The International Telemetering Conference/USA (ITC/USA) is dedicated to the promotion and stimulation of technical growth in telemetering and its allied arts and sciences. It is the premier annual forum and technical exhibition providing telemetry specific short courses, technical papers from professionals and students, and exhibits of the industry’s leading companies. ITC/USA is sponsored by the International Foundation for Telemetering (IFT), a non-profit corporation dedicated to serving the technical and professional interests of the telemetering community.

This collection contains the proceedings of the twenty-second International Telemetering Conference, October 13-16, 1986. The conference, sponsored by the International Foundation for Telemetering, was held at the Riviera Hotel in Las Vegas, Nevada.


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  • International Telemetering Conference Proceedings, Volume 22 (1986)

    International Foundation for Telemetering, 1986-10

    Krishen, Kumar; Erwin, Harry O.; Johnson Space Center (International Foundation for Telemetering, 1986-10)
    This paper presents a review of the ranging and tracking systems/techniques used in the past NASA programs. A review of the anticipated requirements for future rendezvous and docking operations is also presented as rationale for further development of the technology in this area. The first American rendezvous in space was between Gemini VI-A and Gemini VII and took place on December 15, 1965. The Gemini vehicles were equipped with a noncoherent pulse radar. The target vehicle carried a transponder to assist the radar in target acquisition. Angle tracking was accomplished by the phase-comparison monopulse technique. In the Gemini, Apollo, and Skylab programs, the rendezvous and/or docking were manual operations supported by radar measurements and visual observations. The Shuttle rendezvous radar is a Ku-band, pulse-Doppler radar which doubles as a communications transceiver. This radar is not accurate enough to support close-in stationkeeping or docking. An automatic soft-docking capability has been established as a requirement for future space operations. Millimeter wave and laser radar systems have shown promise in satisfying the needed accuracy requirements and size constraints (for space applications) compared to the microwave systems for proximity attitude, position and velocity measurements. A review of these systems and their capabilities is presented in this paper. Rather than developing a separate sensor to satisfy the requirements of each new spacecraft, a hybrid design is proposed for a versatile system which can satisfy the needs for different spacecrafts and missions.

    Turner, William C.; Electro-Magnetic Processes, Inc. (International Foundation for Telemetering, 1986-10)
    Performance data taken on three candidate telemetry tracking antennas which employ significantly different beam scanning principles are presented. Measurements of antenna feed-induced phase noise were made at S-Band and compared.

    Evans, Alan G.; Naval Surface Weapons Center (International Foundation for Telemetering, 1986-10)
    The TI 4100 Geodetic Global Positioning System (GPS) Receiver has been field tested in several environments. These include collocation rooftop tests near reflective equipment, isolated desert positioning tests, and shipboard survey tests. The receiver data consisted of pseudorange (code) and biased Doppler range (phase) measurements on both L1 and L2 frequency channels. This paper compares differences between ionospherically corrected pseudorange and biased Doppler range measurements to demonstrate the significant effects of signal multipath on the pseudorange measurements. That is, pseudorange signal multipath effects can be isolated, detected, and statistically modeled using only the above measurements. Examples are given for various receiver antenna locations. Day-to-day comparisons are made to demonstrate the repeated multipath effects due to repeated satellite-to-antenna geometries. The results can be used to analyze and statistically model pseudorange multipath effects for possible improved positioning and GPS satellite orbit determination accuracy.

    McConnell, John B.; Baker, Robert L.; Flowers, Harold; Western Space and Missile Center; ITT-Federal Electric Corporation (International Foundation for Telemetering, 1986-10)
    The Western Space and Missile Center (WSMC) plans to precisely synchronize remote instrumentation site timing on the Western Test Range (WTR) using Global Positioning System (GPS) equipment being developed for Tri-Service range applications. This paper describes background information, current WTR timing capability, remote site synchronization requirements, a proposed GPS timing system configuration, and testing approach.

