• CARRIER PHASE MODULATION USING DIRECT DIGITAL SYNTHESIS FOR AN S-BAND UPLINK

      Burgess, George; Murphy, William; Stanford Telecommunications, Inc. (International Foundation for Telemetering, 1991-11)
      Phase modulation has traditionally been performed in analog hardware. A new product will be described that implements this function using a phase-modulating NCO IC. The modulating signal is sampled and added digitally to the phase of the carrier generated by the NCO. This method produces an output spectrum with highly accurate modulation control, low spur levels and minimal distortion. The effects of generating sampled phase-modulated signals will be described. The selection of the clock and output frequencies are critical to ensuring a clean spectrum. Resulting output spectra are shown.
    • REAL-TIME TELEMETRY DATA PROCESSING and LARGE SCALE PROCESSORS

      Dreibelbis, Harold N.; Kelsch, Dennis; James, Larry; H.D. Consultants, Ltd; CRAY Research, Inc.; LPJ Engineering (International Foundation for Telemetering, 1991-11)
      Real-time data processing of telemetry data has evolved from a highly centralized single large scale computer system to multiple mini-computers or super mini-computers tied together in a loosely coupled distributed network. Each mini-computer or super mini-computer essentially performing a single function in the real-time processing sequence of events. The reasons in the past for this evolution are many and varied. This paper will review some of the more significant factors in that evolution and will present some alternatives to a fully distributed mini-computer network that appear to offer significant real-time data processing advantages.
    • THE REAL/STAR 2000: A HIGH PERFORMANCE MULTIPROCESSOR COMPUTER FOR TELEMETRY APPLICATIONS

      Furht, B.; Gluch, D.; Parker, J.; Matthews, P.; Joseph, D.; Modular Computer Systems, Inc. (International Foundation for Telemetering, 1991-11)
      In this paper we describe the design of the REAL/STAR 2000 system, a highperformance real-time computer for telemetry applications. The REAL/STAR 2000 is a symmetric, tightly-coupled multiprocessor, optimized for real-time processing. The system provides a high level of scalability and flexibility by supporting three configurations: single, dual, and quad processor configurations, based on Motorola 88100 RISC processors. The system runs the multiprocessor REAL/IX operating system, a real-time implementation of the AT&T UNIX System V. It compiles with BCS and OCS standards, meets the POSIX 1003.1 standard, and has the current functionality of the emerging POSIX 1003.4 real-time standard. The REAL/STAR 2000 promotes an open system approach to real-time computing by supporting major industry standards. Benchmark results are also presented in the paper.
    • A GENERIC OBJECT-ORIENTED DESIGN FOR A RADIO FREQUENCY SIMULATION IN A SPACE TELEMETRY AND COMMAND ENVIRONMENT

      Policella, Joseph; CAE-Link Corporation (International Foundation for Telemetering, 1991-11)
      In a generic telemetry simulation the overall fidelity of the simulation is largely based on the simulated vehicle’s On-Board-Systems (OBS) engineering models that drive the generation of the telemetry. Also, the actual transfer of data between the simulated vehicle and control center depends on the ability of the Radio Frequency (RF) OBS to acquire and process the RF links thus resulting in a Acquisition of Signal or Loss of Signal (AOS/LOS) determination. The simulated RF links are a function of the communications OBS models, and the communications environment models. The communications OBS models are responsible for propagating the RF signal. Since the RF link analysis is highly integrated into the characteristics of the communications equipment and environment models, RF link software needs to be constantly redeveloped as communications equipment models change, fidelity is added, or multiple links are created. However, by using a generic objectoriented design, RF link software can process any number of differing links based on the RF characteristics of the propagated wave. As a result, the communications equipment model software can be changed to reflect possible design changes without having to rewrite the RF link software thus allowing reuse of existing code.
    • ON IMPLEMENTATION OF REMOTELY OPERATED UNMANNED TELEMETRY TRACKING SYSTEMS WITH FIBER OPTIC CABLE

