• Data Compression Using the Fast Fourier Transform

      Maschhoff, Robert H.; Lee, Kyong H.; Gulton Data Systems (International Foundation for Telemetering, 1988-10)
      The Fast Fourier Transform (FFT) technique has long been used for spectral analysis but it has not been fully exploited for data compression purposes. This paper presents the concept for compressing telemetry data using the FFT in such a manner that the time domain waveform can be recovered. The sampled time-domain data is transformed into the frequency-domain data and only the significant components are selected and transmitted. Actual flight data is used to simulate the data compression performance. Some comparisons are made between this FFT approach and other possibilities.
    • Data Handling and Processing as Applied to White Sands Missile Range

      Kelley, A. L.; Malone, C. P.; Fairchild Weston Systems Inc.; White Sands Missile Range (International Foundation for Telemetering, 1988-10)
      Today's large missile testing ranges are demanding sophisticated processing and displays of telemetry data for real-time decisions. These present-day requirements created a need for better data handling and processing than those of the past. These requirements are driven by higher data rates, more complex formats, and increased real-time decision making (i.e., flight safety area). White Sands Missile Range's (WSMR's) initial real-time Telemetry Data Processing System was provided by IBM in 1969. This system was augmented several times by adding higher-speed telemetry front ends and preprocessors. However, this was not adequate to keep pace with requirements for data processing and display at WSMR. Presently, WSMR has Fairchild Weston Systems, Inc. (FWSI) under contract for a new Telemetry Data Handling System. This FWSI system will support WSMR's anticipated demands for now, for the next decade's planned growth, and beyond. This paper defines data-handling tasks at WSMR, explains how these tasks were handled in the past, and how they are presently handled. Next, the new system is described explaining how it fits into WSMR's present and future plans; and how it provides all the telemetry data handling, storage, processing, and display capabilities to support these tasks. Both hardware and software are discussed for this totally turn-key operating system.
    • Data System Overview

      Karhr, Joseph R.; Jet Propulsion Laboratory/California Institute of Technology (International Foundation for Telemetering, 1988-10)
      The design of the SFOC data system is based on a "design for change" philosophy. It emphasizes standards throughout the implementation, allowing for reuse of software, for periodic changeout of hardware, and for an evolving network configuration. Commercial off-the-shelf hardware and software components are incorporated in a way that avoids dependencies on any single vendor. Multiple flight projects are supported by building upon the baseline system with a minimum of special purpose adaptations. In addition to the multi-mission aspect of SFOC, it must also satisfy multiple users representing multiple disciplines. Data system operators monitor and control SFOC itself. Spacecraft team members keep a vigil to protect the health of the spacecraft. Mission planners and sequence designers control the spacecraft. Science investigators remotely calibrate and control their onboard instruments. SFOC provides near-realtime and nonrealtime support to end-users for downlink (telemetry) and uplink (command) functions. This paper provides an overview to the design of the overall SFOC system and describes the implementation of the current baseline SFOC. It summarizes the important design decisions that have been made, and explains the approach taken to meeting these challenging requirements.
    • Data Transport Subsystem: The SFOC Glue

      Parr, Stephen J.; California Institute of Technology (International Foundation for Telemetering, 1988-10)
      The Data Transport Subsystem (DTS) is a core subsystem of SFOC which holds together the GIFs, TISes, DMDs, DTVs and other SFOC application subsystems allowing them to operate in a distributed LAN based workstation environment. DTS does this by providing two primary features. The first feature is transparent local and remote interprocess communication. The communications interface is identical between two application subsystem processes whether they're running in the same machine or different machines. The second feature is the Logical Name Server, which makes connections on a name basis without regard to location or network topology. With these two features SFOC becomes a distributed system. Processes within a subsystem can even be distributed to perform load leveling and enhance system performance. Distribution fosters the use of redundancy and hot backups by allowing nodes to serve multiple purposes. Distribution allows isolation of mission telemetry while providing shared use of a common database. It supports the SFOC goal of off-the-shelf hardware expansion and upgrade. DTS provides an open-close-send-receive model of interprocess communication. It offers three types of service: virtual circuit, datagram and broadcast. The virtual circuit service supplies a full duplex path between communication endpoints and guarantees data integrity. The datagram service allows many communications endpoints to send to one endpoint. This is useful for sending status to a central process. The broadcast service allows a process to send to many receiver endpoints. This can be used for continuous monitoring of telemetry streams by multiple processes.
    • Decommutation of Mil-Std 1553B Data from EA6B or IRIG Telemetry Formats