    Sargeant, H.; Interstate Electronics Corporation (International Foundation for Telemetering, 1986-10)
    Predetection recording of spread-spectrum (SS) signals such as GPS transmissions is a desirable objective for both users and developers of equipment designed to receive such signals. (GPS user-equipment development is a lengthy process during which signal simulators are only partially useful.) Upon playback, GPS signals are used by the same or modified receivers so that acquisition, processing, detection and tracking loops can be altered to optimize the receiver parameters. Development of predetect SS signal recording systems is difficult to achieve in practice. Such systems not only must be of suitable phase linearity to preserve the signal content to be extracted but sometimes must also preserve the exact signal-to-noise ratio (SNR) characteristics of the recorded signals. Existing conventional test equipment is unsuitable for deriving value judgments of the quality of a predetect recording system’s output because the SS signal has a negative SNR. This paper reveals that it is possible to use, for this purpose, tape recorders now available on many test ranges in combination with auxiliary equipment similar to that designed for the U.S. Navy’s TRIDENT Program (recording C/A-code data from in-flight missile translators). The basic techniques are described in some detail to enable potential users to understand the necessary equipment concepts and evaluate the author’s approach in terms of their own applications.

    McConnell, John B.; Hoefener, Carl E.; Western Space and Missile Center; Interstate Electronics Corporation (International Foundation for Telemetering, 1986-10)
    The NAVSTAR Global Positioning System (GPS) allows extremely accurate global determination of time as well as position and velocity. Currently, the DoD test and training ranges of the United States are working towards using GPS to obtain position and velocity information and recently attention has been given to using GPS for precise range timing. This paper provides background information, discusses the advantages of using GPS for range timing, and describes two timing system configurations using Tri-Service GPS range equipment.

    Hoefener, Carl E.; Wells, Lawrence; Interstate Electronics Corporation (International Foundation for Telemetering, 1986-10)
    GPS will provide a very attractive means to track kinetic energy weapons in space for the Strategic Defense Initiative programs for system test and evaluation. However, the small size and very high dynamics of these vehicles complicate the use of GPS. This paper considers these issues and suggests a solution.

    Wait, D. F.; Baird, R. C.; Daywitt, W. C.; Newell, A. C.; Perera, S.; Repjar, A. G.; CyberLink Corporation (International Foundation for Telemetering, 1986-10)
    The National Bureau of Standards (NBS) has investigated the calibration and measurement support requirements of millimeter wave satellite systems such as MILSTAR. Essentially three new measurement problems arise because of operating in the upper SHF and EHF frequency ranges. First, without adequate methods to measure the atmospheric loss, the accuracy of EIRP measurements in the 20 GHz to 45 GHz range can be no better than 0.5 dB to 3 dB (depending on frequency and antenna elevation angle). The atmosphere absorbs and scatters radiation traveling through it, both reducing the magnitude of and depolarizing a received signal. Second, standards, measurement support services, and some measurement techniques are not presently available from NBS and they are needed to support millimeter wave antenna gain and thermal noise measurements. Of special concern are the effects of connectors and adapters, since they can introduce significant errors into mm-wave measurements. Theird, if the sun and/or moon are to be used for measuring earth terminal G/T, earth terminal antenna gain, or satellite effective isotropic radiated power in the millimeter region, they need to be appropriately characterized at those frequencies. The sun and moon are only useful as measurement sources for antenna systems with gains less than about 50 dB, but most MILSTAR systems are expected to fall in this category.

    Bustelo, Richard A.; Harris Corporation (International Foundation for Telemetering, 1986-10)
    The Global Positioning System Ground Antenna is an unmanned earth terminal providing TT&C functions for the constellation of GPS satellites. This paper describes the design of the GPS/GA, with emphasis on those design issues unique to unmanned terminals. The primary contribution of trained operators is contingency management and mission flexibility. The real challenge in design of an unmanned terminal is not automating the processes, but providing the ability to handle off-nominal situations, equipment failures, and new mission scenarios. Design philosophy of the architectural, communications and contingency management features of the GPS/GA are discussed. System performance and mission flexibility in off-nominal situations are related to operational aspects of a typical manned terminal. Operational experience with the GPS/GA provides further insight into the critical design issues of unmanned terminals.

    Kurisu, Kurtis Lee; Aerospace Corporation (International Foundation for Telemetering, 1986-10)
    The Space-Ground-Link-Subsystem (SGLS) has been providing Telemetry, Tracking, and Commanding (TT&C) services to the Air Force Satellite Control Facility (SCF) since the late 1960’s. The current transmitter system is comprised of a 10 kW travelling wave tube (TWT) and associated equipment. As solid state technology matures, it is now appropriate to consider alternative approaches. Solid state offers the potential advantages of improved reliability, graceful degradation, high efficiency, and lower life cycle costs. This paper addresses the current status of solid state multi-kilowatt systems development. The present state of solid state power transistors and low loss power combiners are at a stage where high power S-band CW transmitters are possible. The advantages and disadvantages of the state of the technology are discussed as are the practical considerations for integration into SGLS systems applications.

