• Network System Integration: Migrating Legacy Systems into Network-Based Architectures

      Newton, Todd A.; Moodie, Myron L.; Thibodeaux, Ryan J.; Araujo, Maria S.; Southwest Research Institute (International Foundation for Telemetering, 2010-10)
      The direction of future data acquisition systems is rapidly moving toward a network-based architecture. There is a handful of these network-based flight test systems already operating, and the current trend is catching on all over the flight test community. As vendors are churning out a whole new product line for networking capabilities, system engineers are left asking, "What do I do with all of this non-networked, legacy equipment?" Before overhauling an entire test system, one should look for a way to incorporate the legacy system components into the modern network architecture. Finding a way to integrate the two generations of systems can provide substantial savings in both cost and application development time. This paper discusses the advantages of integrating legacy equipment into a network-based architecture with examples from systems where this approach was utilized.
    • A New Standard for Temperature Measurement in an Aviation Environment

      Grossman, Hy; Teletronics Technology Corporation (International Foundation for Telemetering, 2010-10)
      Accurate temperature measurement is an essential requirement in modern aircraft data acquisition systems. Both thermocouples and Platinum resistance temperature detectors (RTD) are used for this purpose with the latter being both more accurate and more repeatable. To ensure that only the sensor limits the accuracy of a temperature measurement, end-to-end system accuracy forward of the sensor, should be significantly greater than that of the sensor itself. This paper describes a new digital signal processing (DSP) based system for providing precision RTD based temperature measurements with laboratory accuracy in an aviation environment. Advantages of the new system include, true 3-wire RTD measurement, linear temperature output, on-board ultra-precision resistance standards and transparent dynamic calibration.
    • Novel Angle of Arrival Algorithm for Use in Acoustical Positioning Systems with Non Uniform Receiver Arrays

      Lee, Hua; Utley, Christopher; University of California, Santa Barbara (International Foundation for Telemetering, 2010-10)
      Traditional angle of arrival algorithms operate with uniform receiver arrays. Non-uniform arrays typically introduce significant elevation of computation complexity. This paper utilizes the double-integration method for the accurate estimation of the angle of arrival with non-uniform receiver arrays, while maintaining high computation efficiency. Because of the simplicity, the double-integration method is not significantly affected by the increase of the number of receivers or the non-uniform configuration. This approach allows us to perform high-speed high-accuracy estimation of the two-dimensional bearing angle without the constraints of structured receiver arrays, which is important to the realization of real-time tracking of mobile acoustic sources.
    • A Novel Antenna Design for Size Constrained Applications Requiring a Thin Conformal Antenna

      Cirineo, Anthony; David, Rick; Naval Air Warfare Center (International Foundation for Telemetering, 2010-10)
      This paper will discuss the design of a new antenna element for use on vehicles requiring a thin conformal antenna such as on missiles or targets. The new element employs a partial shorted edge, which reduces the size of the element compared to a traditional microwave patch, while maintaining the impedance bandwidth.
    • On the Performance of Spectrally Efficient DPM-OFDMA for Aeronautical Telemetry

      Wylie, Marilynn; Green, Glenn; Gem Direct Inc. (International Foundation for Telemetering, 2010-10)
      In this paper, we discuss CPM-OFDMA (Continuous Phase Modulation - Orthogonal Frequency Division Multiple Access) - a novel modulation that maps a discrete-time CPM into a spectrally efficient DFT-spread OFDMA transmission. Three CPM-OFDMA schemes are developed based on discrete-time variants of PCM/FM, SOQPSK-TG and ARTM-CPM telemetry modulations. Simulations reveal that spectrally efficient CPM-OFDMA schemes can outperform the conventionally defined telemetry schemes in the AWGN environment. For example, maximum likelihood sequence detection of conventional PCM/FM yields a BER of 10⁻⁵ at an E(b)/N(0) of 8:4 dB while the least complex CPM-OFDMA scheme that is based on sampling a PCM/FM waveform once per symbol interval achieves the same BER at an E(b)/N(0) of 7:8 dB. Finally, an extensive search to find a subset of the best performing binary schemes shows that there exist very low complexity schemes that can achieve a BER of 10⁻⁶ at an E(b)/N(0) of 7:8 dB, which is an order of magnitude improvement over the performance of PCM/FM at the same E(b)/N(0).
    • On the Use of Rapid Prototyping for Designing PCM/FM Demodulators in FPGAS

