• PHASE CORRECTION AND PHASE CANCELLING NETWORKS IN QPSK MODEMS

      Uzunoglu, Vasil; Maiorano, Ann B.; Fairchild Industries (International Foundation for Telemetering, 1985-10)
      At bit rates lower than 100Mbit/s, the Synchronous Oscillator (SO) [1-4] has substantial tracking band combined with steep skirt selectivity to satisfy all the requirements of a carrier recovery network without the need for a phase correction network. At higher bit rates however, there is a need for a phase correction or phase cancelling network, if the BER variations with respect to hard wired case must be confined to less than 0.2dB with IF offsets of ±30kHz. At bit rates higher than 100Mbit/s, the multiply by four process in a QPSK modem deteriorates the signal-to-noise ratio by more than 15 dB (18dB at Eb/No = 6.4 dB) and the synchronization signal-to-noise ratio at the input to the SO drops below 0dB (!5dB at Eb/No = 6.4dB). This reduction in the signal-to-noise ratio reduces the tracking band of the SO which in turn increases the phase shift per unit frequency offset.
    • USER PROGRAMMABLE REAL-TIME PROCESSING IN MODERN TELEMETRY SYSTEMS

      Williamson, Gale; Loral Instrumentation (International Foundation for Telemetering, 1985-10)
      This paper describes a method for providing user programmability to telemetry ground stations. It describes the inadequacies of a traditional computer and proposes the use of a data flow architecture to meet real-time processing requirements. The general characteristics of data flow architectures are discussed along with the reasons why telemetry processing is a natural problem class to be solved using data flow techniques. Finally, the practical application of a Loral DATAFLO™ telemetry system is presented.
    • VLSI ORIENTED COMPUTER ARCHITECTURE AND SOME APPLICATIONS

      Tabak, Daniel; Boston University (International Foundation for Telemetering, 1985-10)
      The paper surveys the particular problems, arising in the architectural design of computing systems, realized on VLSI chips. Particular difficulties due to limited on-chip density and power dissipation are discussed. The difficulties of the realization of on-chip communications between various subsystems (between themselves and between other offchip systems) are stressed. A number of design principles for the realization of on-chip communication paths is presented. Two design philosophies for the instruction set design in a VLSI environment are brought up: (a) The large microcoded instruction set, (b) The Reduced Instruction Set Computer (RISC) approach, based on the Streamlined Instruction Set Design. A survey of the author’s research group work in this area is presented. This includes the ZT-1 single chip microcomputer, RISC computing space studies, applications to a distributed traffic control and a la rge scale, reconfigurable communications system.
    • NUMERICAL FUSION OF REDUNDANT TELEMETRY SOURCES

      PELLET, F.; AEROSPATIALE (International Foundation for Telemetering, 1985-10)
      During a flight test of a missile or a launcher, the emitted PCM telemetry messages are recorded in different receiving ground stations. Because of the small number of flight tests during development period, our main purpose will be to make the best deferred restitution - up to one bit - of all the on - board emitted informations, and this, with a round to one Megabits per second rythm and during a several minutes period.
    • ERROR CORRECTION FOR THE AMPEX DIGITAL CASSETTE RECORDING SYSTEM (D.C.R.S.)

      Handley, Kirk H.; Stenerson, Roger M.; Ampex Corporation (International Foundation for Telemetering, 1985-10)
      A digital tape recorder that supports bit rates of up to 107.5 Mbits/sec is described. The channel rate of 118 Mbits/sec is achieved by use of randomized NRZI recording with class IV partial response equalization and Viterbi detection. The system bit error rate without error correction and an analysis of burst error statistics is presented. The development of a Reed-Solomon error correcting code with very large interleave depth is discussed and details of its implementation are given. The bit error rate of the system after application of error correction is presented.
    • VISUAL PERCEPTION AND AI: AN ARTIST’S VIEW

