Burk, Martin R.; Sandia Support Operations (International Foundation for Telemetering, 1986-10)
      The Nevada Test Site Seismic Network, designed and operated by EG&G Energy Measurement, Inc. for Sandia National Laboratories, consists of five remote stations and one control point station. The system converts analog signals from five seismometers at each station to digital signals and multiplexes the data with status information for transmission over voice-grade telephone circuits to the control point at the Nevada Test Site. Intelligent modems provide automatic line equalization, transmission link diagnostics, and loopback testing. A microprocessor at the remote stations periodically refreshes the seismometer system gain settings to ensure data accuracy. The remote stations operate unattended and receive commands for setup and status check from the control point. The control point station utilizes a Digital Equipment Corporation (DEC) LSI-11/23 to perform event detection on the five data streams and automatically records up to ninety minutes of event data per station. Planned upgrades include replacing the LSI-11/23 with a DEC MicroVAX-II and implementing dialup capability to verify station status.

      MOHAN, A.; HINDUSTAN AERONAUTICS LTD. (International Foundation for Telemetering, 1986-10)
      One of the fastest methods of flight testing prototype aircraft and other aerospace vehicles is to use real-time tele-links. This method, has cutshort flight development cost, time and effort considerably. However, there are certain shortcomings in this methodology, such as, limited range, multipath effects, capability to test only one aircraft at a time, using auto-track systems, limiting the scene of activity to one centre etc. Opening other flight test centre in the country would mean duplication. With the daunting prospect of flight testing supersonic fighter aircraft in the 90’s, it becomes necessary to think of alternatives. This presentation describes a synchronous satellite system concept, as a suitable alternative for the Indian environment. It is concluded that in the Indian context, an operational system based on this concept is absolutely feasible and that a follow-up system would be a Domestic MILSAT communication network that apart from serving the flight test needs, meets the service requirements of other military aeronautical agencies in India.

      Cumming, Colin J.; Hoy, Leslie D.; Frontier Engineering, Inc. (International Foundation for Telemetering, 1986-10)
      This paper describes a microprocessor based multi-channel signal analyzer system for use with telemetry system pre- and post detected video signals. In the application described here, the system software is configured to simultaneously analyze up to 16 telemetry signals, compute an estimate of the SNR for each, and then select the best for output to real time recording equipment. The SNR is estimated by comparing the total signal energy with the signal power observed in an unused portion of the signal spectrum. The signal analysis filters are fully programmable over a range of 10 KHz to 2 MHz and may be set up to analyze a wide variety of telemetry formats. The microprocessor system also supports printed output of signal status and remote programming.

      Jenkins, George; Network Station, Merritt Island (International Foundation for Telemetering, 1986-10)
      Prelaunch, launch, mission and landing distribution of RF and hardline uplink/downlink information between space shuttle orbiter/cargo elements, tracking antennas, and Control Centers at JSC, KSC, MSFC, GSFC, ESMC/RCC, and Sunnyvale are summarized with emphasis on techniques currently used and planned future improvements. Color Vugraphs showing the 20 facilities involved and system block diagrams are used to reinforce the written text. Presentation is unclassified.

      HOBBIE, JOHN; SPACE DATA CORPORATION (International Foundation for Telemetering, 1986-10)
      Engineers developing specialized telemetry systems do not always have the vantage point of the user of their systems. The requirements of an upper air sounding system may seem straightforward at first; but, when the meteorologist’s viewpoint is considered, the engineering problems become more difficult than originally perceived. This paper discusses the Meteorological Data System (AN/GMD-5) manufactured by Space Data Corporation for the U.S. Air Force. The GMD-5 is designed to be a militarized, rugged, portable replacement of the World War II vintage GMD-1. It can be set up in the field and provide automatic, real-time data reduction of a rawinsonde flight within two hours of arrival at a site. The system has an extensive self-diagnostic capability such that a trained meteorological operator could troubleshoot faults and correct them down to the circuit board level. This paper presents the problems involved in designing a telemetry system that will work in field environments and will be easy to use by meteorological technicians. The whole system, including the sonde (both sensors and telemetering system), the tracker, telemetry decoder, and data processing systems, is presented, and the problems associated with the system’s performance and accuracy are discussed from the meteorologist’s point of view, followed by the engineer’s solution to these problems.
    • Generic Transaction Message Interface for Operations of Communication Networks

      Byrne, Charles J.; Bell Communications Research, Inc. (International Foundation for Telemetering, 1986-10)
      Transaction messages are those which control action at a remote point. They are used in communication networks for such functions as surveillance of alarms, performance monitoring, administration of data bases and tests of leased circuits. Generic interface requirements permit full compatibility of a wide range of telecommunications equipment with common operations systems. The specifications cover all aspects of the interface, from connectors to messages. Existing commercial standards are used where appropriate, including those of the Open System Interconnection (OSI) model. This paper covers the methods used to define the requirements and reports on the status of work in various standards groups.

