Use of Global Positioning System Measurements to Determine Geocentric Coordinates and Variations in Earth Orientation

R P Malla; S -C Wu; S M Lichten

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NASA NTRS · 19940009899

Use of Global Positioning System Measurements to Determine Geocentric Coordinates and Variations in Earth Orientation

R P Malla·S -C Wu·S M Lichten

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Abstract

Geocentric tracking station coordinates and short-period Earth-orientation variations can be measured with Global Positioning System (GPS) measurements. Unless calibrated, geocentric coordinate errors and changes in Earth orientation can lead to significant deep-space tracking errors. Ground-based GPS estimates of daily and subdaily changes in Earth orientation presently show centimeter-level precision. Comparison between GPS-estimated Earth-rotation variations, which are the differences between Universal Time 1 and Universal Coordinated Time (UT1-UTC), and those calculated from ocean tide models suggests that observed subdaily variations in Earth rotation are dominated by oceanic tidal effects. Preliminary GPS estimates for the geocenter location (from a 3-week experiment) agree with independent satellite laser-ranging estimates to better than 10 cm. Covariance analysis predicts that temporal resolution of GPS estimates for Earth orientation and geocenter improves significantly when data collected from low Earth-orbiting satellites as well as from ground sites are combined. The low Earth GPS tracking data enhance the accuracy and resolution for measuring high-frequency global geodynamical signals over time scales of less than 1 day.

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R P Malla, S -C Wu, S M Lichten. 1993-08-15. Use of Global Positioning System Measurements to Determine Geocentric Coordinates and Variations in Earth Orientation. https://ntrs.nasa.gov/citations/19940009899

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