• Cost Considerations for EHF Satellite Communications User Terminals

      Andrews, E. J.; Robinson, E. S.; Rockwell International (International Foundation for Telemetering, 1980-10)
      Mobile satellite communications at UHF have gained wide acceptance in the past several years. This acceptance has been largely a result of the improvement in communication reliability over other long-range systems such as HF. Deficiencies, however, have been noted with respect to the performance of UHF satellite communication (SATCOM) systems where anti-jam (AJ) or low probability of intercept (LPI) characteristics are of importance. Recent advancements in technology coupled with increased requirements for improved AJ and LPI have focused attention on the EHF frequency range for evolutionary replacement and/or augmentation of UHF SATCOM systems. RF equipment in this frequency range has the potential for the implementation of highly compact terminals for mobile application such as required for airborne force elements. In the next 5-10 years, a wide range of technologies will be applied to the development of EHF user terminals. Critical trade-offs exist between satellite and terminal complexity as well as within the terminal itself. Within the terminal, antenna gain versus HPA power, antenna mounted solid-state PA's versus TWT PA's, phased arrays versus advanced reflector antennas all must be considered. Although the antenna and HPA are the most significant cost drivers, secondary trade-offs, such as antenna gain versus use of paramps or FET's, and synthesizer approaches for fast hop and signal processing implementation also must be addressed. This paper addresses a typical terminal for a small mobile user such as an airborne force terminal. Typical system and spacecraft characteristics are defined and tradeoffs carried out on a parametric basis between various terminal elements to establish cost-performance relationships.
    • Extension of JTIDS Capability via Synchronous Satellite Repeater

      Nilsen, Peter W.; Udalov, Sergei; Axiomatic (International Foundation for Telemetering, 1980-10)
      An approach for extending the JTIDS capability beyond LOS by use of a synchronous satellite relay is described. The concept of a satellite relay introduces certain immediately apparent operational advantages over airborne relays. However, a requirement that the satellite relay be transparent to the basic JTIDS waveform, i.e., same carrier frequency and modulation, introduces some unique satellite repeater design problems. These problems, and their associated system design trade-offs, are discussed along with a potentially feasible design solution. Also, since the JTIDS TDMA format is designed for LOS propagation times, some unique network timing and control problems are introduced by the utilization of a synchronous satellite relay. Therefore, solutions which are transparent to the basic JTIDS waveform and terminal design, while compatible with a satellite network, are also discussed in the paper, along with a candidate baseline solution.
    • Control and Data Transmission System for a Balloon-Borne Ion Mass Spectrometer

      Sukys, Raimundas; Rochefort, J. Spencer; Northeastern University (International Foundation for Telemetering, 1980-10)
      A balloon-borne instrument package is currently being developed by the Aeronomy Division of the Air Force Geophysics Laboratory. The primary instrument is a quadrupole mass spectrometer. Its task is to detect ambient ion and neutral clusters at altitudes of 30 to 40 kilometers. Positive and negative ions in the range of 14 to 1000 atomic mass units (amu) are to be investigated. An aspirated Gerdien condenser and a low emission potential probe are included as supporting instruments. A flight from the AFGL Balloon Facility at Holloman AFB, New Mexico is planned for spring, 1981.
    • Vehicle Telemetry Data in the Vertical Blanking Interval

      Ryan, Thomas J.; BDM Corp. (International Foundation for Telemetering, 1980-10)
      This paper describes how three different developments in digital and video technology have been exploited to provide for the automatic retrieval of data from video tape recordings. By application of the technique of vertical interval data insertion, a pair of 50-bit digital "words" are inserted into two lines of each TV field. The digital words are assembled from a BCD representation of IRIG-B time and both serial and parallel digital data from instrumentation associated with the vehicle. Retrieval of digital time and data annotation from a composite video signal's vertical interval is automatic and yields editing commands and digital data reduction at 3x tape play speeds. This paper defines the functional requirements, describes the implementation concept and provides illustrations of the pragmatic solutions.
    • Configurations for EHF Satellite Communications for Mobile Users

