• 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.

      Hedge, Vinayak; Nokia Networks (International Foundation for Telemetering, 2017-10)
      Cellular based Range Telemetry provides a lot of benefits over legacy Aeronautical Mobile Telemetry, such as: • Higher capacity, allowing multiple test articles (i.e. telemetry radio links) which have active telemetry data measurements exchanged in near real time. • Bi-directional radio links, that can allow new signaling with the avionics equipment on the test articles. • Higher performance provided by spectrally efficient OFDMA waveform used in LTE and the dynamic link adaptation that is built into the LTE waveform. With the CRTM cellular approach, the overall range coverage area is broken into multiple coverage areas, each served by a single cell. To maintain seamless service throughout the test flight, CRTM must support seamless mobility as the aircraft moves between the coverage areas of these cells. This is achieved using the connected mode handover procedures supported by LTE technology. Traditional LTE networks rely on signal strength measurements made by the User Equipment (UE) to make handover decisions. The measurement system and handover procedures have been designed to support mobility at speeds under 500 km/hr. To support mobility at higher speeds, the following need to be taken into account: - LTE User Equipment (UE) RF Signal Measurements: Accuracy of measurements depends on UE’s capability to measure the signal strength of a neighbor cell while synchronized to its serving cell. The higher Doppler shifts expected in an AMT environment due to the higher test article speeds and the higher frequency of operation along with the difference in Doppler shifts between the serving cell and neighbor cells complicates cell measurements. - Handover Processing Time: The serving eNodeB needs to process the measurements from the UE and initiate handover in a timely manner. Delays in handover processing can result in radio link failures. The higher speeds of test articles in the AMT environment reduces the time available to the eNodeB for handover processing. This paper explains the handover procedure in 4G LTE, with the focus on: Measurement reports that support handover decisions Decisions impacting data service delays during handover impacts to the handover processing when the UE (i.e. test article in CRTM) is moving at very high speed.

      Blanc, Grégory; Skrzypczak, Alexandre; Pierozak, Jean-Guy; ZODIAC AEROSPACE - ZODIAC DATA SYSTEMS (International Foundation for Telemetering, 2017-10)
      The emission of the telemetry signal is required over minimum two different antennas to keep the telemetry link available during a maneuver of a flying object. If nothing is made at the transmitter side, the telemetry link can be fully lost as both signals may have an opposite phase. This is the well-known “2-antennas problem”, also known as the “porcupine effect”. In 2016, Zodiac Data Systems (ZDS) presented a pragmatic and cost effective concept named eXtended Time Diversity (XTD) which is dedicated to combat the porcupine effect. The efficiency of this concept was demonstrated through lab tests, as well as its robustness in presence of multipath. The goal of this paper is to present the performance of the Extended Time Diversity in real conditions, after a series of flight tests.
    • Telemetry Range Support Aircraft (TRSA) Program Providing the Navy with Next Generation TM and Range Support

      Roudebush, J. Kyle; Hernandez, Jose; Kujiraoka, Scott; Sanchez, Kenneth; NAVAIR (International Foundation for Telemetering, 2017-10)
      The aircraft currently being used to support the Navy’s mission of Telemetry Reception, Range Safety as well as Range Surveillance/Clearance are reaching the end of their useful life. As a result, there are ongoing efforts to procure a new aircraft and integrate these mission systems in order to continue the support of critical Naval Test Range operations. This paper will detail the current efforts being undertaken to upgrade a Gulfstream 550 to perform Range Support missions for the Multi-service Government Test Ranges.
    • Data Security Architecture Considerations for Telemetry Post Processing Environments

      Kalibjian, Jeff; DXC Technology Company (International Foundation for Telemetering, 2017-10)
      Telemetry data has great value, as setting up a framework to collect and gather it involve significant costs. Further, the data itself has product diagnostic significance and may also have strategic national security importance if the product is defense or intelligence related. This potentially makes telemetry data a target for acquisition by hostile third parties. To mitigate this threat, data security principles should be employed by the organization to protect telemetry data. Data security is in an important element of a layered security strategy for the enterprise. The value proposition centers on the argument that if organization perimeter/internal defenses (e.g. firewall, IDS, etc.) fail enabling hostile entities to be able to access data found on internal company networks; they will be unable to read the data because it will be encrypted. After reviewing important encryption background including accepted practices, standards, and architectural considerations regarding disk, file, database and application data protection encryption strategies; specific data security options applicable to telemetry post processing environments will be discussed providing tangible approaches to better protect organization telemetry data.

