• Channel Equalization and Spatial Diversity for Aeronautical Telemetry Applications

      Saquib, M.; Williams, Ian E.; University of Texas at Dallas (International Foundation for Telemetering, 2010-10)
      This work explores aeronautical telemetry communication performance with the SOQPSK- TG ARTM waveforms when frequency-selective multipath corrupts received information symbols. A multi-antenna equalization scheme is presented where each antenna's unique multipath channel is equalized using a pilot-aided optimal linear minimum mean-square error filter. Following independent channel equalization, a maximal ratio combining technique is used to generate a single receiver output for detection. This multi-antenna equalization process is shown to improve detection performance over maximal ratio combining alone.
    • Compressed Sensing Using Reed-Solomon and Q-Ary LDPC Codes

      Ryan, William E.; Marcellin, Michael W.; Goodman, Nathan A.; Jagiello, Kristin M.; University of Arizona (International Foundation for Telemetering, 2010-10)
      We consider the use of Reed-Solomon (RS) and q-ary LDPC codes for compressed sensing of sparse signals. Signals sensed using the RS parity-check matrix are recovered using Berlekamp-Massey and those sensed using the LDPC parity-check matrix are recovered using majority-logic decoding. Results are presented for both types of sensing. In addition, a hardware architecture is discussed.
    • Data Embedding in Video Telemetry Systems

      Dolan, P.; MIT Lincoln Laboratory (International Foundation for Telemetering, 2010-10)
      This paper presents a technique for embedding a digital data stream within a digital video stream using wavelet and nonlinear subband decompositions. This technique may enable more efficient use of radio frequency (RF) spectrum and a reduction in hardware necessary to transmit one or more narrowband data streams on a payload that incorporates a digital video camera. Several data embedding examples are presented which show how relatively large payloads can be embedded in even a single image with little noticeable degradation in image quality.
    • Decoding and Turbo Equalization for LDPC Codes Based on Nonlinear Programming

      Iltis, Ronald A.; University of California, Santa Barbara (International Foundation for Telemetering, 2010-10)
      Decoding and Turbo Equalization (TEQ) algorithms based on the Sum-Product Algorithm (SPA) are well established for LDPC codes. However there is increasing interest in linear and nonlinear programming (NLP)-based decoders which may offer computational and performance advantages over the SPA. We present NLP decoders and Turbo equalizers based on an Augmented Lagrangian formulation of the decoding problem. The decoders update estimates of both the Lagrange multipliers and transmitted codeword while solving an approximate quadratic programming problem. Simulation results show that the NLP decoder performance is intermediate between the SPA and bit-flipping algorithms. The NLP may thus be attractive in some applications as it eliminates the tanh/atanh computations in the SPA.
    • Describing Telemetry Systems with the Metadata Description Language

      Moore, Michael S.; Price, Jeremy C.; Cormier, Andrew R.; Thibodeaux, Ryan J.; Abbott, Ben A.; Malatesta, William A.; Southwest Research Institute; Naval Air Systems Command (NAVAIR) (International Foundation for Telemetering, 2010-10)
      The integrated Network-Enhanced Telemetry (iNET) project has developed standards to enhance telemetry systems for the twenty-first century. A foundational component of these standards is the Metadata Description Language (MDL). MDL is an eXtensible Markup Language (XML)-based language for describing requirements, design choices, and configuration parameters of a Telemetry Network System (TmNS). Within a TmNS, MDL guides the exchange of information between applications and the configuration of network devices. Recent initial evaluations assessed MDL in terms of the expressive power of the language and the level of effort in developing applications that utilize MDL Instance Documents. Performing these initial evaluations required the generation of MDL Instance Documents to describe scenarios representative of both near-term and future telemetry systems that express different levels of iNET interoperability. These initial evaluations determined quantitative metrics such as file size, memory requirements, and required parsing time for MDL Instance Documents, and further evaluations judged the efficacy and complexity of MDL for describing and configuring a TmNS.
    • Design and Analysis of a 3-D Gauss-Markov Model for Highly Dynamic Airborne Networks

      Sterbenz, James P. G.; Broyles, Dan; Jabbar, Abdul; University of Kansas (International Foundation for Telemetering, 2010-10)
      Accurate mobility models are needed to simulate the physical movement of nodes in a highly-dynamic aeronautical network. The fundamental problem with many synthetic mobility models is their random, memoryless behavior. Airborne ad hoc networks require a flexible memory-based 3-dimensional mobility model. We present a new 3-dimensional implementation of the Gauss-Markov mobility model for airborne telemetry network simulations, and compare its behavior to memoryless models such as random waypoint and random walk using the ns-3 simulator.
    • The Design of an Application Used for Aircraft Stability Evaluation

