• TIPS - An Integrated Solution for Multi-Mission Telemetry

      Van Dolsen, L. L.; System Development Corporation (International Foundation for Telemetering, 1978-11)
      The Air Force Space and Missile Test Center (SAMTEC) must provide concurrent support for a variety of missions requiring real time telemetry data acquisition and processing. An integrated system is presently going operational to replace seven individual complexes presently supporting these missions. The Telemetry Integrated Processing System (TIPS) includes six real-time input streams, a large-scale near-real-time processor, and six interactive display areas. The TIPS facilitates rapid reconfiguration to meet changing operational needs or to continue operation in the face of equipment failures. The cost and lead time required for support of new requirements and also operation and maintenance costs will be substantially reduced. TIPS is the first Air Force data system processed under the Design-to-Cost/Life Cycle Cost (DTC/LCC) philosophy; all design and specification changes are evaluated in terms of operational as well as initial costs. Notable achievements in the TIPS implementation are the Telemetry Compiler and the real-time acquisition and processing subsystems which are described in accompanying papers.
    • Advanced Marine Information Delivery

      Durstenfeld, Richard; NASA Jet Propulsion Laboratory (International Foundation for Telemetering, 1978-11)
      SEASAT-1 is now an established fact. It is providing continuous sensing of the world's oceans and related meteorological phenomena from its satellite platform in space. What is the next step? This paper considers the information delivery challenges of the follow-on programs to SEASAT as they progress through the next decade. These include coping with the vast quantities of data to be transferred, fulfilling the temporal requirements on data delivery, and the trade-offs and developments needed to accomplish the various levels of processing required to convert sensor output into useful information. A need for critical development is clearly identifiable in the areas of low cost ground terminals capable of image extraction and image correlation; dynamic data assimilation to accomodate forecasters; low resolution onboard correlators; and low cost user advisory (display) terminals. The system planners for the Ocean Satellite advanced programs are utilizing an end-to-end data systems approach in meeting these challenges. The economic and scientific impact of delivering decision making information to the marine community in real time and in useful form is recognized and is potentially achievable.
    • Quantization for Signal Detection and Representation

      Kassam, Saleem A.; University of Pennsylvania (International Foundation for Telemetering, 1978-11)
      For digital representation of analog data the minimum mean-squared-error criterion is commonly used as a criterion for the basis of optimum quantizer design. In this paper we show that in some situations measures other than the minimum mean-squared-error may be more appropriate. For the signal representation problem, it is shown that the mean-absolute-error criterion has theoretical justification, as again for some signal detection problems it is shown that the mean-squared-error criterion is not the most appropriate criterion.
    • International Telemetering Conference Proceedings, Volume 14 (1978)

      International Foundation for Telemetering, 1978-11
    • A Flexible User Oriented Approach to Communications Systems Simulation

      Fashano, M.; Austin, M. C.; Hughes Aircraft Company (International Foundation for Telemetering, 1978-11)
      An advanced software/hardware computer system developed for the simulation of communications systems is described. This user oriented system allows for flexible and efficient modeling and simulation of complex communications systems. Excellent agreement between simulation and measured results has consistently valididated the simulation approach.
    • Optimum Quantization for Minimum Distortion

      Caprio, James R.; Westin, Nancy; Esposito, John; Comptek Research, Inc.; State University of N.Y. at Buffalo (International Foundation for Telemetering, 1978-11)
      This paper treats the problem of optimal selection of data quantization levels for minimum error. No assumptions are made regarding the underlying statistics of the process to be quantized. A finite precursor sample of the data is analyzed to infer the underlying distribution. Selection of optimum quantization levels can then be related to the generation of an optimum histogram for the data record. The optimum histogram is obtained by a dynamic programming approach for both least mean square error and minimum Chebychev error criteria. Transmitted data can then be quantized according to levels specified by the histogram. The process can be repeated periodically either with a new data sample, if the underlying process is nonstationary, or performed on the accumulated record in the stationary case.
    • INTELSAT V Spacecraft Antenna Subsystem