      Devlin, Steve; Aydin Monitor Systems (International Foundation for Telemetering, 1988-10)
      With the acceptance of Mil-Std-1553B by vehicle and weapons industries a wealth of new information is available for vehicle testing. In the past, selected data was extracted and included in a standard PCM telemetry stream. But only the selected data was made available. In EA6B and in the proposed IRIG Standard, multiple Mil-Std-1553B data busses are combined with identifying control bits in a single PCM telemetry stream. All of the information traveling each bus is available to the ground station. These formats share a number of features. One is that for each Bus the Mil-Std-1553B word appears in the same order in the telemetry stream. Another is that individual data words do not depend on their position in the telemetry stream for identification, but they do depend on the control information associated with the current message to give meaning to the data words. An efficient approach is outlined for identifying, selecting and routing individual measurements, messages, and/or all Mil-Std-1553B bus information to processes and I/O devices in a data flow environment.
    • Design of Space Station Era Mass Storage Systems

      Homer, Ward P.; Chesney, James R.; NASA, Goddard Space Flight Center (International Foundation for Telemetering, 1988-10)
      Mass storage systems used in the Space Station era must be able to store, retrieve, process, and distribute data, in near real time, at rates up to 300 Mbps and with fast access storage greater than one terabit. To meet NASA's required speed, capacity, flexibility, and reliability at a reasonable cost, these systems will need to employ modem techniques of data presorting, disk stripping, and parallel redundancy. These systems will, also, have to include special, NASA specific subsystems which pre-process telemetry data in order to reduce direct CPU loading and overall system complexity. Commercial storage systems and components available today do provide the fundamental elements required for the development of such a high performance mass storage system. In particular, new commercial parallel drive array systems and parallel drive controllers provide an opportunity to develop and prototype architectures which are suitable and cost effective for NASA's applications. In addition, by utilizing experienced already gained in the use and application of VLSI technology, various required NASA specific functions can be integrated with these commercial storage components to develop an intelligent mass storage system prototype. This paper describes the architecture, components, and technical approach for such a mass storage system prototype.
    • Designing and Reliability Assessment to Fault-Tolerant Telemetry Systems

      Ji-San, Lu; Beijing Institute of Special Mechanical and Electrical Devices (International Foundation for Telemetering, 1988-10)
      In the areas of space technique, It is required that telemetering systems have higher reliability then the observied monitor systems. However, the reliability of telemetering systems themselves are generally lower then that of required. For this reason, this paper discusses the necessity of designing Fault-Tolerent Telemetering Systems, and the main methods to improve the reliability of Non-Fault-Tolerant Telemetering Systems. This paper also discusses the objective, principle, methods to designing Fault-Tolerant Systems, and presented the analysis results of reliability assessment
    • Digital Color TV Telemetry

      Schaphorst, Richard A.; Comeau, Charles P.; Delta Information Systems, Inc. (International Foundation for Telemetering, 1988-10)
      In most of the initial applications of digital TV telemetry the video source signal is monochrome (typically RS-170 standard). However color TV is now employed extensively in many of the government test ranges, and it is likely that it will be required to digitally transmit the NTSC color TV signal for security and other reasons. It is also likely that the bit rates which will be employed for this transmission will range from 1 to 20 mbps depending upon the application. This paper presents the general issues involved in digitizing color TV signals, describes alternative color coding techniques, compares these alternatives, and describes one particularly promising approach in detail. Alternative coding techniques that will be discussed and analyzed include direct coding of the composite NTSC signal as well as several component coding concepts - Y, I, Q; Y, R-Y, B-Y; and the transmission of chroma lines on an alternating basis. Specific techniques for multiplexing the digitized color component signals will be presented. It is desirable that the color coding technique be an incremental expansion relative to existing monochrome coding concepts. One particular technique which shows promise of meeting this objective is presented and discussed.
    • Digital Microwave System Mobile, All-Terrain System for Telemetry or Communications

