• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.33-37
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• 2006

Since 1993, the civil aviation community through RTCA (Radio Technical Commission for Aeronautics) and the ICAO (International Civil Air Navigation Organization) have been working on the definition of GNSS augmentation systems that will provide improved levels of accuracy and integrity. These augmentation systems have been classified into three distinct groups: Aircraft Based Augmentation Systems (ABAS), Space Based Augmentation Systems (SBAS) and Ground Based Augmentation Systems (GBAS). The last one is an implemented system to support Air Navigation in CAT-I approaching operation. It consists of three primary subsystems: the GNSS Satellite subsystem that produces the ranging signals and navigation messages; the GBAS ground subsystem, which uses two or more GNSS receivers. It collects pseudo ranges for all GNSS satellites in view and computes and broadcasts differential corrections and integrity-related information; the Aircraft subsystem. Within the area of coverage of the ground station, aircraft subsystems may use the broadcast corrections to compute their own measurements in line with the differential principle. After selection of the desired FAS for the landing runway, the differentially corrected position is used to generate navigation guidance signals. Those are lateral and vertical deviations as well as distance to the threshold crossing point of the selected FAS and integrity flags. The Department of Applied Science in Naples has create for its study a virtual GBAS Ground station. Starting from three GPS double frequency receivers, we collect data of 24h measures session and in post processing we generate the GC (GBAS Correction). For this goal we use the software Pegasus V4.1 developed from EUROCONTROL. Generating the GC we have the possibility to study and monitor GBAS performance and integrity starting from a virtual functional architecture. The latter allows us to collect data without the necessity to found us authorization for the access to restricted area in airport where there is one GBAS installation.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.305-313
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• 2016

International Civil Aviation Organization (ICAO) has recommended the adoption of performance-based navigation (PBN), which utilizes global navigation satellite system (GNSS). As a part of efforts to adopt PBN in South Korea, preparations have been made to implement GNSS. In Oct. 2014, Korea augmentation satellite system (KASS) was officially launched for development. A set of navigation devices need to be on-board for an airplane to utilize GNSS. GNSS navigation devices are used for different phases of flights through en-route, terminal, departure, approach and a wide variety of specification standards have been proposed for GNSS navigation. In this paper, we investigate the many proposed standards for GNSS navigation devices and their interfaces. This paper can be useful for designing procedures and flight test used in KASS implementation.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.2
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• pp.207-213
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• 2024

This paper examines the frame boundary detection performance for a satellite navigation augmentation signal orthogonally modulated with Hadamard code to determine the number of message preamble bits. Simulation results show that, even in weak signal environments, designing the message preamble with 32 bits is recommended for achieving stable frame boundary detection.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.4
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• pp.349-358
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• 2023

The Satellite-Based Augmentation System (SBAS) plays a significant role in the fields of aviation and navigation: it corrects signal errors of the Global Navigation Satellite System (GNSS) and provides integrity information to facilitate precise positioning. These SBAS systems have been adopted as international standards by the International Civil Aviation Organization (ICAO). In recent SBAS system design, the Minimum Operational Performance Standards (MOPS) defined by the Radio Technical Commission for Aeronautics (RTCA) must be followed. In October 2014, South Korea embarked on the development of a Korean GPS precision position correction system, referred to as Korea Augmentation Satellite System (KASS). The goal is to achieve APV-1 Standard of Service Level (SoL) service level and acquisition of CAT-1 test operating technology. The first satellite of KASS, KASS Prototype 1, was successfully launched from the Guiana Space Centre in South America on June 23, 2020. In December 2022 and June 2023, the first and second service signals of KASS were broadcasted, and full-scale KASS correction signal broadcasting is scheduled to start at the end of 2023. The aim of this study is to analyze the precision of both the GNSS system and KASS system by comparing them. KASS is also compared with Japan's Multi-functional Satellite Augmentation System (MSAS), which is available in Korea. The final objective of this work is to validate the usefulness of KASS correction navigation in the South Korean operational environment.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1213-1214
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• 2008

In this paper, we describe introduction of GNSS Test & Evaluation Facility developing in "Korean aerospace research Institute" and UML based design results of GNSS Augmentation System Test & Evaluation Simulator especially.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.4
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• pp.193-202
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• 2016

The Korea Augmentation Satellite System (KASS), which is under development in Korea as a Satellite Based Augmentation System (SBAS) is expected to broadcast SBAS messages to air space in Korea according to the international standards defined by the International Civil Aviation Organization (ICAO) and the Radio Technical Commission for Aeronautics (RTCA). Around 13 SBAS messages are broadcast in every second to transmit augmentation information which can be applicable to a wide area in common. Each of the messages requires a different update interval and time-out according to the characteristics, purpose, and importance of transmitted information, and users should receive and combine multiple SBAS messages to calculate SBAS augmented information. Thus, a time to take acquiring first SBAS position by users differs depending on broadcasting various SBAS messages with which order and intervals. The present paper analyzes the considerations on message scheduling for broadcasting of KASS augmentation information and proposes a design of KASS message scheduler using the considerations. Compared to existing SBAS systems, which have a wide range of service area, a service area of the KASS is limited to Korea only. Thus, the numbers of ionosphere grid points and satellites to be augmented are expected to be smaller than those of existing SBAS. By reflecting this characteristic to the proposed design, shortening of broadcast interval of KASS message is verified compared to existing SBAS and a measure to increase a speed of acquisition of user navigation solution is proposed utilizing remaining message slots. The simulation result according to the proposed measure showed that the maximum broadcast interval can be reduced by up to 20% compared to that of existing SBAS, and users can acquire KASS position solution faster than existing SBAS.

