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Feliciano, WalberDesign and Implementation of a Radiometer and Rain Data Collection System for a Ka-band LEO Ground Station
Master of Science, University of Akron, 2009, Electrical Engineering
The design and performance of broadband Ka-band satellite communication systems depends mostly on the radio propagation characteristics of the earth-to-space path. The goal of this project was to develop and deploy a low earth orbit (LEO) ground station terminal capable of collecting radiometric and beacon data at Ka-band frequencies; which ranges approximately from 20 to 30 GHz. LEO satellites will employ high data rates to transfer very large amounts of data. High data rates require large channel bandwidth; a motivation to utilized Ka-band frequencies. Many radio frequency (RF) propagation effects are more severe at Ka-band frequencies than at lower frequencies. Collected data can be statistically analyzed and used to study the Earth’s atmosphere RF propagation effects at Ka-band, applicable to LEO links; thus improving the system availability models currently used. Collection of propagation data and its analysis is important for the development of satellite link analysis and communication component design, capability and requirements. Currently no LEO attenuation prediction models are available at Ka-band. This project provides a starting point to understand the dynamic effects of the Earth’s atmosphere on rapidly changing Ka-band transmission from a LEO spacecraft. A LEO propagation model will enable communication system designers to improve their systems availability.

Committee:

Nathan Ida, PhD (Advisor)

Subjects:

Electrical Engineering

Keywords:

LEO;Ka-band;Propagation;Ground Station;Radiometer

Labarowski, Daniel DouglasWireless Personnel Tracking in Confined Quarters
Master of Science (M.S.), University of Dayton, 2017, Electrical and Computer Engineering
A variety of industrial, public service, and government occupations would benefit from a personnel tracking system capable of precisely tracking personnel working mixed indoor / outdoor worksites. Such a system would increase the safety and efficiency of personnel working these sites, especially in the case of critical operations such as public service. No currently available systems fit the needs of this application. A field deployable system is defined herein that specifically addresses the needs of tracking personnel working small area indoor / outdoor environments. The Theseus tracking system is a two part system composed of a ground station deployed at a work site and one or more Radio-Frequency Identification (RFID) beacons deployed with personnel assigned to the work site. The ground station emits a Frequency-Modulated Continuous-Wave (FMCW) pulse that the beacons echo and return to the ground station. The ground station uses tracking / radar algorithms to discern the distance and direction to the RFID beacon. For a finalized system, elevation tracking would be included as well. Particular focus is given to the RFID beacon as the researcher’s efforts were directed predominately at this device. The RFID beacon is a bent-pipe transceiver, meaning that any signal received is re-transmitted at a slightly different frequency. The RFID beacon has evolved several times during the duration of this project due to system level changes, and in its current form it transmits and receives within a narrow band between 420 and 450 MHz that the Federal Communications Commission (FCC) has allocated to tracking systems. The narrow gap between transmit and receive frequencies has placed taxing requirements on the filtering used in the RFID beacon. A Surface-Skimming Bulk Wave (SSBW) filter was specified to meet the tight requirements of the RFID beacon, but was not procurable for the proof of concept. In the place of these filters, the proof of concept incorporates an Intermediate-Frequency (IF) filtering scheme as well as accommodations to add manually tuned coaxial cable filtering. Potential antennas, enclosures, and power sources are also discussed. Remaining efforts to validate the system have been identified. Future work that could make this system cheaper as well as more robust and reliable has been identified. These efforts range from simplifying the RFID beacon and trimming its production costs to expanding the functionality of the RFID beacon and potentially integrating the beacon with existing communication equipment using intelligent Software Defined Radio (SDR) systems. The current Theseus system provides a solution to tracking personnel working small area indoor / outdoor work sites not currently rivalled by existing products. Additional research should be considered that may produce more robust solutions.

Committee:

Michael Wicks, Ph.D. (Committee Chair); Guru Subramanyam, Ph.D. (Committee Member); Andrew Bogle, Ph.D. (Committee Member)

Subjects:

Electrical Engineering; Engineering

Keywords:

wireless; personnel; tracking; confined; quarters; radar; RFID; direction finding; Theseus; beacon; ground station; system