HR: 1340h
AN: G43A-0914    [Abstracts]
TI: Analysis of the second and third order ionospheric effects for GNSS positioning in Brazil
AU: * Marques, H A
EM: haroldoh2o@gmail.com
AF: Haroldo Antonio Marques, Roberto Simonsen - 305 Centro Educacional, Presidente Prudente, SP 19060-900, Brazil
AU: Monico, J F
EM: galera@fct.unesp.br
AU: Rosa, G P
EM: gpoleszuk@gmail.com
AF: Guilherme Poleszuk dos Santos Rosa, Roberto Simonsen - 305 Centro Educacional, Presidente Prudente, SP 19060-900, Brazil
AB: The Global Positioning System (GPS) transmits two frequencies, wich allow to correct the first order ionospheric effects through the ionospheric-free observable. These effects, characterized by the phase advance and group delay, cause several errors in the GPS positioning. The second and third order ionospheric effects, generally neglected in the GPS data processing, also introduce sazonal variations of few millimeters in the station position, besides centimeter diurnal variations in the latitude and height. The first order effect is directly proportional to the Total Electron Content (TEC) in the atmosphere. The second and third order are also dependent of TEC, besides the Earth geomagnetic field and the maximum electron density, respectively. In this paper, the second and third order ionospheric effects were taken into account in the GPS data processing. This processing was accomplished using GPS data of the Brazilian region, involving relative and precise point positioning (PPP), either in static or kinematic mode. The analysis was accomplished considering the discrepancies between the solution with and without the cited corrections. For the PPP kinematic scenario, considering low ionospheric activities, the results showed effects of the order of 2 and 4 mm for the horizontal and height components, respectively. For more active ionosphere the discrepancies reached up to 1 cm. For relative processing using baselines larger than 100 km, the discrepancies reached the order of 2 and 7 mm in the height stations for low and more activity ionosphere, respectively. These results and new ones will take part of this presentation.
DE: 1241 Satellite geodesy: technical issues (6994, 7969)
DE: 1243 Space geodetic surveys
DE: 1299 General or miscellaneous (1709)
DE: 2415 Equatorial ionosphere
DE: 2441 Ionospheric storms (7949)
SC: Geodesy [G]
MN: 2007 Fall Meeting