• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.251-256
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• 2004

A stable reference voltage generator is necessary to the infrared image signal readout circuit(ROIC) to improve noise characteristics in comparison with signals originated from infrared devices, that is, to gain good images. In this study, bandgap reference circuit operating at cryogenic temperature of 77K for Infrared image ROIC(readout integrated circuit) was propose. Most of bandgap reference circuits which are presented so far operate at room temperature, and they are not suitable for infrared image ROIC operating at liquid nitrogen temperature, 77K. To design bandgap reference circuit operating at cryogenic temperature, the parameter characteristics of used devices as temperature change are seen, and then bandgap reference circuit is proposed with considering such characteristics. It demonstrates practical use possibility through taking measurements and estimations.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.68-74
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• 2009

Infra-red earth sensors(IRES) are accommodated in a geostationary multi-functional satellite, which includes optical payloads for observing the earth, to provide pointing reference for the payloads. Even the slight pointing difference between the IRES and the payloads is so critical from the geostationary orbit that can degrade their imaging performance. Therefore, a dedicated support structure is required to guarantee the stability during the flight operation. This paper shows the design justification for the IRES support structure employed in the Communication, Ocean and Meteorological Satellite(COMS). It intends to give an overall design presentation and to justify that this design is compatible with all the requirements in terms of stiffness and strength as well as the stability.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.6
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• pp.917-922
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• 2013

In this paper, we propose a smoke detection system in order to detect a fire in a wide space, such as tunnel, airports using infra-red and visible laser. The proposed smoke detection system is composed of infra-red laser transmitter and receiver, visible laser and Zigbee wireless communication network. A visible laser is used to match transmitter and receiver and Zigbee network is utilized to propagate warnings of fire. If smoke is appeared between transmitter and receiver, received signals are decreased and it can be considered as occurring smoke. As IR laser transmitter and receiver are separated by long distance, it is difficult to match due to large variations caused by small change of direction. In this paper, it is proposed to match effectively using visible laser. When smoke is detected, warning informations are propagated by Zigbee network in the developed smoke detection system.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.679-685
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• 2005

Until now, the stealth design to reduce the infrared signature of ship haven't been carried out using the proper design criteria. The study on the maritime meteorological environment in the Korean seas hasn't been accomplished yet, so the design criteria of the maritime meteorological environment was just given by the engineering sense without experience of the Navy and/or of the shipyard. Even in rather good conditions(summer condition), the estimated IR signature of a ship showed larger values and couldn't predict the worst condition during the operation of a ship at sea. In this study, domestic maritime meteorological data were collected and variables affecting the IR signature of a ship had been derived through the sensitivity study of IR signature according to the maritime meteorological environment in Korean seas. The basic study on the criteria of the stealth design of IR signature has been carried out.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.4
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• pp.336-341
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• 2013

In this paper, the design concept of a low-temperature vacuum blackbody was described, and thermophysical model of the blackbody was numerically evaluated. Also the working performance of low-temperature vacuum blackbody was evaluated using infrared camera system. The blackbody system was constructed to operate under high-vacuum conditions ($2.67{\times}10^{-2}$ Pa) to reduce temperature uncertainty, which is caused by vapor condensation at low temperatures usually below 273 K. In addition, both heat sink and heat shield including cold shield were installed around radiator to prevent heat loss from the blackbody. Simplified mathematical model of blackbody radiator was analyzed using modified Stefan-Boltzmann's rule. The infrared radiant performance of the blackbody was evaluated using infrared camera. Based on the results of measurements, and simulation, temperature stability of the low-temperature vacuum blackbody demonstrated that the blackbody system can serve as a highly stable reference source for the calibration of an infrared optical system.

