As a result of more than 5 years of research and development activities a
permanent GPS station has been established at the Department of Geodesy and
Surveying at the Budapest University of Technology and Economics (BUTE). This
station is the second one in Hungary, the first one is operated by the
Satellite Geodetic Observatory of the Institute for Surveying and Remote
Sensing since 1996 (Borza-Kenyeres, 1995;  Kenyeres-Borza, 1997;
Kenyeres,
1999). According to our plans we would like to use the data provided by this
station in the field of R &amp; D and the education as well as in the solution
of other projects related to these topics

Rózsa, Szabolcs

Szűcs, László

Tokos, Tamás

Ádám, József

English

Periodica Polytechnica (Budapest University of Technology and Economics)

PERIODICA POLYTECHNICA SER. CIV. ENG. VOL. 46, NO. 2, PP. 179–184(2002)ESTABLISHMENT OF A PERMANENT GPS STATION AT THEDEPARTMENT OF GEODESY AND SURVEYING OF THEBUDAPEST UNIVERSITY OF TECHNOLOGY AND ECONOMICSJózsef ÁDÁM , László SZŰCS, Tamás TOKOS and Szabolcs RÓZSAMTA-BME Research Group for Physical Geodesy and GeodynamicsDepartment of Geodesy and SurveyingBudapest University of Technology and EconomicsH–1521 Budapest, HungaryReceived: Jan. 25, 2002AbstractAs a result of more than 5 years of research and development activities a permanent GPS stationhas been established at the Department of Geodesy and Surveying at the Budapest University ofTechnology and Economics (BUTE). This station is the second one in Hungary, the first one isoperated by the Satellite Geodetic Observatory of the Institute for Surveying and Remote Sensingsince 1996 (BORZA–KENYERES, 1995; KENYERES–BORZA, 1997; KENYERES, 1999). Accordingto our plans we would like to use the data provided by this station in the field of R&D and the educationas well as in the solution of other projects related to these topics.Keywords:permanent GPS station, co-ordinate determination.1. The Structure and Operation of the Permanent Station1.1. The Structure of the Permanent StationThe permanent GPS station (Fig. 1) consists of:• a dual frequency GPS receiver (4700 TS),• a dual frequency GPS antenna (Trimble Microcentered L1/L2 with ground-plane and weather dome) (Fig. 2),• permanent station software (Trimble TRS v 1.01),• a computer,• a UPS.The role of the antenna and the receiver needs no explanation. The ground-plane helps preventing the effect of multipath; the weather dome protects the an-tenna. After the measurement of the antenna position is completed, it is not possibleto remove the weather dome, because it changes the position of the phase centre.The UPS makes the data collection possible in case of power cut (Fig.1).The key part of the station is the TRS software, which controls the receiverand stores the data. It has two parts; a resident part and the user interface. Theresident part collects and stores the data. This part must always be running. The180 J. ÁDÁM et al.user interface is for controlling the station, this part should not always run. Thesoftware can collect several types of data at the same time. The usual parametersfor geodetic purposes: 15 degrees elevation mask, 15 sec. integration time, 1-hourrollover. The software uses the GPS time. The data files can be produced in zip,gzip or self-extracting exe format. It is possible the remote control of the stationthrough the Internet, but for security reasons we do not recommend it.The data can be stored locally, or can be sent automatically to another com-puter. This is the safer choice, because the users do not contact directly the datacollector computer. They can download the needed files through the web or viaFTP using their own login name and password from a server.G PS A nte nnaTrim b le  4700 TSG PSta tio n Sta rG a teUPS220 VD a taFig. 1. The structure of the permanent stationFig. 2. The permanent antenna on the roofESTABLISHMENT OF A PERMANENT GPS STATION 1811.2. The Determination of the Position of the AntennaOne of the most important tasks in the process of establishing the permanent GPSstation was to mount correctly the antenna onto a suitable place and to determineits position.The antenna has been mounted onto the top of the roof of the southern wing ofthe central building of BUTE. We carried out the GPS measurements for determiningthe precise position of the antenna between 22nd and 24th of July 2000. We haveused the network shown inFig. 3 for the measurements. In this network onlythe position of the new permanent station (BUTE) is unknown, the other stationshad ETRS89 co-ordinates. Most of the known points are also the members of theHungarian GPS Network for Deformation Analysis, these are: PENC, SASHEGY(BUDA), NADAP; and we also have used the station PILIS, although there is noforce-centered point, therefore we could mount the antenna by tripod. This networkhas the following advantages:a) the stations in the deformation analysis networkare re-measured in every two years, therefore their motion can be detected and takeninto account in the positioning process, andb) when an error occurs with any of thereceivers during the campaign, the position of the antenna can be determined usingthe other points without any problems.PencPilisNadapSashegyBUTEFig. 