Arvutitehnika magistritööd enne 2014 – Master's theses before 2014

Permanent URI for this collectionhttps://hdl.handle.net/10062/25575

Browse

Browsing Arvutitehnika magistritööd enne 2014 – Master's theses before 2014 by Subject "estcube"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Designing, Implementing and Testing the Solar Power Harvesting System for ESTCube-1
    (Tartu Ülikool, 2011) Rantsus, Ramon
    Estonian Student Satellite project started in the summer of 2008 at Tartu University with the objective for promoting space and giving students a hands-on experience on developing space technologies. The main outcome of the project was pronounced to be a fully operational picosatellite ESTCube-1 - the first Estonian satellite. The goal of ESTCube-1 satellite is to deploy a single 10 meter long Hoytether in low Earth orbit using a centrifugal force. The success criteria for this objective is the deployment of the tether and the snapshot of the visual confirmation of the deployment. The successful tether deployment is needed to demonstrate technologies for a full-scale Electric Solar Wind Sail (ESAIL) test mission in the future. The concept of ESAIL has potential to become one of the most efficient space propulsion technologies in the history. ESAIL is based on the interaction between the positively charged particles in the solar wind with the positively charged tether net deployed from a satellite. Each tether is a fourfold Hoytether structure to be as light as possible, but to maintain the durability needed in the harsh space environment. The concept was proposed by Pekka Janhunen from Finnish Meteorological Institute (FMI) in 2006. The concept of ESAIL has potential to become one of the most efficient space propulsion technologies ever invented. ESTCube-1 Electrical Power System (EPS) is responsible for gathering power from solar panels, storing into batteries and distributing it to the whole system.The main goals of the current work were to: analyze solar panels characteristics and solar power harvesting concept; analyze the concept of Maximum Power Point Tracking (MPPT); analyze requirements for solar panel controller; propose a solar panel controller design for ESTCube-1; develop a solar panel controller prototype; test the algorithm of MPPT; test the efficiency of solar power harvesting. The work consists of eight Chapters. The Chapter 3 gives a more detailed overview of ESTCube-1 satellite with focus on EPS subsystem. Chapter 4 analyzes the concept of solar power harvesting and the need of MPPT. Also the general characteristics of solar cells are analyzed and the simple model of solar cell work is pointed out. Chapter 5 proposes the design layout of solar panel controller, the implementation of MPPT algorithm and the implementation of solar panel controller software. Based on the design layout, the solar panel controller prototype development with measurement analyzes are described in Chapter 6. Chapter 5 and 6 form the main body of the work. In Chapter 7 the future activities are proposed and in Chapter 8 most important results are concluded and the completion of goals is assessed.
  • Thumbnail Image
    Item
    ESTCube-1 satellite beacon
    (Tartu Ülikool, 2010) Kvell, Urmas
    ESTCube-1 shall be the first Estonian satellite to be launched in 2012. The mission has innovative scientific and educational objectives. The goal of ESTCube-1 satellite is to successfully deploy a single 10 meter long Hoytether structure in low Earth orbit using centrifugal force. The successful tether deployment is needed to demonstrate critical technologies for a full-scale Electric Solar Wind Sail (ESAIL) test mission in the future. The concept of ESAIL has potential to become one of the most efficient space propulsion technologies. It is based on the interaction between the positively charged particles in the solar wind with the positively charged tether net deployed from a satellite. Each tether is a four-fold Hoytether structure so it can be made very light but the whole structure shall retain the durability that is needed in a space environment. The concept was proposed by Pekka Janhunen from Finnish Meteorological Institute in 2006. ESTCube-1 is being developed by students from the University of Tartu and Tallinn University of Technology in tight cooperation with international partners from Finland (Finnish Meteorological Institute, University of Helsinki, Jyväskylä University) and Germany (DLR Bremen). ESTCube-1 communications subsystem (COM) is responsible for the communication between a ground station (GS) and the spacecraft. It can receive telecommands from the GS for setting different operating modes and requests to transmit data. There are two different types of downlink transmission modes: LPTM - Low Power Transmission Mode (Beacon) HPTM - High Power Transmission Mode (Data) The beacon is used for tracking the satellite and to get a simple overview of the satellite's status. The beacon data contains a small subset of telemetry data that is transmitted periodically in Morse code. The HPTM is used for transmitting large amounts of mission data. This consists of telemetry data from each subsystem and the experiment data, for example a picture taken by the camera. HPTM is turned on only after receiving a certain telecommand. The main goals of the current work were to: analyze other CubeSat projects beacon implementations; analyze requirements for ESTCube-1 beacon; determine optimal parameters for ESTCube-1 beacon (output power, transmission period, modulation, beacon data, operating frequency); propose a beacon design for ESTCube-1; analyze operational risks of the beacon design; develop beacon radio frequency (RF) electronics prototype; measure the output parameters of the prototype (signal purity, signal strength, on/off signal ratio. The work consists of ten Chapters. In Chapter 4, an overview of other CubeSat projects beacon implementations is given to see different solutions that are currently operational on orbit. Chapter 5 describes ESTCube-1 satellite in more detail with focus on COM subsystem. Chapter 6 analyzes requirements for developing a satellite beacon. Based on that analysis a beacon design is proposed in Chapter 7. Chapters 6 and 7 form the main body of the work. Chapter 8 describes the beacon radio frequency electronics prototype development and measurement analysis. In Chapter 9, the results of this work are discussed and future activities are proposed. In Chapter 10, most important of these results are concluded and the completion of goals is assessed.