Unifying the Regional Height System Using Optic-Fiber Clock Network: A Simulation Test for Southeast Asia

Orthometric height datum systems are critical in the geodetic community. Nonetheless, individual nations or local regions maintain their distinct height systems. These systems, primarily determined by conventional spirit leveling, exhibit inhomogeneity, as the mean sea level does not represent an equi-geopotential surface. As such, accurately unifying global height systems is a persistent challenge. The gravity frequency shift equation provides a promising approach to this issue, offering a means to unify global height systems by comparing the frequencies of two distant clocks via optical fibers. In this study, we develop a model based on the Optical Fiber Frequency Transfer (OFFT) method, recognized for its unparalleled precision. We simulated a network of optical clocks interconnected by optical fibers to unify the height system across Southeast Asia. Our study suggests that the optical fiber clock network can realize height propagation between any two height datums at the centimeter level, providing a favorable opportunity for achieving regional height system unification.