• Journal of Industrial Technology
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• v.36
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• pp.71-76
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• 2016

In this study, we determined the precise coordinates of TBMs (Tidal Bench Marks), which used as the national reference points in coastal area of Korea, using a GPS data analysis SW for the academic and scientific applications, GAMIT/GLOBK. For accurate 3-D positioning of TBM locations, we performed the GPS point surveying according to the national surveying policy and also acquired the GPS data for 48 TBMs located in the western and southern coastal part of Korea. Considering the results of baseline analysis to each observation session obtained from GAMIT module, the baseline analysis was realized to be done precisely because the values of Normalized RMS (NRMS) were mostly less than ${\pm}0.20mm$. Before the network adjustment using GLOBK module, we evaluated the suitability of observations for each session by applying the chi-squared test (${\chi}^2$ test) to the degree of freedom in observed session. An overall distributions of ${\chi}^2$ test were less than 1.0 for all sessions, and the statistical of ${\chi}^2$ test showed the average, 0.267 with minimum and maximum value, 0.063 and 0.653, respectively. Finally, we analyzed the network adjustment for 48 TBMs to reduce the residuals of baseline analysis on each point by connecting with 42 permanent GPS stations in Korea. In the network adjustment procedure, we set up the weighted values of each permanent station to be allocated between 0.9 and 1.14, and also removed the observed points having residual exceeds 4-times of standard deviation ($4{\sigma}$).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.1
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• pp.29-39
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• 1997

The need of transformation parameters from local geodetic datums to a geocentric coordinate system is becoming more common, with the increasing application of satellite positioning techniques to LIS/GIS survey with cadastral management. In this paper, the national transformation parameters between the Korean geodetic coordinates which is based on the Bessel 1841 ellipsoid and the WGS84 ellipsoid are determined by the least square methods with weighted parameter constraints. Three-dimensional geocentric coordinates are based on GPS observation at 31 stations in the geodetic network, the datum parameters are computed within a standard deviation of less than 1 meter. In South Korea, the national transformation parameters with Bessel geoid-heights are useful for GPS baseline processing and for middle-scale map/database transformation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.6
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• pp.645-653
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• 2010

In this study, IGS(International GNSS Service) stations were processed by the method of PPP(Precise Point Positioning), and velocities of crustal movements about the region of the Korean Peninsula were calculated precisely. The characteristics of crustal movements around Korean Peninsula were understood by velocity calculation of crustal movements. We confirmed from the result which calculated by crustal movement velocity shows the movement Eurasia and North America plate move to south-east, and Philippine plate moves to north-west. This result is respected to be utilized as a basic data about analysis of earthquake and earth physics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2390-2395
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• 2012

Monitoring of crustal movement by earthquake is an important line of study in geophysics and geodesy. In this Study, before and after the earthquake data about nine IGS permanent stations were processed by Precise Positioning System to analysis the influence area about Japanese earthquake in March 11 at 2:46pm. As the result of crustal deformation monitoring, the quantitative earthquake displacement and change of crustal movement was presented. Crustal movement monitoring using continuous GPS data processing is necessary for crustal research and predicting earthquake because crustal movement assumed a new aspect before and after the earthquake in Japan.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.1
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• pp.131-139
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• 1994

In this study, calculate the detailed geoidal undulations in and around the Korean peninsula by analysing various sources of gravity data. The relative geoidal undulations reach up to 1.5 meters in and around the Korean peninsula. Geoidal undulations in the Korean peninsula vary from 15.5 m to 30.0 m refer to GRS1980 ellisoid and show a general tendency of eastward increase. These results must be compared with results of other method, especially by the results of GPS survey.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.3
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• pp.31-39
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• 2015

This paper presents the static and kinematic positioning accuracy by the real-time GPS positioning modes of the low-cost GPS receivers using NTRIP-based augmentation service. For this, acquires both the raw measurements data of the field tests by LEA 6T GPS module of u-blox AG, and correction communication via NTRIP caster with RTKLIB as an open source program for GNSS solution. With computing the positions of the check points and road tracks by six kinds of GPS positioning modes which are Single, SBAS, DGPS, PPP, RTK, and TCP/IP_RTK, compared these results to the reference position of the check points. The position error average and rmse of the static test by GPS L1 RTK surveying showed $N=0.002m{\pm}0.001m$, $E=0.004m{\pm}0.001m$ in horizontal plane, and $h=-0.116m{\pm}0.003m$ in vertical, these results are very closed to the coordinates with the geodetic receiver. Especially, in case of the kinematic test with obstacles located on both sides of road, the computed track with ambiguity fixing showed very similar trajectory considerably from VRS network RTK mode. And also, evaluate and verify the performance of the TCP/IP_RTK mode developed based on TCP/IP protocol.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.3 s.26
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• pp.23-34
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• 2003

