• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.419-422
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• 2006

위성발사체와 같이 극환 환경에서 사용되는 전자 탑재물들은 진동이나 충격이 가해질 때 정상적으로 동작하지 못하는 경우가 많다. 그러므로 위성발사체에 탑재되는 모든 탑재물들은 발사전에 지상에서 다양한 환경시험을 통하여 그 성능을 검증해야 한다. 기준 클럭을 사용하여 항법해를 계산해야 하는 GPS 수신기는 특히 다른 전자 탑재물 보다 클럭의 안정도에 더 많은 영향을 받으므로 극한 진동 및 충격 환경에서 다양한 문제들이 나타난다. 본 논문에서는 위성발사체의 비행안전용으로 개발된 GPS 수신기의 진동 및 충격 환경시험 결과를 바탕으로 그러한 환경에서 기준 클럭이 영향을 받아 나타나는 다양한 동작특성을 설명하고, 기준 클럭의 중요성과 진동 및 충격 환경시험에서의 유의사항 및 문제 해결 방법에 대하여 설명한다.

• Review of KIISC
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• v.31 no.1
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• pp.15-23
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• 2021

자율주행 시스템이 탑재되어 있는 무인이동체는 운용환경에 따라 공중, 해상, 육상 무인이동체로 분류할 수 있고 모든 분야에서 관련 기술 개발이 활발히 진행되고 있다. 무인이동체는 자율주행 시스템이 탑재되어 외부 환경을 스스로 인식해 상황을 판단하는 특징을 갖고 있다. 따라서, 무인이동체는 센서로부터 수집되는 데이터를 이용하여 주변 환경을 인식해야 한다. 이러한 이유로 보안 (Security) 분야에서는 무인이동체에 탑재되는 센서를 대상으로 신호 오류주입을 수행하여 해당 무인이동체의 오동작을 유발하는 연구결과들이 최근 발표되고 있다. 신호 오류주입공격은 물리레벨 (PHY-level) 에서 수행되기 때문에, 공격 수행 여부를 소프트웨어 레벨에서 탐지하는 것은 매우 어렵다는 특징을 갖고 있다. 현재까지 신호 오류주입 공격을 탐지할 수 있는 방법은 다수의 센서를 이용하는 센서퓨전 (Sensor Fusion)을 기반으로 하는 방법이 있다. 하지만, 현실적으로 하나의 무인이동체에 동일한 기능을 하는 센서 여러 개를 중복해서 탑재하는 것은 어려움이 있다. 그리고 단일 센서만을 이용하여 신호 오류주입 공격을 탐지하는 방법에 대해서는 아직까지 연구가 진행되고 있지 않다. 본 논문에서는 무인이동체 환경에서 가장 널리 사용되고 있는 MEMS 센서를 대상으로 신호 오류주입 공격을 재연하고, 단일 센서 환경에서 해당 공격을 탐지할 수 있는 방법에 대하여 제안한다.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.46.1-46.1
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• 2019

우리나라 최초의 우주탐사 사업인 달 탐사선(KPLO) 개발 사업에는 국내에서 개발하는 과학 탑재체 3기, 기술 검증탑재체 1기, 고해상도 카메라 1기, 국제협력의 일환으로 NASA의 과학 탑재체 1기도 함께 개발되고 있다. KPLO와 이들 탑재체의 운영을 수행하게 될 KPLO 심우주 지상시스템은 달 탐사선 운영에 필요한 궤도, 임무계획 등의 정보를 생성하고, KPLO의 기동명령과 상태정보를 송, 수신하는 역할을 주요 임무로 수행한다. 또한 이들 정보를 기반으로 궤도임무를 수행하고 있는 KPLO의 임무운영 상태를 시각화하여 운영자로 하여금 KPLO 운영을 용이하게 하고, 공공에게 이를 제공하는 역할도 함께 수행한다. KPLO 심우주 지상시스템은 AGI사의 STK와 NASA/JPL에서 개발한 Cosmographia를 활용하여 각각 특성에 맞는 KPLO 운영 시각화 정보를 제공할 것이다. 본 발표에서는 Cosmographia의 작동 및 활용 개념을 설명하고, KPLO의 가상 임무를 적용한 SPICE Kernels을 활용하여 고해상도 카메라인 LUTI의 지향, 달 중심 표준좌표를 적용한 KPLO의 궤도 등을 시각화 시연을 한다. 또한 고해상도 달 표면 영상 적용, 심우주 네트워크 안테나의 위치 정보표출 등 Cosmographia에서 기본적으로 제공하던 시각화 정보를 개선한 내용에 대해서도 함께 시연한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1999.10a
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• pp.73-73
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• 1999

