Eslinger, Brian; McCombe, Joleen; Edwards Air Force Base (International Foundation for Telemetering, 1997-10)
      The growing need to transmit larger telemetry streams from the receiving site to the processor location over greater distances is requiring newer and more creative techniques. This paper reports efforts to use Asynchronous Transfer Mode (ATM) technology and inverse multiplexing to provide an economical system to interface telemetry streams into the public network for reliable transmission. Cost savings are available immediately for programs that are willing to meet the synchronization criteria today. Lab testing has shown the feasibility of using cost efficient techniques for data transmission. This document describes the investigation that is currently underway that could provide a significant change to the way telemetry data is transmitted from receiver sites to data processing sites. Instead of using dedicated lines with dedicated bandwidth regardless of the program being supported, the approach that has been tested in a lab environment would allow the dynamic allocation of bandwidth using ATM over a variety of carrier services. The combination of ATM and inverse multiplexing allows telemetry data rates above 1.5 Megabits per second (Mbps) to be transmitted over multiple T1 (1.544 Mbps) lines. Previously, the only choice when data rates exceeded 1.5 Mbps was to use an entire DS-3 (45 Mbps). Now it is possible to transmit intermediate sized data rates (1.5 to 8 Mbps) by bonding multiple T1s to provide the desired data throughput.
    • The Use of Telemetry in Heavy Equipment Testing at Caterpillar Inc.

      Chapman, James E.; Caterpillar Inc. (International Foundation for Telemetering, 1997-10)
      Caterpillar has for many years used telemetry as a key component in the data acquisition and analysis systems used to test and develop heavy equipment. The testing of construction and mining equipment at Caterpillar presents several unique challenges, such as the operating environment of the test machine, the large number of models in the product line, the need to change test machines on a daily basis, and the need to test machines at job sites throughout North America. These challenges have resulted in the development of telemetry, data acquisition and data analysis systems that have been highly customized to meet all of our requirements for construction equipment testing. This paper describes the past history of telemetry use at Caterpillar, from early FM/FM systems to our current PC/Unix based PCM/FM system, the criteria used to develop these systems, and how our current telemetry system is being used today to help develop and test product.
    • Burst Analysis of Bit Errors on an F-16 Test Flight at Edwards AFB

      Rice, Michael; Welling, Kenneth; Landon, David; Brigham Young University (International Foundation for Telemetering, 1997-10)
      Bit errors induced by multipath interference occur in short bursts with relatively long intervals of error-free propagation. This paper analyzes the bursty nature of bit errors by examining synthetic error sequences generated from received voltage levels measured during low-altitude F-16 flights at Edwards AFB. The error gap distribution (which is a cumulative distribution function of the length of the error free intervals) and the block error probability are computed from the data. These parameters are useful in assessing the performance of error control coding strategies.

      Rice, Michael; Perrins, Erik; Brigham Young University (International Foundation for Telemetering, 1997-10)
      The Advanced Communication Technology Satellite (ACTS) Mobile Terminal (AMT) has been deployed aboard the USS Princeton (CG 59) in an experiment to test the viability of K and Ka band technology in military communication applications. Pilot tone data recorded on-board the USS Princeton (CG 59) show that most variations in the received power level result from antenna tracking errors and did not appear to be caused by obstructions from the ship superstructure. The data also showed that multipath interference was negligible. The data studied in this paper were gathered during ship maneuvers in the Caribbean (13E 33’ N, 76E 16’ W) in late May 1997 and in the Eastern Pacific (6E 34’ N, 79E 40’ W) in early June 1997. The relationship between pitch/yaw/roll and received power levels is studied. Plots showing received power (time series) are presented to aid in link budget calculations.

      Honglin, Zhao; Shijie, Bi; Tingxian, Zhou (International Foundation for Telemetering, 1997-10)
      This paper analyzes the performance of an M-ary spread spectrum system with orthogonal codes. A new scheme of M-ary spread spectrum communication with phase shifted msequence is proposed, and the method to implement code synchronization in the scheme is given. The performance of the new scheme is analyzed, and compared to conventional spread spectrum systems and orthogonal code M-ary systems. The results show that stronger anti-interference ability, and better data transmission efficiency, and lower complexity is achieved in the system employing phase shifted m-sequence.

