The GPS Toolbox ITRF Transformations     

Jan Kouba 《GPS Solutions》2002,5(3):88-90

The GPS Toolbox is dedicated to highlighting algorithms and source code utilized by GPS engineers and scientists. If you have an interesting subroutine or program you would like to share with our readers, please pass it along so that we might continue to bring you this column; e-mail it to us at gps-toolbox@ngs.noaa.gov. To comment on any of the source code discussed here, or to leave a request for a piece of source code you may be looking for, visit our web site at http:/www.ngs.noaa.gov/gps-toolbox. This column is edited by Stephen Hilla, National Geodetic Survey, NOAA, Silver Spring, Maryland, and Mike Craymer, Geodetic Survey Division, Natural Resources Canada, Ottawa, Ontario, Canada. ? 2002 Wiley Periodicals, Inc.  相似文献   

Progress in Carrier Phase Time Transfer   总被引：1，自引：0，他引：1  

Jim Ray  Felicitas Arias  Gérard Petit  Tim Springer  Thomas Schildknecht  Jon Clarke  Jan Johansson 《GPS Solutions》2001,4(4):47-54

The progress of the joint Pilot Project for time transfer, formed by the International GPS Service (IGS) and the Bureal International des Poids et Mesures (BIPM), was recently reviewed. Three notable milestones were set. (1) The IGS will implement, at least in a test mode, an internally realized time scale based on an integration of combined frequency standards within the IGS network. This will eventually become the reference time scale for all IGS clock products (instead of the current GPS broadcast time). (2) A new procedure for combined receiver and satellite clock products will be implemented officially in November 2000. Receiver clocks are an entirely new product of the IGS. (3) The BIPM will coordinate an effort to calibrate all Ashtech Z12-T (and possibly other) receivers suitable for time transfer applications, either differentially or absolutely. Progress reports will be presented publicly in the spring 2001. ? 2001 John Wiley & Sons, Inc.  相似文献   

Determination of Geopotential Differences between Local Vertical Datums and Realization of a World Height System   总被引：2，自引：0，他引：2  

Burša  Milan  Kouba  Jan  Müller  Achim  Raděj  Karel  True  Scott A.  Vatrt  Viliam  Vojtíšková  Marie 《Studia Geophysica et Geodaetica》2001,45(2):127-132

The methodology developed for connecting Local Vertical Datums (LVD) was applied to the Australian Height Datum (AHD) and the North American Vertical Datum (NAVD88). The geopotential values at AHD and NAVD88 were computed and the corresponding vertical offset of 974 mm with rms 51 mm was obtained between the zero reference surfaces defined by AHD and NAVD88. The solution is based on the four primary geodetic parameters, the GPS/levelling sites and the geopotential model EGM96. The Global Height System (or the Major Vertical Datum) can be defined by a geoidal geopotential value used in the solution as the reference value, or by the geopotential value of the LVD, e.g. NAVD88.  相似文献   

秦岭八卦庙金矿金的矿化与铂族金属的富集   总被引：5，自引：0，他引：5       下载免费PDF全文

苏瑞侠  刘平  郭健 《地质找矿论丛》2001,16(1):12-18

文章报道了八卦庙特大型金矿床中伴生的铂族金属矿化的地质特征，岩石矿物学特征和新发现矿物－－自然（钨）钌矿的基本矿物学特征，铂族金属矿化与金矿化围岩蚀变的关系研究表明，八卦庙金矿中伴生的铂族金属富集于后期岩浆热液改造期，成矿物质主要来源于后期改造的热液，铂族金属的富集与金的富集呈明显的正消长关系，成矿的温度为140－500度，矿化深度＞3．7km，成矿流体是以中酸性岩浆热液为主的多成因热国水，矿物组成以复杂的高温硫化物，合金类为主要特征；化学成分也比较复杂，以Au,Cu,As,Ag,Ni,Co,Sb,S和铂族金属Ru,Ir,Os异常等为特点，这类伴生铂族金属的金矿床将为秦岭成矿带寻找铂族金属提供了典型实例。  相似文献   

High-speed photography of the bubble generated by an airgun1     

Jan Langhammer  Martin Landr 《Geophysical Prospecting》1996,44(1):153-172

High-speed photography has been used visually to study the shape, surface, turbulence and behaviour of an underwater oscillating bubble generated by an airgun. The source was a BOLT airgun with a chamber volume of 1.6cu.in., placed in a 0.85m³ tank at 0.5m depth. Near-field signatures were also recorded in order to compare the instant photographs of the oscillating bubble with the pressure field recorded about 25 cm from the gun. Estimations of the bubble-wall velocity and bubble radius estimated from high-speed film sequences are also presented, and are compared with modelled results. The deviation between the modelled and measured bubble radii was at most 9%. In order to check the capacity for transmission of light through the bubble, a concentrated laser beam was used as illumination. We found that the air bubble is a strong scattering medium of laser light, hence the bubble is opaque.  相似文献   

Magnetic field measurements in India during the last two centuries     

A. Janáčkova  L. Urban  M. Chmelař 《Studia Geophysica et Geodaetica》1992,36(2):151-160

Summary The direction of the geomagnetic field has changed substantially less in India than in Europe since the end of the 18th century.Whereas the European geomagnetic time series indicate a tendency of secular variation from which a remarkable westward drift of the non-axial field can be deduced, in India the field direction seems to have remained more or less fixed over the last two centuries. The drift of the non-axial field seems to be very small, or even eastward.  相似文献   

Seismic Anisotropy in the Earth     

Jan  Garmany 《Geophysical Journal International》1992,110(2):399-399

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Book reviews     

Mark S. T. Bukowinski  Philip E. Wannamaker  Manfred Koch  Yukio Fujinawa  Dr. Pradeep Talwani  D. Möhlmann  Andrew H. Knoll  Lucia Lovison-Golob  Krzysztof Haman  Hanna Pawłowska  Henryk Piwkowski  Dr. Anthony Dore  Nguyen Xuan Huy  Edward R. Cook  Jan Błecki  Jacek Leliwa-Kopystynski  Magdalena Sroczynska-Kozuchowska 《Pure and Applied Geophysics》1993,140(1):139-177

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Determination of period of oscillation and sensitivity of simple horizontal pendulums for tidal measurements     

Pícha  Jan  Skalský  Lumír 《Studia Geophysica et Geodaetica》1963,7(2):156-163

Studia Geophysica et Geodaetica - Авторы уже раньше...  相似文献   

Vergleich der Methoden Harmonischer Analyse und Einige Bemerkungen zu den Kontrollen der Berechnungen     

Jan Pícha 《Studia Geophysica et Geodaetica》1960,4(1):85-93

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