Wide Area Differential GPS as a Future Navigation System in the U. S. Apr 1, 1994· Changdon Kee , Parkinson , B. W. · 0 min read Last updated on Apr 1, 1994 Authors Changdon Kee Professor ← Flight Trials of the Wide-Area Augmentation System (WAAS) Sep 1, 1994 Static Test Results of Wide Area Differential GPS Sep 1, 1993 →