• A GENERIC OBJECT-ORIENTED DESIGN FOR A RADIO FREQUENCY SIMULATION IN A SPACE TELEMETRY AND COMMAND ENVIRONMENT

      Policella, Joseph; CAE-Link Corporation (International Foundation for Telemetering, 1991-11)
      In a generic telemetry simulation the overall fidelity of the simulation is largely based on the simulated vehicle’s On-Board-Systems (OBS) engineering models that drive the generation of the telemetry. Also, the actual transfer of data between the simulated vehicle and control center depends on the ability of the Radio Frequency (RF) OBS to acquire and process the RF links thus resulting in a Acquisition of Signal or Loss of Signal (AOS/LOS) determination. The simulated RF links are a function of the communications OBS models, and the communications environment models. The communications OBS models are responsible for propagating the RF signal. Since the RF link analysis is highly integrated into the characteristics of the communications equipment and environment models, RF link software needs to be constantly redeveloped as communications equipment models change, fidelity is added, or multiple links are created. However, by using a generic objectoriented design, RF link software can process any number of differing links based on the RF characteristics of the propagated wave. As a result, the communications equipment model software can be changed to reflect possible design changes without having to rewrite the RF link software thus allowing reuse of existing code.
    • RECENT ADVANCES IN LOSSLESS CODING TECHNIQUES

      Yovanof, Gregory S.; Eastman Kodak Company (International Foundation for Telemetering, 1991-11)
      Lossless data compression systems allow an exact replica of the original data to be reproduced at the receiver. Lossless compression has found a wide range of applications in such diverse fields as: compression of computer data, still images (e.g., medical or graphical images) and video (usually, in the form of entropy coding of the output of intra/inter-frame lossy schemes). It has been studied for over forty years and new compression algorithms are still continuously developed. This paper is a survey of current lossless techniques with results quoted for both sequential data files and still images.
    • TELEMETRY IN TESTING OF UNDERSEAS WEAPONS

      Hull, Roy T., Jr.; Naval Undersea Warfare Engineering Station (International Foundation for Telemetering, 1991-11)
      The performance testing of underseas weapons involves many of the same challenges as for other “smart” systems. Data sets on the order of GigaBytes must be extracted, processed, analyzed, and stored. A few KiloBytes of significant information must be efficiently identified and accessed for analysis out of the great mass of data. Data from various sources must be time correlated and fused together to allow full analysis of the complex interactions which lead to a given test result. The fact that the various sources all use different formats and medias just adds to the fun. Testing of underseas weapons also involves some unique problems. Since real time data transmission is not practical; the vast bulk of the test data is recorded and then recovered with the vehicle at the end of the test. Acoustics are relied on for identification and ranging. As systems continue to get smarter; the rates, capacities, and “smarts” of the equipment and software used to process test data must similarly increase. The NUWES telemetry capabilities developed to test and analyze underseas weapons could be of use on other government related projects. “Key words: Telemetry, data processing, data analysis, undersea weapons, smart weapons, torpedoes, performance testing.”
    • REAL-TIME TELEMETRY DATA PROCESSING and LARGE SCALE PROCESSORS

      Dreibelbis, Harold N.; Kelsch, Dennis; James, Larry; H.D. Consultants, Ltd; CRAY Research, Inc.; LPJ Engineering (International Foundation for Telemetering, 1991-11)
      Real-time data processing of telemetry data has evolved from a highly centralized single large scale computer system to multiple mini-computers or super mini-computers tied together in a loosely coupled distributed network. Each mini-computer or super mini-computer essentially performing a single function in the real-time processing sequence of events. The reasons in the past for this evolution are many and varied. This paper will review some of the more significant factors in that evolution and will present some alternatives to a fully distributed mini-computer network that appear to offer significant real-time data processing advantages.
    • THE REAL/STAR 2000: A HIGH PERFORMANCE MULTIPROCESSOR COMPUTER FOR TELEMETRY APPLICATIONS

      Furht, B.; Gluch, D.; Parker, J.; Matthews, P.; Joseph, D.; Modular Computer Systems, Inc. (International Foundation for Telemetering, 1991-11)
      In this paper we describe the design of the REAL/STAR 2000 system, a highperformance real-time computer for telemetry applications. The REAL/STAR 2000 is a symmetric, tightly-coupled multiprocessor, optimized for real-time processing. The system provides a high level of scalability and flexibility by supporting three configurations: single, dual, and quad processor configurations, based on Motorola 88100 RISC processors. The system runs the multiprocessor REAL/IX operating system, a real-time implementation of the AT&T UNIX System V. It compiles with BCS and OCS standards, meets the POSIX 1003.1 standard, and has the current functionality of the emerging POSIX 1003.4 real-time standard. The REAL/STAR 2000 promotes an open system approach to real-time computing by supporting major industry standards. Benchmark results are also presented in the paper.
    • CARRIER PHASE MODULATION USING DIRECT DIGITAL SYNTHESIS FOR AN S-BAND UPLINK

