Trabalho de Conclusão de Curso de Graduação
Análise da correção do erro ionosférico em receptores GPS de frequência simples a partir da implementação do algoritmo de Klobuchar em Python
Fecha
2021-02-17Autor
Silva, Jeferson Rodrigues
Institución
Resumen
The Selective Availability (SA) technique was deactivated on May 2, 2000, since then the biggest
source of errors in positioning with the Global Positioning System (GPS) has come to be
related to the ionosphere. The ionospheric error is directly proportional to the total electron
content (TEC) present along the path taken by the signal in the ionosphere. TEC undergoes
variations in time and space and is influenced by several variables such as: solar cycle, time of
year, time of day, geographic location and geomagnetic activity. In simple frequency systems,
the correction of these errors is associated with the use of an ionospheric model that estimates
the amount of TEC present in the ionospheric layer and the evaluation of these models is done
by analyzing the post-processed results of the applied corrections. In this work were evaluated:
IONEX files of corrections from the Global Ionosphere Maps (GIM) service generated by the
International GNSS Service (IGS) and the response to the Klobuchar algorithm designed by
the GNSS application package RTKLib. To validate RTKLib’s response to IONEX files, maps
were generated from the implementation of the Klobuchar algorithm in Python and as a basis
of comparison, double frequency correction was used, since it corrects about 99% of errors
associated with the ionosphere . The post-processing method applied by RTKLib proved to be
effective, returning the expected values, so the IGS maps were more accurate than the correction
applied by the Klobuchar method, justifying its use by the scientific community as a basis
for comparison in error correction in single frequency GPS receivers.