• International Telemetering Conference Proceedings, Volume 15 (1979)

      International Foundation for Telemetering, 1979-11
    • Telecommunications for the International Solar Polar Mission

      Chan, Richard J.; TRW Defense and Space Systems Group (International Foundation for Telemetering, 1979-11)
      The International Solar Polar Mission (ISPM) is a joint venture of the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) for each to develop a single spacecraft to carry unique scientific experiment hardware packages. The hardware is designed to gather data for the scientific study of solar properties and interplanetary physics out of the ecliptic plane.
    • Management of Software Development

      Downs, H. Robert; Science Applications, Inc. (International Foundation for Telemetering, 1979-11)
      Development of software is well known as a very difficult management problem. When the software is a part of a complex telemetry system, the management problem becomes particularly complex; particularly if the software is not well defined before implementation begins. This paper discusses some of the problem areas in software management with particular emphasis on the requirements and design stages. In a telemetry system development effort, the system designers must decompose system requirements into requirements on various subsystems. This process is particularly apt to lead to software requirements which are not well defined, impossible to meet or inappropriate for the hardware on which it is implemented. This paper addresses methods of performing and managing this type of software development.
    • U. S. Domestic Communication Satellite Systems

      Martin, D. H.; The Aerospace Corporation (International Foundation for Telemetering, 1979-11)
      Domestic communication satellite (domsat) systems in the United States have a history of 14 years. Currently, several systems are in operation and another will be in early 1981. In recent years, many papers have been published, each describing certain details of a specific system. In contrast, this paper presents an overview and comparison of all the systems. As a background to this survey, the U. S. domsat history is briefly reviewed. The system overview then begins with a look at the satellites. Their basic designs are compared pictorially and through tabular data. Communication subsystems are also compared. The survey then goes on to the terminals, the terrestrial parts of the systems. Representative terminal characteristics are discussed. Finally, the various communication services offered by these systems are described.
    • MMS Command and Data Handling

      Kelley, R. L.; Raymond, H. A.; Fairchild Space and Electronics Company (International Foundation for Telemetering, 1979-11)
      The Command and Data Handling System which is part of the NASA Multi-mission Modular Spacecraft (MMS) represents a versatile time division multiple access approach to processing spacecraft commands and retrieving data on real-time, delayed or preprogrammed basis. This paper traces the command signals from operator keyboard to execution within the spacecraft and telemetry/data signals from on-board spacecraft measurement to display on the operator's CRT page. Key technical features throughout this end-to-end signal processing loop are described and discussed.
    • Control Aspects of Multibeam or Multielement Spacecraft Antennas

      Foldes, Peter; General Electric Company, Space Division (International Foundation for Telemetering, 1979-11)
      With the rapid development of spacecraft systems the trend is toward more sophisticated and larger on-board antennas. Many of these antennas employ an array of radiating elements, either as part of a feed system illuminating a larger aperture optics or as the direct radiators. The main purpose of using multiple radiators instead of a radiator in conjunction with a large aperture is to introduce a much larger degree of freedom in achieving desirable antenna characteristics. If an antenna system contains n independent radiating elements then the amplitude and phase of each of these elements can be selected for desirable results.
    • A Compatible STS/PAM D/RCA SATCOM Telemetry and Command System

      Hoedemaker, R.; Staloff, C.; RCA Astro-Electronics (International Foundation for Telemetering, 1979-11)
      This paper presents a solution to the problem of providing the electrical interface with the NASA Shuttle and PAM D for an RCA Satcom Communications Satellite. The paper addresses the transition to the NASA Shuttle from the present era of expendable launch vehicles as it applies to the command and telemetry electrical interfaces. Final preparation of the spacecraft for launch into the transfer orbit rests with the Orbiter crew rather than the spacecraft contractor launch team. The added dimension of crew safety and the importance of simplifying the preparation task led the requirement for Electrical Airborne Support Equipment (EASE). The conceptual design of this microcomputer-based equipment is described. The EASE monitors the health of the spacecraft and takes adaptive action where appropriate. It also sends prestored command lists to the spacecraft in response to crew-initiated keyboard command functions.
    • Navy Shipboard Weapon Information Telemetry System

