• 대한전자공학회논문지TC
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• 제48권10호
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• pp.20-28
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• 2011

이 논문은 위성항법시스템의 문제점인 위치오차와 실외음영지역을 해소하기 위하여 위성항법시스템과 비전시스템을 융합한 신뢰성있는 고정밀 측위 기술을 제안하였다. 동적단독측위에서 이동체는 이동 위치에 따라 사용할 수 있는 위성항법시스템의 수가 변화한다, 위치 측위를 위해서는 최소 4개 이상의 위성항법시스템으로부터 위치정보데이터를 수신 받아야 한다. 그러나 도심지역에서는 고층건물이나 장애물 또는 반사파에 의해 정확한 위치측위가 어렵다. 이러한 문제점을 해결하기 위하여 비전 시스템을 이용하였다. 위성항법시스템을 사용하기 열악한 도심지역의 특정 건물에 정확한 위치값을 결정해 놓는다. 그리고 비전시스템을 통해 특정 건물을 인식하고, 인식된 건물을 이용하여 위치오차를 보정해 준다. 이동체는 이동하면서 비전시스템을 이용하여 특정 건물을 인식하며 위치 데이터값을 만들어내고, 위치계산을 수정하여 안정되고 신뢰성있는 고정밀 위치측위를 할 수 있다.

• 한국위성정보통신학회논문지
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• 제7권3호
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• pp.121-129
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• 2012

현재까지 한국의 자국 우주기반 지역위성항법시스템은 개발되거나 구체적으로 계획되어 있지 않다. 그러나 국내 지역위성항법시스템의 개발요구는 여러 가지 수요 외적인 요인으로도 결정될 수 있으며, 커져가는 국내의 위성항법시스템에 대한 의존도는 결국 자국 위성항법시스템의 개발 및 보유를 궁극적으로 요구할 것으로 사료된다. 한반도 주변을 활용서비스 대상으로 설정하는 지역위성보강항법 시스템 또는 지역위성항법 시스템 둘 다 설계 궤도나 시스템 설계개념은 그리 선택의 여지가 많지 않다. 또한 우주감시 분야는 국내에서 막 태동하는 연구개발 분야이며 미래 한국형항법위성시스템을 보유했을 때 항법시스템의 유지와 항법메세지의 생성을 위해서 반드시 필요한 기술 분야이기도 하다. 이 연구에서는 한국보다 먼저 구축이 기대되는 일본의 준천정위성시스템의 한국 지역 활용도를 분석하고, 유사한 시스템을 한국에 적용했을 때의 활용도 분석, 독자적인 위성항법시스템을 도입했을 때 사용가능한 궤도 얼개 분석, 그리고 이차적인 추적시스템으로서 지상기반 광학추적시스템의 가관측성 등을 분석하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.331-336
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• 2002

Satellite positioning technology has been widely used in all kinds of military and civil land, marine, space and aeronautical target positioning tasks, navigation activities and accurate surveying measurements since 90s in the last century due to it advantage in providing all-weather, real-time, three dimensional and high precision positioning information, as well as speed and accurate timing information. By now, it has already formed a new hi-tech industry basically. This paper briefly reviews the development of the global satellite positioning and navigation technologies including the basic information of China′s "Plough navigation system", introduces the history of satellite positioning technology and its major application fields as well as the status quo of this being industrialized trade in China, gives an account of the writers′ vision for the application and prospect of the satellite positioning technologies in China, and approaches the tactics and stresses of the satellite positioning technology′s application and its industrialization future in China.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.872-875
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• 2012

Recently, China officially declared to operate its satellite positioning system, Beidou so called Compass. The system is currently having 10 orbiting satellites which regionally cover from Australia to Russia in the north. Moreover, the system will be planed not only to launch 6 navigation satellites in its orbit in 2012 but also to complete the system with 35 satellites in 2020. The China satellite navigation system can affect to the current circumstance of global satellite navigation world in terms of navigation parameters. In this paper, we investigate characteristics of multi-integrated GNSS involving Beidu-Compass system and discuss general issues involving visibility and GDOP.

• Journal of Positioning, Navigation, and Timing
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• 제12권4호
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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.