      Berks, Robert; Berks, Dorothy M.; Halyoake Avenue (International Foundation for Telemetering, 1985-10)
      The creative process of the visual artist is an untapped source of knowledge-based systems which can extend the capabilities of AI in understanding how to develop new algorithms for space perception, pattern recognition, and data compression. This report focuses on the artist’s analysis of the multi-dimensional levels of unconscious, visual ideation which precede the conscious level of symbolic coding. interaction of all the senses is examined, as are the functions of gravity and time as the fundamental reference points for pattern recognition. An exercise in ‘Image Evoking’ is described. Recommendations are given for applications to future research in AI.
    • NAVSTAR-GLOBAL POSITIONING SYSTEM (GPS) FOR RANGE APPLICATIONS

      HANCOCK, THOMAS P; Joint Program Office (RAJPO) (International Foundation for Telemetering, 1985-10)
      The purpose of this paper is to describe the Tri-Service effort to use the NAVSTAR Global Positioning System (GPS) on Tri-Service ranges. It will describe the background, the development program, the equipment, the management team, the specifications that the equipment must satisfy, the integration into five DOD ranges, an assessment of developmental risk, a recap of logistical aspects, and will provide a development schedule.
    • DIGITAL RECEIVER PROCESSING TECHNIQUES FOR SPACE VEHICLE DOWNLINK SIGNALS

      Natali, Francis D.; Socci, Gerard G.; Stanford Telecommunications, Inc. (International Foundation for Telemetering, 1985-10)
      Digital processing techniques and related algorithms for receiving and processing space vehicle downlink signals are discussed. The combination of low minimum signal to noise density (C/No), large signal dynamic range, unknown time of arrival, and high space vehicle dynamics that is characteristic of some of these downlink signals results in a difficult acquisition problem. A method for rapid acquisition is described which employs a Fast Fourier Transform (FFT). Also discussed are digital techniques for precise measurement of space vehicle range and range rate using a digitally synthesized number controlled oscillator (NCO).
    • EFFECT OF CLOCK JITTERS ON BIT ERROR RATE

      Xianda, Dai; Rongfa, He; Man, Li; 202 Beijing Institute of Aeronautics and Astronautics (International Foundation for Telemetering, 1985-10)
      In this paper we have formulated a method of analysing the effect of clock jitters, which, even with the monomode optical fiber avaiable today, is still there to limit the operational distance of a digital fiber optic system. The main intention is to compare the system performance of a conventional binary system with that of a newly developed four-level pulse width modulation (PWM) system. Calculated results show an improvement in combatting clock jitters when using the four-level PWM system.
    • TSPI DATA PROCESSING IN THE TELEMETRY ENVIRONMENT

      Reed, Gary; Computer Sciences Corporation (International Foundation for Telemetering, 1985-10)
      Most test ranges are required to process both telemetry and Time Space Position Information (TSPI) data in real time. Using the Integrated Flight Data Processing System (IFDAPS) at Edwards AFB as an example, this paper identifies some of the basic differences between telemetry and TSPI data processing and discusses methods of integrating the two types of processing. Included for consideration in the integrated processing are data acquisition, measurement displays, recording, derived measurement computations using both types of data, and post flight merging of telemetry and TSPI data. Data processing is discussed in a concurrent, multiple operation environment using separate, integrated processors.
    • Real-Time Storage for Modern Telemetry Processing Systems

      Hollstien, Dave; Loral Instrumentation (International Foundation for Telemetering, 1985-10)
      With the ever increasing demands for higher data volumes and faster data rates, the real-time storage of data is consuming a vast majority of the conventional Telemetry system’s processing bandwidths. General purpose computers have traditionally shared the real-time functions of data storage and operator data and graphic displays. Although the power of the general purpose computer is increasing year-by-year, the telemetry data storage and display requirements are increasing at a far greater pace. Even the fastest host processors have proven incapable of keeping pace with these requirements. This paper will address an architectural approach to real-time storage that will relieve the host processor of this burden.
    • AN APPLICATION OF KNOWLEDGE-BASED SYSTEMS TO SATELLITE CONTROL

      Skiffington, Barbara; Carrig, Jim; Kornell, Jim; General Research Corporation (International Foundation for Telemetering, 1985-10)
      This paper describes an expert system prototype which approaches some issues of satellite command and control. The task of the prototype system is to assist a spacecraft controller in maneuvering a geosynchronous satellite for the purpose of maintaining an accurate spacecraft pointing angle, i.e. station keeping. From an expert system’s point of view, two features of the system are notable. First, a tool for automated knowledge acquisition was employed. Because the domain experts were in Maryland while the AI experts were in California, a means to automate knowledge acquisition was required. Second, the system involves a blend of simulation and expert systems technology distributed between a DEC VAX computer and a LISP machine (a special purpose AI computer). This kind of distribution is a plausible model for potential real-world installations.
    • RMPS A REALTIME PARALLEL COMPUTING SYSTEM