      Burgess, George; Murphy, William; Stanford Telecommunications, Inc. (International Foundation for Telemetering, 1991-11)
      Phase modulation has traditionally been performed in analog hardware. A new product will be described that implements this function using a phase-modulating NCO IC. The modulating signal is sampled and added digitally to the phase of the carrier generated by the NCO. This method produces an output spectrum with highly accurate modulation control, low spur levels and minimal distortion. The effects of generating sampled phase-modulated signals will be described. The selection of the clock and output frequencies are critical to ensuring a clean spectrum. Resulting output spectra are shown.
    • A Real-time Counting-measuring Method for PPM(PPK) Signals

      Xi-Hua, Li; Xinan Electronic Engineering Institute, China (International Foundation for Telemetering, 1991-11)
      On the disscussion of custom real-time counting-measuring method, this paper presents a new method suitable for the working condition of non-man duty, which possesses the feature of 100ns counting-measuring accuracy and high fidelity. In addition, the concept of “Signal-time/digit converter” is proposed for the first time and the principle and working procedure of this method are introduced in brief.
    • ON IMPLEMENTATION OF REMOTELY OPERATED UNMANNED TELEMETRY TRACKING SYSTEMS WITH FIBER OPTIC CABLE

      TURNER, WILLIAM C.; ELECTRO-MAGNETIC PROCESSES, INC. (International Foundation for Telemetering, 1991-11)
      The high cost of real estate in countries with expanding populations, coupled with the long range capability of modern weapon systems has resulted in the need to expand test ranges to remote desert areas or areas over sea water. In order to preclude the cost of duplicating existing test centers, and the high cost of manually operating ground tracking stations, the requirement for unmanned remotely controlled telemetry tracking systems has emerged. Until recently, implementation of such systems has been trivial because the microwave link had sufficient bandwidth. However, with the advent of multi-TM bands, encrypted T.V. video and dual-polarization diversity requirements, implementation of unmanned remote stations has become cumbersome, expensive and less reliable. For instance, a pair of dedicated computers are now required to remotely control as many as eight receivers and four diversity combiners. This paper analyzes the advantages, limitations and feasibility of remotely controlling a wide-band antenna/pedestal with the restriction that all frequency downconverters, receivers, and combiners be located at the test center where they can be manually controlled and monitored, and more readily maintained. A comparison is made between the use of coaxial cable and fiber-optic cable as short-haul (0.25 to 25 kilometers) RF transmission media.
    • EVOLUTION OF THE DOD GLOBAL SPACE TEST CAPABILITY

      Grogan, James L., III; Fricks, Robert E. (International Foundation for Telemetering, 1991-11)
      This paper is an overview of progress toward a more formalized military space test range capability. It reviews the motivation for a space test function, relates history which has led to the contemporary space test operation, scopes existing space test pursuits and projects a direction for future activity. Its intent is to baseline the status of the current space test program and to present one vision for its future evolution.
    • INTERFRAME CODING OF VIDEO TELEMETRY SIGNALS

      Deutermann, Alan R.; Schaphorst, Richard A. (International Foundation for Telemetering, 1991-11)
      Television signals have been digitally transmitted for telemetry applications for several years. Reasons for digital transmission include the need for encryption, bandwidth compression, and the efficiency of time division multiplex. All digital coding techniques which have been employed to date, for video telemetry, are based on intraframe technology. In this case each TV frame is coded independently of the previous frames. In most video telemetry scenes there is a high degree of correlation between adjacent TV frames, and an interframe coding system which compresses the signal by reducing this frame-to-frame redundancy should be effective. This paper explores the potential advantages of interframe coding for video telemetry. Since this high level of compression typically causes the transmitted signal to be more sensitive to data link errors, the paper also examines advanced error control techniques.
    • RF SPECTRAL CHARACTERISTICS OF RANDOM PCM/FM AND PSK SIGNALS

      Law, E.L.; Pacific Missile Test Center (International Foundation for Telemetering, 1991-11)
      The telemetry radio frequency (RF) spectrum is rapidly becoming more crowded. Therefore, telemetry system engineers and frequency managers must become more knowledgeable about the RF spectral characteristics of telemetry signals. This paper presents methods to calculate the expected RF spectrum of random non-return-to-zero (NRZ) pulse code modulation (PCM)/frequency modulation (FM) and phase shift key (PSK) signals. The discussion includes the effects of bit rate, peak deviation, premodulation filtering, and spectrum analyzer resolution bandwidth. The methods are easily implemented using a personal computer and a spreadsheet program with graphics capability. Calculated spectra agree well with measured spectra. Equations are presented for accurately estimating the peak deviation and unmodulated carrier power of a random NRZ PCM/FM signal from the measured RF spectrum. Adjacent channel interference is also calculated. Key words: radio frequency spectral occupancy, pulse code modulation, frequency modulation, phase shift keying, premodulation filtering, adjacent channel interference.
    • RAPID PROTOTYPING AS AN ACQUISITION STRATEGY OF THE AIR FORCE SATELLITE CONTROL NETWORK

