Geodetic Sciences
Geodetic Sciences Research Group
Doug Alsdorf, Michael Bevis, Christopher Jekeli, Alan J. Saalfeld, Burkhard Schaffrin, C. K. Shum
Geodetic science is concerned with the size and shape of the Earth, the realization of terrestrial reference frames, and the estimation of spatial coordinates, Earth orientation parameters, crustal motion and deformation, tides, the mean and time-variable gravity field, and mass fluxes associated with the Earth system. Geodetic measurements are made using ground, airborne and space-based instruments and sensors. They provide fundamental observations for many branches of the Earth sciences including geophysics, geodynamics, geomorphology, geology, oceanography, hydrology, glaciology, meteorology, space physics and climate change research. Increasingly, multiple geodetic measurement systems are being used to help resolve Earth system processes that produce signals that overlap in space and/or in time. For example satellite altimetry, tide gauges, SAR interferometry and GPS measurements are all being used to study changes in relative sea level that are caused by changes in the absolute vertical position of both the land and ocean surfaces. These changes are driven by mass transfer between the cryosphere and hydrosphere, postglacial rebound, changes in the density of seawater, and changes in the Earth's gravity field in space and in time. GPS measurements are also being used to study plate motion, the earthquake deformation cycle, mountain building, elastic responses to seasonal changes in environmental loading of the solid earth, atmospheric water vapor and pressure, and the ionsophere.
Geodetic science engages a wide range of mathematical problems and tools including linear algebra, fundamental boundary values problems, computational geometry, statistics, satellite orbital theory, adjustment theory, wavelets, spherical splines, signal processing, topology, map transformations and the encoding of geoinformation. The interface between geodesy and geophysics involves several branches of continuum mechanics (especially elasticity and viscoelasticity), the kinematic theory of plate tectonics, and inverse theory. Considerable emphasis is placed on devising and utilizing efficient numerical methods.
Geodetic science uses a wide range of instrumentation, such as ground- and space-based GPS, multi-spectral remote sensing (radar, InSAR, Lidar, laser and microwave altimetry, optical imaging), inertial sensors, and gravimeters and gravity gradiometers on airborne and satellite-borne platforms. Geodetic Science exposes its students to physics, mathematics, statistics, geophysics, and computer science, and encourages the optimal utilization of measurements. It attracts graduate students from around the world who majored in physics, mathematics, Earth science, computer science, engineering, and surveying or geomatics. OSU is recognized as having one of the world's leading Geodetic Science programs since the 1950s. Its research programs are funded by NSF, NASA, DoD, NOAA, and others. The research laboratories associated with the Division of Geodetic Science have state of the art GPS, inertial navigation, and computational equipment and software.