      Rice, Michael; Nelson, Brent; Padilla, Marc; Havican, Jared; Brigham Young University (International Foundation for Telemetering, 2010-10)
      This paper describes the use of an efficient FPGA design flow, called Ogre, developed at BYU to design and implement PCM/FM demodulators. Ogre exploits the notion of reuse by taking advantage of a library of specially designed cores parameterized by XML metadata. A judicious choice of library cores, targeted to signal processing functions common to sampled data modulators and demodulators, reduces the design and test cycle time. We demonstrate this by using the tool to construct rapid prototypes of three different versions of FM demodulators and show that the bit error rate performance is comparable to demodulators on the market today.
    • An Open Architecture Approach to Networked Telemetry System

      Woolridge, Daniel 'Shane'; GDP Space Systems; Delta Digital Video (International Foundation for Telemetering, 2010-10)
      When designing data transport systems, Telemetry and Communications engineers always face the risk that their chosen hardware will not be available or supported soon after the hardware has been installed. The best way to reduce this risk and ensure the longevity of the system is to select an open architecture standard that is supported by multiple manufacturers. This open architecture should also have the ability to be easily upgraded and provide for all of the features and flexibility that are required to be a reliable carrier-grade edge-device. The PCI Industrial Computer Manufacturers Group (PICMG) developed the MicroTCA open standard to address the specific needs of these Communications and Network System Engineers. This paper describes the MicroTCA architecture and how it can be applied as the ideal edge-device solution for Networked Telemetry Systems applications.
    • Optical Links Capacity for LEO Satellites Over European Ground Networks

      Guérin, A.; Lacoste, F.; Laurens, A.; Azéma, G.; Périard, C.; Grimal, D.; Centre National d’Etudes Spatiales (CNES); Thales, Solutions de Securité et Services; Météo-France (International Foundation for Telemetering, 2010-10)
      Free-space optical communications offer the technology breakthrough required by future Earth Exploration Satellites for their High Rate Payload Telemetry, while they required clear sky propagation conditions leading to locate receiving optical ground stations on favorable sites in terms of atmospheric propagation and to use site diversity to reach classical system availability requirements. This paper presents a methodology that can be used to optimize such a network relying on experimental meteorological satellite data. It also presents quantitative results in terms of link availability over a European ground network and the associated downlink capacity considering possible future Low Earth Orbit satellites.
    • Performance Analysis of iNET Using Forward Error Correction and OFDM

      Dean, Richard A.; Cole-Rhodes, Arlene; Boru, Sileshi; Maitra, Diptasree; Morgan State University (International Foundation for Telemetering, 2010-10)
      This paper shows the improvement in performance for OFDM modulation on aeronautical channels with the addition of convolution coding. OFDM is envisioned for use on the Integrated Network Enhanced Telemetry (INET) on aeronautical channels that experience multipath fading which causes inter-symbol interference (ISI). Forward error correction coding, such as convolution coding (cc), significantly improves the bit error rate (BER) of OFDM with multipath fading. Theoretical and simulated results show a performance increase of up to 10dB with the introduction of coding gain and the cyclic prefix (cp). Such improvements can be applied to reduce errors or increase data rates for INET.
    • Performance Comparison of Aeronautical Telemetry in S-Band and C-Band

      Temple, Kip; Selbrede, Robert; Edwards Air Force Base (International Foundation for Telemetering, 2010-10)
      This paper compares telemetry link performance of the PCM/FM waveform when simultaneously transmitting in two different frequency bands, S-Band and C-Band. A description of the aircraft and ground station is presented followed by flight test results. These results are presented in the form of received signal strength and accumulated bit errors, versus time and link availability, over the flight paths. Conclusions are drawn based upon the presented flight test results.
    • Performance Evaluation of a TDMA MAC Protocol in Airborne Telemetry Networks

