• GDSC Aerospace Test System (ATS)

      Layton, J.; Schiano, C.; Grumman Data Systems Corp. (International Foundation for Telemetering, 1978-11)
      Grumman Data Systems Corporation (GDSC) is presently developing another in a series of computerized realtime systems which accepts, preprocesses, analyzes and displays telemetry and range data. This new Aerospace Test System (ATS) will first be utilized by the Navy at the Pacific Missile Test Center (PMTC). The computerized test system will analyze data, in realtime, being telemetered from missiles, aircrafts and satellities. The system will accept, decommutate/demodulate, preprocess, analyze and display data being transmitted in the forms of PCM, PDM, PAM, and FM. The system will allow test personnel to continually monitor, in realtime, critical raw and calculated parameters. The answers provided to test personnel, in one phase of the mission, will give them the ability to proceed into the next with a high degree of confidence. The vast amounts of data acceptable by the system, together with its analytical and display capabilities will allow test personnel to accomplish several tests during a single time frame. The system will also allow test personnel to be in complete control of their mission via the data uplink capability. It is a system that support Batch, Time Share, and Remote job entry processing concurrently. Utilized properly, it can greatly reduce the quantity and increase the quality of batch processing.
    • 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 Geometric Moment Bounding Algorithm

      King, Maurice A., Jr.; The Aerospace Corporation (International Foundation for Telemetering, 1978-11)
      There are many important problems in the field of communications theory whose solution is the expectation of a function of a random variable. Examples include linear interference problems such as intersymbol interference and co-channel interference. In these cases, it is often not computationally feasible to evaluate the expectation exactly. This paper presents an algorithm that will compute tight upper and lower bounds to generalized moments of a broad class of random variables. The procedure is based on an isomorphism theorem from Game Theory. The technique is easily understood while yielding excellent results for this class of communication problems.
    • Gigabit Detectors for Visible Space Laser Communications

      Green, Samuel I.; McDonnell Douglas Astronautics Company (International Foundation for Telemetering, 1978-11)
      Performance data taken on several candidate high data rate laser communications photodetectors are presented. Measurements of bit error rate versus signal level were made in a 532 nm system at 500 Mbps.
    • GPS Overview and User Equipment Antijam Design

      Hemesath, Norbert B.; Hutchinson, William M.; Rockwell International (International Foundation for Telemetering, 1978-11)
      The Global Positioning System (GPS) features an all-weather global coverage navigation sensor with 0.01-nmi positioning accuracy. In the following paper, GPS is described with emphasis on antijam considerations developed in the USAF AFAL Generalized Development Model, GDM. Section 1 provides an overview of the GPS ground, space, and user segments. Section 2 describes antijam issues and techniques applicable to GPS. Section 3 describes the GDM design with emphasis on antijam. features. The objectives of the paper are thereby threefold. The first is to give an overview of GPS, how it works, its participants, and its status. The second is to provide a tutorial discussion of spread spectrum receiver design related to GPS (some knowledge of signal processing principles is therein assumed). The third is to provide an example of GPS receiver design which incorporates antijam features.
    • The GPS Satellite and Payload

      Codik, Andrew; Gronlund, Robert A.; Rockwell International Corporation (International Foundation for Telemetering, 1978-11)
      The NAVSTAR/Global Positioning System Satellite is briefly outlined as is the technique for navigation using signals from such satellites. A description of the GPS navigation subsystem with emphasis on its microprocessor and its interfaces and software routines is given.
    • GPS User Equipment, A Concept in Modular Design

      Candy, Donald W.; Hoover, Wayne M.; Texas Instrument Incorporated (International Foundation for Telemetering, 1978-11)
      A brief introduction to the Global Positioning System is presented. Functional modularity of GPS User Equipment systems and subsystems is studied. Physical modularity and commonality of hardware and software functions are discussed with respect to Design To Cost (DTC) and Life Cycle Cost (LCC) goals. Commonality of hardware and software support systems is explored with respect to increased development efficiency. Finally, a composite overview of the Texas Instruments High Dynamics and Manpack Vehicular User Equipments is presented with emphasis placed on the use of technology and vertical integration for DTC/LCC.
    • A Hardware Comparison of Intermicroprocessor Communications Techniques

