• The Instrumentation Data Recorder in an Automatic Mode to Record and Reproduce Digital Data

      Nottley, G. C.; THORN-EMI Technology (International Foundation for Telemetering, 1987-10)
      The conventional IRIG Instrumentation Tape Recorder has two major disadvantages when used to record and reproduce digital data. Firstly it has a limited number of discrete tape speeds, and secondly the operator has to calculate and then set the tape speed to give the appropriate packing density or clock rate. The use of microprocessors has made it possible to take the majority of these calculations, and also the setting up of the recorder, out of the users hands. Also the tape speeds available are virtually continuous over the range 17/8 ips to 120 ips. There are other facilities available and this paper describes the operation and facilities of an instrumentation recorder which is almost totally automatic.
    • Parallel Distributed Processing of Realtime Telemetry Data

      Murphy, Donald P.; Syndetix, Inc. (International Foundation for Telemetering, 1987-10)
      An architecture is described for Processing Multiple digital PCM telemetry streams. This architecture is implemented using a collection of Motorola mono-board microprocessor units (MPUs) in a single chassis called an Intermediate Processing Unit (IPU). Multiple IPUs can be integrated using a common input data bus. Each IPU is capable of processing a single PCM digital telemetry stream. Processing, in this context, includes conversion of raw sample count data to engineering units; computation of derived quantities from measurement sample data; calculation of minimum, maximum, average and cyclic [(maximum - minimum)/2] values for both measurement and derived data over a preselected time interval; out-of-limit, dropout and wildpoint detection; strip chart recording of selected data; transmission of both measurement and derived data to a high-speed, large-capacity disk storage subsystem; and transmission of compressed data to the host computer for realtime processing and display. All processing is done in realtime with at most two PCM major frames time latency.
    • Telemetry Formats for the Space Station RF Links

      Marker, Walter; National Aeronautics and Space Administration (International Foundation for Telemetering, 1987-10)
      This paper discusses the formats that have been proposed for the manned Space Station space/ground RF link. In addition to discussing the specific RF formats, the paper seeks to discuss the requirements that have caused the proposed format to exist in its current form. The paper begins by briefly discussing the historical basis for telemetry formats within NASA, and then discusses the unique requirements that the Space Station imposes, compared to traditional space probes. The paper next treats the overall requirements that must be satisfied by the Space Station communications system. Finally the paper discusses the details of the RF format and its proposed operational usage.
    • Voyager Neptune Telemetry: The Voyager Telemetry System

      Madsen, Boyd D.; California Institute Technology (International Foundation for Telemetering, 1987-10)
      Improvements to the Voyager telemetry system, which have been implemented on the spacecraft and in the Deep Space Network (DSN), will allow a net science data return from Neptune essentially equivalent to that received from Saturn in spite of the increased range. Enhancements to the system performance include: Increased DSN ground station G/T, Inter-agency arraying, Spacecraft data compression, Reed-Solomon concatenated coding, Reduced telemetry link uncertainties. Net improvements totaled 8 dB in a system that was state-of-the-art when Voyager was launched in 1979.
    • Expert Systems in Data Acquisition

      McCauley, Bob; Telemetry Systems Operation (International Foundation for Telemetering, 1987-10)
      In an Independent Research and Development (IR&D) effort, the Telemetry Systems Operation (TSO) of Computer Sciences Corporation (CSC) sought to determine the feasibility of using Artificial Intelligence (AI) techniques in a real-time processing environment. Specifically, the use of an expert system to assist in telemetry data acquisition processing was studied. A prototype expert system was implemented with the purpose of monitoring F15 Vertical Short Take Off and Landing (VSTOL) aircraft engine tests in order to predict engine stalls. This prototype expert system was implemented on a Symbolics 3670 symbolic processor using Inference Corporation's Artificial Reasoning Tool (ART) expert system compiler/generator. The Symbolics computer was connected to a Gould/SEL 32/6750 real-time processor using a Flavors, Inc. Bus Link for real-time data transfer.
    • The Real-Time Telemetry Processing System III