      Chick, R. W.; McElroy, D. R.; M.I.T. Lincoln Laboratory (International Foundation for Telemetering, 1980-10)
      Two-way electronic communications to mobile platforms was initially provided in the HF (3-30 MHz) band. Then, as electronics technology progressed and requirements for increased link availability and capacity emerged, service evolved into the VHF (30-300 MHz), UHF (0.300-3 GHz), and SHF bands (3-30 GHz), with the latter two often involving satellite-based systems. Recently, considerable consideration has been given to utilizing satellite communications systems operating in the allocated EHF (30-300 GHz) bands to provide wide-area coverage, to overcome frequency congestion difficulties, and to provide sufficient bandwidth for projected capacity increases and for interference protection via spread-spectrum modulation techniques. By using emerging spacecraft technologies such as multiple uplink antenna beams, onboard signal processing, and downlink beamhopping, EHF systems can be configured to serve large numbers of small, mobile users. The resulting satellites would be of modest-size, and the associated limited-size user terminals would be less expensive and easier to install and maintain than those for EHF systems which only employ conventional technology. This paper describes several system configuration which use one or more of the above technologies, discusses the advantages of each, and indicates possible spacecraft and terminal implementations.
    • Application of Telemetry to Geological Prospecting in China

      Fan-shuan, Zeng; Feng-kuan, Wang; Beijing Research Institute of Telemetry (International Foundation for Telemetering, 1980-10)
      This paper describes the application of telemetry to petroleum prospecting and coal mine prospecting in China and gives an introduction to the operational features of petroleum prospecting and coal mine prospecting. The logarithmic coding and depth synchronous coding have been adopted to fit these features. The paper also introduces briefly the system scheme and the effectiveness in use. The results of the equipments have abundant capacity, large dynamic range, comparatively high accuracy, flexibility, the high speed gained from computer-aided data processing, and the advantage of being easy to use and less expensive, and consequently are applicable to the developing countries.
    • A General Purpose Military Satellite Communications System Concept

      Brandon, William T.; Strohl, Mary Jane; The MITRE Corporation (International Foundation for Telemetering, 1980-10)
      An interoperable military satellite communications system concept involving proliferated, all-frequency band, microprocessor-controlled satellites is proposed. Network access and control techniques are suggested, and the utility and cost effectiveness in terms of terminal cost savings are explored.
    • Satellite Cluster Provides Modular Growth of Communications Functions

      Wadsworth, Donald v. Z.; Hughes Aircraft Company (International Foundation for Telemetering, 1980-10)
      The orbiting antenna farm or large geostationary platform has been proposed as an efficient method for combining many satellite functions at a single orbital slot. Proponents claim that crossconnecting C, Ku, and Ka band communications networks and perhaps weather satellite readout at the spacecraft permits more efficient use of the available frequency spectrum and fixed frequency earth terminals. However, the expected economy of the large multi-functional platform is offset by its increased complexity and reduced reliability compared to a multiplicity of single-function satellites. A further disadvantage is that costs, development schedules, and introduction of new technology cannot be extended over a span of several years, as can be done with independent satellite launchings. The satellite cluster concept described here offers the platform's feature of interconnectivity, while avoiding its disadvantages. Single-function satellites can be added to the cluster as required, and maintained at distances which are small compared to those between adjacent orbital slots. This paper analyzes the marginal power and weight for providing interconnecting communications links; interconnection bandwidth, attitude control and stationkeeping requirements; and optimum satellite spacings within the cluster.
    • Telemetry System Based on Walsh Functions

      Chishan, Chang; Zhongkan, Liu; Beijing Institute of Aeronautics and Astronautics (International Foundation for Telemetering, 1980-10)
      In this paper a telemetry system based on Walsh functions is described. After a brief introduction of Walsh functions a sequency division multiplex system is introduced. Synchronization problem is discussed in some detail. Finally, experimental results are given to justify the design consideration.
    • 20 GHz Active Aperture for Communication Satellites

      Jones, Donald E.; Motorola, Inc. (International Foundation for Telemetering, 1980-10)
      The trend to higher frequencies for satellite to earth communications, together with requirements for increased reliability and graceful degradation, has resulted in the need for a 20 GHz active aperture transmitting array. In this paper the preliminary design of such an array is discussed. The array is designed for 35 dB of gain and -30 dB sidelobes. Quantized amplitude tapering, gain distribution, phase shifter quantization, prime power requirements, array and element trade-offs are discussed. The impact of multiple beam operation for frequency reuse is addressed.
    • T.V. Receive Only and Digital Data Terminals

      Scientific Atlanta (International Foundation for Telemetering, 1980-10)
      The high standards of equipment availability demanded by today's commercial and industrial users of satellite communications equipment have resulted in a cost-benefit approach to product development. In this paper, the results of such an approach-as applied to several lines of Scientific Atlanta products-indicate that attractive MTBF and MTTR can be achieved with commercial products at reasonable cost. In this paper, an overview of current Scientific Atlanta digital and video satellitecommunications products is followed by the design and manufacturing techniques used to achieve high availability. A case study using the Marisat terminal manufactured for Comsat General shows measured availability data for this nonredundant commercial product.
    • Application of Advanced On-Board Processing to Satellite Communications - Cost/Performance Implications for Technology Development

