• Measuring and Evaluating Best Source Selection

      Corry, Diarmuid; ACRA Control Inc. (International Foundation for Telemetering, 2009-10)
      To properly evaluate and characterize the performance of a bit synchronizer we need to apply a known data stream and then adjust several interference parameters to measure the effect on synchronization performance: white noise, offset and gain variations and frequency and phase shifts. The task becomes more complex when we consider the performance of a best source selector (BSS) which combines the performance of two or more bit synchronizers to achieve better bit error rates and more consistent synchronization than can be achieved with one alone. Each of the parameters (noise, offset, gain, phase) are often different for each bit synchronizer, and may vary over time. In addition the incoming bit streams can drift in time (possibly 100s of bits) with respect to each other. This paper discusses how these parameters are measured, and looks in particular at the problem of evaluating a BSS. Results showing the performance that can be achieved when aligning and combining multiple streams are presented and discussed.
    • Metadata Description Language: The iNET Metadata Standard Language

      Moore, Michael S.; Price, Jeremy C.; Cormier, Andrew R.; Malatesta, William A.; Southwest Research Institute; Naval Air Systems Command (NAVAIR) (International Foundation for Telemetering, 2009-10)
      In order to help manage the complexity in designing and configuring network-based telemetry systems, and to promote interoperability between equipment from multiple vendors, the integrated Network-Enhanced Telemetry (iNET) Metadata Standards Working Group (MDSWG) has developed a standard language for describing and configuring these systems. This paper will provide the community with an overview of Metadata Description Language (MDL), and describe how MDL can support the description of the requirements, design choices, and the configuration of devices that make up the Telemetry Network System (TmNS). MDL, an eXtensible Markup Language (XML) based language that describes a TmNS from various aspects, is embodied by an XML schema along with additional rules and constraints. Example MDL instance documents will be presented to illustrate how MDL can be used to capture requirements, describe the design, and configure the equipment that makes up a TmNS. Various scenarios for how MDL can be used will be discussed.
    • A Method for Tracking the Accuracy of Channel Estimates in MIMO Receivers

      Kosbar, Kurt; Gupte, Abhishek; Missouri University of Science and Technology (International Foundation for Telemetering, 2009-10)
      Multiple input multiple output communication systems offer significant advantages, but only if the receiver has an accurate estimate of the channel state information (CSI). To obtain a CSI estimate, the transmitter must stop sending data, and instead send a training sequence. To maximize throughput, the time spent sending training data should be minimized. This paper describes a method which allows the receiver to track the accuracy of its CSI estimate, so that it can request new training data only when necessary.
    • A Model-Based Methodology for Managing T&E Metadata

      Hamilton, John; Fernandes, Ronald; Darr, Timothy; Graul, Michael; Jones, Charles; Weisenseel, Annette; Knowledge Based Systems, Inc.; Edwards Air Force Base (International Foundation for Telemetering, 2009-10)
      In this paper, we present a methodology for managing diverse sources of T&E metadata. Central to this methodology is the development of a T&E Metadata Reference Model, which serves as the standard model for T&E metadata types, their proper names, and their relationships to each other. We describe how this reference model can be mapped to a range's own T&E data and process models to provide a standardized view into each organization's custom metadata sources and procedures. Finally, we present an architecture that uses these models and mappings to support cross-system metadata management tasks and makes these capabilities accessible across the network through a single portal interface.
    • Multipath Mitigation for Aeronautical Telemetry with Multiple Antennas

      Saquib, M.; Williams, Ian E.; University of Texas at Dallas (International Foundation for Telemetering, 2009-10)
      Frequency selective multipath is a key performance limiter for aeronautical telemetry applications. Our research explores multipath mitigation techniques with ARTM Tier-1 waveforms using linear adaptive filters, multiple receive antennas and error-based best source selection. Single antenna adaptive equalization alone is unable to substantially improve performance under certain channel conditions. Analytical investigations demonstrate that nonlinear channel phase response is the principal cause of performance loss. In this adverse environment, spatial diversity with multiple receive antennas along with error-based best source selection are capable of improving bit error rate performance by 5dB for each additional antenna.
    • Network Telemetry Link Throughput Maximization Approaches