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.10
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• pp.910-915
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• 2012

In this paper, the loading methods of EOTS for an exploratory developing fighter were analysed by the technical characteristics of it's operation, maintenance, engineering technology and development cost. By the analysis of operational ability evaluation, the internal type had the merits of stealth function, but the external loading type was preferable to certificate the accessibility, install/detach, compatibility and interoperability with the existing fighter aircraft. From the results of 17 items of technology and development cost evaluation, we found out that the internal type had the advantage of small sizing lightweight, but the external type was highly estimated in the field of application of domestic technology, cost reduction and technical stability for achievement of performance.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.104-109
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• 2016

A technology of GEO satellite communications starts from Koreasat program in Korea. Payload equipment of EQM Ku and Ka band transponders had been developed and space-qualified Ka band payload in COMS was successfully launched in June, 2010. For the purpose of military communications, Dehop-Rehop transponder was developed in Koreasat5 as ANASIS system and DAT(Digital Active Transponder) and DCAMP(Digital Channel AMPlifier) transponders are now under development. In this paper, from the study of military satellite communications trend, a direction of military communication satellite is suggested based on the current GEO SATCOM technologies in Korea. Considering the limit of frequency resources, a technology of battlefield adaptive transponder with medium capacity against high moveable jamming tactics would be efficient for the future military SATCOM system. Mid-sized military satellites with frequency hopping and mid-capacity transponders can be a solution of vitalizing the GEO satellite programs.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.9
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• pp.897-904
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• 2017

Optical equipment consists of various components, and a detector is mounted and operated on aircraft, tanks, and warships for target detection and classification. The structural stability and optical performance of aeronautical optical equipment operated at several kilometers of altitude are degraded owing to vibration generated in the aircraft. It is necessary to verify the structural stability and optical performance requirements of the equipment in vibration environment conditions during the design phase. In this study, vibration environment conditions were analyzed using a test standard and the measurements of the vibration generated in aircraft. The conditions were classified as endurance and operating vibration conditions for structural stability and optical performance verification, respectively. The structural stability was verified according to natural frequency analysis, response analysis for the endurance vibration condition, and static analysis. The optical performance was verified by applying the vibration response analysis results to the optical design/analysis program.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2223-2231
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• 2010

Recently, an important physical device of transportation, such as car, railroad, ship and aircraft has changed into electronic control unit. According to accident reports, the most of car accidents are caused by faults of embedded software loaded to computer control unit. The facts implies that the test to find defects in embedded software haven't performed sufficiently. As a result, it is necessary to establish the test procedures of embedded software based on safety assessment criteria. The objective of this proposal is to provide a unit test procedure complied with the safety assessment criteria for the embedded software. In addition, an effective unit testing procedure and defect analysis methods are proposed and a testing procedure using a safety criteria built-in tool is presented.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.1-7
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• 2010

For many years the development and verification of on-board flight software have been essentially performed on STB (Software Test Bed) environments which consist of real hardware in KARI. During development of on-board flight software on STB, we experienced many difficulties such as the late delivery of target hardware and limitation to access STB simultaneously by multiple developers. And it takes too much time and cost to build up multiple STBs. In order to successfully resolve this kind of problems, the software-based spacecraft simulator has been developed. The simulator emulates the on-board computer, I/O modules and power controller units and it supports the debugging and test facilities to software engineers for developing flight software. Also the flight software can be loaded without any modification and can be executed as pseudo real-time. This paper presents the architecture and design of software-based spacecraft simulator, and flight software development and verification under this environment.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.177-187
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• 2002

Some kinds of precision optical systems for spaceborne high resolution cameras were designed at preliminary design level and an optical design for a hyperspectral imager was performed for its development model. A Cassegrain-based catadioptric system and an unobscured reflective triplet system are illustrated in detail for spaceborne high resolution electro optical cameras which have performance of 5m resolution at an altitude of 685km and the design are evaluated in its spot-diagram and MTF to prove they have good performance enough to implement the requirements for realistic satellite payload taking the fabrication conditions and the on-orbit operation into consideration. For the development of hyperspectral imager as a next-generation payload, an optical system has been designed and elaborated. It can be divided into two parts, a catoptric telescope forming an off-axis 2 mirror type and a dispersive spectrometer which comprises collimator, grating and reimaging lens cell. From its optical design to the system characteristics are shown with the MTF performance reaching 25% approximately.