• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.431-435
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• 2003

GPS측량 방법은 크게 나누어 후처리 방법과 실시간 처리 방법으로 구분되며 후처리 방법은 다시 Static, Stop＆Go 및 동적(Kinematic) 방법으로 세분되고 실시간 처리 방법은 DGPS(Differential GPS)와 RTK(Realtime Kinematic) 방법으로 세분된다. 이와 같은 여러 가지 측량법 중 우리나라의 실무에서는 유독 후처리 방법 중의 Static 측량과 실시간 처리방법중의 DGPS 측량이 주로 사용되어 왔는데, 그런 배경에는 여러 가지 원인이 있으나 무엇보다도 가장 큰 원인은 공공측량 작업규정 등의 측량 관련 법규에서 다양한 종류의 GPS측량기법을 제도적으로 인정하지 못함으로 인하여 일반 측량기술자들의 GPS에 대한 인식이 결여된 때문이라 볼 수 있다.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.1
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• pp.84-91
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• 2007

As GPS equipments improve, one can acquire GPS data easily in the field. To obtain precise and accurate coordinates, however, post processing is additionally required and the processing needs high degree of skills. Besides, it is very common that we cannot operate processing softwares in the field because the required system environment is usually not prepared. The aim of this study is the development of an internet-based GPS data processing service. For post processing, we used GIPSY developed by JPL. It has many advantages such as obtaining coordinates quickly by using precise or predicted ephemeris. This service proceeds as following orders by interlocking GIPSY software and internet service which is operated on a Linux platform: Users upload the raw data file on the internet, then GIPSY runs automatically and then the user gets the result in the field. We use an Apache web server as the hosting program and PHP scripts are used in coding web pages. The total processing time including data-uploading was around 30 seconds for a 24-hour data with a 30-second sampling rate.

• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.60-66
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• 2010

This paper deals with a post-processing of GPS receiver data in order to acquire a reference flight trajectory of an aircraft test. The flight test using an aircraft that is carried out several times since 2007 is the integrated test to verify the performance of the tracking and communications facilities in Naro Space Center and Jeju Tracking Center. In order to analyze performance of the tracking and navigation equipments, true reference data should be used for performance comparisons. Therefore off-the-shelf commercial GPS receiver, DL-V3 made by NovAtel Inc., is operated on the test to collect the GPS navigation data and the collected data is post-processed by GrafNav which is the off-the-shelf post-processing program made by NovAtel Inc. Through the post-processing of the collected data, a reference trajectory is generated with small error range about several decade centimeter level.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.4
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• pp.251-261
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• 2003

To measure the GPS position accuracy and its distribution according to the length of the baseline, 30 minutes to 24 hours observations at the fixed location were conducted with two GPS receivers (Ll, 12 channels) on May 29 to June 2, 2002. The GPS data received at the reference station, the rover station and the ordinary times GPS observation station operated by the National Geography Institute in Korea were processed in kinematic and static post-processing methods with a post -processing software. The results obtained are summarized as follows: 1. The number of the satellite that could be observed continuously more than six hours was 16 and most of these satellites were positioned at east-west direction on May 31, 2002. The number of the satellite observed and the geometric dilution of precision (GDOP) determined by the average of every 10 minute for the day were 8 and 3.89, respectively. 2. Both the average GPS positions before and after post-processing were shifted (standalone: 1.17 m, post -processing: 0.43m) to the south and west. The twice distance root mean square (2drms) measured with standalone was 6.65m. The 2drms could be reduced to 33.8% (standard deviation 0=17.2) and 5.3% (0=2.2) of standalone by the kinematic and the static post-processing methods, respectively. 3. The relationship between the length of the baseline x (km) and the 2drms y (m) obtained by the static post-processing method was y=0.00l6x+0.006 $(R^2=0.87)$. In the case of the positioning with the static post-processing method using the GPS receiver, it was found that a positioning within 20cm 2drms was possible when the length of the baseline was less than 100km and the receiving time of the GPS is more than 30 minutes.

