• Edwards Digital Switch System Overview

      Switzer, Earl R.; Straehley, Erwin H.; Edwards Air Force Base; Straehley Associates (International Foundation for Telemetering, 1992-10)
      The Edwards Digital Switch (EDS) is a digital communication system that provides advanced voice networking capabilities to the Edwards Test Range. The EDS is a member of a new family of all-digital switching systems that internally handle data in digital form. To accommodate analog voice and data circuits, conversions between analog and digital formats occur at the system interfaces. The EDS consists of six groups of configuration items: System-level control and monitoring is centralized in the Control and Display Subsystem. Workstations provide subsystem-level control and monitoring. The Central Switching Subsystem, as the primary interface with the range environment, provides system connectivity to radios, telephone circuits, and communications links to other facilities. It integrates the EDS with links to the Control Room Switching Subsystems. Each Control Room Switching Subsystem connects individual user stations within a Mission Control Room or other localized area. The user equipment element consists of a Subscriber Terminal Unit, Channel Expander, and interface panels for headsets, foot switches, and speakers. The Remote Radio Control Unit optimizes usage of available frequencies, allowing control of tunable radios from the Control and Display Subsystem. *The original name, Edwards Communication Switching System (ECSS) was changed to Edwards Digital Switch (EDS) in 1990. The Site Selection Unit facilitates the handover of voice communications between receiver sites when a long-range test is monitored. The system architecture is based on a central system-level control element, a central switch, multiple subsystem-level control elements, multiple subsystem switches, and end-equipment items that are interconnected through the switch network. The EDS combines multiple voice communications applications in a single system. The system is being expanded to integrate voice and data switching. Its major function is support of multiparty networked voice communications within Mission Control Rooms and between other test participants. Other voice functions are an intercom capability including both Direct Access (hot line) and Indirect Access (dial-up), subscriber loop connections to the base-level telephone exchange, and the Public Switched Network System. Digital interfaces allow integration of ciphertext data and Time Space Position Information data switching functions. A system based on the EDS design has also been installed by the Air Force at Eglin AFB. Engineering studies for systems that make use of the EDS design are currently underway by the Navy at China Lake and the Army at White Sands Missile Range. The EDS project office has actively pursued promising program management concepts such as: specifying nondevelopmental items, requiring industry standard interconnectivity and interoperability, and using a multiyear fixed-price requirements-type contract to encourage multiservice participation.
    • Data Rate Upgrade of the DFCS Waveform

      Walthall, David; Eglin Air Force Base (International Foundation for Telemetering, 1992-10)
      New tracking/control system requirements demand that the present DFCS/GRDCUS/MTACS data link bit rate be increased. A possible method for achieving this increase is to select two additional 31-bit chip code patterns that are orthogonal to the present chip codes, and to each other. This method will not require any more bandwidth than the present 10 MHZ used. This method suggest that each of the four chip code patterns are assigned a two bit value ie: 00, 01, 10, 11. At present, the two correlated chip codes represent data in a pulse position method. No data is contained in which of the two chip codes actually correlated. This new method suggest each of the four chip code patterns will still perform the pulse position modulation and provide two additional bits of data. These additional two bits of data will up the data rate of the link by 100 percent.

      Jacobsen, H. D. (International Foundation for Telemetering, 1992-10)
      Lempel-Ziv-Welch (LZW) algorithm is a popular data compaction technique that has been adopted by CCITT in its V.42bis recommendation and is often implemented in association with the V.32 standard for 9600 bps modems. It has also been implemented as Microcom Networking Protocol (MNP) Level 7, where it goes by the name of Enhanced Data Compression. LZW compacts data by encoding frequently occurring input strings with a single output symbol. The algorithm automatically generates a string dictionary for each symbol at each end of the transmission path. The amount of compaction that can be derived with the LZW algorithm varies with the type of data being transmitted and the efficiency by which table entries can be indexed. Table indexing is usually implemented by use of a hashing table. Although some manufacturers advertise a 4-to-1 gain in throughput, this seems to be an extreme case. This paper documents a implementation of the exact ZLW algorithm. The results presented in this paper are significantly less, typically on the order of 1-to-2 for ASCII text, with substantially less compaction for pre-compacted files or files containing random bit patterns. The efficiency of the LZW algorith on ASCII text is shown to be a function of dictionary size and block size. Although fewer transmitted symbols are required for larger dictionary tables, the additional bits required for the symbol index is marginally greater than the efficiency that is gained. The net effect is that dictionary sizes beyond 2K in size are increasingly less efficient for input data block sizes of 10K or more. The author concludes that the algorithm could be implemented as a direct table look-up rather than through a hashing algorithm. This would allow the LZW to be implemented with very simple firmware and with a maximum of hardware efficiency.
    • How The User Relates to a Large Range Telemetry System

