• PROBLEMS AND SOLUTIONS FOR NONSYNCHRONOUS TELEMETRY AND DATA SYSTEMS

      Grant, Eugene N.; Martin Marietta Orlando Aerospace (International Foundation for Telemetering, 1984-10)
      The modern pulse code modulated (PCM) telemetry or data transmission system should have its input data rates synchronized by its own, or an external clock. Either arrangement allows all pulsed input data to arrive in a known clocked time sequence. Data transmission is orderly, and all input and output gating occurs at required time intervals. Events in nature do not always follow an ordered sequence, but data transmission requires the pattern and order found in a synchronous system. Today’s missiles and aircraft do not always have the nicety of synchronous systems. In many systems today, the PCM will run at one clock rate, while the navigational computer will be set to a second rate, the autopilot processor at a third and the weapons handling system at a forth. In the slower data use systems such as “1553", data can be stored, deleted, refreshed, and data buffers or memory used. Output data loss is not too important, since output data use rates are well below input data rates. However, research and development aircraft and missile test flight applications require real time or at least time-tagged data. Transient responses cannot be lost because of clock skips or phase differences between clocks. This paper will review and explain data loss through clock skips or phase differences. The paper will show causes and effects with real time flight systems that have flown recently. Solutions such as direct synchronization, phase locked loops between separate clocked systems, and sample and hold first-in, first-out buffers, will be discussed. The applications and limitations of these solutions will be described. A development nonsynchronous system for a flight missile will be reviewed, showing block diagrams, component utilization, circuit schematics, and command application interfaces and software. The intent of this paper is not to give ultimate solutions to the clock synchronization problem, but to alert the telemetry system designer to this data problem. The paper will help define his solutions before he finds his data lost, missing or scrambled on flight test records.
    • IN-BORE TORSIONAL IMPULSE MEASUREMENT IN AN ARTILLERY PROJECTILE

      McGOWAN, JOSEPH T.; SMITH, HARRY G.; CHUNG, KOK Y.; ARMAMENT RESEARCH AND DEVELOPMENT CENTER (International Foundation for Telemetering, 1984-10)
      Torsional impulse is a phenomenon recently recognized by the artillery projectile community as an important design criteria for large caliber weapon systems. In 1976, an investigation on the in-bore motion of gun launched projectiles was initiated after the failure of a threaded joint in an 8 in. rocket assisted projectile. The failure prompted various attempts by projectile designers to characterize the torsional environment that caused the mechanical failure of the joint. Experiments were conducted using the wire-in-bore technique to provide transmission between the instruments on board the projectile and data acquisition ground station. Due to the high set-back and lateral forces, extraneous responses contained in the recorded signals made analysis of the data extremely difficult. Subsequently, the Technical Support Directorate and Large Caliber Weapons Systems Laboratory of the Armament Research and Development Center developed a telemetry projectile system (presented at the 1983 ITC Conference) capable of measuring torsional impulse phenomenon in a gun launch environment. This paper will correlate test data obtained from the first firing with the TM projectile to the response of the projectile in the tube. The accuracy of the data will be independently verified by external measurements and compared with experiments performed by Sandia Laboratories (Fig. 1). Finally, weapon design parameters that could affect the magnitude of torsional impulse and recommendations on how to minimize the potential hazard of this environment will be discussed.
    • A ONE-WAY DATA LINK OPERATING WITH EXTREME WEAK SIGNALS

      Goebel, Walter; DFVLR - German Aerospace Research Establishment (International Foundation for Telemetering, 1984-10)
      For maritime applications of distress communications via geostationary satellites a special method of signal processing was developed, called superposition technique. The data frame containing the alert message is transmitted from a distress equipment repeatedly. After being relayed by the satellite the signal is detected and improved by superimposing the frames. Around 14 dB is the actual processing gain. Thus a distress buoy is able to transfer a message from all over the world with high reliability by only transmitting a power of 50 mW omnidirectionally over a slant range of about 40 000 km. The described system, called the Distress Radio Call System (DRCS) was tested in a Coordinated Trials Program (CTP) of 6 nations. Both in a simulation phase and in a field test under exactly the same environmental conditions the DRCS with its superposition technique was able to detect signals with lowest signal-to-noise-density ratio without error. In laboratory tests using GAUSS channel conditions, a system threshold of 13 dB-Hz could be demonstrated. In a real environment (North Cape) 15 dB-Hz was the lower limit for error-free reception. CCIR approved a recommendation in June, 1984 for a system operating through geostationary satellites at 1.6 GHz being a DRCS-type with very little modifications.
    • TRENDS IN GERMAN TELEMETRY SINCE THE 50’s