      Ruddy, J. M.; White, B. E.; The MITRE Corporation (International Foundation for Telemetering, 1980-10)
      Rapidly growing communications services are creating a demand for large capacity communications satellites which are efficient and economical. This demand, coupled with the need for affordable earth terminals and the requirement for a mix of user types, means that future communication satellites must support a complex system structure. Technological development and implementation are clearly needed. The focus of this paper is on-board processing techniques and related technical issues regarding implementation of a multibeam communications satellite which would service a wide range of users in the 1990 time frame. The effect of various forms of on-board signal processing on satellite communication system performance and cost in the 20/30 GHz band is examined. The implications for technological development are discussed in the context of a specific system architecture suitable for use by wideband high rate trunking users and lower rate customer premises services. The particular impact of processing satellite architectures on earth terminal costs is emphasized.
    • AFSCF Planning Towards the 1990's

      Rugg, Charles J.; The Aerospace Corporation (International Foundation for Telemetering, 1980-10)
      The Air Force Satellite Control Facility (AFSCF) came into being over twenty years ago, and since then has evolved into a satellite support network of major national importance. The present configuration of the AFSCF includes seven Remote Tracking Stations (RTS's) situated around the globe plus a central control facility, the Satellite Test Center (STC), located in Sunnyvale, California. (See Figure 1.) Ongoing plans will provide for significant upgrades and additions to the AFSCF network. Two of these which will have a major influence on the operations of AFSCF into the 1990's are the centralization of the real-time processing capability at the STC (Data Systems Modernization) and the implementation of a Consolidated Space Operations Center (CSOC) tentatively planned to be constructed in Colorado Springs, Colorado. These two upgrades to the AFSCF are discussed (see Figure 2) in detail elsewhere in these proceedings under their respective titles.
    • Consolidated Space Operations Center

      Moffat, Margaret H.; Hollander, Sidney; The Aerospace Corporation (International Foundation for Telemetering, 1980-10)
      Now in the planning stage by the Air Force Systems Command Space Division, the Consolidated Space Operations Center (CSOC) will be a secure, dedicated space control center that will provide the Air Force enhanced command and control capability in the late 1980's and 1990's. Tentatively to be constructed in Colorado Springs, Colorado for an initial operational capability date of mid-1986, the CSOC will include a Satellite Operations Center (SOC) and a Shuttle Operations and Planning Center (SOPC). The SOC, an integral part of the Air Force Satellite Control Facility (AFSCF) network and functionally identical to the Satellite Test Center (STC) in Sunnyvale, California, will perform its command and control functions with a modernized data system now under development at the STC, and will support its assigned AFSCF workload. Also, in the event of a catastrophic failure, the SOC will provide austere backup support for workloads normally assigned to the STC, and vice versa. Additional land is being acquired to accommodate the construction of facilities for major new space programs as required. The SOPC, functionally equivalent to portions of the NASA Johnson Space Center Space Shuttle Complex, will perform preflight, flight, and postflight operations necessary to satisfy DOD Space Shuttle vehicle payload mission objectives. The SOPC and the Johnson Space Center (JSC) will be interoperable so as to provide limited backup support for DOD or NASA Space Shuttle missions in the event of catastrophic or extended failure at either location. The development of the CSOC requires major architectural changes for both the AFSCF and NASA. These changes include an expansion of the current AFSCF wideband communications system; interfacing of the AFSCF and NASA communications networks; inclusion of a 32 megabit-per-second (or higher) telemetry processing capability for scientific experiments that will be flown during Shuttle sortie missions; and provision of systems to coordinate operations between Shuttle payload specialists and associated ground controllers.
    • Terrain Reflection Effects on Data Reception from Airborne Vehicles

      Chandler, Charles W.; Electro Magnetic Processes, Inc. (International Foundation for Telemetering, 1980-10)
      Propagation phenomena, particularly the interference between the direct and terrain reflected waves, strongly affect the path loss between the transmitting and receiving antennas. A method of analysis and computer-drawn patterns are presented to show the multi-lobed character and deep nulls, in range-altitude coverage, that result. Type of terrain, polarization, and antenna pattern effects are shown. Application of the results to system design is discussed.
    • Two Interesting Applications of Digital Data Insertion in Video Signals: The TV Display Generator and the Video Countdown Programmer

