• BUBBLE MEMORY INSTRUMENTATION PACKAGE REPLACES DATA LINK IN PARACHUTE TEST SYSTEM AT NWC

      Rieger, James L.; Naval Weapons Center (International Foundation for Telemetering, 1982-09)
      A bubble-memory recorder for data taken from a parachute-measurement system is used to replace UHF telemetry using FM subcarriers. Significant savings in manpower for the test results, along with greater data quality and simpler, more repeatable data playback. New devices and a ground-based playback decommutator provide greater utility and normally end the requirement for a ground station.
    • CARRIER-DETECTOR EXTENDS ACQUISITION RANGE OF BPSK

      Chu, Peter; DECOM SYSTEMS, INC. (International Foundation for Telemetering, 1982-09)
      The capture and tracking range of a Costas type BPSK (QPSK) demodulator is limited by its loop bandwidth, which is determined by the synchronization threshold at different Signal-to-Noise Ratio. A frequency locked scheme, which consists of a carrier detector and digital control network, has been developed to work in parallel with the Costas loop, so the BPSK (QPSK) demodulator would be automatically led to its pull-in range at low Signal-to-Noise Ratio. The probabilities of false dismissal for signal and false alarm signal absent are analyzed.
    • A COMMUNICATION SYSTEM ARCHITECTURE FOR INTEROPERABLE SYSTEMS

      LaVean, Gilbert E.; Sonderegger, Ronald E.; Defense Communications Agency (International Foundation for Telemetering, 1982-09)
      This paper describes a Worldwide Digital System Architecture that was developed in response to tasking from the Office of the Secretary of Defense to the Defense Communications Agency (DCA). This tasking directed DCA to develop a Worldwide Digital System Architecture in coordination with the Military Departments, the TRI-TAC office, and other interested agencies and commands. The main purpose for developing this architecture is to take a first step toward assuring that the many command and control communications and information processing systems are sufficiently interoperable in order to achieve needed survivability and endurability.
    • COMSAT SATELLITE CONTROL NETWORKS

      Johnson, Charles E.; Communications Satellite Corporation Palo Alto (International Foundation for Telemetering, 1982-09)
      The COMSAT family of companies is actively involved in the operation of the Intelsat, COMSAT General, and Satellite Business Systems (SBS) ground networks which currently control twenty-five communications satellites utilizing three control centers and thirteen ground stations with forty-five antennas. Satellites controlled include INTELSAT IV (7), INTELSAT IVA (5), INTELSAT V (4), COMSTAR (4), MARISAT (3), and SBS (2). COMSAT also operates a launch services network consisting of a COMSAT Launch Control Center and Intelsat ground stations, as required, to guide spacecraft to the proper orbit station. Intelsat V flight 4 was launched in March 1982. Two additional Intelsat V’s and one SBS are scheduled for launch this year. The latter will be on the first commercial shuttle mission. The ground control networks contain a commonality traceable to COMSAT’s influence in the design of the satellites and experience in the control of communications satellites dating back to the launch of the Early Bird in 1965. This paper presents an overview of operational and planned networks in which COMSAT plays a significant role.
    • CONSOLIDATED SPACE OPERATIONS CENTER (CSOC)

      Smith, Douglas L.; Launch and Control Systems Acquisition Space Command Los Angeles AFS (International Foundation for Telemetering, 1982-09)
      The Consolidated Space Operations Center (CSOC) will fulfill the nation’s need for an endurable and secure facility for the command and control of DOD Shuttle and satellite missions. For greater endurance, economy, and efficiency, it capitalizes on technical opportunities to integrate satellite-control capabilities. Additionally, CSOC functionally internets military and civilian resources to support military space operations.
    • A DATA MEMORY SYSTEM FOR A SEAFLOOR EARTHQUAKE MEASURING INSTRUMENT

