TY - JOUR N2 - Research activities of Polish research groups in a period of 2015–2019 on reference frames and reference networks are reviewed and summarised in this paper. The summary contains the results concerning the implementation of latest resolutions on reference systems of the International Union of Geodesy and Geophysics and the International Union of Astronomy with special emphasis on the changes in the Astronomical Almanac of the Institute of Geodesy and Cartography, Warsaw. It further presents the status of the implementation of the European Terrestrial Reference System 1989 (ETRS89) in Poland, monitoring the terrestrial reference frame, operational work of GNSS permanent IGS/EPN stations in Poland, operational work of the laser ranging station in Poland of the International Laser Ranging Service (ILRS), active GNSS station network for the realization of ETRS89 in Poland, validation of recent ETRS89 realization, expressed in ETRF2000 in Poland, and maintenance of the vertical control in Poland (PL-KRON86-NH). Extensive research activities are observed in the field of maintenance and modernization of gravity control not only in Poland, but also in Sweden and in Denmark, as well as establishment of gravity control in Ireland based on absolute gravity survey. The magnetic control in Poland was also regularly maintained. The bibliography of the related works is given in references. L1 - http://journals.pan.pl/Content/110006/PDF/01_geodesy_1_2019_2k.pdf L2 - http://journals.pan.pl/Content/110006 PY - 2019 IS - No 1 EP - 29 DO - 10.24425/gac.2019.126093 KW - reference system KW - reference frame KW - vertical control KW - gravity control KW - magnetic control A1 - Krynski, Jan A1 - Rogowski, Jerzy B. A1 - Liwosz, Tomasz PB - Commitee on Geodesy PAS VL - vol. 68 DA - 2019.05.30 T1 - Research on reference frames and reference networks in Poland in 2015–2018 SP - 5 UR - http://journals.pan.pl/dlibra/publication/edition/110006 T2 - Geodesy and Cartography ER -