      Jakstys, V. J.; Ward, H. T.; Ford Aerospace and Communications Corporation (International Foundation for Telemetering, 1978-11)
      Design and development has been completed on the Antenna Subsystem for the INTELSAT V Communications Satellite. The Communications antennas include two C-Band (transmit and receive) Hemi/Zone coverage antennas, two C-Band (transmit and receive) Earth Coverage antennas, two 11/14 GHz Spot Beam antennas and an 11 GHz Beacon antenna. The C-Band Telemetry and Command antennas consist of two directional beam telemetry (transmit) antennas, a dual-port toroidal beam telemetry antenna and two cardioid beam command (receive) antennas. The designs have been verified by measurements, and the test results indicate that all major performance requirements will be achieved.
    • TDRSS - User Satellite Acquisition and Tracking

      Franklin, S. B.; TRW Defense and Space Systems Group (International Foundation for Telemetering, 1978-11)
      The Tracking and Data Relay Satellite System (TDRSS) will provide communications and tracking services to the Space Shuttle and most other NASA missions of the 1980's. Relay services are provided between NASA's near earth satellites and a ground terminal at White Sands, N.M. via synchronous Tracking and Data Relay Satellites. Establishing and maintaining the communications links is a complex task which includes spatial, signal and data acquisition involving crosslinks between the TDRS and NASA's user satellites. Concepts and capabilities are presented for antenna acquisition, and for PN code and carrier acquisition. Total acquisition times, including bit synchronizer and decoder acquisition are also provided.
    • Satellite, Surface, and Subsurface Optical Communications

      Mooradian, G. C.; Naval Ocean Systems Center (International Foundation for Telemetering, 1978-11)
      Optical communication in the atmosphere, space, the marine boundary layer, and underwater are being investigated for a variety of applications. Three classes of optical communications systems will be addressed: OCULT (Optical Communications Using Laser Transceivers), ELOS (Extended Line-of-Sight) optical communications and satellite to subsurface optical communications. OCULT is a 10.6μ high rate reciprocal tracking heterodyne laser communications system designed for nearly all-weather duplex video bandwidth communications to horizon limited ranges. Of special interest are effects of coherent propagation through fogs and turbulence. The ELOS system is a 1.06μ optical aerosol scatter communications system for ranges of 30 to 300 miles. Scattering measurement at 40 to 80 miles through the marine boundary layer will be presented. The satellite to subsurface communication efforts deal with blue/green transmission from a satellite, through the atmosphere (including clouds) to a submerged receiver, exploiting the blue/green "window" in ocean water. The multiple forward scattered and diffusion transport of serm-plane waves through clouds and ocean waters will be discussed.
    • Telemetry - Past, Present, Future

      Strock, O. J. "Jud"; EMR-Telemetry (International Foundation for Telemetering, 1978-11)
      On the assumption that "the past is prologue", this paper presents an interesting and revealing look at the telemetry technology of twenty years ago, a comparison of that with the technology of today, and an extrapolation into the future of telemetry. Factors which are examined include the characteristics of telemetry systems, the price per unit of performance, and the applications in which telemetry has been, is being, and likely will be used. The key word in the paper is "choice". A user or prospective user had little choice in equipment or techniques twenty years ago; the present day technology offers a wide range of choices; indications are that the future will offer even greater choices in characteristics and price - and consequently, in the applications for which telemetry is a viable tool for data acquisition and processing.
    • FET Amplifiers for Communications Applications

      Kennedy, W. Keith, Jr.; Watkins-Johnson Company (International Foundation for Telemetering, 1978-11)
      The Field Effect Transistor (FET) is revolutionizing microwave communications with both its low noise performance and high dynamic range. This paper emphasizes developed amplifier hardware available today for both ground and satellite applications. The focus is on the noise figures and output powers available from 4 to 15 GHz.
    • A Concept for a Transparent Data Acquisition and Distribution System for Spaceflight Applications