      Ryerson, D. E.; Lopez, A. A.; Sandia National Laboratories (International Foundation for Telemetering, 1982-09)
      A Seafloor Earthquake Measurement System for measuring strong motion seismic data has been developed and tested by Sandia National Laboratories as part of the Department of Energy Offshore Instrumentation Program. The system’s function is to gather data for the design and regulation of offshore structures such as oil platforms and pipelines. The seafloor package is a self-contained unit capable of operating unattended for up to one year with data readout on command via an underwater acoustic telemetry system. One of the problems with such a system is the large memory required to store seismic data. This memory also must consume very little power to conserve battery life. To meet these conditions a combination low-power CMOS buffer memory and a one-million-bit magnetic bubble main memory with switched power was developed. This paper describes these memories and how they are controlled by a microprocessor to save the “best” data since the last data readout.
    • DESIGN OF A FOUR-CHANNEL, 50 MBPS, STATISTICAL MULTIPLEXER AND DEMULTIPLEXER

      O’Donnell, John T.; Digital Communications AYDIN MONITOR Systems (International Foundation for Telemetering, 1982-09)
      This paper discusses the design of a 50 Mbps Statistical Multiplexer and Demultiplexer, Model 781, manufactured by AYDIN MONITOR Systems of Fort Washington, PA. Two Model 781s connected through a 50 Mbps communications link constitute a full-duplex, 4-channel data link with a maximum aggregate throughput capability of 48 Mbps.
    • DIGITAL TV TRI-STATE DELTA MODULATION SYSTEM FOR SPACE SHUTTLE KU-BAND DOWNLINK

      Udalov, Sergei; Huth, Gaylord K.; Batson, Bartus H.; Roberts, Donald; Axiomatix Corp.; NASA/Johnson Space Center (International Foundation for Telemetering, 1982-09)
      The anticipated requirements for Shuttle Orbiter Ku-band downlink communication include the transmission of a digital video signal which, in addition to accommodating the black-and-white TV pictures, must also be able to relay to the ground the color TV information encoded in either field-sequential or NTSC color formats. Furthermore, at the expense of additional onboard hardware and increased bandwidth due to the digitization process, the picture privacy feature can be provided for the downlink. Thus, an objective for the future Space Shuttle TV equipment is the development of a digitization technique which is not only compatible with data rates in the range of 20 -30 Mbps, but also provides good quality pictures. This paper desribes a tri-state delta modulation/demodulation (TSDM) technique which is a good compromise between implementation complexity and performance. The salient feature of TSDM is that it provides for efficient run-length encoding of constant-intensity segments of a TV picture. Axiomatix has developed a hardware implementation of a highspeed TSDM transmitter and receiver for black-and-white TV or field-sequential color or NTSC format color. The hardware aspects of this TSDM are discussed in the paper also.
    • DISCUSSION OF CLASSICAL AND PUBLIC KEY CRYPTOGRAPHY

      Hershey, John E.; Institute for Telecommunication Sciences (International Foundation for Telemetering, 1982-09)
      Classical and public key cryptography for communications privacy are discussed regarding their relative implementation complexity and overall applicability.
    • DISTRIBUTED CONTROL A CANDIDATE MILITARY COMSAT CONTROL SYSTEM

      MARCHIONDA, PAUL R.; The Aerospace Corporation (International Foundation for Telemetering, 1982-09)
      Advanced Military Satellite Communications Systems providing communications capability supporting projected minimum essential military wartime communications that will accommodate force message distribution, force direction and force report back, and force/force or group-to-group communications. These dedicated communications resources must be continuously available to the wide variety of military users. It is necessary, therefore, that the command/control implementation of these systems be capable of (a) long-term resource allocation to fulfill user requirements with a minimum of delay and system overhead, and (b) insuring system capability to fulfill real-time users service requests. Anticipated operational use indicates that a considerable amount of day-to-day control will be required to coordinate the user access to communications, to provide communications for internal user network control, and to support routine system maintenance activities. This paper discusses a candidate centralized system management and distributed control framework that provides a system operations capability meeting the interconnection requirements needed for such a military type communications satellite system.
    • DMSP BLOCK 5D-2 SPACECRAFT Telemetry Real-Time Analysis and Display System (TRADS)

