Global Change Master Directory gsfc-gcmduso@mail.nasa.gov 50 2013-05-21T05:43:44Z http://mddemo.gsfc.nasa.gov/KeywordSearch/OpenSearch.do 5 0 http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]GNSS_orbits1 -180.0,-90.0,180.0,90.0 1992-01-01T00:00:00Z T00:00:00Z 2009-02-06T05:00:00Z

Global Navigation Satellite System data consists of the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS) data sets. The satellites transmit the ranging ...

http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]CDDIS_VLBI_data -180.0,-90.0,180.0,90.0 1979-01-01T00:00:00Z T00:00:00Z 2008-12-05T05:00:00Z

Very Long Baseline Interferometry (VLBI) is a geometric technique: it measures the time difference between the arrival at two Earth-based antennas of a radio wavefront emitted by a distant quasar. ...

http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]CDDIS_SLR_data -180.0,-90.0,180.0,90.0 1976-01-01T00:00:00Z T00:00:00Z 2008-12-04T05:00:00Z

In Satellite Laser Ranging (SLR), a short pulse of coherent light generated by a laser (Light Amplification by Stimulated Emission of Radiation) is transmitted in a narrow beam to illuminate corner ...

http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]CDDIS_GNSS_data -180.0,-90.0,180.0,90.0 1992-01-01T00:00:00Z T00:00:00Z 2008-12-02T05:00:00Z

Global Navigation Satellite System data consists of the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS) data sets. The Global Positioning System, ...

http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NAOMIZSGL -180.0,-90.0,180.0,90.0 1984-01-01T00:00:00Z T00:00:00Z 1997-01-13T05:00:00Z

Terrestrial and celestial reference frames and the earth rotation parameters are determined from the global geodetic VLBI observations from 1984. The data include site positions at 1988, site proper ...