      Greene, Edward P.; NASA/Goddard Space Flight Center (International Foundation for Telemetering, 1978-11)
      The emergence of "smart" sensors onboard space missions is forcing a reexamination of the procedures by which NASA acquires, multiplexes, transmits, annotates, and distributes sensor data to the user community. Increasingly we find that "smart" sensors are being planned for future space missions which will search for specific unusual phenomena and, when present, record these phenomena in great detail. This gives rise to the need for a widely varying bandwidth requirement from each instrument in response to the occurrence of phenomena that cannot be anticipated in advance. An asynchronously multiplexed packet telemetry concept is described which, within broad limits, permits instruments to acquire and transmit information at the rate appropriate for the experimental phenomena being observed. Data from a single instrument, along with the necessary ancillary data (typically time, position, and attitude), will be assembled into self-contained packets and will be subsequently transmitted over various communications links (i.e., space telemetry channel, ground communications circuits, etc.) to the experimenter's facility in near real time. Reliable error control coding will be included in each link transmission to protect the integrity of the data packets. A major objective is to make the entire data acquisition and distribution process completely transparent to the experimenter in the sense that the output terminal of the distribution system will be physically, logically, and electrically identical to that of the experiment output channel. To provide greater inter-mission portability of instruments and to reduce the instrument interfacing costs, the emerging national and international telecommunications standards (ADCCP/HDLC/SDLC, X.25, etc.) will be utilized as the instrument interface standards wherever practical. Except for the time delay imposed by propagation and nominal queueing considerations, the experimenters will observe an interface identical to that which would occur if the instrument were physically located at their facilities.
    • Computer Controlled Testing of Telemetry Ground Stations

      Law, Eugene L.; Pacific Missile Test Center (International Foundation for Telemetering, 1978-11)
      The testing of telemetry ground stations by manual methods can be very time consuming. The test time can be reduced by using an automated test system. A minicomputer controlled test system is described and is shown to provide accurate, repeatable results and to reduce the test time to about one-fifth of the manual test time.
    • The Navstar Global Positioning System Control Segment Performance During the First Year

      Schaibly, John H.; General Dynamics (International Foundation for Telemetering, 1978-11)
      This paper reports the preliminary performance of the Navstar Global Positioning System Control Segment (CS) during the period July 1977 through July 1978. During this period, three navigation satellites were launched and were tracked and uploaded by the CS. An overview of the CS is presented as well as a summary of the present system status. User performance, total system performance, and CS performance are discussed, and methods for determining the latter are described. Performance measures including first measurement residuals and predicted pseudorange error for NTS 2 and first measurement statistics, predicted User Range Error, ephemeris prediction error, and predicted clock error for the NDS satellites are presented. The preliminary performance results presented are very good considering the early stage of multi-satellite tracking. Projecting the two satellite performance to four satellites, the CS contribution to user navigation error is 12.8-20.5 meters at 2 hours. This error consists of ephemeris and clock prediction errors of approximately 3.5 and 4.5 meters, respectively.
    • VLSI Memories Problems and Promise from a Military Viewpoint

      Vail, Patrick J.; Hanscom AFB (International Foundation for Telemetering, 1978-11)
      Many of the problems that military magnetic and mechanical memories experience can be overcome by using Very-Large-Scale-Integrated (VLSI) circuits. These VLSI memories can present problems of their own, however. This paper outlines an assessment of the state-of-the-art in military memories that was performed to identify VLSI memory technology gaps that need additional development effort.
    • Genesis and Design of the Tracking, Telemetry, and Command System for the Navstar Global Positioning System

