• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.4
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• pp.181-186
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• 2009

This paper presents an efficient synchronizer architecture using a common autocorrelator for Digital Video Broadcasting via Satellite, Second generation (DVB-S2). To achieve the required performance under the worst channel condition and to implement the efficient H/W resource utilization of functional synchronization blocks, we propose a new efficient common autocorrelator structure. The proposed architecture can decrease about 92% of multipliers and 81% of adders compared with the direct implementation. Moreover, the proposed architecture has been thoroughly verified in XilinxTM Virtex IV and R&STM SFU (Signaling and Formatting Unit) broad-cast test equipment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.374-379
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• 2001

The satellite electronic equipment is exposed to high level random vibration environment during the launch of spacecraft. The random vibration can cause damage of electronic equipment. Thus very careful consideration on the launch environment, especially for high level random vibration, is required in the design stage of transponder equipments of communication satellite. For the structural integrity of the communication satellite transponder equipment under qualification level random vibration, Finite Element analysis was carried out using the commercial code, MSC/Nastran and ANSYS and stress levels are presented. In order to validate the femodel, modal test was also performed and compared with numerical results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.533-539
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• 2013

Number of components and payload systems installed in satellites were found to be exposed to various disturbance sources such as the reaction wheel assembly, the control moment gyro, coolers, and others. A micro-level of vibration can introduce jitter problems into an optical payload system and cause significant degradation of the image quality. Moreover, the prediction of on-orbit vibration effects on the performance of optical payloads during the development process is always important. However, analyzing interactions between subsystems and predicting the vibration level of the payloads is extremely difficult. Therefore, this paper describes the analytical and experimental approach to microvibration effects on satellite optical payload performance with integrated jitter analysis framework, micro vibration emulator and satellite structure testbed.

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.26-34
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• 2023

A high-speed data transmission system is designed for the ground inspection equipment of satellite measurement and control. Based on USB2.0, the system consists of interface chip CY7C68013A, programmable logic processing unit EP4CE30F23C8, analog/digital and digital/analog conversion units. The working principle of data transmission is analyzed, and the system software logic and hardware composition scheme are detailed. The system was utilized to output/capture and store specific data packets. The results show that the high-speed data transmission speed can reach 38MB/s, and the system is effective for satellite test requirements.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.10
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• pp.859-868
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• 2016

This paper proposes a new global positioning system (GPS) receiver algorithm to improve the positioning accuracy of a transporter using fault detection and isolation techniques from satellite signals. To improve the positioning accuracy, several factors including a feasible number of satellite signals, SNR, NAV Measurement Quality Indicator (mesQI), and Doppler, among others, have been utilized in the proposed algorithm. To increase the number of feasible satellite signals, an erroneous satellite signal has been replaced by the previous one. In conventional approaches, received GPS signals are analyzed and directly determined to be contaminated or not. The only clean signals are utilized for identifying the current location. This fault detection and isolation (FDI) feasibility test is popular for commercial GPS receivers. In the urban environment, especially near a building, the feasible number of satellite signals becomes insufficient to position the transporter. To overcome this problem, satellite signals are efficiently selected and recovered. Additionally, using the proposed GPS receiver algorithm, a feasible number of satellite signals can be increased, thereby improving the positional accuracy. Real world experiments using a transporter that carries blocks in a shipyard have demonstrated the superiority of the proposed algorithm compared to conventional approaches.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.2
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• pp.79-85
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• 2019

