• Journal of Navigation and Port Research
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• v.37 no.1
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• pp.49-54
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• 2013

This paper describes the progress and results of 'Wide Area Differetial GNSS (WA-DGNSS) Development' project which is supported by Korea Ministry of Land, Transport and Maritime Affairs. This project develops the main algorithm of the WA-DGNSS which can guarantee the improved accuracy, availability and integrity all over the Korean peninsula. After the establishment of WA-DGNSS ground system, a real time demonstration using pseudolite will be conducted. Product of this project will be directly utilized in Korean Satellite Based Augmentation System(SBAS) development project which is planned to be started from 2014.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.1-8
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• 2007

Loran-C of ground transmitting station base that can prevent confusion of country navigation system and give BACK-UP function about electric wave navigation comparing utilization incapability state about GPS(Global Positioning System) infra that user is spreading rapidly over our society whole such as sea/aviation safety, vehicles navigation, minuteness agriculture, minuteness measurement in this treatise practical use of Loran-C navigation propose. Executed ASF(Additional Secondary Phase Factor) production and an application experiment Loran-C by location error improvement way to enhance practical use value. By the result Loran-C in conclusion that can improve location error 100~400m remarkably by 10~65m reach. Also, production extent is latitude when go composition medium and bends cotton at ASF revision table utilization of land area, this smell is judged to be suitable hardness 10 minutes. And notable location error improvement and numeric of GPS BACK-UP function are judged to be possible at a ASF revision table application to Korea Peninsula whole area hereafter.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.65-72
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• 2010

In this study, the performances of a medium grade IMU which is aimed for Mobile Mapping System and a low grade IMU for pedestrian navigation are analyzed through simulations under GPS signal blockage. In addition, an analysis on the accuracy improvement of barometer, electronic compass, or multi-sensor(combination of barometer and electronic compass) to correct medium grade or low grade IMU errors in the situation of GPS signal blockage is performed. With the medium grade IMU, the three dimensional positioning error from INS exceeds the demanded accuracy of 5m when the block time is over 30 seconds. When we correct IMU with barometer, compass, or multi-sensor, however, the demanded accuracy is maintained up to 60 seconds. In addition, barometer is more effective than the electronic compass when they are combined. In case of low grade IMU like MEMS IMU, the three dimensional positioning error from INS exceeds the demanded accuracy of 20m when the block time is over 15 seconds. When we correct INS with barometer, compass, or multi-sensor, however, the demanded accuracy is maintained up to 15 seconds in simulation results. On the contrary to medium grade IMU, electronic compass is more effective than the barometer in case of low velocity such as pedestrian navigation. It is expected that the analysis suggested a method to decrease position or attitude error using aided sensor integration when MMS or pedestrian navigation is operated under 1he environment of GPS signal blockage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.374-377
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• 2012

GNSS(Global Navigation Satellite System) based land transportation infrastructure system is consists of receiving station and central station. The functions of the central system include receiving station's data gathering and decoding, carrier correction and integrity information generated, transmission of data in real-time. In general, The central station architecture should take into account various important points relating to hardware/software of system, data archiving and checking, availability and continuity of operation, etc. There is a fundamental need for a generic design capable of being used in any situation. Also, There is need to develop an expandable and interoperable central station architecture. In this paper, the process of design and manufacture and verification will be introduced.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.815-821
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• 2021

This study addresses on the design of performance monitoring system for the time synchronization service of the enhanced long-range navigation (eLoran) system, which has a representative ground-wave radio broadcast system capable of providing positioning, navigation, timing and data (PNT&D) services. The limitations of time-synchronized systems due to the signal vulnerabilities of the global navigation satellite system (GNSS) are explained, and the performance monitoring system for the eLoran timing service as a backup to the GNSS is proposed. The time synchronization service using eLoran system as well as system configurations and the user requirements in the differential Loran (dLoran) system are described to monitor the time synchronization performance. The results of the designed system are presented for long-term operation in the eLoran testbed environment. As the results of time performance monitoring, we were able to verify the time synchronization precision within 43.71 ns without corrections, 22.52 ns with corrections. Based on these results, the eLoran system can be utilized as a precise time synchronization source for GPS timing backup.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.71-73
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• 2012

