• 한국항공우주학회지
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• 제44권8호
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• pp.702-709
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• 2016

우리나라의 위성개발이 본격적으로 착수된 이래 개발자들의 노력으로 국내독자개발 역량을 확보하였다. 지난 20년 동안 실용급 원격탐사위성의 경우 세계적인 수준에 도달하였으며 정지궤도위성은 임무에 따라 국내주도로 개발할 수 있는 기술력을 구축하였다. 세계 시장의 진출을 위한 표준본체 기반의 차세대중형위성 개발을 진행하고 있으며 금년부터는 달탐사 궤도선 개발에 착수하였다.

• 한국군사과학기술학회지
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• 제22권5호
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• pp.616-624
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• 2019

In order to understand flying aircraft, satellite, missile, etc, a telemetry ground system is used to receive, record, and process the transmitted radio signal from vehicles. In some cases, a line-of-sight communication is not possible along to the trajectory of vehicles, and multipath fading result in a shade area of communication. A number of telemetry ground systems are installed to overcome this limitation, and acquire the transmitted signal seamlessly. The telemetry signals received by multiple independent ground systems have independent probability of errors since they experienced their own communication channels. In other words, we can exploit the independent error characteristics of received signals by processing them in a hybrid method. The optimum hybrid post-process method is proposed in this study, and applied to process telemetry signals acquired from flight tests.

• 농촌지도와개발
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• 제10권2호
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• pp.229-237
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• 2003

Since the 1960s in Korea, major broadcasting channels broadcasted farm television programs, however, airing of these programs were reduced in the 1990s. This was due to the declining number of farmers, and the low popularity rating of farm television programs. To cope with the situation, agriculture businessmen, farmers, and the officials concerned tried to acquire the independent farming television channel in cable television and satellite television, In 1998, one cable television channel started broadcasting, while another channel in satellite television began its broadcasting in 2001. One of the major concerns of the people in the broadcasting was actualization of the public interests in the new media multi-channel age. Recognizing this point, the study explored a few areas of concern such as conceptualizations of the public interest of the people in the digital age, examination of the surroundings of program production and marketing, and survey the media use behavior of target audience - rural residents; In the concept of the public interest, there are two points of view; market focused and democratic principle oriented. As the digitalization of broadcast advances and the logic of economics prevails, it is difficult to offer the public broadcasting service to farmers, however, democratic principles should be more emphasized. The rural resident prefer major terrestrial television channel to cable television and satellite television channel, and in media use behavior, the medium of major terrestrial television would be more useful for farm broadcasting.

• 한국위성정보통신학회논문지
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• 제12권4호
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• pp.56-61
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• 2017

최근 우리나라 위성 개발 사업은 과거와 달리 다양한 목적에 따라 수요 중심으로 변화하고 있다. 특히, 단순 지상 영상 관측 위성에서 벗어나 위성 자료를 가공, 고부가가치 정보 생산에 대한 중요성이 제시되고 있다. 이러한 추세에 따라 위성 정보에 대한 수요 확대를 위해 최종 수요 대상인 국민들의 요구 사항을 반영한 맞춤형 개발과 정보 제공이 필요한 시점이다. 이에, 본 연구에서는 환경위성의 국민 맞춤형 서비스를 위해 요구사항 분석을 위해 대학생을 중심으로 설문 조사를 시행하고 그 결과를 분석하였다. 그 결과, 환경위성은 발사, 운영 전임에 따라 인지가 부족한 상황이나, 최근 환경이슈인 미세먼지에 대한 인지가 높아 활용의지는 높은 것으로 파악되었다. 또한, 환경안보에 대한 의지가 높아 독자적인 환경위성 개발의 필요성을 인지하고 있으며, 언론 등을 통한 홍보와 접근이 용이한 매체를 통한 자료 제공을 선호하는 것으로 나타났다.

