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.
    • The Merging of Multisource Telemetry Data to Support Over the Horizon Missile Testing

      Peterson, Dwight M.; Naval Warfare Assessment Division (International Foundation for Telemetering, 1995-11)
      The testing of instrumented missile systems with extended range capabilities present many challenges to existing T&E and training ranges. Providing over-the-horizon (OTH) telemetry data collection and displaying portions of this data in real time for range safety purposes are just a few of many factors required for successful instrumented range support. Techniques typically used for OTH telemetry data collection are to use fixed or portable antennas installed at strategic down-range locations, instrumented relay pods installed on chase aircraft, and instrumented high flying relay aircraft. Multiple data sources from these various locations typically arrive at a central site within a telemetry ground station and must be merged together to determine the best data source for real time and post processing purposes. Before multiple telemetered sources can be merged, the time skews caused by the relay of down-range land and airborne based sources must be taken into account. The time skews are fixed for land based sources, but vary with airborne sources. Various techniques have been used to remove the time skews associated with multiple telemetered sources. These techniques, which involve both hardware and software applications, have been effective, but are expensive and application and range dependent. This paper describes the use of a personal computer (PC) based workstation, configured with independent Pulse Code Modulation (PCM) decommutators/bit synchronizers, Inner-Range Instrumentation Group (IRIG) timing, and data merging resident software to perform the data merging task. Current technology now permits multiple PCM decommutators, each built as a separate virtual memory expansion (VME) card, to be installed within a PC based workstation. Each land based or airborne source is connected to a dedicated VME based PCM decommutator/bit synchronizer within the workstation. After the exercise has been completed, data merging software resident within the workstation is run which reads the digitized data from each of the disk files and aligns the data on a bit by bit basis to determine the optimum merged result. Both time based and event based alignment is performed when merging the multiple sources.This technique has application for current TOMAHAWK exercises performed at the Air Force Development Test Center, Eglin Air Force Base (AFB), Florida and the Naval Air Warfare Center/Weapons Division (NAWC/WD), Point Mugu, California and future TOMAHAWK Baseline Improvement Program (TBIP) testing.

      Glenn, Tom; Chavez, Tomas; Toole, Michael T.; Markwardt, Jack (International Foundation for Telemetering, 1995-11)
      The Ballistic Missile Defense Organization (BMDO) is developing new Theater Missile Defense (TMD) weapon systems to defend against the rapidly expanding ballistic missile threat. The tactical ballistic missile threats include systems with range capabilities greater than 1000 kilometers. The development and testing of systems such as the Patriot Advanced Capability 3 (PAC-3), the Theater High Altitude Area Defense (THAAD), Navy Area Defense, and the System Integration Tests (SIT) to address the interoperability of this family of systems, will require the development of the Transportable Range Augmentation and Control System for Multiple Shot Engagements (TRACS - MSE). Congress has mandated that these systems be tested in multiple simultaneous engagements. These systems will be tested at several ranges to meet all the developmental and operational testers' needs. Potential range locations include White Sands Missile Range (WSMR), Kwajalein Missile Range (KMR), the Pacific Missile Range Facility (PMRF) and the Gulf Range at Eglin Air Force Base. Due to the long distances separating the target launch site and the interceptor site, the TRACS - MSE will be required at multiple sites for each range used. To be cost effective, transportable systems should be developed to augment existing capabilities. Advances in Global Positioning System (GPS) technology and high data rate receivers make telemetry based solutions attractive. This article will address the requirements for range safety, for Time, Space, Position Information (TSPI) collection and processing requirements to support a TRACS - MSE capability.

      Lange, Werner R.; Ravensbergen, Martin; LANGE-ELECTRONIC GMBH; EUROPEAN SOUTHERN OBSERVATORY (International Foundation for Telemetering, 1995-11)
      The necessity of supplying precise time information in large telemetry ground stations and astronomical observatories is very similar. Therefore the way of solving this problem as it is done in the Very Large Telescope of the European Southern Observatory can be easily adopted to telemetry stations and ranges, especially when fiber optics are used. The European Southern Observatory (ESO) is building a new observatory in Chile for the Very Large Telescope (VLT). This VLT consists of 4 telescopes, each of them has a primary mirror diameter of 8 meters. the control architecture is based on workstations and VMEbus computers. The VMEbus computers are distributed over the whole building and are using real time operating system. Since the availability of the Global Positioning System (GPS) the generation of highly accurate timing signals on remote locations without the use of expensive Cesium standards does not create problems any more. However, distribution of a timing signal to many computer with high accuracy is an issue. The accuracy of the commonly used IRIG B-code is not adequate if the requirements are in the 10 microseconds range. This paper presents the design of a timing system that is adopted to the VLT. An overview of the requirements of the Time Reference System (TRS) is given. These requirements have been defined on the basis of experiences with the timing system of the ESO NTT telescope. The hardware units are described. These are a Central Time Standard, a Time Distribution System and a VME Time Interface Module. The distribution is based on fiber optic transmission, using a simple digital modulation that outperforms the analog IRIG B modulation. The Time Interface Module in the computer does not only perform the timing signal decoding but contains also user-programmable timers that are synchronously clocked from the time source. Presently all units of the TRS have been tested and the series production of the distribution and the Time Interface Modules are in progress.
    • The Impact of Telemetry on Radio Astronomy

