Ship Gravimetry Activities on the Baltics within the Framework of the FAMOS Project

Abstract:

FAMOS (Finalising Surveys for the Baltic Motorways of the Sea) was a project started in 2014 and which was supported by the European Union to improve the safety of ship navigation on the Baltic Sea. One task of this project was working on a common height reference for the Baltic Sea, the so-called Baltic Sea Chart Datum 2000 (BSCD2000), which will be based on a new gravimetric geoid. The German institutions GFZ, BKG, BSH and TU Darmstadt performed several ship gravimetry surveys to contribute to this project.

The primary equipment used in these activities was GFZ’s Chekan-AM gravimeter. In addition, on two of these campaigns an iMAR strapdown gravimeter was used together with the Chekan-AM. The data records from both instruments are of very good consistency and combination of both data types might enable enhanced results with complete and reliable short-wavelength results and also a high long-wavelength stability. Furthermore, it can be expected that the strapdown measurements enables filling data gaps in the Chekan recordings e.g. during disturbed turning periods. On the other hand, the Chekan measurements show a higher long-time drift stability compared to that of the strapdown instrument and can help improving the drift estimation of the strapdown gravimeter during longer campains.

Since the FAMOS project ended prior to the planned schedule already in 2019, finalisation of the new height reference for the Baltics is now coordinated by the Chart Datum Working Group (CDWG) within the Baltic Sea Hydrographic Commission (BSHC). It is planned to implement the new chart datum, BSCD2000 by 2023.