• Journal of Positioning, Navigation, and Timing
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• 제10권4호
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• pp.353-361
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• 2021

This paper presents the jamming effect on the L5 band of Global Navigation Satellite System (GNSS) by analyzing real data collected via measurement campaigns in Korea region. In fact, the L5 band is one of the dedicated bands for various satellite navigation systems such as Global Positioning System (GPS), Galileo, BeiDou (BDS), and Quasi Zenith Satellite System (QZSS). And this band is also allocated along with various systems used for aeronautical radio navigation systems (ARNS). Among ARNS, the Distance Measuring Equipment (DME) and the Tactical Air Navigation System (TACAN) are systems that transmit and receive strong power pulse signals, which may cause unintentional jamming in the reception of GNSS signals. In this paper, signals in the main lobe of GPS L5, Galileo E5a, BDS B2a, and QZSS L5 are collected in Korean region to confirm whether the jamming effect exists in the band. And then, the pulse blanking technique, which is a simple signal processing technique capable of responding to pulsed jamming, is applied to analyze the jamming effect of DME/TACAN on the L5 band.

• Journal of Positioning, Navigation, and Timing
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• 제12권2호
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• pp.167-176
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• 2023

This study presents the performance analysis of real-time orbit determination and prediction for navigation message generation of Regional Navigation Satellite System (RNSS). Since the accuracy of ephemeris and clock correction in navigation message affects the positioning accuracy of the user, it is essential to construct a ground segment that can generate this information precisely when designing a new navigation satellite system. Based on a real-time architecture by an extended Kalman filter, we simulated orbit determination and prediction of RNSS satellites in order to assess the accuracy of orbit and clock prediction and signal-in-space ranging errors (SISRE). As a result of the simulation, the orbit and clock accuracy was at 0.5 m and 2 m levels for 24 hour determination and six hour prediction after the determination, respectively. From the prediction result, we verified that the SISRE of RNSS for six hour prediction was at a 1 m level.

• International Journal of Aeronautical and Space Sciences
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• 제18권2호
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• pp.327-333
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• 2017

This study presents the orbit determination (OD) of a candidate Korea Regional Navigation Satellite System (KRNSS) using both inter-satellite links (ISLs) and ground observations. The candidate constellation of KRNSS is first introduced. The OD algorithm based on both ISL and ground observation is developed, and consists of three main components: dynamic model for Korean navigation satellites, measurement model for ISLs and ground observations, and the batch least-square filter for estimating OD parameters. As numerical simulations are performed to analyze the OD performances, the present study focuses on investigating the effects of ISL measurements on the OD accuracy of KRNSS. Simulation results show that the use of ISLs can considerably enhance the OD accuracy to one meter (design preference) under certain distributions of ground stations.

• 한국항행학회논문지
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• 제28권1호
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• pp.1-14
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• 2024

위치, 항법 및 시각정보 서비스를 제공하는 위성항법시스템은 위성시스템, 지상시스템, 사용자시스템으로 구성된다. 지상시스템의 구성요소인 감시국은 위성항법시스템의 서비스 제공 및 고장 검출을 위해, 위성항법 신호를 연속적으로 수집하고 위성의 SIS (signal-in-space) 고장과 수신기 및 다중반사파를 포함한 Local 고장과 같은 신호 이상을 검출하여 수신한 데이터와 검출 결과를 중앙처리국으로 전송하는 역할을 한다. 본 논문에서는 기존 위성항법시스템 감시국의 수신한 위성 신호에 대한 품질 판단 및 고장 검출을 위한 주요 모니터와 측정치 전처리 과정을 소개하고, 이를 활용하여 차세대 지역 위성항법시스템 (RNSS; regional navigation satellite system) 감시국의 구성요소와 아키텍처 및 알고리즘 개발 방안을 제시하였다.

• Journal of Positioning, Navigation, and Timing
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• 제1권1호
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• pp.23-27
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• 2012

Recently, devices like Personal Privacy Devices (PPD) are being employed to avoid the detection of one's location by GPS, and most PPD transmits swept CW signals. However, signals transmitted from PPD may interfere a precise location system based on GPS. Accordingly, in order to reduce interferences by PPD, a technique to locate an interferer is needed. In order to locate an interferer AOA method and TDOA method are generally used, TDOA method is known to be more accurate than AOA method. Unfortunately, TDOA method has a problem of ambiguity in obtaining measurements of swept CW interference. Thus, this paper design a localization algorithm based on TDOA method that can accurately locate an interferer transmitting swept CW signals by resolving problem of ambiguity. In addition, feasibility of the designed algorithm has been verified by simulation results.