DGPS Orthometric Heights accuracy Analysis GPS model Deformation Ellipsoidal Height GNSS Observations Geoid Monitoring Orthometric height geoid geometric least squares least squares adjustment Accuracy AllTrans Arithmetic Belt and Zone Parameters Bicubic Centroid Columbus Comparative Analysis Conventional Geodetic Techniques Coordinates Datum Differential GPS Ellipsoidal Ellipsoidal Heights Epoch GNSS GeoCalc Geodetic Geoid Model Geoid Undulation Geoid model Geoid undulation Geometric Geometric Surface Geometric geoid Geometric geoid surface Grashof's law Gravimetric Gravimetric geoid height Gravimetric-geometric Harmonic Height Large Structure Least Squares Technique Positioning