      TROVER, WILLIAM F.; Teledyne Controls (International Foundation for Telemetering, 1985-10)
      Research and Test Activities have a continuing need to cope with more and more channels of data and at continually wider data bandwidths. There is a consensus in the test community that compressed EU and derived parameter data presented in realtime can significantly reduce total test costs because test engineers can make realtime judgements on the validity of a given test point (mode). Classical telemetry preprocessors usually cannot handle these more demanding realtime processing requirements because, when they were designed, it was assumed that raw data was in a single PCM word and only a simple mx+b EU conversion, or simple data compression was required. Present preprocessors typically use special bit slice technology to speed up the realtime process and they’re only one or two bus systems whose processing capacity is typically less than 300k to 400k parameters per second. Furthermore, many cannot handle word concatenation (except for adjacent PCM words) and none can handle complex derived parameters such as thrust, lift, gross weight, center of gravity, stall speed, harmonic analysis, etc. To address these limitations, a massively parallel computer system has been developed based on up to sixty, general purpose, 1MFLOP floating point computers operating in parallel to support realtime processing of any type, at aggregate throughputs up to 1.5 Mwps. This system can merge realtime data from up to eight different asynchronous sources having word rates up to 2.0 Mwps from any source. Up to 32,768 different parameters can be accepted as inputs with an additional 32,768 ID tags available for concatenated and derived parameter identification. A powerful realtime software package permits the user of the computer system to apply any, or many algorithms) to any or an parameters being processed.
    • UNIVERSAL DATA COMPRESSION

      Lindsay, Robert A.; Cox, B.V.; Communications Corporate Technology Center (International Foundation for Telemetering, 1985-10)
      Universal and adaptive data compression techniques have the capability to globally compress all types of data without loss of information but have the disadvantage of complexity and computation speed. Advances in hardware speed and the reduction of computational costs have made universal data compression feasible. Implementations of the Adaptive Huffman and Lempel-Ziv compression algorithms are evaluated for performance. Compression ratios versus run times for different size data files are graphically presented and discussed in the paper. Required adjustments needed for optimum performance of the algorithms relative to theoretical achievable limits will be outlined.
    • REAL-TIME TELEMETRY OF COMPLETE 1553 DATA BUSES

      Breedlove, Phillip M.; Stephens, Charles R.; Loral Instrumentation (International Foundation for Telemetering, 1985-10)
      As MIL-STD-1553 Multiplex Data Bus usage proliferates, the ability to remotely monitor bus traffic has become important. Common applications include flight testing of missiles and aircraft, and the field maintenance of vehicles. Due to the high data rate and asynchronous characteristics of the 1553 Data Bus, special problems exist in the acquisition and analysis of 1553 bus traffic. The acquisition of the complete bus traffic is especially important during system testing and diagnostic operations. Several approaches are being utilized today to transmit 1553 bus traffic. The first approach is an extension of the PCM technique in which all of the bus traffic, during a specific time window, is buffered and then output in a PCM style format. This has the advantage of being synchronous, but a significant amount of bus information is lost, primarily the protocol and bus timing. An alternative approach is to transmit raw unbuffered bus traffic. Bus timing and protocol are retained, but the telemetry signal is asynchronous. A third approach, developed by Loral Data Systems in conjunction with Loral Instrumentation, is a 1553 Data Acquisition System that retains bus timing and protocol and synchronizes the signal to a common clock.
    • REMOTE AIRCRAFT MAINTENANCE MONITORING USING TELEMETRY

