• 0-Hz-IF FSK/AM Sub-Carrier Demodulator on a 6U-VME-Card

      Weitzman, Jonathan M.; GDP Space Systems (International Foundation for Telemetering, 1996-10)
      Aerospace Report No. TOR-0059(6110-01)-3, section 1.3.3 outlines the design and performance requirements of SGLS (Space Ground Link Subsystem) services. GDP Space Systems has developed a single card slot FSK (Frequency Shift Keying)/AM (Amplitude Modulation) demodulator. An application of this service is the US Air Force Satellite Command and Ranging System. The SGLS signal is tri-tone-FSK, amplitude modulated by a modified triangle wave at half the data rate. First generation FSK/AM demodulators had poor noise performance because the signal tones were filtered and processed at IF frequencies (65, 76 and 95 kHz). Second generation demodulators suffer from "threshold" due to non-linear devices in the signal path before the primary noise filtering. The GDP Space Systems demodulator uses a 0-Hz- IF topology and avoids both of these shortcomings. In this approach, the signal is first noncoherently down converted to baseband by linear devices, then it is filtered and processed. This paper will discuss the GDP 0-Hz-IF FSK/AM (SGLS) demodulator.
    • 300 MBPS CCSDS Processing Using FPGA's

      Genrich, Thad J. (International Foundation for Telemetering, 1996-10)
      This paper describes a 300 Mega Bit Per Second (MBPS) Front End Processor (FEP) prototype completed in early 1993. The FEP implements a patent pending parallel frame synchronizer (frame sync) design in 12 Actel 1240 Field Programmable Gate Arrays (FPGA's). The FEP also provides (255,223) Reed-Solomon (RS) decoding and a High Performance Parallel Interface (HIPPI) output interface. The recent introduction of large RAM based FPGA's allows greater high speed data processing integration and flexibility to be achieved. A proposed FEP implementation based on Altera 10K50 FPGA's is described. This design can be implemented on a single slot 6U VME module, and includes a PCI Mezzanine Card (PMC) for a commercial Fibre Channel or Asynchronous Transfer Mode (ATM) output interface module. Concepts for implementation of (255,223) RS and Landsat 7 Bose-Chaudhuri-Hocquenghem (BCH) decoding in FPGA's are also presented. The paper concludes with a summary of the advantages of high speed data processing in FPGA's over Application Specific Integrated Circuit (ASIC) based approaches. Other potential data processing applications are also discussed.
    • 8PSK Signaling Over Non-Linear Satellite Channels

      Caballero, Rubén; New Mexico State University (International Foundation for Telemetering, 1996-10)
      Space agencies are under pressure to utilize better bandwidth-efficient communication methods due to the actual allocated frequency bands becoming more congested. Budget reductions is another problem that the space agencies must deal with. This budget constraint results in simpler spacecraft carrying less communication capabilities and also the reduction in staff to capture data in the earth stations. It is then imperative that the most bandwidth efficient communication methods be utilized. This paper gives the results of a computer simulation study on 8 Level Phase Shift Keying (8PSK) modulation with respect to bandwidth, power efficiency, spurious emissions, interference susceptibility and the non-constant envelope effect through a non-linear channel. The simulations were performed on a Signal Processing Worksystem (SPW: software installed on a SUN SPARC 10 Unix Station and Hewlett Packard Model 715/100 Unix Station). This work was conducted at New Mexico State University (NMSU) in the Center for Space Telemetry and Telecommunications Systems in the Klipsch School of Electrical and Computer Engineering.
    • ACTS Propagation Experiment and Solar/Lunar Intrusions

      Gardner, Christopher S.; New Mexico State University (International Foundation for Telemetering, 1996-10)
      In this paper are described the effects that solar and lunar intrusions have on statistical analysis of the data. The NASA ACTS experiment focuses on the 20 and 27 GHz radiometer and beacon. The experiment is currently compiling a database for the attenuation for these different channels. For the year of 1994 our sight obtained 86.5 hours of attenuation and for 1995 our sight obtained 77 hours of attenuation. The total amount of interference time for sun/lunar intrusions for 1994 and 1995 was respectively, 39 hours and 38.5 hours, which is nearly half the total amount of attenuation due to rain and cloud fades. It is clear to see why this data must be taken out for any type of statistical analysis of the data.
    • Advanced Range Telemetry (ARTM): Preparing for a New Generation of Telemetry

