• DESIGN AND PERFORMANCE OF AN OPTIMAL RATIO COMBINER USING AGC AND AM WEIGHTING

      Lennox, William M.; Microdyne Corporation (International Foundation for Telemetering, 1981-10)
      The conventional AGC weighted diversity combiner design experiences performance problems in the presence of fast fade rates of amplitude and phase of RF input signals. These problems and other needs are discussed by the author in detail along with the design and theory of a new combiner that has been developed. It successfully overcomes these phase and amplitude fading problems and also addresses many other problems such as the need for wider bandwidths, computer control, and many other improvements. These improvements are necessary to increase the state-of-the-art in the telemetry and communications combiner. The design criteria and realization of the design goals are described in detail accompanied by a block diagram discussion of the theory of operation.
    • DESIGN AND PERFORMANCE OF AN UNDERSEA, SINGLE-FIBER MULTI-REPEATER, FULL DUPLEX, ELECTRO-OPTICAL DATA LINK

      Wilkins, G.; Nakagawa, A.; Kamikawa, N.; Baldwin, D.; Couch, P.; Naval Ocean Systems Center Hawaii Laboratory; ITT-EOPD (International Foundation for Telemetering, 1981-10)
      Fiber optics’ major contributions to undersea communications should include greater telemetry bandwidth, improved data precision and a decrease of system volume. The last two of these served as primary goals during recent design, fabrication and ocean testing of an undersea, electro-optical (E-O) telemetry system. The system’s total length was nearly 70 km. It contained 8 in-line repeaters which were powered through the E-O cable. Data were transmitted full duplex (22 MB/s at 0.83 μm & 43 KB/s at 1.06 μm through a single optical fiber. Power consumption was 1.69 watts for each repeater. Telemetry BER through the 70-km cable path was better than 10^-9 at 22 MB/s. The repeater housings were designed for 1-km ocean depths. Their dimensions (including bend-limiting cable terminations) were 2.88-cm diameter by 30.5 cm length. Each repeater contained special circuitry so that it would be queried from shore in a fault diagnosis mode. Designs and performance are reported for the E-O telemetry system and for its major components.
    • DESIGN FEATURES OF A NEW REMOTE CONTROLLED TELEMETRY RECEIVER

      Knowles, Robert C.; Moore, John M.; Woodworth, Donald J.; Magin, Greg A.; Microdyne Corporation (International Foundation for Telemetering, 1981-10)
      This paper describes some design features of a new microprocessor controlled, single channel telemetry receiver which will have use in the automated telemetry systems beginning to emerge. The parameters controlled, and the methods used to interface the receiver with the controller or another slave receiver to create the equivalent of a dual channel remote controlled receiver are discussed. A general description of the software utilized by the receiver is included. A new four bandwidth FM demodulator is described which utilizes modern technology to provide FM demodulation over the full range of receiver IF bandwidths. It features a high gain limiter having excellent output waveform symmetry and a linear phase detector with PIN diode switched linear phase shift networks to realize a demodulator exhibiting excellent linearity. A wide angle PM demodulator is also described which features a novel antisideband circuit utilizing PM feedback to essentially unmodulate the received signal and thereby prevent sideband lock.
    • DEVELOPMENT OF A MILITARY COMMUNICATION SYSTEM: A MULTIPLE RATE PROCESSING APPROACH

      Kline, E. Lee; Naval Research Laboratory (International Foundation for Telemetering, 1981-10)
      This paper represents some considerations resulting from work conducted during a Navy study of secure voice system alternatives and the development of military communication systems. It begins by identifying a set of attributes for a “goal” military communication system. The paper then presents a realizable communication system concept which could be used as a basis for a future system design. The concept is based on an embedded multiple rate system where a basic mode, supported at the lowest transmission rate, is enhanced using additional transmission capacity, when it is available, to support a higher rate. The conclusion discusses the impact of this concept on some of the functions a military communication system must perform.
    • DIDON: DIGITAL DATA IN VIDEO

      BERNHEIM, J.-P.; Communications Enaineer (International Foundation for Telemetering, 1981-10)
    • DIGITAL DATA IN VIDEO PROCESSING SYSTEMS

