Grzegorz Grunwald, Adam Ciećko, Kamil Krasuski and Rafał Kaźmierczak 2021. The GPS / EGNOS Positioning Quality in APV-1 and LPV-200 flight procedures. Communications - Scientific letters of the University of Zilina. 23, 2 (Apr. 2021), E23-E34. DOI:https://doi.org/10.26552/com.C.2021.2.E23-E34.