      Whipple, L.K.; Hoida, T.J.; USAF Space Systems Division (International Foundation for Telemetering, 1991-11)
      The Air Force Satellite Control Network (AFSCN) processes on the order of a thousand separate requirements each year to enhance Network capability to meet the support needs of various satellites. Many of these individual requirements are translated into modifications or additions to the network assets. Rapid Prototyping has been utilized successfully for complex and urgent developments to meet many of these requirements. Rapid Prototyping has also been used for requirements definition and for defining man/machine interfaces. Through Rapid Prototyping, the AFSCN has successfully developed applications using new technology and has improved the process of defining requirements for operational satellite support systems. Rapid prototyping is proving to be an effective alternative to the traditional system acquisition process
    • THE EVOLUTION OF AFSCN TELEMETRY SIMULATION SYSTEMS

      Dessling, R.W.; Lockheed Technical Operations Company (International Foundation for Telemetering, 1991-11)
      The Air Force satellite control capability was started in the late 1950s to support command and control of orbiting spacecraft. A need to train and certify ground support personnel as well as to validate equipment configurations soon became evident. Ground personnel would have to know how to generate satellite contact plans, establish connectivity between the satellite and telemetry display terminals, analyze satellite telemetry data, and transmit commands to execute the contact plans. They would have to learn specific ground systems capabilities, satellite design information, and approved command and control procedures. This presentation will review the evolution of telemetry simulation systems as they apply to systems test, personnel training and evaluation. Included will be a discussion of the ground and satellite systems, and how system upgrades and changing operations concepts have fostered the development of telemetry simulators. In describing the next generation of AFSCN simulation systems, this paper will highlight the important part they play in validating system configuration and in personnel training.
    • A SIMPLE DECOMMUTATION SCHEME FOR THE TELEMETRY TEST STATION

      Martin, Kamalini; Vanitha, M.; Manjunath, P.C. (International Foundation for Telemetering, 1991-11)
      The Telemetry Test Station has been developed at the Digital Systems Division, ISRO Satellite Centre, to test the housekeeping telemetry packages which will be flown onboard satellites. The heart of the test procedure is the decommutation, display and processing of the telemetry output format. The decommutation has been achieved by designing a simple plug in card to an IBM PC/XT compatible computer and writing the related assembly language software. The card and the software have been extensively tested and found to work satisfactorily upto 60 Kbps PCM data rate. To make the hardware and software flexible and truly general purpose, the acquisition should be independent of the modes of operation and data formats. All the parameters which define acquisition display and processing are therefore programmable and can be changed at any time. The parameters which influence acquisition are bit rate, word rate, frame rate, length of word, length of frame and frame synchronous code. The bit rate is transparent, i.e., need not be set by the user. The word length is assumed to be 8 bits or multiples of 8 bits. The other parameters are programmable at any time during the test session. Similarly, the parameters which affect display are the display rate, and positioning of the format including highlighting, alarm signals, related information etc. This gives a user the facility to tailor the display to his liking. The storage is also flexible and independent of display. All these modes are in real time and have therefore been coded in assembly. It has been found that a large part of the software is needed for user interface alone and user requirement is far more changeable than expected. The software is therefore designed for change. The problems and solutions in achieving these features are discussed in this paper.
    • MODERNIZING THE REMOTE TRACKING STATION

      Blanchard, W. N. (International Foundation for Telemetering, 1991-11)
      Since the inception of the Air Force Satellite Control Network (AFSCN) in the late 1950s, capabilities of the network’s Remote Tracking Stations (RTSs) were evolutionarily developed to meet satellite Tracking, Telemetry, and Commanding (TT&C) needs. The result, although fully satisfactory operationally, was an RTS network requiring manpowerintensive mission support. Additionally, reconfiguration of an RTS between satellite contacts consumed far more time than was operationally desirable as demands for RTS contact support continued to grow. To improve network responsiveness and cost effectiveness, the Air Force undertook, in the mid-1980s, a major “block upgrade” under the Automated Remote Tracking Station (ARTS) Program. This paper traces historical RTS capabilities, identifies emerging mid1980s RTS support requirements, and defines the operational and financial advantages accruing to the Air Force through ARTS implementation to meet those requirements. Possible future upgrades to further enhance AFSCN TT&C mission capability are also briefly discussed.
    • A SIMULATOR OF PCM STREAM WITH HIGH DATA RATE

