Jaroslav Klokočník (*1948 in Prague) is an emeritus professor and research worker in the field of space geodesy, satellite dynamics and geodynamics. He has published over 220 research papers and is the author or co-author of five books and of three class texts. He studied geodesy and cartography at the Faculty of Civil Engineering, Czech Technical University in Prague. He obtained his master‘s degree in 1971. Since 1972 we works at the Astronomical Institute, Czech Academy of Sciences, Ondřejov Observatory, where he defended PhD for astronomy in 1979 and DrSc for astronomy in 1996. Meantime he was also a lecturer at the Faculty (advanced course on satellite geodesy), where he received titles Associate Professor in 2000 and then in 2009 Professor of Theoretical and Space Geodesy. He was a consultant of several postdocs and a member of the Faculty’s committee for postdoctoral studies.His specialisation involves the study of orbital resonances of artificial satellites and studies of the Earth’s gravity field, satellite altimetry and gradiometry, static as well as variable gravity field. Now, he is interested mostly in geo-applications of the recent Earth’s gravitational field models. He has been cooperating for a long time with several institutes in Germany, USA, Egypt, and elsewhere. He has also been interested in archaeoastronomy; he accomplished series of field measurements in Mesoamerica, Peru and China between 1997 and 2011.Jan Kostelecký (*1946 in Prague) is a senior researcher in geodesy, space geodesy and geodynamics. He has published over 260 research articles and several books on a broad array in space geodesy. He studied geodesy and cartography at the Faculty of Civil Engineering, Czech Technical University in Prague, he obtained his master‘s degree in 1969. Then in 1971 he started to work as a researcher at the Research Institute of Geodesy and Cartography, Czech Republic, in this institute he has been working to this day. He obtained the PhD degree in 1983.Simultaneously since 1983 he worked at the Faculty of Civil Engineering, Czech Technical University in Prague, since 1992 as an Associate Professor and since 1997 as a Professor of Theoretical and Space Geodesy, since 2011 he has become the Professor Emeritus. He is also active as a teacher at the Faculty of Mining and Geology, Technical University of Ostrava. His research is especially concerned with the determination and application of the gravity field of the Earth, geodynamics and the establishment of geodetic networks.Aleš Bezděk (*1970 in Prague) is an academic worker in the field of astrodynamics and space geodesy. He studied physics and astronomy at the Charles University in Prague, where he obtained his master’s (1997) and PhD (2004) diplomas. Since 2001 he has been working at the Astronomical Institute, Czech Academy of Sciences. His research interests include orbital dynamics of low Earth artificial satellites, time‑variable gravity field, orbital resonances, nongravitational forces, atmospheric drag, space accelerometers, applied time series analysis. He co-authored twenty-six peer-reviewed journal articles, ten papers in conference proceedings, two monographs. He has been cooperating with researchers from France, Germany, Netherlands, USA and other countries.