      Newton, Todd A.; Roberts, Christopher J.; Fletcher, Gregory G.; Rossiter, Daniel S.; Southwest Research Institute®; NASA Goddard Space Flight Center (International Foundation for Telemetering, 2017-10)
      The Space Mobile Network (SMN) is NASA’s next generation architecture concept for communications services between ground and space-based assets. The SMN calls for a paradigm shift in space communications. The transition will move from an approach based on static, preplanned communications over point-to-point channels to a dynamic, event-driven, and network-based approach that facilitates service-oriented communications. In doing so, the SMN is able to leverage some concepts and technologies present in today’s terrestrial wireless networks, while others must be extended or adapted to the space communications domain. This paper provides background on key SMN architectural concepts and an evaluation of the suitability of terrestrial wireless network modeling tools to be used and applied for proving out SMN concepts.

      Rice, Michael; Josephson, Chad; Perrins, Erik; BYU, Dept Elec & Comp Eng; Univ Kansas, Dept Elec Eng & Comp Sci (International Foundation for Telemetering, 2017-10)
      This paper investigates the application of 16-APSK modulation to aeronautical mobile telemetry. The peak-to-average power ratio vs. code rate tradeoff is mapped to an optimization problem involving spectral efficiency and the constellation parameters. The optimization results produce a theoretically optimum solution that is 3.95 times more spectrally efficient as uncoded SOQPSK-TG. When implementation losses and the available IRIG 106 LDPC code rates are factored in, the advantage drops to 3.20 times the spectral efficiency of SOQPSK-TG.

      Marcellin, Michael; Boyer, Kyle; Brubaker, Laura; Everly, Kyle; Herriman, RIchard; Houston, Paul; Ruckle, Sean; Scobie, Rory; Ulanday, Ian; Univ Arizona (International Foundation for Telemetering, 2017-10)
      The University of Arizona Baja Racing Team competes annually in an intense off-road racing competition. This year’s car features a distributed sensor network capable of displaying useful data to the driver, the benefits and technical aspects of which are examined by this paper. Based on the ATmega2560 chip, the system is USB programmable, features hot-swappable batteries, and includes SMD components. Each sensor is custom designed, functions as an I2C slave, and contains its own ATtiny85 microcontroller allowing all the sensors to be addressable and enables them to be wired in parallel. The system also includes interrupts for almost every single sensor, which allows for more accurate data collection and guarantees that no important data will be missed. A custom-made board was created to connect these sensors and serve as a microcontroller data logger based on an Arduino reference design.

      Geoghegan, Mark; Schumacher, Robert; Quasonix (International Foundation for Telemetering, 2017-10)
      Flight test telemetry environments can be particularly challenging due to RF shadowing, interference, multipath propagation, antenna pattern variations, and large operating ranges. In cases where the link quality is unacceptable, applying multiple receiving assets to a single test article can significantly improve the overall link reliability. The process of combining multiple received streams into a single consolidated stream is called Best Source Selection (BSS). Recent developments in BSS technology include a description of the maximum likelihood detection approach for combining multiple bit sources, and an efficient protocol for providing the real-time data quality metrics necessary for optimal BSS performance. This approach is being standardized and will be included in Appendix 2G of IRIG-106-17. This paper describes the application of this technology and presents performance results obtained during flight testing.
    • Mobile Diagnostics for Personal Electrics Transportation Devices

      Prescott, Glenn; Gilchrist, Zachary A.; Univ Kansas, Electrical Engineering Design Laboratory (International Foundation for Telemetering, 2017-10)
      The ultimate purpose of this project was to improve on a new electric form of transportation. These methods of transportation have been gaining popularity for those who have relatively short commutes, and this project poises that group as the target audience. As a result of these trends and the practicality of small personal transportation, the design team made the purpose to attain usable real-world practicality and walking replacement ability. Other types of devices have been created before, however they usually have a short ride time and do not go much faster than the average walking speed. That being said, this design also uses telemetry to serve as a proof of concept that internal data can be sent to a receiver from a distant location. The end result was expected to be an enjoyable experience that gave a mobile diagnostics system.

