The Global Positioning System (GPS) uses accurate, stable atomic clocks in satellites and on the ground to provide world-wide position and time determination. These clocks have gravitational and motional frequency shifts which are so large that, without carefully accounting for numerous relativistic effects, the system would not work. This paper discusses the conceptual basis, founded on specia...

FFT and complex algebra-based methods of spherical harmonic analysis and synthesis are presented. Two computer programs in FORTRAN are developed based on the methods. Both general and special cases are discussed. Special cases involve the analyses of gravity changes of the hydrological origin and the atmospheric origin. Functionals of the Earth’s gravity field such as gravity anomaly and geoida...

[1] Eight years of TOPEX/Poseidon altimeter-derived sea height anomaly and climatological hydrographic data are used to investigate the temporal and spatial variability of the North Brazil Current (NBC) retroflection and the North Equatorial Countercurrent (NECC). The NBC retroflection exhibits a mean position of 6.6 N± 2.0 , with a strong annual signal and year-to-year variability. The annual ...

In dynamic orbit determination, the problem is that a batch estimator assumes use of more sophisticated models for both force and observation models, dealing with large amounts of observations. As a result, the computational workload may not be acceptable for onboard orbit determination. In this paper, the short-arc batch estimation is experimentally studied in order to address both estimation ...

The Global Positioning System (GPS) uses accurate, stable atomic clocks in satellites and on earth to provide world-wide position and time determination. These clocks have relativistic frequency shifts which are so large that, without accounting for numerous relativistic e ects, the system would not work. This paper discusses the conceptual basis, founded on special and general relativity, for ...

Ionospheric tomography using GPS data has been reported in the literature and even the application to radar altimeter calibration was succesfully carried out in a recent work ( [1]). We here present a new software tool, called Global Ionospheric Stochastic Tomography software (GIST), and its powerful capability for ingesting GPS data from different sources (ground stations, receivers on board L...

Effects of spatial regularity and locality assumptions in the extended Kalman filter are examined for oceanic data assimilation problems. Biorthogonal wavelet bases are used to implement spatial regularity through multiscale approximations, while a Markov random field (MRF) is used to impose locality through spatial regression. Both methods are shown to approximate the optimal Kalman filter est...

Five acoustic Doppler current prooler (ADCP) moorings were deployed across the central West Florida Shelf (WFS) during 1995 and early 1996, spanning the 300 m to 30 m isobaths. Current speeds are found to generally decrease toward shallower depths. Neighboring ADCPs frequently record currents owing in opposite directions. Altimetry from TOPEX-Poseidon is used to indicate the position of the Loo...