Potential of Using Multi-Velocities in the Process of Updating Coordinates Obtained with PPP

Abstract

Currently, in the procedure of temporal updating of coordinates, constant and unique speeds are adopted in time (monovelocity). However, this research proposes to evaluate the potential of performing the aforementioned procedure with the application of multi-speed, that is, attributing more than one speed to the same point, each one being used in specific periods of the procedure. Ideally, these velocities are estimated through time series of coordinates with at least two years each, which together comprise the entire period of the desired temporal update. Using data from BOAV, NAUS, VICO, ROCK, LORS and CTA1 stations, the planimetric and altimetric discrepancy resulting from updating the coordinates for periods of 8 and 10 years was calculated. Considering the results obtained, it was observed that the multi-speeds provided better (or similar) planimetric results when compared to those obtained with the monovelocity for most of the stations used (5 out of 6 stations). The results obtained in the updates with the application of multivelocity estimated with half of the positional series (4 and 5 years) presented mostly millimeter order, either in an update of 8 or 10 years and in stations located near or far from the edges of the plates or under strong effects. of hydrological loads. However, in altimetry, the best (or similar) results of this procedure were verified in 3 of the 6 stations. When compared to widely used velocity models, the multivelocity update proved to be effective, presenting better results than the global models ITRF2000 and NUVEL-1A and regional models VEMOS2009 (used by IBGE-PPP) and VEMOS2017.