      Korgel, C.; Lohaus, T.; Pape, D.; Martin Marietta Corporation (International Foundation for Telemetering, 1978-11)
      A generalized multimicroprocessor utilizing the TI9900 and AMD2901 microprocessors is presented. Different types of microprocessors are used to provide extensive computational capability, versatile interprocessor communications, high reliability, and system flexibility. The system is especially suitable for high speed signal processing, data processing, and data handling. Measured data on the speed of interprocessor communication for three techniques is presented along with a comparative assessment of flexibility and reliability for the techniques.
    • High Density 42-Track Magnetic Tape System

      Montgomery, J. H.; Martin Marietta Corporation (International Foundation for Telemetering, 1978-11)
      Design and development of a 42-track high density magnetic tape system for the NASA SEASAT program is described. Both record and playback at a nominal 120 megabits per second from a single data stream was achieved on a 1-inch mylar tape with bit error rate better than 1 x 10⁻⁶ without error correction. Solutions are presented to the requirements of data encoding, high bit rates, recovery from tape dropouts, and efficient use of tracks. This now operational system features a Channel Performance Status Panel, a Tape Bypass Mode, and a MUX/DEMUX unit capable of operating at 150 megabits per second.
    • High Linear Density Recording Study

      Levy, Avner; Bell & Howell (International Foundation for Telemetering, 1978-11)
      A series of tests were conducted in an attempt to study the recording behavior of Enhanced Nonreturn to Zero (ENRZ) code at high linear recording densities. Using the "eye" pattern as a criteria in the first phase, the tests clearly demonstrate the sensitivity of a tape recorder to the DM (Delayed Modulation) coding technique as compared to ENRZ. For the same linear density, ENRZ has a considerably wider margin than the DM code. In the second phase of that study, a series of tests were conducted using high energy tape and magnetic heads with reproduce gaps in the order of 12 μin, referred to as "double bandwidth heads." Using present day technology, it was possible to demonstrate linear packing density never before achieved on magnetic recording tape.
    • High Performance Circulators, Isolators and Electronic Waveguide Switches

      Piotrowski, Wieslaw S.; TRW Defense and Space Systems Group (International Foundation for Telemetering, 1978-11)
      This paper presents the results of a most recent high technology development program that has led to significant state-of-the-art advances in the design and development of circulators, isolators and electronic waveguide switches at microwave and millimeter wave frequencies. These components are constructed by the use of an analytical design procedure. They are characterized by excellent electrical and environmental performance and feature a simple mechanical configuration, which results in significantly reduced prices. These units are presently commercially available from Aertech Industries, Sunnyvale, California, a TRW subsidiary.
    • High Speed A/D Converter Technology Survey

      Hobrock, L. W.; TRW Systems (International Foundation for Telemetering, 1978-11)
      Surveyed are current and future high speed A/D technologies with potential for a significant impact on future systems. Current bipolar silicon monolithic quantizers and hybrid sample-and-hold circuits are described. The gallium arsenide integrated circuit technology, including FETs and TEDs, provides speed increases from 10 to 100. Josephson Junction devices are discussed as a technology potentially offering radical increases in sample rates and reductions in power.
    • A Hybrid Data Compression Algorithm for Image Telemetry

      McCaughey, Dennis G.; University of Arizona (International Foundation for Telemetering, 1978-11)
      This paper presents an image coding algorithm using spline functions that is competitive with the more conventional orthogonal transform methods at data rates of 1 bit/pixel or less. Spline coding has the added attraction of an optical implementation arising from the fact that least squares image approximations also produces least squares approximations to the image derivatives. A first order spline is used to approximate the proper order derivative of the image whose order is determined by an analysis presented in the paper. The image derivative is then encoded and transmitted to the user who reconstructs the image by a k-1 order integration which can be done optically.
    • Hybrid Packet and Circuit Data Networks: Design and Operation Issues

