• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.620-623
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• 2005

KARI has prepared Calibration and Validation activities for the KOMPSAT-2 (KOrea Multi-Purpose SATellite-2) MSC data that will be launched at the end of this year. Firstly, we divided the Cal/Val activities of it to four parts, Spatial, Spectral, Radiometric and Geometric, and defmed the detailed Cal/Val items from them. Secondly, Cal/Val targets have been defined and manufactured for the role of them. Thirdly, we have made the plan and the procedure for the Cal/Val items, developed the codes for them, studied more detailed method to do them, and trained the Cal/Val activities using the foreign satellite image data by ourselves. KARI has been now setting up the KOMPSAT-2 LEOP plan with the Cal/Val activities, and probably will finish the EOP Cal/Val activities for the KOMPSAT-2 MSC data by the next April or May.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.208-211
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• 2008

Band-limited filtering will be applied to remove interference resulted from two neighbored channels in the transmission of KOMPSAT-5 X-Band image data. In that case, receiver in ground station should prepare righteous matched filter to avoid huge BER degradation depending on the matched filter of COTS receiver. As an effort to simulate the bandlimited filtering, test filter was designed and manufactured on the basis of main specification for output filter of KOMPSAT-5 satellite. Consequently, 1.8dB of BER degradation was measured at the output of test band-pass filter, but the degradation was downsized up to 0.4dB thanks to the adaptive matched filter of COTS receiver.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.489-492
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• 2007

At COMS SOC, 13m antenna system will serve to transmit command and receive telemetry in S-Band for COMS operation. In addition, Sensor Data and LRIT/HRIT in L-Band will be received and LRIT/HRIT in S-Band will be transmitted through this antenna system. In many cases, G/T is used as barometer to estimate the receiving capability of antenna system. To estimate G/T, this paper presents two approaches, one is analysis based on the specification of antenna and RF equipment while the other is measurement by using Sun. From the results, G/T was proven as more than 20dB/K and it means that the required G/T, 19dB/K is verified successfully.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.482-485
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• 2007

The S-Band SSPA is front-end equipment to transmit both LRIT and HRIT to COMS. To provide the required EIRP, S-Band SSPA is designed to generate maximum 1kW power at its 1dB gain compression point (P1dB). Due to the operation for 24 hours per seven days, the verification on the performance of S-Band SSPA was performed thoroughly. This paper presents that major requirements such as maximum 1kW power, maximum -26dBc of IMD characteristic at 500W output and around -57dBc of coupling factor were verified through proposed test configuration.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.277-278
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• 2015

Korea Aerospace Research Institute(KARI) has developed the gas turbine core technologies since 1989 and has built the infrastructure for the development of gas turbine. Efficiency and flow instability are the major research object in radial and axial compressors. For combustor, NOx reduction is major research object. KARI also has developed turbine cooling technology as well as turbine aerodynamic technology.

• Journal of Aerospace System Engineering
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• v.9 no.2
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• pp.34-40
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• 2015

Staged combustion cycle engines are well known to have high combustion efficiencies and specific impulse. In this study, design of mixing head part of combustion chamber for 8tonf class staged combustion cycle rocket engine (ES-08) was performed. Structural stability of the mixing head part of the combustion chamber is very important design factor because it is loaded by high temperature and high pressure of fuel and oxidizer as well as by thrust load simultaneously. Uniformity of flow distributions of the propellants to the injectors is also important factor. First, a basic configuration for the ES-08 mixing head part was designed on the basis of the structural design requirements. And then, the structural analyses were performed on the basic configuration as well as some of reinforced configurations. As the structural analyses results, the most stable configuration was selected for the ES-08 mixing head part. In order to examine the uniformity of the flow distributions of the propellants through the manifold of the mixing head, flow analysis was performed based on the selected configuration. The results of the flow analysis showed that the fuel and the oxidizer were uniformly supplied to the injector.

• Journal of Space Technology and Applications
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• v.1 no.2
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• pp.149-159
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• 2021

This paper represents a reentry time prediction analysis of CZ-5B rocket-body in China, subject to analysis of the Inter-Agency Space Debris Coordination Committee Reentry (IADC) reentry test campaign conducted in May 2021. Predicting the reentry of space objects is difficult to accurately predict due to the lack of accurate physical information about target, and uncertainty in atmospheric density. Therefore, IADC conducts annual re-entry campaigns to verify analysis techniques by each agency, and the Korea Aerospace Research Institute has also participated in them since 2015. Ballistic coefficient estimation method proposed to predict target reentry time and the result confirmed the difference of 73 seconds, which confirms the accuracy of the proposed method.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.4
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• pp.347-356
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• 2020

In this study, Inclined Geosynchronous Orbit (IGSO) and Geostationary Orbit (GEO) of BeiDou System (BDS) and Quasi Zenith Satellite System (QZSS) satellites positions and clock errors calculated by broadcast ephemeris and compared with Multi-GNSS Experiment (MGEX) products provided by five Analysis Centers (ACs). Root Mean Square Errors (RMSE) calculated for satellite position error. The IGSO results showed that 1.82 m, 0.91 m, 1.28 m in BDS and 1.34 m 0.36 m 0.49 m in QZSS and the GEO results showed that 2.85 m, 6.34 m, 6.42 m in BDS and 0.47 m, 4.79 m, 5.82 m in QZSS in the direction of radial, along-track and cross-track respectively. RMS calculated for satellite clock error. The IGSO result showed that 2.08 ns and 1.24 ns and the GEO result showed that 1.28 ns and 1.12 ns in BDS and QZSS respectively.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.515-521
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• 2019

The C-ITS requires the lane level positioning of the vehicle in the land transportation environment, and it is most effective to utilize the global navigation satellite system. In the precision positioning system based on satellite navigation, the evaluation of dynamic environment of lane level positioning performance should be accompanied and the evaluation system configuration should be preceded. In addition, performance analysis must be performed according to various environments that change according to traffic or road conditions in a dynamic environment. In this paper, we describe with the performance of traffic and road environment through the evaluation system of lane positioning precision positioning user system based on satellite navigation system. The numerical performance evaluation was carried out based on the data collected by carrying out the actual driving. The performance evaluation by the actual driving trajectory and driving image comparison was performed to derive and analyse evaluation results of positioning performance according to driving condition.

• Journal of Astronomy and Space Sciences
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• v.27 no.4
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• pp.407-412
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• 2010

Software reusability is one of key factors which impacts cost and schedule on a software development project. It is very crucial also in satellite simulator development since there are many commercial simulator models related to satellite and dynamics. If these models can be used in another simulator platform, great deal of confidence and cost/schedule reduction would be achieved. Simulation model portability (SMP) is maintained by European Space Agency and many models compatible with SMP/simulation model interface (SMI) are available. Korea Aerospace Research Institute (KARI) is developing hardware abstraction layer (HAL) supported satellite simulator to verify on-board software of satellite. From above reasons, KARI wants to port these SMI compatible models to the HAL supported satellite simulator. To port these SMI compatible models to the HAL supported satellite simulator, simulation scheduler is preliminary designed according to the SMI standard.