Effect of Error in Unit Vector on DGPS Positioning Accuracy Jan 1, 1997· Changdon Kee , Parkinson , B. W. · 0 min read Last updated on Jan 1, 1997 Authors Changdon Kee Professor ← Comparison of Master Station User Algorithms for Wide-Area Augmentation System Jan 1, 1997 Wide Area Differential GPS Nov 1, 1996 →