      Janes, Clinton C. (International Foundation for Telemetering, 1995-11)
      The National Radio Astronomy Observatory (NRAO) operates the Very Large Array (VLA) Radio Observatory in New Mexico, and the Very Long Baseline Array (VLBA) with 10 radio antenna in locations from Hawaii to St. Croix, as well as other radio telescopes at Green Bank, West Virginia, and the 12 meter radio antenna near Tucson, AZ. Although radio frequency (RF) bands have been set aside for passive use by these radio telescopes, harmful interference from increased demands on the radio spectrum is a growing problem for earth-based radio astronomy. For example, locating a radio observatory in a remote area is little defense from satellite downlink telemetry. This paper describes why the operation of the radio telescopes is susceptible to RF telemetry interference, what bands are particularly vulnerable and at what power levels, and how data collection and centralized control of the arrays are accomplished without RF telemetry.

      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.
    • 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.

      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.
    • 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.

      Mitchell, B. J.; The Johns Hopkins University (International Foundation for Telemetering, 1995-11)
      Recent narrow band imagery of the surface of Titan reveals a very non-uniform surface. While there are no global oceans of liquid ethane/methane as once conjectured, the imagery does suggest the possibility of seas or lakes of liquid ethane, methane, and other organic materials. If these exist, Titan could be considered a gigantic analog model of the Earth's climate system complete with land masses, moderately thick atmosphere, and large bodies of liquid. By studying the climate of Titan, we could gain further understanding of the processes and mechanisms that shape the Earth's climate. Reuse of existing technology and methods may be a way to speed development and lower costs for the global study of Titan. Surprisingly, one of the key technologies could be a Transit or Global Positioning System (GPS) descendant for use in tracking probes wandering the surface of Titan.

      Long, David G. (International Foundation for Telemetering, 1995-11)
      A radar scatterometer transmits a series of RF pulses and measures the total-power (energy) of the backscattered signal. Measurements of the backscattered energy from the ocean's surface can be used to infer the near-surface wind vector [7]. Accurate backscatter energy measurements are required to insure accurate wind estimates. Unfortunately, the signal measurement is noisy so a separate measurement of the noise-only total-power is subtracted from the signal measurement to estimate the echo signal energy. A common metric for evaluating the accuracy of the scatterometer energy measurement is the normalized signal variance, termed K(p). In designing a scatterometer tradeoffs in design parameters are made to minimize K(p). Spaceborne scatterometers have traditionally been based on fan-beam antennas and CW modulation for which expressions for K(p) exist. Advanced pencil-beam scatterometers, such as SeaWinds currently being developed by NASA use modulated Signals so that new K(p) expressions are required. This paper outlines the derivation of the generalized K(p) expression. While very complicated in its exact form, with a simplified geometry the K(p) expression can be related to the radar ambiguity function. The resulting analysis yields insights into the tradeoffs inherent in a scatterometer design and permits analytic tradeoffs in system performance.

      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.

      Biroscak, D.; Losik, L.; Malina, R. F. (International Foundation for Telemetering, 1995-11)
      The Extreme Ultraviolet Explorer (EUVE) Science Operations Center at UC Berkeley was recently successful in implementing an automated monitoring system that allowed reduced operations staffing from 24 hours per day to 9 hours per day. The payload safety is monitored exclusively by artificial intelligence (AI) telemetry-processing systems for 16 hours per day. At launch, the EUVE Science Operations Center was staffed and operated as a typical satellite control center, receiving real-time and tape recorder data 24 hours per day. From September 1993 through February 1995, EUVE science operations were redesigned in a phased, low-cost approach. A key factor in the implementation was to utilize existing personnel in new roles through additional training and reorganization. Through- out this period, EUVE guest observers and science data collection were unaffected by the transition in science operations. This paper describes the original and actual implementation plan, staffing phases, and cost savings for this project. We present the lessons learned in the successful transition from three-shift to one-shift operations.
    • Integrated CCSDS, SGLS and STDN Telemetry, Tracking and Command Processing System

      Nichols, Alex; Goodstein, F. Robert; VanCouvering, Ken; TRW Components International; TRW Inc. (International Foundation for Telemetering, 1995-11)
      This paper describes the use of an open architecture, low-cost, turnkey Telemetry, Tracking and Command (TT&C) processor system. The workstation based system was developed to satisfy the requirement for ground station equipment to handle and process multiple vehicle platforms for telemetry, command and tracking (tone or PRN), including STDN, SGLS and CCSDS link formats. The open architecture of the system allows for easy interface with external equipment for control of antenna systems, encryption units and other related station equipment. Reconfiguration for the various data formats and for system verification is done through a graphical user interfaces using operationally proven commercial-off-the-shelf (COTS) software and hardware. The open architecture of the system will allow for modifications and upgrades to be cost effective.

