HR: 1330h
AN: G22B-0308    [PDF]
TI: Millimeter QC of the ITRF using SLR
AU: * Husson, V S
EM: van.husson@honeywell-tsi.com
AF: HTSI, 7515 Mission Drive, Lanham, MD 20706 United States
AU: Ries, J C
EM: RIES@CSR.UTEXAS.EDU
AF: CSR, 3925 W. Braker Lane, Suite 200, Austin, TX 78759-5321 United States
AU: Eanes, R J
EM: EANES@CSR.UTEXAS.EDU
AF: CSR, 3925 W. Braker Lane, Suite 200, Austin, TX 78759-5321 United States
AU: Horvath, J E
EM: julie.horvath@honeywell-tsi.com
AF: HTSI, 7515 Mission Drive, Lanham, MD 20706 United States
AB: Using Satellite Laser Ranging (SLR) data, the 3-dimensional quality of the International Laser Ranging Service (ILRS) network coordinates can be objectively evaluated to the few millimeters (mm) level. SLR was used to define the ITRF200 origin and scale and its rate. Certain SLR sites in ITRF2000, which had performance problems or short occupational histories, do have questionable coordinates and velocities (e.g. Riyadh, Beijing). The standard error associated with a coordinate set is one-way to quickly access its quality, but in reality the `TRUE' coordinate error could be an order of magnitude larger than the standard error. Another way of performing a site coordinate reality check it by treating any site with a height rate larger than a few mm per year as potentially suspect. For example, Beijing and Riyadh height rates of +23 and -17 mm per year; respectively, immediately raises concern. For a given site, the geometry of the ground tracks from LAGEOS and Jason ranging coupled with pass-by-pass range and time bias estimates from global short arcs (i.e. 1-3 days) can be examined to determine the accuracy of the horizontal components of the coordinates. To determine the accuracy of the vertical component involves simultaneously estimating station positions and range biases every 28-days for a period of at least a few months. Currently, Riyadh ITRF2000 coordinates at epoch 2003 are in error by 10 centimeters (cm) in both North and Up and 5 cm in East. Two SLR analysts groups (ASI and CSR) have computed new Riyadh positions using LAGEOS and a combination of LAGEOS and Jason data, respectively. Their coordinates agree to a 3 cm, 1cm, and 2cm in North, East, and Up, respectively. We will use the global SLR LAGEOS and Jason normal point data sets in 2002 and 2003 to resolve which Riyadh coordinate set is more accurate.
DE: 1247 Terrestrial reference systems
SC: Geodesy [G]
MN: 2003 Fall Meeting