      Perrins, Erik; Sterbenz, James P. G.; Tunç, Muharrem Ali; University of Kansas (International Foundation for Telemetering, 2010-10)
      Emerging airborne telemetry networks are going beyond traditional point-to-point communication. The iNET telemetry architecture uses a TDMA MAC with relay nodes that enable multi-hop communication. We analyze the performance of the iNET TDMA MAC protocol with respect to various parameters such as number of nodes, flight range, number of relays, and number of hops via mathematical modeling. We also discuss the role of cross-layer optimizations with the AeroNP, AeroRP, and AeroTP aeronautical protocols.
    • The Performance Evaluation of an OFDM-Based IP Transceiver at Eglin AFB

      Berard, Alfredo; Cook, Paul; Roach, John; Eglin Air Force Base; Teletronics Technology Corporation (International Foundation for Telemetering, 2010-10)
      The 46th Test Wing, 846th Test Support Squadron (846 TSS/TSI) at Eglin AFB is currently evaluating their airspace for the use of SOQPSK transmitters and receivers for telemetry. The Squadron will incorporate an IP-compatible OFDM transceiver from Teletronics Technology Corporation (TTC) that will provide a two-way communication channel for controlling configuration settings of the airborne SOQPSK transmitter and receiver. This provides an opportunity to evaluate the effectiveness of an airborne network instrumentation system and measure some critical parameters, with an opportunity to assess the performance and reliability of streaming telemetry and OFDM-based IP communication systems. This paper describes the experimental test setup created for this evaluation and summarizes the measurement and evaluation process.
    • QoS Performance Management in Mixed Wireless Networks

      Dean, Richard; Astatke, Yacob; Morgan State University (International Foundation for Telemetering, 2010-10)
      This paper presents a model for Quality of Service (QoS) management in a mix of fixed Ground Station (GS) and ad-hoc telemetry networks, and introduces an enhanced clustering scheme that jointly optimizes the performance of the network using multiple distance measures based on the location of the wireless nodes and the traffic level. It also demonstrates that a "power" performance measure is an effective tool for modeling and managing QoS in Mixed Networks. Simulation results show that significant QoS performance improvements can be obtained and maintained even under severe traffic conditions.
    • The Range Area Network: A New Approach for Aeronautical Telemetry

      Rice, Michael; Tinubi, Oluwasegun; Brigham Young University (International Foundation for Telemetering, 2010-10)
      The concept of a range area network dedicated to the reception of telemetry from airborne test articles is explored. The range area network consists of ground-based radios that receive telemetry packets from an airborne test article and relay those packets through the network to a data sink (e.g., the main telemetry display and processing center). The network may use either "dumb" nodes or "smart" nodes and this choice presents a trade-off involving node complexity, network bandwidth, and required RF power. Using a somewhat idealized, but nonetheless realistic example at the Edwards AFB complex and link budgets based on the emerging iNET standard, we show that a network consisting of just 6 nodes reduces the L-band airborne transmitter power to 6W and the ground-based transmitters to 3W. If the airborne transmitter is restricted to 1W at L-band, then coverage can be provided by a grid of 50 nodes.
    • Range-Video Network (RNET)

      Berard, Alfredo; Buckley, Mark; Roach, John; Eglin Air Force Base; Teletronics Technology Corporation (International Foundation for Telemetering, 2010-10)
      The deployment of network-based airborne instrumentation systems is leading to cost-efficient replacement of legacy instrumentation systems. One application of airborne data acquisition that has been developed and maintained separately from traditional avionics and orange-wire data acquisition systems is high-speed camera packages. The development of network-based instrumentation systems has led to an opportunity to unify these two previously distinct airborne data acquisition activities. This paper describes the range-video network-based instrumentation system (rNET) being implemented by the 46th Test Wing, 846th Test Support Squadron at Eglin Air Force Base, FL to replace the existing Airborne Separation Video System (ASVS).
    • Recording in the iNET Architecture: Moving to the Future of Recording