      Chavez, Tomas; Strock, O. Jud; White Sands Missile Range; Loral Data Systems (International Foundation for Telemetering, 1992-10)
      The Telemetry Data Handling System (TDHS) at the Telemetry Data Center in White Sands Missile Range (WSMR), New Mexico, has been in operation since January 1990. It is one of the world's largest integrated range telemetry systems, and certainly the most versatile in weapons support capability. The system supports one of the world's busiest test ranges, serving all U.S. Military Services as well as NASA and others. This paper looks at the White Sands system from the user's view, examining the ways in which it is configured for several weapons tests in a typical day, and the way in which it can run foreground launch support and background pre-launch activities simultaneously. This system has grown in functional capability since its installation, both in hardware and in software. This paper analyzes that growth to see the reasons and methods. Also, near-term additional growth is addressed.
    • The Architecture and Design of Parallel Processing for Real-Time Multiplexing Telemetry Data

      Jun, Zhang; Qishan, Zhang; Beijing University of Aeronautics and Astronautics (International Foundation for Telemetering, 1992-10)
      The parallel processing technology has been widely applied to many science and engineering technical fields, also to telemetry. In particular, telemetry develops towards the trend of large capacity, high rate, several data streams and programmable formats. This sets a still higher demand on processing for real-time multilexing telemetry data. On the basis of analyzing of the characteristics of telemetry data processing (TDP), the parallel processing conception and methods are adopted, countering multiiple-channel data streams of different objects, several architectures of parallel processing for real-time multiplexing telemetry data are presented. It makes better use of the concurrency during the process of TDP and handles the telemetry information effectively in every processing level of the whole telemetering information processing system. The paper shows the property comparison of these parallel processing architectures and main features too. Experiments have indicated that it is an economical and effective method to improve the performance of telemetry information processing system by using paralle processing architecture which is based on concurrency of telemetry data processing.
    • TECNET Research and Development Initiatives

      Hurlburt, George F.; Naval Air Warfare Center, Aircraft Division (International Foundation for Telemetering, 1992-10)
      BACKGROUND - THE TECNET VISION STATEMENT: The Test and Evaluation Community Network (TECNET) is governed by a Tri-service Steering Committee which reports to the Joint Commander's Group for Test and Evaluation (JCG(T&E)). In keeping with its JCG(T&E) approved TECNET Project Management Plan (PMP), the TECNET Steering Committee adopted the following TECNET Vision Statement in 1991: "To systematically migrate existing TECNET resources to a standards compliant, multi-level secure communications and processing capability which links DoD test and evaluation entities to a shared, but controlled user community information resource". TECNET GENERAL RESEARCH AND DEVELOPMENT: The life blood of ongoing TECNET operations is the continual improvements and user support provided by a leading University. This Research and Development contract directly contributes to the continued well being of TECNET. This contract sustains TECNET as a state of the art communication tool for its users who are continually increasing their capabilities. They expect their T&E network to keep pace. This is particularly true as more executive users adopt TECNET. PLANNED MULTI-LEVEL SECURE (MLS) EXPERIMENTS: Near term MLS experiments are designed to lay a foundation for longer term objectives. The foremost characteristic of the second generation TECNET is that host computers and all associated user nodes be eventually capable of processing information ranging in classification from UNCLASSIFIED through SECRET, depending upon the nature of the information requirements of the user. Specific components of the TECNET MLS plan include secure network devices and MLS accredited hardware running MLS accredited software. These characteristics will permit TECNET to operate in the requisite secure mode per COMSEC directives, support T&E program officials and T&E practitioners with timely and meaningful value added information concerning T&E, and permit near real time exchange of T&E data. MLS experiments are tri-service in nature. DATA DISTRIBUTION RESEARCH: The TECNET Distributed Data Plan calls for tri-service participation in building a T&E common data dictionary in 1992. The RCC agreement to form a common Range data Dictionary Group sets the stage for such a cooperative effort. One necessary and highly desired product of this process is a detailed catalog of all known and emerging T&E related data bases. TECNET plans to field and populate such a catalog of T&E data bases during 1992. Further, using the generic data extraction and conversion tool offered to TECNET, the demonstration of third party data base data population from the ranges will be accomplished. A significant effort has been undertaken to perform the necessary analysis to establish this tool to work with the RCC defined common data elements and the target data bases. Finally, TECNET proposes to develop specific training materials in print and computer based training media, as well as on site training support, for selected data bases of widespread value to the T&E community.