      Turner, Lester; Datum Inc. (International Foundation for Telemetering, 1980-10)
      The recent development of compact, rugged, reliable and easy-to-use video cameras, recorders, amplifiers, digitizers and monitors has made this equipment increasingly attractive for data acquisition purposes. When analog and/or digital data is combined with video signals, the resulting configuration is a video instrumentation system. Two examples of video instrumentation systems are described in this paper. The TV Display Generator accepts four independent analog signals, modulated IRIG B serial time code, three different standard composite video signals and several digital control signals. The analog and time code signals are digitized and inserted into the composite video input signals for recording and display. The Video Countdown Programmer generates four color and two monochrome standard composite video signals and formats and inserts up to six sets of parallel BCD and ASCII digital data into each video signal. The output video signals are displayed by large screen monitors. As these two systems indicate, the recording and display functions of video instrumentation system provide additional capabilities in data acquisition applications.
    • The Effects of Tape Dropouts on Pulse Compression Recording

      Waggener, W. N.; Sangamo Weston, Inc. (International Foundation for Telemetering, 1980-10)
      It is widely recognized that tape dropouts are the major impediment to error-free recording in high density digital recorders (HDDR). Conceptually, the effects of tape dropouts on error performance can be combatted by error correcting codes, signal design or a combination of the two. In this paper the effect of tape dropouts on wide time-bandwidth signals is considered. Wide time-bandwidth signaling techniques, commonly refered to as pulse compression, would appear to be capable of combatting the effects of short tape dropouts. Although the wide time-bandwidth signals are, to a certain degree, immune to short signal dropouts, an excessive performance penalty is paid when dropouts exceed about 10% of the signal duration. The effects of tape dropouts are shown to effectively reduce noise margin by decreasing the signal detection filter output and by introducing intersymbol interference through increased sidelobe levels.
    • Synchronization of SS/TDMA On-Board Clocks

      Campanella, S. J.; COMSAT Laboratories (International Foundation for Telemetering, 1980-10)
      Satellite switching of TDMA traffic is now recognized as the next step of implementation to be introduced in the evolution of digital satellite communications. The satellite switch must of course be synchronized with the TDMA burst transmissions of the terminals. This paper addresses this synchronization problem. It considers in particular the problem of achieving plesiochronous operation at the satellite/terrestrial network interface and discusses methods which can be used to accomplish such operation. In particular, two methods of implementation are discussed, the first involving control of an onboard clock by feedback from a cooperating earth station via telemetry and the second involving onboard demodulation of the TDMA frame synchronization burst.
    • Satellite Broadcasting for the 80's

      Kiesling, John D.; General Electric Company (International Foundation for Telemetering, 1980-10)
      Satellite broadcasting can supplement existing television services, reach isolated rural populations and provide special services to dispersed populations which, in aggregate, can be quite large. The technology for high power Ku Band (12 GHz) transponders has been demonstrated and examples are available of cost effective consumer-premises receiving systems. This paper describes the technology of satellite TV broadcasting systems, both ground and space, and indicates the salient cost and system parameter tradeoffs versus population served, e.g., cost versus G/T and number of ground terminals, rain fade outage effects and effect of number of satellite beams. Examples of designs, past and future will illustrate possibilities for high power, multiple shaped beam antennas, spacecraft high power generation and sundry problems.
    • On the Characterization of Noise in the Simulation of Nonlinear Wideband Satellite Digital Links

      Jeruchim, Michel C.; General Electric Company, Space Division (International Foundation for Telemetering, 1980-10)
      The prediction of performance (BER) for a digital satellite link possessing typical impairments is a difficult analytical undertaking. When, further, the repeater is nonlinear and the uplink noise is nonnegligible, the difficulty of an analytical approach is greatly compounded. Consequently simulation is becoming increasingly common as a tool for solving the BER-prediction problem. It is often assumed, however, that a link is characterized by a single Gaussian noise source at the receiver. This assumption can lead to considerable error in the weak uplink nonlinear system. For the latter situation we consider in this paper the problem of characterizing an equivalent single noise source at the receiver, which will better account for actual system behavior than the Gaussian source. For this equivalent source we postulate that the pdf is drawn from a family of the form const x exp [ - | x | v] and obtain through simulation the BER performance as a function of v. Comparing these results with Monte Carlo simulation runs shows the possibility of approximately characterizing the complex system's behavior by a single non-Gaussian noise source.