@InProceedings{EspejoCosMorPauMon:2019:EqLoIo,
author = "Espejo, Teddy M. Surco and Costa, Emanuel and Moraes, Alison de
Oliveira and Paula, Eurico Rodrigues de and Monico, Jo{\~a}o
Francisco Galera",
affiliation = "{Pontif{\'{\i}}cia Universidade Cat{\'o}lica do Rio de Janeiro
(PUC-Rio)} and {Pontif{\'{\i}}cia Universidade Cat{\'o}lica do
Rio de Janeiro (PUC-Rio)} and {Instituto de Aeron{\'a}utica e
Espa{\c{c}}o (IAE)} and {Instituto Nacional de Pesquisas
Espaciais (INPE)} and {Universidade Estadual Paulista (UNESP)}",
title = "Equatorial and Low-Latitude Ionospheric Effects on GPS Signals in
Space and on Ground Based Augmentation System Operations",
year = "2019",
organization = "AGU Fall Meeting",
abstract = "Ground Based Augmentation Systems (GBAS) have been developed to
meet the safety requirements of air navigation,using differential
corrections to provide higher accuracy during aircraft approach
and landing operations. However, ionospheric delays and
scintillation cause positioning errors that degrade the accuracy,
performance and availability of Air Navigation Systems that
operate using the Global Positioning System (GPS), particularly in
the equatorial and low-latitude regions. The propagation and
degradation of GPS signals in space due to ionospheric effects are
the focus of this work, which describes a simulation model of the
GPS observables. For each active communication channel between a
satellite and a reference ground receiver or aircraft,the
pseudorange PR, carrier phase \Φ and received power C for
the GPS L1 signals were simulated, considering the clock errors,
ionospheric and tropospheric delays, multipath, amplitude and
phase scintillation, random errors, free-space loss and antenna
gains. Ionospheric delays were estimated through statistical
distributions of residuals between the vertical Total Electron
Content (vTEC) at associated 400-km ionospheric pierce points
(IPP)estimated from the data recorded by the dual-frequency GPS
receivers of the RBMC/IBGE network,and the relative vTEC estimated
by the latest version of the International Reference Ionosphere
(IRI). Samples of amplitude and phase scintillation were generated
according to \α \μ probability distributions,
conforming to data collected by receivers of the CIGALA/CALIBRA
network, located in different geomagnetic latitudes. Next, the
results from the above model were processed by algorithms to
detect possible degradations in the GPS signals, isolate failures,
smooth and correct acceptable ones, and transmit correction
messages to aircrafts through the VDB (VHF Data Broadcast).GBAS
availability was also evaluated by computing the Vertical
Protection Levels (VPL). This contribution will present and
discuss statistical analyses of position errors resulting from the
simulation of GPS observables and GBAS operations for different
combinations of geophysical parameters(solar and geomagnetic
activity, geomagnetic latitude, local time and season) and
scenarios.",
conference-location = "San Francisco, CA",
conference-year = "09-13 dec.",
language = "en",
targetfile = "espejo_equatorial.pdf",
urlaccessdate = "29 mar. 2024"
}