@MastersThesis{Madeira:2022:CaGNUs,
author = "Madeira, Roberto Livy da Costa",
title = "Calibration of GNSS-TEC using ionosonde data and low latitude TEC
map generation",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2022",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2022-05-27",
keywords = "receiver bias, Global Navigation Satellite System (GNSS),
ionosonde, ionosphere, Total Electron Content (TEC), erros de
receptor, ionossonda, ionosfera, Conte{\'u}do Eletr{\^o}nico
Total (TEC).",
abstract = "Biases in Global Navigation Satellite System (GNSS) receivers can
degrade satellite signals used for ionospheric studies. In this
work, we propose the receiver bias removal using ionosonde data
collected at 6.5 LT, when the ionosphere is supposed to have
minimal Total Electron Content (TEC) gradient along magnetic
longitudes of the South American sector. Also, the adapted
\α-Chapman function was used in order to include the
plasmaspheric contribution in the ionosonde-derived TEC (IONTEC)
calculations. For each day, a function able to describe the
vertical TEC (V TEC) on magnetic latitudes IONTEC(MLat) was fitted
on the ionosonde data and used to calibrate the TEC obtained from
the GNSS stations of the networks Rede Brasileira de Monitoramento
Cont{\'{\i}}nuo (RBMC), Instituto Nacional de Ci{\^e}ncia e
Tecnologia Tecnologia GNSS no Suporte {\`a} Navega{\c{c}}{\~a}o
A{\'e}rea (INCT GNSSNavAer), and Syst{\`e}me dObservation du
Niveau des Eaux Littorales (SONEL). The estimated biases where
compared to the results from the University of Texas at Dallas
(UTD) code for TEC calibration and both have shown good agreement.
Also, the coherence of the method for three consecutive days,
March 21-23, 2021, a period with low solar activity, was analyzed
and it has shown to be satisfactorily stable by producing the
average standard deviation of the receiver bias from the RBMC
network equal to 0.6376 TECU; a distinct case occurred at
Cachoeira Paulista Station, which experienced large variation in
its bias through the three days, even so, our method was able to
detect an estimate of the receiver bias, ensuring the continuity
of TEC data. Finally, was generated the TEC maps over the
Brazilian sector and neighboring regions using minimal curvature
method for interpolation and the maps were compared to the ones
produced by the Laboratorio de Meteorolog{\'{\i}}a Espacial,
Atm{\'o}sfera Terrestre, Geodesia, Geodin{\'a}mica, diseņo de
Instrumental y Astrometr{\'{\i}}a (MAGGIA laboratory). It was
noticed that just the maps generated with our method were able to
detect properly Equatorial Plasma Bubble (EPB) signatures, such
that these signatures were also identified by All-Sky imager
pictures and S4 data. RESUMO: Erros em receptores de Global
Navigation satellite System (GNSS) podem corromper sinais de
sat{\'e}lites usados para estudos da ionosfera. Neste trabalho,
n{\'o}s propomos a remo{\c{c}}{\~a}o de tend{\^e}ncias de
receptores usando dados de ionossonda coletados {\`a}s 6.5, hora
local, quando se sup{\~o}e que a ionosfera tem gradiente
m{\'{\i}}nimo no Conte{\'u}do Eletr{\^o}nico Total (TEC) em
longitudes magn{\'e}ticas no setor Sul-americano. Usou-se a
fun{\c{c}}{\~a}o Chapman-\α adaptada de tal maneira a
incluir as contribui{\c{c}}{\~o}es da plasmasfera no
c{\'a}lculo do TEC derivado de ionossonda (IONTEC). Para cada
dia, uma fun{\c{c}}{\~a}o capaz de aproximar o TEC vertical (V
TEC) em latitudes magn{\'e}ticas (IONTEC(MLat)) foi ajustada nos
dados de ionossondas e usada para calibrar os valores de TEC
obtidos com as informa{\c{c}}{\~o}es dos receptores GNSS da Rede
Brasileira de Monitoramento Cont{\'{\i}}nuo (RBMC); e, redes do
Instituto Nacional de Ci{\^e}ncia e Tecnologia Tecnologia GNSS no
Suporte {\`a} Navega{\c{c}}{\~a}o A{\'e}rea (INCT GNSS-NavAer)
e Syst{\`e}me dObservation du Niveau des Eaux Littorales (SONEL).
As tend{\^e}ncias estimadas foram comparadas {\`a}s obtidas pelo
c{\'o}digo University of Texas at Dallas (UTD) de
calibra{\c{c}}{\~a}o de TEC, onde ambos mostraram boa
concord{\^a}ncia. Tamb{\'e}m foi investigada a coer{\^e}ncia do
m{\'e}todo para tr{\^e}s dias consecutivos de baixa atividade
solar, 21-23/03/2021, o qual se mostrou satisfatoriamente
est{\'a}vel com um desvio padr{\~a}o m{\'e}dio para as
tend{\^e}ncias dos receptores RBMC igual a 0.6376 TECU; um caso
peculiar ocorreu na esta{\c{c}}{\~a}o de Cachoeira Paulista,
{\`a} qual experimentou grande varia{\c{c}}{\~a}o nas suas
tend{\^e}ncias nos tr{\^e}s dias analisados, mesmo assim, nosso
m{\'e}todo foi capaz de detectar e estimar o valor correto,
garantindo a continuidade dos dados de TEC. Finalmente, foram
gerados mapas de TEC sobre o setor brasileiro e rego{\~o}es
vizinhas atrav{\'e}s de interpola{\c{c}}{\~a}o com m{\'e}todo
da curvatura m{\'{\i}}nima e comparados com os mapas do
Laboratorio de Meteorolog{\'{\i}}a Espacial, Atm{\'o}sfera
Terrestre, Geodesia, Geodin{\'a}mica, diseņo de Instrumental y
Astrometr{\'{\i}}a (MAGGIA), onde apenas os mapas gerados pelo
nosso m{\'e}todo foram capazes de detectar propriamente
assinaturas de Bolhas de Plasma Equatoriais (EPBs), onde tais
assinaturas tamb{\'e}m foram identificadas por imageadores
All-Sky e dados de {\'{\i}}ndice S4.",
committee = "Dal Lago, Alisson (presidente) and Souza, Jonas Rodrigues de
(orientador) and Aguiar, Claudinei Rodrigues de (orientador) and
Paula, Eurico Rodrigues de and Monico, Jo{\~a}o Francisco
Galera",
englishtitle = "Calibra{\c{c}}{\~a}o do GNSS-TEC usando dados de ionossonda e
gera{\c{c}}{\~a}o de mapas de TEC em baixas latitudes",
language = "en",
pages = "58",
ibi = "8JMKD3MGP3W34T/472R79S",
url = "http://urlib.net/ibi/8JMKD3MGP3W34T/472R79S",
targetfile = "publicacao.pdf",
urlaccessdate = "05 jun. 2024"
}