• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.336-342
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• 2010

GPIR(GPS Position Information Revision) system is a new concept of GPS system which utilizes database containing the location of taking a picture by the existing GPS, an angle between a camera and a subject and the location information of buildings and minimizes the GPS's own margin of error and there by provides the services, such as location-guiding via GPS and way-guiding via navigation in an exact and precision way more than before. GPIR system comprehends the location of taking photos via GPS information saved in G-files, searches database in the direction of taking a photo at a photo-taking position via location information and the photo-taking directional angle. And GPIR system corrects the GPS information searched to the location of a subject, again saves such information in a G-file and is ready for receiving more detailed location of the subject. This study explores into the design and development of a receiver which a GPIR user is able to utilize its system as well as the design of the receiver's prototypes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.201-208
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• 1993

The emergence of the Global Positioning System(GPS) with its benefits of speed and economy now offers an opportunity to analyse, strengthen, densify and constitute the control network, in addition to providing mapping, cadastral and engineering control under the unfavorable conditions. This research aims at the using of GPS compared to conventional geodetic positioning techniques in Korean primary control networks. A GPS test network of 10km baselines, which is measured and analysed by Wild GPS-System 200, are compared to the distances from EDM and official coordinates, and relative GPS heights are transformed to the height differences on the mean sea level. The results of this study confirms that using GPS merely as a new type of instrument is the most powerful method for the densification of the control points retaining existing networks and existing computational procedures.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.4
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• pp.41-50
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• 2007

This study aims to suggest efficient setting up of GPS (Global Positioning System) for cadastral surveying. In order to perform it effectively, worldly used modern surveying technology GPS introduced. In a practical analysis, GPS observation had been performed in the research area and the results had been compared and analysed with the results of Total Station. As a results, it is shown that GPS is more efficient rather than current surveying method in terms of time, cost and economy. The results of GPS surveying were included in the scope of error tolerance, being accepted by cadastral laws, showing high accuracy of GPS surveying method. With the results of analysis, how to application of GPS for cadastral surveying was suggested.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.65-71
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• 2004

The Development of GPS practical using and systematic fixing for GPS Quality Control System on On-Line. Developed the program that can prove GPS quality about GPS permanent observation stations or user GPS data in server client system environment of Web-Based objectively Developed Save-module of graph display of analysis result data and reporter form. Developed the program for making an estimate of GPS satellite information in server client system environment of Web-Based. Designed that the Display can be possible and store estimate result can expresses the form such as Sky Plot, DOPs, Satellite Elevation, satellite number cf predict-time and then the result can be preserved for report form.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.612-619
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• 2011

Satellite navigation system such as GPS is becoming more important infrastructure for positioning, navigation and timing. But satellite navigation system is vulnerable to interferences because of the low received power, complementary navigation system such as eLoran is needed. In order to develop eLoran/GPS navigation system, integrated eLoran/GPS navigation algorithm is necessary. In this paper, new integrated eLoran/GPS navigation algorithm is proposed. It combines the position domain integration and the range domain integration to get accurate position with less computational burden. Also an eLoran/GPS evaluation platform is designed and performance evaluation of the proposed algorithm using the evaluation platform is given. The proposed algorithm gives an accuracy of the range domain integration with a computational load of the position domain integration.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.273-278
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• 2006

In order to use a GPS antenna for launch vehicles, it should be installed on the skin of the vehicle and be able to normally receive the live GPS signals during the vehicle's full flight mission. The GPS antenna on the surface of the launch vehicle is, however, exposed to higher temperature than inner equipments of the vehicle due to aerodynamic heating generated during the flight. Test specification of the GPS antenna for qualification of hot-temperature is determined to $+95^{\circ}C$ that is higher than inner components by $25^{\circ}C$. Test results in this paper show that the GPS antenna normally operates under the above environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.163-164
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• 2014

Pseudolite systems are used for backup systems of GPS satellite or indoor navigation systems. The pseudolite transmits GPS-like signal on the ground. Fundamentally, to estimate a position, clock synchronization among satellites is essential, because GPS receiver uses measurement based on TOA. Therefore, in order to improve the navigation performance in applications using pseudolite, clock synchronization with GPS satellites is required. This paper proposes design of monitoring system for pseudolite clock synchronization. The monitoring system analyzes clock synchronization accuracy of pseudolite and can be used for clock adjustment.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.2
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• pp.67-72
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• 2015

Power grid techniques are distributed over general power systems ranging from power stations to power transmission, power distribution, and users. To monitor and control the elements and performance of a power system in real time in the extensive area of power generation, power transmission, wide-area monitoring (WAM) and control techniques are required (Sattinger et al. 2007). Also, to efficiently operate a power grid, integrated techniques of information and communication technology are required for the application of communication network and relevant equipment, computing, and system control software. WAM should make a precise power grid measurement of more than once per cycle by time synchronization using GPS. By collecting the measurement values of a power grid from substations located at faraway regions through remote communication, the current status of the entire power grid system can be examined. However, for GPS that is used in general national industries, unexpected dangerous situations have occurred due to its deterioration and jamming. Currently, the power grid is based on a synchronization system using GPS. Thus, interruption of the time synchronization system of the power system due to the failure or abnormal condition of GPS would have enormous effects on each field such as economy, security, and the lives of the public due to the destruction of the synchronization system of the national power grid. Developed countries have an emergency substitute system in preparation for this abnormal situation of GPS. Therefore, in Korea, a system that is used to prepare for the interruption of GPS reception should also be established on a long-term basis; but prior to this, it is required that an evaluation technique for the time synchronization performance of a GPS receiver using an atomic clock within the power grid. In this study, a monitoring system of time synchronization based on GPS at a power grid was implemented, and the results were presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.425-428
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• 2008

To overcome the limitation of tracking speed on signal-shaded area and the discontinuity of GPS, we present a system which estimates the speed of moving object using GPS and accelerometer. This system is designed to correct accelerometer's noises which are caused by vibration and impact to the object and errors of itself, from the navigation information of GPS receiver and accelerometer which are installed to moving object. And using this information, it estimates the speed of moving object on GPS signal-shaded area to complement discontinuity of GPS navigation information. We designed Kalman Filter structure using GPS and accelerometer to apply this system, and verify that the system can estimate object's speed on GPS signal-shaded area. Finally, we present the possibilities applying to telematics systems like automatic navigation system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.3
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• pp.283-292
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• 2005

After USA removed the Selective Availability (SA), Global Positioning System (GPS) has monopolized the world market and other countries have been depended on GPS, absolutely. So the other countries, Russia, European Community (EC) and Japan, which apprehend to monopolize in technical and strategic parts, are developing the next generation GNSS including GLONASS Galileo and JRANS. And the countries are planning to provide the another GNSS. This research has focused on the next generation GNSS system based on GPS and Galileo system with developing a GNSS simulation software, named as GlMS2005, which generates and analyzes satellite constellation and measurements. Based on the software, a variety of simulation tests have been carried out to recognize limits of GPS-only system and potential benefits of integrated GPS/Galileo positioning in terms of satellite geometry strength and solution accuracy.