engleski

CGPS Station collocated at Split tide gauge (Croatia)

In this abstract we describe collocation of tide gauge with CGPS station in Split, Croatia. The work is carried out in the frame of Work package 2 (Absolute sea level variations) and Work package 4 (Improving the sea level observing system ; Task 4.3 - Co-location of Tide Gauge Stations with GPS) within the ESEAS-RI project. Split tide gauge is located in the town's port, on a small peer near Harbour-Master building. The TGBM (PN-165) was installed on the Master's building, which had been erected on the bedrock near a city center. There is also an auxiliary benchmark (R-1) on the tide gauge edifice. Historical precise leveling that took place during last 50 years did not show any significant changes in height between Harbour-Master's TGBM and tide-gauge auxiliary benchmark. It is also important to emphasize that during CROREF96-CRODYN96 GPS campaign new benchmark was established on the concrete roof of the tide gauge, and precise leveling was done. This benchmark was used to determine the height of Antenna Reference Point (ARP) above the national datum. Ashtech Micro-Z CGRS receiver with Dorne-Margolin antenna was an optimal choice for our tide gauge, which is installed in the tide gauge building powered by batteries and equipped with GSM modem for communication with the instrument and downloading the data. CGPS station was installed on 5 May 2004, and daily files (station name SPLT) are available starting from 6 May 2004 (day 126). Batteries are being replaced on weekly basis, and RINEX files obtained from the instruments are compressed using Hatanaka compression software, version 2.4. Preliminary analysis of the data showed that: - the number of measurements and the number of outliers is normal, - the mean residual for the code measurements is very good, - the mean residual for the phase measurements is acceptable. Knowing that the local geodetic network is very stable over the last 50 years the site chosen for locating CGPS antenna is very good and the data obtained by the CGPS station we hope will be substantial for the long-term analysis of the vertical land movements in this region.

Continuous GPS station; vertical crustal movements

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