      Chalfant, Timothy A.; Straehley, Erwin H.; Switzer, Earl R. (International Foundation for Telemetering, 1996-10)
      At open air test and training ranges, telemetry is beset by two opposing forces. One is the inexorable demand to deliver more information to users who must make decisions in ever shorter time frames. The other is the reduced availability of radio frequency spectrum, driven by its increased economic value to society as a whole. ARTM is planned to assure that test and training programs of the next several decades can meet their data quantity and quality objectives in the faces of these challenges. ARTM expects to improve the efficiency of spectrum usage by changing historical methods of acquiring telemetry data and transmitting it from systems under test to range customers. The program is initiating advances in coding, compression, data channel assignment, and modulation. Due to the strong interactions of these four dimensions, the effort is integrated in a single focused program. In that these are problems which are common throughout the test and training community, ARTM is a tri-service program embodying the DoD's Common Test and Training Range Architecture and Reliance principles in its management and organization. This paper will discuss the driving forces, the initial study areas, the organizational structure, and the program goals.
    • Analysis of the Effects of Sampling Sampled Data

      Hicks, William T.; Drexel University (International Foundation for Telemetering, 1996-10)
      The traditional use of active RC-type filters as anti-aliasing filters in Pulse Code Modulation (PCM) systems is being replaced by the use of Digital Signal Processing (DSP) filters, especially when performance requirements are tight and when operation over a wide environmental temperature range is required. In order to keep systems more flexible, it is often desired to let the DSP filters run asynchronous to the PCM sample clock. This results in the PCM output signal being a sampling of the output of the DSP, which is itself a sampling of the input signal. In the analysis of the PCM data, the signal will have a periodic repeat of a previous sample, or a missing sample, depending on the relative sampling rates of the DSP and the PCM. This paper analyzes what effects can be expected in the analysis of the PCM data when these anomalies are present. Results are presented which allow the telemetry engineer to make an effective value judgment based on the type of filtering technology to be employed and on the desired system performance.

      Pedroza, Moises; White Sands Missile Range (International Foundation for Telemetering, 1996-10)
      The use of high bit rates in the missile testing environment requires that the receiving telemetry system(s) have the correct signal margin for no PCM bit errors. This requirement plus the fact that the use of “redundant systems” are no longer considered optimum support scenarios has made it necessary to select the minimum number of tracking sites that will gather the data with the required signal margin. A very basic link analysis can be made by using the maximum and minimum gain values from the transmitting antenna pattern. Another way of evaluating the transmitting antenna gain is to base the gain on the highest percentile appearance of the highest gain value. This paper discusses the mathematical analysis the WSMR Telemetry Branch uses to determine the signal margin resulting from a radiating source along a nominal trajectory. The mathematical analysis calculates the missile aspect angles (Theta, Phi, and Alpha) to the telemetry tracking system that yields the transmitting antenna gain. The gain is obtained from the Antenna Radiation Distribution Table (ARDT) that is stored in a computer file. An entire trajectory can be evaluated for signal margin before an actual flight. The expected signal strength level can be compared to the actual signal strength level from the flight. This information can be used to evaluate any plume effects.