      Leite, Nelson Paiva Oliveira; Lopes, Leonardo Mauricio de Faria; Walter, Fernando; Grupo Especial de Ensaios em Vôo; Instituto Tecnológico de Aeronáutica (International Foundation for Telemetering, 2010-10)
      One of the most important characteristics of an aircraft is its capability to return to its stable trimmed flight state after the occurrence of a disturbance or gust without the pilot intervention. The evaluation of such behavior, known as the aircraft stability, is divided into three sections: Lateral; Directional; and Longitudinal stabilities. The determination of the stability of an experimental aircraft requires the execution of a Flight Test Campaign (FTC). For the stability FTC the test bed should be equipped with a complete Flight Test Instrumentation (FTI) System which is typically composed by: a Pulse Code Modulation (PCM) Data Acquisition System (DAS); A sensor set; An airborne transmitter; and A data recorder. In the real-time operations, live data received over the Telemetry Link, that are processed, distributed and displayed at the Ground Telemetry System (GTS) enhances the FTC safety level and efficiency. The due to the lack of reliability, recorded data is retrieved in the post mission operations to allow the execution of data reduction analysis. This process is time consuming because recorded data has to be downloaded, converted to Engineering Units (EU), sliced, filtered and processed. The reason for the usage of this less efficient process relies in the fact that the real-time Telemetry data is less reliable as compared to recorded data (i.e. noisier). The upcoming iNET technology could provide a very reliable Telemetry Link. Therefore the data reduction analysis can be executed with live telemetry data in quasi-real time after the receipt of all valid tests points. In this sense the Brazilian Flight Test Group (GEEV) along with EMBRAER and with the support of Financiadora de Estudos e Projetos (FINEP) started the development of several applications. This paper presents the design of a tool used in the Longitudinal Static Stability Flight Tests Campaign. The application receives the Telemetry data over either a TCP/IP or a SCRAMnet Network, performs data analysis and test point validation in real time and when all points are gathered it performs the data reduction analysis and automatically creates Hyper Terminal Markup Language (HTML) formatted tests reports. The tool evaluation was executed with the instruction flights for the 2009 Brazilian Flight Test School (CEV). The result shows an efficiency gain for the overall FTC.
    • Development and Analysis Cloud

      Self, Lance; Kirtland Air Force Base (International Foundation for Telemetering, 2010-10)
      The development and analysis cloud is a rapid development system being designed to support the Air Force Research Lab (AFRL) Simulation & Technology Assessment Branch. The purpose is to isolate research, development, test, and evaluation of unique software within a Zone D enclave [1] to allow researchers and analysts to develop and test software free of the many IT requirements that hamper development and without risk of contaminating the overall Air Force network. The cloud system is being designed so researchers and analysts will utilize Software as a Service (SaaS) models. Such a model makes it transparent to users such things as where the software originates and any licensing concerns. Utilities, tools, and other enhancing software that users need are published and using them frees the developer to focus on their specific development efforts versus tertiary development modules.
    • Digital Cross-Polar Interference Canceller

      Thesling, Bill; ViaSat, Inc. (International Foundation for Telemetering, 2010-10)
      Dual-polarized data transmission promises to double the system capacity by transmitting independent signals simultaneously on both polarizations in the same channel. However, the polarization orthogonality of the propagation field can not always be perfectly preserved in various environments. Also the antenna and waveguide networks may not be able to achieve absolute polarization isolation. Therefore cross-polarization interference becomes a severe source of performance degradation in dual-polar systems. This paper presents an all-digital design of the cross-polarization interference canceller (XPIC or CPIC). This canceller is designed to remove the cross-polar interference so that comparable performance to single-polar system can be achieved for each polarization. Specifically, this digital design aims for • Mitigating the cross-polarization interference caused primarily by antenna orientation. (Delay between the signals from both polarizations is considered insignificant.) • Can operate with time varying cross-polar interference varying at rates of 2-3 Hz and beyond. • Initial isolation can be as low as 10 dB. • Is well suited to an all digital modem where clocking from the A/D is independent of symbol timing recovery clocks.
    • Direct Spatial Antenna Modulation for Wideband Phase Control

