Schenk et al., 2002. New permanent GPS observatories SNEC and BISK Acta Montana 20 (124), 41-44.
NEW PERMANENT GPS OBSERVATORIES SNĚŽKA (SNEZ) AND BISKUPSKÁ KUPA (BISK) Vladimír SCHENK1), Pavel KOTTNAUER1), Zdeňka SCHENKOVÁ1), Aleš RUCKÝ2), Jiří PŠENIČKA2) and Josef ŘEHÁK Jr.3) 1)
Institute of Rock Structure and Mechanics, Academy of Sciences, V Holešovičkách 41, CZ - 182 09 Praha 8, Czech Republic,
[email protected]
2)
GEOVAP, Čechovo nábřeží 1790, CZ - 530 03 Pardubice, Czech Republic,
[email protected]
3)
Řehák-SPELEO, Pešinova 149, CZ - 500 08 Hradec Králové, Czech Republic,
[email protected]
ABSTRACT: In 2001 the Institute of Rock Structure and Mechanics bought GPS receivers Ashtech Z-18 equipped with choke-ring antennas to establish two GPS observatories inside the area of geodynamic networks “EAST SUDETEN” and “WEST SUDETEN”. EAST SUDETEN network was built in 1997, WEST SUDETEN network in 2001. For the permanent monitoring of NAVSTAR and GLONASS satellite signals two sites were tested and finally adopted: (a) a top of the highest mount of the Krkonoše Mts. Sněžka (1602 m) and (b) a top of the mount Biskupská kupa (888 m) near Silesian town Zlaté Hory. The observatories SNEZ and BISK started to operate in the summer 2001. Ashtech Z-18 receivers are connected to a standard PC equipped with a capable HD to store a great amount of observed data. Monitored data are regularly put to the HD in hourly intervals in binary and RINEX forms. When GPS day is terminated and all hourly binary and RINEX files were successfully stored, the standard Ashtech software closes them and creates one-day binary and RINEX files. To protect the receivers and the PCs against a power failure they are powered by 230V AC/ 12V DC power source/charger and backed up by 12V/220Ah batteries. The observatories operate without operators and approximately once per two months stored data are saved to external media. KEY-WORDS: GPS observatories, geodynamics, Sudeten area (the Bohemian Massif) 1. INTRODUCTION An idea to establish two permanent GPS observatories on the Sněžka Mt. and on the Biskupská kupa Mt. arose from the necessity to improve data processing of annual GPS campaigns on geodynamic networks EAST SUDETEN (Schenk et. al., 2002a) and WEST SUDETEN (Schenk et al. 2002b, Makolski et al. 2002) covering relatively large territory along the Czech-Polish border. The Czech part of these networks contemporary includes eleven sites in north-eastern Bohemia and twelve sites in northern Moravia and Silesia. Its length is round 250 kilometres and its width 100 kilometres. On the network EAST SUDETEN five annual 48 hours GPS campaigns have been organized and on the network WEST SUDETEN one. Because of a limited number of available receivers Ashtech GPS campaigns cannot pass simultaneously on both networks. Monitoring of GPS signals on the
Schenk et al., 2002. New permanent GPS observatories SNEC and BISK Acta Montana 20 (124), 41-44.
network EAST SUDETEN is postponed on two weeks. Since one observatory is always situated in one network, data monitored on the permanent station can be included to a campaign data set. Then the recent accuracy of calculated outputs of these data will still increase. Consequently, geodynamic interpretations of the GPS data would be improved and existing regional geodynamical movements in the Sudeten area better understood and explained. 2. SITING AND TECHNICAL PARAMETERS OF OBSERVATORIES SNEZ AND BISK General conditions for permanent GPS observatory siting are identical with conditions adopted for the regional network sites (Schenk et al. 2002a, 2002b) and were extended for the following items: • Availability of power source 230V AC, • Reasonable protection against tampering and theft of the GPS antenna and • Lockable place for measuring equipment (receiver, PC, power source/charger and battery, etc.). Figure 1 shows positions of observatories SNEZ and BISK with respect to neighbouring permanent GPS observatories.
Fig. 1 Observatories SNEZ and BISK and their neighbouring GPS permanent stations Technical parameters of both observatories are more or less identical and can be summarized in this way: • GPS receiver Ashtech Z-18 equipped with antenna Ashtech choke ring, • Computer PC Pentium, operating system Windows 95,
Schenk et al., 2002. New permanent GPS observatories SNEC and BISK Acta Montana 20 (124), 41-44.
• •
All equipments are powered by 230 / 12 V power source / charger and backed up by 12 V / 220 Ah lead-acid battery, Monitored GPS data are stored to hard disk and periodically saved to external media (e.g. 1 GB JAZ disks)
3. PERMANENT GPS OBSERVATORY SNEZKA The Sněžka Mt. (1602 m over the sea level) is the highest mountain of the Czech Republic. The GPS equipment is located in a small building seasonally opened that is placed near the stone geodetic pillar established in 1826 as a fundamental geodetic point of the Austrian-Hungarian monarchy. The observatory SNEZ started its operation with the GPS receiver Ashtech Z-18 and the choke-ring antenna on August 23, 2001. The antenna situated on the top of 8 m high geodetic pillar (Fig. 2a) was connected with the receiver by outdoor line fixed to 2 mm steel rope (Fig. 2b). The GPS receiver, computer and other equipment parts were located in a garret (Fig. 2c) of the small building.
a)
c)
b)
d) Fig. 2. The permanent GPS observatory SNEZ
In mid October due to a temperature decrease towards 0ºC and a possible origin of hoarfrost on the cable the antenna had to be removed and placed on the top of the chimney of small building (Fig. 2d) that was not used for the last years. This chimney was reinforced and filled by a concrete and by this way rather well stabilized site was obtained.