      Strom, Robert L.; Emmenegger, J. M. (Hans); Boeing Aerospace Company; Broadcast Microwave Services, Inc. (International Foundation for Telemetering, 1988-10)
      Portable, mobile tactical microwave telemetry and/or communications systems have always been plagued with three major problems: antenna height for first fresnel zone clearance over the terrain between the two ends of the link, atmospheric multipath fading and multipath reflections from buildings, bodies of water, certain terrain features, etc. This paper describes a digital microwave system with a modular capability to add additional digital channels, analog channels or voice channels as required. A modular Baseband Processor is used, which provides multiplexing capability and modulation of high speed digital data at a bandwidth of one bit per Hz using the Duobinary Technique which also provides error detection capability without the need for adding extra bits to the stream.
    • A Digital Video Link for Telemetry Applications

      Ottesen, Cory W.; Sandia National Laboratories (International Foundation for Telemetering, 1988-10)
      Using a simple, yet flexible, pixel compressor and a frame buffer, a compact digital video link has been built which allows a trade-off between bit rate, spatial resolution, and frame rate.
    • Distributed, Real-Time, High-Resolution Color Graphics Display System for Telemetry

      Querido, Robert; Friedman, Paul J.; Loral Instrumentation (International Foundation for Telemetering, 1988-10)
      Dramatic increases in telemetry data rates and sources require test engineers to view and digest real-time data in order to make cogent decisions about whether to continue or modify flight tests. Traditional telemetry systems offer limited insight through a myriad of strip charts and alphanumeric displays. Attempts to improve this human interface employed expensive central superminicomputers and display systems. Although these methods have been successful, development and procurement costs and delays have limited their deployment. Recent advances in low-cost standard display, processing, and network technology have led to the development of the System 500. The System 500 employs a distributed architecture. Independent, relatively low cost, high-resolution color graphics workstations connect to the data acquisition and processing subsystems via Ethernet.* Each station is independent, requesting and then receiving only data for display. The combined ability to physically display and update only a few hundred parameters, each at relatively few samples per second makes Ethernet and standard upper layer protocols ideal for this application. The state-of-the-art human interface lets users select or mix a variety of methods to create and modify display contents, including: choosing from a list using arrow keys or a mouse, moving a scroll bar to pan through parameter files, or entering commands via keyboard where response anticipation reduces keystrokes to those uniquely defining a choice. A repertoire of graphic window displays is available to present real-time and static data concisely in analog and alphanumeric formats. Window size, location, and color have been chosen to focus attention rather than beautify. Standard windows and accent colors direct user attention to specific areas without cluttering and distracting.
    • A DPCM Approach to Video Compression

      West, Jim; Moore, Willard; LORAL/CONIC (International Foundation for Telemetering, 1988-10)
      This paper presents a working Variable Length Differential Pulse Code Modulation (VDLPCM) video compression/decompression and encryption system. Included are theory of operation and performance characteristics, as well as a study of packaging problems which arise from using this hardware for severe environmental applications. No classified issues are covered.
    • Draft Standard for Digital Transmission of Television Images

      Rieger, James L.; Gattis, Sherri; Naval Weapons Center (International Foundation for Telemetering, 1988-10)
      This paper describes the characteristics of the HORACE digital protocol intended for transmission of black-and-white standard television images and associated data through a digital channel and reconstruction of an NTSC standard television picture at the receiving end, using adaptive transmission to allow maximum picture quality at a selected data rate. Tradeoffs are discussed for transmission rates in the range from near DC to over 40 Mbits/second. The HORACE protocol will be a government test range standard to be issued by the Telecommunications Group [TCG] of the Range Commanders' Council as RCC Document 209.
    • Evolutionary Factors in the Development of a Realtime Multiprocessor System

