Generation of Ionospheric Error and Confidence Estimates for WAAS Jun 1, 1996· Chao , Y. C. , Tsai , Y. J. , Evans , J. , Barrows , A. , Lawrence , Walter , T. Changdon Kee , Enge , P. , Powell , D. , Parkinson , B. W. · 0 min read Last updated on Jun 1, 1996 Authors Changdon Kee Professor ← Future Satellite Navigation System: Wide-area Augmentation System (WAAS) Jun 1, 1996 GPS Satellite Ephemeris Error Estimation using National Satellite Testbed (NSTB) Data Jun 1, 1996 →