Artur Fischer is a Postdoctoral Fellow in the Department of Land Surveying and Geospatial Science (LSGS) at The Hong Kong Polytechnic University (PolyU). He received his Ph.D. in Civil Engineering, Geodesy, and Transportation from the University of Warmia and Mazury in Olsztyn, Poland, in 2025. His research interests include DIA theory, mixed-integer GNSS model estimation and testing, GNSS integer ambiguity resolution, and high-precision applications of satellite positioning, navigation, and timing (PNT) systems.