      Mayer, G.; DFVLR-German Aerospace Research Establishment, Applied Data Systems Div. (International Foundation for Telemetering, 1984-10)
      The paper gives a short history of the beginnings in tele-meteorology and missile telemetry in Germany and describes the developments since the 50’s in these fields, and in remote control systems up to the present day.
    • CALCULATING RMS VALUES FROM DIGITAL AND SAMPLED DATA

      Rieger, James L.; Birch, Kent N.; PE/PTBW; Naval Weapons Center (International Foundation for Telemetering, 1984-10)
      The root-mean-square (RMS) of the amplitude of a waveform is defined for continuous data. When sampled data is used, the signal may be converted to a continuous analog signal, filtered, and the RMS value measured by traditional means; if, however, the data exists already in sampled digital form, the RMS value can be calculated on the sampled data itself. By so doing, moreover, the lower integration limit and the integration interval can be varied to provide better frequency response and/or accuracy. A computer program in BASIC is shown for demonstration purposes which may be spliced into a larger data analysis program.
    • EHF SOLID STATE POWER AMPLIFIER DESIGN FOR EXTENDED MISSION LIFE

      Edwards, John; deGruyl, J.A.; Asmus, Julius R.; LNR Communications, Inc. (International Foundation for Telemetering, 1984-10)
      Recent developments at LNR have demonstrated practical solid state power amplifier (SSPA) configurations capable of generating 20 watts pf CW RF power with a 5% bandwidth at 20 GHz. The driving force behind these developments is the need for a reliable, cost effective SSPA deployment on spacecraft, consistent with a ten year and greater mission life. The operational life of the SSPA will be described in terms of (1) minimum acceptable output power, (2) system redundancy and (3) SSPA active device lifetime. The singular and combined effects of the defined categories on the SSPA operational life are examined. More specifically, the various aspects of a power backoff capability of the modular power amplifier design as they relate to system reliability are discussed and graphically demonstrated. The availability of gallium arsenide impact ionization avalanche transit time (IMPATT) diodes with proven performance and reliability has been responsible for the development and manufacture of high power, reliable solid state amplifiers from X-band to Q-band. Based on preliminary accelerated life test data of unscreened devices and a 1dB power reduction, an IMPATT diode reliability of < 50 FITs is projected, substantially exceeding a ten year mission life. IMPATT diode characteristics, and reliability design considerations and performance of power amplifiers at 20 GHz will be described.
    • A MICROPROCESSOR CONTROLLED PARACHUTE DEPLOYMENT SYSTEM

      Turner, Donald G.; Naval Weapons Center (International Foundation for Telemetering, 1984-10)
      In the design and development of parachutes for recovery systems (missile, test vehicle, drone, etc.) there is a need for accurate controls and measurements during testing. Relations between air speed, air density, opening forces, and drag can only be determined in a dynamic environment. Through the use of microprocessors and programming flexibility, parachute design parameters can evaluated. Improved signal to noise characteristics are obtained through error analysis and compensation techniques. The incorporation of microprocessors has become a key element in the accurate control and measurement of parachute design parameters for recovery systems.
    • INFRARED LIGHT AND BIOMEDICAL TELEMETERING IN EUROPE

      Bornhausen, M.; Matthes, R.; Kimmich, H. P.; Univ. of Nijmegen; Bundesgesundheitsamt (BGA); Umweltforschung (GSF) (International Foundation for Telemetering, 1984-10)
      The applicability of telemetering devices in patient care and biomedical research is extended by the introduction of infrared (IR) light communication techniques. Research in this field demonstrated a particularly interesting potential for a multichannel/multipatient monitoring system comprising stimulation, remote control of physiological functions or drug delivery, and patient location. Compared to radiofrequency links IR-telemetry features distinct advantages, i.e. a wide transmission bandwidth which is not restricted by any government regulations, no interference with identical systems in adjacent rooms, no connector or antenna problems, and a cost-saving simple generation and detection of IRcarriers. Examples of recent laboratory and industrial developments are described.
    • A TELEMETRY SYSTEM FOR MEASURING STRESS IN A HIP JOINT PROSTHESIS