      Dowling, Drew; Lancaster, Richard A.; ARINC Research Corporation (International Foundation for Telemetering, 1985-10)
      The purpose of this paper is to present a concept utilizing digital telemetry links to upgrade the military aircraft maintenance approach in the future. The evolution of digital avionics in both military and commercial aircraft is creating changes that affect today’s approach to maintenance. Commercial aviation has made significant progress in the direction of maintenance monitoring using a digital telemetry link. This paper presents the status of maintenance-monitoring efforts within the commercial airlines and, recognizing the differences that exist between the military and commercial application, proposes an aircraft maintenance concept for the military in the 1990s.
    • PCM SIMULATOR ARCHITECTURE REDUCES SETUP COMPLEXITY

      Thom, Gary A.; General Data Products, Inc. (International Foundation for Telemetering, 1985-10)
      The advent of Bit Slice Processors and related architectures has produced numerous high performance PCM Data Simulators. Many of these fall into the category of stored program simulators, which give the user unlimited flexibility and power. These simulators allow the user to program almost any imaginable format, with combinations of subframes, subsubframes, and asynchronously embedded subframes. The drawback is that the user is forced to program the simulator using a very detailed machine level language which usually has no obvious relation to PCM frame formats. A new simulator architecture allows the user to describe the frame format to be simulated in familiar terms. This eliminates the need to learn yet another programming language or develop a Compiler. The user identifies common parameters such as frame length, subframe length, and where special words should be located. These special words can be unique sensor data words, a table of sensor data, ID counters, subframe slots and so on.
    • THE ADVANTAGES OF APPLYING GPS FREQUENCY TRANSLATORS TO RANGE TRACKING

      Hoefener, Carl E.; Stone, James; Interstate Electronics Corporation (International Foundation for Telemetering, 1985-10)
      When applying the Global Positioning System (GPS) to Time, Space, and Position Information (TSPI), the use of GPS frequency translators should be considered. The primary space positioning problem in the test and evaluation applications is trajectory reconstruction. Although this can be accomplished by flying a GPS receiver on the test vehicle and telemetering its position to the ground, there are significant advantages to translating the “L” band GPS signals to “S” band, and transmitting the broad band signal to the ground for processing. A translator-based system offers several advantages. Physical advantages include smaller size, lower weight, and lower cost. Technical advantages include: 1) ground station data aiding that provides a 6 dB advantage, 2) elimination of system bias errors, 3) computation complexity at the ground station vs. the vehicle under test, and 4) the ability to reconstruct a test scenario enabling flexibility in data analysis techniques.
    • CODE TRACKING ERROR IN THE PRESENCE OF INTERFERENCE SIGNAL

      Mohanty, Nirode C.; The Aerospace Corporation (International Foundation for Telemetering, 1985-10)
      The performance of a code tracking loop for a spread spectrum signal can be severely deteriorated in the presence of an interference signal. The interference signal is modeled as a signal with the same code but with a different delay and carrier frequency. The variance of the tracking delay error is derived in terms of loop bandwidth, chip duration, the interference and signal power and bandpass filter bandwidth and the power spectral density of the additive Gaussian noise.
    • Flight Test Instrumentation System FTIS for Type-Certification of the Indonesian Aircraft CN 235

      Klewe, Hans-Joachim; Soelaiman, Adi Dharma; DFVLR, Institute for Flight Mechanics, Braunschweig/Germany; PT. NURTANIO, Bandung/Indonesia (International Foundation for Telemetering, 1985-10)
      Certification of an Aircraft necessitates ample instrumentation equipment to get all the data needed. The Flight Test Instrumentation System for the Indonesian Aircraft CN 235 (Fig. 1) does not consist only of the necessary data acquisition and evaluation systems, but includes moreover all the subsystems which are needed in flight testing like airborne- and ground-calibration systems, video and camera-installations etc. The Mobile Ground Station is housed in 14 shelters including a power-station and can be seen as a selfsupporting system. Design and procurement by DFVLR assisted by Indonesian engineers as well as assistance through DFVLR in Indonesia was a first leading project in the course of the establishment of an Indonesian Flight Mechanics Laboratory FML. After service in Type Certification of the CN 235 the Flight Test Instrumentation System described will have a wide application range for future projects. To get a staff of engineers scilled in the art of flight-testing a training program for 10 Indonesian engineers was conducted by DFVLR, so that there are experts to operate the system in Indonesia. Since 1984 the Flight Test Instrumentation System is in use in Bandung or Jakarta resp.