    Skinner, Patrick J.; Ford Aerospace & Communications Corporation (International Foundation for Telemetering, 1986-10)
    Modernizing labor intensive Remote Tracking Stations (RTS), increasing individual station capacity, and providing interoperable links between three separate Air Force satellite networks are the objectives of the Automated RTS (ARTS) program now half way to completion.

    Garas, Anthony G.; Sperry Corporation (International Foundation for Telemetering, 1986-10)
    Significant advances in processing power and hardware miniaturization for aerospace applications has led to new distributed avionics architectures. These architectures have driven system data transmission requirements to the point where current data communications and interconnect technologies are marginal or inadequate. Advanced spacecraft including Space Station and SDI platforms have identified the need for distributed processing and real time control, requiring large and complex data communications networks with bus data rates in the 100 to 500 MBPS range. To address this need a new communications protocol has been developed to provide high data rate and very short transport delay performance. The protocol is implemented using a star topology fiber optic data bus. During the design of this system for spacecraft data bus applications, particular attention was paid to system robustness, redundancy, fault tolerance, autonomy, and error control. The salient system design, hardware configuration, and performance of an eight node demonstration network jointly developed by NASA Goddard and Sperry Corporation are presented in this paper.

    Krause, Lloyd O.; Reyes-Nieves, Carlos; Frazier, Ivor; Satellite Systems Division (International Foundation for Telemetering, 1986-10)
    DPSK modulation and demodulation are usually based on logical selection of the difference phase before modulation and the recovery sum phase after detection. Here, we describe an analogue procedure done directly on the PSK’d I-F. BAW delay elements are used in arrangements of feed-forward for difference modulation and of feedback for demodulation. Characteristics are described, and results of laboratory implementation tests for data rate and carrier frequency variations are given. An I-F of 60 MHz and a bit rate of 200 kHz were used as nominal values. Robust performance is indicated.

    Caprio, James R.; Nystrom, Lennart; Comptek Research; Anaren Microwave (International Foundation for Telemetering, 1986-10)
    A digital frequency discriminator (DFD) of the delay-correlator type is described. The device is shown to have an instantaneous frequency measurement capability on very short pulses. The theoretical performance of the DFD in a noisy background is derived and shown to compare favorably with measured results.

    Lal, P.M.C.; Palsule, V.S.; Kumar, Pramod; Indian Space Research Organization (International Foundation for Telemetering, 1986-10)
    Spread Spectrum Systems have the potential of sharing the frequency spectrum with broadcasting, telephony and data communications services due to their low power density signalling. The study of feasibility of co-existence of Direct Sequence Spread Spectrum ranging signal with TV or SCPC carriers in a common satellite transponder is presented in this paper. The suitability of this type of ranging for Indian National Satellite-IB (INSAT-IB) system from Master Control Facility (MCF), Hassan, India has been examined. The mutual interference effects between spread spectrum ranging signal and TV or SCPC services through various sizes of earth stations in INSAT network have been calculated. The study indicates that simultaneous accurate range measurement by spread spectrum technique from control earth station is possible without any significant degradation in signal quality of TV or SCPC services.

    Wood, Tracy G.; Ampex Corporation (International Foundation for Telemetering, 1986-10)
    The advent of the D-1 cassette standard will have a profound impact upon the instrumentation tape recording industry starting in about 1990. Under the auspices of the Society of Motion Picture and Television Engineers (SMPTE) and the European Broadcast Union (EBU), broadcasters, media manufacturers and television recorder manufacturers have developed a series of standards governing digital recording of television signals using a set of standard, high-quality cassettes. To support television applications, two specific formats are necessary to cover the marketplace; a “component” format, which is independent of the television standard and compatible with a digital studio, and a “composite” format which is dependent upon the national format and is compatible with analog studios found today. Standards are in place covering 4:2:2 digital component recording. Proposals covering composite digital recording formats are now being discussed in the industry. As the only U.S. recorder manufacturer with a declared intent to manufacture hardware for the television industry to these standards, Ampex has participated in the generation of these standards. This paper will discuss the cassette and data standards which have been created for the television industry. Where deficiencies and limitations in those standards exist for data recording, these will be pointed out.