      Hoff, Charles S.; The Aerospace Corporation (International Foundation for Telemetering, 1978-11)
      The genesis and design of a unique Tracking, Telemetry, and Command (TT&C) System for the Navstar Global Positioning System (GPS) is described from the perspective of the System Architect/Engineer. Working from the diverse and sometimes conflicting mission requirements, derivative performance requirements for the TT&C System were generated. System design tradeoffs were performed in an effort to compromise conflicting requirements which affected the frequency domain, link budgets, antenna sizing, and modulation schemes. The characteristics of the resulting TT&C System included the following: a. Primary uplinking to the satellite on a spread spectrum secure link at X-Band. b. Use of a closed-loop uplink which takes advantage of existing onboard functions as references to achieve precise ground-space synchronization. c. Incorporation of state-of-the-art error control techniques to achieve high net data throughputs with concurrently "zero error" data transfer from ground to space. d. Hybrid frequency ground antennas to accommodate both the primary and backup command links, with compatible telemetry downlinks. A common S-Band frequency input within the satellite to both the primary wideband Pseudo Random Noise (PRN) correlation receiver and the backup Space Ground Link System (SGLS) receiver.
    • A Solid State Data Recorder for Spacecraft Telemetry Applications

      Stermer, Robert L, Jr.; NASA Langley Research Center (International Foundation for Telemetering, 1978-11)
      A Solid State Data Recorder (SSDR) has been developed which offers a high reliability alternative to tape recorders in many spacecraft telemetry applications. The storage medium used in this recorder was ferrimagnetic garnet films supporting nonvolatile magnetic "bubble" domains. This technology is very flexible and permits a recorder design which can simplify much of the interface with the telemetry system. The recorder was designed using modular construction consisting of a Digital Control Unit (DCU), Power Supply, and two Memory Modules. The Digital Control Unit (DCU) is made up of four independent microprocessor controlled data channels, configuration control, and a telemetry and test interface. The configuration can be programed so that the SSDR can operate as a 1, 2, or 4 serial channel recorder, or a single 8-bit parallel channel configuration. Each channel has a complete command set and can operate independently of the other channels. Details of the system organization and operational characteristics are presented. The Memory Module was designed with 32 magnetic assemblies, or cells, each containing 16 serial 102.4K bit magnetic "bubble" memory chips. Sense and operator electronics, and field coil drive electronics are also located in the memory module. A prototype SSDR has been fabricated. This prototype is designed for 10⁸ bits of storage but was populated with 128 chips for a 1.3 x 10⁷ bit capacity. Preliminary tests indicate satisfactory operation. Results of these tests are presented and variations with designed characteristics discussed.
    • Optical Fiber Thermosensor

      Ishikawa, S.; Doi, K.; Hamatsuki, T.; Nonaka, S.; Nippon Electric Co., Ltd. (International Foundation for Telemetering, 1978-11)
      An optical fiber thermosensor with bimetal has been newly developed for telemetering temperature readings at an electrically noisy place and high voltage point. Thermosensor measuring accuracy was less than 0.5 degree in the 10 to 50°C range. The device has proved to be practical and reliable.
    • 20/30 GHz Satellite Systems Technology Needs Assessment

      Stevens, Grady; Wright, David; National Aeronautics and Space Administration (International Foundation for Telemetering, 1978-11)
      NASA is involved in exploring the potential of the 20/30 GHz bands as evidenced by the propagation work in the ATS series by NASA-Goddard and, more recently, by the systems and market effort by NASA-Lewis. This paper focuses on the system and market work done by NASA-Lewis. Included are results of previous contractual and in-house studies, as well as preliminary results of on-going market and system studies. Baseline concepts for evaluating technology needs are also included.
    • TDRSS Multiple Access Receiving Phased Array System

      DuPree, J. E.; TRW Defense and Space Systems Group (International Foundation for Telemetering, 1978-11)
      A 30-element phased array, with remote beamforming and multiple access signal design, is the basis for a new multiple access concept to be used by the Tracking and Data Relay Satellite System (TDRSS). System tradeoffs evolved a control and calibration concept which parallels modern estimation theory in dynamic systems and reduces the complexity of adaptive control while maintaining the necessary accuracy. A system dynamic model propagates "open loop" estimates of optimal weight vectors based on user satellite ephemerides derived from tracking data. A sampled-data closed loop adaptive control system periodically updates the beam-steering vector to eliminate parameter drifts and modeling errors, and to maintain the weight vector near optimum. The concept is primarily useful in the specified noninterference environment, though some nulling capability is possible.