• Journal of Positioning, Navigation, and Timing
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• 제9권2호
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• pp.99-115
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• 2020

Since GNSS is easily affected by jamming and/or spoofing, alternative navigation systems can be operated as backup system to prepare for outage of GNSS. Alternative navigation systems are being researched over the world, and a multi-radio integrated navigation system using alternative navigation systems such as KNSS, eLoran, Loran-C, DME, VOR has been researched in Korea. Least Square or Kalman filter can be used to estimate navigation parameters in the navigation system. A large number of measurements of the Kalman filter may lead to heavy computational load. The decentralized Kalman filter and the federated Kalman filter were proposed to handle this problem. In this paper, the decentralized Kalman filter and the federated Kalman filter are designed for the multi-radio integrated navigation system and the performance evaluation result are presented. The decentralized Kalman filter and the federated Kalman filter consists of local filters and a master filter. The navigation parameter is estimated by local filters and master filter compensates navigation parameter from the local filters. Characteristics of three Kalman filters for a linear system and nonlinear system are investigated, and the performance evaluation results of the three Kalman filters for multi-radio integrated navigation system are compared.

• Journal of Positioning, Navigation, and Timing
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• 제11권4호
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• pp.333-339
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• 2022

The satellite navigation system was developed for the purpose of calculating the location of local users, starting with the Global Positioning System (GPS) in the 1980s. Advanced countries in the space industry are operating Global Navigation Satellite System (GNSS) that covers the entire earth, such as GPS, GLONASS, Galileo, and BeiDou, by establishing satellite navigation systems for each country. Regional Navigation Satellite Systems (RNSS) such as QZSS and NavIC are also in operation. In the early 2010s, only GPS and GLONASS could calculate location using a single system for location determination. After 2016, the EU and China also completed the establishment of GNSS such as Galileo and BeiDou. As a result, satellite navigation users can benefit from improved availability of GNSS. In addition, before Galileo and BeiDou's Full Operational Capability (FOC) declaration, they used combined navigation algorithms to calculate the user's location by adding another satellite navigation system to the GPS satellites. Recently, it may be possible to calculate a user's location for each navigation system using the resources of a single system. In this paper, we evaluated the performance of single system navigation and combined navigation solutions of GPS, GLONASS, Galileo, BeiDou and QZSS individual navigation systems using high-performance GNSS receivers.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2017년도 추계학술대회
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• pp.16-18
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• 2017

미래의 해상 환경에서 e-Navigation은 더욱 중요한 역할을 수행할 것이다. e-Navigation의 목적인 해양 사고 저감과 운항 효율화를 달성하기 위하여 다양한 해사 서비스들의 개발은 필수적이며, 이러한 서비스들을 관리할 수 있는 해사 서비스 관리 기술이 필요하다. 본 연구에서는 한국형 e-Navigation인 SMART-Navigation 내에서 다양한 해사 서비스를 체계적으로 관리하고 이종 통신 간 통신 수단의 전환에도 통신 단절 없이 서비스 사용자에게 등록된 해사 서비스의 메타 데이터를 전달하는 해사 서비스 레지스트리를 개발하기 위한 기본 개념과 구조를 제시하고자 한다.

• 한국항해항만학회지
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• 제42권2호
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• pp.79-86
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• 2018

Common Maritime Data Structure (CMDS) is commonly used by shore and ship users in e-Navigation data domain. In the overarching of e-Navigation architecture, IHO uses S-1XX, a digital exchange standard for next-generation marine information, as data exchange standard. The current CMDS has the advantage of intuitively recognizing the overall structure of e-Navigation. However, it has disadvantage in that it does not allow stakeholders to easily understand benefits that e-Navigation can provide when implementing e-Navigation. In this study, the direction of improving existing system for effective e-Navigation implementation was proposed considering RCOs (Risk Control Options) with expected composition of ship/ shore/ communication system by sector.

• 한국항행학회논문지
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• 제20권1호
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• pp.37-44
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• 2016

한국은 성능기반항행 (PBN; performance-based navigation)으로 전환하기 위한 단계적 PBN 이행계획을 2010년에 수립하고 로드맵에 따른 새로운 비행절차를 개발 중에 있다. PBN 비행절차에는 GNSS (global navigation satellite systems), DME (distance measuring equipment), VOR (VHF omnidirectional range), INS (inertial navigation system) 등의 항행시설 (NAVAID; navigation aid)이 활용되는 것으로 되어있다. 그 중에서 GNSS를 이용한 PBN 업무제공이 중심을 이루고 있는 실정이다. 그러나 위성항법신호의 인위적, 자연적 간섭에 의한 취약성이 발견됨에 따라 세계 각국은 다양한 대안항법(APNT; alternative positioning, navigation and timing) 기술을 연구하고 있다. 본 논문에서는 GNSS 신호가 가용하지 않을 경우 기존의 항행시스템으로 지속적인 PBN 운항이 가능한지를 분석하였으며, 결과적으로 국내 일부 공항은 접근 단계 구역에서 대안항법의 구축이 필요한 것으로 나타났다.

