• THE FEDERAL DATA ENCRYPTION STANDARD IN THE 1980’S

      Burris, Harrison R.; NOETECHNIC INDUSTRIES INC. (International Foundation for Telemetering, 1981-10)
      The development of the federal data encryption standard is traced from the requirements leading to inception of the project through the publication of federal and commercial (ANSI) standards. The algorithm is briefly reviewed and strengths and weaknesses are discussed. Current applications are described and some potential developments are presented.
    • FREQUENCY HOPPING SYNTHESIZERS EMPLOYING CONVENTIONAL, COMMERCIALLY-AVAILABLE INTEGRATED CIRCUITS

      Dixon, R. C.; R & D Associates (International Foundation for Telemetering, 1981-10)
      A number of integrated circuit frequency synthesizers are available for use in commercially-oriented radio receivers and transmitters. Application of these for frequency hopping systems is extremely attractive, but little information exists as to their capability for such use. This paper examines the switching speed, frequency range, and flexibility of currently available I. C.’s, and gives both experimental and calculated results.
    • FREQUENCY SELECTIVE SURFACES FOR SPACEBORNE MISSIONS

      Herndon, D.H.; Herschelman, F.Q.; Harris Corporation (International Foundation for Telemetering, 1981-10)
      Periodic arrays of metallic scatters have found widespread application in microwave antennas as frequency selective surfaces. The exact surface reflection and transmission characteristics depend on the length, width, and spacing of the metallic elements, and the dielectric constant and thickness of the supporting structure. The arrays are effectively filters when used in this application, and it would seem more efficient to specify the response with poles. The poles of each array are calculated using the Singularity Expansion Method (SEM). How the poles vary with changing geometrical parameters are calculated and plotted. The currents, and charges induced on the scatterers are treated using Floquet theory which is incorporated in a vector E-field integral equation. The SEM parameters are presented in the form of appropriate graphs and tables. In addition these data are compared with previously obtained data for multiple bodies and in particular with data used in the design of the frequency selective surface for the GALILEO space mission.
    • FUTURE TRANSATLANTIC LIGHTWAVE COMMUNICATION SYSTEMS

      Wagner, Richard E.; Bell Laboratories; Runge, Peter K. (International Foundation for Telemetering, 1981-10)
      Bell Laboratories is actively involved in applied research work on single mode long wavelength technology which might lead to a development program for optical undersea transatlantic communication systems. This talk addresses the economic justification for optical transatlantic systems, and describes projected system parameters for a first system targeted for service in the year 1988. The current state of technology of major system elements is described, and projections are made for future generation optical undersea systems.
    • A GENERAL APPLICATION REAL TIME PROCESSING AND DISPLAY SYSTEM

      Schumacher, G. A.; Sangamo Weston, Inc.-Data Systems Division (International Foundation for Telemetering, 1981-10)
      A general purpose system for the processing and display of telemetry data is described. The system uses a DEC PDP-11 mini-computer as the system processor. Systems of this type implemented in the past generally had limited data processing capabilities due to high data rates and limited CPU power. The Real Time Data Monitor System (RTDMS) is designed to maximize the data processing capability by teaming the CPU with a pre-processor. A total hardware/ software system was designed which is structured around certain commonly required classes of data. The system minimizes the processor overhead associated with each class thereby freeing time for useful processing. A complete software system was implemented which takes full advantage of the RSX-11M multi-task operating system. Because of the substantial data base required to configure the system, particular attention was given to the operator interface. A set of programs were implemented which construct all data base files required using interactive menus. Operator input is minimized as well as the training time required to set-up the system.
    • GEOSTATIONARY OPERATIONAL ENVIRONMENTAL SATELLITE (GOES)

      Nakamura, Apryll M.; Mallette, Leo A.; Hughes Aircraft Company (International Foundation for Telemetering, 1981-10)
      The GOES satellites are multifunctional satellites whose primary function is to provide continuous measurements of the earth’s surface and atmosphere from two geostationary orbit locations: 75°W and 135°W. This objective is accomplished with the Visible infrared spin scan radiometer Atmospheric Sounder (VAS). The atmospheric sounder is a new feature which will add a third dimension to the photographs of the earth seen nightly by TV newscast viewers. The satellite also contains a Space Environment Monitor (SEM) which includes three instruments: a magnetometer, a solar X-ray sensor and an energetic particle sensor (EPS), which monitor solar flares and near earth space environment. The satellite contains a communications system which, in addition to transmitting VAS, SEM and housekeeping data to earth, provides relay capabilities for the stretched VAS and weather facsimile (WEFAX) data, as well as for the Data Collection Platform (DCP). A sketch of the satellite is given in Figure 1. The telemetry system encompasses two subsystems: RF communications and baseband assemblies. A general diagram of the telemetry system is shown in Figure 2. The telemetry system consists of two functional operations; real time telemetry data which is frequency modulated into IRIG 12 and IRIG B, and PCM data which is phase modulated. The baseband assemblies collect, format and modulate the data. The RF system sums the PCM and IRIG signals, phase modulates it onto both the CDA and STDN carriers, and transmits it to the ground stations. The following sections will describe in further detail the operation of the PCM and real time telemetry functions, and a description of the satellite RF communications system.
    • GOES COMMUNICATIONS SYSTEM

