Kayes, Edwin (International Foundation for Telemetering, 1995-11)
      Magnetic tape is the primary medium used to capture and store unprocessed data from remote sensing satellites. Recent advances in digital cassette recording technology have resulted in the introduction of a range of data recorders which are equally at home working alongside conventional recorders or as part of more advanced data capture strategies. This paper shows how users are taking advantage of the convenience, economy and efficiency of this new generation of cassette-based equipment in a range of practical applications.

      Buschbach, Charles W.; Metrum (International Foundation for Telemetering, 1995-11)
      Half inch Super VHS (S-VHS) tape is an exceptional media for recording telemetry instrumentation data. Due to high volume mass production for the commercial and industrial video markets, high quality S-VHS media is available at a low cost. Advances in head technology as well as data path electronics contribute to increased data densities recorded on this media. Present system capabilities of 50,000 bits per inch will soon be replaced with newer technology systems that will record at linear densities up to 100,000 bits per inch.

      Cirineo, Tony; Troublefield, Bob; NAWCWPNS (International Foundation for Telemetering, 1995-11)
      This paper describes an Engineering Development Model (EDM) for the Standard Interoperable Datalink System (SIDS). This EDM represents an attempt to design and build a programmable system that can be used to test and evaluate various aspects of a modern digital datalink. First, an investigation was started of commercial wireless components and standards that could be used to construct the SIDS datalink. This investigation lead to the construction of an engineering developmental model. This model presently consists of wire wrap and prototype circuits that implement many aspects of a modern digital datalink.
    • Optimizing Bandwidth Utilization in Packet Based Telemetry Systems

      Kalibjian, Jeffrey R.; Lawrence Livermore National Laboratory (International Foundation for Telemetering, 1995-11)
      A consistent theme in spacecraft telemetry system design is the desire to obtain maximum bandwidth utilization given a fixed transmission capability (usually due to cost/weight criteria). Extensions to basic packetization telemetry architectures are discussed which can facilitate a reduction in the amount of actual data telemetered, without loss of data quality. Central to the extensions are the establishment of an "intelligent" telemetry process, which can evaluate pending data to be telemetered, and act to compress, discard, or re-formulate data before actual transmission to ground stations.

      Cullen J. M.; Keller, Ed; Eglin Air Force Base (International Foundation for Telemetering, 1995-11)
      The Instrumentation Technology Branch of Wright Laboratory Armament Directorate (WL/MNSI), has successfully completed an Exploratory Development (6.2) program to develop Subminiature Telemetry (SMT). SMT is a flexible, programmable telemeter with self calibration, power control and Direct Sequence Spread Spectrum modulation. The development program successfully demonstrated the ability of the SMT system to collect up to 64 analog and/or 128 digital discrete signals with programmable gain, bandwidth and offset. The program demonstrated a spread spectrum multiple-access technique that allows for simultaneous transmission and receipt of up to 96 different telemetry units within a 100 MHz telemetry band. WL/MNSI is conducting an Advanced Technology Development (6.3) program to continue development in this area. An air-worthy 4 channel spread spectrum demodulator was developed to support the SMT program but it is too costly for ground applications. The goals of this effort are to reduce the demodulator cost by a factor of 10 while increasing the capability for simultaneously processing data from 24 telemetry units and to support the first Technology Transition Plan (TTP) between WL/MN and the Air Force Development Test Center (AFDTC). The TTP will facilitate the transition of SMT spread spectrum technology to AFDTC for mission support over the next three years.

      Law, Eugene L.; NAWCWPNS (International Foundation for Telemetering, 1995-11)
      This paper will present and compare several definitions of telemetry radio frequency (RF) signal bandwidth. Measured spectra for different signals will be presented. The bandwidths of these signals will then be determined and measurement methods will be discussed. This discussion will include the effects of spectrum analyzer resolution bandwidth, video bandwidth and detector type. Finally, a proposed spectral mask will be discussed. This spectral mask can be used to calculate the required attenuation for a given frequency offset from the center frequency. The required attenuation is a function of the the bit rate or maximum frequency of interest and the transmitter power. This spectral mask is proposed to be part of the next edition of the Telemetry Standards, Inter-Range Instrumentation Group (IRIG) Standard 106.