      Uhl, Brecken; Invertix Corporation (International Foundation for Telemetering, 2010-10)
      Direct spatial antenna modulation (DSAM) is a new approach to phased array control that opens up new "smart antenna" architecture possibilities. The DSAM technique leverages the inherent spatial differences of excitation in an antenna in a novel way to achieve the equivalent of conventional modulation and beam control effects. Smart antenna techniques are of potentially increasing importance to test range operations given a trend toward more flexible, internetworked, and autonomous test activities. The DSAM technique has been demonstrated through several generations of analysis, simulation, and prototyping, but has previously only been applied to narrowband antenna designs. Furthermore, the IQ DSAM approach in particular has not been previously implemented in hardware. This paper details the application of IQ DSAM to achieve wideband phase control using a commercial off the shelf (COTS) antenna. The phase control performance of IQ DSAM over a range of 1.5 GHz to 4 GHz is measured across relative field control angles of +/- 45 degrees. The measured IQ DSAM performance is compared to what could be expected from a conventional phased array element control architecture.
    • Dynamic Formatting of the Test Article Data Stream

      Young, Tom; Wigent, Mark; AFFTC; SAIC (International Foundation for Telemetering, 2010-10)
    • Dynamic Frequency Assignment and Management Technologies for Future Test and Evaluation Operations

      Painter, Michael K.; Fernandes, Ronald; Gohlke, Jason; Ramachandran, Satheesh; Verma, Ajay; Jones, Charles H.; Knowledge Based Systems, Inc.; Edwards Air Force Base (International Foundation for Telemetering, 2010-10)
      There is growing concern that the U.S. military can no longer meet its domestic and international spectrum needs. Demand for this resource is growing at an exponential pace, both within the Department of Defense (DoD) and in the commercial sector (partly due to rapid growth in broadband wireless electronics). A microcosm of these challenges is evident in flight test operations, where there is a growing need for advanced spectrum assignment, frequency deconfliction, and scheduling optimization decision support capabilities. This paper describes research aimed at investigating how to optimize frequency scheduling, dynamic assignment, and real-time metrics adjustment to promote assured access to the electronic spectrum, including emerging technology developments to support that need.
    • End-to-End ARQ: Transport-Layer Reliability for Airborne Telemetry Networks

      Sterbenz, James P. G.; Pathapati, Kamakshi Sirisha; Rohrer, Justin P.; University of Kansas (International Foundation for Telemetering, 2010-10)
      Due to the mission-critical nature of command-and-control traffic in the telemetry environment, it is imperative that reliable transfer be supported. The AeroTP disruption-tolerant transport protocol is intended for this environment. The mechanism for reliable transfer is ARQ with end-to-end acknowledgments. This has significant performance limitations resulting from the highly-dynamic nature of airborne telemetry networks, since end-to-end paths may not persist long enough for retransmissions to be received. We use ns-3 to analyze the AeroTP ARQ mechanism, along with tunable parameters that may improve performance in reliable transfer mode.
    • An Enhancement of Existing RF Data Links Using Advanced Diversity Techniques

      Melicher, Milos; ACRA Control (International Foundation for Telemetering, 2010-10)
      The theoretical capacity of communication channel in the presence of additive white Gaussian noise (AWGN) as defined by Shannon's channel capacity theorem has been well understood since 1940s. This theorem bounds the bit error rate (BER) of RF data links achievable for a particular noise level. The development in digital technology over the last decade has made it possible not just to design devices that operate close to the Shannon's limit, but also to explore techniques, such as best source and best data selectors, for further improvements in performance of RF data links where frequency, spatial or polar diverse reception is possible. This paper discusses an approach to improving quality of data links using an advanced diversity technique that does not select one source at a time but aligns and combines soft values from each. It shows how the overall bit error rate of RF data link can be improved by combining signals from multiple receivers and/or transmitters. Test results showing practical performance improvements are presented and discussed.
    • FTI Network Discover, Health, and Status Monitoring

      Cranley, Nikki; ACRA Control (International Foundation for Telemetering, 2010-10)
    • Hardware-Efficient Implementation of the SOVA for SOQPSK-TG

