UHF Radio Frequency Modules for Satellite-Ground Communication
Matheoud, Alessandro Valentino
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This thesis is devoted to the development of a bidirectional telecommunication system for space applications. The module is going to be integrated in the AraMiS architecture, that is an innovative philosophy of small satellites based on tile-modularity and the use of low-cost commercial components. The objective is to design the electronic board, the antenna apparatus and the control software to handle both the communication protocol and the housekeeping functions. According to the AraMiS speci cations, the main constraints are collected in Table I. After an introduction referring to space-environment related issues and the state of the art in university satellites, the hardware design is carried out. Technical choices related to frequency selection, modulation and suitable equipment are taken and justi ed according to the power budget, project constraints and the availability of speci c products on market. A set of devices is analyzed in terms of key-parameters in order to lter the most appropriate ones for each goal, then main block-schematics are provided. By means of speci c CAD tools, both schematics and PCB implementation are performed and depicted in the following chapters, then the C++ control software is designed to drive the communication system, the processing unit and all the housekeeping sensors. Since only COTS components are going to be used due to the low-cost goal and those are neither space dedicated nor radiation robust, both protection circuits and speci c software routines must be implemented in order to keep electronic boards in safe operating region. Such a precaution is fundamental to prevent the mission failure in case of SEUs. After that, the propagation environment is studied and the most common UHF radiating systems for satellite-ground communications are described. Finally, a suitable AraMiS antenna and speci c microwave circuits are designed to ensure both impedance matching and high radiation e ciency in the band of interest. In order to assure the system compatibility within the AraMiS framework and full technical integration with the other subsystems, a UML description for the entire project documentation is developed and steadily updated in the project library.
radio frequency telecommunication system
electronic systems within the space environment