• THEORY OF PHASE DISTORTION IN MAGNETIC TAPE RECORDING

      Hedeman, Walter R., Jr. (International Foundation for Telemetering, 1982-09)
      The locus of recording when using IRIG standard bias methods is deduced from data on phase distortion presented by the author at ITC 1972. Contrary to popular opinion recording does not occur at the trailing edge of the record gap. At the maximum depth of recording it takes place near the center of the record gap, and in the surface layers next the record head approximately one half the record gap length past the trailing edge of the record gap.
    • TRACKING AND DATA RELAY SATELLITE SYSTEM STATUS

      McMullen, Malcolm; Assistant Vice President-Advanced Planning Space Communications Company (International Foundation for Telemetering, 1982-09)
      The Tracking and Data Relay Satellite System (TDRSS) is approaching launch readiness, with operations scheduled to commence in 1983. This paper describes TDRSS including the commercial communications or Advanced Westar (AW) components and the launch, network, and test elements being employed to bring the system to operational readiness for user support. Users and user equipment are also discussed.
    • TRANSMISSION OF THERMAL IMAGE DATA USING PLUSE CODE MODULATION*

      Johnson, F. Bruce; Colorado Video, Inc. (International Foundation for Telemetering, 1982-09)
      This paper presents a method for synchronous conversion of infra -red image data to a Pulse-Code Modulation (PCM) bit stream for recording on instrumentation tape recorders. The PCM data recording method provides an improvement over analog FM recording in signal to noise ratio, horizontal resolution, and speed of data formatting. The methodology was applied to the design of a PCM encoder for an AGA model 680 Thermovision camera. The extension of the design to other devices is discussed. Considerations for the display of real-time and reduced speed data display on conventional television monitors are presented.
    • TRANSPORTABLE/MOBILE TERMINALS (TMT)

      Sullivan, James F.; Ford Aerospace & Communications Corporation (International Foundation for Telemetering, 1982-09)
      Recent policy statements from senior Air Force personnel places a high priority on the survivability of “deliverable products” from space systems, throughout the conflict spectrum. The timely delivery of these products is dependent on the endurability of the spacecraft, the bit-stream carrying the products, and the ground terminals. Transportable/Mobile Terminals afford a viable option to provide a control segment that can be balanced with the endurability of the space and user segments. This paper examines Transportable/Mobile Terminals whose mission is to provide tracking, telemetry and command support to mission satellites through the conflict spectrum. The role and relationship of TMT’s in the totality of the Satellite Command and Control architecture is discussed in an operational, as well as technical, context. Topics of discussion include threats and countermeasures, sensitivity of design to requirements, the impact of satellite autonomy and the relationship of TMT’s to other planned improvements to the Satellite Command and Control architecture.
    • UPLINK COMMAND STRUCTURE WITHIN THE SPACE SHUTTLE ORBITER

      Lasken, Walter W.; Rockwell International (International Foundation for Telemetering, 1982-09)
      This paper presents an overview of the various types of uplink commands available for attached or detached payloads and discusses in detail the manner in which the Space Shuttle orbiter common set and stand-alone computers accept and process these commands. Command and data processing within the orbiter systems during ascent and on-orbit operation are also discussed. The uplink command formats, as they relate to the data processing system, are presented in some detail.
    • Utilization of Fiber Optics in Large Scale Landline Telemetry Systems

      Saulsberry, Garen J.; Willis, James L.; New Mexico State University (International Foundation for Telemetering, 1982-09)
      The large-scale landline telemetry system may benefit from the application of fiber optics. With present technology, practical means exist to design, implement, and test longdistance, data-transmission systems using fiber optics. Fiber optics and Computer Automated Measurement and Control (CAMA) equipment provide application and tradeoff advantages over a hard-wire system. Procedures for equipment verification must be developed to confirm and verify system performance of the design criteria. Practical computations may be made using values representative of actual system performance. A solution is provided to a typical data transmission problem.
    • WHITE SANDS MISSILE RANGE (WSMR) A PHASE - DIFFERENCE MEASURING TRACKING SYSTEM

      PARRA, MARIO Z.; National Range Operations Directorate (International Foundation for Telemetering, 1982-09)
      The Phase Difference Measuring (PDM) system is an RF interferometer object tracking system which utilizes the object’s radiated telemetry power spectra for tracking purposes. The PDM system is being developed in-house at White Sands Missile Range as a highly mobile electronic angle measuring system, to augument existing position measuring capability in range instrumentation systems. The system is comprised of two Remote Data Acquisition Stations (RDAS) and a Cosine Conversion Facility (CCF). Each RDAS is comprised of two antenna arrays configured as crossed baselines. The RDAS equipment utilizes high speed RF switching in a time sharing technique designed to reduce the amount of hardware required at the remote sites to produce direction cosines. The CCF collects two direction cosines from each RDAS, it then transforms the direction cosines to position data for subsequent transmission to a Range Control Center. This paper will provide basic system theory, explain the proposed antenna PF switching techniques, and also the computer simulation analysis for a baseline consisting of two pair of antennas.
    • WHITE SANDS MISSILE RANGE (WSMR) TELEMETRY TRACKING IMPROVEMENTS

      Pedroza, Moises; White Sands Missile Range (International Foundation for Telemetering, 1982-09)
      The WSMR Telemetry Tracking Systems consist of ten (10) automatic trackers and four (4) manual trackers. These trackers operate in the frequency ranges of 1435 to 1540 MHz and 2200 to 2300 MHz. Two Telemetry Acquisition Systems (TAS) with 24-foot parabolic antennas are located at fixed sites. A 6-foot parabolic antenna system has been converted from a mobile unit to a fixed-site system. Seven Transportable Telemetry Acquisition Systems (TTAS) with 8-foot parabolic antennas can be located on and off the range along with a mobile microwave relay station to support range tests. The RF subsystems on the seven TTAS’s have been miniaturized and integrated with the feed assembly resulting in a vast improvement in autotrack reliability. The digital slave tracking capability of the seven TTAS’s and two TAS’s has been improved by a joint effort between two WSMR organizations. Tracking System Interface (TSI) hardware and software were both developed in-house at WSMR by the Instrumentation Directorate. The National Range Operations Directorate, Data Collection Division, Telemetry Branch interfaced and installed the TSI to the tracking systems. The TSI utilizes two (2) Z80 microprocessors and is capable of slaving to instrumentation RADAR data in one of two modes. The first mode is dependent on the UNIVAC 1108, WSMR real-time computer complex, to convert the RADAR XYZ data to site oriented azimuth and elevation data. The second mode allows the telemetry trackers to accept RADAR XYZ data directly and perform its own coordinate conversion. An additional feature of the TSI is the test mode for self-checks, servo tests, and system readiness tests.
    • WIDEBAND MODEM CHARACTERIZATION TESTING

      Finn, Gerald T.; The Aerospace Corporation (International Foundation for Telemetering, 1982-09)
      As part of an investigation into the causes for random, unexplained data “dropouts” on a Defense Satellite Communication link between the Air Force Satellite Control Facility, Sunnyvale, California and the Indian Ocean Remote Tracking Station, a number of tests were conducted to characterize the performance parameters of the wideband modems used on the link. These tests were used to measure the loop parameters of the modem Carrier and Timing Recovery Loops and to determine the modem sensitivity to RF phase disturbances, data rate variations and various repetitive bit patterns. This paper describes the test techniques used and the results obtained.