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.

      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.

      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.

      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.