Schwartz, Paul D.; Hersman, Christopher B.; The Johns Hopkins University (International Foundation for Telemetering, 1994-10)
      A system to generate a contiguous high speed time division multiplexed (TDM) spacecraft downlink data stream has been developed. The 25 MBPS downlink data stream contains high rate real time imager data, intermediate rate subsystem processor data, and low rate spacecraft housekeeping data. Imager data is transferred directly into the appropriate TDM downlink data window using control signals and clocks generated in the central data formatter and distributed to the data sources. Cable and electronics delays inherent in this process can amount to several clock periods, while the uncertainty and variations in those delays (e.g. temperature effects) can exceed the clock period. Unique (patent pending) electronic circuitry has been included in the data formatter to sense the total data gathering delay for each high speed data source and use the results to control series programmable delay elements to equalize the delays from all sources and permit the formation of a contiguous output data stream.

      Crouch, Viv; Goldstein, Anna; RAAF Base; Loral Test & Information Systems (International Foundation for Telemetering, 1994-10)
      The Aircraft Research and Development Unit (ARDU) of the Royal Australian Air Force (RAAF) is the only agency in Australia that performs the full spectrum of military flight testing and is the new custodian of the instrumented weapons range at Woomera. Receiving early attention will be the upgrade and integration of ARDU's telemetry systems with the meteorological and tracking data acquisition capabilities at Woomera to minimize overhead and data turnaround time. To achieve these goals, maximum modularity, extensibility, and product interoperability is being sought in the proposed architecture of all the systems that will need to cooperate on the forecast test programmes. These goals are also driven by the need to be responsive to a wide variety of tasks which presently include structural flight testing of fighter and training aircraft, weapons systems performance evaluation on a variety of combatant aircraft, and a host of other tasks associated with all fixed and rotary wing aircraft in the Army and Air Force inventory. Of all these tasks however, ARDU sees that responsiveness to future testing of F-111Cs fitted with unique Digital Flight Control Systems along with USAF standard F-111Gs may place the most significant demands on data handling —particularly in regard to providing an avionics bus diagnostic capability when performing Operational Flight Programme (OFP) changes to the mission computers. With the timely assistance and advice of Loral Test & Information Systems, who has long-term experience in supporting USAF F-111 test programmes, ARDU is confident of making wise design decisions that will provide the desired flexibility and, at the same time, minimize life-cycle costs by ensuring compliance with the appropriate telemetry and open systems standards. As well, via cooperative agreements with the USAF, the potential exists to acquire proven software products without needing to fund the development costs already absorbed by the USAF. This paper presents ARDU's perception of future needs, a view by LTIS of how best to meet those needs, and, based on ARDU data, a view of how LTIS' proposal will satisfy the requirement to provide maximum extensibility with minimum life-cycle costs.
    • Improved Groundstation Consoles Using New Visualization Techniques and Graphics Technology

      McDaid, John P., Jr.; Loral Test & Information Systems (International Foundation for Telemetering, 1994-10)
      The advance from alphanumeric terminals to displays using new graphics technologies like the X Window System and Microsoft Windows has in many cases failed to tap the full potential of these technologies. Many common telemetry tasks continue to use similar user interfaces based on tabular real-time data displays and menus. This paper will demonstrate the application of new techniques which, when used with emerging graphics technologies, will maximize the effectiveness of telemetry ground station consoles. Advances in visualization and animation have greatly enhanced the information content of current displays and significantly improved their ease of use.

      Richard, Gaetan C.; Gonzalez, Daniel G.; DECS, Inc; Malibu Research, Inc (International Foundation for Telemetering, 1994-10)
      The design of a telemetry tracking system is generally centered around its desired RF performance which is typically specified in terms of beamwidth, gain and/or G/T. These parameters determine the size of the reflector used in a given application and consequently dictate the required size and performance of the associated pedestal. Any subsequent improvement in the RF performance of such a system is primarily achieved by increasing the size of its reflector. The magnitude of the improvement realized is therefore limited by the load handling capability of the pedestal. In most instances, the substitution of a larger reflector with its increased inertia and wind loading causes a significant degradation in the dynamic performance of the tracking system. This paper describes how the figure of merit (G/T) of a specific dual axis telemetry tracking system can be improved by a minimum of 7.3 dB/K° without impacting its dynamic performance or increasing its weight. These impressive results are made feasible by the innovative pairing of a unique design planar reflector with a novel implementation of the conical scanner technology. The FLAPS™ reflector incorporates a newly developed concept which features lightweight construction and very low wind load coefficients [1, 2]. The conical scanner is a lightweight version of the DECS tracking feed system described in the referenced technical paper [3].
    • INTA Mobile Telemetry Acquisition System

