Keshmiri, Shawn; Hauptman, Dustin; Shukla, Daksh; Blevins, Aaron; University of Kansas, Electrical Engineering & Computer Science Department; University of Kansas, Department of Aerospace Engineering (International Foundation for Telemetering, 2018-11)
      Swarms of autonomous unmanned aerial systems (UASs) are becoming increasingly popular as efficient replacement for manned aircraft. The major component that makes the swarm of UASs possible is an efficient exchange of aircrafts states (e.g. position & velocity) for all agents and the ground station. Advanced communication technologies are required to be implemented on each agent to enable real-time communication at high frequencies (e.g. 20 Hz) to avoid inter collisions and holding formations. To assess mesh network limitations and to identify bottlenecks, a series of simulations are carried out using actual hardware that is used for swarms of UASs, which are: (1) Amount of bandwidth that can be guaranteed given the communication system being used (XBee-900HP), each plane that the KU team uses, transmits 127 variables, 4 bytes each, at 20 Hz which means each plane needs 10 KBps and the mesh network might be able to support 53 UASs theoretically (2) Range limitations (3) Latency issues.
    • Remote Monitoring of Forces on Head for Detection of Traumatic Brain Injuries on Amusement Park Rides

      Camp, Laura; Marcellin, Stephanie; Rickel, Jodi; Rubenow, Tierny; Univ Arizona, Dept Elect & Comp Engn (International Foundation for Telemetering, 2018-11)
      The ASTM F24 Committee pays substantial attention to the potential safety risks that roller coasters pose to riders. Although the G-forces exerted on rides are strictly controlled to prevent traumatic brain injury and other conditions, operators may wish to monitor the impact forces guests experience to determine if they need to be removed from the ride. We have designed a system to monitor data and relay the findings to the operators. To measure the effect roller coasters have on the brains of guests, we used a combination of gyroscopes, accelerometers, and impact force sensors are incorporated into a headpiece worn by the guest. During the ride, the sensor data is wirelessly transmitted to a base station where it can be monitored in real time by an operator. The system compares the gathered data with limits based on pre-existing research on traumatic brain injuries, and then alerts the operator to potential issues.

      Alam, Tasmeer; Moazzami, Farzad; Dean, Richard; Morgan State University, Department of Electrical and Computer Engineering (International Foundation for Telemetering, 2018-11)
      This paper includes the design, modeling and analysis of the aeronautical channel which includes the dynamics of flight simulation. For any given flight path scenario in the cruise state it is well understood that the channel is fitted by a 2 ray model. The dynamics of this model can be generated using the two-ray ground reflection model which is based on the position, velocity, and direction of the aircraft. The dynamic aeronautical channel model includes Doppler shift and delay spread for each path of a channel model. This paper shows how each parameter is created for modelling the dynamic channel. The design of such channel model will help the telemetry community to incorporate channel dynamics in computer simulation to improve the accuracy of flight simulation in the design and pre-test stages. Further, it can provide insight to the selection of modulation, equalization and coding for such channels.

      Du, Xianyu; Zhou, Yi; Yi, Xiaoqian; Instrumentation Department, COMAC Flight Test Center (International Foundation for Telemetering, 2018-11)
      In order to cover the complete flight path of a large civil aircraft during its flight test missions, Telemetry-over-IP (TMoIP) systems have become a standard technique solution in COMAC Flight Test Center. In this paper, practical considerations in implementing the TMoIP systems using a satellite communication link will be discussed, along with the applicable satellite modem parameters. Based on the Command & Control Center located besides the Shanghai Pudong International Airport, several typical cities represent different directions and climatic conditions across the mainland of the country are analysed. Thanks to the high mobility and rapidly deployable satellite communication vehicle, and the rental of satellite time can be specified in contract at a reasonable price and scheduling can be coordinated a short time in advance, high-risk flight test subjects can be monitored and instructed at the head-quarter where more specialist can participate and better ground test and verification equipments can be arranged to support the missions.