      Allen, David L.; The Aerospace Corporation (International Foundation for Telemetering, 1982-09)
    • A DROPOUT BASED ERROR CORRECTION METHOD FOR USE ON DENSITY DIGITAL RECORDING SYSTEMS

      Meeks, Leighton A.; Honeywell, Inc. (International Foundation for Telemetering, 1982-09)
      Honeywell has developed and reduced to practice, a variation of the check word approach to error detection and correction for use on multi-track parallel high density digital recording systems. Implemented on the Company’s Model HD-96 systems, this method takes advantage of the high degree of correlation of bit errors with tape signal dropout intervals. A signal dropout detector is provided on the reproduce side for each digital data track to replace the check word at the end of each channel encoding frame. This dropout method has the advantage of reducing buffer memory size required to utilize the check word method. In a previous paper*, the results of a tape signal dropout investigation were reported. In this current paper, details considered critical to successful implementation are described. In addition, sample results from production systems are included.
    • THE EFFECT OF PREMODULATION FILTERS ON BIT ERROR RATE PERFORMANCE

      Bobrek, Pavlo; Sangamo Weston, Schlumberger (International Foundation for Telemetering, 1982-09)
      This paper examines the effect of different types of premodulation filters on the time waveshapes of PCM signals. Using a simplified model of this effect, an expression for the Probability of Error in the presence of Gausian Noise is derived and compared for systems with and without premodulation filtering. A simple single bit decision feedback detector is designed and an evaluation made of its usefulness in improving bit error rate performance using different filters in the presence of different amounts of noise.
    • THE EFFICIENT USE OF A VAX COMPUTER IN THE REAL-TIME TELEMETRY ENVIRONMENT

      Robbins, Robert B.; Data Systems Division (International Foundation for Telemetering, 1982-09)
      The use of a Digital Equipment Corporation VAX computer under the VMS operating system, in a real-time telemetry environment, brings with it many advantages. These advantages pertain to its ability to handle real-time telemetry processing in an efficient and relatively straight forward manner. The author will use the TELSET, TELDAX and TELFOR telemetry software systems as the basis for demonstrating the techniques which have allowed the real-time telemetry user to take advantage of a 32-bit, virtual addressing, architecture.
    • THE ELECTRONIC SWITCHING SPHERICAL ARRAY (ESSA) ANTENNA FOR THE EARTH RADIATION BUDGET SPACECRAFT (ERBS)

      Kudrna, Ken; Hockensmith, Richard P.; Ball Aerospace Systems Division; Goddard Space Flight Center (International Foundation for Telemetering, 1982-09)
      The ESSA is a microprocessor controlled antenna for low orbiting spacecraft for telemetry and command relay through the Tracking and Data Relay Satellite (TDRS) System. The array is a hemispherical shape which is covered with disk radiating elements. A group of radiating elements are continuously selected by the microprocessor controller to form a beam in the direction of a TDRS. A radial switching power divider uses PIN diodes to select the desired radiating elements. The antenna gain is a function of the size of the hemispherical dome. A 30-inch diameter dome is presently being built for the Earth Radiation Budget Spacecraft (ERBS). Gain of this antenna over a hemisphere is 14 dBi and polarization is left hand circular. There are 145 radiating elements with 12 being used at one time to form a beam. The ESSA subsystem weighs 74 pounds and power consumption is 20 watts. R. F. power handling capability is 30 watts. The S-Band radiating elements have a 10 percent bandwidth which allows simultaneous transmission and reception.
    • ELECTRONICALLY STEERABLE SPHERICAL ARRAY CAPABILITIES AND INTERFACES

