• A 3-CHANNEL MONOPULSE TRACKING RECEIVER SYSTEM USING COMMERCIAL OFF-THE-SHELF EQUIPMENT

      Champion, James; Microdyne Communications Technologies, Inc. (International Foundation for Telemetering, 1998-10)
      Three-channel monopulse tracking receiver systems are commonly used for high performance tracking of satellites, missiles, or aircraft to maximize the reception of data. Typically, the receiver in such systems are custom designed for their end purpose. This results in a high cost to cover the development, service, and support of a highly specialized piece of equipment. This paper covers the requirements and performance of a 3-channel monopulse tracking receiver assembled from commercial-off-the-shelf (COTS) equipment. Such a system provides an option for designing or upgrading tracking stations with the lower cost, larger support base, and greater system configuration choices that are available with COTS equipment.
    • 625 MBIT/SEC BIT ERROR LOCATION ANALYSIS FOR INSTRUMENTATION RECORDING APPLICATIONS

      Waschura, Thomas E.; SyntheSys Research Incorporated (International Foundation for Telemetering, 1998-10)
      This paper describes techniques for error location analysis used in the design and testing of high-speed instrumentation data recording and communications applications. It focuses on the differences between common bit error rate testing and new error location analysis. Examples of techniques presented include separating bit and burst error components, studying probability of burst occurrences, looking at error free interval occurrence rates as well as auto-correlating error position. Each technique contributes to a better understanding of the underlying error phenomenon and enables higher-quality digital recording and communication. Specific applications in error correction coding emulation, magnetic media error mapping and systematic error interference are discussed.
    • Accuracy of Computer Simulations that use Common Pseudo-random Number Generators

      Dusitsin, Krid; Kosbar, Kurt; University of Missouri – Rolla (International Foundation for Telemetering, 1998-10)
      In computer simulations of communication systems, linear congruential generators and shift registers are typically used to model noise and data sources. These generators are often assumed to be close to ideal (i.e. delta correlated), and an insignificant source of error in the simulation results. The samples generated by these algorithms have non-ideal autocorrelation functions, which may cause a non-uniform distribution in the data or noise signals. This error may cause the simulation bit-error-rate (BER) to be artificially high or low. In this paper, the problem is described through the use of confidence intervals. Tests are performed on several pseudo-random generators to access which ones are acceptable for computer simulation.
    • Acquiring PN Codes Without Serial Searches Using Modified Correlation Loops

      Yadati, Uday; Kosbar, Kurt; University of Missouri-Rolla (International Foundation for Telemetering, 1998-10)
      This paper analyzes the performance of a modified correlation, or delay-locked loop (DLL). These devices typically cross-correlate the received signal with a differentiated version of the originally transmitted signal. This paper describes some interesting properties the loop assumes when the differentiator is replaced by a Hilbert transform. The loop will still track the timing offset of the code, but it will also be able to acquire the signal when the initial offset is greater than one chip time. The new loop may also be superior to traditional DLL in low SNR environments, since it is much less likely to lose lock. Since the new loop is highly non-linear, it is studied through the use of computer simulations.
    • ACQUISITION STRATEGY ADAPTING TO TODAY’S TRENDS

      Colangelo, Ronald; Simulation, Training and Instrumentation Command (International Foundation for Telemetering, 1998-10)
      There is an acquisition management challenge to a program which has a limited market. One approach which can improve competition is the utilization of commercial technology. This utilization helps reduce unit cost and system obsolescence. The Hardened Subminiature Telemetry and Sensor System (HSTSS) has experienced the affects of a limited market and the need to utilize commercial technology. HSTSS plans to use partnering because the expertise is spread across the industry, and technology integration is required to fabricate an instrumentation system that would meet tri-service test requirements. There are many challenges facing the Program Manager; which create high program risk when proper acquisition procedures are not followed. HSTSS is this type of project. This paper will essentially discuss the acquisition strategy as it has evolved as well as the technical strategy. These strategies have been influenced by Government acquisition streamlining , available commercial technology and the programs limited production requirements. This is what the Government’s Project Managers are facing in these times of shrinking budgets and downsizing. The importance of the services working together, and sharing funds and technology to accomplish more with less is discussed in this paper. It is essential that government and industry work together as partners to reach the program’s goals. This paper proposes a program strategy based on our experience as to what is needed to incorporate partnering and commercial technology to successfully complete your program.
    • AN ADAPTIVE SIGNAL SEARCH ALGORITHM IN GPS RECEIVER

