• OSCAR: Your Own Communication Satellite

      Pronko, J. G.; Project OSCAR, Inc. (International Foundation for Telemetering, 1980-10)
      Since the advent of the space age, amateur radio operators and leisure time scientists have been involved in designing and building sophisticated spacecraft to be used for non-profit, educational and scientific communication purposes. The author describes the development of a series of communication satellites known as OSCAR (Orbiting Satellite Carrying Amateur Radio), the first of which was launched "piggyback" in 1961.
    • 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.
    • 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.
    • Telemetry and Control Systems for the Balloon Altitude Mosaics Measurements Program

      Griffin, Jack R.; Thorn, Willard; Poirier, Norman C.; Fike, R. Michael; Hancom Air Force Base; Northeastern University; Oklahoma State University (International Foundation for Telemetering, 1980-10)
      The Balloon Altitude Measurements (BAMM) program is being conducted by the Air Force Geophysics Laboratory. This program is designed to provide infrared earth background measurements and atmospheric IR data in the short wave spectrum. The BAMM flight profile calls for approximately 10 hour flights. These high altitude balloon-borne experiments projected several unusual design problems in telemetry, tracking and payload position, data acquisition, and television control and video transmission. The payload may be rigged for aerial recovery by helicopter. Five telemetry downlinks are required for the scientific, television, and balloon housekeeping data. Three upleg UHF links are used for remote command and control of the balloon vehicle, television system, sensors, and the pointed platform, and for ranging/trajectory data. The innovations and methods used to solve the many instrumentation problems for this exciting and highly successful program are highlighted. To date five successful BAMM balloon flights have been carried out from launch facilities in New Mexico and Mississippi.
    • Telemetry and Location for Long-Duration Balloon Flights

      Lichfield, Ernest W.; National Center for Atmospheric Research (International Foundation for Telemetering, 1980-10)
      Small 3-meter diameter balloons have flown for as long as 744 days, circling the globe 50 times. The balloons carried instrument packages weighing only 200 grams. These light systems require simple low power telemetry location techniques. HF telemetry and sun angle location were used on the original flights. More recently, polar orbiting satellites have collected telemetry and located the balloons. These satellites carry a location system called ARGOS, which locates by measuring the doppler shift in frequency as the satellite overflies the balloon. The doppler location technique requires an ultra-stable balloon transmitter frequency. A new polar-orbiting satellite location system promises an even greater reduction in balloon electronic complexity. This system locates using an interferometer to measure the direction from which the signal arrives. No ultra-stable transmitter is required. At the opposite end of the balloon spectrum are large 20-meter diameter superpressure balloons carrying 250 kg payloads containing complicated experiments. These balloons can theoretically fly for 20 years and will have solar powered propulsion systems that will move them in latitude. The balloon systems will require onboard navigation, high data rate telemetry, and command reception capability. A network of geostationary satellites is needed to provide the required telemetry link. Future location systems should combine orbiting and geostationary satellites to provide accurate global location and real-time data collection.
    • TDRSS Ground Station Software/ADPE

      Bebb, Joan E.; TRW DSSG (International Foundation for Telemetering, 1980-10)
      The Tracking and Data Relay Satellite System (TDRSS) provides data relay and tracking services for other (user) satellites. The ground station performs all the modulation/demodulation functions for, simultaneously, as many as 19 forward (to user spacecraft) and 32 return (from user spacecraft) data channels at K and at S-band. TDRSS is transparent to the data itself; it passes synchronized bit streams directly to/from NASA. The data channels exist on up to 4 communication satellites and are carried on 6 single access and 3 multiple access space antennas. TDRSS relay services are available 24 hours/day, 7 days/week. Individual services using a single TDRS may be maintained for up to 24 hours. Using 3 TDRS', a user satellite may be serviced continually. The TDRSS ground station is a highly automated collection of communication electronics. Automation is achieved through the use of software in a large complex of dedicated computers - 9 DEC PDP 11/70's and a dual processor Univac 1110. The software performs three major functions: * management of the TDRSS resources - spacecraft, ground antennas, demodulators, bit syncs, etc. * computation of user spacecraft tracking/trajectory data * telemetry, tracking and control of the TDRS' The software/ADPE configuration was designed to provide the responsiveness needed to support the TDRSS mission: rapid and flexible scheduling and management of equipment to provide relay to and from NASA; rapid, highly accurate trajectory and tracking computation; ground-supported autotrack for the TDRS single access antennas; simultaneous provision of TT&C functions for multiple TDRS'; and control of the behavior of the Ground Station under abnormal (failed equipment) conditions.
    • TDRSS Ground Segment Implementation