      Grant, Eugene; Coleman Research Corporation (International Foundation for Telemetering, 1997-10)
      A target missile is a unique piece of test hardware. This test tool must be highly reliable, low cost and simple and must perform any task that the developing interceptor missile planners require. The target missile must have ample power and guidance resources to put the target in a specified place in the sky at a desired time. The telemetry and measurement system for the target missile must have the same requirements as its interceptor missile but must be flexible enough to accept new requirements as they are applied to the target and its interceptor. The United States Army has tasked Coleman Aerospace to design and build this type of target missile. This paper describes and analyzes the telemetry and instrumentation system that a Hera target missile carries. This system has been flying for the past two years, has completed seven out of seven successful test flights and has accomplished all test objectives to date. The telemetry and instrumentation system is an integral part of the missile self-test system. All preflight checks and flight simulations are made with the on-board three-link telemetry system through a radio frequency (RF) link directly through the missile antenna system to a ground station antenna. If an RF transmission path is not available due to test range restrictions, a fiber-optic cable links the pulse code modulator (PCM) encoder to the receiving ground stations which include the bitsync, decommutator and recorders. With this capability, alternative testing is not limited by RF test range availability. The ground stations include two mobile stations and a factory station for all testing including preflight testing of the missile system prior to flight test launches. These three ground stations are built in a single configuration with additional equipment in the mobile units for use at remote locations. The design, fabrication, testing and utilization of these ground stations are reviewed. The telemetry system is a modification of the classical PCM system and will operate with its interceptor missile at least into the first decade from the year 2000.

      Shubo, Jin; Yanshan, Zhao; Xinan Electronic Engineering Institute (International Foundation for Telemetering, 1997-10)
      This paper describes a kind of Microwave Digital Frequency Synthesizer used for S-band telemetry receivers. As well known many modern electronic systems employ a Frequency Synthesizer whose spectral purity is critical. The characteristics of a PLL (Phase-Locked Loop) Frequency Synthesizer, such as frequency resolution, phase noise, spurious suppression and switch time, should be compromised in our design. A heterodyne Frequency Synthesis is often considered as a good approach to solve the problem. But it is complicated in structure and circuit. A variable-reference-driven PLL Frequency Synthesizer was introduced which can give an improved trade-off among frequency resolution, phase noise, spurious suppression. In this paper the phase noise and spurious suppression characteristic of variable-reference-driven PLL Frequency Synthesizer is analyzed theoretically and compared with that of the heterodyne Frequency Synthesizer. For engineering application, a practical Microwave Digital Frequency Synthesizer used for telemetry receiver has been designed, which is characterized by simply structure, low phase noise and low spurious output. The output spectrum of experimental measurements is given.

      Peart, David E.; Talbert, Jim; Lockheed Martin Vought Systems (International Foundation for Telemetering, 1997-10)
      In recent years we have seen an increase in the use of MIL-STD-1553 buses and other asynchronous data sources used in new missile and launcher designs. The application of multiplexed asynchronous buses in missiles and launchers is very common today. With increasing application of asynchronous data sources into very complex systems the need to acquire, analyze, and present one hundred percent of the bus traffic in real time or near real time has become especially important during testing and diagnostic operations. This paper discusses ways of converting asynchronous data, including MIL-STD-1553, into a telemetry format that is suitable for encryption, telemetering, recording, and presenting with Inter Range Instrumentation Group (IRIG) compatible off-the-shelf hardware. The importance of these designs is to provide the capability to conserve data bandwidth and to maximize the use of existing hardware. In addition, this paper will discuss a unique decode and time tagging design that conserves data storage when compared to the methods in IRIG Standard 106-96 and still maintains a very accurate time tag.

      Law, Eugene; Feher, Kamilo; NAWCWPNS; University of California, Davis; Digcom, Inc. (International Foundation for Telemetering, 1997-10)
      The aeronautical telemetry community is investigating alternative modulation methods to the commonly used non-return-to-zero (NRZ) pulse code modulation (PCM)/frequency modulation (FM). This paper outlines the important characteristics being investigated. Measured data comparing the spectral occupancy and bit error probability (BEP) performance of PCM/FM with that of a prototype constant envelope Feher’s quadrature phase shift keying (FQPSK) modulator and demodulator will also be presented. Measured results in several radio frequency bands demonstrate that the 99.99% and -60 dBc bandwidths of filtered FQPSK are only approximately one-half of the corresponding bandwidths of optimized PCM/FM even when the signal is non-linearly amplified. The signal energy per bit to noise power spectral density (E /N ) required for a BEP of 1×10 b 0 -5 for non-optimized FQPSK was approximately 12 dB which is approximately the same as limiter discriminator detected PCM/FM.

      Chalfant, Timothy A.; Irving, Charles E.; Edwards Air Force Base (International Foundation for Telemetering, 1997-10)
      The system throughput capacities of modern data systems exceed the bit rate capacity of current range telemetry capabilities. Coupling this with the shrinking spectrum allocated for telemetry results in a serious problem for the Test, Training, and Space telemetry users. Acknowledging this problem, the Department of Defense (DoD) has embarked on an aggressive improvement and modernization program that will benefit both the government and commercial range providers and users. The ADVANCED RANGE TELEMETRY (ARTM) program was created and funded by the Central Test and Evaluation Investment Program (CTEIP) under the Office of the Secretary of Defense, Undersecretary for Acquisition and Technology to address this problem. The ARTM program goals are 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 into a single focused program. This paper describes the ARTM program and how academia research, emerging technology, and commercial applications will lay the foundation for future development.