      Wentai, Feng; Biao, Li; Xinan Electronic Engineering Institute (International Foundation for Telemetering, 1996-10)
      It is well known that the pulse telemetering system whose system equipment is simple is superior to the continuous one in ultilizing signal power. But in designing a pulse telemetering receiver the frequency shift problem is often encountered, the shift often greatly wider than the signal bandwidth is very unfavorable for improving receiver working sensitivity. Either to limit transmitter frequency stability strictly or to adapt AFC system in receiver for tracking carrier wave can solve the problem above, the AFC system method could improve the receiver’s performance, but the equipment is complicated. To what extent the receiver working sensitivity will be effected and how to judge the effection in case of adapting VF matched filter and RF being wideband in receiver are this paper’s emphasis. In this paper the power density spectrum distribution of the white noise which has passed through the non-linear system-the linear detector is analysed theoretically, and the improved working sensitivity of the receiver with video matched filter and its difference sensitivity value to that of the optimal receiver are derived. The tested working sensitivity data of two kind pulse receivers with different RF bands are given and the theoretical calculation results conform well with these data, thus it is proven that adapting video matched filter in pulse receiver is a effective approach for compensating the receiver working sensitivity dropping from RF bandwidth increase.

      Schumacher, Gary A.; Terametrix Systems International, Inc. (International Foundation for Telemetering, 1996-10)
      PC based instrumentation and telemetry processing systems are attractive because of their ease of use, familiarity, and affordability. The evolution of PC computing power has resulted in a telemetry processing system easily up to most tasks, even for control of and processing of data from a very complex system such as the Common Airborne Instrumentation System (CAIS) used on the new Lockheed-Martin F-22. A complete system including decommutators, bit synchronizers, IRIG time code readers, simulators, DACs, live video, and tape units for logging can be installed in a rackmount, desktop, or even portable enclosure. The PC/104 standard represents another step forward in the PC industry evolution towards the goals of lower power consumption, smaller size, and greater capacity. The advent of this standard and the availability of processors and peripherals in this form factor has made possible the development of a new generation of portable low cost test equipment. This paper will outline the advantages and applications offered by a full-function, standalone, rugged, and portable instrumentation controller. Applications of this small (5.25"H x 8.0"W x 9.5"L) unit could include: flight line instrumentation check-out, onboard aircraft data monitoring, automotive testing, small craft testing, helicopter testing, and just about any other application where small-size, affordability, and capability are required.
    • Applications of a Telemetry Signal Simulator

      O’Cull, Douglas; Microdyne Corporation (International Foundation for Telemetering, 1996-10)
      This paper will discuss the use of a specialized telemetry signal simulator for pre-mission verification of a telemetry receiving system. This will include how to configure tests that will determine system performance under “real time” conditions such as multipath fading and Doppler shifting. The paper will analyze a telemetry receiving system and define tests for each part of the system. This will include tests for verification of the antenna system. Also included, will be tests for verification of the receiver/combiner system. The paper will further discuss how adding PCM simulation capabilities to the signal simulator will allow testing of frame synchronizers and decomutation equipment.
    • Automated Generation of Telemetry Formats

      Jones, Charles H.; Gardner, Lee S.; Edwards Air Force Base (International Foundation for Telemetering, 1996-10)
      The process of generating a telemetry format is currently more of an ad-hoc art than a science. Telemetry stream formats conform to traditions that seem to be obsolete given today's computing power. Most format designers would have difficulty explaining why they use the development heuristics they use and even more difficulty explaining why the heuristics work. The formats produced by these heuristics tend to be inefficient in the sense that bandwidth is wasted. This paper makes an important step in establishing a theory on which to base telemetry format construction. In particular it describes an O(nlog n) algorithm for automatically generating telemetry formats. The algorithm also has the potential of efficiently filling a telemetry stream without wasting bits.

      Anderson, Christopher; Cincinnati Electronics (International Foundation for Telemetering, 1996-10)
      With every new spacecraft that is designed comes a greater density of information that will be stored once it is in operation. This, coupled with the desire to reduce the number of ground stations needed to download this information from the spacecraft, places new requirements on telemetry transmitters. These new transmitters must be capable of data rates of 320 Mbps and beyond. Although the necessary bandwidth is available for some non-bandwidth-limited transmissions in Ka-Band and above, many systems will continue to rely on more narrow allocations down to X-Band. These systems will require filtering of the modulation to meet spectral limits. The usual requirements of this filtering also include that it not introduce high levels of inter-symbol interference (ISI) to the transmission. These constraints have been addressed at CE by implementing a DSP technique that pre-filters a QPSK symbol set to achieve bandwidth-limited 320 Mbps operation. This implementation operates within the speed range of the radiation-hardened digital technologies that are currently available and consumes less power than the traditional high-speed FIR techniques.