      TURNER, WILLIAM C.; ELECTRO-MAGNETIC PROCESSES, INC. (International Foundation for Telemetering, 1991-11)
      The high cost of real estate in countries with expanding populations, coupled with the long range capability of modern weapon systems has resulted in the need to expand test ranges to remote desert areas or areas over sea water. In order to preclude the cost of duplicating existing test centers, and the high cost of manually operating ground tracking stations, the requirement for unmanned remotely controlled telemetry tracking systems has emerged. Until recently, implementation of such systems has been trivial because the microwave link had sufficient bandwidth. However, with the advent of multi-TM bands, encrypted T.V. video and dual-polarization diversity requirements, implementation of unmanned remote stations has become cumbersome, expensive and less reliable. For instance, a pair of dedicated computers are now required to remotely control as many as eight receivers and four diversity combiners. This paper analyzes the advantages, limitations and feasibility of remotely controlling a wide-band antenna/pedestal with the restriction that all frequency downconverters, receivers, and combiners be located at the test center where they can be manually controlled and monitored, and more readily maintained. A comparison is made between the use of coaxial cable and fiber-optic cable as short-haul (0.25 to 25 kilometers) RF transmission media.
    • A Real-time Counting-measuring Method for PPM(PPK) Signals

      Xi-Hua, Li; Xinan Electronic Engineering Institute, China (International Foundation for Telemetering, 1991-11)
      On the disscussion of custom real-time counting-measuring method, this paper presents a new method suitable for the working condition of non-man duty, which possesses the feature of 100ns counting-measuring accuracy and high fidelity. In addition, the concept of “Signal-time/digit converter” is proposed for the first time and the principle and working procedure of this method are introduced in brief.
    • A SIMULATOR OF PCM STREAM WITH HIGH DATA RATE

      Liang, LI Xian; QiShan, Zhang; Hui, Yang; BEIJING UNIVERSITY OF AERONAUTICS AND ASTRONAUTICS (International Foundation for Telemetering, 1991-11)
      The simulator of PCM data stream is an important apparatus. Without an advanced high data rate simulator, were not there a PCM system with advanced performance. After careful study, a simulator in laboratory of PCM stream with the data rate up to 30 Mbps is now designed. Our simulator differs from the traditional ones in the design principle and can bring all potentialities into play. It is more powerful in function, easier to test and more accurate in control. In the meanwhile, it can keep compatible with old simulators.
    • INTERFRAME CODING OF VIDEO TELEMETRY SIGNALS

      Deutermann, Alan R.; Schaphorst, Richard A. (International Foundation for Telemetering, 1991-11)
      Television signals have been digitally transmitted for telemetry applications for several years. Reasons for digital transmission include the need for encryption, bandwidth compression, and the efficiency of time division multiplex. All digital coding techniques which have been employed to date, for video telemetry, are based on intraframe technology. In this case each TV frame is coded independently of the previous frames. In most video telemetry scenes there is a high degree of correlation between adjacent TV frames, and an interframe coding system which compresses the signal by reducing this frame-to-frame redundancy should be effective. This paper explores the potential advantages of interframe coding for video telemetry. Since this high level of compression typically causes the transmitted signal to be more sensitive to data link errors, the paper also examines advanced error control techniques.
    • RF SPECTRAL CHARACTERISTICS OF RANDOM PCM/FM AND PSK SIGNALS

      Law, E.L.; Pacific Missile Test Center (International Foundation for Telemetering, 1991-11)
      The telemetry radio frequency (RF) spectrum is rapidly becoming more crowded. Therefore, telemetry system engineers and frequency managers must become more knowledgeable about the RF spectral characteristics of telemetry signals. This paper presents methods to calculate the expected RF spectrum of random non-return-to-zero (NRZ) pulse code modulation (PCM)/frequency modulation (FM) and phase shift key (PSK) signals. The discussion includes the effects of bit rate, peak deviation, premodulation filtering, and spectrum analyzer resolution bandwidth. The methods are easily implemented using a personal computer and a spreadsheet program with graphics capability. Calculated spectra agree well with measured spectra. Equations are presented for accurately estimating the peak deviation and unmodulated carrier power of a random NRZ PCM/FM signal from the measured RF spectrum. Adjacent channel interference is also calculated. Key words: radio frequency spectral occupancy, pulse code modulation, frequency modulation, phase shift keying, premodulation filtering, adjacent channel interference.
    • TELEMETRY IN TESTING OF UNDERSEAS WEAPONS

      Hull, Roy T., Jr.; Naval Undersea Warfare Engineering Station (International Foundation for Telemetering, 1991-11)
      The performance testing of underseas weapons involves many of the same challenges as for other “smart” systems. Data sets on the order of GigaBytes must be extracted, processed, analyzed, and stored. A few KiloBytes of significant information must be efficiently identified and accessed for analysis out of the great mass of data. Data from various sources must be time correlated and fused together to allow full analysis of the complex interactions which lead to a given test result. The fact that the various sources all use different formats and medias just adds to the fun. Testing of underseas weapons also involves some unique problems. Since real time data transmission is not practical; the vast bulk of the test data is recorded and then recovered with the vehicle at the end of the test. Acoustics are relied on for identification and ranging. As systems continue to get smarter; the rates, capacities, and “smarts” of the equipment and software used to process test data must similarly increase. The NUWES telemetry capabilities developed to test and analyze underseas weapons could be of use on other government related projects. “Key words: Telemetry, data processing, data analysis, undersea weapons, smart weapons, torpedoes, performance testing.”
    • EVOLUTION OF THE DOD GLOBAL SPACE TEST CAPABILITY

