• Application of Intersatellite Links to Collocated Telecommunications Satellites

      Welti, G. R.; COMSAT Laboratories (International Foundation for Telemetering, 1980-10)
      A satellite communications system employing a pair of collocated advanced satellites is examined. The new 6/4-GHz bands allocated by the 1979 WARC are exploited to provide a nominal bandwidth of 5,440 MHz for a total capacity of 56,000 channels. The two satellites have an intersatellite link operating in the 32.5- and 23-MHz bands over a 6-km distance. Up to ten 80-MHZ transponders can be cross-strapped. The total mass of each spacecraft is about 1,135 kg.
    • International Telemetering Conference Proceedings, Volume 16 (1980)

      International Foundation for Telemetering, 1980-10
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • Adaptive Rain Fade Compensation

      Rautio, James C.; General Electric Space Division (International Foundation for Telemetering, 1980-10)
      Any satellite communications system operating near 20 GHz will occassionally experience deep fades due to rain attenuation. To maintain a high grade of service in spite of these fades such a system must have a large available margin. An approach to providing this margin in a high capacity FDMA communications satellite without requiring exorbitant spacecraft power or ground station antenna diversity is to dynamically provide a large margin to those links experiencing deep fades while maintaining only a small fade margin on all other links. This paper presents a brief description of FDMA systems; single beam SCPC operation, multiple beam satellite switched FDMA (SS-FDMA),and investigates the optimization of the dynamic FDMA links in a severely fading environment. A solution taking into consideration transponder intermodulation distortion, cochannel and cross polarization antenna interference (in multiple beam antenna systems) and rain fade statistics is derived. The system is optimized with respect to minimum required thermal signal to noise ratio under peak interference conditions. A sample system configuration is presented which shows that such systems can achieve availability approaching 0.9999 at Ka-Band.
    • The Air Force Satellite Control Facility

      Konopasek, L. Ken; Kluetmeier, Jorn; The Aerospace Corporation (International Foundation for Telemetering, 1980-10)
      The Air Force Satellite Control Facility (AFSCF) originated over twenty years ago, and has evolved into a global satellite support network. This global network includes seven Remote Tracking Stations (RTS's), support elements, and the Satellite Test Center (STC) located in Sunnyvale, California. The AFSCF provides real-time telemetry, tracking, and command support to Department of Defense (DOD) spacecraft and launch vehicles. Since its inception in response to changing DOD space support requirements, the SCF network has grown through expansion and modernization of its tracking, data processing, and communication capabilities. This paper discusses the past, the present, and projected AFSCF in support of the DOD space programs and including the Space Transportation System (STS).
    • 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 Evolution of the Spaceflight Tracking and Data Network (STDN)

      Hocking, William M.; NASA/Goddard Space Flight Center (International Foundation for Telemetering, 1980-10)
      On July 29, 1955, President Eishenhower announced that the United States would launch an "Earth Circling" satellite as a part of the U.S. participation in the International Geophysical Year (IGY). Project Vanguard was this country's first efforts in space. It was the Soviet Union, however, that inaugurated the space age by launching Sputniks 1 and 2. Then, after the failure of the first Vanguard launch test, the President authorized the use of a military missile. The Army's successful launch of Explorer I was followed by the successful launch of the Vanguard I satellite. Thus, with two Soviet and two American satellites in six months, the space age was born. The Minitrack Network, the first worldwide satellite tracking capability (1957-1962), evolved into the Satellite Tracking and Data Acquisition Network (1960-1966). The Mercury Network, which became operational in 1961, was the foundation for the Manned Space Flight Network which was also to support the following Gemini and Apollo missions. The NASA Communications Network (NASCOM) began to take shape in the early 1960s. All of these functions began playing together (1965) and were consolidated in the early 1970s as the Space Tracking and Data Network (STDN). The STDN has supported both the manned and scientific missions during the 1970s. The concept of spacecraft tracking support from a satellite system in synchronous orbit began in 1966. Feasibility studies for this Tracking and Data Relay Satellite System (TDRSS) were completed in 1971, the definition phase was completed in 1973, and the contractor-owned government leased TDRSS system is expected to be operational in 1983. This paper will discuss the historical and technical aspects of these satellite tracking systems that have supported our space program from its beginning in 1955, and will take a brief look at the future.
    • Extremely High Frequency (EHF) Technology Development