      Fermelia, L. R.; Hughes Aircraft Company (International Foundation for Telemetering, 1981-10)
    • HARDWARE/SOFTWARE ARCHITECTURE FOR A MICROPROCESSOR AIRBORNE TELEMETRY ENCODER

      Kellom, Arthur W.; Sandia National Laboratories (International Foundation for Telemetering, 1981-10)
      Successful programming of a microprocessor for airborne telemetry requires attention to proven programming techniques, as well as consideration of additional constraints that are required by the hardware involved. This paper describes a custom microprocessorcontrolled telemetry encoder developed by Sandia National Laboratories. The telemetry is used to encode and transmit data from warhead development and quality assurance tests. This paper briefly describes the encoder, discusses in some detail the structure of the software, and concludes with a mention of future telemetry development planned. The general principles of encoding are emphasized rather than an extensive discussion of software used in this system.
    • A HIGH RESOLUTION MBA FOR EHF COMMUNICATION SATELLITES

      Cummings, William C.; Ricardi, Leon J.; Schwab, Leonard M.; Massachusetts Institute of Technology (International Foundation for Telemetering, 1981-10)
      Communication satellites currently operate at frequencies lower than 15 GHz. Future satellite communication systems will operate in the EHF band between 17 and 47 GHz, in order to realize increased bandwidth and antenna discrimination. Increased discrimination can be obtained with electrically large aperture antennas consisting of filled, or thinned arrays, or a multiple-beam antenna (MBA) using millimeter-wave optics. This paper describes a contemporary MBA and beam-switching network system capable of achieving high resolution and significant operational flexibility. The antenna can simultaneously provide narrow beams and medium-size beams directed to any point on the earth’s disc as seen from a geosynchronous satellite.
    • A HIGH-PERFORMANCE ERROR CORRECTION SYSTEM FOR DIGITAL TAPE RECORDERS

      Kessler, W.D.; Stein, J.H.; Sangamo Weston, Inc. (International Foundation for Telemetering, 1981-10)
      An erasure type error correction system for parallel high density digital tape recorders is described. The system can correct for error bursts of any length occuring on either single tracks or any two tracks simultaneously. Calculations of theoretical performance are compared with measured performance and a figure of merit for error correction systems is used to compare typical systems.
    • HOW SMALL CAN AN ELECTRO-OPTICAL TRANSOCEANIC CABLE BE?

      Wilkins, George A.; Naval Ocean Systems Center Hawaii Laboratory (International Foundation for Telemetering, 1981-10)
      Design theory and analyses are presented for a transoceanic, electro-optical ( E-O), telemetry cable which---because its data, power and tensile functions can be separately optimized---has a very small diameter and transport volume. These reductions are achieved with no compromises of operational or material constraints on the telemetry system. For example, an ocean E-O cable which can directly support repeatered, multi-fiber telemetry between Japan and the United States will have a diameter less than 0.75 cm. Its transport volume will be barely 5% of that required for the smallest coaxial cable (SD List 1 with a 3.18-cm diameter) now being used in transoceanic communications. A cable design is demonstrated for a set of system parameters which define a 5550-kmlong “baseline” communications system. The study evaluates that system’s sensitivity to changes in such system parameters as length, repeater power and separation, water depth and safety factor, cable specific gravity, dielectric voltage stress, conductor conductivity, and the failure- or yield strains of loadbearing components. It is concluded that the cable should be relatively inexpensive. Its design can be tailored for specific applications with little change in manufacturing complexity or cost. The cost and risk of ocean deployment should be considerably reduced, since small ships can be loaded with ocean-crossing lengths of this miniature E-O cable.
    • HOW THE 1980’s LOOK FOR GODDARD SPACE FLIGHT CENTER’S SPACEFLIGHT TRACKING & DATA NETWORK

      SMOR, PAUL R. (International Foundation for Telemetering, 1981-10)
      The Spaceflight Tracking and Data Network (STDN), operated by NASA’s Goddard Space Flight Center, finds itself adapting to internal and external changes. Among these changes, now familiar to all of us, are higher data rates, shrinking budgets, and to some extent this nation’s relations with foreign governments. This paper strobes the STDN in a period of rapid evolution. This evolution embraces automation, consolidation, and the development of a space borne data relay network to replace terrestial stations. The STDN is only one of several worldwide data and communications networks. Perhaps others will tread similar paths.
    • HUMAN FACTORS IN TELEMETRY SYSTEM DEVELOPMENT

      Chafin, Roy L.; Jet Propulsion Laboratory (International Foundation for Telemetering, 1981-10)
      Telemetry systems are becoming increasingly sophisticated and complex. At the same time, economics is forcing the use of fewer and less technically skilled operators. This paper suggests including human factors in systems design to better match system characteristics with operator characteristics. It discusses why human factors should be included in system design. It defines and discusses human factors. Human factors specialists are the practitioners of the art and science of human factors design. The art is in the experience and insight of the human factors specialists, and the science is in his knowledge of the theoretical foundations of human factors. His knowledge and experience is applied to telemetry system design at several places in the design effort. Early in the requirements phase, human factors specialists identify the human factors issues and establish man-machine interaction philosophy and human factors design guidelines. During the design phase they assist the designers on the detailed design of the man-machine interface. After and even during the design phase, the human factors specialists evaluate the design with theoretical analysis. After delivery, they evaluate the system in its operating environment using real operators.
    • IMAGING TERMINAL GUIDANCE SEEKER