      Thursby, William R. Jr; Shirley, Benjamin M.; Eglin Air Force Base (International Foundation for Telemetering, 1995-11)
      Eglin Air Force Base (AFB) plans to demonstrate subminiature telemetry (SMT) spread spectrum technology, via an upgraded prototype SMT system, to validate its cost-effectiveness for both Department of Defense (DoD) and commercial use. The goal is to develop new and/or modify current SMT instrumentation using existing production methods to provide increased capabilities at lower costs and reduced size. The transmitter is to require less than 2 cubic inches of space and have a cost goal of $500/unit "in quantity." The cost goal of a ground-based, 24-channel capable ground receiver is $4000/unit "in quantity". The SMT project as well as its schedule, flight and ground demonstrations, validation criteria and goals, and various benefits are discussed.

      Augustin, E. P.; Dunn, D. S.; Posada, J. F.; Sullivan, A.; Technical Systems Associates, Inc. (International Foundation for Telemetering, 1995-11)
      This paper describes a novel Radiating Antenna Digital Pattern Analysis Test system (RADPAT). The RADPAT system consists of a portable computer and a compact electronic module (EM) that interfaces to the antenna under test . The EM has standardized inputs and outputs that make it easy to adapt to any antenna or antenna system. In addition to functioning as a standard radiation pattern recorder, the RADPAT system can record conically scanning (CONSCAN), single channel monopulse, or sequential lobing patterns with only one sweep per axis . Since the radiation pattern is recorded digitally, it can automatically extract actual system data such as the error slope, crosstalk, 3 or 10 dB beamwidths, sidelobe levels, boresight shift, etc.. The briefcase size RADPAT system is portable, weighing only 18 lbs (8 kg). This can be a significant advantage for either verification of system parameters or for troubleshooting a component or system problem . Thus, the RADPAT system combined with a standard pattern receiver or a telemetry receiver can provide instantaneous, on-site evaluation of the radiation characteristics of an installed antenna system.
    • Object-Oriented Design of a Windows™ Based Automated Telemetry System

      Self, Lance P. L.; NAWC-Weapons Division (International Foundation for Telemetering, 1995-11)
      This paper illustrates a Windows computer application program which uses the object-oriented paradigm as a basis. The objective of the application program is to control the setup of equipment involved in routing a telemetry signal. This design uses abstract classes as high level building blocks from which site specific classes are derived. It is the next generation to the software portion of a system described by Eugene L. Law. The object-oriented design method, as presented by Grady Booch in his book Object-Oriented Analysis and Design with Applications, is the design tool.

      Stone, Christopher E.; Flint, Keith D.; Mathis, Gregory P.; Edwards Air Force Base (International Foundation for Telemetering, 1995-11)
      Phillips Laboratory's Space Experiments Directorate (PL/SX) is operating and upgrading the laboratory's premier transportable satellite tracking station, the Mobile Ground Tracking Station (MGTS) program. MGTS supports orbital, suborbital, and aircraft missions as a range system capable of processing and recording multiple data streams. MGTS receives, processes, displays, and records satellite state-of-health data, infrared images in a variety of wavelengths, video data, and state vector solutions based on IR returns from the Miniature Sensor Technology Integration (MSTI) satellite program. The program has began in 1990 under BMDO sponsorship, with the intent to supplement existing test ranges with more flexibility in range operations. Wyle Laboratories and Systems Engineering and Management Company (SEMCO) provided the technical expertise necessary to create the first MGTS system. Autonomy and off-road capability were critical design factors, since some of the operations envisioned require deployment to remote or hostile field locations. Since inception, MGTS has supported the Lightweight Exo-Atmospheric Projectile (LEAP) sub-orbital missions, the MSTI satellite program, and Air Force wargame demonstrations. In pursuit of these missions, MGTS has deployed to White Sands Missile Range (WSMR), NM; Air Force Flight Test Center (AFFTC), Edwards AFB, CA; Vandenberg AFB, CA; Falcon AFB, CO; and NASA's Wallops Island Flight Facility, VA, to receive critical mission telemetry data conforming to both IRIG and SGLS standards. This paper will describe the evolution of the MGTS program, current hardware configurations and past and future mission scenarios for the MGTS team.

