• The Need for Standardized Performance Characteristics for Digital Strip Chart Recorders

      Smith, Grant M.; Gaskill, Dave; Astro-Med, Inc. (International Foundation for Telemetering, 1988-10)
      Digital-based linear-array chart recorders are replacing conventional stylus recorders in telemetry data stations everywhere. They offer advantages in virtually all respects, and are becoming indispensable. But because of the completely different writing method and technology employed, it is difficult to make completely analogous performance comparisons between analog and digital chart recorders. This has led to some confusion when replacing aging stylus recorders is contemplated. Objectives: Establish a set of universal, standardized performance characteristics for digital chart recorders. Introduce appropriate terminology, allowing valid, repeatable comparison of old and new systems.
    • Software Control of a High Speed, Modular Signal Conditioner and PCM Encoder System

      Trover, William F.; Teledyne Controls (International Foundation for Telemetering, 1988-10)
      The increasing channel capacity and complexity of flight test data acquisition systems have made the problems of physical distribution of the system throughout the test aircraft and determining the system configuration a very time consuming and costly portion of the flight test process. These problems are complicated because the new aircraft, irrespective of size, have more complex systems and less space is available to install the classical data acquisition and recording system. The solution to the installation problem is to have a highly modular system that can be configured as either a distributed system with remote multiplexing and a PCM Central Controller, or with the same multiplexed hardware as a stand-alone or master/slave system where the functional power and complexity afforded by the PCM Central Controller are not required. The solution to the configuration control problem is to have a 'hands-off' data acquisition system with all variables of the signal conditioning and PCM encoding functions under software control. In one concept, this includes functions such as instrumentation amplifier gains and offsets, presample filter knee selection, a common gain programmable amplifier with programmable offsets, and randomly addressable multiplexers with a PCM Central Controller that can store multiple data cycle maps. With all of the variable functions of the system under software control, system configuration can be determined automatically during pre- and post-flight test from a portable ground test set that produces a hardcopy printout of the system configuration. This system concept is being augmented by increasing sampling rate capability up to 500k sps for processing vibration/acoustic data. Fiber optical communications are available between the PCM Central Controller and the remote signal conditioners and multiplexers to provide immunity from extremely high common mode plateaus between subsystem elements located in different parts of a composite materials airframe. This next generation data system is being developed for general purpose flight and ground test applications.
    • MMTS: Multi-Vehicle Metric & Telemetry System

      Aspnes, Richard K.; Yuma, Russell J.; Control Data Corporation (International Foundation for Telemetering, 1988-10)
      The Multi-Vehicle Metric & Telemetry System (MMTS) is a complete range system which performs real-time tracking, command destruct, and telemetry processing functions for support of range safety and the test and evaluation of airborne vehicles. As currently configured, the MMTS consists of five hardware and software subsystems with the capability to receive, process, and display tracking data from up to ten range sensors and telemetry data from two instrumented vehicles. During a range operation, the MMTS is employed to collect, process, and display tracking and telemetry data. The instrumentation sites designated for operational support acquire tracking and telemetered data and transmit these data to the MMTS. The raw data is then identified, formatted, time tagged, recorded, processed, and routed for display to mission control and telemetry display areas. Additionally, processed tracking data is transmitted back to instrumentation sites as an aid to acquire or maintain vehicle track. The mission control area consists of a control and status console, high resolution color graphics stations, and large screen displays. As the mission controller observes mission progress on the graphics stations operational decisions can be made and invoked by activation of the appropriate console controls. Visual alarms provided my MMTS will alert mission control personnel of hazardous conditions posed by any tracked vehicle. Manual action can then be taken to activate transmission of the MMTS vehicle destruct signal. The telemetry display area consists of ten fully-functional, PC compatible computers which are switchable to either of two telemetry front end processors. Each PC can be independently set up by telemetry analysts to display data of interest. A total of thirty data pages per PC can be defined and any defined data page can be activated during a mission. A unique feature of the MMTS is that telemetry data can be combined with tracking data for use by the range safety functions.
    • A Flexible Telemetry Processor for Spacecraft Testing