      Armengod, Rafael G.; Coll, Vicente Millet; Leon, Rosendo J.; Instituto Nacional de Technica Aeroespacial; Microdyne Corporation (International Foundation for Telemetering, 1994-10)
      INTA is the Institute for Aerospace Technologies in Spain. Test programs at INTA require extensive flight test capabilities and for this reason in mid 1990, INTA created the Flight Test Center, designated CEA. The CEA is responsible for providing flight test support for all current and future programs including RPV Test, Rocket Launches, Balloons and Missile Test. With the increasing requirement for flight test at several locations throughout Spain, a program was launched to acquire a mobile capability which could support these test ranges in current flight test requirements as well as anticipated future requirements.
    • International Telemetering Conference Proceedings, Volume 30 (1994)

      International Foundation for Telemetering, 1994-10
    • Low Cost Vector Scoring System for Airborne Targets

      Whiteman, Don; Bradley, Joe; Naval Air Warfare Center, Weapons Division (International Foundation for Telemetering, 1994-10)
      Testing of airborne weapons systems often requires that a scoring system be placed on the target drone to obtain critical miss distance data. Advanced weapons utilizing directional warheads often require a scoring system which yields vector, miss distance and miss direction, information. Scalar scoring systems currently in use are relatively simple and inexpensive. Vector scoring systems are typically complex and the cost of systems which are currently available or are being developed can be prohibitively expensive. Due to the current military budget decline, development of a low cost vector scoring system is desirable This paper introduces a low cost vector scoring system developed for airborne target drones and based on an inexpensive scalar scoring system currently in use. To meet the low cost criteria, vector operation is achieved via minimal modifications to the existing scalar system.

      Lundberg, L. L.; Naval Air Warfare Center (International Foundation for Telemetering, 1994-10)

      Wu, Wei-Ren; Li, Hua; Beijing Research Institute of Telemetry (International Foundation for Telemetering, 1994-10)
      A real time distributed computer telemetry system based on network is described. It is a new generation of open telemetry system in China, which can parallel acquire and process up to 8 data streams of 100bps~3.5Mbps and optimize automatically distribution of processing tasks by using load-balance technique. PCM PSK QPSK PACM may be suitable to the system and the format switched within less than 1 second. The system has been successfully used in the field of aerospace. There are models of automobile, shipboard, airborne as well as ground station for the system. This paper discusses mainly system architecture, performance, principle, and system features.
    • Network Configuration for Range Interconnectivity

      Douglas, Steven R.; Naval Warfare Assessment Division (International Foundation for Telemetering, 1994-10)
      A demonstration of near real-time performance assessment for the Program Executive Officer for Cruise Missiles Project and Unmanned Aerial Vehicles, Cruise Test Directorate, PEO(CU)-CT, was conducted between 22 March 1994 through 4 May 1994. The demonstration involved the temporary installation of a portable TOMAHAWK telemetry recording and telecommunications capability at the Air Force Development Test Center range at Eglin Air Force Base, Florida and a receiving telecommunications capability at the Naval Warfare Assessment Division (NWAD), Corona, California. The system was successfully used on 4 May 1994 to record TOMAHAWK missile telemetry data in real-time in support of Operational Test Launch (OTL)-163 and to transfer that data to the weapons system performance analysts at NWAD in near real-time. The one hour and three minutes of flight data was compressed in real-time as it was recorded, then, after completion of the flight, the data was transferred to NWAD in about 12 minutes using the switched 56 kbps network. Additional transfers using the Defense Commercial Telecommunications Network (DCTN) were also conducted. All transfers were secured using ethernet encryptors. The data was processed by both the NWAD telemetry ground station and the TOMAHAWK workstation complex. This paper quantifies the results and documents the lessons learned from this demonstration and proposes a standardized system design for possible implementation at TOMAHAWK test range sites in the future. A position is taken that for situations where the remote site (e.g. other range or data analysis site) does not exercise direct operational control over the test/host range, near real-time data relay solutions are not only as adequate, but in many cases are preferable to real-time solutions.
    • A New Error Control Scheme for Remote Control System

