• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.133-139
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• 2003

Position and trajectory data in-flight rocket are important informations to determine flight safety of rocket. In general tracking system, radar and transponder are used to acquire position information. Rocket position and trajectory can be determined by RF communication between ground station and in-flight rocket, and antenna position date. In this paper, it explains the ranging system which is low resolution rather than radar system but system configuration is simple. Therefore this system is useful for experimental flight vehicle.

• Aerospace Engineering and Technology
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• v.11 no.2
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• pp.164-170
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• 2012

This paper presents that the comparison results of AT (Active Transponder) positions obtained from different measurements: the result of GPS device and evaluated position from the SAR (Synthetic Aperture Radar) image, and active transponders can be useful as GCPs(Ground Control Points) in SAR images. The X-band AT are installed on the wide-and-flat area to improve SCR(signal-to-clutter ration), and activated to represent impulse response function in order to operate as one point target in SAR images. Cosmo-SkyMed operating at X-band frequency are used to provide SAR images of AT. The comparison of AT position is performed by using the result of GPS device field measurement and AT SAR images. ENVI-SARscape S/W is used to evaluate AT position in the SAR images. From the comparison, it is shown that AT are useful as GCPs for SAR images.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.437-442
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• 2021

This study describes the design and implementation of power supply of dehop/rehop transponder of EQM(Engineering Qualification Model). We materialized the interface of the PLDIU and power supply of a satellite bus, and minimized the potential for the occurrence of such erroneous operation circuit ESD through the WCA of the space environment. We designed a reliable power supply through simulation for TID about space radiation and simulation of the vibration generated during it launched, and we confirmed that it satisfies the environmental test specification through the test space environment after production.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.332-336
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• 2004

This paper describes the remote tracking algorithm using measurements (azimuth, elevation, and slant range) of the radar ground station. Kalman filter model for noise reduction of the measured information is first derived by linearizing with respect to angle, angular rate, range, and range rate. And then a tracking algorithm is introduced to calculate the position of the vehicle during in-flight. The simulation results show that the algorithm is practical and effective enough tracking position of the vehicle in considerably less error.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.6
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• pp.507-513
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• 2002

In this paper, the receiver using Heterodyne type is designed and implemented for a pulse radar at 9.4 GHz. The If amplifier, which occupies a significant size in a Heterodyne receiver for pulse radars, can be removed. Furthermore, by using detector logarithmic video amplifier in baseband, the receiver has a small size and it's characteristic shows a high dynamic range and sensitivity. From the results of measurements, the minimum receiver power of -70 dBm and selectivity of 55 dB are obtained.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.1
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• pp.72-78
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• 2015

Recently, the usage of the satellite is increased more and more in the areas that are communication, weather, marine, optical, radar etc. The functions of the Satellite are evolving from passive transponder to active transponder by the developing of a technology. Advanced countries in satellites install the DCAMP for increase of bandwidth efficiency, improvement of QoS by interference rejection. DCAMP includes many digital components in order to implement functions. Thus, these kinds of active transponders consume much more power compared to passive transponder and then increase the heat. In this paper, we discuss the TVAC test result of DCAMP in EQM(Engineering Qualification Model) level. The paper shows the test results of digital gain control in order to verify DCAMP status under the TVAC test. In addition, the temperature and heat condition of main components from viewpoint of derating will be treated through the official environment test for qualification.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.773-779
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• 2022

Deep-sea fisheries in Korea play an essential role in supplying popular seafood and providing food security. Countries, as well as the IMO (International Maritime Organization), have attempted to establish an internationally harmonized safety standard for fishing vessels. However, starting with the adoption of 'The Torremolinos International Convention for the Safety of Fishing Vessel 1977', the '2012 Cape Town Agreement' was adopted, but the requirements for enforcement were not met. However, with the 2019 Torremolinos Declaration, the effect of the agreement became visible. Korea is also about to ratify the agreement, and deep-sea fishing vessels are subject to the agreement. The length of the hull or the gross tonnage can be selected as the criteria for applying the 2012 Cape Town Agreement, and this is also partially applied to the existing vessels. Analyzing 188 deep-sea fishing vessels registered as members of the Korea Overseas Fisheries Association to confirm the effect on the existing vessels showed that the application of gross tonnage had little impact on the ratification of the agreement. In addition, laws must be revised for the compulsorization of GMDSS facilities such as two-way VHF and radar transponders and for the safety familiarization of fishermen. In the industry, the facilities required by the agreement must be provided, and the fishermen must be familiarized with safety.