      Olyniec, Lee; Edwards Air Force Base (International Foundation for Telemetering, 1995-11)
      This paper describes the design and characteristics of a digital voice encoding circuit that uses the continuously variable slope delta (CVSD) modulation/demodulation method. With digital voice encoding, the audio signal can be placed into the pulse code modulation (PCM) data stream. Some methods of digitizing voice can require a large amount of bandwidth. Using the CVSD method, an acceptable quality of audio signal is obtained with a minimum of bandwidth. Presently, there is a CVSD microchip commercially available; however, this paper will describe the design of a circuit based on individual components that apply the CVSD method. With the advances in data acquisition technology, increased bit rates, and introduction of a corresponding MIL-STD, CVSD modulated voice will become more utilized in the flight test programs and a good knowledge of CVSD will become increasingly important. This paper will present CVSD theory, supported by graphical investigations of a working circuit under different conditions. Finally, several subjects for further study into CVSD will be addressed.

      Hicks, William T.; Aydin Vector Division (International Foundation for Telemetering, 1995-11)
      The desire to acquire large quantities of high speed vibration and acoustic data during aircraft testing is usually satisfied through on-board high speed recording methods. However there is often a need to have some of this data instantly available at the ground station for flight safety and other purposes. A Data Processor (DP) has been developed allowing an airborne data acquisition system to acquire large amounts of wideband analog data, process the data in real-time, and develop reduced bandwidth information from high bandwidth channels. The reduced data can be inserted into a Pulse Code Modulation (PCM) stream and telemetered via a Radio Frequency (RF) link with a potential for a 2000:1 reduction in bandwidth. This on-board processing capability also lends itself to additional tasks such as the generation of a reduced bandwidth marker channel which can flag critical time periods of data activity. This flagging technique can be used to facilitate ground station analysis of specific segments of data, resulting in significant cost and time savings.

      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.

      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.

      Chesney, James R.; Bakos, Roger; TSI TelSys, Inc. (International Foundation for Telemetering, 1995-11)
      The remote sensing industry is experiencing an unprecedented rush of activity to deploy commercial and scientific satellites. NASA and its international partners are leading the scientific charge with The Earth Observation System (EOS) and the International Space Station Alpha (ISSA). Additionally, there are at least ten countries promoting scientific/commercial remote sensing satellite programs. Within the United States, commercial initiatives are being under taken by a number of companies including Computer Technology Associates, Inc., EarthWatch, Inc., Space Imaging, Inc., Orbital Imaging Corporation and TRW, Inc. This activity is due to factors including: technological advances which have lead to significant reductions in the costs to build and deploy satellites; an awareness of the importance of understanding human impact on the ecosystem; and a desire to collect and sell data some believe will be worth $1.5 billion (USD) per year within five years. The success and usefulness of these initiatives, both scientific and commercial, depends largely on the ease and cost of providing remotely sensed data to value added resellers and end-users. A number of these spacecraft will provide an interface directly to users. To provide these data to the largest possible user base, ground station equipment must be affordable and the data must be distributed in a timely manner (meaning seconds or minutes, not days) over commercial network and communications equipment. TSI TelSys, Inc. is developing ground station equipment that will perform both traditional telemetry processing and the bridging and routing functions required to seamlessly interface commercial local- and wide-area networks and satellite communication networks. These products are based on Very Large Scale Integration (VLSI) components and pipelined, multi-processing architectures. This paper describes TelSys’ product family and its envisioned use within a ground station.
    • A Low-Cost, Autonomous, Ground Station Operations Concept and Network Design for EUVE and Other Earth-Orbiting Satellites

      Abedini, A.; Moriarta, J.; Biroscak, D.; Losik, L.; Malina, R. F. (International Foundation for Telemetering, 1995-11)
      The Extreme Ultraviolet Explorer (EUVE) satellite was designed to operate with the Tracking and Data Relay Satellite System (TDRSS) and Deep Space Network (DSN). NASA, the Jet Propulsion Laboratory and the Center for EUV Astrophysics have been evaluating a commercially available ground station already used for NASA's Low Earth Orbit (LEO) weather satellites. This ground station will be used in a network of unattended, autonomous ground stations for telemetry reception, processing, and routing of data over a commercial, secure data line. Plans call for EUVE to be the initial network user. This network will be designed to support many TDRSS/DSN compatible missions. It will open an era of commercial, low-cost, autonomous ground station networks. The network will be capable of supporting current and future NASA scientific missions, and NASA's LEO and geostationary weather satellites. Additionally, it could support future, commercial communication satellites in low, and possibly medium, Earth orbit. The combination of an autonomous ground station and an autonomous telemetry monitoring system will allow reduction in personnel. The EUVE Science Operations Center has already reduced console work from three shifts to one by use of autonomous telemetry monitoring software.