      Shelley, Larry R.; Computer Sciences Corporation (International Foundation for Telemetering, 1987-10)
      The Navy's Real-time Telemetry Processing System (RTPS III) is a third generation system. Designed and built by Computer Sciences Corporation (CSC), RTPS III will support the demands of the Navy flight test community well into the 1990's. The RTPS III is custom-crafted using CSC's system development methodology which blends the best features of the current Navy RTPS system and previously proven CSC systems. A major objective of CSC's RTPS III design is the continuation of existing Navy user interfaces. The transition from the existing system to the integrated RTPS III has also been facilitated by the incorporation of common interfaces to Navy applications software, thus ensuring "new system" acceptance. RTPS III is designed to include a powerful front-end capable of Engineering Unit conversions at more than 200,000 samples per second (sps) per telemetry stream with expansion to 500,000 sps. It will include networking concepts which allow the simple addition of additional subsystems should expansion be required. RTPS III also supports both secure and integrated modes of operation for classified and unclassified processing. The CSC design, a custom combination of proven and new development, results in a Navy system which meets tomorrow's flight test requirements today. Other benefits to NATC are a modular, cost-effective solution with lower life-cycle costs, and a broader range of possibilities for evolving and reconfiguring the system to service new applications and users.
    • ReConTTA: A State-Of-The-Art Telemetry Tracking System

      Morton, Stephen G.; United States Air Force (International Foundation for Telemetering, 1987-10)
      The purpose of this paper is to present and discuss key features of a Remotely Controllable Telemetry Tracking Antenna (ReConTTA) system which, truly, represents the current state-of-the-art. The ReConTTA system is planned to support flight testing of all current and future generation aircraft at the Air Force Flight Test Center (AFFTC), Edwards Air Force Base, California. System features to be discussed include: (1) The Antenna Group including Radial Scanning (RADSCAN). (2) The Local Control Group and its interface with the down converting, r-f switching, receiving, diversity combining, and microwave data-link equipment. (3) The Remote Control Group and its interface with microwave and ground station processing equipment. Several examples will be presented, illustrating the capabilities of the ReConTTA system, including the following: (1) Remote control operations utilizing computer control. (2) Broadband frequency coverage from 1435-2400 Mhz. (3) Low tracking angle performance.
    • Advanced Joint Test Assembly (JTA) Telemetry System

      Stimmell, K. G.; Sandia National Laboratory (International Foundation for Telemetering, 1987-10)
      We design telemetry systems which instrument weapons in the Joint DoD/DOE flight test program. These telemetry systems gather data which can be used to determine if a weapon functioned as intended. Traditionally, a telemetry system has been designed to fit the individual requirements of each of the many weapons which have gone into production. The process of defining requirements, designing the system, and getting it into production with the quality assurance demanded of all weapon components takes considerable time, manpower, and money. Due to the rapid advancement of electronics and computer technology, these telemetry systems and their production testers become difficult to support if the weapon service time is extended or if aging test equipment breaks down. We are designing a telemetry system to support new programs for the next decade and to replace old telemetry systems which can no longer be produced. This multi-system Joint Test Assembly (JTA) is being designed to be modular, flexible, and testable. New techniques for increasing reliability, such as redundancy, error detection and correction, and microprocessor recovery will be employed. The requirements for each program can be met by choosing the necessary circuitry from a "shopping list" and packaging to meet the mechanical constraints for each system. Production specifications and test equipment will be in place to support any telemetry which is composed of the previously-designed modules. Modifications of hardware and software to support individual requirements will be kept to a minimum. We expect this new approach to telemetry system development to significantly reduce cost and lead time for every program on which it is employed. The use of this telemetry system on multiple programs should also enhance reliability.
    • Accommodating Telemetry Data Acquisition Systems

      Shelley, Larry; McCauley, Bob; Computer Sciences Corporation (International Foundation for Telemetering, 1987-10)
      The Telemetry Systems Operation (TSO) of CSC in Lompoc, California, has been developing telemetry systems since October 1981. Three major turnkey systems have been developed as well as several smaller derivative systems. Each system, built for a different end-user, was custom fit to support unique requirements and often represented several different techniques for accommodating similar problems within different system architectures. This paper describes the evolution of TM system architectures developed by TSO Lompoc, and the special engineering problems solved in the course of their development to provide the user with accommodating telemetry systems that are responsive, expandable, and cost-effective.
    • Data Acquisition & Recording System

      Gustin, Thomas W.; Systems Research Laboratories, Inc. (International Foundation for Telemetering, 1987-10)
      The Data Acquisition & Recording System (DARS) is a totally self-contained, high technology data conversion and acquisition system, especially designed for unconstrained and hostile test environments. This system's initial use is for the Advanced Dynamic Anthropomorphic Manikin (ADAM), a test article for acquiring physical event and performance information from both the fully instrumented manikin which contains this system, and from the advanced technology CREST ejection seat upon which it rides. The ADAM development program was sponsored by the Air Force's Aeronautical Systems Division, Life Support Systems Program Office, and the Armstrong Aerospace Medical Research Laboratory. This paper presents the system level design of the DARS with emphasis on techniques used to solve special applications problems including survival in high 'G' tests, high speed computer controlled acquisition activities emulating PCM functions, simultaneous Telemetry and onboard data storage techniques, special sensing techniques, and a custom generic signal conditioning front end system. The presentation will conclude with several types of test environments and scenarios chosen to demonstrate the capabilities of the DARS, including the ADAM application.
    • The Possibility and Prospect of Adopting New Multiplexing Techniques in Telemetering