      Li, Sun; Yinfeng, Wang; Qishan, Zhang; Beijing University of Aeronautics and Astronautics (International Foundation for Telemetering, 1998-10)
      GPS signal fixed dwell and variable dwell time sequential search algorithms are compared with probability of false alarm and detection and searching rate. An adaptive search algorithm is proposed according to different work modes and interference or jam circumstance, which has effectively improved signal acquiring speed and reliability. Mathematical simulation shows its correction and feasible.
    • ALCATEL TELEMETRY TRANSMITTER AND BEACON TRANSMITTER (NEW GENERATION)

      Tonello, E.; Monica, G. Della; ALCATEL (International Foundation for Telemetering, 1998-10)
      Presentation for ITC 98 of Alcatel Espace last studies and developments regarding TTC Products This document lays on 3 parts: · a technical point of view · a technology/design description · a synthesis showing main performance and results
    • APPLICATION OF ADAPTIVE COMPUTING IN SATELLITE TELEMETRY PROCESSING

      Figueiredo, Marco; Graessle, Terry; Stinger Ghaffarian Technologies, Inc.; National Aeronautics Space Adminstration; Lockheed Martin Space Mission Systems & Services (International Foundation for Telemetering, 1998-10)
      The advent of adaptive computers built from re-programmable logic devices presents a potential solution for meeting the data processing requirements of the new era of Earth monitoring satellites to be launched by the National Aeronautics and Space Administration (NASA) Earth Science Enterprise project. The Earth Observing System (EOS) AM-1 spacecraft, the first satellite of this new era, will produce in only six months as much data as NASA has collected to this date. As a consequence, the Earth Science Data and Information System (ESDIS) project is building high performance and highly costly parallel processing systems to address the real-time data production requirements. Together with the high performance front-end ingest and level 0 processing microcircuits developed in-house at the Goddard Space Flight Center’s (GSFC) Data Systems Technology Division (DSTD), adaptive computers present a possible alternative to traditional CPU-based systems to increase the performance while reducing the cost of satellite telemetry processing systems. The Adaptive Scientific Data Processing (ASDP) project has been investigating the use of adaptive computers in the implementation of space borne scientific data processing systems. An order of magnitude processing speed acceleration over high-end workstations has been demonstrated for both level 1 and level 3 algorithms. This paper discusses the use of adaptive computing in satellite telemetry processing systems, level 1 and beyond. Primarily, it describes the efforts and presents the results of two prototypes developed by the ASDP project. The limitations of the current state of the technology are discussed and the expected improvements to facilitate the adoption of adaptive computers are presented. Finally, future work of the ASDP project is discussed.
    • Application of IP Multicasting to the NASA Communications Command and Telemetry Ground Network

      Spinolo, M. Chris; National Aeronautics and Space Administration (International Foundation for Telemetering, 1998-10)
      The NASA Communications (Nascom) Division has been directed to deploy Internet Protocol (IP) based technology for the ground segments of all present and future spaceflight telemetry networks. The Nascom network supports all NASA spaceflight telemetry, command and status requirements, from sounding rockets and balloons to the Hubble Space Telescope and the Space Shuttle. This paper discusses the challenges of transitioning a 35 year old, custom engineered, worldwide legacy telemetry network to IP, and the resulting, new NASA IP Operational Network for ground transport of spacecraft telemetry and command.
    • THE APPLICATION OF RADAR ENVIRONMENT SIMULATION TECHNOLOGY TO TELEMETRY SYSTEMS