      Kronberg, F.; Ringrose, P.; Losik, L.; Biroscak, D.; Malina, R. F. (International Foundation for Telemetering, 1995-11)
      The UC Berkeley Extreme Ultraviolet Explorer (EUVE) Science Operations Center (ESOC) is developing and implementing knowledge-based software to automate the monitoring of satellite payload telemetry. Formerly, EUVE science payload data were received, archived, interpreted, and responded to during round-the-clock monitoring by human operators. Now, knowledge-based software will support, augment, and supplement human intervention. In response to and as a result of this re-engineering project, the creation, storage, revision, and communication of information (the information flow process) within the ESOC has been redesigned. We review the information flow process within the ESOC before, during, and after the re-engineering of telemetry monitoring. We identify six fundamental challenges we face in modifying the information flow process. (These modifications are necessary because of the shift from continuous human monitoring to a knowledge-based autonomous monitoring system with intermittent human response.) We describe the innovations we have implemented in the ESOC information systems, including innovations in each part of the information flow process for short-term or dynamic information (which changes or updates within a week) as well as for long-term or static information (which is valid for more than a week). We discuss our phased approach to these innovations, in which modifications were made in small increments and the lessons learned at each step were incorporated into subsequent modifications. We analyze some mistakes and present lessons learned from our experience.
    • Developing Communication and Data Systems for Space Station Facility Class Payloads

      Hazra, Tushar K.; Sun, Charles; Mian, Arshad M.; Picinich, Louis M.; NASA (International Foundation for Telemetering, 1995-11)
      The driving force in modern space mission control has been directed towards developing cost effective and reliable communication and data systems. The objective is to maintain and ensure error-free payload commanding and data acquisition as well as efficient processing of the payload data for concurrent, real time and future use. While Mainframe computing still comprises a majority of commercially available communication and data systems, a significant diversion can be noticed towards utilizing a distributed network of workstations and commercially available software and hardware. This motivation reflects advances in modem computer technology and the trend in space mission control today and in the future. The development of communication and data involves the implementation of distributed and parallel processing concepts in a network of highly powerful client server environments. This paper addresses major issues related to developing and integrating communication and data system and the significance for future developments.

      Davis, Don; Bennett, Toby; Harris, Jonathan; NASA; RMS Technologies (International Foundation for Telemetering, 1995-11)
      The wide use of standard packet telemetry protocols based on the Consultative Committee for Space Data Systems (CCSDS) recommendations in future space science missions has created a large demand for low-cost ground CCSDS processing systems. Some of the National Aeronautics and Space Administration (NASA) missions using CCSDS telemetry include Small Explorer, Earth Observing System (EOS), Space Station, and Advanced Composite Explorer. For each mission, ground telemetry systems are typically used in a variety of applications including spacecraft development facilities, mission control centers, science data processing sites, tracking stations, launch support equipment, and compatibility test systems. The future deployment of EOS spacecraft allowing direct broadcast of data to science users will further increase demand for such systems. For the last ten years, the Data Systems Technology Division (DSTD) at NASA Goddard Space Flight Center (GSFC) has been applying state-of-the-art commercial Very Large Scale Integration (VLSI) Application Specific Integrated Circuit (ASIC) technology to further reduce the cost of ground telemetry data systems. As a continuation of this effort, a new desktop CCSDS processing system is being prototyped that offers up to 150 Mbps performance at a replication cost of less than $20K. This system acts as a gateway that captures and processes CCSDS telemetry streams and delivers them to users over standard commercial network interfaces. This paper describes the development of this prototype system based on the Peripheral Component Interconnect (PCI) bus and 0.6 micron complementary metal oxide semiconductor (CMOS) ASIC technology. The system performs frame synchronization, bit transition density decoding, cyclic redundancy code (CRC) error checking, Reed-Solomon decoding, virtual channel sorting/filtering, packet extraction, and quality annotation and accounting at data rates up to and beyond 150 Mbps.
    • Multi-functions Integration and Intermodulation Interference of TT&C system

      Jiaxing, Liu; The Southwest Insititute of Electronics Technology (International Foundation for Telemetering, 1995-11)
      This paper describes technical problems in system integration, Intermodulatin interference, digitalization, obital accuracy, low-noise design of the new generation TT&C system as well as their solutions.

      Richard, Gaetan C.; Gonzales, Daniel G.; Malibu Research, Inc. (International Foundation for Telemetering, 1995-11)
      The use of low windload FLAPS™ antennas in telemetry tracking systems yields sizable savings in system cost due to the reduced requirements imposed on the pedestal assembly and on the underlying support structure. Traditionally the use of these antennas has been limited to applications in which frequency bandwidths did not exceed 10-13%. This paper describes a variation of the FLAPS™ technology which allows operation over bandwidths in excess of 35% and makes it usable in broadband systems. Two new applications are feasible: one for a ground based telemetry system operating in the 1435-1850 or 1750-2400 MHz band and one for a shipboard satellite communication system operating in the 4000-6000 MHz band.

