• Journal of Positioning, Navigation, and Timing
• /
• v.9 no.2
• /
• pp.99-115
• /
• 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
• /
• v.11 no.4
• /
• pp.333-339
• /
• 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.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2017.11a
• /
• pp.16-18
• /
• 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.

• Journal of Navigation and Port Research
• /
• v.42 no.2
• /
• pp.79-86
• /
• 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.

• Journal of Advanced Navigation Technology
• /
• v.20 no.1
• /
• pp.37-44
• /
• 2016

Republic of Korea has established its performance-based navigation (PBN) implementation plan in 2010 for ensuring a smooth transition to PBN operations and relevant new flight procedures are being developed in accordance with the roadmap. Various Navigation aids (NAVAIDs) like global navigation satellite systems (GNSS), distance measuring equipment (DME), VHF omnidirectional range (VOR), inertial navigation system (INS) are used to support PBN procedures. Among them, GNSS would play a central role in PBN implementation. However, vulnerability of satellite navigation signals to artificial and natural interferences has been discovered and various alternative positioning, navigation and timing (APNT) technologies are under development in many countries. In this paper, we study whether continuous PBN operations can be achievable without GNSS signals. As a result, it shows that some of the domestic airports require the construction of APNT in the approach area.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.1
• /
• pp.49-57
• /
• 2019

The International Maritime Organization is developing a maritime safety system called eNavigation in order to effectively respond to accidents occurring on board vessels. Korea is actively participating in the development of eNavigation and is developing Korean eNavigation by adding its own concept to eNavigation of the IMO. eNavigation is designed to provide various functions for marine safety. The data required for each function is various such as spatial data, relational data, file, weather grid. Therefore, there is a need for a system that can appropriately provide heterogeneous data suitable for eNavigation to each eNavigation's service system. In this paper, we analyzed the kinds of data needed for e-Navigation and designed the architecture of heterogeneous data service system that could provide these data properly.

• Journal of Mechanical Science and Technology
• /
• v.19 no.8
• /
• pp.1529-1543
• /
• 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)
• /
• v.13 no.9
• /
• pp.4606-4623
• /
• 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
• /
• v.9 no.4
• /
• pp.305-317
• /
• 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.

• Journal of Institute of Control, Robotics and Systems
• /
• v.19 no.2
• /
• pp.95-101
• /
• 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.