      Borah, Deva K.; Curry, Elam; New Mexico State University, Klipsch School of Electrical & Computer Engineering (International Foundation for Telemetering, 2017-10)
      Physical layer security techniques have received increasing interests in recent years due to their ability to provide additional security and their ability to be combined with conventional higher layer security measures. One such physical layer security technique is the directional modulation (DM), where the goal is to provide unhindered communication in an intended direction while hindering the communication in unintended directions. In this paper, we study the effect of Rician fading on a system employing a DM technique that minimizes the intersymbol distance in unintended directions. The performance of the system is investigated for varying ratios of the line-of-sight and scattered signal power, or Rician K-factors. The effect of Rician fading on the bit error rate (BER) performance in intended and unintended directions is studied.

      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.

      Xiao, Xin; Vasic, Bane; Lin, Shu; Univ Arizona; UC Davis (International Foundation for Telemetering, 2017-10)
      Low-density parity-check (LDPC) codes with column weight-4 are widely used in many commu-nication and storage systems. However, traditional hard decision decoding algorithms such as the bit-flipping (BF) algorithm suffer from error floor due to trapping sets in LDPC codes. In this paper, to lower error floor of the BF algorithm over the Binary Symmetric Channel (BSC), we design a set of decoding rules incorporated within the BF algorithm for column weight-4 LDPC codes. Given a column weight-4 LDPC code, the dominate error patterns of the BF algorithm are first specified, and according to the designed rules, additional bits at both variable nodes (VN) and check nodes (CN) provide more information for the BF algorithm to identify the dominate error patterns, so that the BF algorithm could deliberately flip some bits to break them. Simulation results show that the modified BF algorithm eliminates all 4-error patterns and lowers the Bit Error Rate (BER) for at least two orders of magnitude with a trivial increment of complexity.
    • Modeling and Simulation with Numbers!

      Guadiana, Juan; Baird, James; Tackill, Curtiss; Telemetronics Inc.; Blue Origin LLC. (International Foundation for Telemetering, 2017-10)
      Moore's Law predicts the trends in our technology very well and we have witnessed the relentless march of software solutions deep into the hardware domain. Link models are normally in the realm of scientific software packages like Mathematica, MatLab or Satellite Tool Kit. Here we apply Frii's Transmission equation to perform a link model with a common application like Numbers or Excel. Modeling a single link is easy and a staring antenna Array is modeled as many single links. Creating the model does require planning just as creating any software application does, but the "coding" is fairly straight forward. The results are stunning graphical plots. A simulation is created from the same spread sheet depicts the array's Graphics User Interface (GUI). Very low cost, an excellent way for students to learn to model and simulate their systems. The work serves as a good prototype to experiment with before investing in expensive software or software development. Spreadsheets do break easily so plan to back up your sheets periodically.

      Huang, Jie; Kosbar, Kurt; White, Julia; Department of Electrical and Computer Engineering, Missouri University of Science and Technology (International Foundation for Telemetering, 2017-10)
      Optic fiber sensors are employed in a variety of applications for the remote measurement of various parameters such as strain, pressure, or temperature. These sensors offer an array of benefits as well including light weight, compactness, and high resolution. In particular, Fabry-Perot interferometers (FPIs) maintain these benefits and can also be made to withstand extremely high temperatures. This advantage of the FPI allows it to be used in harsh environments where many other tools for parameter measurement could not survive. An FPI strain sensor is constructed and tested which has the capabilities to be used at high temperatures of over 1000°C for applications in gas turbine engine testing. This paper discusses the need for high temperature strain sensors in engine testing and this sensor’s capabilities in this application.