      Gerla, Mario; University of California, Los Angeles (International Foundation for Telemetering, 1978-11)
      Experience with packet switching during the past decade has shown that the packet technology is very cost effective for bursty communications between computers and terminals. However, for applications characterized by a steady instead of bursty flow of information (e.g., file transfer, digitized speech, facsimile), it has been established that pure packet protocols are often inadequate because of the unnecessarily high line overhead and the high delay fluctuations between consecutive packets [1]. For such applications, a circuit switching approach (either physical or virtual) appears more advantageous [1],[2]. In the physical circuit approach, bandwidth is dedicated to a connection for the entire duration of the session; while in the virtual circuit approach the path is fixed at the beginning of the session and some expected bandwidth is guaranteed, in a statistical sense, along the path (but no physical bandwidth is assigned).
    • Image Quality Considerations of Compressed Video Imagery

      Pearson, J. J.; Millman, M. W.; Maitra, S.; Lockheed Palo Alto Research Laboratory (International Foundation for Telemetering, 1978-11)
      Most work to date on image data compression has been based on single static images and the use of mean square error (MSE) as an objective quality criterion. However, many current requirements for video bandwidth compression, such as Remotely Piloted Vehicle and "smart" ordnance video links, include dynamic (moving) scenery and severe channel noise. The image degradation effects of the bandwidth compression technique will then fall into three categories: Degradation of a static image; effects due to any frame segmenting and partial frame transmission used; and the impact of uncorrected channel errors. In this environment, the more powerful, but also more complex techniques, i.e., the various transform techniques, may provide less acceptable imagery than simple techniques (such as DPCM or Lockheed's CAQ algorithm) since their complexity may require frame slicing, i.e., the compression and transmission of only a segment of a frame during each frame period. Also, the one-dimensional techniques often prove more effective than twodimensional techniques because the vertical redundancy they retain can be used to eliminate uncorrected errors. The MSE criterion for image quality, known to be crude and often misleading in static images, is totally inadequate to quantify the impact of scene dynamics and uncorrected channel errors.
    • The Impact of LSI on Telemetry Systems

      Finn, W. J.; Karwoski, R. J.; TRW LSI Products (International Foundation for Telemetering, 1978-11)
      Any system which measures, transmits over a distance, receives, and processes signals can be defined as a telemetry system. Video transmission systems, satellite communications systems wideband data links, and TDM/FDM transmultiplexers all have one thing in common: an increasing need for high-speed digital signal processing. This paper is intended to serve as an introduction to the application of LSI to telemetric signal processors.
    • Impact of Microcomputers on Telemetry and Telecommunications

      King, J. B.; Flight Systems, Inc. (International Foundation for Telemetering, 1978-11)
      The next computer revolution is under way. The first computer revolution impacted government and big business; the current revolution is affecting small businesses, schools and homes. The demands that will be placed on the telemetry and telecommunications industry in the next decade are mind-boggling. New products, new techniques and new jobs must be developed to respond to that demand. This paper presents future applications of microcomputers in communications and what that portends for our society.
    • 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.
    • Interleaving of Reed-Solomon Viterbi Concatenated Coding Channel

      Chu, Cecelia; Miller, Warner H.; Goddard Space Flight Center (International Foundation for Telemetering, 1978-11)
      In this paper, two interleaving schemes are discussed and several R-S code array synchronization configurations are investigated. A procedure for obtaining synchronization sequences, for the R-S code array, under specified conditions is suggested and it is followed by the identification of sequences with desirable properties. Several graphs are presented, e.g., false synchronization probability versus various bit error rates for the number of errors permitted, and also, the missed synchronization probability versus various bit error rates for number of errors permitted and for various lengths of synchronization sequences. For the interleaving schemes discussed there is no analytical advantage, with respect to array synchronization, for selecting one scheme over the other.
    • International Telemetering Conference Proceedings, Volume 14 (1978)

      International Foundation for Telemetering, 1978-11