Variation in EOP and Station Coordinate Solutions from the Canadian Active Control System (CACS)

Since August 1992, precise GPS satellite ephemerides, Earth Orientation Parameters (EOP) and tracking station coordinates have been generated daily at the Master Active Control Station (MACS) of the Geodetic Surveys Division (GSD) as part of the International GPS Service for Geodynamics (IGS). A modified version of the GIPSY II software developed at the Jet Propulsion Laboratory is used to process data from 6 to 8 CACS sites and up to 20 globally distributed tracking stations. Analysis of daily solutions for the CACS station coordinates shows a centimeter level precision of the mean weekly values and good agreement with the International Earth Rotation Service (IERS) Terrestrial Reference Frame (ITRF). Systematic variations and trends at this level have implications for studies of regional crustal deformations approaching mm or ppb resolution.