      Postal, R. B.; Boreham, J. F.; California Institute of Technology (International Foundation for Telemetering, 1984-10)
      It has been clinically observed that a significant fraction of hip joint implants fail due to mechanical loosening, particularly in younger, more active patients. Design enhancements are hampered by the lack of in vivo data of the actual forces produced on the prosthesis by various recipient activities. This paper describes a telemetry system small enough to fit in the spherical ball joint of a hip joint prosthesis. The system is capable of transmitting sufficient in vivo data to allow reconstruction of major forces through the prosthesis. The design allows for total hermetic enclosure of the electronic parts within the prosthesis which is implanted within the human body. Figure 1 shows 2 engineering model prosthesis assemblies. Input power coupling is provided through a cuff temporarily placed over the area of the device. Telemetry readout from the transmitter antenna, also totally enclosed, allows periodic out-patient checkup and monitoring. In this manner, since no batteries are used, in vivo monitoring of load forces on the prosthesis can be accomplished periodically over a several year period without surgical revision. The data obtained will be used to design stronger implants which will have very low failure rates even when subjected to activities of younger recipients.
    • AN OVERVIEW OF THE GPS DEMONSTRATION PROGRAM FOR RANGE APPLICATIONS

      Knoernschild, Gene F.; Rockwell International (International Foundation for Telemetering, 1984-10)
      This paper describes a program to evaluate the use of an integrated GPS/INS system as the source of Time/Space/Position for participant tracking in range applications.
    • A MISSILE INSTRUMENTATION SYSTEM DESIGN APPROACH

      Davis, Chuck; Penharlow, David; General Dynamics Convair Division; Aydin Vector Division (International Foundation for Telemetering, 1984-10)
      Requirements and design constraints of a missile instrumentation system are identified. These considerations were applied and a programmable master/slave PCM encoder with integral signal conditioning was selected for a major classified missile program. The engineering philosophy and hardware selected for this application are presented in this paper.
    • DATA LINK FOR GPS RANGE APPLICATIONS PROGRAM

      Baldwin, Richard G.; Macdonald, Thomas J.; The Analytic Sciences Corporation (TASC) (International Foundation for Telemetering, 1984-10)
      The Range Applications Joint Program Office (RAJPO) was formed to develop a family of NAVSTAR Global Positioning System (GPS) range equipment for the Tri-Service national test range community. TASC has supported the RAJPO in analyzing the potential use of GPS-derived Time Space and Position Information (TPSI) in test and training range activities, developing functional and performance parameters for a family of GPS range equipment, and aiding in the resolution of technical issues. This paper describes the Data Link System (DLS) which will be an integral part of the proposed GPS range instrumentation system. The DLS provides a means to transfer GPS-derived TSPI data from multiple vehicles to a central location. The major focus of the paper is on defining the DLS performance requirements to the detailed parameter level. A description of the data link operations is also included to provide insight into the functions of each of the US components.
    • GRUMMAN’S AUTOMATED TEST SYSTEMS

      Schiano, C.; Grumman Data Systems (International Foundation for Telemetering, 1984-10)
      Since the late 60’s, the Grumman Automated Test System (ATS) has supported test data processing on almost all of Grumman’s test programs. Derivatives have been adapted to other DoD programs and installed at Air Force and Navy test installations. This technical paper will briefly describe the original system (1969-1983), the present configuration (1983-1986) and the future configuration (1986-1990’s) of the ATS. The ATS at Grumman, is one of the industry’s longest lasting operational system for real-time aircraft testing, and will continue to be operational through the 1990’s.
    • DEVELOPMENT OF A WIDEBAM HIGH "C’ TELEMETRY SYSTEM FOR THE SADARM 8" PROJECTILE

