History of GPS observations

29 April 1995
after some experimentation, continuous registration of data to computer began

14 May 1995
first dataset sent to data center OLG, Graz, Austria

28 June 1995
started automatic data sending via connection of on-site computer to Internet

3 September 1995
data from GOPE are used in the analytical center CODE, Bern, Switzerland to precise orbit determination

11 - 19 June 1997
defect of Trimble receiver, during the reparation measurements were performed by Geotracer 100 receiver

17 November 1998
hourly data started to be sent to data center OLG

4 November 1999
the Trimble 4000SSE receiver with antenna replaced by Ashtech Z18 receiver with Ashtech Choke Ring GG antenna, equipped by protecting radome; observations of GLONASS satellites started, data from both GPS NAVSTAR and GLONASS are sent to the regional data center BKG, Frankfurt Am Main, Germany, together with a meteorological data

24 July 2000 - 4 october 2000
defect of the Ashtech Ashtech Z18 receiver; the reciver as well as its antenna sent to manufacturer; meantime measured by Trimble 4000SSE with Trimble antenna. After repair, a new antenna Ashtech Choke Ring received and employed.

20 June 2001
data for LEO pilot project begin to send to the global data center CDDIS, GSFC, NASA, Maryland, USA (for processing of data from low-earth orbiting satellites).

3 July 2002
the sending of data with GPS NAVSTAR measurements only ended; the data with both GPS NAVSTAR and GLONASS measurements in hourly and daily files is sent since this day (to both data centers - OLG and BKG).