      Hart, R. T.; Harris Corporation (International Foundation for Telemetering, 1980-10)
      The Ground Segment of the TDRS System is a highly complex family of automated communications equipment that is capable of providing a wide variety of ground communications signal processing capabilities to satisfy the special needs of each of the many user satellites. These needs are accommodated simultaneously for as many as 28 user satellites. This paper complements the previous papers in describing the Ground Segment functions and the implementation of the hardware that provides these functions. It describes the seven antennas needed to establish the communications paths to the four TDR satellites that make up the TDRSS. The forward services, return services, tracking services and self-test verification services are described. The descriptions cover the extreme versatility for providing frequencies, bandwidths, modulation/demodulation needs, data formats and data rates that are required by the specific users. Performance characteristics are presented for the key elements of the ground segment.
    • 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.
    • 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.
    • 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.
    • 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.
    • A Poor Man's Balloon Control and Data System

      Laping, Hans; Hansom Air Force Base (International Foundation for Telemetering, 1980-10)
      AFGL has the responsibility to provide command control and TM data systems for many scientific high altitude balloon experiments. The variety of these experiments led to the development of two basic systems: (1) For high data rates and instant command control and IRIG-compatible command and TM system can be used. (2) For long duration, over the horizon balloon flights, when neither the data rate nor the command response time is important, a slow balloon control and TM system can be provided. This paper describes AFGL's simple, inexpensive and slow balloon control and data system. The discussions include the HF command system, the data encoder and its code format, and the ground control station where the scientific balloon data is decoded and displayed. Advantages and disadvantages of the slow control and data system are also treated.
    • Television Applications and Transmission of Digital Data in the Vertical Blanking Interval

      Lopinto, John J.; Home Box Office, Inc. (International Foundation for Telemetering, 1980-10)
      It has become evident that the small piece of spectrum, known as the vertical blanking interval in the baseband video signal, can be almost as important as the video program itself. By design, the first 21 lines in the video signal were left blank to account for retrace tolerances in television receivers. The state-of-the-art is such that now lines 14 - 21 can be used to send ancillary signals and data without being visible on the television screen. Professional test signals have been transmitted for a number of years to give a signature of the transmission medium. Only in recent years, however, has data been transmitted for both housekeeping functions as well as the generation of revenue. This paper will explore the various ways these few lines are being utilized to transmit large amounts of data of all kinds. Applications by both the broadcast and cable industries will be outlined where their application varies. Finally, future trends and considerations will be discussed.
    • Satellite Ground Control System for INSAT

      Fisher, Patrick J.; Ford Aerospace & Communication Corporation (International Foundation for Telemetering, 1980-10)
      The task of controlling and monitoring a domestic communications satellite from transfer orbit injection, through the critical apogee motor firing sequence and the drift orbit to on-station operations is addressed in this paper. The Satellite Ground Control System (SGCS) employs the latest technology, equipment and computer software architecture to perform the necessary tasks of monitoring and controlling the INSAT spacecraft to be launched in 1981. This paper documents an approach which allows cooperation of the host country technological capabilities with the specialized technology required to place a satellite in orbit. A unique feature of this design is the utilization of a single minicomputer to perform both real time telemetry tracking and command (TT&C) and background orbital analysis functions at the Satellite Control Center.
    • 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.
    • 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.
    • A History of Commercial Earth Terminals

      Cuccia, C. Louis; Ford Aerospace & Communication Corporation (International Foundation for Telemetering, 1980-10)
      This paper will discuss the evolution of the communication satellite earth terminal from the standpoint of both user requirements and cost. It will start with the TELSTAR earth terminal and discuss the costs and structures of the early Intelsat and COMSAT earth terminals built in the 1960's. The paper will then trace the cost evolution to the 1970's with the introduction of Standard B and C terminals, 4.5 and 10 meter TVRO earth terminals; domestic earth terminals for communications and data in all parts of the world; and finally the new 56 K bps 5 meter terminals, the SBS terminals, and the direct-to-user terminals (TVRO) of the 1980's.
    • The Revolution in DOMSAT Terminal Cost and Performance Spearheaded by Small Aperture Terminals (SATs)

      Johnson, J. Walter; California Microwave, Inc. (International Foundation for Telemetering, 1980-10)
      This paper traces over the last five years the revolution in DOMSAT terminals from the one million dollar 11 meter INTELSAT B stations to the six thousand dollar 2 meter Small Aperture Terminals (SATs) being used by Broadcast and Wire Services to distribute network programming and wire service directly to the local radio station or newspaper. The key systems architecture, technologies and market conditions that have made this revolution in receive-only earth stations possible are detailed.