An Algorithm for Inter-frequency Bias Calibration and Application to WAAS Ionosphere Modeling Sep 1, 1995· Yi-Chung Chao , Yeou-Jyh Tsai , Todd Walter Changdon Kee , Per Enge , Brad Parkinson · 0 min read Last updated on Sep 1, 1995 Authors Changdon Kee Professor ← Wide Area Differential GPS (WADGPS) as a Future Navigation System in the United States Apr 1, 1996 Validation of the RTCA Message Format for WAAS Sep 1, 1995 →