Diebel, Dean L.; Recovery Systems Instrumentation Branch (International Foundation for Telemetering, 1984-10)
      In the development and design of parachutes, select data parameters are required for evaluation. These parameters give the designer dynamic information in actual environments providing stress, load, and glide ratio information. At present this information (altitude, rate of descent, total velocity, acceleration, dynamic pressure and attitude), is obtained by the use of space positioning methods. Meterological data, used to calculate some of these parameters, are obtained from rawinsonde balloons which are launched one half to two hours before and after the drop test. Typical combined data accuracies are on the order of plus or minus f ive percent with most of these errors being ascribed to the fact that the weather data is not taken at the time of the test and atmospheric conditions change rather quickly during the morning hours when the tests are typically done. A method has been developed which will measure meterological data real time. Direct measurements are taken via transducers ie. pressure, acceleration, attitude, temperature and humidity. These transducers are combined in the microprocessor circuitry to obtain final data prior to solid state recording or transmission. This paper will describe the methods and justifications for pursuing a different type of data gathering system.
    • A Programmable Data Acquisition System with Integrated Test and Calibration Facilities

      Zach, Adolf; Gandert, Rüdiger; Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt e.V. (DFVLR) (International Foundation for Telemetering, 1984-10)
      In 1985 the new Advanced Technologies Testing Aircraft System (ATTAS) will be operable at DFVLR Braunschweig. For this research aircraft a flexible, highly accurate and testable data acquisition system was developed. It consists of a modular and distributed microprocessor system with signal conditioning units situated near the sensors. It is controlled by a master unit with an integrated PCM encoder. The flexible signal conditioning featuring software-controlled parameters and adaptable signal inputs, can be tested automatically via the analog calibration bus using switchable signal paths. The system will be presented in detail and its performance will be shown by typical examples of application within ATTAS.

      Fickas, Ernest T.; Wadsworth, Isobel M.; SRI International (International Foundation for Telemetering, 1984-10)
      The Global Positioning (GPS), which is being developed by the DoD to support the operational forces, is a navigation aid that provides the user with precise position, velocity, and time information anywhere within line-of-sight of four satellite transmitters. It also holds potential benefits for use by the civilian community and the DoD test and training ranges. The differential navigation technique consists of using measurements from reference user equipment at a precisely known location to provide correction data to improve the navigation solution of a user equipment at an unknown location. The correction data consist of errors in position estimates derived from reference receiver output using the known true location coordinates. These data are applied to the output of the user equipment (at the unknown location) to remove common-mode errors due mainly to ionospheric propagation delays and satellite clock and ephemeris errors. Data were collected for user-to-reference separation distances of from zero to 280 nmi at night. Accuracies achieved do not confirm predictions of a degradation in efficacy of differential corrections with increasing separation distance; however, local disturbances at either GPS receiver cause considerable dispersion in the data.

      Seeley, Robert L.; Daniels, Jeffrey J.; U.S. Geological Survey (International Foundation for Telemetering, 1984-10)
      A system has been developed to simultaneously sample and transmit digital data from five remote geophysical data receiver stations to a control station that processes, displays, and stores the data. A microprocessor in each remote station receives commands from the control station over a single telemetry channel. The commands adjust the sensing amplifier’s input voltage range (1 microvolt to 2 volts peak-to-peak), the number of samples (128 to 30,000), the sampling rate (256 to 32,768 samples/sec), and the number of signals (1 to 16) to average at the remote stations. A 12 bit analog-to-digital converter samples data with bandwidths of 100 Hz to 10 kHz for time periods selected from 100 seconds to 1 second, respectively. Each remote station begins sampling geophysical signals when it receives a synchronizing pulse relayed from the control station. Digitized geophysical data is transmitted to the control station over broadband (100 kHz bandwidth) UHF telemetry channels using standard asynchronous serial (19.2 kbaud) techniques and hardware dropout detection and recovery. The amount of data (480 kbits) and the maximum time to transmit data (30 secs) dictate using broadband telemetry (even though most geophysical telemetry is less than 10kHz in bandwidth). Header information (transmitted before the data) contains station number, digital sampling parameters, transmission block size, and checksum. This information is used by a computer program (in a PDP-11/23 (***) minicomputer) to maintain up to 5 simultaneous Direct Memory Access (DMA) transfers from the remote stations into 5 separate data buffers. Filled buffers are transfered (via an IEEE-488 bus) to an interactive analysis and display system (HP9845C (***)) for selecting data to be stored on magnetic media for subsequent laboratory analysis.