    Beffa, James C.; Ishii, T. Koryu; Marquette University (International Foundation for Telemetering, 1986-10)
    A millimeter wave radio responder was evaluated as a remote sensor of surface conductivity and laser light intensity. A 10 mm CdSe photocell was illuminated by a 1/4 mW, 632.8 nm He-Ne laser light. The photocell was not connected to anywhere. The terminals were left open. The photocell was interrogated by a remotely placed millimeter wave radio responder operated with the frequency of 69.6 GHz and the transmitter power of 3 mW. The millimeter wave radio responder was able to sense the radio echo from the surface of the photocell. The laser illuminated area on the photocell was only 2.86% of the entire active area, yet the radio responder output showed up to 15 dB difference between the laser spot on and off from the target. The minimum reflected signal change observed was 0.002 dB by tilting the target 20 degrees from the normal incidence of the millimeterwave beam. This was translated to be 0.025% of surface conductance change on the target. This remote sensing was done using an instrumentation of the sensitivity of !40 dBm. Thus, the usefulness and advantage of employing a millimeter wave radio responder for remote sensing of minute change in the surface conductivity and/or the laser light intensity have been demonstrated in this research.

    Jeske, Harold O.; Sandia National Laboratories (International Foundation for Telemetering, 1986-10)
    In Frequency Division Multiplex (FDM) systems, nonlinearities in the modulation and demodulation processes of the transmission system produce intermodulation (IM) products which are effectively added to the desired modulation. The effect of these added products is the degradation of data accuracy in the form of noise on the subcarrier data. Currently there are no standard test procedures or specifications that permit the prediction of the level of these IM products during system design. The characterization of transmitter modulation linearity by the measurement of IM, or cross-products, produced by simultaneous modulation by two tones, is considered ideal. This is because the test conditions can closely simulate the highest modulation level subcarriers used and the necessary demodulation equipment can he readily calibrated using common frequency modulated sources. The modulation tones used are both in the upper portion of the transmission system’s baseband and at a modulation level near the level of intended use. Measurement of only the difference frequency IM component, (f !f ), is considered 2 1 adequate for the determination of 2nd order nonlinearities. The 3rd order IM components are measured only at (2f !f ) and (2f !f ) and are normally found to be of equal 1 2 2 1 amplitudes with FM transmitters. All higher order products, as well as direct harmonics, are ignored. From the three IM level measurements, and the two desired tones, the 2nd and 3rd order modulation intercept points (IP and IP ) are determined in essentially the 2 3 same manner as the intercept point, or IP, that is common in specifying the linearity of broadband RF amplifiers. When the amplitude of the various signal and IM components are plotted on log-log scales, the desired signals have a slope of one while the 2nd and 3rd order products have slopes of two and three respectively. On log-log plots the intercept point is the modulation level at which extensions of the low level values of the IM components meet the extension of the desired modulation level. Once the IP values are determined, they may be readily used for system IM calculations. Measured IM levels in a sixteen channel FDM system compared very favorably with predicted levels using the IP values obtained from two-tone tests. The nonlinearities of the demodulator employed in the test system may be evaluated by the use of the “beat” frequency of two independently modulated FM signal sources as the required input to the demodulator. The IM products in the demodulator output in this case are due only to the demodulator’s transfer characteristics. IM product levels of the test system greater than 60 dB below the simultaneous modulation level of ±300 kHz each by 400 and 450 kHz tones are obtained at Sandia Laboratories. The use of two-tone IM tests for the evaluation and specification of FM transmitter modulation linearity is strongly recommended.

    DAHAN, MICHAEL; LOD ISRAEL (International Foundation for Telemetering, 1986-10)
    This paper describes an on-board PCM data acquisition and processing system using standard PCM units and commercial micro-computer equipments. A special interface, which was developed in order to allow a direct connection to PCM encoders, is also presented. It performs data buffering and decommutation prior to the data acquisition process. This approach facilitated the independent conduction of flight tests away from the users’ ground stations using a minimal investment. It helped to provide test results in flight or immediately after flights, thus shortening the flight test processing turn around time and contributing to expedite the overall flight test program.

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