Currently, the efficiency of GPS has been increased in the various precise survey like as the control survey and the navigation etc. Also, it is widely used in the deformation analysis of the structure, the measurement of the marine tides, the measurement of the river level and the topographic monitoring of seabed or riverbed by combined the measurement equipment for depth. In this study, we intend to increase in efficiency of the topographic monitoring of seabed or riverbed by combined with DGPS, RTK GPS and echo sounder. For this study, we defined the error correction of the echo sounder with the experiment of water tank which is considered the characteristic of estuary riverbed and then we developed the s/w for 3-dimensional monitoring of estuary riverbed and applied the s/w to field test and improved the various problems. On analyzing topography of estuary riverbed by combined GPS with echo sounder, the draught error which is yielded to change of length from the water surface by the movement of survey vessel to the end of the transducer was eliminated by geometrical rearrangement and we defined the correction formula $z=BM+SAH-DBR_{(i)}-DRT-ED$. The sounding error about the echo sounder and characteristic of estuary riverbed was found by understanding the relation of average diameter ind residual error and we defined correction formula, $Y=0.00474{\ast}ln(X)-0.0045$ by the regression analysis. and then we verified applicability of correction formula.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.103-105
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• 2010

우리나라는 지리적 메커니즘을 고려할 때 지각판 거동에 의한 지진발생 가능성을 가지고 있으며, 최근들어 지진 횟수가 증가됨에 따라 지진에 대한 우려와 관심이 커지고 있다. 이에 본 연구에서는 지진 발생 가능성이 높은 단층지역에 위치하고 있는 양산 상시관측소로부터 수신한 GPS 자료를 정밀절대측위 방법으로 처리하고, 양산지역의 지각변동량을 계산하였다. 연구결과 양산지역은 방위각 약 $131^{\circ}$의 4cm/year 속도로 이동하고 있음을 알 수 있었으며, 이러한 결과는 양산단층지역에 대한 지구 물리 해석의 기초자료로 활용이 가능할 것으로 기대된다.

• Korean Journal of Remote Sensing
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• v.29 no.5
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• pp.545-554
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• 2013

Augustine is an active stratovolcano located in southwest of Cook Inlet, about 290 kilometers southwest of Anchorage, Alaska. Between January 11 and 28, 2006, the volcano erupted explosively 14 times. We collected twelve permanent GPS stations operating by Plate Boundary Observatory (PBO) from 2005 to 2011. All data processing was carried out using Bernese GPS Software V5.0 with IGS precise orbit. Static baseline processing by fixing AC59 station was applied for the volcano activity monitoring. AC59 is the nearest (about 24.5 km) station to Augustine volcano, and located on North America Plate including Augustine Island. The test results show inflation (9.7 cm/yr) and deflation (-9.2 cm/yr) of volcano before and after eruption around crater clearly. After volcano activity has reached a plateau, some of the GPS stations installed north of the volcano show ground subsidence phenomenon caused by compaction of pyroclastic flows. These results indicate the possibility of using surface deformation observed by GPS for monitoring and prediction of volcano activity.

• Journal of Astronomy and Space Sciences
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• v.23 no.4
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• pp.345-354
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• 2006

Korean Peninsula has been postulated to be on the Eurasian plate(EU). On the other hand, recent seismological works and GPS researches suggest that it is on a separate plate called the Amurian plate (AM). However, the GPS results we inconsistent with each other beyond the estimated statistical errors. Moreover, the estimated plate motion parameter, which we obtained from the velocity data of six Korean GPS stations, was not well agreeing with any existing results. Therefore, independent measurements are required to distinguish those results. In near future, we will have 4 VLBI stations in Korea. This compact Korean VLBI array is capable of achieving good determination of the plate motion parameters if it is located on stable sites. We estimated the precision of the AM motion parameters with the Korean VLBT array. The results showed that the Korean VLBI array would verify the existence of the AM, as far as the observation precision of 0.2-0.5mm/yr for station velocities is achieved. Therefore, new Korean geodetic VLBI array can contribute to crustal deformation studies in East Asia.