      Baxter, Jason; Perrins, Erik; DePardo, Dan; University of Kansas, Electrical Engineering & Computer Science Department (International Foundation for Telemetering, 2018-11)
      Due to the economic importance of spectrum allocation, modulation schemes traditionally used in telemetry are being replaced with more spectrally efficient schemes. Amplitude and Phase Shift Keying (APSK) is one modulation scheme being considered for implementation in aeronautical telemetry. However, an APSK modulated signal is vulnerable to nonlinearities of a transmitter’s RF power amplifier (PA). Driving a PA into saturation produces two undesired nonlinearities: amplitude-to-amplitude modulation (AM-AM) and amplitude-to-phase modulation (AMPM). This paper characterizes the PA in a C-Band transmitter using a 16-APSK test signal in terms of these nonlinearities.

      Fung, Eddie; Johnson, William H.; Kogiantis, Achilles; Rege, Kiran M.; Perspecta Labs (International Foundation for Telemetering, 2018-11)
      High Doppler shifts between base stations and test articles (TAs) pose the biggest problem to Aeronautical mobile telemetry (AMT) implemented on a wireless LTE network. Our solution to this problem includes a Doppler estimator/compensator (DEC) that proactively shifts the LTE uplink (LTE UL) signals transmitted by the TA. We have designed the DEC in the form of an applique’ that can be inserted between the transmit/receive ports of a COTS TA transceiver and its antenna(s). The DEC estimates the Doppler shift using the LTE UL signals transmitted by the TA, which carry a frequency offset that includes the Doppler shift. This not only provides a clean, noise- and fading-free signal for Doppler estimation, but also allows us to do away with the need to know the identity of the base station with which the TA is communicating. In this paper, we provide an architectural description of the DEC and an outline of the algorithms that have been incorporated into it. At present, a laboratory prototype of the DEC has been developed using Universal Software Radio Peripherals (USRPs), coupled with a Linux PC to carry out most of the computations. An FPGA-based implementation is currently under development.

      Thom, Gary A.; GDP Space Systems (International Foundation for Telemetering, 2018-11)
      Today’s telemetry ground stations are migrating from traditional serial PCM data distribution to Telemetry over IP architectures. The Range Commanders Council has published IRIG 218-10 TELEMETRY TRANSMISSION OVER INTERNET PROTOCOL (TMoIP) STANDARD, which attempts to standardize PCM distribution over IP networks and is currently working on a revision. Ranges have begun investigating new TMoIP systems. This paper attempts to facilitate this migration by discussing the TMoIP, networking and architectural concepts that need to be considered when deploying a TMoIP system. The paper draws on the lessons learned over the previous 10 years of designing, installing, troubleshooting and optimizing telemetry data distribution over IP networks. It discusses the critical component and architectural decisions to be made and some of the pitfalls to be avoided.

      Oyediran, David; Dean, Richard; Moazzami, Farzad; Morgan State University, Department of Electrical and Computer Engineering (International Foundation for Telemetering, 2018-11)
      Spectrum sharing between federal and commercial users is proposed by the FCC and NTIA to open up the 3.5 GHz band for wireless broadband use. This requires the detection and subsequent allocation of available licensed spectrum for temporary use by other users without interfering with incumbent signal transmission. The DoD has a documented requirement of 865 MHz by 2025 to support telemetry but only 445 MHz is presently available. This paper presents spectrum sharing opportunity and technology that will help reduce service interference between spectrum users. We developed protocol model for spectrum sharing and implemented cognitive radio media access sensing mechanism using cyclostationary feature detector (CFD). The paper demonstrates shared usage by secondary users with minimum interference and improvement in throughput by as 5 times compared to other protocols. This is an introductory work that shows the feasibility of the approach with the potential for many other factors to be considered. We suggest that with proper sensing mechanism and quiet period implementation by the unlicensed users, CSMA/CA RTS-CTS could be adopted for licensed user protection.

