Analysis of Total Electron Content (TEC) Near Real Time Using Dual Frequency GPS Data (Study Case: Surabaya)Mokhamad Nur Cahyadi, Almas Nandityo Rahadyan and Buldan MuslimE3S Web Conf., 94 (2019) 05005DOI: https://doi.org/10.1051/e3sconf/20199405005