[IGSSTATION-5590] ZIM2/ZIM3: displacement of the marker by about 5 mm horizontally

[Brockmann Elmar swisstopo]

Author: E. Brockmann

Dear colleagues,

On October 10, 2013 (DOY 283) a new dome was mounted on the neighbouring building to the ZIM2/ZIM3 mast. Unfortunately, the crane (weight of 60 t) stabilized itself much too close to the fundaments of the ZIM2/ZIM3 mast.

The result is a south-west jump of the mast of roughly 5 mm (equally distributed to the north and west component, no effect vertically). The results are identical for ZIM3 (antenna splitting to the same antenna). The jump is much more difficult to see from standard network solutions using the ionosphere-free linear combination L3 and troposphere estimates after 2 weeks - but will certainly be visible after another half of year of data processing.

More details can be found on http://www.swisstopo.admin.ch/swisstopo/geodesy/pnac/presentations/Factsheet_Zimmerwald_2013_10_10.pdf


swisstopo promotes since 2007, when the Swiss permanent network was enhanced to GPS/GLONASS, to operate double stations on important stations. Twin stations monitor each other on a much higher level of accuracy as it is possible for stations which are integrated in networks with larger station separation. Unfortunately, this actual event demonstrates the potential of twin station monitoring from point of precision and alert time.

Nevertheless, the time series is interrupted due to this event. This weakens the velocity estimation considerably.
Due to the order of magnitude of the discontinuity we decided to keep the ZIM2/ZIM3 names and not to distribute the data under new names ZIM4/ZIM4. Station logfiles will soon be updated.

Sorry for any inconveniences this may have caused.
Best regards,
Elmar Brockmann


Elmar Brockmann
swisstopo
Federal Office of Topography
Geodesy
Seftigenstrasse 264
CH-3084 Wabern
Phone   +41 31 963 21 11        operator
        +41 31 963 22 56        direct
Fax     +41 31 963 24 59
elmar.brockmann at swisstopo.ch
www.swisstopo.ch