HR: 0800h
AN: G41C-0373    [Abstracts]
TI: Recent Advancements in the Determination of Earth Orientation Combination Solutions and Predictions
AU: * Johnson, T J
EM: johnson.thomas@usno.navy.mil
AF: U.S. Naval Observatory, Earth Orientation Department 3450 Massachusetts Ave NW, Washington, DC 20392-5420 United States
AU: Kosek, W
EM: kosek@cbk.waw.pl
AF: Space Research Center, Polish Academy of Sciences Ul. Bartycka 18a, Warsaw, 00-716 Poland
AU: Kalarus, M
EM: kalma@maia.usno.navy.mil
AF: U.S. Naval Observatory, Earth Orientation Department 3450 Massachusetts Ave NW, Washington, DC 20392-5420 United States
AU: Kalarus, M
EM: kalma@maia.usno.navy.mil
AF: Space Research Center, Polish Academy of Sciences Ul. Bartycka 18a, Warsaw, 00-716 Poland
AU: Lambert, S
EM: sbl@CygX3.usno.navy.mil
AF: U.S. Naval Observatory, Earth Orientation Department 3450 Massachusetts Ave NW, Washington, DC 20392-5420 United States
AU: Wooden, W
EM: wooden.william@usno.navy.mil
AF: U.S. Naval Observatory, Earth Orientation Department 3450 Massachusetts Ave NW, Washington, DC 20392-5420 United States
AB: The Earth's orientation is described using five parameters. The longitude and obliquity of the celestial ephemeris pole define the orientation of the Celestial Ephemeris Pole (CEP) with respect to the celestial reference frame. The orientation of the CEP with respect to the terrestrial reference frame is described by the polar motion (PM) parameters x and y, while the measure of the angle about the rotation axis through which the solid Earth has rotated is defined as universal time (UT1). In addition to several practical applications such as navigational correction, Earth Orientation Parameter (EOP) solutions are useful in studying the interaction of the solid Earth with its fluid envelope as well as climate change. Therefore, many users need accurate near-real time EOP solutions with predictions. The International Earth Rotation and Reference Systems Service (IERS) Rapid Service/Prediction Center (RS/PC), located at the U.S. Naval Observatory, combines over 2700 EOP observations produced from space geodetic technique observations, such as Satellite Laser Ranging (SLR), Global Positioning System (GPS), and Very Long Baseline Interferometry (VLBI), to produce a daily EOP solution with predictions. Since the beginning of the IERS combination pilot project, minimally constrained intra-technique combinations are regularly available from all geodetic technique services. Because of the need for more accurate predictions, the RS/PC is constantly looking for better approaches and observations to meet these new requirements. This study examines the RS/PC's recent efforts to improve the daily and weekly IERS Bulletin A EOP solutions and predictions produced using these intra-technique combinations from the International Laser Ranging Service (ILRS), International GNSS Service (IGS), International VLBI Service (IVS), and the International DORIS Service (IDS). Future modifications to the methodology used by the RS/PC for combination and prediction are discussed. These new EOP solutions are compared to the currently available IERS EOP series and the excitation functions computed from atmospheric and oceanic angular momentum estimates from global numerical models.
DE: 1200 GEODESY AND GRAVITY
DE: 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
DE: 1239 Earth rotation variations
DE: 1241 Satellite geodesy: technical issues (6994, 7969)
SC: Geodesy [G]
MN: Fall Meeting 2005