• 대한원격탐사학회지
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• 제38권6_4호
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• pp.1955-1969
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• 2022

KOMPSAT 시리즈 등 국가 위성정보를 활용하는 공공 및 민간의 사용자들은 대부분 광학 영상 중심으로 위성영상을 활용하고 있으며, 상대적으로 Synthetic Aperture Radar (SAR) 영상의 활용은 미흡한 실정이다. 현재 운영 중에 있는 KOMPSAT-5를 비롯하여 향후 KOMPSAT-6 및 초소형 SAR 위성체계 등이 발사 예정에 있기 때문에 다양한 분야에서 SAR 위성정보의 활용요구가 증대되고 있다. 이에 따라 SAR 위성정보 활용을 지원할 수 있는 SAR 활용 핵심 기술 보유가 필요한 시점이다. SAR 특성을 활용한 핵심 활용 기술로 변화탐지 기술이 있지만 현재까지도 SAR 영상을 활용하여 자동으로 변화를 탐지하고 사용자에게 알림하는 기술 개발은 요원한 상태이다. 본 연구는 독자적인 SAR 자동변화탐지알림 기술을 확보하고 우리나라 위성정보활용협의체와 같은 공공분야 기관의 실무자가 실무에 국내 SAR 위성정보를 활용하는 것을 촉진하기 위해 다중시기 KOMPSAT-5 SAR 위성영상의 자동변화탐지알림 기능 요소를 도출하고 프로토타입 프로그램을 개발하였다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 추계학술발표회 논문집
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• pp.269-274
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• 2004

Recent adoption of the generalized sensor model to IKONOS and Quickbird satellite imagery have promoted various research activities concerning alternative sensor models which can replace conventional physical sensor models. For example, there are the Rational Function Model(RFM), the Direct Linear Transform(DLT) and the polynomial transform. In this paper, the DLT model which uses just a few number of GCPs was suggested. To evaluate the accuracy of the proposed DLT model, the RFM using 35 GCPs and the bias compensation method(Fraser et al., 2003) were compared with it. Quantitative evaluation of 3B positioning results were performed with independent check points and the digital elevation models(DEMs). In result, a 1.9- to 2.2-m positioning accuracy was achieved for modeling and DEM accuracy is similar to the accuracy of the other model methods.

• 농촌지도와개발
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• 제23권3호
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• pp.285-293
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• 2016

The increase in demand for leisure time by the public and the vitalization of agricultural tourism resulting from the expansion of the five-day work week are expected to greatly contribute to the rural economy, but actual studies analyzing the ripple effect of the agricultural tourism industry are lacking. In order to analyze the economic ripple effect, tourism or agricultural tourism must become an independent sector in the inter-industry relations table's sector classification, but because it is not, the study uses a method of analysis which involves creating a satellite account. However, because agricultural tourism has a clear main agent in farms unlike general tourism which does not, there is one method in which provisions are made by farms or farm villages and another method in which outside products are used. The purpose of the present is to measure the economic ripple effect of agricultural tourism with a focus on 162 subclasses by applying positive data from the education sector input into agricultural tourism. Satellite accounts which considered intermediate input were created and applied to positive data, the analysis of which revealed agricultural tourism to account for 462 billion won, which is 0.01% of the total production amount of 3,503,480 billion won, while the production inducement coefficient was 3.2895 units when the final demand of agricultural tourism occurs. When the production inducement coefficient is at 3.2895 units, highest sector was agricultural tourism at 0.9968 units followed by restaurants and bars at 0.3325 units, roadt transportation services at 0.3183 units, lodging services at 0.1520 units, and petroleum products at 0.1290 units.

• Journal of Positioning, Navigation, and Timing
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• 제12권4호
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• pp.359-367
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• 2023

In order to ensure the high-integrity of reference stations of satellite navigation system, cycle slip should be precisely monitored and compensated. In this paper, we proposed a cycle slip algorithm for the integrity monitoring of the reference stations. Unlike the legacy method using the Melbourne-Wübbena (MW) combination and ionosphere combination, the proposed algorithm is based on ionosphere combination only, which uses high precision carrier phase observations without pseudorange observations. Two independent and complementary ionosphere combinations, Ionospheric Negative (IN) and Ionospheric Positive (IP), were adopted to avoid insensitive cycle slip pairs. In addition, a second-order time difference was applied to the IN and IP combinations to minimize the influence of ionospheric and tropospheric delay even under severe atmosphere conditions. Then, the cycle slip was detected by the thresholds determined based on error propagation rules, and the cycle slip was identified through weighted least square method. The performance of the proposed cycle slip algorithm was validated with the 1 Hz dual-frequency carrier phase data collected under the difference levels of ionospheric activities. For this experiment, 15 insensitive cycle slip pairs were intentionally inserted into the raw carrier phase observations, which is difficult to be detected with the traditional cycle slip approach. The results indicate that the proposed approach can successfully detect and compensate all of the inserted cycle slip pairs regardless of ionospheric activity. As a consequence, the proposed cycle slip algorithm is confirmed to be suitable for the reference station where real time high-integrity monitoring is crucial.