      Hegde, Vinayak; Nokia Corporation of America (International Foundation for Telemetering, 2018-11)

      Brown, Jason R.; Rohrer, Justin P.; Naval Postgraduate School, Department of Computer Science (International Foundation for Telemetering, 2018-11)
      Drone swarms pose a particular challenge to telemetry networks, due to the number of airborne nodes involved, and their potential to overwhelm the available bandwidth on the communications channel with simultaneous telemetry streams. Previously, we saw that mobile ad-hoc (MANET) routing protocols could exacerbate this issue by flooding the network with routing-control packets. In this work we model the Naval Postgraduate School fixed-wing drone swarm and compare the performance of several disruption-tolerant networking (DTN) routing protocols designed to address these challenges.
    • Telemetry System Based on MESH Network and Its Application

      Guo, Pingfan; Liu, Ming; Li, Hong; Zhu, Hongxiang; Chinese Flight Test Establishment (International Foundation for Telemetering, 2018-11)
      In the flight test, the advantages of network telemetry have gradually emerged, and their application fields will also be expanded. This paper introduces a network telemetry system based on MESH net and its application in flight test, a ground station can receive telemetry signals of several planes at the same time; the components and functions of the system are described, the advantages of this network telemetry system, existing problems and suggestions on future improvements are presented.

      Kovach, Bob; IPtec, Inc. (International Foundation for Telemetering, 2018-11)
      The efforts to implement the distribution of real-time information streams via IP packet-based networks in the range environment have largely utilized the recovery of timing information via implicit techniques, such as adaptive clock recovery. These techniques allowed the alignment of streams with disparate delay characteristics to accuracies on the order of 1 millisecond. With the availability of techniques to distribute high accuracy timing information to network nodes, the capability to recover and align real time streams on the order of microseconds is possible. This paper will focus on a methodology to perform precision stream alignment that utilizes timestamping and the IEEE 1588 Precision Time Protocol (PTP) as a clock source. IEEE 1588 is currently utilized in cellular networks to deliver synchronization to remote network elements, providing superior accuracy and stability. The paper will review expectations for performance and discuss considerations in system level design to optimize timing distribution performance and ultimately stream alignment accuracy. System elements and their effect on performance will be identified and characterized. Finally, a TM Gateway implementation example which utilizes PTP coupled with hardwareassisted timestamping techniques to align recovered TM streams to a high degree of accuracy will be described. Real world results for clock accuracy and expectations for stream alignment accuracy will be shared.

      Harrison, Willie K.; Nelson, Kaela; Dye, Scott; BYU, Department of Electrical and Computer Engineering (International Foundation for Telemetering, 2018-11)
      In this paper, we investigate the application of physical-layer security coding for next generation aeronautical telemetry communication systems. The coding we refer to is similar to error-control coding, but the codes are deployed for two purposes: to achieve reliable communications, and to achieve secure communications. We consider a single eavesdropper on an air-to-ground aeronautical telemetry link, and show how the overhead measured by the rate of the code can be used to keep secrets from eavesdroppers over noisy channels, rather than recover from channel errors. We show simple examples that work over erasure channels to achieve a security constraint, and then consider approaches to more practical coding constructions for Gaussian channels that satisfies both reliability and security constraints on the network.

      Reinwald, Carl; Laulima Systems (International Foundation for Telemetering, 2018-11)
      The telemetry network revolution takes aeronautical flight testing from a broadcast-only paradigm to a TM-data-on-demand paradigm. This paper explores this paradigm shift, focusing on fundamental architectural changes enabled by incorporating telemetry networking technologies into a flight test system. Two concepts are presented to help understand the TM-data-on-demand paradigm: retrieving and processing recorded data from a test article during a mission and onboard dynamic data analysis and compression. An example flight test system with both SST and TmNS components provides a foundation to further explore the paradigm-shifting capabilities a telemetry network brings to flight test. In addition to TM-data-on-demand, the current static spectrum allocation methodology must also be replaced with a more agile, bandwidth-on-demand paradigm. When both TM-data-on-demand and bandwidth-on-demand capabilities have been realized, a new era of efficient flight testing will emerge.