      Moodie, Myron L.; Newton, Todd A.; Abbott, Ben A.; Southwest Research Institute (International Foundation for Telemetering, 2009-10)
      The use of Ethernet and Internet Protocol (IP) networking technologies in flight test instrumentation and telemetry systems is rapidly increasing, driven by the ubiquity, scalability, and flexibility of networking technologies. Networks first made a positive impact in ground station infrastructure and have recently been emerging in test article data acquisition infrastructure in programs such as the A380, 787, P-8A, and Future Combat Systems. The next logical step is to provide a two-way network telemetry link to fully extend the flexibility of the network between the test articles and ground station. The United States Department of Defense (DoD) integrated Network-Enhanced Telemetry (iNET) program is currently working to build a standardized network telemetry link for exactly this purpose. When developing a network telemetry link, the limited availability of telemetry spectrum must be considered and thus it is critical to choose system-level approaches to maximize the throughput achieved from the link. This paper first presents the statistics of the network data that would typically use this link based on empirical data from current network-based flight test instrumentation systems. Several approaches to using a network telemetry link are then presented. Predicted achievable throughputs of each approach are presented that are derived from the statistics of the empirical test data. Based on this, the paper presents recommendations for building systems using network telemetry links.
    • Networked Flight Test Instrumentation Data Recording Solutions

      Cranley, Nikki; Corry, Diarmuid; ACRA Control, Inc. (International Foundation for Telemetering, 2009-10)
      An integral component of networked Flight Test Instrumentation (FTI) and Health and Usage Monitoring Systems (HUMS) is the networked Data Recorder. The high data rates achievable in networked data acquisition systems put increased demands on the recorder to support ever faster read and write rates. Key to the success of the networked recorder is the format in which the data is recorded. The data recording file format should be network-centric with a low processing overhead to support the recording demands. In this paper the popular file formats, Chapter 10 and the Packet CAPture (PCAP), that are used for recording networked FTI are analyzed and compared.
    • Obtaining an ATO for an iNET Operational Demonstration

      Hodack, David; Naval Air Systems Command (International Foundation for Telemetering, 2009-10)
      The integrated Network Enhanced Telemetry (iNET) project was launched to foster network enhanced instrumentation and telemetry. The program is currently implementing an operational demonstration. That will involve installing and using a network enhanced instrumentation system on a helicopter. This demonstration will be used as a learning exercise for the implementation of network technologies. This paper will give a brief description of the operational demonstration. Then it will explore the need for an Authority to Operate (ATO) and describe how one was obtained.
    • OFDM Performance on Aeronautical Channnels

      Dean, Richard; Kamirah, Daniel K.; Morgan State University (International Foundation for Telemetering, 2009-10)
      This paper provides an introduction to the Orthogonal Frequency Division Multiplexing (OFDM) scheme which has been proposed for future aeronautical telemetry applications. OFDM offers the potential for high data rates on radio channels with multipath such as aeronautical telemetry channels. This paper provides in introduction to OFDM and demonstrates how orthogonality is maintained over multipath channels by the introduction of a guard band and by the inclusion of a cyclic prefix. The simulation of OFDM in multipath is simulated and performance results are presented that show the degradation of this scheme on a multipath channel with and without the guard band and the cyclic prefix.
    • Pacific Ranges Interoperable Test & Evaluation Capabilities (PRITEC)

      Hermann, Scott A.; Wigent, Mark A.; Chavez, Tomas C.; PMRF; SAIC; CSC (International Foundation for Telemetering, 2009-10)
      The office of the Defense Test Resources Management Center (DTRMC) has developed two major programs to achieve Joint/Interoperable exercises between DoD test and training ranges. Joint Mission Environment Test Capability (JMETC) defines a LVC environment in which Joint operations take place, while the Test and Training Enabling Architecture (TENA) defines the communication within that environment. Putting these programs to everyday use has been a challenge for the ranges. The Pacific Missile Range Facility (PMRF) is executing the Central Test & Evaluation Investment Program (CTEIP) sponsored Pacific Ranges Interoperable Test & Evaluation Capabilities (PRITEC) project designed to develop a set of tools that will facilitate implementation of JMETC and TENA. This paper will discuss the PRITEC project in detail.
    • Performance Analysis of Reentry TDOA Positioning System