• 한국정보전자통신기술학회논문지
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• 제12권1호
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• pp.49-57
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• 2019

국제해사기구(IMO)는 해상을 항해하는 선박에 대해, 해상사고의 인적요인이 발생하지 않도록 e-Navigation이라는 새로운 해상안전 지원체계를 개발하고 도입하려 하고 있다. 한국은 e-Navigation 개발에 적극적으로 참여하여 e-Navigation 에 자체적으로 개발한 개념을 더해 한국형 e-Navigation인 '차세대 해양안전종합관리체계 기술'을 개발하고 있으며 2019년 도입을 목표로 하고 있다. 한국형 e-Navigation은 해양안전을 위한 다양한 기능을 제공할 수 있도록 설계되고 있는 만큼 각 기능별로 필요한 데이터의 종류가 공간 데이터와 일반 데이터, 파일, 기상 그리드등 다양하다. 따라서 이들 데이터를 eNavigation의 각 기능 서비스 시스템에 적절히 제공할 수 있는 시스템이 필요하게 되었다. 이에 본 논문에서는 한국형 e-Navigation에서 필요로 하는 데이터를 분석하고 이러한 이종 데이터를 제공할 수 있도록 REST API를 이용한 이종 데이터 서비스 시스템의 아키텍처를 설계하였다.

• Journal of Mechanical Science and Technology
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• 제19권8호
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• pp.1529-1543
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• 2005

Recently an unmanned aerial vehicle (UAV) has been widely used for military and civil applications. The role of a navigation system in the UAV is to provide navigation data to the flight control computer (FCC) for guidance and control. Since performance of the FCC is highly reliant on the navigation data, a fault in the navigation system may lead to a disastrous failure of the whole UAV. Therefore, the navigation system should possess a fault detection and isolation (FDI) algorithm. This paper proposes an attitude determination GPS/INS integrated navigation system with an FDI algorithm for a UAV. Hardware for the proposed navigation system has been developed. The developed hardware comprises a commercial inertial measurement unit (IMU) and the integrated navigation package (INP) which includes an attitude determination GPS (ADGPS) receiver and a navigation computer unit (NCU). The navigation algorithm was implemented in a real-time operating system with a multi-tasking structure. To evaluate performance of the proposed navigation system, a flight test has been performed using a small aircraft. The test results show that the proposed navigation system can give accurate navigation results even in a high dynamic environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권9호
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• pp.4606-4623
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• 2019

Nowadays modern cities develop in a very rapid speed. Buildings become larger than ever and the interior structures of the buildings are even more complex. This drives a high demand for precise and accurate indoor navigation systems. Although the existing commercially available 2D indoor navigation system can help users quickly find the best path to their destination, it does not intuitively guide users to their destination. In contrast, an indoor navigation system combined with augmented reality technology can efficiently guide the user to the destination in real time. Such practical applications still have various problems like position accuracy, position drift, and calculation delay, which causes errors in the navigation route and result in navigation failure. During the navigation process, the large computation load and frequent correction of the displayed paths can be a huge burden for the terminal device. Therefore, the navigation algorithm and navigation logic need to be improved in the practical applications. This paper proposes an improved navigation algorithm and navigation logic to solve the problems, creating a more accurate and effective augmented reality indoor navigation system.

• Journal of Positioning, Navigation, and Timing
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• 제9권4호
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• pp.305-317
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• 2020

The navigation message is composed of the information contained in the message and the structure for transmitting this information. In order to design a navigation message, considerations in terms of message content and message structure must be elicited. For designing a Korea Positioning System (KPS) navigation message, this paper explains performance indicators in terms of message structure and message content. Most of the performance analysis of GNSS navigation messages already in operation was performed only for Time-to-first-fix-Data (TTFFD). However, in the navigation message, the message content is composed of Clock-Ephemeris Data (CED) and additional information. So, this paper proposes a new performance indicator R_(Non-CED) that can be analyzed from the viewpoint of receiving additional information along with an explanation of TTFFD focusing on the CED reception time. This paper analyze the performance in terms of message structure using these two performance indicators. The message structures used for analysis are the packetized message protocol like GPS CNAV and the packetized and fixed pattern message protocol like GPS CNAV-2. From the results, it is possible to proffer how KPS navigation messages can have better performance than GPS navigation messages. And, these two performance indicators, TTFFD and R_Non-CED, can help to design the minimum TTFF required performance of KPS navigation messages.

• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.95-101
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• 2013

The paper investigates the geometric effect of landmarks to the navigation error in the landmark based 3D vision navigation and introduces the INS/Vision integrated navigation system considering its effect. The integrated system uses the vision navigation results taking into account the dilution of precision for landmark geometry. Also, the integrated system helps the vision navigation to consider it. An indirect filter with feedback structure is designed, in which the position and the attitude errors are measurements of the filter. Performance of the integrated system is evaluated through the computer simulations. Simulation results show that the proposed algorithm works well and that better performance can be expected when the error characteristics of vision navigation are considered.