• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.412-417
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• 2022

In this paper, multi-GNSS network RTK MAC correction generation software developed based on MATLAB GUI is introduced. The software was developed as a post-processing software based on simulation data to evaluate the feasibility of an algorithm for generating correction for multi-GNSS including GPS, GLONASS, and Galileo. As a result of software operation, network RTK correction for each system of multi-GNSS is output in MATLAB file format. In this paper, to evaluate the performance of the developed software, the residual error was analyzed after applying the correction generated through the software to the user. As a result of the analysis, it was confirmed that effective network RTK correction could be generated by confirming that the residual errors of users were maintained at 10 cm or less.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.2
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• pp.125-138
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• 2020

One of the most important steps to consider in utilizing micro-satellites for surveillance or reconnaissance operations is the design of the satellite constellation. The Walker-Delta constellation which is commonly used in designing satellite constellations is not ideal for this operation in which military satellites are required to monitor specific regions continuously in a stable manner. This study aims to discuss the methodology for designing a satellite constellation that is capable of monitoring the fixed region at the fixed time each day by using the Sun synchronous Orbit. The BB(Beach Ball) constellation that we propose outperforms the Walker-Delta constellation in terms of robustness and it holds the merit of being simple in its design, thereby making future expansions more convenient. We expect the BB constellation will have a high applicability as the operational concept of military surveillance satellites is established in the near future.

• Journal of Aerospace System Engineering
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• v.16 no.2
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• pp.63-72
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• 2022

As interest in microsatellites increases, research has been actively conducted recently on the performance and use, as well as the orbital design and deployment techniques, for the microsatellite constellations. The purpose of this study was to investigate orbital deployment techniques using thrust and differential atmospheric drag control (DADC) for the Walker-delta constellation. When using thrust, the time and thrust required for orbital deployment vary, depending on the separation speed and direction of the satellite with respect to the launch vehicle. A control strategy to complete the orbital deployment with limited performance of the propulsion system is suggested and it was analyzed. As a result, the relationship between the deployment period and the total thrust consumption was derived. It takes a relatively longer deployment time using differential air drag rather than consuming thrusts. It was verified that the satellites can be deployed only with differential air drag at a general orbit of a microsatellite constellation. The conclusion of this study suggests that the deployment strategy in this paper can be used for the microsatellite constellation.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1992.06a
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• pp.635-640
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• 1992

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.417-424
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• 2016

Russia recently began broadcasting the SDCM signal in order to provide SBAS service for the civil aviation in the Russian territory using its own geostationary satellites. The service coverage of the SDCM geostationary satellite, LUCH-5A and LUCH-5B, includes Korea peninsula, where the test signal from the pseudo random number (PRN) 140 is received. This paper shows that the position accuracy at the Chulwon GNSS site is improved to 0.8749 m (horizontal) and 0.9589 mm (vertical) by applying the received SDCM message to the RINEX data. Considering that the SDCM augments both GPS and GLONASS, the performance of multi-constellation SBAS was compared to that of GPS-only SBAS, and APV-I availability was improved by decreasing the protection level about 30 %. From the results, we can expect that the mult-constellation SBAS can contribute to the performance enhancement of the future KASS.

• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.213-219
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• 2017

Large satellite development programs might take decades to build, launch and operate in space environments at costs in excess of a billion dollars. However, small satellites can reduce the costs not only by using commercial software and sensors, but also by shortening the development period to two years or less. In this paper, we discuss the development status of small satellites, and propose some military applications of small satellites. First, we describe the industrial trends of small satellites in advanced countries such as the United States and Japan. Also, we describe the development status of small satellites in Korea. Military applications are largely classified into education, research, and operational purposes. Small satellites are developing rapidly in commercial markets and they will play an important role in military sector. Therefore, the military should consider small satellites as important strategic assets in future conflicts and provide means to develop them.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.4
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• pp.600-610
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• 2001

The effects of group delay and non-linear characteristics on high data rate(HDR) satellite channel are presented in this paper Based on the modeling of group delay and non-linear characteristics the system performances which provide various data rate services were analyzed in Ka-band satellite channel. As the transmission data rate is increased, the degradation due to these channel characteristics is severely increased. The linear component of group delay and the AM-AM component of non-linear characteristics severely affect the system performance. To efficiently provide the various service via the same transmission system it is necessary to equalize the primary impairment factors. The optimum operating points of HDR satellite transmission system are implemented by considering the analyzed results on channel characteristics.

• Defense and Technology
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• no.5 s.255
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• pp.48-57
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• 2000

새천년이 시작되는 21세기는 정보산업의 시대이고, 우리 군의 미래전력도 정보획득능력에 의해 결정될 것임은 부인할 수 없는 사실이다. 이제, 인공위성 이야기는 더 이상 우리의 머리위를 떠돌아 다니는 "남의 별"들의 이야기가 아닌, "우리 별"의 이야기여야 한다. 미국이나 프랑스를 중심으로 하는 위성 선진국들이 엄청난 규모의 위성시장을 놓고 눈에 보이지 않는 전쟁을 하고 있는 이 시기에, 2000년대를 맞이한 우리의 과제가 무엇인지는 명확해진다.

• Defense and Technology
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• no.6 s.292
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• pp.28-35
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• 2003

현재 우리나라는 군사적 용도의 우주전력은 전무한 실정이나, 군사차원에서 1992년 최초롤 우리별 1호를 발사한 이후 꾸준히 연구 개발을 해온 결과 현재는 세계에서 23번째 실용 위성 보유국이 되었으며, 2015까지 세계 10위권 위성보유국 대열에 진입하기 위한 국가 우주개발 중장기 계획을 수립하여 적극적으로 추진해 나가고 있다. 따라서 군에서도 주변국의 우주개발에 대한 경쟁에 뒤지지 않고 21섹이의 한반도 주변 전략환경을 우리에게 유리하게 진행시키기 위해서는 무엇보다도 우주의 군사력 활용이 필요하며 우주전력을 이용한 작전능력의 신장, 우주전력의 지원, 우주전투 능력 확보를 위한 장기적인 우주계획을 수립하는 등 군 우주분야의 발전이 절실히 요구되고 있다.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.121-126
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• 2014

ETRI(Electronics and Telecommunication Research Institute) has joined National GNSS Research Center program of Defense Acquisition Program Administration and Agency for Defense Development in 2010. The research subject is technology for MSAR(Military Search and Rescue) system configuration. In this project, we analyses the ways in order to improve the accuracy, reliability, availability for MSAR system from M&S(Modeling and Simulation). The MSAR System M&S Software can be used for performance analysis of new elements, such as ground elements and satellite elements without any hardware development. In this paper, after introduction of the architecture design and functional scope of the simulator, the performance analysis result for MSAR M&S software is presented.