      Nan, Xie; Futang, Zhang; China Academy of Engineering Physics (International Foundation for Telemetering, 2009-10)
      In reentry measurement, we need to measure the track of reentry vehicle. For the speed of target is very high, it is difficult for traditional positioning system to capture and track the target. TDOA (time difference of arrival) positioning system is used in reentry measurement. The position of target is calculated by using time difference of arrival. This paper introduces the principle of reentry TDOA positioning system. The key technology is synchronization of ground stations' clocks. The implementation of clock synchronization using low-cost commercial GPS receiver is presented. The sources of errors in the existing telemetry system, corresponding precision and experimental results are presented. Some methods, which are used to improve the precision, are proposed at the end of this paper.
    • Performance and Disruption Tolerance of Transport Protocols for Airborne Telemetry Networks

      Sterbenz, James P. G.; Rohrer, Justin P.; University of Kansas (International Foundation for Telemetering, 2009-10)
      The airborne telemetry environment presents unique challenges to end-to-end communications due to the highly dynamic topology and time-varying connectivity of high-velocity wireless nodes. The AeroTP transport protocol uses multiple reliability modes to trade off end-to-end reliability and efficiency as appropriate for different categories of telemetry data. Based on the architecture previously presented, we have further developed the design of this protocol, as well as performing preliminary simulations of AeroTP using the ns-3 simulation platform. In this paper we present the operational modes of AeroTP in greater detail, as well as comparing the performance of TCP with the AeroTP domain-specific transport protocol.
    • Performance Comparison of OFDM and DSSS on Aeronautical Channels

      Cole-Rhodes, Arlene; Dean, Richard; Ehichioya, Daniel; Golriz, Arya; Morgan State University (International Foundation for Telemetering, 2009-10)
      This paper develops a performance framework for OFDM by contrasting its performance with Direct Sequence Spread Spectrum (DSSS) over aeronautical channels. Each of the OFDM and DSSS modulated simulations are put through the channel and compared on terms of signal to noise ratio (SNR) versus bit error rate. The simulation will show that DSSS will have better power efficiency on multipath channels because the rake receiver adds all multipath components to strengthen the receiver. By contrast OFDM with an equalizer will have better spectrum efficiency results where QAM modulation of multiple tones allows for high data rates in a limited bandwidth. This work develops a framework for contrasting the performance of the rake receiver and the equalizer for operation on multipath channels. By comparing these schemes on various channels the choice of OFDM for iNET can be clearly understood and evaluated.
    • The Performance Evaluation of an OFDM-Based iNET Transceiver

      Lu, Cheng; Roach, John; Teletronics Technology Corporation (International Foundation for Telemetering, 2009-10)
      The nXCVR-2000G transceiver is an 802.11a OFDM-based system undergoing performance studies that uses both simulation and laboratory tests. The multi-path channel model used in the simulation experiments is based on a telemetry multi-path channel model described in the iNET Telemetry Experimental Standard document. To date, the results using the simulation have been confirmed by outdoor laboratory tests. They show that multi-path has less impact on the OFDM performance when the channel spread is within a limit of 800ns; the same specified guard interval (GI) used by 802.11a. For example, with a channel spread of 144ns (τ1) and a reflection coefficient of -0.26dB (Γ1), the Error Vector Magnitude (EVM) is on the order of 2.5%. As the channel spread expands beyond the standard GI 800ns, the demodulated signal degrades. The performance penalty depends upon the channel spread factor and the total Signal to Interference plus Noise Ratio (SINR).
    • Performance of an OFDM-Based DVB-T System and its FPGA Implementation

      Yang, Luyu; Song, Peng; Song, Qingping; North China University of Technology (International Foundation for Telemetering, 2009-10)
      Orthogonal frequency division multiplexing (OFDM) is a new technique for data transmission. Conforming to the final draft of OFDM-based DVB-T (ETSI EN 300 744 V1.6.1), which is intended for digital terrestrial television broadcasting, a DVB-T baseband system is designed. The system performance is simulated in MATLAB using Simulink. Then it is implemented on Field Programmable Gate Array (FPGA) with the help of System Generator software. The result shows that OFDM is robust against multipath effect and convenient for implementation as well, thus owning a quite promising future.
    • Post Processing Data Analysis