      Rohrer, Justin P.; Pospischil, Alexis; Department of Computer Science, Naval Postgraduate School (International Foundation for Telemetering, 2017-10)
      In 2015, a group of Naval Postgraduate School (NPS) professors and students set the record for largest fixed-wing unmanned aerial vehicle (UAV) swarm flown at one time. The swarm had 50 vehicles flying simultaneously and successfully demonstrated distributed decision-making with all processing occurring on swarm vehicles rather than a centralized control station. Much of the decision-making is based on telemetry data that is continuously streamed from all the nodes. At that time all telemetry data was broadcast in a single-hop radio environment using 802.11 in AdHoc mode. In the future, drone swarm distribution and mobility patterns will necessitate multi-hop communications for this telemetry data. This paper models the network currently used by the NPS drone swarm as well as potential future topologies and evaluates candidate multihop routing protocols for this application.

      Afran, Md. Shah; Saquib, Mohammad; Rice, Michael; The University of Texas at Dallas; Brigham Young University (International Foundation for Telemetering, 2017-10)
      This paper investigates the performance of sparse minimum mean squared error (MMSE) equalizer for generalized time-reversed space-time block codes (GTR-STBC) in aeronautical telemetry. GTR-STBC equipped with MMSE equalizer performs the best trade-off between the signal-tonoise ratio and inter-symbol interference by allocating unequal power over aeronautical telemetry channels. However, aeronautical telemetry channels are in general consists of larger delay spreads which make the MMSE equalization of aeronautical channels with GTR-STBC computationally complex. Interestingly enough, in spite of larger delays aeronautical channels are made of few sparsely distributed multipaths and therefore their MMSE equalizers are highly compressible. In this paper, compressed sensing based greedy algorithm is used for the design of sparse MMSE equalizer and a convex curve-fitting algorithm is used to find the sub-optimum power allocation parameter at the same sparsity level for GTR-STBC. Our simulation results show that 75-90% of the non-zero equalizer taps can be reduced with a slight relaxation of the mean-squared error (or equivalentlyslight degradationof bit-errorrate performance). It isalso observedthat the optimum transmitter power profile for the sparse MMSE equalizer is different than that of the non-sparse equalizer.
    • International Telemetering Conference Proceedings, Volume 53 (2017)

      International Foundation for Telemetering, 2017-10

      Lotterio, Marco; Luongo, Stephanie (International Foundation for Telemetering, 2017-10)
      Due to the limited availability of L Band spectrum for non-government use, the National Test Pilot School (NTPS) has implemented a C Band airborne mobile telemetry (AMT) datalink system in order to continue to fulfill its mission to educate and train military and civilian flight test personnel. Instrumented aircraft were upgraded to support a PCM stream with higher resolution data and higher data rates required during performance & flying qualities and loads & flutter testing. This technology upgrade included a ground system that was both L and C Band capable and used a Smartronix Telemetry Receiver Processor to convert RF-to-IRIG Chapter 10 UDP packets for a direct input to an IADS® server in the NTPS control room. To achieve the similar performance to the legacy L Band datalink, a high gain, C Band antenna and low noise amplifier were installed as well as a new antenna rotator that allowed for higher precision movements and 360-degree continuous rotation in the pan axis. This paper will discuss the design analyses for and flight testing of the NTPS C Band datalink.

      Jones, Charles H.; Painter, Michael K.; C. H. Jones Consulting, LLC; Knowledge Based Systems, Inc. (International Foundation for Telemetering, 2017-10)
      There is an ongoing need to understand how spectrum is used. In the context of defending T&E use against commercial encroachment, there is a recurring question of how commercial use compares to T&E use. This comparison is complicated by the lack of consistent definitions of the terms “use” and “efficiency” as well as different requirements of these distinctly different applications. The International Telecommunications Union (ITU) recommendations lay out a foundation of spectrum metrics as applied to different applications. The RCC 707 Spectrum Management Metrics Standard provides a T&E perspective. Some insight about commercial metrics can be obtained through an internet search. This paper combines these resources to provide a coherent approach to understanding how to compare spectrum use within these different applications and how this affects the ability to defend against telemetry spectrum encroachment.