• An IF Sampling Digital Receiver Implementation for Space-based Command and Telemetry Applications

      Maples, Bruce W.; Fix, Keith A.; CMC Electronics Cincinnati (International Foundation for Telemetering, 2002-10)
      This paper describes an approach to the implementation of an IF sampling digital receiver for low data rate command and telemetry applications in the NASA Goddard Spaceflight Tracking and Data Network (STDN) and Air Force Space-Ground Link System (SGLS). The digital design is targeted for an FPGA-based implementation and was written entirely in VHDL. Several size and clock reduction techniques are described which were utilized due to limited gate-array resources and power. The system-level design architecture is described followed by a discussion of algorithms and performance of critical stages in the receiver chain. Bit error performance of the prototype receiver is also presented. Finally, although this design is specifically targeted for a narrowband command and telemetry application, the methodology forms the basis of a configurable receiver for higher data rate applications.

      Eccles, Lee H.; Boeing Commercial Airplanes (International Foundation for Telemetering, 2002-10)
      Transducers have traditionally been incorporated into data systems by connecting the transducer to a signal conditioner that is then connected to a multiplexer with an Analog-to-Digital Converter (ADC). The signal conditioning, multiplexer and the ADC are usually included within the same assembly that is called a Data Acquisition Unit (DAU) or an encoder. A network centric data system allows the same architecture to be used if the interface to the encoder is changed to be a network interface. However, a network centric architecture allows other options as well. The signal conditioning and ADC can be included within the same package as the transducer and the assembly can be interfaced to the network. When this is combined with the processing capability now available, a whole new range of possibilities present themselves. The transducer can now be digitally processed to provide a linear output, it can be converted to Engineering Units, digitally filtered or have a host of other functions performed within the housing that contains the transducer. However, the network centric approach does not produce these advantages without some disadvantages. The major problem that needs to be solved is how we time stamp the data. With the encoder we could time stamp the PCM frame and be able to determine the time that a sample was taken from that information. Even in systems that convert the encoder to have a network interface, the time stamp needs to be affixed to the data in the encoder. With a network centric approach, the sample can be taken in the transducer and how to time stamp it becomes a real problem. This is a problem that must be considered at the system level. Some method of making time available at a low enough level in the system to allow transducer outputs to be time stamped is either a network issue or it requires a separate interface.

      Brierley, Scott; Boeing Company (International Foundation for Telemetering, 2002-10)
      Using a network-based telemetry system places additional requirements on the Radio Frequency (RF) link. Limitations imposed by this link must be considered in advance when designing a network-based telemetry system.
    • The Impact Of Wireless Security Protocols on Post Processed Telemetry Data Transfer

      Kalibjian, Jeffrey R.; Hewlett Packard Corporation (International Foundation for Telemetering, 2002-10)
      Commercial wireless protocol use (e.g. Wireless Access Protocol, Bluetooth, etc.) is becoming widespread as the demand to access computing devices in remote locations grows. Although not widely prevalent today, wireless access of post processed telemetry data will become a common activity. Essential to the use of such a capability is the security of the wireless links involved in the data transfer. Each wireless protocol has an associated security paradigm. Some protocols have stronger security schemes than others and this should influence protocol selection for particular telemetry data transfer applications.

      Hill, Terrance; Geoghegan, Mark; Hutzel, Kevin; Nova Engineering Inc. (International Foundation for Telemetering, 2002-10)
      Legacy telemetry systems, although widely deployed, are being severely taxed to support the high data rate requirements of advanced aircraft and missile platforms. Increasing data rates, in conjunction with loss of spectrum have created a need to use available spectrum more efficiently. In response to this, new modulation techniques have been developed which offer more data capacity in the same operating bandwidth. Demodulation of these new waveforms is a computationally challenging task, especially at high data rates. This paper describes the design, implementation and performance of a high-speed, multi-mode demodulator for the Advanced Range Telemetry (ARTM) program which meets these challenges.