      Chang, Jiang; Beijing Institute of Satellite Information Engineering (International Foundation for Telemetering, 1987-10)
      Ordinarily, in telemetering systems people use FDM and TDM techniques for transmitting various signals from a great number of transducers. But neither in FDM nor in TDM there always exist some shortcomings, such as inter-modulation interference, oversampling, low efficiency of channel utilization and troubles in synchronization. In recent fifteen years, many new multiplexing techniques are proposed due to the development of satellite communications, such as multiple carrier system in DCP, which is often used in geostationary meteosat for collecting environment parameters of the earth surface, SCPC, SPADE and code division multiplexing by m-sequences, GOLD sequence, frequency hopping, Waith functions. In this paper, from the standpoint of telemetry, we discuss and compare the advantages and drawbacks of these methods in bandwidth utilization, capacity, interference, and the ratio between performance and cost when they will be used in telemetry.
    • Telemetry Bus Linkage with a High-Speed Ring Architecture: An Approach Analysis

      Nicolo, John M.; Aydin Monitor Systems (International Foundation for Telemetering, 1987-10)
      The growing complexity of space vehicle, aircraft, and missile test data analysis requiring larger data volumes and higher data rates, in conjunction with real-time analysis and display, calls for a new approach in telemetry system bus architecture. To meet these needs AMS developed the Mercury Bus, and a high-speed ring architecture capable of linking up to 7 Mercury Busses together without reducing targeted bus bandwidth of 6 MWPS. The Mercury Bus is a 48 bit parallel bus consisting of 32 data bits, and 16 "token" or address bits. It supports setup or real-time transfers between multiple master/slave modules within a chassis. The ring architecture consists of Bus Arbitrator, Repeater, Terminator Modules (BAT's) connected together by circular unidirectional read and write pipelines. The BAT arbitrates bus mastership, repeat's intra-chassis transfers and provides signal termination for the Mercury Bus. The pipelines relay bus transfers to successive chassis within the ring. This architecture currently supports up to 7 chassis or 112 modules per system. The ring architecture has met and exceeds initial design criteria with transfer rates measured in excess of 8 million words-per-second. It performs sustained high-rate data transfers while maintaining the data integrity and reliability associated with real-time telemetry. This architecture is well suited for systems with multiple input streams and high data processing requirements. Overall performance is attributed to the low noise characteristics of a controlled impedance backplane; implementation of module front end standardized bus interfaces; and the Bus Arbitrator, Repeater, Terminator module.
    • Recent Advance in Instrumentation Recording Technology in China

      Xinnong, Zhang; Beijing Research Institute of Telemetry (International Foundation for Telemetering, 1987-10)
      In this paper the YJ2-4 portable tape recorder, which was recently developed by Beijing Research Institute of Telemetry, is described, and some of its major design features are discussed. YJ2-4 is a high performance, wideband, and microcomputerbased recorder/reproducer system, and compatible with existing international standards in the field of instrumentation tape recording (ISO 6068-1985 and IRIG 106-86).
    • A Technical Comparison of Frequency and Phase Modulation Relative to PCM Data Transmission Systems

      Lovejoy, David; Physical Science Laboratory (NMSU) (International Foundation for Telemetering, 1987-10)
      Direct experience in the design and developement of airborne telemetry systems utilizing both principles of modulation. System level analysis of receiver phase coherency, bit sync error codes, data band width, transmission efficiency and overall system complexity. High reliability, miniaturized packaging and HI-G survivability will be stressed as well as illustrated.
    • Voyager-Neptune Telemetry: The DSN 70 Meter Antenna Upgrade

