• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2018.11a
• /
• pp.114-116
• /
• 2018

본 논문에서는 빔-호핑 위성 전송 시스템을 위한 카운터를 기반의 연속적인 beam allocation time schedule (BATS) 변경 기법을 제안한다. 제안하는 기법은 BATS 를 처음 변경할 때, 카운터를 기반으로 gateway (GW)와 space craft (SC) 양단에서 BATS 변경 시점을 동기화 시킨다. 이 후, BATS를 계속 변경하더라도 전송 데이터 손실 없이 BATS 를 변경할 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2018.06a
• /
• pp.264-266
• /
• 2018

본 논문에서는 빔-호핑 위성 전송 시스템을 운용하기 위해 필수적으로 이루어져야 하는 빔 스위칭 타임 플랜 (Beam Switching Time Plan, BSTP) 동기 기법을 제안한다. 제안하는 기법은 게이트웨이의 변조 모듈에서 SF (super-frame) 신호를 전송한 후, 레퍼런스 수신 모듈에서 신호 전송 후 프레임 검출이 일어나기까지 걸리는 시간과 유효한 신호 검출 후 프레임 검출이 일어나기까지 걸리는 시간을 이용하여 BSTP 동기를 이룬다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2020.11a
• /
• pp.15-17
• /
• 2020

본 논문에서는 Convolutional Neural Network(CNN)를 이용한 위성 영상 변화탐지 알고리즘을 제안한다. 우선 EfficientNet 기반의 대칭 인코더-디코더 구조의 변화탐지 네트워크를 구성한다. 그리고 디코더 단에 ASPP 모듈을 추가하여 넓은 수용영역을 갖는 특징 정보를 통해 변화지도(change map)를 복원한다. 실험 결과를 통해 검출 성능 및 연산 효율성이 기존 기법보다 우수함을 보인다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.04a
• /
• pp.385-387
• /
• 2000

디지털 기술 및 통신 기술의 발달로 방송.통신.컴퓨터.가전의 경계가 불확실해지고 사용자에게 다양한 형태의 융합된 서비스 제공이 가능하게 되어, 일방적으로 서비스를 사용자에게 제공하는데 그치지 않고 사용자가 서비스를 직접 선택하고 서비스 공급자에게 자신의 정보를 제공하는 대화형 방송 기술이 주요한 디지털서비스 요소로 자리잡고 있다. 본 논문에서는 국내외의 대화형 방송 기술 개발 현황을 살펴보고, 한국전자통신연구원에서 개발중인 대화형 위성통신방송 시스템 기술, 대화형 위성통신방송 단말기술, 대화형 위성원격교육 기술에 대하여 기술한다.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.10a
• /
• pp.294-297
• /
• 2003

In this paper we designed and measured HTS antenna array for Direct Broadcast Satellite (DBS) system. HTS antennas fabricated in this work were a four-element, 11.67 ㎓z, high-Tc superconducting (HTS) microstrip antenna array with corporate feed network and circular polarization for direct broadcas- ting satellite (DBS) system. Our antennas was designed and built on a 0.5 mm thick YBa2Cu3O7-x (YBCO) /MgO substrate. The measurement results showed good axial ratio, wide bandwidth a remarkable improvement over their metal counterpart.

• Journal of Positioning, Navigation, and Timing
• /
• v.2 no.1
• /
• pp.41-48
• /
• 2013

When the ground subsystem of Ground Based Augmentation System(GBAS) is installed at the airport, the functions and performance of subsystem should be evaluated through ground and flight testing at the pre-commissioning phase. In the case of GBAS flight testing, it can be conducted by the existing flight check aircraft, but the GBAS ground testing requires the development of specially customized equipment to perform the ground testing. Therefore, this paper describes the preliminary design of GBAS onboard test equipment which can be independently used for the GBAS ground testing and flight testing on a car and an aircraft.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.13-16
• /
• 1999

The terrestrial/satellite hybrid network may replace or supply the terrestrial network in some areas or certain application. Futhermore, it can play an important role in the development of B-ISDN due to their features of flexible wide coverage, independent of ground distances and geographical constraints, multiple access and multipoint broadcast. Also, satellite have the capability to supply terrestrial ATM and B-ISDN with flexible links for access networks as well as trunk networks. This paper describes the design and verification of the interworking protocol between terrestrial B-ISDN and satellite network. For the verification, the designed interworking protocol is modeled by Petri-net and analyzed by reachability tree.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.7
• /
• pp.1909-1918
• /
• 1999

The terrestrial/satellite hybrid network may replace or supply the terrestrial network in some areas or certain applications. For example, it may play a major role in global B-ISDN or in certain areas where the deployment of optical cable is not feasible, especially at the early stage of implementing terrestrial B-ISDN. Furthermore, it can play an important role in the development of B-ISDN due to their features of flexible wide coverage, independent of ground distances and geographical constraints, multiple access and multipoint broadcast. Also, satellite have the capability to supply terrestrial B-ISDN/ATM with flexible links for access networks as well as trunk networks. This paper describes the design and verification of the interworking protocol between terrestrial B-ISDN뭉 satellite network. For the verification, the designed interworking protocol is modeled by Petri-net and the model is analyzed by reachability tree.

• Journal of Advanced Navigation Technology
• /
• v.19 no.5
• /
• pp.345-353
• /
• 2015

In this paper, we proposed an information fusion method for enhancement of automatic dependent surveillance - broadcast (ADS-B) system which is one of the next generation navigation system. Although ADS-B provides better performance than traditional radar, ADS-B still has error due to dependence of global navigation satellite system (GNSS) information. In this paper, we improved the ADS-B performance using information fusion of multilateration (MLAT) and wide area multilateration (WAM). Information fusion provides accurate data compared to original data. Mostly, information fusion methods use Kalman filter or IMM(interacting multiple model) filter as a subfilter. However, we used Robust IMM filter as a subfilter to improve the aircraft tracking performance. Also, we use actual ADS-B data not virtual data to increase reliability of our information fusion method.

• Journal of Broadcast Engineering
• /
• v.2 no.1
• /
• pp.24-35
• /
• 1997

Basic and transmission video quality testing was performed in real-time mode using hardware video codec based on MPEG-2 MP@ML standard including subsequent transmitting and receiving satellite simulator unit. The double-stimulus Impairment scale method and the double-stimulus continous quality scale method based on CCIR 500-5 were used as an evaluation method. The whole digital broadcasting satellite system consisting of MPEG-2 codec, system mux/demux, channel codec, channel, modem, antenna, etc. was put into the overall video quality testbed and the basic and transmission error quality assessment was performed at various bitrates and BER for an integrated system performance evaluation. In transmission error video quality testing, transmission error video quality maintained on average above 3.9 point on the 5-point scale. The low-bit rate quality such as film mode(@2Mbps) highly depended on the statitical characteristics of video source and maintained on average around 2.7 point.