      Morse, Bob A.; BELL TECHNICIAL OPERATIONS (International Foundation for Telemetering, 1981-10)
      Digital information in video systems is an expanding field. The use of digital video equipment is continuously being examined and updated at USAYPG. There are fully operational systems currently being used by BELL TECH. OPS at the proving ground. I shall cover some of the uses and capability of the systems as well as the individual pieces of equipment in the systems
    • DISPLAY, ANALYSIS AND DISSEMINATION OF METEOROLOGICAL INFORMATION

      Baker, Neal K.; The Aerospace Corporation (International Foundation for Telemetering, 1981-10)
      Meteorological forecasting is a combination of art and science. The need for the human intelligence process still remains. Computers have revolutioned the science of meteorology, but many forecasting tasks still require a large amount of human interpretation and interaction. The forecaster needs to have rapid access to information in order to verify, review, modify, and interpret the computer results. Currently the forecasters review the various data types separately. The system under development will synthesize and display to the forecaster satellite imagery, graphical overlays of the meteorological fields, and alphanumeric reports in a timely manner. A local network will place the forecaster directly on an electronic network which spans the world. Additional tools are provided to the forecaster, such as animation and pseudo-color, to enhance the human recognition processes. Multiple level zooms are utilized to span the range from global to mesoscale phenomena. The forecaster then draws in the human interpreted details. The system merges the human input and adds the computer generated portions. The combined forecast information is disseminated to the weather central and field users. The system will reduce the product generation time by fifty percent. In. addition, special products can be rapidly made up and sent to the users.
    • DISTORTION CONTROL IN ONBOARD PROCESSOR DESIGN

      Lytle, A. C.; The Aerospace Corporation (International Foundation for Telemetering, 1981-10)
      Attention is focused on distortion as an obstacle in achieving design performance goals of onboard processors used in satellite signalling systems. Despreader signal processing loss is expressed analytically as a function of the end-to-end passband differential phase distortion characteristic. Distortion sources are identified and examined for the type and amount of performance degradation. Coping methods are presented. Typical loss values are given graphically for standard reference purposes.
    • DIVERSITY TECHNIQUES FOR OMNIDIRECTIONAL TELEMETRY COVERAGE OF THE HiMAT RESEARCH VEHICLE

      Harney, Paul F.; NASA Dryden Flight Research Center (International Foundation for Telemetering, 1981-10)
      The control system for the highly maneuverable aircraft technology (HiMAT) remotely piloted research vehicle uses airborne and ground-based computers that communicate via uplink and downlink telemetry. It is imperative for this communication to be uninterrupted. Since antenna radiation patterns are normally less than ideal for continuous reception or transmission at all aircraft attitudes, a frequency diversity concept and an antenna diversity concept were developed, implemented, and tested on the HiMAT vehicle. This paper describes the system and the results of the flight tests.
    • DMSP PRIMARY SENSOR DATA ACQUISITION

      Lieske, Roger W.; Westinghouse Aerospace Divisions (International Foundation for Telemetering, 1981-10)
      A Data acquisition system which provides global pictorial cloud cover data for operational military meteorological purposes is described with emphasis on significant design features. These features include near constant geometric resolution through use of an oscillating scanner and variable instantaneous field of view (IFOV), thermal infrared channel output linear with temperature, visible wavelength sensitivity continuous from sub-solar to sublunar, along scan gain control permitting albedo images through the terminator, glare suppression enabling sensing of nighttime scenes in the presence of solar illumination on the spacecraft, wow/flutter correction of video data sampling to that of a reference scan motion, and dual geometric resolution capability from a single detector by synthesis of low resolution data.
    • DoD SATELLITE COMMAND AND CONTROL NETWORK

      Rugg, Charles J.; The Aerospace Corporation (International Foundation for Telemetering, 1981-10)
      Consideration of the command and control of the United States military satellites precipitated a review of the existing satellite control networks. This review cataloged the existing facilities and highlighted their differences and commonalities. Areas that have promise for providing mutual backup and interoperability are noted. A long-range goal is to achieve a degree of interoperability such that command and control of any particular satellite system can be supported by any of several ground control systems.
    • DOMSAT OPERATIONS SUPPORT WITH A SINGLE COMPUTER