• Journal of Positioning, Navigation, and Timing
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• 제6권3호
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• pp.125-133
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• 2017

Time comparison is necessary for the verification and synchronization of the clock. Two-way satellite time and frequency (TWSTFT) is a method for time comparison over long distances. This method includes errors such as atmospheric effects, satellite motion, and environmental conditions. Ionospheric delay is one of the significant time comparison error in case of the carrier-phase TWSTFT (TWCP). Global Ionosphere Map (GIM) from Center for Orbit Determination in Europe (CODE) is used to compare with Bernese. Thin shell model of the ionosphere is used for the calculation of the Ionosphere Pierce Point (IPP) between stations and a GEO satellite. Korea Research Institute of Standards and Science (KRISS) and Koganei (KGNI) stations are used, and the analysis is conducted at 29 January 2017. Vertical Total Electron Content (VTEC) which is generated by Bernese at the latitude and longitude of the receiver by processing a Receiver Independent Exchange (RINEX) observation file that is generated from the receiver has demonstrated adequacy by showing similar variation trends with the CODE GIM. Bernese also has showed the capability to produce high resolution IONosphere map EXchange (IONEX) data compared to the CODE GIM. At each station IPP, VTEC difference in two stations showed absolute maximum 3.3 and 2.3 Total Electron Content Unit (TECU) in Bernese and GIM, respectively. The ionospheric delay of the TWCP has showed maximum 5.69 and 2.54 ps from Bernese and CODE GIM, respectively. Bernese could correct up to 6.29 ps in ionospheric delay rather than using CODE GIM. The peak-to-peak value of the ionospheric delay for TWCP in Bernese is about 10 ps, and this has to be eliminated to get high precision TWCP results. The $10^{-16}$ level uncertainty of atomic clock corresponds to 10 ps for 1 day averaging time, so time synchronization performance needs less than 10 ps. Current time synchronization of a satellite and ground station is about 2 ns level, but the smaller required performance, like less than 1 ns, the better. In this perspective, since the ionospheric delay could exceed over 100 ps in a long baseline different from this short baseline case, the elimination of the ionospheric delay is thought to be important for more high precision time synchronization of a satellite and ground station. This paper showed detailed method how to eliminate ionospheric delay for TWCP, and a specific case is applied by using this technique. Anyone could apply this method to establish high precision TWCP capability, and it is possible to use other software such as GIPSYOASIS and GPSTk. This TWCP could be applied in the high precision atomic clocks and used in the ground stations of the future domestic satellite navigation system.

• 대한원격탐사학회지
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• 제28권3호
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• pp.319-327
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• 2012

In this paper, we introduce a newly developed photogrammetric software for automatic generation of high quality geo-products and its performance assessment carried out using various satellite images. Our newly developed software provides the latest techniques of an optimized sensor modelling, ortho-image generation and automated Digital Elevation Model (DEM) generation for diverse remote sensing images. In particular, images from dual- and multi-sensor images can be integrated for 3D mapping. This can be a novel innovation toward a wider applicability of remote sensing data, since 3D mapping has been limited within only single-sensor so far. We used Kompsat-2, Ikonos, QuickBird, Spot-5 high resolution satellite images to test an accuracy of 3D points and ortho-image generated by the software. Outputs were assessed by comparing reliable reference data. From various sensor combinations 3D mapping were implemented and their accuracy was evaluated using independent check points. Model accuracy of 1~2 pixels or better was achieved regardless of sensor combination type. The high resolution ortho-image results are consistent with the reference map on a scale of 1:5,000 after being rectified by the software and an accuracy of 1~2 pixels could be achieved through quantitative assessment. The developed software offers efficient critical geo-processing modules of various remote sensing images and it is expected that the software can be widely used to meet the demand on the high-quality geo products.