      Dahl, Ernie A.; Bates, L.; Naval Ship Weapon Systems Engineering Station (International Foundation for Telemetering, 1979-11)
      The paper presented by NSWSES at the 1975 ITC Conference in Washington, DC, described the Portable High Frequency Telemetry System (PUTTS) being assembled for NATO. This system used the best of the then standard state of the arts commercial components and was used for shipboard missile data receiving/recording and for quick look missile performance evaluation. In 1977 the Naval Sea Systems Command made funds available to update the AN/SKQ-3 system by utilizing the RF assembly similar to that used in PUTTS. This new RF assembly provided dual antennas for (1) a wide angle for verticle launch and initial acquisition; (2) narrow beam high gain for long range tracking. The RF unit also included frequency scan with automatic lock when a signal was received, and sector search. In 1978 funding was received from Australia and Iran to procure additional PUTTS. These units (PUTTS III) were updated to handle faster intercept rates as well as improved range tracking and adapt the new RF features from the SKQ-3 Mod. Added to this were the capability to handle both PAM and PCM data with light weight hardware. These systems were completed and the Australian unit system was delivered after acceptance tests with U.S. fleet operation in the Gulf of Mexico. As a result of these successful improvements a new portable system has been built to (1) adapt microprocessors to the set-up of data format; (2) Provide automatic selection remote control of the RF head within the antenna frame; (3) provide the basic data to make automatic processing possible when and if desired; (4) Add the new low noise GASFET preamp to the system to increase the range; (5) Add capability for four receivers in the space presently occupied by the dual receivers to permit the handling of the new missiles with dual RF outputs and (6) provide the capability of system checking of all modules from the antenna through the system to the paper read-out device. This paper now presents the new updated system combining the state of the art development in programming, remote control, low noise preamps, miniature RF assembly, matrix control programming as well as automatic data set up and selection for data processing.
    • DMSP Block 5D-1 Computer Controlled Spacecraft

      McElroy, Stephen M.; Gomberg, Louis; Beest, Roger Te; SAMSO; RCA/AED (International Foundation for Telemetering, 1979-11)
      The Defense Meteorological Satellite Program (DMSP) Block 5D-1 satellite is the first of a new generation of DMSP long life satellites to utilize onboard programmable computers for spacecraft control functions. During ascent and orbit injection the computers perform the navigation, guidance, and control functions autonomously; during on-orbit operations, they perform attitude determination and control, command and control, and miscellaneous other control functions, with only modest interaction from the ground. Four DMSP Block 5D-1 satellites employing these computer controls are currently on orbit and operational. On-orbit experience shows that performance has exceeded all expectations with respect to reliability and satellite life-time. In addition to providing the control functions for which they were designed, the computers have provided additional benefits by allowing the control systems to be reprogrammed from the ground to overcome hardware failure and degradation in other on-board components. This paper describes the DMSP mission, gives a brief overview of the integrated spacecraft system configuration, and provides the details of the control systems used in the various mission phases. The hardware and software portions of the control systems are described and some examples are provided showing how the reprogrammable capability allowed several orbital anomalies to be overcome and satellite life extended.
    • Reconstructing Pulse-Code Modulation Telemetry Data with Dropouts

      Hull, M. L.; Mote, C. D., Jr.; Lamoreux, L. W.; University of California, Davis; University of California, Berkeley (International Foundation for Telemetering, 1979-11)
      A data handling system was developed which transfers serial pulse-code modulation (PCM) telemetry data from an analog tape to a digital tape for analysis on a digital computer. The PCM data were collected from field experiments in snow skiing which measured the excitation between the ski boot and the ski. PCM data were FM transmitted and stored on an analog tape recorder. In the laboratory, data were decoded from the tape and parallel input to a Nova minicomputer which buffered the data and wrote tapes compatible with a CDC 6400 computer. A custom-built PCM decoder provided control and status commands to drive the minicomputer interrupt logic. The data transfer rate was 50 kbits/s. Special consideration was given to the problem of information losses. Lost data frames were not stored by the minicomputer and the data time series on the digital tape is discontinuous at each loss point. Spectral analysis of data with discontinuities produces erroneous results. Fourier coefficients and power spectra were computed for both continuous and discontinuous signals. Discontinuities caused significant reductions in amplitude and increase in bandwidth of spectrum estimates. Unique software eliminated data discontinuities by reconstructing the original time-base with linearly interpolated pseudo-data. Results are presented which show the enhanced accuracy obtained in spectrum estimates with the reconstructed data.
    • Hardware Compressor Reduces Computer Loading

      Strock, O. J. "Jud"; EMR-Telemetry (International Foundation for Telemetering, 1979-11)
      A hardware Compressor examines measurement data prior to computer entry, discards redundant or otherwise uninteresting words, and passes the appropriate information with tags to a computer. Continuous rates of 100,000 to 1,000,000 words per second are accepted. Under some conditions, 95% to 98% of the data can be discarded while passing every measurement which is of value in real-time analysis.
    • Correlation of Tape Dropouts with Data Quality

      Schoeck, Kenneth O.; Kobylecky, George M.; Vandenberg Air Force Base (International Foundation for Telemetering, 1979-11)
      When recording and reproducing telemetry data, signal dropouts are a prime concern to most tape users. The effect of particular depths and lengths of dropouts on data quality must be known before the acceptability of a tape for a specific application can be determined. This paper discusses the correlation of tape dropouts with data quality when recording predetection and post-detection telemetry data and IRIG timing on wideband instrumentation tape, as well as methods of reducing dropouts.
    • Super High Bit Rate Recording

      Wood, Tracy G.; Ampex Corporation (International Foundation for Telemetering, 1979-11)
      A radically different magnetic recording approach is proposed to solve the very high density and very high data rate requirements of the 1980's. In direct contrast to the industry's traditional approach of head-per-track longitudinal recording is a multi-track rotary helical recorder using narrow tracks. This technique is described. These narrow tracks, in conjunction with a novel development called "Automatic Scan Tracking" (AST), make possible the development of a family of recorders with data rates up to one (1) gigabits per second with user packing densities of five (5) megabits per square inch and a bit error rate performance better than one (1) part in a million (106) without aid of error detection and correction codes.
    • Space Shuttle Payloads Support Capability