      Kelkar, Anand; Gravelle, Luc; Malibu Research Associates (International Foundation for Telemetering, 1998-10)
      Complete real time testing of a telemetry tracking system typically requires the use of a cooperative target operating under conditions specially set up to simulate actual flight scenarios. This is a very expensive, time-consuming process and does not necessarily exercise all of the functions and capabilities available in new digital antenna controllers. This paper introduces Radar Environment Simulator technology and its application to testing of telemetry tracking systems. Measured results are shown, demonstrating that operational environment simulation is a valuable approach to quickly and effectively characterize the real time operation of a telemetry tracking system.
    • APPROACH FOR A WIDE DEVIATION RF PHASE MODULATOR on a 6U-VME-CARD

      Weitzman, Jonathan M; GDP Space Systems (International Foundation for Telemetering, 1998-10)
      A Phase Modulator combining digital techniques with non-traditional analog circuitry can minimize the shortcomings of a traditional (purely analog) Phase Modulator. These shortcomings are: nonlinear response from input modulating signal to output modulated signal; parameters (frequency and modulation index) that are difficult to set; and the need for complex filters. The design approach discussed in this paper uses a combination of Direct Digital Synthesis (DDS) and analog devices operating in their linear range to generate a Phase Modulated RF (140 MHz) signal. A Numerically Controlled Oscillator (NCO) digitally generates the first IF yielding a very accurate, repeatable and linear signal with easily adjustable parameters such as frequency and modulation index. Linear multipliers (instead of saturated diode mixers or step recovery diodes) are used for up-conversion to RF. Using linear multipliers eases the filtering requirements due to the significantly reduced harmonics and IM (Inter-Modulation) terms. The resulting RF signal is easily translated to higher frequency bands such as L, S, C, X or K.
    • Automatic Gain Control and Doppler Motion Models in LabVIEW

      Laird, Daniel T.; Edwards Air Force Base (International Foundation for Telemetering, 1998-10)
      A simplex or ‘passive’ continuous wave and monopulse seeker tracks specific attributes of a target’s radio frequency (RF) radar return in some coordinate frame. In particular, a return carries dynamic information in amplitude (ω) and frequency (ω) at some point in azimuth (r,θ) and elevation (r,θ) planes. A passive seeker requires an illuminator beam, I(ω,φ,θ), and may require a frequency modulation on the illuminator. To model a simplex target return, we have based the dynamics on a point source radar cross section (RCS) along a line of sight (LoS) radial. The Az and El angles are equivalent to antenna placement, the attenuation and frequency dynamics are modeled in commercial off-the-shelf (COTS) software.
    • BANDWIDTH DRIVEN TELEMETRY

      Jones, Charles H.; Gardner, Lee S.; Edwards Air Force Base (International Foundation for Telemetering, 1998-10)
      “The radio frequency spectrum is a limited natural resource; therefore, efficient use of available spectrum is mandatory.” IRIG Standard 106-96 [4] As the availability of the frequency spectrum decreases and demands for bandwidth from users increases, the telemetry community will have to find ways to use spectrum efficiently. This paper is an overview of the major areas of research that promise potential increases in the efficient use of the telemetry spectrum. The discussion is summarized in a matrix that compares potential gains with overall costs for each research area using relative values of high, medium, and low.
    • A C-BAND MOBILE TELEMETRY SYSTEM

      Wei, Zeng; Beijing Research Institute of Telemetry (International Foundation for Telemetering, 1998-10)
      In this paper, it is introduced that a C-Band mobile telemetry system designed for the satellite telemetry task. It can provide a wide range of bit rate and different code type and frame format which is completely set up by user in advance, to meet the requirements needs in different satellites. The PCM-PSK-PM signal and the PPM-MFSK-PM signal can be received and demodulated at the same time. Single channel monopulse technique is employed for automatic tracking. Angle calibration and angle tracking are performed in this system. Real-time data processing, displaying, testing of bit error rate and post-flight analyses is performed by PC type computer. All key components of the system may be programmed.
    • Calendars and Current Calendar Issues: Year 2000 and GPS 1999 Week Number Roll Over