Schenk et al., 2002. New permanent GPS observatories SNEC and BISK Acta Montana 20 (124), 41-44.
NAVSTAR and GLONASS satellite signals are monitored with a sampling rate of 30 seconds. Binary data are directly stored to a hard disk of the PC computer and immediately transferred into the RINEX format needed for further GPS data processing. Every hour they are put together and when one-day monitoring terminates, 24 one-hour files are joined to oneGPS day file. About once per two months stored data are saved to external media (e.g. 1 GB JAZ disks). 4. PERMANENT GPS OBSERVATORY BISKUPSKÁ KUPA The Biskupská kupa Mt. (888 m over the sea level) is situated at the Czech-Polish border near town Zlaté Hory in Silesia and from the geodetic viewpoint belongs to significant Laplace points. The permanent GPS observatory BISK was placed on a stone 19.3 m high watchtower built on the top of this mount in 1898 (Fig. 3a). Equipments of the observatory (receiver Ashtech Z-18 and computer) are inside the tower and GPS choke-ring antenna was fixed on a concrete pillar on walkway of the watchtower (Fig. 3b). The GPS observatory BISK started its operation on September 6, 2001. The monitoring procedure of the GPS satellite signals is the same as it was described for the observatory SNEZ. In future it is assumed to equip the observatory BISK with permanent registration of meteorological data: temperature, humidity, pressure and wind (speed and direction).
a) b) Fig. 3. The permanent GPS observatory BISK 5. CONCLUSION Monitored GPS data will be processed by software Bernese 4.2. For future it is planned to reequip both observatories by remote control and data download. The observatory BISK could be connected via wireless Internet and the observatory SNEZ via telephone line and modem. Monitored data on both observatories form a valuable database that will improve a geodynamic research of the north-eastern part of the Bohemian Massif and will contribute to a solution of fundamental geodetic tasks.
Schenk et al., 2002. New permanent GPS observatories SNEC and BISK Acta Montana 20 (124), 41-44.
Acknowledgement: The establishment of the GPS observatories and their operation were supported by the Ministry of Education, Youth and Sport of the Czech Republic, Project LN00A005 “Center for Earth Dynamics Research” and from funds of the Grant Agency of the Czech Republic, research project No. 205/01/0480. REFERENCES Schenk, V., Cacoń, S., Bosy, J., Kontny B., Kottnauer P. and Schenková Z. (2002a): Five years of GPS geodynamic network SUDETEN (1997-2001). Acta Montana, Series A, No. 20 Schenk, V., Schenková, Z., Kottnauer, P., Rucký, A., Pšenička, J. and Řehák, J. Jr. (2002b): GPS regional network “WEST SUDETEN” – A westward wide-ranging extension of present “EAST SUDETEN” network. Acta Montana, Series A, No. 20 Makolski, K., Mierzejewski, M. and Kaczalek, M. (2002): Geodynamic research concerning recent movements in the Karkonsze Mts. and Karkonosze foreland. Acta Montana, Series A, No. 20
NOVÉ OBSERVATOŘE GPS SNĚŽKA (SNEZ) A BISKUPSKÁ KUPA (BISK) Vladimír SCHENK1), Pavel KOTTNAUER1), Zdeňka SCHENKOVÁ1), Aleš RUCKÝ2), Jiří PŠENIČKA2) a Josef ŘEHÁK Jr.3) V roce 2001 Ústav struktury a mechaniky hornin, Akademie věd ČR, zakoupil příjímače GPS Ashtech Z-18 vybavené anténami choke-ring k vybudování dvou observatoří GPS v oblastech geodynamických sítí “VÝCHODNÍ SUDETY” a “ZÁPADNÍ SUDETY”. Síť VÝCHODNÍ SUDETY byla vybudována v roce 1997, síť ZÁPADNÍ SUDETY až v roce 2001. Obě místa byla na příjem satelitních signálů NAVSTAR a GLONASS testována a a závěrem doporučena: (a) vrchol Sněžky (1602 m), nejvyšší hory Krkonoš, a (b) vrchol hory Biskupská kupa (888 m) ležící blízko města Zlaté Hory. Provoz na observatořích byl zahájen v létě 2001. Přijímače Ashtech Z-18 jsou připojeny ke standardnímu osobnímu počítači vybavenému dostatečným pevným diskem k ukládání velkého množství observatorních dat. Monitorovaná data jsou na tento disk pravidelně v jednohodinových intervalech ukládána jak v binárním tak i RINEXovém formátu. Když proběhne celý GPS den a všechny jednohodinové binární i RINEXové soubory byly úspěšně uloženy, standardní software firmy Ashtech je spojí dohromady a vytvoří celodenní binární a RINEXové soubory. K zajištění bezporuchového chodu přijímače signálů GPS a registračního počítače jsou tato zařízení napájena přes měnič elektrického proudu 230V AC/ 12V DC na který je připojena vysokokapacitní baterie 12V/220Ah k napájení zařízení v případě výpadku elektrického proudu. Obě observatoře pracují bez operátora a cca jednou za dva měsíce jsou datové soubory z pevného disku stahovány na externí datová média.