      Liang, LI Xian; QiShan, Zhang; Hui, Yang; BEIJING UNIVERSITY OF AERONAUTICS AND ASTRONAUTICS (International Foundation for Telemetering, 1991-11)
      The simulator of PCM data stream is an important apparatus. Without an advanced high data rate simulator, were not there a PCM system with advanced performance. After careful study, a simulator in laboratory of PCM stream with the data rate up to 30 Mbps is now designed. Our simulator differs from the traditional ones in the design principle and can bring all potentialities into play. It is more powerful in function, easier to test and more accurate in control. In the meanwhile, it can keep compatible with old simulators.
    • AN AUTOMATED TESTING SYSTEM FOR A TELEMETRY TRACKING SYSTEM

      MARSH, TED A.; INSTRUMENTATION DIRECTORATE (International Foundation for Telemetering, 1991-11)
      White Sands Missile Range (WSMR) has developed an Advanced Transportable Telemetry Acquisition System (TTAS-A) which utilizes a dedicated computer system for antenna control. The Automated Testing System (ATS), an integral part of this system, is the subject of this paper. The ATS consists of hardware and software designed to provide fully automated testing of the radio frequency (RF) and servo subsystems for validation purposes. The RF subsystem tests are designed to evaluate, measure, and display RF performance parameters such as receiving system Figure of Merit and RF system sensitivity. The servo subsystem tests are designed to evaluate and display the stability and response characteristics of the servo subsystem. Tests are accessed via a keyboard, and extensive use of menus makes the software easy to learn and use. The test equipment is controlled entirely by the computer, and hard copies of all test results are available on the system printer.
    • A PRECISION TRANSPORTABLE TRACKING TELEMETRY SYSTEM

      Morris, R.A.; Powell, W.R.; Bundick, S.N.; Scientific-Atlanta, Inc.; NASA/Goddard Space Flight Center (International Foundation for Telemetering, 1991-11)
      Changing mission requirements have forced NASA to procure a new generation of tracking telemetry system with performance and features greatly exceeding existing system capabilities in many areas. These requirements and the system that was designed to meet them are discussed. Initial results of system testing are presented.
    • A PC-Based Telemetry System for Acquiring and Reducing Data from Multiple PCM Streams

      Simms, D. A.; Butterfield, C. P.; Solar Energy Research Institute (International Foundation for Telemetering, 1991-11)
      The Solar Energy Research Institute’s (SERI) Wind Research Program is using Pulse Code Modulation (PCM) telemetry data-acquisition systems to study horizontal-axis wind turbines. Many PCM systems are combined for use in test installations that require accurate measurements from a variety of different locations. SERI has found them ideal for data-acquisition from multiple wind turbines and meteorological towers in wind parks. A major problem has been in providing the capability to quickly combine and examine incoming data from multiple PCM sources in the field. To solve this problem, SERI has developed a low-cost PC-based PCM telemetry data-reduction system to facilitate quick, in-the-field multiple-channel data analysis. Called the “PC-PCM System,” it consists of two basic components. First, PC-compatible hardware boards are used to decode and combine multiple PCM data streams. Up to four hardware boards can be installed in a single PC, which provides the capability to combine data from four PCM streams directly to PC disk or memory. Each stream can have up to 62 data channels. Second, a software package written for use under DOS was developed to simplify data-acquisition control and management. The software provides a quick, easy-to-use interface between the PC and multiple PCM data streams. Called the “Quick-Look Data Management Program,” it is a comprehensive menu-driven package used to organize, acquire, process, and display information from incoming PCM data streams. This paper describes both hardware and software aspects of the SERI PC-PCM system, concentrating on features that make it useful in an experiment test environment to quickly examine and verify incoming data from multiple PCM streams. Also discussed are problems and techniques associated with PC-based telemetry data-acquisition, processing, and real-time display.
    • HIGH SPEED FIBER OPTIC TELEMETRY SYSTEM FOR AN UNMANNED, TETHERED, UNDERWATER VEHICLE

      Hui, C.K.; Morinaga, W.S.; Naval Ocean Systems Center, Hawaii Laboratory (International Foundation for Telemetering, 1991-11)
      The Naval Ocean Systems Center (NOSC) has developed the Advanced Tethered Vehicle (ATV) that can perform a variety of tasks at ocean depths to 20,000 feet. The ATV employs a bidirectional, fiber optic telemetry system. The design of the telemetry was validated by at-sea testing and its reliability contributed to the ATV’s successful deep ocean operations. The telemetry system transmits commands to the vehicle, and two videos and sensor data to the surface over a single optical fiber. Design requirements, descriptions, and implementation of a high speed 200 Megabits-per-second (Mbps) uplink and a 5 Mbps downlink Time Division Multiplexed telemetry system are discussed in this paper.