Determination of seabed heights in the area of Polish territorial waters in the official reference system

The determination of the height in the vertical reference frame in force in Poland is based both on national regulations (Council of Ministers Regulation, 2012) and on the resolution adopted by the EUREF subcommittee in Tromsø (Resolution No. 5, EUREF Symposium, 2000). Currently, the PL-KRON86-NH vertical reference frame is in use in Poland – a normal height system referred to a quasi-geoid of the average level of the Baltic Sea determined by the zero level of the mareograph in Kronstadt. According to the Regulation, by the end of 2019, Poland will adopt the PL-EVRF2007-NH vertical reference frame, i.e. a normal height system referred to the zero level of the mareograph in Amsterdam. The authors present a method of determining normal heights of seabed referred to the zero level of the mareograph in Amsterdam for coastal areas of the Baltic Sea. This method uses GNSS measurements, the EGM 2008 model and depth measuring methods typical for underwater mining.