      Gelhaar, B.; Alvermann, K.; Dzaak, F.; Institute For Flight Mechanics (International Foundation for Telemetering, 1992-10)
      For research purposes on helicopter rotor acoustics a large data acquisition system called TEDAS (Transputer based Expandable Data Acquisition System) has been developed. The key features of this system are: unlimited expandability and sum data rate, local storage of data during operation, very simple analog anti aliasing filtering due to extensive digital filtering, and integrated computational power which scales with the number of channels. The sample rate is up to 50 kHz/channel, the resolution is 16 bit, 360 channels are realized now. TEDAS consists of blocks with 8 A/D converters which are controlled by one transputer T800. The size of the local memory is 4 Mbyte. Any number of blocks (IDAM = Intelligent Data Acquisition Module) can be combined to a complete system. Data preprocessing is done in parallel inside the IDAMs. As for 16 bit systems the analog antialiasing filtering becomes a dominant factor of the costs, delta sigma ADCs with oversampling and internal digital filtering are used. This produces an exact linear phase and a stop band rejection of -90 dB.
    • NAVSTAR Global Positioning System Applications for Worldwide Ionospheric Monitoring

      Moses, Jack; SPARTA, Inc. (International Foundation for Telemetering, 1992-10)
      The ionosphere is a critical link in the earth's environment for space-based navigation, communications and surveillance systems. Signals sent down by the GPS satellites can provide an excellent means of studying the complex physical and chemical processes that take place there. GPS uses two frequencies to ascertain signal delays passing through the ionosphere. These are measured as errors and used to correct position solutions. Since this process is a means of measuring columns of Total Electron Content (TEC), multiple top-soundings from the GPS constellation could provide significant detail of the ionospheric pattern and possibly lead to enhancement of predictions for selectable areas and sites. This paper addresses transforming the GPS propagation delays (errors) into TEC and providing TEC contours on a PC-style workstation in real and integrated time and discusses a worldwide ionospheric network monitoring system.
    • Multiplexer-Demultiplexer for High Speed Digital Recorders

      Pouille, Etienne; Schlumberger Industries (International Foundation for Telemetering, 1992-10)
      This paper describes a multiplexer-demultiplexer for high speed digital recorders. The multiplexer-demultiplexer enables a single-channel recorder (for example, MIL-STD-2179 recorders) to be used with up to eight asynchronous data channels, each channel being analog or digital. Time correlation between the different channels is preserved. The multiplexer and the demultiplexer are modular products and can be used under different environments (ships, aircraft, laboratory, ...).
    • GPS-Trak Low Cost Alternative to Auto-Tracking Using GPS and Multimode Single Axis Antenna Techniques

      Sullivan, Arthur; Arthur Sullivan & Associates (International Foundation for Telemetering, 1992-10)
      The GPS Satellite System provides precise determination of time, space, and position of aerospace (airborne) vehicles during flight and flight test situations. The cost of "GPS" equipment has been decreasing dramatically -- a phenomenon similar to that which was experienced with "hand held" calculators 20 years or so ago. By the use of a multigain (and beam) antenna and GPS, a very low cost single axis system can be utilized for reception of telemetry and at the same time to provide accurate position, velocity, and acceleration information concerning the airborne vehicle.
    • Distributed Systems Integration and Implementation Techniques in a Network Based Telemetry System

      Kelley, Jeffrey D.; Loral Data Systems (International Foundation for Telemetering, 1992-10)
      This paper addresses the distributed systems implementation techniques used in the development of the EMR O/S90 Open Systems Telemetry System. Specifically, it presents the integration, networked load-balancing, and remote control aspects of the telemetry system which allow it to adapt to differing configurations and availability of resources.