• Journal of Advanced Navigation Technology
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• v.12 no.6
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• pp.567-573
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• 2008

According to the ICAO's Global Air Navigation Plan for CNS/ATM - Communications, Navigation, and Surveillance - systems, employing digital technologies, including satellite systems together with various levels of automation, are to be applied in support of a seamless global air traffic management system. For the future navigation, the focus of future implementation efforts can be placed entirely on an expected gradual migration toward GNSS-based navigation, Korea has been considered various options for airspace GNSS augmentation system: GBAS, SBAS and GRAS. This paper discusses current status and future trend of GNSS airspace navigation systems, and presents the results of possible augmentation options and scenarios to analyze system availabilities which could lead to the conclusion of the best program for Korea. The results showed that Korea could have sufficient availabilities from en-route to CAT-I approach with ABAS and GBAS. The study was in cooperated with MITRE, an American research company.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.165-170
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• 2006

In the Civil Aviation field, the international trend (through ICAO, EUROCONTROL) is to adopt one positioning system that allows to follow more flight phases. This will allow to release themselves by ground installations and optimize the traffic flows following the aRea Navigation (RNAV) concept. In order to realize this goal the European Scientific Community are focusing on Augmentation Systems based on Satellite infrastructure (SBAS - Satellite Based Augmentation System) and on Ground based ones (GBAS - Ground Based Augmentation System). The goal of this work is to present some results on SBAS and GBAS performances. Regarding SBAS, the Department of Applied Sciences of Parthenope University, after the acquisition of a Novatel OEM4 SBAS receiver has created a monitoring station that reflect as much as possible a standardized measure environment for EGNOS Data Collection Network (EDCN), established by Eurocontrol. The Department of Applied Science has decided to carry out a own monitoring survey to verify the performance of EGNOS that can be achieved in South Europe region, a zone not very covered by official (EDCN) monitoring network. Regarding GBAS, we started from a data set of measurements carried out at the GBAS of Milan-Linate airport where we work on a ground installation (GMS - Ground Monitoring Station) that supervises the GBAS signal and that represent, for our purposes, the Aircraft subsystem. So the set of data collected is to be considered in RTK mode and after the measures session we processed them with the software PEGASUS v 4.11. Both experiences give us the possibility to evaluate the GNSS1 performance that can be achieved.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.2
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• pp.79-85
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• 2019

The mission tasks of polar exploration utilizing unmanned systems such as glacier monitoring, ecosystem research, and inland exploration have been expanded. To facilitate unmanned exploration mission tasks, precise and robust navigation systems are required. However, limitations on the utilization of satellite navigation system are present due to satellite orbital characteristics at the polar region located in a high latitude. The orbital inclination of global positioning system (GPS), which was developed to be utilized in mid-latitude sites, was designed at $55^{\circ}$. This means that as the user is located in higher latitudes, the satellite visibility and vertical precision become worse. In addition, the use of satellite-based wide-area augmentation system (SBAS) is also limited in higher latitude regions than the maximum latitude of signal reception by stationary satellites, which is $70^{\circ}$. This study proposes a local-area augmentation system that additionally utilizes Global Navigation Satellite System (GLONASS) considering satellite navigation system environment in Polar Regions. The orbital inclination of GLONASS is $64.8^{\circ}$, which is suitable in order to ensure satellite visibility in high-latitude regions. In contrast, GLONASS has different system operation elements such as configuration elements of navigation message and update cycle and has a statistically different signal error level around 4 m, which is larger than that of GPS. Thus, such system characteristics must be taken into consideration to ensure data integrity and monitor GLONASS signal fault. This study took GLONASS system characteristics and performance into consideration to improve previously developed fault detection algorithm in the local-area augmentation system based on GPS. In addition, real GNSS observation data were acquired from the receivers installed at the Antarctic King Sejong Station to analyze positioning accuracy and calculate test statistics of the fault monitors. Finally, this study analyzed the satellite visibility of GPS/GLONASS-based local-area augmentation system in Polar Regions and conducted performance evaluations through simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1861-1867
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• 2016

Korea augmentation satellite system (KASS), which is a satellite-based augmentation system tailored for Korea, was launched for development in 2014. SBAS is a standard for aviation but it can also be utilized in non-aviation applications. The type and content of transmitted in SBAS data format are restricted. In order to utilize SBAS in fields that require the precision within centimeters, additional information has to be transmitted. It is important that data transmitted in nonstandard SBAS data not affect any operation of SBAS equipment. In this paper, we propose a non-standard SBAS data transmission method applicable to non-aviation applications that does not affect aviation SBAS receivers.