      Graham, Richard A. Jr. (International Foundation for Telemetering, 2018-11)
      Several telemeters output RNRZ-L. This paper examines how to use software to decode the RNRZ-L to NRZ-L.
    • Progress in the Migration of Flight Test Analysis Routines to Python

      Bretz, John C.; Symvionics, Inc., IADS® Development Group (International Foundation for Telemetering, 2018-11)
      In recent years, the Python language and its associated scientific libraries have been enjoying increasing acceptance. Scientific Python’s ability to replace MATLAB® for many disciplines makes its consideration as an alternative imperative. Python is popular in the engineering academic arena; many entry-level Engineers have experience coding engineering tools in Python already due to its open-source nature and status as a low-cost, low-risk alternative to MATLAB. The IADS Development Group (IDG) has been working on uses of Python and ways to allow users to write Python code from within IADS to help streamline their data processing efforts. This paper will document the progress made since 2015. Experience gained with some of the available Python libraries will be shared, and various tools that have been developed in Python by IADS programmers for their users will be introduced and described in detail. An attempt will also be made to assess the acceptance of Python in the Flight Test community.
    • Homing and Docking Algorithms for Circular Transmission and Receiver Arrays

      Radzicki, Vincent R.; Hua, Lee; Univ California Santa Barbara, Department of Electrical and Computer Engineering (International Foundation for Telemetering, 2018-11)
      Homing and docking are two major components in the navigation of UAV’s and UUV’s. It involves the estimation of the six-element displacement vector based on the received signals, where three of the vector elements are associated with the translational displacement and the other three are for the rotation vector. The homing procedure is based on the estimation of the rotation vector with far-field approximations. In the docking range, the displacement estimation becomes more sensitive and critical. Far-field approximation-based algorithms are no longer effective, and high-precision techniques become important and need to be developed. In this paper, we examine and model the multi-dimensional displacement estimation for circular arrays. It allows us to accurately assess the performance as well as the limitation of the algorithms, with respect to various system parameters such as the size of the arrays, range distance, transmitted waveforms, and signal processing algorithms.

      Rubio, Pedro; Alvarez, Jesus; AIRBUS DEFENCE & SPACE Flight Test (International Foundation for Telemetering, 2018-11)
      Pan&Tilt directional antennas are present in every Airspace Test Center. They are used to receive telemetry data from the target in test (usually a rocket or an aircraft). Required telemetry range can be usually around 200nm which leaves no option but to use directional antennas (parabolic among others). The use of directional antennas greatly enhances the telemetry range by a factor of 1000. But it does it at a cost: directional accuracy. This kind of antenna has a narrow radiation pattern with its nominal gain at the center of the antenna dish. The main beam of the radiation pattern can be as narrow as 1.8 degrees (3db) in a C Band 2.4m parabolic antenna. An antenna has to be pointing its radiation pattern main lobe to the flying target with an error of less than the main lobe width in order not to degrade reception. A method has been implemented to properly calibrate the mechanical pointing vector to overlap with the radiation pattern main lobe. The calibration method presented in this paper allows a very precise calibration that can be performed locally with the aid of DGPS, RF Beacon, RF Spectrum Analyzer and software to manage the whole process.

      Bauer, William; Mann, Phillip; Raytheon Missile Systems (International Foundation for Telemetering, 2018-11)
      Traditional Decom Systems usually require vendor specific data descriptions and provide vendor specific processing capabilities. Using a Software Decom allows the Decom hardware to be setup with a minimal configuration. The added capability of a UDP Multicast over Ethernet for the framed decommutated data allows for common Applications to perform the heavy lifting of Archiving, Real Time Display, and Distributed Processing. Any PC listening on the Local Area Network can access the telemetry data in real-time. This allows common real-time displays, archival tools and data forwarding applications to all run simultaneously.

      Shea, Donald; Applied Antenna Technology (International Foundation for Telemetering, 2018-11)
      The coaxial waveguide antenna exhibits efficient multi-band operation in both tracking and nontracking applications. Radiation from coaxial waveguide operating in the TE1,1 mode produces an on-axis pattern similar to that of open-ended circular waveguide. A second mode, the TE2,1 mode, produces a difference pattern similar to that of a four arm spiral. An inner waveguide cavity operating in the TE1,1 mode and a concentric outer waveguide cavity simultaneously operating in the TE2,1 mode provides this antenna the ability to operate as a tracking feed. It is the intent of this paper to show how the coaxial waveguide antenna is ideally suited to meet many of today's antenna system requirements.