      Johnson, Carl E.; NASA (International Foundation for Telemetering, 1992-10)
      The ethernet technology has vastly improved the capability to make real-time decisions during the flight of a vehicle. This asset combined with a PC telemetry data processor and the power of a high resolution graphics workstation, allows the decision makers to have a highly reliable graphical display of information on which to make vehicle related safety decisions in real-time.
    • Smart Modularized Advanced Reusable Telemeter (SMART)

      Daniels, R. M.; Sheaffer, D. A.; Sandia National Laboratories (International Foundation for Telemetering, 1992-10)
      The SMART (Smart Modularized Advanced Reusable Telemeter) is an advanced telemetry system. The SMART system enhances the quality of a weapon system by providing an adaptable built-in telemetry capability for the weapon. Existing weapon telemetry systems are centralized, separate components which require many fault-prone interconnections. This system reduces the number of interconnections and provides higher performance than current systems. The modular system uses a high data-rate serial data link that connects remote measurement modules located throughout the unit-under-test. A smart processor is used to analyze and compress data from the various modules prior to transmission, making more effective use of the telemetry bandwidth. The smart processing unit also adapts the measurement units for changing test conditions on-the-fly. The system will allow more complete testing of the weapon system and solve a broader range of problems. The goal of the SMART project is to utilize the most advanced technology to overcome the current design methodologies that have perpetuated shortcomings in present systems. This project is being conceptualized to encompass a broader range of telemetry applications beyond the present weapon systems at Sandia.
    • F/A-18 Data Reduction at the Naval Air Warfare Center, China Lake, California

      Smith, Darren C.; Naval Air Warfare Center - Weapons Division (International Foundation for Telemetering, 1992-10)
      The current F/A-18 data reduction/analysis system is incapable of meeting increased customer demands. A new system has been developed and is based on new technologies. In the process of developing the new system, the design team had to divorce themselves from the current system and consider what the ideal system would consist of. This was accomplished with great success in the areas of timeliness of data turn around, customer satisfaction, and increased efficiency.
    • A Single Channel Monopulse Antenna with Low Effective Sidelobes

      Dunn, Daniel S.; Augustin, Eugene P.; Technical Systems Associates, Inc. (International Foundation for Telemetering, 1992-10)
      This paper describes a CSC² single axis tracking antenna using a single channel monopulse antenna which has improved sidelobe performance over conventional single channel monopulse antennas. Effective sidelobes of the composite pattern, measured at the receiver input, greater than 22 dB have been achieved. This is due to a unique feed design. The composite patterns are the true measure of performance for a single channel monopulse system since this is the input to the tracking receiver. The low effective sidelobes result in a significant reduction of multi-path problems.
    • ESA Tracking Systems

      Girardey, Catherine C.; California Institute of Technology (International Foundation for Telemetering, 1992-10)
      This paper presents the tracking systems currently used at ESA. Two systems are described: Meteosat Ranging System (MRS), and Multi-Purpose Tracking System (MPTS). The MRS is presently in operational use on Meteosat. It has been designed to meet the need for a simultaneous multi-point ranging in a channel shared with other services. As a result, a new code ranging technique, based on split-phase-level data formats, has been designed and developed. The MPTS (previously Deep Space Tracking System - DSTS) was first developed and deployed for the Giotto mission. At a later stage, a near-earth capability has been added to the system, thereby creating a truly multi-purpose tracking system. The ranging signal employed in the MPTS makes use of the good properties of both the PN code type of ranging system and the tone ranging system. The concept, architectural design, capabilities and performance of these systems are presented in this paper. Finally, insight into the European Data Relay Satellite and Data Relay User Satellite ranging systems is given.
    • Multichannel Digital Signal Processor Based Red/Black Keyset

