured result meets the specification of MIL-STD-291C.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.6
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• pp.572-578
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• 2007

A Rigid Inflatable Boat (RIB) is now widely used for commercial and military purpose. In this paper, it is supposed that seven-meter-class RIB be used as an unmanned target ship for naval training. In order to develop many tactical maneuvering patterns of a target ship, a simple horizontal maneuvering model of a RIB is needed. Therefore, models of speed and yaw rate are constructed as the first-order differential equations based on Lewandowski#s empirical formula for steady turning circle diameter of a conventional planning hull. Some parameters in the models are determined using the results of sea trial tests. Finally, proposed models are validated through the comparison of the simulation result with the sea trial result for a specific scenario. Even though a simple model does not represent the horizontal motion of a RIB precisely, however, it can be used enough to develop tactical trajectory patterns.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.9
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• pp.811-820
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• 2012

GNSS signal is vulnerable to jamming signal because of well-known signal structure and weak signal power. For these reasons, the need for analysis of jamming effects and anti-jamming techniques of is increasing. In this paper, a GNSS signal generator is designed which includes a radio wave propagation model for six kind of tactical environments and a body masking model for the reception environment of a vehicle. The radio wave propagation model for downtown, rural, forest, coastline, waste land and snow or ice area is designed using two-ray model. The body masking model is designed the effect which the antenna is affected by the reception environment of a vehicle and radiation pattern from a user configuration. The performance of generated signals from the GNSS signal generator considering reception environment of a vehicle is evaluated by a commercial GPS L1 receiver(NordNav) in normal and jamming environment. Also, the generated GNSS signal is compared to a commercial GPS L1 H/W based RF signal generator(STR4500). The results show that the designed GNSS signal generator in a normal environment compared to the same navigation performance. In jamming environment, it is shown that the body masking effect and GNSS signal acquisition and tracking loss in compliance with the jamming signal are precisely working in the reception environment of a vehicle.