      Cox, Timothy F.; Stanford University (International Foundation for Telemetering, 1986-10)
      A simple adaptive algorithm is employed in the determination of operating parameters for a sequential probability ratio test (SPRT) type of PCM frame synchronizer. Performance data over a wide range of bit error rates are obtained by computer simulation. These data show a significant improvement in lock-to-search transition performance of the SPRT over the so-called conventional type of synchronizer.

      Moller, Erhard; Bernstein, Lutz; Labor fur Nachrichtechnik, Fachhochschule Aachen (International Foundation for Telemetering, 1986-10)
      The safety of winter road traffic demands efficient winter maintenance. The highway authorities should be able to salt the roads just before the formation of ice. On the other hand the use of salt should be minimized because salt burdens the environment and the budget. A SLIPPERINESS EARLY WARNING SYSTEM for detection and prediction of ice should assist the highway authorities. The following four kinds of ice and their causes are of interest: *black ice/glazed ice: rainfall on undercooled road surface, *frost: freezing moisture on slowly cooling down road surface *advection dew: sublimation of warm air on undercooled road surface *compact snow : pressured snow. The system should permit two options: - warning system for the driver, - measuring system for the general weather forecast. The temperature, humidity and precipitation must be tested at dangerous places such as bridges, slopes and ridges. The road surface conditions such as temperature, covering, and degree of moisture and the amount of salt must be inquired about at several points at a dangerous place. The dates of weather and road conditions are to be transmitted from the dangerous place to a switching point over a distance of 10 km by a 2-wire-line. The test equipment for up to 10 places is connected to the same line. The data are transmitted by a pulse telemetry system from the switching point to local and central authorities. Since there is generally no power supply along the roads and highway except small power for telecommunication, the SLIPPERINESS EARLY WARNING SYSTEM has to operate with a power of 10 W/ 10 V DC for the 10 test equipments and transmitters along the 2-wire-line. This is a very hard condition in relation to using traditional sensors that need power for heating to prevent icing. Therefore some new sensors are developed and the sensors, the electronic equipment, and the transmitter are pulsed every 5 minutes. Air temperature and humidity are tested by sensors that are used by the weather forecast services. A new COMPACT SENSOR is developed to determine the road surface data. Additionally, an INFRARED SENSOR detects the state of the road surface. The analog voltages of the sensors are transmitted by an ANALOG MULTIPLEXER to an ANALOG DIGITAL CONVERTER. The digital data of weather and road conditions are transformed to a FSK signal and transmitted. A 8085 MICROCOMPUTER controls testing, data processing, signal transforming, transmitting, and timing at the dangerous place. The local and central authorities will have data and alarm presentation by a PC graphic display.

      McConnell, John B.; Baker, Robert L.; Flowers, Harold; Western Space and Missile Center; ITT-Federal Electric Corporation (International Foundation for Telemetering, 1986-10)
      The Western Space and Missile Center (WSMC) plans to precisely synchronize remote instrumentation site timing on the Western Test Range (WTR) using Global Positioning System (GPS) equipment being developed for Tri-Service range applications. This paper describes background information, current WTR timing capability, remote site synchronization requirements, a proposed GPS timing system configuration, and testing approach.

      Sulecki, Joan M.; Lerner, Theodore; LTV Aerospace & Defense Co. (International Foundation for Telemetering, 1986-10)
      A major factor in the performance of a Telemetry System over the sea is the effect of multipath. The reflected signal from the surface of the sea may, in general, add to or subtract from the direct signal, and may therefore lead to severe fading and possible loss of useful signal. The multipath is a function of the sea state and the polarization of the signal. In order to reduce the effect of multipath on performance, a dual polarization diversity system is being built for the Airborne Telemetry Relay System for the Gulf Range. An analysis of the performance of the dual polarization diversity system in the presence of multipath for different sea states, different reflection angles, and different initial polarization angles is presented. For comparison, a similar analysis is presented for a circular polarization receiving antenna system.