The mission tasks of polar exploration utilizing unmanned systems such as glacier monitoring, ecosystem research, and inland exploration have been expanded. To facilitate unmanned exploration mission tasks, precise and robust navigation systems are required. However, limitations on the utilization of satellite navigation system are present due to satellite orbital characteristics at the polar region located in a high latitude. The orbital inclination of global positioning system (GPS), which was developed to be utilized in mid-latitude sites, was designed at $55^{\circ}$. This means that as the user is located in higher latitudes, the satellite visibility and vertical precision become worse. In addition, the use of satellite-based wide-area augmentation system (SBAS) is also limited in higher latitude regions than the maximum latitude of signal reception by stationary satellites, which is $70^{\circ}$. This study proposes a local-area augmentation system that additionally utilizes Global Navigation Satellite System (GLONASS) considering satellite navigation system environment in Polar Regions. The orbital inclination of GLONASS is $64.8^{\circ}$, which is suitable in order to ensure satellite visibility in high-latitude regions. In contrast, GLONASS has different system operation elements such as configuration elements of navigation message and update cycle and has a statistically different signal error level around 4 m, which is larger than that of GPS. Thus, such system characteristics must be taken into consideration to ensure data integrity and monitor GLONASS signal fault. This study took GLONASS system characteristics and performance into consideration to improve previously developed fault detection algorithm in the local-area augmentation system based on GPS. In addition, real GNSS observation data were acquired from the receivers installed at the Antarctic King Sejong Station to analyze positioning accuracy and calculate test statistics of the fault monitors. Finally, this study analyzed the satellite visibility of GPS/GLONASS-based local-area augmentation system in Polar Regions and conducted performance evaluations through simulations.

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.45-49
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• 2003

A Bake-Out test for STSAT-1 FM(Flight Model) was performed in a Bake-Out Chamber at SITC(Satellite Integration & Test Center) in KARI(Korea Aerospace Research Institute). The purpose of this test is to measure and analyze the outgassing rate to affect the optical equipment(FIMS) and to eliminate contaminants through the high temperature bake-out. This Bake-Out test is composed of three parts which are honeycomb panels & harnesses(Batch 1), an assembled satellite(Batch 2), and a disassembled satellite(Batch 3). For each test, quantitative and qualitative measurements and analysis were performed using TQCM(Thermoelectric Quartz Crystal Microbalance) and RGA(Residual Gas Analyzer.)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.65-68
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• 2017

In this paper, a multipactor test for the space qualification model of the X-band dual-mode high-power channel filter for high-speed data transmission of geostationary satellite observation payloads was conducted and compared with the 8 dB margin required for design. It was confirmed that analytically required margins were met through testing and that satisfactory test results were obtained. The design and test of the multipactor are tested according to the ECSS standard. Based on this, it is suggested that if the margin of design is sufficiently secured, it can be used in the development of the filter for space qualification model without any test.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.554-562
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• 2004

It was recommended for all ship engaged in international voyages to carry the Satellite Emergency position Indicating Radio Beacon according to Global Maritime Distress ＆ Safety System but also it is tending to be diffused to require the satellite EPIRB installed in small vessel such as a fishery boat by domestic regulations of each countries. Otherwise the domestic regulation can't evaluate exactly the compatibility with the satellite system and the performance of the equipment itself required by international regulation. And even if it is required the performing of the performance inspection in accordance with international regulation, it is difficult to grasp the characteristics of equipment by a generalized measuring equipment. Hence this study performed the measurement for the matters related with an wave forms, modulation characteristics, frequency and the power, etc through the design and implementation of the test bench capable of ensuring most of test items regulated by international regulation. Through this study, it has been paved the way being capable of preparation of the standard regarding to transmission repetition period, phase variation and frequency stability related with the system compatibility and in conclusion, it is enable to improve the performance of a main distress communication equipment directly connected with the life of a survivor.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.1
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• pp.5-13
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• 2014

Number of components and payload systems installed in satellites were found to be exposed to various disturbance sources such as the reaction wheel assembly, the control moment gyro, coolers, and others. A micro-level of vibration can introduce jitter problems into an optical payload system and cause significant degradation of the image quality. Moreover, the prediction of on-orbit vibration effects on the performance of optical payloads during the development process is always important. However, analyzing interactions between subsystems and predicting the vibration level of the payloads is extremely difficult. Therefore, this paper describes the analytical and experimental approach to microvibration effects on satellite optical payload performance with integrated jitter analysis frame-work, microvibration emulator and satellite structure testbed.