      Dye, Ricky G.; Horne, Lyman D.; Brigham Young University (International Foundation for Telemetering, 1995-11)
      The aeronautical channel model is a good candidate for modeling the effects of multipath interference of telemetry signals on test ranges. The aeronautical fading channel model is parameterized by the signal to noise ratio, the Doppler shift and time delay between the specular and direct components, the specular to direct power ratio, the direct to diffuse power ratio, and the bandwidth of the multipath fading process. Segments of weighting signal data measured during a test at Tyndall AFB provide data which can be used to determine typical values of the above parameters in a variety of telemetering environments. In this paper, the set of parameters which most closely model the actual telemetry channel using the Tyndall data is determined.

      Jones, Charles H.; Edwards Air Force Base (International Foundation for Telemetering, 1995-11)
      In its simplest form an automaton can be considered a set of inputs, a process, and a set of outputs. Certainly telemetry can be thought of in this way as well. Automata theory is a cross between mathematics and computer science which considers how to precisely define the inputs, the outputs, and the process of translating the one into the other. The input to an automaton can be described using a formal grammar. Two standard bit stream encodings, PCM matrices and MIL-STD-1553, are described using grammars. An example of how a grammar can be used to decode a bit stream is given. Further, ambiguity and complexity of bit stream encodings are discussed in the context of grammars. It is thus illustrated how grammars can be used to cleanly define and decode telemetry bit streams.

      Horne, Lyman D.; Dye, Ricky G.; Brigham Young University (International Foundation for Telemetering, 1995-11)
      In an effort to determine a more accurate characterization of the multipath fading effects on telemetry signals, the BYU telemetering group is implementing an inexpensive data acquisition system to measure these effects. It is designed to measure important signals in a diversity combining system. The received RF envelope, AGC signal, and the weighting signal for each beam, as well as the IRIG B time stamp will be sampled and stored. This system is based on an 80x86 platform for simplicity, compactness, and ease of use. The design is robust and portable to accommodate measurements in a variety of locations including aircraft, ground, and mobile environments.

      Reed, Ryan; Long, David G.; Arnold, David V. (International Foundation for Telemetering, 1995-11)
      A scatterometer is a radar system designed to make precise measurements of the magnitude of the radar echo scattered from surface. If the measurement is made over the ocean's surface, the surface wind speed and direction can be inferred. In order to better understand the relationship between the radar return and the ocean winds we have developed a unique ultra-wide band research scatterometer known as Yscat. The Yscat radar system is computer controlled, with a separate computer collecting environmental data. During a typical deployment, such as a recently completed 7 month deployment on Lake Ontario, the radar system is required to operate unmanned for weeks at a time, collecting data at a rate of up to 2 GB per week. Controlling such a complex system, and handling such large amounts of data presents a challenging remote operation problem. We used a novel combination of personal computers, telephone controlled switches, modems, and off the shelf software packages to enable us to perform daily monitoring, trouble shooting, and data transfer via a simple telephone connection. Data was stored on 4 mm DAT tapes for weekly pickup by a technician. This paper describes the Yscat system and our approach to control, monitoring, and data storage. While our approach is relatively "low tech", it has been very cost effective. This type of approach may be of interest to other designers of unique instrumentation at remote sites.

      Law, Eugene L.; NAWCWPNS (International Foundation for Telemetering, 1995-11)
      This paper will discuss the performance of pulse code modulation (PCM)/frequency modulation (FM) during frequency selective fading. Frequency selective fading occurs when the attenuation in part of the frequency band of interest is much greater than in the rest of the band of interest. The frequency selective fading model used in this paper assumes that two paths with different delays exist between the transmitter and receiver (multipath). The two-path model was simulated in the laboratory and the effects of frequency selective fading on the radio frequency (RF) spectrum and on the waveforms at the output of the FM demodulator were measured. A mathematical model was also used to predict the effects of frequency selective fading. The predicted waveshapes are compared with the laboratory data. A simple demodulator which alleviates the effects of frequency selective fading on PCM/FM at moderate signal-to-noise ratios (SNRs) will be described. This demodulator is created by detuning the telemetry receiver by a frequency equal to approximately one-half of the intermediate frequency (IF) bandwidth and using the receiver’s amplitude modulation (AM) detector output rather than the FM detector output. The performance of this offset AM demodulator will be compared with the performance of an FM demodulator. Frequency selective fades measured in real-world environments will be also presented.