      Cranley, Nikki; Corry, Diarmuid; ACRA Control (International Foundation for Telemetering, 2010-10)
      At the heart of many networked Flight Test Instrumentation (FTI) systems is the Network- Recorder. The high data rates typical in networked FTI systems put increased demands on the Network-Recorder to support ever faster read and write rates. However, thanks to the developments in CompactFlash and SATA technologies, such recording rates are achievable in the Network-Recorder. This paper discusses several ways in which the recorder can be optimized to improve the memory capacity usage, writing speed and relevance of the recorded data.
    • Reduced Complexity Viterbi Decoders for SOQPSK Signals over Multipath Channels

      Saquib, Mohammad; Kannappa, Sandeep Mavuduru; University of Texas at Dallas (International Foundation for Telemetering, 2010-10)
      High data rate communication between airborne vehicles and ground stations over the bandwidth constrained Aeronautical Telemetry channel is attributed to the development of bandwidth efficient Advanced Range Telemetry (ARTM) waveforms. This communication takes place over a multipath channel consisting of two components - a line of sight and one or more ground reflected paths which result in frequency selective fading. We concentrate on the ARTM SOQPSKTG transmit waveform suite and decode information bits using the reduced complexity Viterbi algorithm. Two different methodologies are proposed to implement reduced complexity Viterbi decoders in multipath channels. The first method jointly equalizes the channel and decodes the information bits using the reduced complexity Viterbi algorithm while the second method utilizes the minimum mean square error equalizer prior to applying the Viterbi decoder. An extensive numerical study is performed in comparing the performance of the above methodologies. We also demonstrate the performance gain offered by our reduced complexity Viterbi decoders over the existing linear receiver. In the numerical study, both perfect and estimated channel state information are considered.
    • A Reflection Type Phase Shifter for iNET Phase Array Antenna Applications

      Shrestha, Bikram; Morgan State University (International Foundation for Telemetering, 2010-10)
      In this article we present results from modeling and simulation of a L-band reflection type phase shifter (RTPS) that provides continuous phase shift of 0° to 360°. The RTPS circuit uses a 90º hybrid coupler and two reflective load networks consisting of varactor diodes and inductors. Proper design of 90° hybrid coupler is critical in realizing maximum phase shift. The RTPS circuit implemented on a Rogers Duroid substrate is large in size. We discuss methods to reduce the size of L-band RTPS.
    • Refraction Effects for Tracking Error at C- & S-Band Frequencies

      Oh, Chang Yul; Lee, Hyo Keun; Oh, Seung Hyeub; Korea Aerospace Research Institute; Chungnam National University (International Foundation for Telemetering, 2010-10)
      This document is focused on the examination of the tracking angular error due to the radio refraction for the target in low altitude of less than 5km and in low elevation angle. The real measured data using the GPS and the tracking systems of C- and S-band frequency in NARO Space centre, Korea are used for the analysis. The analysis shows couple of conclusions on the radio refraction effects; there are angular errors due to the radio refraction which is not to be neglected comparing the accuracy of the tracking system but to be considered for the precise measurement of the target position. Also, the refraction errors are dependent on the target altitude, but not on the frequency.
    • Remote Imaging System Acquisition (RISA) Space Environment Multispectral Imager

      Grubbs, Elmer; Marcellin, Michael; Lizarrage, Adrian; Lynn, Brittany; Lange, Jeremiah; University of Arizona (International Foundation for Telemetering, 2010-10)
      The purpose of the NASA Remote Imaging System Acquisition space camera prototype is to integrate multiple optical instruments into a small wireless system using radiation tolerant components. This stage of prototyping was the development of a broadband variable-focus camera that can transmit data wirelessly. A liquid lens in conjunction with a cerium doped double gauss eliminates traditional focusing mechanisms.