      Avery, Lawrence G., Jr.; ARIA Programs Division (International Foundation for Telemetering, 1984-10)
      The topic of this paper is the history of ARIA from its beginning during the Apollo program to its current use as an airborne telemetry platform for orbital, ballistic, and cruise missile testing. The evolution of ARIA telemetry equipment from 1968 to the present will be discussed, as well as plans for future modernization and improved capability. Specific areas to he covered include: real-time data relay, pseudomonopulse tracking, onboard data processing, computer controlled tracking, new receivers, new recorders, and planned modifications to meet future requirements.

      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.

      Reinhard, Kenneth L.; Darlington, John C.; Ford Aerospace & Communications Corporation (International Foundation for Telemetering, 1984-10)
      Automated acquisition of a satellite’s downlink signal by the main beam of a ground station’s tracking antenna is complicated by the presence of antenna pattern sidelobes and potential large uncertainties in the spatial and/or frequency location of the signal. Sidelobe acquisition prevents autotracking and telemetry reception, and large uncertainties require time for coordinated antenna and receiver search. Use of an auxiliary antenna assists in resolving the sidelobe intercept problem, and a high speed digital receiver alleviates the problems associated with spatial and frequency uncertainty. The antenna and receiver, under processor control, constitute a fully automated system. The associated processor software controls the antenna motion during the search phase, selects the proper receiver configuration for the expected signal environment, makes the main beam versus sidelobe intercept decision and switches to autotrack mode upon successful signal acquisition.
    • Telemetry from Experimental Rescue- and Recovery Systems

      Klewe, Hans-Joachim; Institute for Flight Mechanics Braunschweig/Germany (International Foundation for Telemetering, 1984-10)
      Measuring techniques in rescue and recovery systems are mainly applied to parachute and ejection seat systems. Thereby, the measurements of special interest are: forces occuring in the suspension lines of parachutes during inflation; accelerations acting on persons to be rescued or on materials to be recovered; the progress of velocities during the retarding of persons, ejection seats, test verhicles and so on; as well as measurements of the static pressure and possibly the outside temperature for the determination of altitudes. Further, the change of the projected area of a parachute during inflation will also be of interest. The data values are transformed by the transducers to analogue electric signals and telemetered to the ground station. To determine the projected area of the parachute during inflation this event is filmed by a high speed film camera which is installed in the rear of the test vehicle. Furthermore, the entire experiment is filmed from the ground by another high speed camera. On request, a cinetheodolite and a tracking radar installation is used additionally to get data concerning rate of descent and trajectory of the parachute-load system. (1,2)

      Hammel, K.; Kienzle, W.; Standard Elektrik Lorenz AG (International Foundation for Telemetering, 1984-10)
      Communications is one of the most important markets all over the world for investment as well as for services in this area. Round about half of all employees of modern industrial societies are engaged in transmitting or processing informations.

      Schmalz, Axel; Kayser-Threde GmbH (International Foundation for Telemetering, 1984-10)
      The requirements for data acquisition systems grow rapidly with the progress of technology. Increasingly complex test instruments become available. Integration of instruments and computers into an operational measurement system, however, is more difficult and expensive as requirements increase. A family of instruments was developed which can perform complex measurement tasks without a large integration effort since it provides a large number of compatible hardware and software modules for conditioning and conversion of signals into digital form, for data storage, data transmission, and data pre-processing.

      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.

      Lewis, Malcolm L; ACROAMATICS, Inc. (International Foundation for Telemetering, 1984-10)
      Designing and constructing a real time telemetry system for unique applications can involve considerable time to evaluate, choose, acquire, and interface the necessary elements. The use of a highly versatile single chassis telemetry acquisition system can reduce or obviate the need for external pre- or post-processors as well as the potentially difficult hardware and software interfacing. It also results in an easily upgradable and generally modifiable system from the development phase, through delivery, and on site by both the designer and user. The basis of the system described here is a parallel/serial multiprocessor whose architecture is programmable.
    • Remote Control of an Impact Demonstration Vehicle

      Craft, James B., Jr.; Harney, Paul F.; Johnson, Richard G.; NASA Ames Research Center; Dryden Flight Research Facility (International Foundation for Telemetering, 1984-10)
      The Full Scale Controlled Impact Demonstration (CID) program is a joint NASA/FAA effort to test improvements in aircraft crashworthiness. Specifically, a transport aircraft was modified to be remotely piloted by telemetry control and flown into a “survivable” crash. On board was a fuel cargo of anti-misting kerosene (AMK) to inhibit post crash fires. Also, various measurements were made to examine crash structural response, and improvements in new seat and restraint design using instrumented anthropomorphic dummies. Mechanization of the remote uplink telemetry command system and the downlink data systems is described.