      Knoebel, Robert; Berdugo, Albert; Aydin Vector Division (International Foundation for Telemetering, 1996-10)
      The Common Airborne Instrumentation System (CAIS) was developed under the auspices of the Department of Defense to promote standardization, commonality, and interoperability among flight test instrumentation. The central characteristic of CAIS is a common suite of equipment used across service boundaries and in many airframe and weapon systems. The CAIS system has many advanced capabilities which must be tested during ground support and system test. There is a need for a common set of low cost, highly capable ground support hardware and software tools to facilitate these tasks. The ground support system should combine commonly available PC-based telemetry tools with unique devices needed for CAIS applications (such as CAIS Bus Emulator, CAIS Hardware Simulator, etc.). An integrated software suite is imperative to support this equipment. A CAIS Ground Support Unit (GSU) has been developed to promote these CAIS goals. This paper presents the capabilities and features of a PC-based CAIS GSU, emphasizing those features that are unique to CAIS. Hardware tools developed to provide CAIS Bus Emulation and CAIS Hardware Simulation are also described.

      Guadiana, Juan M.; Rivera, Jesus; Jedlicka, Russel; White Sands Missile Range; New Mexico State University (International Foundation for Telemetering, 1996-10)
      The effects of multipath in telemetry applications are very well known and the approaches to minimizing these effects are the subject of countless books, papers and articles. Multipath once again rears its head as the U.S. Navy fields the MK-41 Vertical Launching System (VLS), a launching system in which each missile is housed in a canister which is both magazine and launch mechanism. The Canister is designed to protect the missile from Electro Magnetic Interference (EMI), Radio Frequency Interference (RFI) and the environment. As can be expected, a canister designed to prevent Radio Frequency (RF) energy from entering should inherently prevent any RF from escaping, and renders the canister environment ripe with multipath. Pre-Launch telemetry checks, essential to the conduct of a missile flight test, become unreliable events which at times result in aborted missions. Today the “encanistered” missile system enjoys wide acceptance, in the U.S. as well as internationally. Since any missile radiating in a closed volume inherently suffers from these multipath degradations, it is important to disclose the results of Navy testing conducted on the canister as well as the mission observations of the multipath effects. The mission observations are described are “signature” traits of the degradations which should have been attributed to multipath. Clearly many missions and tests were affected, but most were simply ignored by an oblivious test team. A short summary of the canister multipath investigation follows,including unexpected findings, and finally a discussion is given on the Close Coupled Antenna and its effectiveness in mitigating the canister multipath.
    • Capture Method for Spread Spectrum Aloha Signals

      Weibing, Fan; Qishan, Zhang; Beijing University of Aero & Astro. (International Foundation for Telemetering, 1996-10)
      The concept and model of Spread Spectrum ALOHA (SS-ALOHA), as an important subject to develop dual-purpose satellite system in China, are described in this paper. The new synchronous code format and method for capturing the SS-ALOHA signals are presented and the process of correlation with surface-audio wave (SAW) is shown. The diagram of fast acquisition system and the results of experiment are given.
    • The Challenge of Programmed Tracking Low Orbit Satellites from Mobile Ground Stations

      Hoecht, Dietrich; Scientific Atlanta Inc. (International Foundation for Telemetering, 1996-10)
      Orbiting satellites can be tracked by following preprogrammed ephemeris data in the ground station controller. This tracking method is advantageous, because of the reduced acquisition cost of non-autotracking receiver and antenna feed components. Further, widely separated frequency bands can readily be tracked, without the complexity of a frequency specific auto-track system. Two types of mobile tracking systems are described. They are composed of elevation-over-azimuth-over-tilt and of an X-Y axis pedestal configuration. The calibration methods for establishing time and geographical references are discussed, as well as the challenges of minimizing the effects of system and environment induced error contributors.

