• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.4
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• pp.411-418
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• 2004

This paper is the study about a method for determining the azimuth of a baseline by measuring the apparent direction of the Sun. It is simple to realize this method, as it requires, in addition to the apparent direction of the Sun already measured, the observation time and the latitude and the longitude of the survey point. Comparing the azimuths determined by this method and those determined by the PDGPS(Post Processed Differential GPS) on 3 different baselines, the differences(PDGPS - this method) between the azimuths determined by two methods were -13", +45" and +24" respectively. It can be an effective and rapid tool in cases that require the accuracy lower than 1 arc-min.than 1 arc-min.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.155-165
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• 2008

A method to determine the azimuth of a baseline by using the measured apparent directions of the Sun, the measurement time and the latitude and the longitude of the survey point. Comparing the azimuths determined by this method and those determined by the PDGPS(Post Processed Differential GPS) on 3 different baselines, the differences (this method - PDGPS) between the azimuths determined by two methods were -13", +45" and +24" respectively. This method can be used as an effective and rapid tool in cases that require the accuracy lower than 1 arc-min.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.55-60
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• 2003

As the distance between GPS rover station and GPS base station increases, more decorrelated positioning errors limit the ability for PDGPS(Precise Differential GPS). The objective of this paper is to present the improvement of using VRS(virtual reference station) based on multiple GPS reference station network to single reference station for static positioning in post-processing mode. For this, the VRS observations from GPS observations of real reference stations are derived by using Web service in post-mode. The coordinates of check point post-processed by 27 kind of VRS observations compared with the known ones.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.799-806
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• 2004

Recently, as the forerunner in establishing the Northeast Asia's logistics base, a lot of marine engineering works such as new ports and container terminals, extension of old ports, new bridges, land reclamation etc. have been progressed. Parallel to it, there is also an increasing demand for improving the safety of construction. In this situation, high resolution seismic reflection profiling can be well used, attempting to classify rocks and sediments under water, if possible, to delineate the distribution of grain sizes in sediments not only for calculating the cost of removing sediments from harbour's channels, but also for estimating the bearing capacities for bridge or port construction. However, the results from the corresponding reflection survey that has been in operation in our country can not be effectively used for engineering purposes mostly due to the insufficient resolution. Thus. in this paper, two innovative strategies are introduced to enhance resolution. The one deals with a newly designed exploration barge that will help reduce several kinds of noises encountered electrically or operationally. The other is associated with an establishment of optimum measuring system comprising e.g. a specially devised hydrophone with a combination of 7 piezoelectric elements. Field experiments performed at Busan harbour are illustrated. The quality of acquired data was thereby fundamentally improved in comparison with that obtained at the same time in a conventional way.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.353-360
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• 2007

KIGAM has installed a FLARE+ continuous geomagnetic observation system in 1998 in Daejeon of which the IAGA identification code is DZN. The coordinates of the absolute measurement plinth precisely determined by the PDGPS(Post-Processing Differential Global Positioning System) is (127-21-37.19E, 36-22-43.96N, 45.93 m) in WGS84 for the horizontal and from the geoid surface for the vertical. Periodically we have conducted the absolute geomagnetic measurement on the plinth above. We have processed the continuous time-variation 3-axis geomagnetic data measured on arbitrary sensors' coordinates in the observatory and absolute geomagnetic data together to get as the results the time-variation H(orizontal), D(eclination), Z(vertical down), F(scalar calculated from 3 components) and P(Proton Precession Magnetometer Data). We have compared our own data with those calculated from the 10th generation IGRF(International Geomagnetic Reference Field). All the measured data in the DZN Observatory can be acquired through the website http://geomag.kigam.re.kr.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.2
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• pp.105-116
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• 2004

According to the developing advanced techniques and removal of Selective Availability, much research has been conducted to improve the accuracy of GPS positioning in absolute and relative mode by estimating the nuisance parameters such as atmospheric effect, clock errors and multipath. Especially, the continuous effort of establishing the CORS in many countries and the effort of ICS making effective global networking make more application areas and the necessity of more precise location is being increased. Some of the countries like German, Japan and Swiss already utilized the Virtual Reference System for better location accuracy and services. In this study, the VRS system is investigated in terms of system principle, required H/W and S/W, management and operation, revision of related law, expected application and market etc. and find optimal solution in each aspect for economic and fast set up of the system in this country. The analysis of Korean CORS, communication infra and market estimation is performed for the efficient system establishment. Also. the suggestion on the advertisement and education of the system is also included. It is expected that this study contributes for the establishment of effective and precise nationwide location service so that many SOC areas including navigation, GIS, Telematics, LBS can provides better service for the users.