      Trover, William F.; Teledyne Controls (International Foundation for Telemetering, 1988-10)
      Architectural decisions made three years ago in the design of a high speed preprocessor system for realtime data processing at sustained rates of 200k to 300k parameters per second were driven by the need to provide expansion flexibility and to permit the user to program application algorithms through the use of a high level language. The original design concept was a two bus architecture which would accept and merge data from up to 8 data sources with the required number of parallel computers driven by the realtime processing needs - not the 1.5M wps aggregate throughput capability. Other configuration variables were to enable the use of an optional raw data circular (wrap around) file for intermaneuver or anomaly analysis, the number of analog and discrete outputs for strip chart and visual displays, and the ability to support a wide range of processed data throughputs to one or more host computers. As a result of future defined requirements, the expansion capability ultimately grew to allow up to 30 data sources, 256 analog outputs, and 196 discrete outputs. A concurrent study of the engine and airborne test community showed that in many applications over 50% of the processing was restricted to repetitive computations such as FFTs and first order EU conversions. Although bit slice processors were much faster than general purpose Application Processors (APs), nobody in the user community said they wanted to write microcode to install their application programs. As the first customer's requirements could be easily handled by adding a few APs, the initial system design concentrated only on general purpose processors with provisions being made for the future addition of special purpose digital signal processors to co-reside with the general purpose APs. At the some time, much of the rotary wing test community's data processing was highly floating point intensive so the AP processor was designed with an independent floating point processor using the fastest possible device technology. The original two bus architecture using industry standard Versa and VME buses evolved as the design matured to a six bus architecture capable of supporting up to 60 parallel processors. The use of industry standard buses has permitted successful development of configurations using a wide range of third party processors and peripherals from a variety of sources. Larger system configurations are implemented by a multi-chassis structure with functions arranged so that no realtime bus is unterminated or physically longer than 19 inches. The simultaneous software development supporting these changes and encompassing 25 man-years of work is beyond the scope of this paper and will be covered in a separate publication.
    • Fiber-Optic Local Area Network for Real-Time Telemetry

      Bartley, Tom; Loral Instrumentation (International Foundation for Telemetering, 1988-10)
      For years, standard telemetry decommutators have proven the practical effectiveness and other advantages of using a data-driven (or data flow) broadcast bus for collecting, merging, and distributing continuous flow, real-time data. Bus length constraints have limited the use of the wideband broadcast bus to within a single chassis or closely mounted multiple chassis. Standard fiber-optic interfaces now make it possible to extend a real-time, greater than 5 million word/sec tag and data broadcast bus over kilometers at costs comparable to computer local area networks (LANs). Other advantages of this type of LAN include: no software protocol or handshaking, great flexibility in widely distributed processing and data base management, data security, and readily available off-the-shelf products. This paper discusses design considerations for conceptual networks, shows a sample design based on standard products, and suggests opportunities for product development for various types of network nodes. Also discussed are the implications to distributed processing and merging of real-time continuous data streams into the more blocked environment of general purpose computer processing and data base management.
    • A Flexible Telemetry Processor for Spacecraft Testing

      Leng, Christopher; Peet, Arthur; Jet Propulsion Laboratory/California Institute of Technology; Martin Marietta Astronautics Group (International Foundation for Telemetering, 1988-10)
      In the past, telemetry data systems in support of JPL flight projects -- such as Voyager and Galileo -- were designed specifically for each mission. Third-generation computers and minicomputers were combined into a distributed system, and many man-hours of software development were invested to meet each project's unique processing requirements. These systems were used to support the Spacecraft testing on the ground and -- later -- for mission operations after launch. The Magellan System Test Data Processing Subsystem (STDPS) marks a departure from these past designs. For the first time, a re-usable telemetry-processing subsystem has been designed that is flexible enough to meet the spacecraft-testing requirements of the present project -- and can be easily changed for future projects as well. These changes are all accomplished through a user-friendly, menu-oriented interface. Extensive software re-programming is no longer required. The Magellan spacecraft is being constructed for JPL by Martin Marietta Astronautics Group, Denver, Colorado. The STDPS is currently in Denver, supporting the spacecraft testing.
    • Flight Test of SDM Telemetry System