• Spatial Information Research
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• v.9 no.2
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• pp.309-324
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• 2001

To apply the real-time kinematic GPS surveying technique, this research has tried to obtain the TOKYO datum first from the continuous reference stations distributed all over the country. Then, analysis of the geography of a coastal area including both of land and sea has been carried out by the post-processed continuous kinematic GPS technique and the real-time kinematic GPS surveying technique. After considering the initial conditions and measuring time zone for real-time kinematic GPS, post-processed and the real-time kinematic GPS measurements have been carried out. A new system has been proposed to store measured data by using a program developed to store GPS data in real time and to monitor the satellite condition through controller simultaneously. The accuracy of GPS data acquired in real time was as good as that acquired by post processing. It is expected that it will be useful for the analysis of coastal geographic characteristics because DTM can be also constructed for the harbor reclamation, the dredging and the variation of soil movement in a river.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.499-505
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• 2004

현재 국내에서 활발히 이루어지고 있는 GPS 정밀측지측량은 획득된 GPS 관측값의 결과값이 GPS 기준점의 기하학적 강도와 분산계수의 상관관계의 연관성과의 분석없이 사용되고 있는 문제점을 파악하고 육지와 해상의 통합지리정보시스템구축을 위한 수치지도와 전자해도의 통합투영의 필요성에 의해서 이루어졌다. 본 연구의 목적은 크게 GPS 관측값의 정밀도를 향상시키는 방법과 수치지도와 전자해도의 통합투영으로 GPS 기준점들을 이용한 수치지도와 전자해도상의 경계선 오차량을 비교검토를 통해 수치지도와 전자해도의 통합관리의 방향을 제시하는데 있다. GPS 관측값의 정밀도 향상을 위한 방법제시를 위하여 GPS 망조정에 사용되는 3점의 기준점에 대한 기하학적인 강도에 따른 정밀도 분석방법과 분산계수의 변화에 따른 GPS 관측값들의 정밀도 분석방법으로 나누어 검토하였다.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.1 s.28
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• pp.55-62
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• 2004

More recently, multiple reference based RTK GPS techniques(VRS ; Virtual Reference System) are becoming increasingly important for many precise GPS applications in many countries to overcome the constrained distance limitations of standard RTK systems. The precision of the position solutions of the rover receiver is closely connected with that of the corresponding virtual reference points(VRPs). The objective of this paper is to investigate the accuracy and performance of the VRPs on the test network have been made in post mode, and the overall analysis results were presented by comparing the solutions for the VRPs from the existing GPS reference station with the true values of the coordinates used to produce the observation data. The results show the reasonable accuracies of VRPs in the network area by using the VRS concept in post mode.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.451-454
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• 2006

텔레매틱스 서비스 중 가장 중요한 서비스는 운전자가 요청하는 교통 상황 정보를 신속하고 정확하게 전달해 주는 것이다. 본 논문에서는 GPS 단말기를 장착한 차량들을 통해 수집된 자료를 활용한다. 가까운 과거의 패턴 자료를 이용하여 필터링 범위를 산정한 후, 실시간으로 비정상적인 GPS 자료를 제거하여 링크의 대표 속도 값을 산출하는 방법을 제시한다.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.1 s.19
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• pp.37-49
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• 2002

RTK-GPS(Real Time Kinematic GPS) surveying technique which allows centimeter level three-dimensional coordinates in real time has been recognized as a major advance in the science of GPS positioning. And no longer is it necessary to wait until post-processed results are computed after the surveying has been completed in field. The purpose of this study is to present the accuracy and effectiveness of the determinated parcel coordinate by RTK-GPS surveying technique, through the analysis and comparison of the surveying results both in Total Station and RTK-GPS.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.626-632
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• 2013

In this study the GPS Precipitable Water Vapor (PWV) was derived and evaluated by a radiosode measure during the winter intensive observation in Gangneung site from January 5 till February 29 in 2012. Bernise 5.0 software was used to derive the GPS data. GPS-derived PWV from Zero difference (GANG) and Single difference (GANG and DAEJ) was high variance in time and about 5 times the PWV of radiosonde. GPS post-processing has been performed from two additional IGS site (Xian Dao, Ibaraki-ken) in order to correct the absolute troposphere errors. As a result, the mean bias error (MBE) and root mean square error (RMSE) and correlation compared with radiosonde measure were 0.67 mm, 6.40 mm, and 0.93, respectively. In order to correct the relative troposphere errors from the altitudinal difference between the two GPS receivers, we calculated the GPS-derived PWV by adding the data of GPS that was installed in Gangneung-Wonju University near the Gangwon Regional Meteorological Administration. In the end, the improved result showed that MBE, RMSE and correlation in comparison with radiosonde measures were 0.61 mm, 5.79 mm, and 0.93, respectively.