      Grogan, James L., III; Fricks, Robert E. (International Foundation for Telemetering, 1991-11)
      This paper is an overview of progress toward a more formalized military space test range capability. It reviews the motivation for a space test function, relates history which has led to the contemporary space test operation, scopes existing space test pursuits and projects a direction for future activity. Its intent is to baseline the status of the current space test program and to present one vision for its future evolution.
    • FARADAY CUP SYSTEM CONTROL LOGIC ON THE WIND SPACECRAFT

      Mavretic, Anton; Konstantinidis, Anastasios; Gergin, Emile; Zhou, Runde; Boston University (International Foundation for Telemetering, 1991-11)
      A satellite-mounted instrument has been developed to measure the energy spectrum of the solar proton flux in the solar wind. The instrument consists of a sensor --- the Faraday Cup, an analog signal processing chain, a high voltage modulator and a digital section. This paper presents the digital section designed and built in our laboratory which functions well to (a) interface with the main processor, (b) to provide the logic signals with proper timing to the analog circuitry, (c) to deliver the necessary bit pattern to the high voltage modulator, (d) to provide the calibration mode control signals when necessary, and (e) to synchronize the sequence of events at the begining of every spacecraft rotation. As with all space projects primary concerns beyond the logical functionality consistes of circuit power consumption, instrumental mass, radiation tolerance levels, stability with respect to temperature, and relative ease of component procurement. The NASA WIND laboratory spacecraft that will carry the experiment is due to be launched in December of 1992 and eventually come to park in an orbit at the first Lagrangian point.
    • THE BRIDGE FUNCTION TELEMETRY SYSTEM

      Qishan, Zhang; BEIJING UNIVERSITY OF AERONAUTICS AND ASTRONAUTICS (International Foundation for Telemetering, 1991-11)
      Based on the theory of orthogonality, two orthogonal multiplex systems called frequency division multiplexing (FDM) and time division multiplexing (TDM) have long been developed. Therefore, many people tend to think that these two systems represent the ONLY two multiplexing methods that satisfy the orthogonal condition. However, after years of research, we've discovered a new kind of orthogonal functions called Bridge functions. The Bridge functions have the every promise of being the basis for constructing an entirely new kind of telemetry system, which has been named as sequency division multiplexing (SDM). Since the Bridge functions are the mathematical basis of the new telemetry system, we will give a summary of the Bridge functions at first. We have successfully constructed an experimental prototype called BAM-FM system in our laboratory. The main ideas, block diagram, operational principles, and technical problems are discussed in this paper. All our work has proved that SDM has not only research interests, but also practical value.
    • A GUI BASED SYSTEM FOR AUTOMATIC CONSTRUCTION OF ENGINEERING MODEL SOFTWARE FOR COMMAND RESPONSE AND TELEMETRY GENERATION

      Parlanti, Joe; Pinkerton, Ronnie; CAE-Link Corporation (International Foundation for Telemetering, 1991-11)
      There exists today, numerous off-the-shelf hardware solutions for the generation of simulated telemetry data streams. The ability to rapidly develop engineering models to drive the data contents of the telemetry is restricted by the lack of contemporary CASE tools. This paper presents an object-oriented Graphical User Interface (GUI) approach to generation of mathematical models in order to reduce the time required for model generation to a fraction of today’s development time, eliminate the need to write substantial amounts of software, and allow reuse of model objects in a manner consistent with the GUI cut, paste, and copy metaphors.
    • SIGNAL TRANSMISSION FROM REMOTE TELEMETRY ANTENNAS USING WIDEBAND ANALOG FIBER OPTIC LINKS

      Matsuo, A.T.; Law, E.L.; Pacific Missile Test Center (International Foundation for Telemetering, 1991-11)
      This paper will present the results of an investigation of the feasibility of using broadband analog fiber optic technology to send telemetry antenna outputs from remote sites to a central site. The fiber optic hardware consisted of a prototype analog fiber optic transmitter and receiver plus 10 km of single-mode fiber. Laboratory tests were performed to simulate the performance in the real-world. The fiber optic system had a noise figure of 33.5 dB and a third order intercept point of 16.75 dBm. The use of this fiber optic system to transmit a 215-320 MHZ telemetry antenna downconverter output over a 10 km fiber would only degrade the quality of real-world telemetry signals by a few tenths of a decibel. Key words: analog fiber optic transmission, remote telemetry antennas.
    • GLOBAL POSITIONING SYSTEM TELECOMMAND LINK