      Ekman, Donald E.; Hanson, Charles W.; Ford Aerospace & Communications Corporation (International Foundation for Telemetering, 1981-10)
      The use of a single mini-computer for total operations support of a domestic communications satellite offers several advantages. This paper describes the computer hardware and software configuration of a ground complex that is both a control center and a TT&C station. A single computer (with a totally redundant backup) serves both the needs for realtime TT&C functions as well as such offline functions as orbital analysis, mission planning and satellite performance evaluation. Although telemetry data processing and analysis is a significant part of the computer load, other tasks involved in operational support and planning are described in order to define the scope of the total operations support problem and the way it was solved in the single computer configuration.
    • DSCS-III ATTITUDE CONTROL SYSTEM

      Bonello, D.; Basuthakur, S.; Valley Forge Space Center (International Foundation for Telemetering, 1981-10)
      The DSCS-III (Defense Satellite Communications System) Spacecraft was designed and built for the Air Force Space Division by General Electric Space Division in Valley Forge, PA. Development of this satellite started in 1978 and was culminated in the recent (May 81) completion of testing of the first flight unit. The attitude control system for this synchronous orbit spacecraft is a three-axis zero momentum, general microprocessor controlled concept that not only provides attitude and velocity control during the normal seven year orbital life, but also provides provisions to operate and maintain control during special circumstances such as failed battery eclipses, lunar eclipses, and nuclear events. In addition, the attitude control system electronics and embedded software system provides the capability to drive the single axis solar array, two axis gimbal dish antenna, and translates ground commands into beam pattern reconfiguration driver signals for the phase shifters and variable power dividers of the payload multiple beam antennas. The control system equipment compliment consists of a redundant passive radiation balance earth sensor, solar array yoke mounted analog sun sensors, and a yaw rate gyro as the sensing elements, the aforementioned general purpose microprocessor (Attitude Control Electronics containing 8K of PROM memory and 1K of RAM in which is implemented the control logic and algorithms, four skewed reaction wheels for normal orbital control torquing/momentum storage and 16 one-pound hydrazine thrusters for initial acquisition and orbit adjust maneuvers and wheel unloading. The basic requirements to which this system was designed are to (i) acquire an earth pointing reference from arbitrary initial attitudes and rates of 1.1°/sec per axis, maintain control during initial inclination error removal (maximum of 2. 5 degrees) to within 1, 1 and 2 degrees for the roll, pitch, and yaw axes respectively for all times of year and orbit positions, (ii) maintain pitch, roll, and yaw errors to less than 0.08, 0.08, and 0.8 degrees during normal orbital operations (iii) maintain orientation of the solar array to within 1° of the sunline, (iv) establish and control station latitude and longitude to within + 0.1°, (v) provide the capability to recover from the effects of a nuclear event via autonomous detection and corrective action, (vi) provide the capability to reorient/reconfigure the payloac gimballed dish antenna and multiple beam antennas and (vii) provide the capability to modify up to 1K of the PROM stored software using a ground commanded mode. This DSCS-III ACS as designed and tested meets all of its requirements with a system weighting only 83. 3 pounds and using approximately 64 watts of power.
    • DUAL FREQUENCY BAND OPERATION OF TE/TM12 MULTIMODE HORNS

      HOWER, R. THOMAS; HARRIS CORPORATION (International Foundation for Telemetering, 1981-10)
      Multimode rectangular horn radiators have been in widespread use as reflector antenna feed elements for many years. These horns provide equal E and H planes over moderate bandwidths. With a few simple additional design considerations, however, these same horns can operate over two separate frequency bands. Dual mode operation is achieved by designing to prohibit generation of higher order beamshaping modes for lower operating band. Thus the horn operates as a square pyramidal horn at the low band and as a traditional multimode horn in the upper band. Upper band performance is not affected; however, efficiency in the lower band is somewhat less due to unequal beamshapes characteristic of square pyramidal horns. A horn utilizing these design concepts was developed and tested. Resultant horn geometry, corresponding reflector antenna aperture efficiencies and beamshapes at both bands are presented.
    • EARTH STATION IMPLEMENTATION IN THE CANADIAN DOMESTIC SATELLITE SYSTEM