      PIETERS, BERNARD; DIRECTION DES ESSAIS (International Foundation for Telemetering, 1986-10)
      The development of ballistic missiles and launch vehicles in the last twenty five years has required the engineering, perfecting and introduction of suitable testing and measuring facilities, more particularly telemetry equipment. We purpose to recall the major milestones of the evolution in this field of techniques throughout that period and to try to define some prospects for the future. We do not pretend to give a historical account, but only our thought on an industrial experience that we have lived through. Therefore, we entreat the reader’s indulgence for the non-exhaustive character of this paper and perhaps for some unintentional errors or distortions.

      Kumar, Rajendra; California State University (International Foundation for Telemetering, 1986-10)
      A new least squares algorithm is proposed and investigated for fast frequency and phase acquisition of sinusoids in the presence of noise. This algorithm is a special case of more general adaptive parameter estimation techniques. The advantages of the algorithms are their conceptual simplicity, flexibility and applicability to general situations. For example, the frequency to be acquired can be time varying, and the noise can be non-gaussian, nonstationary and colored. As the proposed algorithm can be made recursive in the number of observations, it is not necessary to have a-priori knowledge of the received signal-to-noise ratio or to specify the measurement time. This would be required for batch processing techniques, such as the Fast Fourier Transform (FFT). The proposed algorithm improves the frequency estimate on a recursive basis as more and more observations are obtained. When the algorithm is applied in real time, it has the extra advantage that the observations need not be stored. The algorithm also yields a real time confidence measure as to the accuracy of the estimator.
    • TABS - an Asynchronous Block Serial Protocol for Multipoint Applications

      Schachter, Paul J.; AT&T Bell Laboratories (International Foundation for Telemetering, 1986-10)
      Since the early 1960’s, AT&T has established a trend toward centralized and remote operations of the transmission network. Thorough and continuous monitoring of global network properties can only be achieved through centralization. As a result, a secondary network has evolved in support of these monitoring functions. The “telemetry network” comprises a system of distributed processors dedicated to analyses of the transmission network, together with all necessary communication links. Monitoring access to the transmission network is provided at special interface points. Often the interface hardware is integrated into the transmission network element itself. AT&T uses a special protocol, TABS, the Telemetry Asynchronous Block Serial protocol, at the interface between the telemetry network and the transmission network.[1] TABS was designed by AT&T Bell Laboratories to optimize the performance and economics of this interface. In this paper, we describe the structure of that protocol, its performance properties and current implementations.

      Davis, Edward L.; Grahame, William E.; Loral Instrumentation (International Foundation for Telemetering, 1986-10)
      When flight testing helicopters, it is essential to process and analyze many parameters spontaneously and accurately for instantaneous feedback in order to make spot decisions on the safety and integrity of the aircraft. As various maneuvers stress the airframe or load oscillatory components, the absolute limits as well as interrelated limits including average and cumulative cycle loading must be continuously monitored. This paper presents a complete acquisition and analysis system (LDF/ADS) that contains modularly expandable array processors which provide real time acquisition, processing and analysis of multiple concurrent data streams and parameters. Simple limits checking and engineering units conversions are performed as well as more complex spectrum analyses, correlations and other high level interprocessing interactively with the operator. An example configuration is presented herein which illustrates how the system interacts with the operator during an actual flight test. The processed and derived parameters are discussed and the part they play in decision making is demonstrated. The LDF/ADS system may perform vibration analyses on many structural components during flight. Potential problems may also be isolated and reported during flight. Signatures or frequency domain representations of past problems or failures may be stored in nonvolatile memory and the LDF/ADS system will perform real time convolutions to determine the degrees of correlation of a present problem with all known past problems and reply instantly. This real time fault isolation is an indispensable tool for potential savings in lives and aircraft as well as eliminating unnecessary down time.

      Jeske, Harold O.; Sandia National Laboratories (International Foundation for Telemetering, 1986-10)
      An increase in the maximum power flux-density (pfd) permitted from satellites in the 2025 to 2300 MHz band is currently under consideration by IRAC. This analysis assumes the worst case conditions for interference to telemetry operations at the missile test ranges as a result of current and proposed satellite pfd levels. Assumptions in the analysis include the maximum permitted power flux-density with uniform energy distribution over the band of interest, polarization compatibility, and alignment of the telemetry station, the missile and the satellite. It was found that the performance of essentially all missile telemetry receiving systems may be appreciably degraded by even the lowest pfd limits currently permitted. For the higher pfd limits under consideration, degradations in the order of 40 dB are to be expected at stations with dish antennas of only five foot diameter. An increase in the size or gain of an antenna will reduce the probability of interference, because of its decreased beamwidth, but will also increase the performance degradation because of the station’s increased figure of merit, G/T. For satisfactory missile telemetry operation under these conditions, the normal missile’s telemetry received signal-to-noise ratio would have to be well over 40 dB to overcome satellite interference. The results of the analysis are actually independent of all receiving station parameters except the station’s figure of merit, G/T. Probability of interference is not addressed because of the variation of conditions and missions of the various test ranges as well as the unknown number of satellites and their characteristics - present and future. If missile and satellite telemetry is to coexist in the 2200 to 2290 MHz band, the implementation of several recommendations is considered necessary. The recommendations are; 1) Satellite pfd levels should remain at the current limits; 2) Coordination between the satellite controllers and the range operations must be established; and 3) Multiple telemetry receiving stations with significantly different aspect angles with respect to the test vehicle during the test should be used.
    • International Telemetering Conference Proceedings, Volume 22 (1986)

