• Journal of Convergence Society for SMB
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• v.2 no.1
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• pp.51-58
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• 2012

Android platform is a powerful operating system developed on Linux 2.6 Kernel, and provides many features such as comprehensive libraries, a multimedia environment, and powerful interface for phone applications. Since Android is an open operating system, which can be installed in any vendors's equipments. Current smartphones as well as netbooks, navigations, car PCs, tablet PCs, Industrial PCs are used in various fields. It is difficult a lot that to mount to other devices on the Android platform or new devices. In this Paper, The process that data that occurred from a hardware was passed to the highest application and Android platform system for managing hardware devices were analyzed. Building Android & driver compilation environment, How to support the protocol for the use of WiFi in the kernel, How to Mount a WiFi device in the kernel, Device driver registration for the Android platform, WiFi Management Service Daemon (wpa_supplicant) and IP allocation services daemon (dhcpcd) registration, How to create a socket for communication between the daemon (wpa_supplicant) and HAL have been presented. In the experiment using the proposed method, WiFi devices were mounted on the Android platform in the X-86 & ARM family. Understanding the whole process of control flow in Android hierarchy is very important to porting a new device on it. The process included in this paper can help technicians who might encounter the obstacles in their porting works.

• Journal of Astronomy and Space Sciences
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• v.14 no.2
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• pp.312-319
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• 1997

The magnetometer is one of the most important payloads for scientific satellite to monitor the near-earth space environment. The electromagnetic variations of the space environment can be observed with the electric and magnetic field measurements. In practice, it is well known that the measurement of magnetic fields needs less technical complexities than that of electric fields in space. Therefore the magnetometer has long been recognized as one of the basic payloads for the scientific satellites. In this paper, we discuss the scientific fluxgate magnetometer which will be on board the KITSAT-3. The main circuit design of the present magnetometer is based on that of KITSAT-1 and -2 but its facilities have been re-designed to improve the resolution to about 5nT for scientific purpose. The calibration and noise level test of this circuit have been performed at the laboratory of the Tierra Tecnica company in Japan.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.44-50
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• 2010

COMS accommodates multiple payloads; Meteorological Image(MI), Ocean Color Imager(GOCI) and Ka-band communication payloads. In order to improve the quality of MI visible channel, the moon image has been taken into account as backup reference in addition to Albedo monitoring. However, obtaining the moon image by adding special mission schedule is not recommended after IOT, because we may miss chances to obtain meteorological images during the time slots for special imaging. As an alternative solution, an approach extracting moon image from MI FD(Full Disk) image has been proposed when the moon is positioned near to the earth. However, prediction of acquisition time of moon image is somewhat difficult as the moon moves while the MI is scanning type sensor. And the moon can not be seen when it is behind the earth or outside of FD field of view. This paper discusses how effectively the moon can be detected by the MI FD imaging. For that purpose, this paper describes an approach taken to predict the time when the moon image is achievable and then introduces the results obtained from computer simulation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.8
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• pp.36-43
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• 2003

In this study, a satellite payload module was optimized by considering local stabilities. As design constraints in the satellite structure, local instabilities such as wrinkling, dimpling, crippling for honeycomb structures and crippling failure mode for beams were considered in addition to frequency and stress constraints. The constraints for the local instabilities (uncommon in general structures) were taken for the optimization of a satellite structures under severe launching environments. The analysis was performed combining the finite element analysis and optimization program. From the optimization results, it was found that frequency, crippling and wrinkling were the most critical constraints to achieve the design goals. Also, the importance of each design variable was estimated. Finally, the optimum design of the payload module was achieved for various design constraints and design parameters.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.64-74
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• 2003

This paper proposes a new autonomous stationkeeping system suitable for geostationary satellite and conducts computer simulation to verify the proposed algorithm. The proposed onboard system receives pseudo-range signal from ground equipments located at two different position with long baseline, determines the orbit error in realtime and generates orbit control commands. For minimized onboard stationkeeping logic and better reliability, the orbit controller is designed to generate control signal to have the orbit roughly follow predetermined reference range data which is generated through ground based computer simulation. The reference range data is assumed to be uploaded with time tag. A simple orbit controller is proposed which combines the reference $\Delta$V and feedback control signal. Finally, the performance of the proposed system is verified through the computer simulations.

• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.25-31
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• 2018

Captive Flight Test (CFT) is one of the most important tests to acquire data when developing complex weapon systems. In this paper, we introduce the design and test result of our POD system for CFT. POD system uses POD set which consists of left and right POD. The exterior and mass properties of POD set are equal to those of fuel tank for aircraft so that we can omit Airworthiness Certification. Also, we adequately placed inner-equipments in order to acquire data including target image, navigation result and reference data to verify and analyse software algorithm. The POD system for CFT we developed is complex system as both mechanical and electronic factors are applied. As we repeatedly performed CFT, useful and various data for weapon development were acquired.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.8-13
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• 2010

Satellite structure should be designed to accommodate and support safely the payload and equipments necessary for its own missions and to secure satellite and payloads from severe launch environments. The launch environments imposed on satellites are quasi-static accelerations, aerodynamic loads, acoustic loads and shock loads. Especially when optical payload is accommodated, satellite structure usually adopts the optical bench consisting of composite material not only to support and secure but also to guarantee good pointing stability against extreme thermal environments. This paper deals with optical bench and support structure which shall be designed to minimize the loads transferred to optical payloads from satellite.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.47.4-47.4
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• 2009

초소형전기기계시스템(MEMS: Micro-Electro-Mechanical Systems) 기술로 제작된 마이크로미러 어레이를 장착한 MEMS 우주망원경은 특유의 광시야각 감시, 목표 확인, 확대 및 고속 추적 기능을 가지며 고층대기에서의 초대형 방전현상과 같이 넓은 영역에서 드물게 임의로 일어나는 섬광현상을 관측하기에 최적이다. 러시아 과학위성 Tatiana-2의 주 탑재체로 선정된 극소형 MEMS 우주망원경 MTEL(MEMS Telescope for Extreme Lightning)은 광시야각 감시와 목표 확인을 위한 트리거망원경, 목표 확대와 고속추적을 위한 확대망원경 및 섬광현상의 분광측정을 위한 분광계로 구성되어 있다. 1년간의 개발 및 성능 검증 후 MTEL은 위성탑재를 위한 모든 우주인증 시험을 성공적으로 마쳤다. 현재 MTEL은 Tatiana-2 위성에 탑재되어 있으며, 9월 18일에 우주로 발사되어 1-3년간 800km 궤도를 비행하며 지구 대기에서 발생하는 섬광현상을 관측할 예정이다. 이 발표에서는 MTEL 탑재체의 설계, 제작, 성능 측정 및 calibration 결과를 보고하고, 위성탑재를 위한 진동 및 충격, 열, 진공 및 전자기파 적합성 등의 우주인증 시험 결과 또한 보고한다. 또한 발사 후 과학위성 및 MTEL의 이 발표 때까지의 우주에서의 상황을 보고한다.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.127-133
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• 2014

In this paper, we present the design, functions and performance analysis of the virtual machine (VM) based on the Lua interpreter for On-Board Control Procedure Execution Environment (OEE). The development of the OEE has been required in order to operate the lunar explorer mission autonomously which is planned by Korea Aerospace Research Institute (KARI) autonomously. The concept of On-Board Control Procedure (OBCP) is already being applied to the deep space missions with a long propagation delay and a limited data transmission capacity since it ensure he autonomy of the mission without the ground intervention. The interpreter is the execution engine in the VM and it interpreters high-level programming codes line by line and executes the VM instructions. So the execution speed is very more slower than that of natively compiled codes. In order to overcome it, we design and implement OEE using register-based Lua interpreter for execution engine in OEE. We present experimental results on a range of additional hardware configurations such as usages of cache and floating point unit. We expect those to utilized to the OBCP scheduling policy and the system with Lua interpreter.

• Journal of Broadcast Engineering
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• v.24 no.1
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• pp.105-117
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• 2019

Current Android smartphones include about 25 to 35 essential applications(unerasable) related to function and operation of the android smartphone itself and about 30 optional applications(removable) provided by carriers, Google and manufacturers. These applications were not able to be removed until the announcement of the smartphone applications pre-install guide from the government in January 2014, so there were memory limitations in installing new applications, causing consumer complaints by consuming data during the auto-update process of the pre-installed applications. After the announcement, we were able to delete optional applications but the complaints about the data consumption still did not disappear. Therefore, in this paper, we carried out the customer survey and analyzed the behavior information such as how carriers are operating pre-installed applications and what kind of applications customer prefers and how many applications customer wants to be pre-installed. And we proposed how to configure pre-install applications on smartphone for customer needs.