HR: 12:05h
AN: G41C-08    [PDF]
TI: Recovering Height and Geodetic Scale with GPS
AU: * Yunck, T
EM: tpy@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Heflin, M
EM: michael.b.heflin@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Webb, F
EM: frank.h.webb@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Dong, D
EM: danan.dong@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Kedar, S
EM: sharon.kedar@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Willis, P
EM: pascal.r.willis@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AB: As the techniques of space geodesy - satellite laser ranging (SLR), very-long-baseline interferometry (VLBI), and the Global Positioning System (GPS) - continue to improve, much effort is being focused on applying them to refine the global reference frame in support of geophysical research. One of the more challenging quantities to pin down is the frame's "absolute scale," which is directly related to the heights of the observing sites. While the absolute scale is itself of little interest, its long-term stability is critical. Spurious variations in the scale over time would manifest as apparent variations in the size of the earth, compromising studies of sea level change, post-glacial rebound, and the like. It is generally agreed that of the three operational space geodetic techniques, VLBI is pre-eminent in both the accuracy and stability of scale determination, followed closely by SLR. The performance of GPS in determining scale is not as well understood and is the subject of considerable debate. With its broad-beam transmitting and receiving antennas GPS is subject to multipath and direction-dependent phase variations, raising doubts concerning the quality of its height and scale solutions. Opinions range from "scale with GPS is undefined" to "GPS scale accuracy approaches that of VLBI and SLR." In this presentation we step through the arguments and evidence concerning GPS scale determination and present precise new results that may help to settle the question.
DE: 1243 Space geodetic surveys
DE: 1247 Terrestrial reference systems
SC: Geodesy [G]
MN: 2003 Fall Meeting