• VARIABLE DATA BIT RATES WITH A FIXED HOP RATE NONCOHERENT FH/MFSK SYSTEM

      Omura, Jim K.; School of Engineering and Applied Science Los Angeles (International Foundation for Telemetering, 1981-10)
    • ADVANCED 14/12 AND 30/20 GHz MULTIPLE BEAM ANTENNA TECHNOLOGY FOR COMMUNICATIONS SATELLITES

      Chen, C.C.; TRW Defense and Space Systems Group (International Foundation for Telemetering, 1981-10)
      This paper discusses recent TRW advances in communications satellite antenna technologies for the 14/12 and 30/20 GHz bands. The 14/12 GHz antenna system provides 15 or more high gain, low sidelobe spot beams for contiguous coverage of the CONUS for point-to-point communications, or four contoured time zone beams for direct broadcast service. A 2-meter offset reflector has been built and tested to demonstrate the frequency reuse and beam isolation capabilities of the antenna. The 30/20 GHz antenna system provides 10 to 20 fixed beams for large volume traffic trunking service and six independently scanned beams for customer-premise-service within the CONUS. A proofof- concept model antenna for proving the technology feasibility is currently under development.
    • SYSTEM ASPECTS OF SCANNING BEAMS FOR WIDELY DISTRIBUTED USERS

      Kolba, Dean P.; M.I.T. Lincoln Laboratory (International Foundation for Telemetering, 1981-10)
      Satellite communications in the allocated EHF bands, (i.e., several frequency segments from ~20 GHz to 50 GHz) has the potential for providing interference resistant communications to users employing small, mobile terminals. To realize this potential, advanced spacecraft technologies are required, such as uplink coverage through high gain directive beams, onboard signal processing, and downlink beam hopping. Simultaneous worldwide uplink coverage could be obtained via many narrow uplink antenna beams which collectively cover the earth field-of-view. When worldwide communications traffic is low volume, a reduction in space segment impact can be achieved by using a few narrow uplink antenna beams to provide the required service. To minimize delays, these beams must be able to rapidly point anywhere within the field-ofview to cover individual users who require a channel for brief communications. The agile antenna beams can be shared through demand assignment techniques. A multimode common transmission format can provide both data and control channels. The data channels are available at several rates to allow either full duty cycle data transmission or burst data transmission. With burst transmissions, a single beam can support multiple calls in a time division multiplexed fashion. The control channels are utilized in coordinating the use of satellite resources to efficiently meet the communications needs of the users. This paper discusses the use of EHF satellite communicatons to provide service to widely scattered users. The use of control channels to request and coordinate service is described. Example control protocols are presented, and system performance is indicated.
    • NETWORK SUPPORT OF TDRSS

      Smith, Cassius C.; TRW White Sands Ground Terminal (International Foundation for Telemetering, 1981-10)
      The Tracking and Data Relay Satellite System (TDRSS) is controlled by a local computer network of nine Digital PDP-11/70s and a Univac 1100/82. Distributed processing of specific software tasks provides for high-speed response to time critical loop support, as well as increased reliability and flexibility of the overall system. Man-machine interface, spacecraft monitor/control and computer failover is supported by the distribution of tasks to specific computers within the network. Altogether, the network support of TDRSS makes possible tremendous increases in capability over conventional satellite ground stations.
    • VIDEO BASED INSTRUMENTATION SYSTEMS AND TECHNIQUES FOR MERGING DATA INTO VIDEO

      Keller, P.; Naval Weapon Center (International Foundation for Telemetering, 1981-10)
      A need is shown for the development of standardization in data into video encoders and decoders for instrumentation systems. Features such a standardized system should have are listed and discussed based on the authors experience with video instrumentation systems at the Naval Weapons Center and as a consultant.
    • SOFTWARE IN DRONE CONTROL

      Shaver, Robert L.; Sandia National Laboratories (International Foundation for Telemetering, 1981-10)
      High performance multi-use drones require complex control capability. Distributing the communications, control and navigation functions among different microprocessor systems connected in a network improves performance and reliability. Assembly language provides the means of optimizing time critical functions of communications and I/O control, which high level languages, such as PASCAL, ease development of mission management requirements. The use of real-time operating systems (RTOS) permits co-processing of a variety of functions in overall drone operation management. The RTOS is a software “bus” providing communications network for modules. Functions and modules are assigned priorities, enabled or suspended as needed to perform mission operational requirements via the RTOS.
    • NATO TEST AND EVALUATION RANGE STAVANGER, NORWAY

      Dahl, Ernest A.; NATO PUTTS System (International Foundation for Telemetering, 1981-10)
      The NATO Test Range at Stavanger, Norway permits cold environment testing of NATO Systems, common TLM data processing for many types of missiles, with both ship/shore control as well as evaluation. Figure 1 shows the location.
    • SPACE RADIATION HARDENING AND VLSIC TECHNOLOGY