      Hall, Justin R.; McClure, Donald H.; California Institute Technology (International Foundation for Telemetering, 1987-10)
      The Deep Space Network is responsible for the acquisition of in-situ science and engineering measurements and navigation data from spacecraft whose missions are to explore the Solar System. It must respond to new opportunities in the mission set supported so as to maintain or enhance mission science value. The large capital investment in such a Network mandates an evolutionary design approach wherein upgrades can be effected at low cost, and if appropriate, on existing capability. The 64-Meter antenna design, completed in 1963, is an example of this approach, in that it has permitted a relatively low-cost upgrade which increases performance significantly. The technology assessment was completed in 1975, and the option was exercised in 1986, when needed. Several key characteristics of the DSN design approach, the costs to upgrade performance over the past several decades, and some fundamental constraints on performance are discussed. Finally, the specific 70-Meter upgrade task and resulting overall benefits to Voyager-Neptune and the mission set are summarized.
    • Effects of Co-Channel Interference with Frequency Offset on PSK Signals

      Raghavan, Srini; The Aerospace Corporation (International Foundation for Telemetering, 1987-10)
      The sharing of C-band between microwave terrestrial and satellite communication systems invariably introduces interference from one system into the other. Such co-channel interference becomes even more important in satellite receive stations with smaller antennas and must be minimized to achieve system performance objectives. In this paper, co-channel interference due to two TD2 (FDM/FM) carriers into a satellite receive system, receiving binary phase-shift keyed (BPSK) signal, is considered. It is shown that the frequency offset of the TD2 carriers from the BPSK carrier can be used to minimize co-channel interference effects. Equations are given which compute the bit error rate (BER) of BPSK signals in the presence of an interfering unmodulated carrier. They are followed by some results due to TD2 carrier interference.
    • Real Time Digital Strip Chart Emulation

      Halsey, Tim; Brimbal, Michel; Grottenthaler, Gary; Gould Incorporated (International Foundation for Telemetering, 1987-10)
      The efficiency of range telemetry as currently practiced is somewhat limited by the display technology employed. The manpower, space, and accuracy problems associated with current methodology are examined. The limitations of some new approaches are discussed. The concept of Real Time Digital Strip Chart Emulation (RTDSCE) and the benefits inherent to such a technical approach are presented and discussed in detail. These benefits include reduction of manpower and space requirements by the use of the workstation concept, the elimination of D/A conversion by direct recording of digitized signals, and the facilitation of critical realtime viewing through high resolution video monitoring.
    • Interagency Arraying

      Cox, Henry G.; California Institute Technology (International Foundation for Telemetering, 1987-10)
      Voyager ground aperture requirements for Neptune encounter in August 1989 exceed the expected capabilities of the Jet Propulsion Laboratory's Deep Space Network (DSN) 70- and 34-meter antennas. Agreements have been consummated with the National Science Foundation to array the National Radio Astronomy Observatory's Very Large Array in New Mexico and with the Commonwealth Scientific and Industrial Research Organization's Parkes Radio Telescope in Australia with the DSN. This technique, which was demonstrated during Voyager's Uranus encounter, will provide a greater return of imaging and non-imaging science data. The arrays consist of the normal facility receiving equipment at each location, augmented by special receiving, combining, recording, and monitor and control equipment. This equipment has been designed, is being implemented, and will be operated during the Neptune encounter to effectively double the available antenna aperture over the western United States and Australia.
    • An Efficient Decoding Algorithm for Long Convolutional Codes

      Ng, Wai-Hung; Hsieh, Ning-Ning; The Aerospace Corporation (International Foundation for Telemetering, 1987-10)
      Optimum decoding of long convolutional codes is an attractive technique to achieve reliability of communication. However, conventional decoding algorithms are very sensitive to variations in operational conditions, and such algorithms are also difficult to adapt to high-data-rate systems. Based on distance properties of code and pattern analysis of test-error sequences, a new decoding algorithm is derived that does not have those disadvantages.
    • An Implementation of Concatenated Coding Scheme on Indian Spacecraft

      Martin, Kamalini; Seshaiah, R.; Vasantha, E.; Rajangam, R. K.; ISRO Satellite Centre (International Foundation for Telemetering, 1987-10)
      A Concatenated Coding Scheme to provide an extremely 'clean' channel is suggested for onboard spacecraft telemetry system by the Consultative Committee for Space Data Systems (CCSDS). The outer code is a Reed Solomon block code and the inner, a Viterbi or Convolutional Code. The Gaussian channel are corrected by the inner code. However, the Viterbi decoder may introduce some burst errors. These are then corrected by the Reed Solomon decoder. The inner Viterbi code (K=7, rate 1/2) was developed and implemented for the first time in RSD2 (Rohini series) satellite. The outer code has not yet been implemented onboard spacecraft since the decoder has not been fully developed. However, the onboard encoding system (255,223) has been developed and tested. This paper describes the development and implementation of Viterbi encoder in RSD2 satellite along with its inorbit performance.