      Torres, Frank; Rockwell International (International Foundation for Telemetering, 1979-11)
      The NASA/Rockwell Space Shuttle with its highly versatile avionics and electrical provisions for use by the Shuttle payloads will provide an efficient system for future national space program activities and space program activities from foreign countries. This paper summarizes the avionics and electrical payload capabilities and interface characteristics. It includes a description of the command and data systems interface, the caution and warning system interface, and the aft flight deck accommodations; the electrical power distribution system; and the standard mixed cargo harness.
    • Inertial Upper Stage/Shuttle Orbiter Communications

      Huth, G. K.; Udalov, S.; Axiomatix (International Foundation for Telemetering, 1979-11)
      The Inertial Upper Stage (IUS) system is intended for DOD and NASA space vehicle (S/V) launches from the Shuttle Orbiter. Prior to and during the IUS launch, commands must be transmitted to the S/V and IUS and the telemetry data must be communicated to the Orbiter. This paper describes the communication links between the IUS and the Orbiter, with particular emphasis on the RF link equipment and performance. The transponder equipment carried on board the IUS system is also described.
    • NASA Standard Experiment Command and Data System for Shuttle/Spacelab Payloads

      Kasulka, Larry H.; Wilkinson, Darrell D.; Mcdonnell Douglas Astronautics Company (International Foundation for Telemetering, 1979-11)
      A new equipment command and data system (CDS), being developed by NASA for Shuttle/Spacelab-payload users, takes advantage of the more liberal constraints being offered a Shuttle payload user (i.e., size, weight, and power) to save cost. This Spacelab Payload Standard Modular Electronics (SPSME) system provides an extremely flexible approach derived from the modular design of the CAMAC system. SPSME promises to provide a real cost savings to the space community due to its universal application to most Spacelab experiments. NASA projections based on the mission model for the first 19 Spacelabs using SPSME versus the historical hardware results in approximately $125.4 million savings.
    • The LEASAT Communications Satellite

      Dutcher, G. L.; Lankford, J. G.; Hughes Aircraft Company (International Foundation for Telemetering, 1979-11)
      Beginning in 1982 communication services will be provided to the U.S. Navy by a series of UHF communications satellites known as LEASAT. The communications payload will be carried on a new spacecraft bus developed as an optimum bus for space shuttle launches; the program is the first of its kind to take advantage of the full 15 foot shuttle payload bay diameter. Several new spacecraft design concepts are employed in this optimized bus. The communications payload incorporates transponders in the UHF and SHF regimes. Four distinct types of transponders are employed: wideband, narrowband, relay, and fleet broadcast. The functional characteristics of each type is described in detail. The frequency plan leads to a significant potential for passive generation of intermodulation products, and intermodulation considerations are an integral part of the spacecraft design.
    • Estimating Time to Develop Software

      International Foundation for Telemetering, 1979-11
      The most devastating task ever given to the computer system manager, is that of estimating the manpower and time to develop software. Software development has become almost completely out of control in terms of estimating the manpower and time needed for the complete job, from interpretation of the requirements to the operational readiness date. Just as the hardware design engineer never reaches the ultimate design and thus never concludes his job, so goes the software designer. The difference is, hardware design managers have grown up in this environment and therefore know the pitfalls and stopping points of producing a good, reliable product. The software design manager is less qualified because the field is relatively new, it is very complex, and computer hardware technology is expanding so rapid that software designers cannot catch up. This paper is designed to provide the software development manager categories and rules of thumb for estimating time and manpower requirements for each category of software development. In addition to establishing the standard milestones such as requirements definition, specification, design, coding, checkout, verification and validation, consideration is given on how to keep the Ford requirement from turning into a Cadillac capability.
    • The Woe's of the Computer System Manager

      International Foundation for Telemetering, 1979-11
      The software has been designed, coded, and entered into the computer -- now comes the big task of verification and validation. This paper develops several system approaches, technical evaluation criteria, and key milestones for managing the progress, technical excellence and completion of this process. This is the phase of software development that becomes very difficult if a good design and design review has not been performed. In short, a well intentioned capability now becomes a "fair" design with patches installed to make it work. It is the number and type of patches to make it work that causes the software package to rapidly get out of hand. These problems will be discussed.
    • Landsat D High Density Tape Recorders

      Montgomery John H.; Martin Marietta Corporation (International Foundation for Telemetering, 1979-11)
      High density tape recorders are being provided by Martin Marietta Corporation to facilitate Landsat D data acquisition and processing. High rate data form the Landsat D Thematic mapper and from the multispectrial scanner are to be stored on high density recorders of 42, 28, and 14 track configurations. Successive stages of data processing will utilize higher error-free reproduce techniques and tape systems will provide ease of operation with a variety of differing record and reproduce data rates. The design and implementation of these recorders will be discussed.