      Blackwell, Earl G.; Fickas, Ernest T.; Richardson, David Y.; SRI International (International Foundation for Telemetering, 1984-10)
      A GPS receiver with antennas located in an aircraft-mounted pod will be subject to signal blockage due to masking of the GPS satellite constellation by the aircraft structure. Analysis of aircraft flight test data involving a wing-mounted GPS antenna has shown that most of the receiver’s loss-of-lock occurrences can be correlated with the optical shadow of the aircraft. Shadow regions of various tactical aircraft are used to estimate the extent of tracking outages for GPS pod antennas with the full 18-satellite constellation.

      Freymann, Dieter; Messerschmitt-Bölkow-Blohm (MBB) Dynamics Division (International Foundation for Telemetering, 1984-10)
      A data transmission system using fibre-optics data links has been developed to determine the compatibility of weapon systems electro-explosive devices to radiated electromagnetic environments. The EED’s are instrumented with temperature sensors which are as sensitive to pulsed RF as to continuous wave RF. Significant progress has been made in reducing the RF coupling of the sensors and in decreasing size, weight and power consumption of the decentralized telemetry system. After the description of the system some examples of measurements are reported. In coordination with the Military Departments this specific data transmission system will become a Military Standard in the near future.

      Johns Hopkins University; Westerfield, Edwin E. (International Foundation for Telemetering, 1984-10)
      A method for determining position and velocity as a function of time is required in order to test many systems involving moving platforms, such as missiles or sonobuoys. The Air Force Global Positioning System (GPS) is ideally suited for providing this information. Limitations exist, however, in currently available receivers. They are expensive to use in expendable platforms, plus they require more volume and power than are typically available. An alternative is to use either a translator or a transdigitizer in the vehicle under test. The signals transmitted by the GPS satellites are received by antennas on the missile, translated to a frequency in the telemetry band, amplified, and transmitted to a receiving station. In addition, if a transdigitizer is used, the signal is digitized prior to transmission. Specially designed receiving equipment on the ground processes the transmissions from the translator/transdigitizer, tracks the transmissions from each satellite, and makes the measurements necessary to allow the computation of the platform position and velocity. These systems concepts will be discussed, and a system currently using a translator in a missile and a system using a transdigitizer in a sonobuoy will be described in detail.

      Wagner, Robert E.; Ford Aerospace & Communications Corporation (International Foundation for Telemetering, 1984-10)
      National defense strategies rely on force enhancement, space defense, space control and space force application functions being provided by survivable space resources. The ground command and control support for these functions must be at least equally survivable. An approach to meeting these ground survivability requirements is presented in this paper. A highly mobile satellite control system is presented incorporating recent technology advances into a modular design that satisfies a wide variety of user requirements in all levels of conflict. Ground/Air Transportability is enhanced significantly by the incorporation of monolithic phased arrays and miniaturized Tracking, telemetry and command (TT&C) equipment and data processing hardware. Hardness is enhanced by the incorporation of new materials and an advanced structural design that protects against EMP, blast thermal effects and terrorist activities. A preliminary design is described that indicates how modularity supports a spectrum of expected operating scenarios.

      Winslow, Roger G.; Winslow Consultants (International Foundation for Telemetering, 1984-10)
      The increased United States dependency on space systems for military operations has resulted in the need for major upgrades in the survivability of our space systems in both the space and ground segments. Achievement of this survivability upgrade is in turn dependent on the exploitation of new technologies across a broad spectrum of disciplines. This paper will focus on the technologies which must be considered for enhancing the survivability of the space mission ground segment. Technologies to be discussed will include nuclear hardened mobile terminals, rapidly deployable multiple frequency antennas, ranging from S-Band to EHF, A-J communications, standardization, application of VHSIC and VLSIC, Artificial Intelligence, simulation and built-in test.

      Hurd, William J.; Statman, Joseph I.; Jet Propulsion Laboratory, California Institute of Technology (International Foundation for Telemetering, 1984-10)
      A breadboard high dynamic GPS receiver capable of pseudorange tracking with accelerations of 50 g or higher without inertial aiding is presented. The receiver uses cross correlation followed by fast Fourier transformation to approximate maximum likelihood estimation of pseudorange and range rate, with no phase or delay locked loops. The breadboard system consists of a one channel receiver and a high dynamics signal simulator. A planned demonstration of the receiver is described and anticipated results are presented showing pseudorange lag errors of under 10 m with acceleration of 50 g.

      Pasek, G. E.; Lockheed Missiles and Space Corporation (International Foundation for Telemetering, 1984-10)
      The paper will summarize the approach and considerations being given to the development of a survivable Mission Control Segment. Satellites of the future need to be designed with control needs in mind and provided with a high degree of autonomy and intelligence. Earth based support must be designed around operators who are limited in skill and therefore rely on sophisticated software and a degree of Artificial Intelligence. The total system approach, progress, and findings for these future Space and Ground Systems will be presented during the 20+ minute overview discussion.