      Zhou, Tingxian; Yin, Xiaohua; Zhao, Xianming; Harbin Institute of Technology (International Foundation for Telemetering, 1994-10)
      How to rise the reliability of the data transmission is one of the main problem faced by modern digital communication designers. This paper studies the error-correcting codes being suitable for the channel existing both the random and burst error. A new error control scheme is given. The scheme is a concatenated coding system using an interleaved Reed-Solomon code with symbols over GF (24) as the outer code and a Viterbi-decoded convolutional code as the inner code. As a result of the computer simulation, it is proved that the concatenated coding system has a output at a very low bit error rate (BER)and can correct a lot of compound error patterns. It is suitable for the serious disturb channel existing both the random and burst error. This scheme will be adopted for a remote control system.
    • On-Board Spacecraft Time-Keeping Mission System Design and Verification

      Wickham, Mark E.; Fairchild Space & Defense (International Foundation for Telemetering, 1994-10)
      Spacecraft on-board time keeping, to an accuracy better than 1 millisecond, is a requirement for many satellite missions. Scientific satellites must precisely "time tag" their data to allow it to be correlated with data produced by a network of ground and space based observatories. Multiple vehicle satellite missions, and satellite networks, sometimes require several spacecraft to execute tasks in time phased fashion with respect to absolute time. In all cases, mission systems designed to provide a high accuracy on-board clock must necessarily include mechanisms for the determination and correction of spacecraft clock error. In addition, an approach to on-orbit verification of these mechanisms may be required. Achieving this accuracy however need not introduce significant mission cost if the task of maintaining this accuracy is appropriately distributed across both the space and ground mission segments. This paper presents the mission systems approaches taken by two spacecraft programs to provide high accuracy on-board spacecraft clocks at minimum cost. The first, NASA Goddard Space Flight Center's (GSFC) Extreme Ultraviolet Explorer (EUVE) program demonstrated the ability to use the NASA Tracking and Data Relay Satellite System (TDRSS) mission environment to maintain an on-board spacecraft clock to within 100 microseconds of Naval Observatory Standard (NOS) Time. The second approach utilizes an on-board spacecraft Global Positioning System (GPS) receiver as a time reference for spacecraft clock tracking which is facilitated through the use of Fairchild's Telemetry and Command Processor (TCP) spacecraft Command & Data Handling Subsystem Unit. This approach was designed for a future Shuttle mission requiring the precise coordination of events among multiple space-vehicles.

      Morimoto, Todd A.; Nowitzky, Thomas E.; Grippando, Steven A.; Space & Missile Systems Center; Loral Space & Range Systems (International Foundation for Telemetering, 1994-10)
      An increasing number of satellite users and manufacturers are looking to lightweight, inexpensive satellites as substitutes to traditional large, expensive satellites with multiple payloads. Neither the Department of Defense nor the commercial sector can bear the financial or reputational consequences associated with massive program failures. With the low cost and weight of these new satellites, users can achieve mission success without great risk. One example of this new class of inexpensive spacecraft is the RADCAL (RADar CALibration) satellite. Detachment 2, Space & Missile Systems Center at Sunnyvale, CA operates the satellite. RADCAL is a 200-pound polar orbiting satellite with an average altitude of 450 miles. It is primarily used by 77 worldwide radars to calibrate their systems to within five meter accuracy. Also flying on board RADCAL is a communication payload for remote field users with small radios. The RADCAL program has satisfied all mission requirements. However, with the limited size and cost come certain challenges, both in the satellite and on the ground. Pre-launch testing was not as comprehensive as with more expensive programs; anomalies have arisen that require extensive workarounds. Data management is not a straightforward task, and it is sometimes difficult and inexact to track satellite performance. These challenges are presented with their solutions in the following discussion; this paper addresses the functional, operational, and testing aspects associated with the RADCAL satellite.
    • Optimum Symbol Synchronization

      James, Calvin L.; AlliedSignal Technical Services Corporation (International Foundation for Telemetering, 1994-10)
      Although most closed-loop synchronizers employ maximum likelihood estimators for symbol value decisions, in general, their symbol timing estimates are not optimum. It would seem only natural that an optimum timing estimator would choose interval partitions based on maximizing the observed sample signal-to-noise ratio. The symbol synchronizer described below achieves optimum performance when decisions on present symbol values are based on current and previously-received symbol samples. This procedure attempts to reestablish the interval independence criterion, thereby reducing timing estimator variance. The realization presented is motivated by an open-loop maximum a posteriori (MAP) structure analysis.