      Jefferis, Robert; TYBRIN Corporation (International Foundation for Telemetering, 2002-10)
      Multipath (MP) fading is the dominant channel impairment in many aeronautical telemetry links. One product of a recent multipath mitigation study is the discovery of a simple technique for detecting its presence over a useful range of conditions. The technique also detects significant random noise levels in the channel. This paper describes the “Signal Degradation Indicator” (SDI) and its application to FQPSK-B and SOQPSK [2] modulation. Laboratory emulation data is presented and implementation considerations are discussed.
    • International Telemetering Conference Proceedings, Volume 38 (2002)

      International Foundation for Telemetering, 2002-10

      Rash, James; Hogie, Keith; Casasanta, Ralph; NASA; Computer Sciences Corporation (International Foundation for Telemetering, 2002-10)
      Ongoing work at National Aeronautics and Space Administration Goddard Space Flight Center (NASA/GSFC), seeks to apply standard Internet applications and protocols to meet the technology challenge of future satellite missions. Internet protocols and technologies are under study as a future means to provide seamless dynamic communication among heterogeneous instruments, spacecraft, ground stations, constellations of spacecraft, and science investigators. The primary objective is to design and demonstrate in the laboratory the automated end-to-end transport of files in a simulated dynamic space environment using off-the-shelf, low-cost, commodity-level standard applications and protocols. The demonstrated functions and capabilities will become increasingly significant in the years to come as both earth and space science missions fly more sensors and the present labor-intensive, mission-specific techniques for processing and routing data become prohibitively. This paper describes how an IP-based communication architecture can support all existing operations concepts and how it will enable some new and complex communication and science concepts. The authors identify specific end-to-end data flows from the instruments to the control centers and scientists, and then describe how each data flow can be supported using standard Internet protocols and applications. The scenarios include normal data downlink and command uplink as well as recovery scenarios for both onboard and ground failures. The scenarios are based on an Earth orbiting spacecraft with downlink data rates from 300 Kbps to 4 Mbps. Included examples are based on designs currently being investigated for potential use by the Global Precipitation Measurement (GPM) mission.

      K/Bidy, Gilles; L-3 Communications (International Foundation for Telemetering, 2002-10)
      Because of an ever-increasing need for performance and high predictability in modern real-time telemetry systems, the Java programming language is typically not considered a viable option for embedded software development. Nevertheless, the Java platform provides many features that can easily be applied to embedded telemetry systems that other development platforms cannot match. But obviously, there are pitfalls to be aware of. This paper will present an alternative solution to address today’s problems in real-time telemetry systems and will cover the following topics: • Java development platforms for the embedded world • Impact on software portability and reusability • Performance and optimization techniques • Direct access to hardware devices • Memory management and garbage collection • Network-centric component-oriented architecture • Real-time examples from past experience • Future developments

      McWhorter, Mark; Honeywell Aerospace Electronic Systems (International Foundation for Telemetering, 2002-10)
      This paper discusses the effect of vehicle exhaust plasma/plume on the ability to receive telemetered data via an S-band RF link. The data discussed herein was captured during the launch of the QRLV-2 (Quick Reaction Launch Vehicle) on April 24, 2002 from Kodiak Launch Center, Kodiak, Alaska using Honeywell’s BMRST (Ballistic Missile Range Safety Technology) system.

      Sinclair, Robert; Beech, Russell; Jones, Kevin; Mundon, Scott; Jones, Charles H.; NVE Corporation.; Edwards Air Force Base (International Foundation for Telemetering, 2002-10)
      Replacing and maintaining sensors in existing legacy systems is costly and time consuming since no information beyond voltage or current is supplied by these sensors. When a sensor is replaced or added, information for that sensor has to be incorporated by the software programmer into the main system software – a costly and time-consuming process. A method has been developed to give these old sensors the intelligence to meet the requirements of the proposed IEEE P1451.3 standard. This is accomplished with no changes to the legacy hardware and a minor, one time change to the legacy main system software.

      Andrews, M. S.; TRW Radio Systems (International Foundation for Telemetering, 2002-10)
      The scope of the problem with generalized linear power amplifiers is herein addressed. In this paper, after an introduction to the problem of linearity and power amplifiers is addressed, a survey of various design issues from PA topology, materials, and linearization electronics is given. Following this, a look toward future work in this very active area of current research is also offered.

      Fike, Brian O’dell; Weiss, Michael A.; Ball Aerospace & Technologies Corp. (International Foundation for Telemetering, 2002-10)
      The GEOSAT Follow-On (GFO) Time Tag Correlation System (TTCS) was implemented as a ground-based time correlation system for precision time tagging of satellite data. This system uses simple ground hardware and software to convert satellite time to UTC, resulting in time tagging of payload data to within +/- 20 microseconds. The technique described in this paper eliminates the need for an on-board satellite Ultra-Stable Oscillator (USO) to achieve precision time tagging of satellite data and, therefore, can result in a significant cost savings to future missions.