      Mohanty, N. C.; The Aerospace Corporation (International Foundation for Telemetering, 1981-10)
      A certain guidance seeker is designed to aim at the location of the most vulnerable point of a moving target. The seeker extracts an appropriate feature of the target and continuously tracks it using a tracking algorithm. The performance of the tracker was evaluated in terms of probability of acquisition and positional error. The algorithm was verified using a data base obtained from the flight of an A-7E aircraft. The cockpit of the aircraft was continuously identified by a rectangular gate as the seeker’s aimpoint.
    • IMPACT OF LSI ON CRYPTOGRAPHY

      Cohen, Ken; Western Digital Corporation (International Foundation for Telemetering, 1981-10)
      The existence of a cryptographic algorithm in LSU gives the system designer real choices for integrating cryptography into a product. This paper will explore some of the trade-offs in providing data communication security at different levels of the ISO model and their impact on security and the ability to communicate.
    • IMPACT OF MOLECULAR BEAM EPITAXY TECHNOLOGY ON SPREAD SPECTRUM SYSTEMS

      O’Clock, George D.; Erickson, L. Peter; Physical Electronics Division (International Foundation for Telemetering, 1981-10)
      The ultimate limitations in system performance capabilities are often due to constraints imposed by various device or chip fabrication processes. Recent advances in semiconductor processing technology have helped to lift some of the device performance barriers that have a negative impact on system performance. Molecular Beam Epitaxy is one particular technique that has the capability to fabricate a wide range of high performance semiconductor devices with high levels of reliability and yield. Molecular Beam Epitaxy (MBE) is an ultrahigh vacuum evaporation process for growing epitaxial films on various substrate materials. The basic constituents of the films are thermally evaporated and directed toward a heated substrate. The evaporated materials are deposited on the heated substrate surface forming a film. MBE offers the ability to maintain a higher level of precise control over material composition and film thickness required for semiconductor devices utilized in microwave and millimeter wave spread spectrum system applications.
    • THE IMPACT OF THE IEEE-488 CONCEPT ON MEASUREMENT PRODUCTIVITY

      Stanley, George C.; Hewlett-Packard Company (International Foundation for Telemetering, 1981-10)
      In the mid 1970’s three events came together that have had a major impact on measurement productivity. The most significant of these was the IEEE-488 Interface Bus. The second was the “friendly”, interpretive-language desktop computer and the third was the intelligent or “smart” instrument. Since the combined impact of these three has been enormous, their-development and relationships will be briefly traced. Next covered will be the technical characteristics of the interface bus with emphasis on what sets the technical limits of speed, distance, and number of products connected. Knowing this leads to a discussion of how to go beyond these limits if required. Finally, this paper examines the application of these concepts using two aerospace examples and describes the resultant productivity improvements.
    • THE INFLUENCE OF ARM FILTER DELAY ON TRACKING PERFORMANCE OF A COSTAS LOOP

      Holmes, Jack K.; Holmes Assoc. Inc. (International Foundation for Telemetering, 1981-10)
      It is demonstrated that the effect of the arm filters with NRZ data in a second-order Costas loop is to introduce delay in the loop which causes the tracking-error jitter to increase. It is shown that the tracking-error jitter becomes unbounded at exactly the same value of delay as the loop becomes unstable. The results are derived for both the one pole passive and the Integrate and Dump arm filter cases. A representative calculation shows that this is normally not a significant problem in properly designed loops.
    • INFORMATION RATES IN FIBEROPTIC LINKS WITH MULTI-LEVEL PULSE INTENSITY ENCODING (MPIM)

      Sorensen, A. N.; Gagliardi, R. M.; The Aerospace Corporation; University of Southern California (International Foundation for Telemetering, 1981-10)
    • Infrared telemetry range for fire management

      Warren, John R.; USDA Forest Service (International Foundation for Telemetering, 1981-10)
      The USDA Forest Service has used airborne infrared systems for forest fire detection and mapping for many years. The transfer of the images from plane to ground and the transposition of fire spots and perimeters to maps has been performed manually. A new system has been developed which uses digital image processing, transmission, and storage. Interactive graphics, high resolution color display, calculations, and computer model compatibility are featured in the system. Images are acquired by an IR line scanner and converted to 1024 x 1024 x 8 bit frames for transmission to the ground at a 1.544 M bit rate over a 14.7 GHZ carrier. Individual frames are received and stored, then transferred to a solid state memory to refresh the display at a conventional 30 frames per second rate. Line length and area calculations, false color assignment, X-Y scaling, and image enhancement are available. Fire spread can be calculated for display and fire perimeters plotted on maps. The performance requirements, basic system, and image processing will be described.