      Alves, Jr., Daniel F.; Alpha Instrumentation and Information Management (International Foundation for Telemetering, 1991-11)
      The Global Positioning System of satellites and pseudosatellite ground stations (GPS) is designed to provide very accurate Time, Space, and Position Information throughout the entire world. It is also being used to provide such information to unmanned vehicles operating on test ranges throughout the United States, as a replacement/ adjunct for tracking radar as well as a form of guidance. What is proposed in this paper, for which a patent has been applied, is that the existing L-Band RF link carry command information, when required, as well as TSPI information.
    • A TOOL FOR PERFORMANCE EVALUATION OF REAL-TIME UNIX OPERATING SYSTEMS

      Furht, B.; Boujarwah, A.; Gluch, D.; Joseph, D.; Kamath, D.; Matthews, P.; McCarty, M.; Stoehr, R.; Sureswaran, R.; Modular Computer Systems, Inc. (International Foundation for Telemetering, 1991-11)
      In this paper we present the REAL/STONE Real-Time Tester, a tool for performance evaluation of real-time UNIX operating systems. The REAL/STONE Real-Time Tester is a synthetic benchmark that simulates a typical real-time environment. The tool performs typical real-time operations, such as: (a) reads data from an external source and accesses it periodically, (b) processes data through a number of real-time processes, and © displays the final data. This study can help users in selecting the most-effective real-time UNIX operating system for a given application.
    • FDDI AS AN EMERGING STANDARD FOR TELEMETRY SYSTEMS

      Taylor, Gene; Vista Controls Corporation (International Foundation for Telemetering, 1991-11)
      Various high performance fiber optic networks have been in existence and available now for over 10 years. Virtually all of them, until recently, have been designed around the “better idea” of some single company or engineer, and therefore were or became expensive, proprietary systems, with limited support, and limited or no growth potential. Many benefits were still realized by the users in spite of that; primarily in the areas of increased bandwidth, improved security, and the capability to have data transmission over long distances. However, after 5 years of continued development and refinement, the American National Standards Institute (ANSI) X3T9.5 committee has nearly completed acceptance and final approval of the Fiber Data Distributed Interface (FDDI) specifications. The new FDDI standards have already evidenced a tremendous and eager acceptance by the end user community, and are clearly destined to replace Ethernet as the most prevalent network media. FDDI also offers additional benefits specifically of interest to the telemetry market, and therefore represents an ideal Local Area Network (LAN) technology towards which any TM installation should migrate.
    • AN AUTOMATED TESTING SYSTEM FOR A TELEMETRY TRACKING SYSTEM

      MARSH, TED A.; INSTRUMENTATION DIRECTORATE (International Foundation for Telemetering, 1991-11)
      White Sands Missile Range (WSMR) has developed an Advanced Transportable Telemetry Acquisition System (TTAS-A) which utilizes a dedicated computer system for antenna control. The Automated Testing System (ATS), an integral part of this system, is the subject of this paper. The ATS consists of hardware and software designed to provide fully automated testing of the radio frequency (RF) and servo subsystems for validation purposes. The RF subsystem tests are designed to evaluate, measure, and display RF performance parameters such as receiving system Figure of Merit and RF system sensitivity. The servo subsystem tests are designed to evaluate and display the stability and response characteristics of the servo subsystem. Tests are accessed via a keyboard, and extensive use of menus makes the software easy to learn and use. The test equipment is controlled entirely by the computer, and hard copies of all test results are available on the system printer.
    • NETWORK MANAGEMENT TOOLS FOR A GPS DATALINK NETWORK

      Smyth, Padhraic; Chauvin, Todd; Oliver, Gordon; Statman, Joseph; Jet Propulsion Laboratory (International Foundation for Telemetering, 1991-11)
      The availability of GPS (Global Position Satellite) information in real-time via the RAJPO Datalink system will significantly increase the capacity of flight test and training ranges in terms of missions supported. This increase in mission activity will in turn impose more demands on mission planning in the range operations environment. In this context, network management tools which can improve the capability of range personnel to plan, monitor, and control network resources, are of significant interest. In this paper we describe the application of both simulation and artificial intelligence techniques to develop such network management tools.