      Thornér, Carl-Einar I.; Iltis, Ronald A.; University of California, Santa Barbara (International Foundation for Telemetering, 2002-10)
      The ISM bands have opened up new opportunities for telemetry using spread-spectrum communications. A low-cost frequency-hopping radio is described here for the 900 MHz ISM band that can be programmed with a wide range of hop and data rates. The ‘C6201 DSP from TI is used to control the frequency and data rate of the TI TRF6900 transceiver chip using a custom interface of the 6201 EVM board to the serial I/O on the 6900 evaluation board.

      Wheeler, Jim; Tape Restoration & Forensic Services (International Foundation for Telemetering, 2002-10)
      For the past thirty years, many people around the world have been engaged in studies to determine how long tape will last. We have learned how to extend the life of tapes but no one has come up with a method for predicting the life of a tape. This paper will summarize the present-day recommended practices for tape care and storage and will also describe the most common tape problems and how to overcome them. The most common problem with playing an old tape is finding a machine to play it. Machine obsolescence is probably a bigger problem than tape degradation.
    • Making All The Data Available Some Of The Time In Very Large Telemetry Volume Space Applications

      Cook, David B. (International Foundation for Telemetering, 2002-10)
      What do you do when your downlink telemetry needs outstrip your downlink bandwidth capability? The telemetry needed to support construction and operation of the largest, most complex engineering project ever undertaken, the International Space Station (ISS), already requires utilization of the full capacity of the downlink S-band capacity, yet there are additional systems and capabilities still to be added by NASA and the International Partners. The ISS Command and Telemetry Team has developed a method of swapping packets of telemetry that are intended for special operations, while simultaneously sending essential systems telemetry and less critical telemetry that is needed on a continuous basis. To support this attempt to “make available all of the data at least some of the time” the team developed concepts for grouping telemetry into families that would always be selected as a group and then created a set of metadata associated with these groups. This metadata is pre-defined to support automated selection and scrubbing of telemetry to correspond to major upgrades in the command and control software for the ISS. The new process will at least double the effective S-band downlink bandwidth. It will also provide automated selection, scrubbing, reporting and verification of telemetry selections.

      Lee, Hua; University of California (International Foundation for Telemetering, 2002-10)
      This paper presents a motion estimation and correction technique for the realization of synthetic-aperture sonar imaging. It utilizes the redundancy provided by the multiple-element receiver array and physical-array sub-images are used for the estimate the motion errors between adjacent receiver positions in the form of phase errors. Subsequently, motion errors can be corrected accordingly by making adjustments to the wavefield data samples prior to the formation of synthetic-aperture images.
    • Network Telemetry: Practical Experiences and Unique Features

      D’Amico, William P.; Stadter, Patrick A.; Lauss, Mark H.; Hooper, Andrew; Johns Hopkins University; Materiel Test Center (International Foundation for Telemetering, 2002-10)
      The US Army’s Yuma Proving Ground (YPG) uses a wireless local area network (WLAN) to gather test data. It is desired to extend this WLAN to support tests of gun-launched munitions where miniature and rugged data acquisition hardware will be required. The Two Way Robust Acquisition of Data (2-RAD) program has been initiated under the Central Test and Evaluation Investment Program (CTEIP) to develop a process to expand the use of WLAN technology, which is now primarily used at YPG for internal ballistic test data acquisition.

      Smith, Grant M.; Dewetron Inc. (International Foundation for Telemetering, 2002-10)
      Advances in several related technologies have brought together the previously incompatible goals of incorporating as much COTS technology as possible into the telemetry data recording architecture, providing operators with the kinds of real-time graphical data displays that they are accustomed to, and allowing these same data display systems to share data across a network and write to common database files accessible from centralized workstations.

      Mauldin, Kendall; New Mexico State University (International Foundation for Telemetering, 2002-10)
      A multi-platform network design that is automated, bi-directional, capable of store and forward operations, and low-bandwidth has been developed to connect multiple satellite ground stations together in real-time. The LabVIEW programming language has been used to develop both the server and client aspects of this network. Future plans for this project include implementing a fully operational ground network using the described concepts, and using this network for real-time satellite operations. This paper describes the design requirements, RF and ground-based network configuration, software implementation, and operational testing of the ground network.