Velocity Field Estimation Using GPS Precise Point Positioning: The South American Plate Case

GPS is essential in applications that require high (sub centimeter) positioning precision, such as in the velocity field estimation of tectonic plates. Normally, GPS relative positioning is used for this kind of application. However, GPS Precise Point Positioning (PPP) is a very simple and efficient method, which, as shown in this paper, can also be applied. This paper outlines the use of PPP for processing GPS data. Station coordinates and velocity vectors are inferred, and an estimation of the South American Plate rotation parameters (ΩX, ΩY and ΩZ) is given. The PPP repeatability of station coordinates is better than 9mm, and comparisons of the final solution with other sources, such as ITRF, NNR-NUVEL 1A and APKIM 2000 generally show good agreement. The formal precision of the station velocity is in the order of 0.6 mm/year, for horizontal and vertical components, which appears to be an optimistic value, and the quality of the estimated rotation parameters is better than those from other sources.