      Smith, Quentin D.; Communications Systems Technology, Incorporated (CSTI) (International Foundation for Telemetering, 1992-10)
      This paper addresses a method to provide both secure and non-secure voice communications to a DS-1 network from a common keyset. In order to comply with both the electrical isolation requirements and the operational security issues regarding voice communications, an all-digital approach to the keyset was developed based upon the AD2101 DSP. Protocols that are handled by the keyset include: Multiple PTT modes, hot mike, telephone access, priority override, direct access, indirect access, paging, and monitor only. Special features that are addressed include: independent channel by channel assignment of access protocols, headset assignment, speaker assignment, and PTT assignment. Multiple microprocessors are used to implement the foregoing as well as down-loadable configurations, remote keyset control and monitoring, and composite audio outputs. Partitioning of the digital design provides RED to BLACK channel isolation and RED channel to AC power isolation of greater than 107 dB.

      Eccles, Lee H.; Boeing Commercial Airplane Group (International Foundation for Telemetering, 1992-10)
      A family of data recorders are being developed for use by the Boeing Commercial Airplane Company in flight testing the 777 airplane. The intention is to have a family of recorders which all have the same interface to the recording and monitor systems but have vastly different data rates and capacities. At this time two recorder systems are being developed. The large recorder will be an Ampex DCRSi with a custom interface for the new data acquisition system. The small recorder will be an Exabyte Model 8500 with a similar interface to the one being used in the DCRSi. An intermediate recorder may be developed if the economics of the system show that it would be cost effective but, it is not presently under development. This paper discusses the recorders, the modifications necessary to develop the interfaces and the interfaces themselves for both the large and small recorders.
    • A Software Architecture for Realtime Data Acquisition, Instrument Control and Command Processing

      Tolat, Viral V.; Stanford University (International Foundation for Telemetering, 1992-10)
      In this paper we describe the flight software for the SETS (Shuttle Electrodynamic Tethered System) experiment. The SETS experiment will fly as part of the TSS-1 (Tethered Satellite System) experiment on STS-46 currently scheduled for July 1992. The software consists of two major components: the SETSOS (SETS Operating System) and the SETS Application. The SETSOS is a UNIX-like operating system developed especially for realtime data acquisition, instrument control and command processing. The SETSOS, like all operating systems, provides resource management for application programs. It is UNIX-like in that access to resources is provided through a standard set of UNIX system calls. The SETSOS also implements the standard UNIX I/O model and a hierarchical file system. In addition to providing access to physical devices, the SETSOS provides support for two virtual devices: a packet-based data device and a command device. The packet-based data device is used by applications to place data into the telemetry stream. The command device is used to manage commands from the command uplink as well as other sources including other applications and other processors. The SETS Application is the primary program which runs under the SETSOS to handle data acquisition, instrument control and command processing. It executes as 5 separate processes, each performing a special task. The tasks include housekeeping data acquisition, limit checking, timeline management, and command processing. The processes communicate via shared memory. Time critical processing is coordinated by using signals and interrupts. In addition to a description of the software, we will discuss the relative merits and tradeoffs of using such a system design for command processing and data acquisition.
    • The Shipboard Antenna Tracking System of Telemetry

      Quan-Hui, Gao; Beijing Research Institute of Telemetry (International Foundation for Telemetering, 1992-10)
      This paper describes a C-band auto-tracking receiving system on shipboard which is used in satellite telemetry. The system consists of receiving antenna, wideband feed, antenna pedestal, telemetry/tracking receiver antenna controller and computer console. Its characteristics are as follow: Single Channel Single Pulse Tracking Feed, 2. 5m Antenna Diameter, 500MHz BW, LHCP and RHCP Dual - Channel Polarization Diversity Receiving. The servo system uses rate - gyros as stabilized element being based on the micro - processor to realize the digital servo control. Computer console performs the status monitoring and management to the whole system. The system design, the main system specification and important test results are given.