Quality Control Algorithms on Wide-area Reference Station for WAAS Jun 1, 1996· Changdon Kee , Walter , T. , Enge , P. , Parkinson , B. W. · 0 min read Last updated on Jun 1, 1996 Authors Changdon Kee Professor ← GPS Satellite Ephemeris Error Estimation using National Satellite Testbed (NSTB) Data Jun 1, 1996 Wide Area Differential GPS (WADGPS) as a Future Navigation System in the United States Apr 1, 1996 →