      Hui, Yang; Shanzhong, Li; Qishan, Zhang; Beijing University of Aeronautics and Astronautics (International Foundation for Telemetering, 1994-10)
      In this paper, a PCM telemetry system based on Personal computer is presented and some important methods that are used to realize the system will be introduced, such as a new kind of all digital PLL bit synchronizer and a way to solve the problem of high-rate data storage. The main idea of ours is to make the basic parts of PCM telemetry system (except receiver) in the form of PC cards compatible with EISA Bus, which forms a telemetry station with resource of PC computer. Finally, a laboratory prototype with rate up to 3.2Mbps is built.
    • Planned Evolution of Range Telemetry and Communications into the Public Data Network

      Erdahl, Mike; Loral Test & Information Systems (International Foundation for Telemetering, 1994-10)
      The area of range telemetry and communications has been under budget constraints and interoperability enhancement requirements for some time. The near-term onslaught of multimedia communications offerings by telephony and communications companies is certain to cause range engineering personnel to conduct extensive research and possibly make numerous decisions on procurements and technologies before standards are finalized. This paper will address a low-risk migration path for range telemetry to the new multimedia communications for ranges based on current capabilities. This migration path has an end goal of positioning the ranges to take advantage of future multimedia communications as they become available, while leveraging off of current products and procurements, without a major investment.
    • Portable Airborne Digital Data System Recorder

      Harris, Kevin E.; Veda Incorporated (International Foundation for Telemetering, 1994-10)
      Veda Incorporated has developed an airborne instrumentation recorder for a major commercial aircraft manufacturer. The recorder was developed for use in the aircraft company's Portable Airborne Digital Data System (PADDS), a small scale data acquisition and monitor system used for flight testing. The recorder is designed around an off-the-shelf 8mm tape drive, the Exabyte 8505. It records asynchronous, variable-rate data in a proprietary 24-bit recording format, and allows the data to be played back in real time. Its RS-422 control interface is designed to imitate the recorder used in the company's large scale data acquisition system, the Ampex DCRSi-II. Special provisions allow it to withstand the environment of an airplane's EE bay.

      Reinsmith, Lee V.; TYBRIN Corporation (International Foundation for Telemetering, 1994-10)
      This paper describes the application software used in the Message Processing System at the Air Force Development Test Center (AFDTC), Eglin AFB. The focus is on the Alpha AXP application software designed and developed to log, process, and reformat IRIG Chapter 8 1553 data. The main data reduction and editing capabilities of the processing phase are explained: message output selection, message output sampling, message translation, error identification, and IRIG Chapter 8 time editing. The design of and methods used to produce the output files, the BBNProbe STD file, and the 1553 message summary report are described. This software’s flexibility and comprehensiveness in processing, reducing, and re-formatting 1553 message data will enable AFDTC to satisfy current and future post-mission processing requirements.
    • Probability of Bit Error on a Standard IRIG Telemetry Channel Using the Aeronautical Fading Channel Model

      Nelson, N. Thomas; Brigham Young University (International Foundation for Telemetering, 1994-10)
      This paper analyzes the probability of bit error for PCM-FM over a standard IRIG channel subject to multipath interference modeled by the aeronautical fading channel. The aeronautical channel model assumes a mobile transmitter and a stationary receiver and specifies the correlation of the fading component. This model describes fading which is typical of that encountered at military test ranges. An expression for the bit error rate on the fading channel with a delay line demodulator is derived and compared with the error rate for the Gaussian channel. The increase in bit error rate over that of the Gaussian channel is determined along with the power penalty caused by the fading. In addition, the effects of several channel parameters on the probability of bit error are determined.
    • Processing Real-Time Telemetry with Multiple Embedded Processors

      BenDor, Jonathan; Baker, J. D.; Dovetail Systems Corporation; SEMCO (International Foundation for Telemetering, 1994-10)
      This paper describes a system in which multiple embedded processors are used for real-time processing of telemetry streams from satellites and radars. Embedded EPC-5 modules are plugged into VME slots in a Loral System 550. Telemetry streams are acquired and decommutated by the System 550, and selected parameters are packetized and appended to a mailbox which resides in VME memory. A Windows-based program continuously fetches packets from the mailbox, processes the data, writes to log files, displays processing results on screen, and sends messages via a modem connected to a serial port.