      Taylor, Taliaferro H.; Ball Aerospace Systems Division (International Foundation for Telemetering, 1982-09)
      For antenna applications which require gains of 7 to 23 dBic over very large solid angle coverage regions, the Electronically Steerable Spherical Array (ESSA) is an antenna which has significant benefits. This paper describes these benefits along with the ESSA’s key performance parameters and its electrical and mechanical interfaces. As extensions of the basic ESSA design, this paper also describes alternate configurations which allow multiple beam operation and integrated packaging of RF electronics. Basically a simple antenna, the ESSA forms its beams by selecting N elements which point in the desired direction. Selection of these elements is performed by a multipole PIN diode switch. This switch sums together the N desired elements from the M elements located on the ESSA’s spherical surface upon receipt of the appropriate commands from the ESSA’s dedicated microprocessor. The ESSA may be either Phase Compensated, or Non-Phase Compensated. In the Phase Compensated ESSA, a 1 or 2 bit phase shifter is used to correct the spherical phase front produced by the array shape. That correction results in higher gain. The most important ESSA benefits are its characteristics of constant phase and gain which are independent of beam pointing angle. These characteristics free the system from the gain and phase perturbations caused by other types of antennas. As a mature technology, the ESSA has been successfully tested with the NASA standard transponder and is presently being fabricated as a 14 dBic gain protoflight unit for a NASA-Goddard Space Flight Center program.
    • FDM-FM COCHANNEL INTERFERENCE IDENTIFICATION SYSTEM

      Chang, Horen; Alvarez, Richard; Lee, Wilfred; Niwa, Kunihiko; Rieger, Frederic J.; Stanford Telecommunications, Inc.; International Telecommunications Satellite Organization; Comsat Laboratories (International Foundation for Telemetering, 1982-09)
      A prototype interference identification system has been developed to detect and identify interfering FDM-FM carriers originating within the INTELSAT* system. Interfering carriers are identified by distinctive code (signature) modulation of the energy-dispersal waveform of each FDM-FM carrier. Identification presently is accomplished within 10 minutes for ratios of interfering carrier power to noise power down to -2 dB, and for ratios of interfering carrier power to desired carrier power down to -17 dB. Possible improvements are discussed for more rapid identification.
    • GALILEO JUPITER PROBE ATMOSPHERE STRUCTURE INSTRUMENT

      Padilla, Jose R.; Martin Marietta Corporation (International Foundation for Telemetering, 1982-09)
      More will be learned about planet Jupiter in the 45-minute Jupiter Probe mission than has been learned in nearly 500 years.
    • GLOBAL DATA COLLECTION VIA THE INTERNATIONAL TELEPHONE NETWORK

      KYRIAXOPOULOS, NICHOLAS; Department of Electrical Engineering and Computer Science The George Washington University (International Foundation for Telemetering, 1982-09)
      An experimental secure, global, data collection system for possible use in international nuclear safeguards has been built and it is undergoing testing and evaluation. The system known by the acronym RECOVER (REmote COntinual VERification), is designed to monitor the operating status of containment and surveillance instrumentation used in nuclear facilities subject to international safeguards. The uniqueness of the design is based on the intended use of the system by an international organization operating as a guest of national entities, with the sensors residing in host facilities while the data collection remains under the control of the international organization. This paper describes the impact of a unique set of technical, economic, political and operational constraints on all aspects of the system design, and it presents the results of an internationally conducted test of the data acquisition features of the system.
    • HUMAN FACTORS IN OPERATIONS DESIGN

      Chafin, Roy L.; Jet Propulsion Laboratory California Institute of Technology (International Foundation for Telemetering, 1982-09)
      There are several underlying factors in the design of an operations organization to control a high technology spacecraft tracking system. The first is the princple of differentiation and integration. The multitude of tasks must be divided so that each individual or team can accomplish assignments without being overloaded. Then, the efforts of all the elements in the organization must be integrated for a consistent attack on the problem of tracking a spacecraft. The differentiation tends to be primarily along technical or functional lines, and by time span, but there are other considerations. The integration is provided by the organization’s coordination and control elements. Operating positions can be designed to be procedurally operated, knowledge operated, or somewhere in-between. “Procedurally operated” means that the operator follows a strict procedure. He does not need to know how the system works, only which procedure to follow. A “knowledge based” operating position means that the operator understands the system sufficiently well to know what to do to accomplish a task. He does not need written procedures. The selection of either procedural based or knowledge based operations influences the operator skill level required, the organization design, and the support required. The system’s uncertainty level, stability level, and complexity are examined to evaluate the level of procedural operation possible.