Nik Zulkifli, Siti Sarah, Mardina Abdullah, and Mahamod Ismail. “Simulation of Ionospheric Error on GPS Signals Due to Changes in the Direction of Mobile Station Positions in Differential GPS”. Annals of Geophysics 54, no. 6 (January 30, 2012). Accessed April 16, 2024. https://www.annalsofgeophysics.eu/index.php/annals/article/view/4973.