      Leng, Christopher; Peet, Arthur; Jet Propulsion Laboratory/California Institute of Technology; Martin Marietta Astronautics Group (International Foundation for Telemetering, 1988-10)
      In the past, telemetry data systems in support of JPL flight projects -- such as Voyager and Galileo -- were designed specifically for each mission. Third-generation computers and minicomputers were combined into a distributed system, and many man-hours of software development were invested to meet each project's unique processing requirements. These systems were used to support the Spacecraft testing on the ground and -- later -- for mission operations after launch. The Magellan System Test Data Processing Subsystem (STDPS) marks a departure from these past designs. For the first time, a re-usable telemetry-processing subsystem has been designed that is flexible enough to meet the spacecraft-testing requirements of the present project -- and can be easily changed for future projects as well. These changes are all accomplished through a user-friendly, menu-oriented interface. Extensive software re-programming is no longer required. The Magellan spacecraft is being constructed for JPL by Martin Marietta Astronautics Group, Denver, Colorado. The STDPS is currently in Denver, supporting the spacecraft testing.
    • Characterization of Self-Focusing and Self-Defocusing of Light in Sodium Vapor

      Largent, C.; Northwestern University (International Foundation for Telemetering, 1988-10)
      Self-focusing of light in sodium vapor was first observed on a cw basis in 1974. Recently at Northwestern University, efforts to develop a quantum optical communications network employing squeezed states of light have required quantitative characterization of the self-action effects. It has been determined that self-focusing and self-defocusing change the spatial structure of the output beams of the forward four-wave mixer used in the experiments, thus worsening the homodyne-detection efficiency by creating a mismatch between the squeezed output beam and the local-oscillator beam. Consequently, the need to characterize the self-action effects in sodium vapor has arisen. By characterizing the self-action effects as a function of the sodium cell temperature, input beam intensity, and the dye laser frequency, it will be possible to modify the localoscillator wavefront to compensate for the spatial mismatch, and thus improve the homodyne-detection efficiency. This paper reports the results of an experiment carried out in the Fall and Winter Quarters of the 1987/1988 school year as an Honors Project in Electrical Engineering. The theories of self-focusing of optical beams and Gaussian beam propagation are developed early in the paper in order to lay the groundwork for the presentation and interpretation of the experimental results. A general description of the laboratory setup is given, and the experimental procedure is described in detail. Finally, the paper concludes with a presentation and interpretation of the experimental findings.
    • Generic Decommutation Capabilities in the Space Flight Operations Center

      O'Brien, Robin A.; Jet Propulsion Laboratory/California Institute of Technology (International Foundation for Telemetering, 1988-10)
      A generic decommutation capability has been created as part of the Space Flight Operation Center's goal of developing a multi-mission telemetry system. Generic decommutation involves separating the algorithmic description for extracting data from the actual implementation of decommutation. This was done by creating a Decommutation Map Language, which allows mission designers to describe decommutation algorithms without the restrictions imposed by a standard programming language. A Decommutation Map Compiler converts this description into C code, which is then linked with a decommutation library to provide an executable decommutation program. So far, this approach has been used successfully to decommutate several different types of data.
    • A New Multi-Mission Data System for Space Flight Support Through the 1990's

      Gainsborough, A. J.; California Institute of Technology (International Foundation for Telemetering, 1988-10)
      Individual data systems for flight projects at JPL are in the process of being replaced by the single new Space Flight Operations Center (SFOC) that is designed to support multiple missions. The design provides a baseline system that supplies a common set of functions needed by every mission. Low cost adaptations of the baseline with any needed missionspecific additions are made for each mission. The SFOC is being developed in phases. The current phase provides baseline functions for downlink spacecraft telemetry processing with the necessary adaptations and additions for the downlink launch support in April 1989 of the Magellan mission to Venus. The SFOC will be completed in 1991, at which time the planned support includes both downlink and uplink processing for a projected six mission set.
    • A New S-Band FM Telemetry Transmitter