      International Foundation for Telemetering, 1986-10

      Eccles, Lee H.; Muckerheide, John J.; Boeing Commercial Airplane Company (International Foundation for Telemetering, 1986-10)
      The Experimental Flight Test organization of the Boeing Commercial Airplane Company has an onboard data reduction system known as the Airborne Data Analysis/Monitor System or ADAMS. ADAMS has evolved over the last 11 years from a system built around a single minicomputer to a system using two minicomputers to a distributed processing system based on microprocessors. The system is built around two buses. One bus is used for passing setup and control information between elements of the system. This is burst type data. The second bus is used for passing periodic data between the units. This data originates in the sensors installed by Flight Test or in the Black Boxes on the airplane. These buses interconnect a number of different processors. The Application Processor is the primary data analysis processor in the system. It runs the application programs and drives the display devices. A number of Application Processors may be installed. The File Processor handles the mass storage devices and such common peripheral devices as the printer. The Acquisition Interface Assembly is the entry point for data into ADAMS. It accepts serial PCM data from either the data acquisition system or the tape recorder. This data is then concatenated, converted to engineering units, and passed to the rest of the system for further processing and display. Over 70 programs have been written to support activities on the airplane. Programs exist to aid the instrumentation engineer in preparing the system for flight and to minimize the amount of paper which must be dealt with. Additional programs are used by the analysis engineer to evaluate the aircraft performance in real time. These programs cover the tests from takeoff through cruise testing and aircraft maneuvers to landing. They are used to analyze everything from brake performance to fuel consumption. Using these programs has reduced the amount of data reduction done on the ground and in many cases eliminated it completely.

      Lingerfelt, C. W.; ITT-Federal Electric Corporation (International Foundation for Telemetering, 1986-10)
      The processing of telemetry data received at the Western Test Range (WTR) requires the use of user supplied measurement attributes information. The telemetry streams currently being presented for support are from technologically advanced test vehicles which often involve complex measurement definition schemes. This document describes some of the current definition schemes and the processing required to obtain and utilize the data. The chaotic state of this environment is in no small part due to the lack of standardization of the measurement definition scheme and its media. The trend has been, and will continue to be, a condition of ever increasing complexity and variety unless some standardization is applied.

      Sargeant, H.; Interstate Electronics Corporation (International Foundation for Telemetering, 1986-10)
      Predetection recording of spread-spectrum (SS) signals such as GPS transmissions is a desirable objective for both users and developers of equipment designed to receive such signals. (GPS user-equipment development is a lengthy process during which signal simulators are only partially useful.) Upon playback, GPS signals are used by the same or modified receivers so that acquisition, processing, detection and tracking loops can be altered to optimize the receiver parameters. Development of predetect SS signal recording systems is difficult to achieve in practice. Such systems not only must be of suitable phase linearity to preserve the signal content to be extracted but sometimes must also preserve the exact signal-to-noise ratio (SNR) characteristics of the recorded signals. Existing conventional test equipment is unsuitable for deriving value judgments of the quality of a predetect recording system’s output because the SS signal has a negative SNR. This paper reveals that it is possible to use, for this purpose, tape recorders now available on many test ranges in combination with auxiliary equipment similar to that designed for the U.S. Navy’s TRIDENT Program (recording C/A-code data from in-flight missile translators). The basic techniques are described in some detail to enable potential users to understand the necessary equipment concepts and evaluate the author’s approach in terms of their own applications.

      Mohanty, Nirode; The Aerospace Corporation (International Foundation for Telemetering, 1986-10)
      The performance is presented of a spread spectrum communication system utilizing binary phase shift keying (BPSK), differential binary phase shift keying (DBPSK), and 8-ary frequency shift keying (FSK) signals in the presence of partial band jamming noise and tone noise. A combination of coding, interleaving, and diversity techniques provides the best antijamming capability.