      Josephson, Vernal; The Aerospace Corporation (International Foundation for Telemetering, 1981-10)
      Military Space Systems are required to have a certain level of immunity to all possible space radiation effects experiences during mission life time. These include upset and latchup from weapon x-ray bursts and cosmic rays, photo current burn-out of active junctions by large prompt doses of radiation, and performance degradation from accumulated dose due to enhanced radiation belts. Procuring piece parts capable of performing mission requirements and providing the desired immunity to these effects, and testing to verify the desired satellite immunity presents problems which must be considered when contemplating massive use of VLSIC technology where even higher desired levels of immunity may be desired. The techniques used for hardening and the testing required for hardness assurance will be discussed with emphasis on their application to VLSIC technology and its potential in space applications. An overall satellite was subjected to irradiation in order to verify its immunity to space radiation. These results will be discussed below.
    • THE BANDWIDTH OF SPREAD SPECTRUM SIGNALS

      Amoroso, Frank; Hughes Aircraft Company (International Foundation for Telemetering, 1981-10)
      Although spread spectrum systems depend on large bandwidth to achieve performance, they must also operate within bandwidth constraints imposed by frequency allocations. The measures of bandwidth relevant to performance are usually quite different from those defined in frequency allocations. In this paper a number of definitions of bandwidth are discussed, and a number of direct sequence pseudonoise (DSPN) modulation techniques are evaluated according to those definitions of bandwidth. A wide range of bandwidths per chip rate result, and trades among the modulation types are given.
    • LINE OF SIGHT COMMUNICATIONS TRENDS

      Sauer, Wes; Naval Ocean Systems Center (International Foundation for Telemetering, 1981-10)
      This paper briefly reviews some of the historical trends in LOS communications along with a synopsis of some of the characteristics associated with LOS systems. The Joint Tactical Information Distribution System (JTIDS) is briefly described as one example of current developments aimed at satisfying a number of requirements such as jam resistance, security, and error-free transmission. A brief review of the problems in various applications of LOS systems concludes the paper.
    • 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.
    • NAVY SATELLITE COMMUNICATIONS

      Captain Newell, John W.; Naval Electronic Systems Command (International Foundation for Telemetering, 1981-10)
      The significant advantages of quality and capacity, offered by Satellite Communications are now fully recognized throughout the Navy and DOD. Efficient use of the vital UHF SATCOM links is evolving as challenging command and control requirements are being met through micro-processor based system engineering. Extension of Navy SATCOM developments into the SHF and EHF portion of the spectrum offers further advanced capabilities to meet increasing tactical and strategic C³ requirements including anti-jam and LPI wartime capabilities. This paper reviews the several Navy SATCOM programs in being and in development to provide space age improvements in communications for the Fleet.
    • 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)
    • THE SBS TT&C SYSTEM

      Gordon, Marc D.; Bleiweis, John; Satellite Business Systems; COMSAT General Corporation (International Foundation for Telemetering, 1981-10)
      The SBS Telemetry, Tracking and Command (TT&C) System consists of one earth station in Castle Rock, Colorado and a combined earth station and control center in Clarksburg, Maryland. The system commenced operation with the launch of the SBS-1 spacecraft in November 1980, two and one-half years after the initiation of the design study. The system design utilized as a base the experience of COMSAT and SBS personnel on the INTELSAT and COMSAT General networks. From this base, a system was designed around real-time telemetry processing for four spacecraft that included such features as: subsystem oriented spacecraft displays, centralized control over the hardware and software at both sites, human factors orientation and ease of future expansion. The major functions performed include: spacecraft commanding, ranging, orbit and attitude determination, telemetry retrieval and analysis and comprehensive monitoring and alarm system.
    • 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.
    • 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.
    • SOLID STATE WIDEBAND POWER AMPLIFIER DEVELOPMENT AT 20 AND 44 GHz

      Ngan, Y.C.; Sun, C.; TRW (International Foundation for Telemetering, 1981-10)
      Two amplifier developments centered at 20 GHz based on GaAs IMPATT diodes will be discussed. The on-going developments of a 20 GHz communication amplifier sponsored by NASA Lewis using injection locking and resonant cavity combiner will be reviewed. A wideband 20 GHz amplifier to achieve 20 Watt 1 GHz bandwidth based on 3-dB hybrid couplers and stable mode of amplification, along with the results obtained from the constant voltage mode of amplification will be discussed. A wideband solid state amplifier designed as a driver for a 44 GHz terminal transmitter will be described. The amplifier is designed for 2 GHz 1-dB bandwidth centered at 44.5 GHz, with an overall gain of 40 dB. A six-stage design is used to accomplish 500 mW output power. Low cost construction and mechanical ruggedness are emphasized in this design.
    • 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.
    • TELEMETRY-, TELECOMMAND- AND MONITORING SYSTEMS OF EUROPEAN SATELLITE CONTROL STATIONS

      Fröhlich, Horst; Borgmeyer, Johannes; Dornier System GmbH (International Foundation for Telemetering, 1981-10)
      Since years Dornier System have been active, for the European Space Agency (ESA), in the field of development and manufacturing of baseband equipment for Satellite Control Stations. Respective Telemetry- Telecommand- and Station Monitoring Systems have been designed on the basis of microprocessor controlled units which are interconnected by standard interfaces in order to facilitate station integration procedures. The equipment will be integrated in all European Satellite Control Stations of the existing and coming generation. The paper describes the different subsystems its interfaces and software structure.
    • 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.