      Fengden, Lou; Beijing Research Institute of Telemetry (International Foundation for Telemetering, 1988-10)
      This paper describes the design, test and the analysis of the test results of a new type S-band FM telemetry transmitter. Compared with the modulator adopting conventional fundamental crystal direct modulation, the transmitter which adopts UHF fundamental crystal direct modulation has a comparatively better modulation characteristics and a higher center frequency stability. The test results show that the deviation sensitivity of the transmitter is up to 400KHz/Vrms, frequency response is DC~200 KHz, total harmonic distortion is 3% and the center frequency stability is ten to the minus fifth power within the range of - 30~+70°c. Because of the high operating frequency of the modulator, the complicacy of the frequency multiplier has been requced, design of circuitry simplified and harmonic and spurious outputs has been improved to a great extent.
    • International Telemetering Conference Proceedings, Volume 24 (1988)

      International Foundation for Telemetering, 1988-10
    • Video Compression Techniques

      Cilke, Tom; LORAL/CONIC (International Foundation for Telemetering, 1988-10)
      This paper will attempt to present algorithms commonly used for video compression, and their effectiveness in aerospace applications where size, weight, and power are of prime importance. These techniques will include samples of one-, two-, and three-dimensional algorithms. Implementation of these algorithms into usable hardware is also explored but limited to monochrome video only.
    • Digital Microwave System Mobile, All-Terrain System for Telemetry or Communications

      Strom, Robert L.; Emmenegger, J. M. (Hans); Boeing Aerospace Company; Broadcast Microwave Services, Inc. (International Foundation for Telemetering, 1988-10)
      Portable, mobile tactical microwave telemetry and/or communications systems have always been plagued with three major problems: antenna height for first fresnel zone clearance over the terrain between the two ends of the link, atmospheric multipath fading and multipath reflections from buildings, bodies of water, certain terrain features, etc. This paper describes a digital microwave system with a modular capability to add additional digital channels, analog channels or voice channels as required. A modular Baseband Processor is used, which provides multiplexing capability and modulation of high speed digital data at a bandwidth of one bit per Hz using the Duobinary Technique which also provides error detection capability without the need for adding extra bits to the stream.
    • GPS: The Versatile Tool for Range Instrumentation

      Hoefener, Carl; Richardson, William; Interstate Electronics Corporation (International Foundation for Telemetering, 1988-10)
      The Global Positioning System (GPS) has made significant contributions in range instrumentation. It was the prime tracking method for both realtime range safety and metric tracking for the Trident II. Because of its many advantages, GPS will become the primary source of time, space, and position information (TSPI) on the ranges. Many activities requiring precision TSPI have already committed to GPS and others are planning on the application of GPS in the future for use on the ranges. GPS is also an extremely accurate time source, with timing accuracies of 10 nanoseconds obtainable worldwide. The range interoperability problem is solvable through the use of GPS as the TSPI source. There is little doubt that GPS will become the standard TSPI source for all test and training ranges.
    • Utilization of Real Time Digital Strip Chart Emulation (RTDSCE) Concepts

      Halsey, Tim; Brimbal, Michel; Grottenthaler, Gary; Gould Incorporated (International Foundation for Telemetering, 1988-10)
      "Real Time Digital Strip Chart Emulation", a paper presented in the 1987 ITC Proceedings is reviewed for continuity and the digital techniques applicable to range data display are expanded upon. The paper seeks to present the process of recording telemetered signals in the RTDSCE data management scheme. Direct hardware interfacing is discussed with emphasis on automation and manpower reduction. Time code display and various mass storage possibilities are explored. The merits of video monitoring and the workstation concept during playback are evaluated.
    • VLSI High Speed Packet Processor

      Grebowsky, Gerald J.; Dominy, Carol T.; NASA Goddard Space Flight Center (International Foundation for Telemetering, 1988-10)
      The Goddard Space Flight Center Mission Operations and Data Systems Directorate has developed a Packet Processor card utilizing semi-custom very large scale integration (VLSI) devices, microprocessors, and programmable gate arrays to support the implementation of multi-channel telemetry data capture systems. This card will receive synchronized error corrected telemetry transfer frames and output annotated application packets derived from this data. An adaptable format capability is provided by the programmability of three microprocessors while the throughput capability of the Packet Processor is achieved by a data pipeline consisting of two separate RAM systems controlled by specially designed semi-custom VLSI logic.
    • uDACS Micropackaged Data Acquisition and Control System

