Banca de DEFESA: ARTHUR AMARAL FERREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ARTHUR AMARAL FERREIRA
DATE: 07/07/2023
TIME: 10:00
LOCAL: Videoconferência
TITLE:

ANALYSIS AND PREDICTION OF SPACE WEATHER EVENTS AND THEIR IMPACTS ON SATELLITE NAVIGATION AND COMMUNICATION SYSTEMS

KEY WORDS:

Satellite Communication, Scintillation, Ionospheric Disturbances, Space Weather

PAGES: 146
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Eletrônica Industrial, Sistemas e Controles Eletrônicos
SPECIALTY: Automação Eletrônica de Processos Elétricos e Industriais
SUMMARY:

Space weather events can affect the operation of modern technological systems that humankind currently relies on, including electric power grids, spaceborne vehicles, radio wave communication, and navigation systems. Therefore, any new information that helps us to predict and better understand the space weather phenomena and their impact on our infrastructure and services is of the highest interest. In this framework, this manuscript presents the results of the investigation of different space weather phenomena, addressing primarily the large scale travelling ionospheric disturbances (LSTIDs), the substorms (assessed here via the Auroral Electrojet index, AE), and the effects of Faraday rotation and scintillation on UHF satellite communication. In the first part of this manuscript, a statistical analysis of the LSTIDs observed over mid-latitude Europe during the descending phase of solar cycle 24 is performed. In addition, an investigation on potential GNSS based indices that can serve as precursors for the occurrence of LSTIDs is presented. The results indicate that the Along Arc TEC Rate (AATR) index and ionospheric gradients are promising candidates that may support real-time monitoring of such disturbances. This manuscript also presents methodologies for predicting the substorms and the LSTIDs using solar wind data from Lagrangian Point L1. For predicting the AE index, a feed-forward artificial neural network model is proposed, and the results suggest that the solar irradiance may not influence the estimates. In addition, the results have shown that the combined information of interplanetary magnetic field (IMF) and solar wind velocity provide better estimates of the AE index. The IMF information is, however, dominant when compared to the solar wind velocity. Regarding the LSTIDs, different methodologies for their prediction over the European region using solar wind are investigated, and a new model is proposed, which to the best of the author’s knowledge, is the first model for LSTIDs activity prediction. The last part of this manuscript is devoted to investigating the effects of the Faraday Rotation and the ionospheric scintillation in the planning of the AlfaCrux mission, which is an amateur radio and educational mission coordinated by the Laboratory of Simulation and Control of Aerospace Systems of the University of Brasília, Brazil. Since Brazil is located in a region with high occurrence of ionospheric plasma bubbles and irregularities, assessing the risk of communication outage due to ionospheric scintillation is essential for planning and efficient use of the communication channel. In this framework, a new methodology for assessing the risk of communication outage based on the risk analysis from decision theory is proposed. This proposed methodology may be useful not only for the AlfaCrux mission, but for any other satellite communication mission operating in the UHF frequency band. The main contributions of the investigation presented in this manuscript are, therefore, the improvement in understanding of these SWe phenomena and their impacts and the development of strategies to predict them.

BANKING MEMBERS:
Externo à Instituição - JOÃO FRANCISCO GALERA MONICO - UNESP
Externo à Instituição - NORBERT JAKOWSKI
Externo ao Programa - 2180393 - ADOLFO BAUCHSPIESS
Interno - 2131191 - DANIEL GUERREIRO E SILVA
Interno - 1848167 - RENATO ALVES BORGES