      Longo, Salvatore; Anderson, David E.; Naber, Hildi S.; HQ US Army Armmnent Research And Development Center (International Foundation for Telemetering, 1984-10)
      A definite need existed for a high frequency, wideband, modular telemeter. This challenge was met with the development of two state-of-the-art projectile telemeters proven in support of the SADARM program. With the employment of existing gun proven designs, components, and software, two unique modular telemeters were designed. The modular design greatly facilitated testing and repair of these telemeters. Rail gun qualifying tests prepared these telemeters for use in high G environments. These gun rugged telemeters can withstand setback accelerations in excess of 12K G’s. Salient features of these telemeters include the use of numerous non-standard high frequency VCO’s, and a state-of-the-art transmitter with large deviation and data transmission capabilities. Emphasis is also given to design and application of a dual-van signal acquisition scheme. Deep nulls in the transmission antenna pattern were minimized with the employment of two receiving vans and an RF RERAD link between the vans which thereby enhanced transmission reliability. The scope of this paper includes an RF link analysis of the telemetry field test configuration. The facets elaborated upon include modular design, support software, and an in-depth electrical subsystem analysis. The major advantages of these telemeters is the employment of high frequency VCO’s with multi-channel capability for numerous simultaneous high frequency measurements.
    • TRACKING STATION INTEROPERABILITY

      Krenek, D. A.; The Aerospace Corporation (International Foundation for Telemetering, 1984-10)
      The DoD is focusing considerable attention on interoperability and internetting as effective means of increasing the survivability of space systems. The tracking stations of the various DoD space systems are prime candidates for interoperability and internetting enhancements for two reasons: (1) a belief that the “front ends” of the various ground command and control segments is where the greatest commonality of functions should already exist; and (2) the knowledge of the large existing DoD capital investment in tracking station assets. This paper provides a method for examining the similarities and commonalities among tracking stations and for identifying incompatibilities and differences which, if eliminated, would facilitate interoperability and internetting and, hence, improve the survivability of DoD space systems.
    • APPLYING TELEMETRY THEORY TO THE REAL-WORLD

      LAW, EUGENE L.; Pacific Missile Test Center (International Foundation for Telemetering, 1984-10)
    • ANALYTICAL STUDY ON BIT-SYNCHRONIZATION PROBLEMS IN A CODED COMMUNICATION SYSTEM

      Ng, Wai-Hung; The Aerospace Corporation (International Foundation for Telemetering, 1984-10)
      Many bit-synchronization techniques in digital communications depend on bit transitions for successful operation. In this paper, we first categorize the four main sources of generating transitionless signals. Then we describe general properties of channel coding and explain that, by injecting a well-selected detectable error pattern into the transmitted and coded signal, this bit transitionless problem can be eliminated without any additional bandwidth penalty. Finally, examples in both block code and convolutional code are selected for illustrating this simple but useful application.
    • A LOCALLY PROGRAMMABLE/NONVOLATILE WORD SELECTOR FOR DISPLAY OF TAGGED TELEMETRY DATA

      Duffy, Harold A.; Naval Weapons Center (International Foundation for Telemetering, 1984-10)
      The introduction of Data Compressors into the NWC Telemetry Ground Station has created the opportunity to circumvent usage of data distribution patch panels. An array of Word Selectors can be used to capture telemetry data parameters by tag identification for display on chart recorders. Design goals in the development include: independent operation, resident program storage, variable word length handling, and accommodation of nonstandard data formats. A prototype has been constructed and tested.
    • RECORDING PSK ON A ROTARY HEAD RECORDER

      Morgan, David P.; Datatape Incorporated, a Kodak Company (International Foundation for Telemetering, 1984-10)
      The paper presents a technical overview of recording predetection data such as PSK, QPSK and QPRS on a DATATAPE developed 8MHZ wideband instrumentation rotary head recording system. Included is a technical description and signal characteristic of the recorder as well as a summary of the test results of the predetection and post detection data.
    • HIGH DENSITY DIGITAL RADAR RECORDING SYSTEM

      LEUNG, VICTOR; DATATAPE INCORPORATED (International Foundation for Telemetering, 1984-10)
      EGLIN AFB, Armament Division, had initiated an ongoing update efforts to replace the obsolete video recorders and associated digitizing capability used to record radar signature data. The prime objective of this program was realized and has demostrated the feasibility of HIGH DENSITY DIGITAL RECORDING, as a means of radar video recording and has developed the interface design criteria for all radar sites at EGLIN AFB. The HIGH DENSITY DIGITAL RECORDER/REPRODUCER system had been adapted for radar use with a micro-processor driven radar interface unit that includes the following: A/D and D/A Converters, Input and Output formatter, Memories, Filtering Networks and Error Detection and Correction (EDAC), Auxiliary data mux and demux. The System has four modes of operation with a digitizing rate of 30 Mega-samples and a selectable 6, 7 or 8 bit resolution. The four modes are: Single radar channel, Dual radar channel, PRI sequence and Snapshot memory.