      Irick, Nancy; Raytheon Missile Systems (International Foundation for Telemetering, 2009-10)
      Once the test is complete, the job of the Data Analyst has begun. Files from the various acquisition systems are collected. It is the job of the analyst to put together these files in a readable format so the success or failure of the test can be attained. This paper will discuss the process of breaking down these files, comparing data from different systems, and methods of presenting the data.
    • Potential Solutions to Communications During Plasmasonic Flight

      Jones, Charles H.; Air Force Flight Test Center (International Foundation for Telemetering, 2009-10)
      At about Mach number 10 and above, a high energy plasma field forms around a vehicle. This plasma sheath has a high attenuation factor that can cause communications black out. No practical solutions to communicating through a plasma sheath are known. In addition to standard real time data needs for test, a driving requirement to solve this problem is that most solutions will have to be designed into the vehicle. Modifications of vehicles designed to travel at these Mach numbers, especially any exterior modifications, will be extremely difficult due to effects on aerodynamics, thermal protection, and the materials used. A list of possible solutions to communications through hypersonically induced plasma has been collected over several years. This list was added to and verified during the Workshop on Communications through Plasma during Hypersonic Flight. Pros and cons of these potential solutions have been discussed and documented as well. The workshop also included a vote by the attending experts on what solutions are most promising. This paper reviews these solutions, their pros and cons, and a recommended way forward to solving this problem.
    • Preamble Design for Symbol Timing Estimation from SOQPSK-TG Waveforms

      Erkmen, Baris I.; Tkacenko, Andre; Okino, Clayton M.; California Institute of Technology (International Foundation for Telemetering, 2009-10)
      Data-aided symbol synchronization for bursty communications utilizes a predetermined modulation sequence, i.e., a preamble, preceding the payload. For effective symbol synchronization, this preamble must be designed in accordance with the modulation format. In this paper, we analyze preambles for shaped offset quadrature phase-shift keying (SOQPSK) waveforms. We compare the performance of several preambles by deriving the Cram´er-Rao bound (CRB), and identify a desirable one for the Telemetry Group variant of SOQPSK. We also demonstrate, via simulation, that the maximum likelihood estimator with this preamble approaches the CRB at moderate signal-to-noise ratio.
    • A Programmable Dual Modulator Testbed for MIMO Applications

      Kosbar, Kurt; Seaber, John; Barkley, Jacob; Ngo, Tony; Poettgen, Adam; Missouri University of Science and Technology (International Foundation for Telemetering, 2009-10)
      Multiple-input multiple-output (MIMO) systems use multiple transmitters and receivers to increase the capacity and reliability of radio frequency communication links used in multipath and disruptive environments. This paper describes a recently designed hardware testbed that can be used as a modulator and transmitter for MIMO systems which use two transmitters. The testbed consists of a field programmable gate array (FPGA) that generates the I/Q baseband signals for the two transmitters. A wide variety of modulation and coding formats, up to data rates of 10 Mbps, can be implemented by reprogramming the FPGA. The dual I/Q outputs from the FPGA are then fed to a pair of quadrature modulators, which have programmable carrier frequencies from 1,025 to 2,450 MHz. The system is implemented on a single printed circuit board, and has dual RF outputs with programmable power levels up to 0 dBm.
    • Proposed iNET Network Security Architecture

      Dean, Richard; Dukes, Renata; Morgan State University (International Foundation for Telemetering, 2009-10)
      Morgan State University's iNET effort is aimed at improving existing telemetry networks by developing more efficient operation and cost effectiveness. This paper develops an enhanced security architecture for the iNET environment in order to protect the network from both inside and outside adversaries. This proposed architecture addresses the key security components of confidentiality, integrity and authentication. The security design for iNET is complicated by the unique features of the telemetry application. The addition of encryption is complicated by the need for robust synchronization needed for real time operation in a high error environment.