      Sodini, Gregory L.; SCI Technology Inc. (International Foundation for Telemetering, 1988-10)
      The miniaturization of Aerospace Systems, has created a demand for effective, compact, lightweight, and power efficient General Purpose Stand-Alone Flight Computers, as well as Command, Data Handling and Control Systems, that maintain High Reliability, Full Redundancy, Radiation Hardness, Explosive Processing Speed, Rapid Throughput, and High Accuracy. The innovative design techniques used in the uDACS (Micropackaged Data Acquisition and Control System) offer a unique and comprehensive solution to this quandary.
    • Addition of Video to Telemetry Tracking System Upgrades Spatial Data to Radar-Quality

      Fournier, John; Sullivan, Arthur; Electro Magnetic Processes, Inc. (International Foundation for Telemetering, 1988-10)
      Traditionally telemetry trackers have not been required to provide precision space-position data. Such data, when needed, has required expensive radar or optical support. Currently, an increasing number of flight test operations have need of precision spatial data, in conjunction with telemetry data reception, in areas where no radar or optical support is available. To meet this need, EMP has carefully combined existing technologies to upgrade the angle output data accuracy of telemetry trackers to the level expected of precision radars. A TV Boresight Camera and video Tracking Error Detector combined with the EMP Model ACU-6 microprocessor-based Antenna Control Unit provide the means to automatically measure and store all of the systematic bias errors inherent in a telemetry tracking system. The resulting error model is used to provide real-time-data-correction for each error parameter. Video tracking provides correction for dynamic tracking errors in real time. Calibrations utilize boresight and stellar targets. The design goal to reduce dynamic angle data error to <10 arc seconds, RMS, appears to be reasonable.
    • Spacecraft Telemetry Tracking State of the Art and Trends

      Mayer, Gerhard; DFVLR Applied Data Syst. Div. (International Foundation for Telemetering, 1988-10)
      Telemetry Tracking is a method of obtaining trajectory information regarding any flying body such as an aircraft, missile, satellite, balloon or a deep space probe which signals or "marks" its flight position by an electromagnetic radiating source. In a trade-off of costs it is an attractive way to combine Telemetry, Tracking and Command (TTC) facilities into one integrated system on board a spacecraft and with the ground receiving and tracking facilities. The present state of the art of Distance Measuring Equipment (DME) and Angle Measuring Equipment (AME) integrated with telemetry systems is reviewed. The further development will be mainly stimulated by the technology evolution of frequency and time reference sources, microwave components and information processing systems. An attempt is made to analyse which way the growth of technology will influence various system parameters.
    • A Charge-Balancing Incremental Analog to Digital Converter for Instrumental Applications

      Zrilić, D.; Skendzić, D.; Pajavić, S.; Ghorishi, R.; Fu, F.; Kandus, G.; Boston University (International Foundation for Telemetering, 1988-10)
      A switched-capacitor technique for realization of one bit serial A/D converter is presented. A conversion accuracy that is higher than 15 bits can be expected from its integrated realization. Results of simulation are presented. It is shown that arithmetic operations on bit serial signals are possible. Using arithmetic operations on delta-modulated signals, it is possible to build inexpensive options necessary in instrumentation.
    • A High Data Rate Airborne Rotary Recorder with Long Record Time

      Leung, Victor; DATATAPE Incorporated (International Foundation for Telemetering, 1988-10)
      Application of instrumentation recorders for data acquisition in hostile environments has for years been accomplished by means of longitudinal recorders specially designed for that application. DATATAPE Incorporated has been the leader in providing such recorders beginning with its MARS series. Two recent trends have impacted the applicability of these machines: the need for record times longer than can be provided by the longitudinal machines and the trend in the instrumentation industry to utilize digital recording techniques.
    • Analysis On the Optimum Group Synchronization Code of TIROS Satellite

      Qiu-Cheng, Xie; Jie, Cao; Nanjing Aeronautical Institute (International Foundation for Telemetering, 1988-10)
      In this paper, the group synchronization code (length n = 60 bit) of the TIROS Satellite was analysed. It seems to us the code isn't optimization. A series of optimum group sync codes (n = 60) have been searched out with error tolerance E = 1, 2, 3, 4, 5, 6 and 10, 12. Their error sync probabilities are less than the error sync probability of the TIROS code (from two times to two order of magnitudes about). These optimum or qansi-optimum codes will be presented for application in the second generation of the Meteorological Satellites of China.