      Winter, A.E.; Nicholson, C.C.; Telesat Canada (International Foundation for Telemetering, 1981-10)
      The domestic communications satellite system operated by Telesat Canada has expanded significantly since its inception in 1973, when, using the Anik A series of satellites in the 6/4 GHz bands, 34 stations commenced service. Since that time, Telesat Canada has implemented many earth stations operating in the 6/4 GHz and 14/12 GHz bands. The paper reviews the design and performance features of the earth stations which provide the wide variety of Telesat services, from “Thin Route” stations used in the Canadian North to the “Network Television” stations used in more southern locations. As an example, the 14/12 GHz heavy-route stations, providing long-haul digital and video uplinks between major city downtown locations, are described in more detail. In conclusion, a summary of new directions in satellite earth station design is presented, including single-circuit transportable earth stations for exploration companies and light-route TDMA earth stations for advanced business networks.
    • EFFECTS OF SOLAR CELL IMPROVEMENTS ON SATELLITE DESIGN

      Wolff, George; Ellion, M. Edmund; Hughes Aircraft Company (International Foundation for Telemetering, 1981-10)
      Recent advancements in gallium arsenide (GaAs) solar cell technology have resulted in appreciable improvements in solar panel performance. The effects of these improvements on weight, size, and power are discussed for three typical satellites: a spin stabilized satellite with rigid drum panels, a 3-axis stabilized satellite with rigid fold-out arrays, and a 3-axis satellite with flexible roll-out arrays. The satellites chosen for these examples are the Hughes HS 376 series standard commercial spin-stabilized satellite, the NASA Solar Max Mission Satellite, and the NASA Large Space Telescope Satellite. The discussion also includes the effects of radiation at synchronous orbits compared to low earth orbits and the effects of temperature on the performance of the solar panel. Typical advantages of a GaAs solar cell spinning array having a beginning of life (BOL) 1 kW power level, in synchronous orbit, over the most efficient silicon solar panels are a reduction of 27 percent in area and a reduction of 7 percent in weight. The improvements are even more dramatic for higher temperatures as will be discussed in the text of this paper. These GaAs solar cells are expected to be available in production quantities by 1985 at a price close to that of silicon cells.
    • END COUPLED PARASITIC MICROSTRIP ANTENNA

      KALOI, MO; PACIFIC MISSILE TEST CENTER (International Foundation for Telemetering, 1981-10)
      A Parasitic Microstrip Antenna Array is discussed. The array consists of different lengths of microstrip radiating elements spaced apart in an end-to-end arrangement. Only one element is actively fed at its feedpoint, and energy emanating from the fed element is primarily coupled to parasitic elements by the electric field generated in the fed element. The radiating pattern is determined by the phase relationship and amplitude distribution between the excited fed element and the parasitic elements. This antenna configuration exhibits higher end fire gain along the missile axis than obtained with arrays having elements individually fed.
    • ENHANCEMENT OF ENDURABILITY BY MODERN TECHNOLOGY IN TRANSPORTABLE MILITARY TT&C GROUND TERMINALS

      Cuccia, C. Louis; Winslow, Roger G.; Ford Aerospace & Communications Corporation (International Foundation for Telemetering, 1981-10)
    • EVOLUTION OF TELEMETRY AND COMMAND SYSTEMS FROM EARLY BIRD TO INTELSAT V

      Magnusson, S. Erland; International Telecommunications Satellite Organization (International Foundation for Telemetering, 1981-10)
      The telemetry and command system on INTELSAT satellites has gone through an evolution from the early series of satellites where simplicity and satellite reliability was emphasized to the latest series of satellites where communications systems reliability is emphasized. The early telemetry and command systems were integrated with the communications subsystem on the satellite and had some redundancy. Later systems are autonomous with complete redundancy and cross-strapping between the systems to a large extent.
    • EXPERIMENTAL COMPARISON OF PCM/FM, PCM/PM and PSK

      Law, Eugene L.; Pacific Missile Test Center (International Foundation for Telemetering, 1981-10)
      This paper compares the experimental bit error rate (BER) performance of PCM/FM, PCM/PM, and PSK. The data are presented as BERs versus signal-to-noise ratio (SNR) in a bandwidth equal to the bit rate. The effects of premodulation filtering and receiver IF bandwidth are discussed. The necessary RF bandwidths for these modulation methods are also discussed. Two methods of generating PSK signals were used: ±90E linear phase modulation and mulitplication of the RF carrier by ±1 using a double balanced mixer. The first method will be referred to as PCM/PM (±90E) in this paper.