• INEXPENSIVE UHF TRANSCEIVER LEVERAGING COTS COMPONENTS

      Kosbar, Kurt; Chiaventone, Owen; Avola, Kyle; Tuschhoff, Stetson; Missouri University of Science and Technology (International Foundation for Telemetering, 2017-10)
      This paper describes the design of an inexpensive UHF transceiver which leverages some of the recently developed commercial off-the-shelf (COTS) components. The initial goal is to implement digital voice transmit and receive function, although the design can accommodate a wide range of digital communication and telemetry applications. The handheld transceiver transmits 5 watts of power in the 430-435 MHz UHF band. A 1.2 kHz wide GFSK modulation format is used, generated by a Silicon Labs radio chip. The recently released Raspberry Pi Zero processor implements a low bit rate audio coding which conforms to the Codec2 standard. The transceiver fits in a 3 cm x 8 cm x 14 cm volume. It is powered by two 18650 lithium ion cells, and draws approximately 1 watt of power during receive, and 6 watts during transmission.
    • PERFORMANCE EVALUATION FOR DECISION-FEEDBACK EQUALIZER WITH PARAMETER SELECTION ON UNDERWATER ACOUSTIC COMMUNICATION

      Nassr, Husam; Kosbar, Kurt; Missouri University of Science and Technology (International Foundation for Telemetering, 2017-10)
      This paper investigates the effect of parameter selection for the decision feedback equalization (DFE) on communication performance through a dispersive underwater acoustic wireless channel (UAWC). A DFE based on minimum mean-square error (MMSE-DFE) criterion has been employed in the implementation for evaluation purposes. The output from the MMSE-DFE is input to the decoder to estimate the transmitted bit sequence. The main goal of this experimental simulation is to determine the best selection, such that the reduction in the computational overload is achieved without altering the performance of the system, where the computational complexity can be reduced by selecting an equalizer with a proper length. The system performance is tested for BPSK, QPSK, 8PSK and 16QAM modulation and a simulation for the system is carried out for Proakis channel A and real underwater wireless acoustic channel estimated during SPACE08 measurements to verify the selection.
    • PERFORMANCE OF IEEE 802.11S FOR WIRELESS MESH TELEMETRY NETWORKS

      Kosbar, Kurt; Zawodniok, Maciej; Price, Nathan D.; Chandran, Arul Mathi Maran; Missouri University of Science and Technology (International Foundation for Telemetering, 2017-10)
      Wide area sensor networks have numerous agricultural, industrial, scientific, medical, and military applications. For many years now, such networks have been implemented through wireless mesh networks. As wireless mesh networks have come to maturity, several network standards have become readily available. The WiFi mesh extension 802.11s was finalized in 2008 and officially adopted into the 802.11 standard in 2012, is extremely interesting thanks to the wide spread adoption of WiFi and low cost. In this paper, we evaluate the performance of a small 802.11s net-work implemented on low-cost, off-the-shelf single board computers for the purpose of building a telemetry sensor network.
    • Permanent Magnet Synchronous Motor Variable Frequency Drive System

      Kosbar, Kurt; Schad, Judah; Nichols, Cameron; Brinker, Katelyn; Missouri University of Science and Technology (International Foundation for Telemetering, 2017-10)
      This paper discusses a permanent magnet synchronous motor (PMSM) variable frequency drive (VFD) system developed for an all-terrain Wifi-HaLow connected (802.11ah, 900 MHz) modular electric vehicle that competed in the Mars University Rover Challenge (URC). The quadrature axis flux linkage for each motor was estimated using on-board voltage and current measurements. A synchronous control algorithm tracked the electromagnetic operating parameters, which are highly dependent on variations in motor construction and load conditions. A feed-forward model-driven observer solution calculated flux linkage angles by direct-quadrature-zero transformation of three-phase shunt currents using DSP processors.
    • POWER TELEMETRY ONBOARD A SEMI-AUTONOMOUS MARS ROVER

      Kosbar, Kurt; Mormile, Melanie; Marcolina, Rebecca C.; Osibodu, Olugbenga O.; Missouri University of Science and Technology (International Foundation for Telemetering, 2017-10)
      This paper explores the telemetry of the power distribution system utilized onboard a semi-autonomous Mars rover. The Missouri S&T Mars Rover Design Team designs and fabricates such a rover to compete in the University Rover Challenge, a competition whose tasks simulate a future manned mission to Mars. To maximize efficiency during competition, the rover’s modular power distribution system consists of three separate units: a 72 Watt-hour, Lithium-polymer battery pack; a custom Battery Management System (BMS); and a central power board. The BMS and power board measure and process electrical and environmental data autonomously, creating a self-regulating system onboard the rover. The two also form a communication chain between team teleoperators and the battery pack. This continuous stream of real-time data enables the team to quickly monitor the rover’s safe operation, to make informed decisions during competition, and to apply this data to the design of future power systems.