Real-time Flight Demonstration of Wide-Area Differential GPS (WADGPS) Feb 1, 1995· Powell , D. , Walter , T. Changdon Kee , Chao , Y. C. , Tsai , Y. J. , Evans , J. , Enge , P. , Parkinson , B. W. · 0 min read Last updated on Feb 1, 1995 Authors Changdon Kee Professor ← Real-time Flight Test Result of Wide-Area Differential GPS (WADGPS) Apr 1, 1995 Evaluation of Orbit and Clock Models for Real Time WAAS Jan 1, 1995 →