      Ming, Zheng; Qi-shan, Zhang; Beijing Institute Aeronautics and Astronautics (International Foundation for Telemetering, 1988-10)
      Orthogonal functions are the mathematical foundations of implementing multiplex transmission. Walsh functions are a set of functions which are orthogonal, normalized, and complete. They can also be used to accomplish multiplex transmission - constituting a new kind of telemetry system. In this paper, the constitutive principle of Walsh function telemetry system is introduced, the Walsh function telemetry system has already been built, the experiments performed recently on this system and the results of flight experiment are comprehensively discussed.
    • A Four-State Trellis-Coded 8-PSK Modulation Computer Simulation

      Kopp, Brian; New Mexico State University (International Foundation for Telemetering, 1988-10)
      The continuing growth of the telecommunications industry has created a steadily increasing need for higher performance communications systems - systems that can transfer data at faster rates while meeting stringent bit error rate requirements. In the case of satellite and mobile communications these same systems must also maintain minimum size and power consumption requirements. To help implement this industry demand computer simulations of communications systems can be a viable tool. Simulators can be used to demonstrate feasibility while maintaining minimum research and development costs during the design phase of these new and more complex communications systems. One type of system where simulation has proved helpful has been trellis-codedmodulation (TCM). This paper documents a simulation of a four-state trellis-coded eight- PSK modulation scheme currently being researched at New Mexico State University (NMSU). In the past simulations of convolutionally coded schemes have used binary symbols in the decoding process. In TCM the Euclidean space components of the modulation scheme are used in place of the binary symbols. The simulator under development incorporates these Euclidean signal components which are taken from an eight-PSK signal constellation. Soft-decision maximum likelihood decoding using trellis trace-back techniques are then applied to the Euclidean signal components to recover the simulated transmitted data. The simulator supplies the user with the number of undetected errors generated during a simulation as well as the bit error rate for a given signal to noise ratio. This simulator is intended to provide an environment for investigating improved communication system designs and it is hoped that the results that are obtained from such telecommunication simulators will help satisfy the ever increasing demands of the telecommunications industry. It should be noted that the research being conducted at NMSU on TCM is being directed by Dr. Frank Carden. The development of the simulator was conducted by the author to assist Dr. Carden in the continuing investigation of TCM.
    • Functional Component Approach to Telemetry Data Capture Systems

      Sabia, Steve; Hand, Sarah; NASA, Goddard Space Flight Center (International Foundation for Telemetering, 1988-10)
      To support the telemetry data rates and meet the needs of telemetry data users in the next decade, telemetry data capture systems will have to be radically different from today's systems. At Goddard Space Flight Center, the Mission Operations and Data Systems Directorate is developing the capability to build user specific data capture systems from a library of high performance hardware and software elements that satisfy standard data capture processing requirements. One or more telemetry functions are encapsulated in a single standard open bus system (e.g. VME, Multibus II, NuBus etc.) with supporting software to form a user data capture system. Each subsystem module (card or board) includes a local microprocessor supplying on board intelligence and programmability for changing requirements. Many of these subsystem designs include custom very large scale integration (VLSI) components to increase speed while minimizing cost and size. A standard hardware and software interface to each card subsystem is employed to simplify system integration in the open system environment.
    • Generic Decommutation Capabilities in the Space Flight Operations Center

      O'Brien, Robin A.; Jet Propulsion Laboratory/California Institute of Technology (International Foundation for Telemetering, 1988-10)
      A generic decommutation capability has been created as part of the Space Flight Operation Center's goal of developing a multi-mission telemetry system. Generic decommutation involves separating the algorithmic description for extracting data from the actual implementation of decommutation. This was done by creating a Decommutation Map Language, which allows mission designers to describe decommutation algorithms without the restrictions imposed by a standard programming language. A Decommutation Map Compiler converts this description into C code, which is then linked with a decommutation library to provide an executable decommutation program. So far, this approach has been used successfully to decommutate several different types of data.