• International Telemetering Conference Proceedings, Volume 16 (1980)

      International Foundation for Telemetering, 1980-10
    • 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.
    • 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.
    • INTELSAT VI Spacecraft Concepts

      Cantarella, G. P.; Nadkarni, P.; INTELSAT (International Foundation for Telemetering, 1980-10)
      The growth of international telecommunication traffic during the next decade leads to the requirement for large capacity satellites. Some of the communications requirements to be met by the INTELSAT VI satellite are: a capacity of 75,000 channels, full connectivity of the earth station network, and antenna coverage reconfigurability by ocean region. To achieve these goals, new communications techniques and technologies need to be used, such as: multiple beam antennae and satellite switched time division multiple access (SS/TDMA). Improvements in the spacecraft design and advanced spacecraft technologies are necessary not only to meet the communications performance requirements, but also to satisfy the requirement of compatibility with launch by either ARIANE IV or the Space Transportation System.
    • GPS Receiver Simulation and Software Verification

      Holmes, Jerry D.; Budde, Steven R.; Texas Instruments Incorporated (International Foundation for Telemetering, 1980-10)
      The GPS receiver is a receiver capable of tracking the signal from a Global Positioning System (GPS) satellite containing carrier and code tracking loops characterized by their bandwidth and order. A math model of a CPS receiver that uses Monte Carlo techniques to simulate the many effects to be modeled if one is to predict the performance of a GPS receiver when it is operating near its SNR threshold is described. Among these are: (1) predetection filter characteristics, (2) dynamic stress effects, (3) phase or frequency loop error characteristics, (4) envelope detector algorithm, (5) postdetection filtering characteristics, (6) code loop error characteristics, (7) noise sample generation with proper degree of correlation, (8) effect on carrier and code loops when carrier oscillator has a frequency error, (9) effect on carrier and code loops when code loop has a phase error, (10) sampled data effects on carrier and code loop filters and digital oscillators, and (11) threshold improvement as a result of narrower loop bandwidths when inertial aiding is possible. By imbedding a modified version of this GPS receiver model in an interactive software development tool, the verification of actual digital receiver software in a simulated real-time environment can be performed. The design, implementation, and use of such an interactive software development tool is described in the second half of this paper.
    • Telematics and Satellites

      Hannell, Sigmund; European Space Agency (International Foundation for Telemetering, 1980-10)
      Today's European Data Communications Networks, independent of whether the network is packet or circuit switched, are mainly designed to serve interactive terminal generated operations at information rates compatible with voice grade channels. The satellite link on the other hand, possesses some unique but versatile properties when used as a data communication medium. In fact, the satellite link in conjunction with modest sized Earth stations located close to, or on the premises of the users would provide a desirable complement to European Data Communications facilities adding, among others, high speed and multidestination capabilities to the existing data networks. The capability to transfer computer files and record messages containing large volumes of binary information, via fast and efficient satellite links enables a range of new applications for telematics systems to be realized. For example, electronic mail types of systems requiring the fast transfer of digital document records would benefit especially from the capabilities of the satellite link.
    • Open-Loop Nanosecond-Synchronization for Wideband Satellite Communications

      Holmes, W. Morris; TRW DSSG (International Foundation for Telemetering, 1980-10)
      Successful satellite communication systems, providing service to thousands of users, must feature very inexpensive earth terminals. As many functions as possible must be transferred to the satellite, or a central control station, to reduce terminal complexity and cost. When satellite processors are used to demodulate, route, and error-correction decode and encode the communication channel data synchronization requirements can strongly affect system costs. Time Division Multiple Access (TDMA) is an efficient technique for efficiently distributing satellite services among many system users. Traditional TDMA synchronization techniques feature independent synchronization of each system communication data burst. This is expensive in terms of hardware complexity and system overhead efficiency. Demodulators and data bit-synchronizers must be designed to acquire during short burst preamble times, and unique-word-defectors must be provided to identify the burst time-division-multiplex reference. Burst preambles consume a significant portion of the available communication time, or force long frame periods with expensive buffers, as the number of independent communication channels becomes large. This paper discusses a synchronization technique for use with an onboard processing satellite communication system. The satellite oscillator is used as the system time reference, and as the frequency source for all downlink carriers and data clocks. Downlink timing is established at each system earth terminal by a combination of carrier and dataclock tracking, and a downlink timing epoch signal consisting of one bit per TDMA data burst. Uplink timing is established by an open-loop range prediction process, utilizing precision ephemerides calculated and distributed by the central control station. Overall timing accuracy of the uplink signal at the satellite receiver of ±7 nanoseconds allows unambiguous identification of each data bit position in a 128 Mbps TDMA burst. This is accomplished with simple, inexpensive terminal hardware using available crystal oscillators for time/frequency references and digital synthesis techniques that may be implemented in digital LSI chips. This paper presents terminal hardware block diagrams, satellite block diagrams, and central control station algorithms for the required timing synchronization functions. Error budgets for the identified error sources are also presented.
    • Device Independent Software and Hardware

