Development of Real-time SNUDGPS via Ionospheric and Tropospheric Corrections Sep 1, 1999· Changdon Kee , Doohee Yun. · 0 min read Last updated on Sep 1, 1999 Authors Changdon Kee Professor ← A Solution of Natural Way to Implement WADGPS in East-Asia: Decentralized WADGPS Sep 1, 1999 Flight Test of Helicopter Landing System Using Real-Time DGPS Sep 1, 1999 →