3. Determination of the permanent station’s positionThe measurements were postprocessed by two different softwares and twodifferent users. The softwares were: GPSurvey 2.35 and Trimble Geomatics Office.The co-ordinates coming from the two solutions agreed in the level of 2–3 mm,therefore we can neglect the effect of personal or software failures. The ellipsoidal(geodetic) co-ordinates and their mean errors of the phase centre of the permanentstation in ETRS89 using the GRS80 geocentric ellipsoid as a reference are the182 J. ÁDÁM et al.following (TOKOS, 2001):ϕ = 47◦ 28′ 51.39721′′ (mϕ = ±0.001 m)λ = 19◦ 03′ 23.50588′′ (mλ = ±0.001 m)h = 180.924 m (mh = ±0.008 m).In order to control the position of the antenna we have established a monitoringnetwork (Fig. 4), which is going to be re-measured in every year.Fig. 4. The monitoring network1.3. The Operation and the Access of the Permanent StationThe results of the measurements are stored automatically by a computer, whichis maintained only for this purpose. We store the data in two file formats. Thefirst is the Trimble DAT format, while the other is the RINEX 2.1 format. RINEX2.1 is available for those customers, who have different GPS receivers than Trim-ble. The logging interval is 6 hours. After the closure the data files are mirroredonto a server, in a way that the data files are available on the Internet, and can bedownloaded by a standard web browser. The URL of the permanent station is:http://stargate.fgt.bme.hu.The separate WEB server enables us to defend the permanent station fromattacks from the Internet, and the same time it provides a second storage for safetyreasons. In every 3 months the stored data are backed up on CD-ROMs.2. The Utilisation of the Permanent StationIn Hungary many universities and colleges have GPS receivers, but due to financialreasons, the number of GPS receivers is low. The permanent station enables themESTABLISHMENT OF A PERMANENT GPS STATION 183to use their equipment more efficiently within the frame of education or research,because they do not need to use a receiver as a base receiver.The planned active GPS network (Fig. 5) (BORZA, 2000) does not allow touse one-frequency receivers in the area of Budapest, because the closest stationsare not within the distance of 15 km. Due to the fact, that more than half of theenterprises having GPS receivers are based in Budapest, and most of them use one-frequency receivers, they will be able to use the data provided by our station, andin a way that they can enhance their productivity.Fig. 5. The planned active GPS network of HungaryOn the other hand with the application of the permanent station, our customerscan determine the position of points in the ETRS89, which decreases the chances ofmistakes in the postprocessing. We cannot neglect the fact, that those enterprises,which have two-frequency receivers, can use the data of both permanent stations,and in a way, that they can decrease the effect of technical failures on the side ofthe permanent stations.Therefore, we think that our permanent station should be included in thenational network, because it provides a very good coverage in the area of Budapest.2.1. The Further Enhancement of the Permanent StationFor the continuous and safe operation a 12-channel GPS receiver should be pur-chased. This device can log the data from more satellites than the current receivercan, which is necessary for our users too.On the other hand, we plan to broadcast real time corrections via radio.184 J. ÁDÁM et al.We have to enhance our IT equipment as well, because we need to have asecond computer for data logging in case of a problem, and when the number ofour users increases, our web server must be enhanced to meet the requirements ofour customers.3. SummaryThe established permanent GPS station has a wide variety of ways of application.The data provided by the station can support not only the education, but also theresearch in the fields of geodesy, geophysics, meteorology, navigation, GIS andmapping.We plan to enhance our current system and broadcast real-time corrections inthe future.The normal operation of our permanent station began on 1st f February 2001.The stored data are available on the Internet, and they can be downloaded.AcknowledgementsThe financial background of development and establishment of the permanent station wasprovided by the Ministry of Transport and Water, the Hungarian Space Office under theproject KöViM/MŰI TP 22 (‘The Establishment of a Feasibility Study for Real-time Geo-metric Data Service of GPS Information Systems for Scientific and Commercial Purposes’,project leader: Dr. Péter Biró) and the project TP 140 (‘The Preparation for the Establish-ment of a GPS Permanent Station (2000)’ project leader: Dr. József Ádám), the Broad-casting Fund of Ministry of Transport and Water, the Hungarian Scientific Research Fund(under project OTKA M028208) and the Foundation ‘Industry for the Modern Educationof Engineers’ of the BUTE.References[1] BORZA, T. – KENYERES, A., On the Applicaton of Differential GPS Technique (in Hungarian),Geodézia és Kartográfia, 48 No. 11 (1995), pp. 15–21.[2] K ENYERES, A. – BORZA, T., The First Hungarian Permanent Station: PENC, (in Hungarian),A 11. Kozmikus Geodéziai Szeminárium el˝oadásainak gy˝ujteményes kötete, MHTÉHI, Budapest,(1997), pp. 100–112.[3] K ENYERES, A., Permanent Station(s) in the Hungarian Geodetic Practice, (in Hungarian),Geo-matikai Közlemények I., Sopron, (1999), pp. 43–48.[4] TOKOS, T., The Establishment of a Permanent GPS Station, (Diploma Thesis in Hungarian),Budapest, 2001.[5] BORZA, T., The Actual Topics of the Establishment and Maintenance of the Hungarian ActiveGPS-Network, (in Hungarian),Geodézia és Kartográfia, 52 No. 9 (2000), pp. 21–27.

ESTABLISHMENT OF A PERMANENT GPS STATION AT THE DEPARTMENT OF GEODESY AND SURVEYING OF THE BUDAPEST UNIVERSITY OF TECHNOLOGY AND ECONOMICS

https://pp.bme.hu/ci/article/download/630/385

ESTABLISHMENT OF A PERMANENT GPS STATION AT THE DEPARTMENT OF GEODESY AND SURVEYING OF THE BUDAPEST UNIVERSITY OF TECHNOLOGY AND ECONOMICS

Abstract

Similar works

Full text

Available Versions

Periodica Polytechnica (Budapest University of Technology and Economics)