      Holley, Thurson C.; HQ Space Division (International Foundation for Telemetering, 1980-10)
      The most common projected deficiencies for military satellite communications users are greater anti-jam protection and additional capacity and/or channelization. To a first approximation, these deficiencies are being addressed by moving service to the EHF frequency band in the late 80's and early 90's. However, significant technology development and demonstration are necessary if we are to provide reliable communications with high confidence at these frequencies. The generic technologies presently under investigation or planned for the near term include power amplifiers, adaptive antennas, and hardened processors. The plan is to design pilot transponders incorporating these technologies that will be placed in orbit to demonstrate the technology, assist in terminal development and testing, develop and verify operational concepts, and provide initial residual EHF service to selected users.
    • An EHF (Q-Band) Receiving System

      Tomita, C. Y.; Hubbard, Ray; Rockwell International (International Foundation for Telemetering, 1980-10)
      Operating communication systems at EHF offers the important advantages of the improved antijam performance (wider bandwidth availability) and low probability of intercept. However, space rated communication hardware for operation at EHF is not readily available. Using advanced MIC technology, low noise frequency synthesis techniques and a subharmonic mixing scheme, Rockwell International designed, developed and tested a frequency hopped, 8-ary FSK modulated, Q-band receiving system for satellite applications. Detailed analyses were correlated with the experimental test data obtained in Rockwell's ASCOT Laboratory. These test results, along with key design approaches in hardware and synthesizer designs are presented in this paper.
    • 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.
    • The Large Geostationary Platform and the Real World

      Board, John E.; General Dynamics Convair Division (International Foundation for Telemetering, 1980-10)
      The Space Shuttle will make it possible to place large complicated structures in orbit. The large geostationary platform is a prime candidate for Shuttle launch. A single communications platform placed in geostationary orbit over the United States could alleviate the growing problems of orbit and spectrum congestion by providing communications capacity equal to a large number of conventional satellites at substantially lower cost. A variety of nontechnical and institutional problems such as platform ownership and control, user participation, financial support, and political acceptance must be resolved along with the technical issues of platform/payload design, fabrication, and integration. This paper discusses the institutional aspects of large geostationary platform implementation; presents important economic and political tradeoffs; and identifies potential legal and social problems likely to influence acceptance of the multi-payload, multi-mission concept.
    • The NASA Communications R & D Program

      Durrani, S. H.; NASA Headquarters (International Foundation for Telemetering, 1980-10)
      About two years ago NASA decided to reactivate its communications R&D program, which had been phased down in 1973. The new program focuses on three major areas: technology development in the 30 and 20 GHz bands for wideband communications; system definition for an integrated terrestrial and satellite-aided system for land mobile communications in the 860 MHz band; and development of system concepts and pilot networks for applications data services. The paper summarizes the new activities in the three areas and describes their status and plans.
    • 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.
    • Bit Error Rate Performance of High Density Tape Recorders for Image Processing

      Heffner, Paul; NASA/Goddard Space Flight Center (International Foundation for Telemetering, 1980-10)
      The image processing facility at the NASA/Goddard Space Flight Center utilizes high density tape recorders (HDTR's) to transfer high volume image data and ancillary information from one system to another. For ancillary information it is mandatory that very low bit error rates accompany the transfers. The facility processes approxilately 10¹¹ bits of image data per day from many sesnors, involving 15 independent processing systems that require the use of HDTR's. The original purchase of 16 HDTR's provided 2 x 10⁻⁷ bit error rate as specified. In order to improve the error rate NASA contracted the original supplier of the HDTR's to upgrade the recorders with error correction capability, and successfully achieved the 100 to 1 bit error rate improvement sought by NASA. This paper provides the requirements and conceptual approach to improving HDTR performance and discusses the general technique used to improve the bit error rate. Comparisons are made of actual performance of the HDTR's before and after the modification.
    • 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.
    • Laser Communications Space Experiment

      Linford, R. M. F.; Speno, F. G.; McDonnell Douglas Astronautics Company (International Foundation for Telemetering, 1980-10)
      A laser communications (Lasercom) payload is to be flown on board the Air Force P80-1 (Teal Ruby) spacecraft. An experiment is to be conducted between laser transmitters at White Sands, NM and the spaceborne receiver to demonstrate the feasibility of Lasercom uplinks. An optical telemetry downlink is also included, and an experiment option will provide for an aircraft-to-space experiment. Details of the experiment and the flight hardware will be described.