      Perrins, Erik; Hosseini, Ehsan; Rea, Gino; University of Kansas (International Foundation for Telemetering, 2010-10)
      In this paper, we present a hardware-efficient architecture of a demodulator for shaped offset quadrature phase shift keying, telemetry group version (SOQPSK-TG). The demodulation is done using the soft-output Viterbi algorithm (SOVA), which is implemented by the two-step traceback method. In this method, two traceback operations are employed to find the maximum-likelihood (ML) path and the competing path. Using the proposed architecture, the tracebacks are done at the same time as the demodulator is generating output bits and their reliabilities. This method has been shown to require less storage than the well-known register-exchange method. Finally, we present the performance results from the FPGA implementation.
    • Helicopter Slip Ring Replacement System

      Adamson, Alan; Berdugo, Albert; Flight Test Instrumentation; Teletronics Technology Corporation (International Foundation for Telemetering, 2010-10)
      Most helicopter programs require the acquisition of parameters from the rotating systems. Historically, these systems made use of electromechanical slip rings for the transfer of power, control, and data from within the helicopter's cabin to the rotating hardware. Slip rings are primarily used in dedicated instrumentation vehicles and are not commonly used in production platforms that may require instrumentation of the rotating systems for in-service load and fatigue monitoring. Additionally, the use of slip rings requires time and money to integrate the hardware and equipment into the aircraft in order to perform rotor data acquisition. The time needed to perform modifications to transmissions and drive trains plays a big factor in the increased costs of aircraft development. Less intrusive installations would minimize the need for mechanical changes and would improve the time needed to install the instrumentation. This paper describes a wireless system approach to perform the test without the slip ring, and provides performance data that validates this new method of instrumenting unobtrusively to save time and money without sacrificing data integrity.
    • High Data Rate ARTM Tier II Telemetry Waveforms Receiver Analysis and Design

      Dourbal, Paul; Bouglo, Yuriy; Fleyshman, Val; Mayer, Robert; Okoro, Jerry; Shikhalev, Boris; L-3 Telemetry East (International Foundation for Telemetering, 2010-10)
      In this article we show how phase noise and demodulator complexity define the potential performance of high data rate telemetry receivers for ARTM continuous phase modulation (ARTM CPM) signals. Given a level of phase noise and demodulator complexity, we can predict the potential performance of a receiver. We also provide the results of actual receiver performance measurements (obtained using RCB-4000 Telemetry Receiver). We develop a simplified analytical model for an ARTM CPM signal transmission and present the resulting equation for phase increment difference between close signal sequences. The analysis of demodulator performance deterioration due to inter-symbol interference and due to receiver phase noise is then provided. Actual receiver phase noise data is included and is used to analyze demodulator performance.
    • How to Use Analog Telemetry to Produce Equipment with 100% Reliability

      Losik, Len; Failure Analysis (International Foundation for Telemetering, 2010-10)
      Equipment reliability is driven by infant mortality failures, which can be eliminated using a prognostic analysis prior, during and/or after the exhaustive and comprehensive dynamic environmental factory acceptance testing which conducted to increase equipment reliability by identifying equipment that fails during test for repair/replacement. To move to the 100% reliability domain, equipment dynamic environmental factory testing should be followed by a prognostic analysis to identify the equipment that will fail within the first year of use. During all equipment testing, only equipment functional performance is measured and equipment performance is unrelated to short-term or long-term equipment reliability making testing alone inadequate to produce equipment with 100% reliability. A prognostic analysis converts performance measurements to reliability measurements invasively by sharing test data used to measure equipment performance. Performance data that is converted to reliability data provides a time-to-failure (TTF) in minutes/hours/days/months for equipment that will fail within the first year of use, allowing the production of equipment with 100% reliability, decreasing risk and making getting to space safe and reliable.
    • A Hybrid Data Acquisition Architecture on the CH-53K Program

      Dehmelt, Chris; L3 Communications Telemetry East (International Foundation for Telemetering, 2010-10)
      As today's flight test programs need for sensor and bus data continue to increase, there has been associated requirements to provide modern system output products and support higher encoder data rates. The CH-53K Heavy Lift Replacement (HLR) Program is an example in which the instrumentation data requirements have increased significantly over previous helicopter programs and necessitated the introduction of new technologies and capabilities. The CH-53K Program utilizes a hybrid system architecture that combines the benefits of legacy PCM and modern networked system architectures. The system provides for maintaining the required system-wide synchronized sampling capabilities, while providing real-time data access and system control over a vehicle network. Serial Streaming Telemetry (SST)-to-vNET Adapters are employed to enable many of these capabilities. This paper describes the instrumentation requirements for the CH-53K program and the features, tools and performance of its data acquisition system - which addressed all requirements while minimizing the overall impact to the existing instrumentation infrastructure.