      Claflin, Ray, III; Claflin Associates (International Foundation for Telemetering, 1998-10)
      This paper will present a selected overview of calendars and calendar development from antiquity to the current Gregorian calendar. The current hot topics of the GPS 1999 Rollover and the Year 2000 Millennium Rollover will be explained.
    • CONVERSION FROM ENGINEERING UNITS TO TELEMETRY COUNTS ON DRYDEN FLIGHT SIMULATORS

      Fantini, Jay A.; Woodside Summit Group Incorporated (International Foundation for Telemetering, 1998-10)
      Dryden real-time flight simulators encompass the simulation of pulse code modulation (PCM) telemetry signals. This paper presents a new method whereby the calibration polynomial (from first to sixth order), representing the conversion from counts to engineering units (EU), is numerically inverted in real time. The result is less than onecount error for valid EU inputs. The Newton-Raphson method is used to numerically invert the polynomial. A reverse linear interpolation between the EU limits is used to obtain an initial value for the desired telemetry count. The method presented here is not new. What is new is how classical numerical techniques are optimized to take advantage of modern computer power to perform the desired calculations in real time. This technique makes the method simple to understand and implement. There are no interpolation tables to store in memory as in traditional methods. The NASA F-15 simulation converts and transmits over 1000 parameters at 80 times/sec. This paper presents algorithm development, FORTRAN code, and performance results.
    • THE DESIGN AND CONSTRUCTION OF A C-BAND RAIL-SAR AND AN S-BAND DOPPLER RADAR

      Crockett, Donald E.; Arnold, David V.; Jensen, Michael A.; Brigham Young University (International Foundation for Telemetering, 1998-10)
      To help students learn the principles of microwave engineering and electromagnetic theory, labs were developed in which the students built a rail-synthetic aperture radar(SAR) and a Doppler radar. These labs gave the students practical experience in the paper design, simulation, construction, testing, and debugging of RF circuits. This paper includes a description of the design, physical construction, the basic operation, and the results from these projects.
    • DESIGN AND PERFORMANCE OF A MULTI-MODE RECEIVER CARD

      O’Cull, Douglas C.; Microdyne Communications Technologies, Inc. (International Foundation for Telemetering, 1998-10)
      This paper will discuss the design and performance of a multi-mode receiver. The receiver is designed to operate in standard VME and PC environments and will support data rates up to 20 Mbps. The paper will discuss new digital demodulation techniques that support PCM-FM, PCM-PM, FM, PM, BPSK, QPSK and O-QPSK modulation. This new demodulator also includes a built in bit sync with soft decision outputs. This paper will provide an overview on digital filtering used in the second IF filter which provides dynamic changing of the IF bandwidth.
    • DESIGN AND PERFORMANCE OF A SATELLITE TT&C RECEIVER CARD

      O’Cull, Douglas C.; Microdyne Corporation (International Foundation for Telemetering, 1998-10)
      Today’s increased satellite usage has placed an increased demand for high performance low cost satellite TT&C receiver systems. Many of the receiver systems being installed are using VME or PC platforms to provide streamlined computer based installations. This paper will describe the design and performance of a VME/PC based satellite TT&C receiver. The paper will provide a block level description of a 70 MHz receiver which uses a PM/FM digital demodulator. The paper will also provide performance data for a PM/BPSK sub-carrier satellite application.
    • DESIGN AND TESTING OF A SIMPLE OPTICAL FIBER TELEMETRY LINK FOR USE IN RUGGED ENVIRONMENTS

      Weis, R. Stephen; Bachim, Brent L.; Texas Christian University (International Foundation for Telemetering, 1998-10)
      The design and testing of an optical fiber telemetry link for use in rugged environments is described. Several potential applications for this cost effective telemetry link built from readily available components are given. The results of testing the simple telemetry link for vibrations up to 20g and temperatures up to 150° C are reported.