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.369-376
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• 2003

We analyzed the aspheric and/or diffractive surface effects to the performance in the long wavelength infrared (8-12 $\mu$m). Also we investigated the dependence of the NA values for the fixed effective focal length 100 mm when the field angle was varied from 5 degrees to 30 degrees stepped by 5 degrees. We chose the merit function as a criteria to compare the performance of the different lenses. Based on the analysis of the aspheric and/or diffractive surface effects, we designed the optical system of F/l.0 for the uncooled thermal imaging system. As for detector the pixel size was 45 $\mu$m square and the number of pixels were a 320${\times}$240 pixels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.4
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• pp.365-373
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• 2019

An Image Infra-Red(IIR) seeker is widely used for precision guided munitions to provide intelligent and precise target detection in terms of high kill probability. However, there have been issues in determining the performance versus cost trade-offs due to high cost of seeker comparing to other units of the munitions. In this paper, performance/cost evaluations have been carried out to find the most cost-effective solution for developing the IIR seekers. The relationships between the critical parameters and cost are investigated to determine the optimal point which represents the low cost with high performance. It is expected that the presented approach will be able to be used for guidelines to select the appropriate IIR seeker for the given operating conditions and can be useful to estimate the cost effectiveness of the precision guided munitions at early design stage.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.15-24
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• 2014

It is essential to understand the infrared signature of a naval ship to survive against various missile attacks under variable environmental conditions. As guided missiles are developing to equip more accurate IR seekers, research works for countermeasure and IR stealth technology are strongly required. But challenging works are continuously suggested for predicting and analyzing IR signal status of naval ships to achieve low observable performance under various weather conditions, variable missions and developing threats. In this study, overall guidelines of setting design criteria for low observable ships are proposed by considering varying environmental conditions including daily and seasonal variations. Test and evaluation criteria for newly constructed ships for target and background temperature difference is proposed as a design criteria which can be predicted by change of condition and ship's speed. Through the proposed techniques and procedures, it is expected to establish the measurement and evaluation criteria by using temperature, IR Signal differences between the ship and the background.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.793-798
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• 2017

In modern naval ships, an infrared signature suppression (IRSS) system is used to reduce the metal surface temperature of the heated exhaust pipe and high-temperature exhaust gases generated from the propulsion system. Generally, the IRSS systems used in Korean naval ships consist of an eductor, mixing tube, and diffuser. The diffuser reduces the temperature of the metal surface by creating an air film due to a pressure difference between the internal gas and the external air. In this study, design variables were selected by analyzing the shapes of a diffuser designed by an advanced overseas engineering company. The characteristics of the design variables that affect the performance of the IRSS were investigated through the Taguchi experimental method. A heat flow analysis technique for IRSS systems established in previous studies was used analyze the performance of the diffuser. The performance evaluation was based on the area-averaged value of the metal surface temperature and exhaust gas temperature at the outlet of the diffuser, which are directly related to the intensity of the infrared signature. The results show that the temperature of the exhaust gas was significantly affected by changes in the diameter of the diffuser outlet, and the temperature of the diffuser's metal surface was significantly affected by changes in the number of diffuser rings.

• Ecology and Resilient Infrastructure
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• v.3 no.3
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• pp.177-181
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• 2016

In order to prevent the fragmentation of animal habitat due to road construction, the most widely applied solution is building animal passes worldwide. In Korea, animal passes were introduced in the early 2000s, and through trial and error, the national guidelines for them and their design standards were published in 2010. These were criticized by politicians because of their relative inefficiency considering their high construction cost and their lack of animal usage. This study investigated the extent to which animals used the facilities. For this study, two types of animal passes, eco-bridges and ecoducts, were considered and the test sites were chosen from the Baekdu Mountains. The animal usage data was captured using infra-red CCTV cameras. The results showed that various types of animals used eco-bridges and ecoducts. Interestingly various types of birds were captured by cameras and endangered animals were also in them. The season, weather, and their surrounded vegetation also had effects on their usages. The infrared CCTV allowed detailed captures of animals but the electricity shortage was one disadvantage. During the last decades, a number of eco-bridges were constructed throughout the country and now we need to focus on their monitoring and maintenance for their successful efficiency and application.