하드웨어 방식의 DGPS 기준국 시스템을 개선한 차세대 DGPS 기준국 아키텍처인 소프트웨어 DGPS 기준국 시스템은 하드웨어 방식에서 발견된 많은 문제점을 개선한다. 그러나, 초기의 소프트웨어 DGPS 기준국 시스템은 차세대 아키텍처를 충실히 따르고 있기는 하지만 소프트웨어의 구조에 단점을 내포하고 있어 실제 적용에 어려움이 있다. 본 논문에서는 기존 소프트웨어 DGPS 기준국 시스템의 단점을 보완하고 구조를 개선한 새로운 아키텍처를 설계하고 이 아키텍처를 기반으로 한 실제 소프트웨어를 구현한다.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.83-92
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• 2007

In this paper, we present a design and implementation of three dimensional pointing device using Inertial Navigation System(INS) that acquires coordinates and location information without environmental dependancy. The INS measures coordinates based on the data from gyroscope and accelerometer and corrects the measured data from accelerometer using Kalman-Filter. In order to implement the idea of three dimensional pointing device, we choose a three dimensional Space-recognition mouse and use RFIC wireless communication to send a measured data to receiver for printing out the coordinate on display equipment. Based on INS and Kalman-Filter theoretical knowledge, we design and implement a three dimensional pointing device and verified the usability as an input device that can capture a human's move. also, we describe the applicability of this device in ubiquitous computing environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.298-303
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• 2011

최근 한반도의 잇따른 북한의 Jamming(교란신호)으로 인해 무선통신 기반 산업에 피해사례가 늘고 있다. 이에 국토해양부(위성항법중앙사무소)에서 운영중인 위성항법보정시스템(이하 "DGPS") 데이터 분석하였다. 그 결과 2010년도 발생한 재밍과 달리 2011년도에는 DGPS 기준국/감시국에서는 감지가 되지 않은 것으로 분석 되었으나, 피해 현황을 조사하여 이를 토대로 범국가적 대책방안(항행 백업시스템 개발, 유관기관과의 정보공유를 통한 감지 통합시스템 구축) 및 DGPS 운영 효율성 확보방안(감시국 신설, 실시간 감시프로그램 강화 등)에 대하여 제안하였다.

• Journal of Navigation and Port Research
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• v.38 no.2
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• pp.121-126
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• 2014

This paper suggests a new algorithm to provide low-cost GPS modules with DGPS service, which corrects the error vector in the already-calculated position by projecting range corrections to position domain using the observation matrix calculated from the satellite elevation and azimuth angle in the NMEA GPGSV data. The algorithm reduced the horizontal and vertical RMS error of U-blox LEA-5H module from 1.8m/5.8m to 1.0m/1.4m during the daytime. The algorithm has advantage in improving the performance of low-cost module to that of DGPS receiver by a software update without any correction in hardware, therefore it is expected to contribute to the vitalization of the future high-precision position service infrastructure by reducing the costumer cost and vender risk.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.72-77
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• 2017

The Satellite Based Augmentation System (SBAS) broadcasts to users integrity and correction information for Global Navigation Satellite System (GNSS) such as GPS and GLONASS using geostationary orbit (GEO) satellites. In accordance with the recommendation of the International Civilian Aeronautical Organization (ICAO) to introduce SBAS until 2025, a Korean SBAS system development / construction project is underway with the Ministry of Land, Transport and Maritime Affairs. Korea Augmentation Satellite System (KASS) is a high precision GPS correction system which is composed of KASS Reference Station (KRS), KASS Processing Station (KPS), KASS Uplink Station (KUS), KASS Control Station (KCS) and GEO satellites. In this paper, we provided the conceptual design of the KASS uplink station, which is composed of the Signal Generator Section (SGS) and the Radio-Frequency Section (RFS), and interface between the KASS ground sector and the GEO satellite.