Deflection of the Vertical Components from GPS and Precise Leveling Measurements in Hong Kong

Deflection of the vertical components of a station located in Hong Kong are estimated from the ellipsoidal height differences inferred from global positioning system (GPS) measurements and orthometric height differences calculated from precise leveling using a simple formulation. The agreement of the deflection of the vertical components $\xi$ and $\eta$ obtained from the experiment ( $-7.3\pm 1.6$ , $5.3\pm 4.3\text{arc seconds}$ , respectively) with the deflection of the vertical components calculated from the EGM96 model ( $-7.6$ , and $3.2\text{arc seconds}$ , respectively) show that the approach can be used at a local scale using existing leveling networks to produce a detailed map of deflection of vertical components to be used in surveying applications and also for checking the reproducibility of potential alternative solutions.