      Kasser, Joseph; Thorne, Richard; Communications Satellite Corporation (International Foundation for Telemetering, 1980-10)
      The INTELSAT V Communications System Monitoring (CSM) network consists of 11 worldwide installations and a centralized data processing/display facility. Each installation is slightly different from the others due to the local station equipment. The CSM installation consists of a number of control and monitoring equipment interfaced to a HP-1000 minicomputer via the IEEE-488 Bus. This paper describes the modular approach taken in the design of nine pieces of control and monitoring equipment that allowed 27 different units, including differences due to sites and antennas, to be designed within a period of three months. The paper discusses the communications protocols and the device independent software used, to speed the development and debug time.
    • Ground Mobile Forces Tactical Satellite Terminals

      Rurak, Stephen F.; US Army Satellite Communications Agency (International Foundation for Telemetering, 1980-10)
      To supplement its communication capabilities, the US Army has developed a family of small, mobile, relatively low cost, Satellite Communications Terminals. Designated as AN/TSC-85 and AN/TSC-93, the Ground Terminals provide Satellite Communication links using the SHF Band. The terminals have a similar design resulting in a high degree of commonality allowing for lower logistics and operational costs. A special signal processing equipment permits nodal (multi-point) and non-nodal (point-to-point) communications. Both terminals are designed to operate from a standard, field power generators as well as from a variety of other power sources. The terminals can establish communications within thirty minutes of arrival on site.
    • Small EHF/SHF Airborne SATCOM Terminal

      Johnson, Allen L.; Joyner, Thomas E.; Wright-Patterson Air Force Base (International Foundation for Telemetering, 1980-10)
      A fifth generation airborne microwave satellite communication system is currently under development. The terminal which operates in the EHF and SHF bands is designed to provide secure, anti-jam communication for the airborne command post fleet of EC-135 aircraft.
    • 30/20 GHz Demonstration System for Improving Orbit Utilization

      Holmes, W. M., Jr.; TRW DSSG (International Foundation for Telemetering, 1980-10)
      The NASA LeRC 30/20 GHz Satellite Communications Program is developing a number of technologies to reduce satellite orbit/spectrum crowding and prevent saturation of our domestic United States Communications capabilities in the 1990 to 2000 decade. Developing the basic hardware technology to operate at 30 and 20 GHz provides 2.5 GHz of new communications bandwidth. This 2.5 GHz additional communications bandwidth is not the primary benefit of the program, however. Rain losses are severe at 30 and 20 GHz, and innovative techniques are required for systems which are both reliable and economic. Techniques being developed include large satellite antennas with simultaneous multiple fixed and multiple scanning beam capabilities. These provide high antenna gain to increase communications margin and frequency reuse capability through beam isolation, while providing complete coverage of the United States. Effective communication bandwidths from a single satellite location can reach ten's of gigahertz, with the communication capacity tailored to match the very nonuniform geographic demand pattern. Satellite onboard processing consisting of demodulation, adaptive forward-error-correction (FEC) decoding and coding, routing of hundreds of thousands of channels to thousands of terminals, and remodulation with independently optimized uplink and downlink modulation structures is being developed. The onboard processing reduces the scanning antenna requirements, allows more effective frequency reuse, and increases the rain margins by adoptively using system margins to support terminals currently experiencing rain. All of the functions described can be performed with reasonable satellite weight, thermal, and power impacts by using large scale integration (LSI) to implement the digital data processor. By designing the onboard processor with parallel internal structure, the hardware can be made extremely reliable (high level redundancy) and the number of LSI chip types required is relatively small. The antenna and onboard processing techniques are readily adaptable to C-band and Kuband, as well as Ka-band. Deployable antennas may be required at the lower bands, but precision deployable antenna designs are available and the feed structures scale directly. Frequency reuse of all three commercial communication bands should greatly ease the orbit crowding problems now being experienced in C-band, and should allow United States domestic communications to accommodate any desired expansion in the next two decades.
    • Data Distribution Within a Local Network Using Fiber Optics

      McCaskill, Richard C.; Canoga Data Systems (International Foundation for Telemetering, 1980-10)
      With the increased use of data communications and telecommunications by major corporations, the data communications managers are finding it increasingly more difficult to interconnect their networks in a cost-effective and efficient manner.
    • 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.
    • 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.
    • High Speed Video Photography

      Silberberg, George G.; Naval Weapons Center (International Foundation for Telemetering, 1980-10)
      The objective of the Metric Video program at the Naval Weapons Center is to achieve photographic film speeds and resolution with video camera and recording techniques. By combining a phase controlled shutter with a standard high quality video camera, a system has been developed that produces well defined images suitable for determining accurate and instantaneous measurement of time versus motion. The new synchronized shuttered video cameras are replacing motion picture cameras which use expensive film and require considerable time to produce an image for data analysis.
    • 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.
    • 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 Communications Platform -- Key to Affordable Services for the Small User

      Bowman, R. M.; General Dynamics (International Foundation for Telemetering, 1980-10)
      The paper will start with a discussion of the economics of communications and small users. It will be shown that the key is reduction of ground segment costs (which today far exceed that of the space segment) by elimination of the "tails" and by reducing the size and complexity of earth stations. The resulting services are a Customer Premise Services (CPS) network and a mobile service. The basic technical requirements of these services are discussed.
    • 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.