      de Silveira, Carl; California Institute of Technology (International Foundation for Telemetering, 1996-10)
      As we adopt and implement the doctrines of reengineering, we at NASA/Jet Propulsion Laboratory (JPL) are asked to make a giant leap in how we think of and design SpaceCraft. We call what we are doing a revolution, since we are not “evolving” to the next step in our activity, but literally leaping beyond it. This is fully in concert with the concepts of reengineering, in that areas that need to be changed are indeed literally invented anew. To be successful, JPL and its industry partners, must perfect processes, techniques and methods that allow them to work together at all levels of the SpaceCraft development cycle. If all other parts of the discipline have moved on and changed, but a key portion remains locked in a time warp of yesterday, we will not be able to reach our desired goal. At the present time change is occurring all over JPL, and it is our intent to describe how it applies to areas where prototype, or one of a kind hardware are fabricated, and how these areas might look when new approaches to doing business are applied. Since all activities in an organization must attain similar levels of expertise or be in danger of hampering the entire process, the issues of Packaging Engineering, Manufactureability, and fabrication become key items.

      Hogie, Keith; Weekley, Jim; Jacobsohn, Jeremy (International Foundation for Telemetering, 1996-10)
      The world of data communication and networking has grown rapidly over the last decade, and this growth has been accompanied by the development of standards that reflect and facilitate the need for commercial products that work together in a reliable, robust, and coherent fashion. To a great extent this commercialization, with its increasing performance and diminishing cost, has not been adapted to the data communication needs of satellites. As budgets and mission development and deployment timelines shrink, space exploration and science will require the development of standards and the use of increasing amounts of off-the-shelf hardware and software for integrated satellite ground systems. The Renaissance project at NASA/Goddard Space Flight Center has engaged in rapid prototyping of ground systems using off-the-shelf hardware and software products to identify ways of implementing satellite ground systems "faster, better, cheaper". This paper presents various aspects of these activities, including issues related to the configuration and integration of current off-the-shelf products using telemetry databases for existing spacecraft, an analysis of issues related to the development of standard products for satellite communication, tradeoffs between hardware and software approaches to performing telemetry front-end processing functions, and proposals for future standards and development.

      Homan, Rodney M.; Naval Air Warfare Center, Aircraft Division (International Foundation for Telemetering, 1996-10)
      The Department of Defense (DoD), through a Tri-Service Program Office, is developing the Common Airborne Instrumentation System (CAIS) to promote standardization, commonality, and interoperability among aircraft test instrumentation systems. The advent of CAIS will change how the DoD test community conducts business. The CAIS program will allow aircraft test and evaluation facilities to utilize common airborne systems, ground support equipment, and technical knowledge for airborne instrumentation systems. The CAIS Toolset Software (CTS) provides the capability to generate formats and load/verify airborne memories. The CTS is primarily a software applications program hosted on an IBM compatible portable personal computer with several interface cards. The software will perform most functions without the presence of the interface cards to allow the user to develop test configurations and format loads on a desktop computer.
    • Communication System Applications for Shipboard Data Collection and Networking

      Peterson, Dwight M.; Instrumentation Systems (International Foundation for Telemetering, 1996-10)
      The assessment of weapons and combat system performance requires the collection and networking of data from shipboard and land based locations. New programs being introduced and tested, such as the Cooperative Engagement Capability, Theater Ballistic Missile Defense, and All Service Combat Identification Evaluation Team, generate gigabytes of data which must be reduced, transferred, and analyzed. Test conductors, headquarters personnel, and military commanders require analysis results in near real time to evaluate system performance during a test or exercise. This paper will discuss communication system applications for shipboard data collection and networking to collect, reduce, and transfer the large amounts of data generated during current and planned Navy and Joint exercises. Examples of using 56 Kbit/Second International Maritime Satellite, range based line-of-sight networking, and integrated workstation applications will be addressed and lessons learned shared from actual installation and use.