GAPS for Atmospheric Studies (GAPS-ATM): Preliminary Results

English Abstract:

Precise Point Positioning (PPP) is a well-established method of satellite positioning data processing. Since late 1990’s, several developments have been made in order to take into account the impact of atmospheric effects on the satellite signals such as the ones caused by troposphere and ionosphere. At first, these effects were modelled in order to improve the quality of the estimated coordinates. Lately, by modelling the effects, new researches moved towards correlating the positioning errors with different atmospheric activities. Nowadays, GNSS data is widely used to estimate several different “side” parameters such as water vapor in the atmosphere and electron density. In this work, we use GPS Analysis and Processing Software (GAPS), a PPP software developed and maintained at UNB, to constrain known and nuisance - in this scope - parameters as the receiver’s antenna final coordinates, and estimate atmosphere activity indexes. Among many parameters of interest, one can highlight troposphere wet and dry delay components and horizontal gradients, Total Electron Content (TEC) for each satellite in view, Electronic Gradients over time and others. An online platform is under development to allow the user to submit its own GNSS data and antenna coordinates to obtain a processing reporting focusing not on position estimation, but on atmospheric parameters represented in time series, plots and maps. Our first results show that the combination of PPP and the correct constraining of coordinates is a reliable alternative to estimate the atmospheric influence over satellite signals and, hence, estimate the behavior of the atmosphere in several different ways. By developing and implementing new tools on GAPS and focusing on the specific needs of atmospheric researchers, GAPS-ATM shows itself as an innovative and pioneer initiative among the GNSS post-processing packages available commercially or not.