      MacDougall, Christopher; Bombardier Flight Test Center (International Foundation for Telemetering, 1997-10)
      During engine and airfield performance testing it is often necessary to acquire weather data at the airfield where the test is being conducted. The airborne data acquisition system (DAS) acquires data associated with flight parameters. A separate system records airport weather conditions. Many times the separate system is an Automated Terminal Information Service (ATIS) or the ground crew relaying wind speed, wind direction and temperature from a weather station. To improve this system, the weather station is designed to acquire and store the data in memory. Utilizing a second DAS that is remote to the airborne DAS poses several problems. First, it is undesirable to have many different data acquisition systems from which to process data. The problem then develops into one of integrating the ground weather DAS with the existing airborne DAS. Other problems of system integrity, compatibility and FCC licensing exist. Complete system integration while maintaining integrity and compatibility is overcome by controlling signal format, flow and timing and is discussed in detail. Further discussion of the issue of transmission is overcome by a technique called spread-spectrum and is used in accordance with FCC rules and regulations.

      Buckingham, Gary A.; Corey, Garth P.; U.S. Department of Energy; Sandia National Laboratories (International Foundation for Telemetering, 1997-10)
      The vast majority of all utility power quality problems consist of short duration surges, sags, and momentary power losses that wreak havoc among modern sensitive loads. To solve these power quality problems, a highly reliable, low-cost battery solution, the AC Battery PQ2000, developed with Department of Energy and Sandia National Laboratories assistance, is now available to eliminate these short duration power quality problems. Incorporated in this system is a communications interface which allows remote access over the telephone network using RS-232 protocol. The system is designed for standalone function without an operator present; however, because of the limited experience of utilities in the use of this type of battery energy storage system, capabilities have been incorporated to allow for datalogging and remote system control of the unit. This paper reviews power quality problems, outlines the system design philosophy from AC Battery Corporation, discusses the rationale for remote telemetering system design, and reviews the utility of this telemetry through the experience of a system installed in Georgia.

      Seeds, Michael A.; Franklin and Marshall College (International Foundation for Telemetering, 1997-10)
      Astronomers now communicate over Internet with robotic astronomical telescopes using a specially designed instruction set. ATIS, Automatic Telescope Instruction Set, is designed to communicate specific, technical instructions to a robotic telescope, facilitate data retrieval and analysis, support a wide range of data formats, and also convey preference information that describe the astronomers general needs for data acquisition. Over a dozen telescopes now use ATIS and more are under construction.

      Ghrayeb, Ali A.; New Mexico State University (International Foundation for Telemetering, 1997-10)
      Sandia National Laboratories (SNL) currently achieves a bandwidth efficiency (h ) of 0.5 to 1.0 bps/Hz by using traditional modulation schemes, such as, BPSK and QFSK. SNL has an interest in increasing the present bandwidth efficiency by a factor of 4 or higher with the same allocated bandwidth (about 10 MHz). Simulations have shown that 32- QAM trellis-coded modulation (TCM) gives a good bit error rate (BER) performance, and meets the requirements as far as the bandwidth efficiency is concerned. Critical to achieving this is that the receiver be able to achieve timing synchronization. This paper examines a particular timing recovery algorithm for all-digital receivers. Timing synchronization in a digital receiver can be achieved in different ways. One way of achieving this is by interpolating the original sampled sequence to produce another sampled sequence synchronized to the symbol rate or a multiple of the symbol rate. An adaptive sampling conversion algorithm which performs this function was developed by Floyd Gardner in 1993. In the present work, his algorithm was applied to two different modulation schemes, BPSK and 4-ary PAM. The two schemes were simulated in the presence of AWGN and ISI along with Gardner’s algorithm for timing recovery, and a fractionally spaced equalizer (T/2 FSE) for equalization. Simulations show that the algorithm gives good BER performance for BPSK in all the situations, and at different sampling frequencies, but unfortunately poor performance for the 4-ary PAM scheme. This indicates that Gardner’s algorithm for sampling conversion is not suitable for multi-level signaling schemes.

      Jones, Charles H.; Gardner, Lee S.; Edwards Air Force Base (International Foundation for Telemetering, 1997-10)
      How difficult is it to develop a pulse code modulation (PCM) stream data format? Specifically, given a size, in bits, and a set of parameter sample rates, how hard is it to find a mapping of the sample rates that fits into the frame size -- if one even exists? Using telemetry trees this paper will show that the number of possible mappings for a given set of parameters and sample rates grows exponentially in terms of the number of parameters. The problem can thus be stated in terms of finding a specific instance, or showing that no such instance exists, among an exponentially large number of potential mappings. Although not proof, this provides strong evidence that the PCM format design problem is NP-complete (meaning it is a member of nondeterministic polynomial space but not a member of deterministic polynomial space). That is, that the problem can not be solved in polynomial time and would take a computer years or centuries to solve relatively small instances of the problem. However, if the problem requirements are relaxed slightly, telemetry trees can be used to reduce the PCM formatting problem to linear time in terms of the number of parameters. This paper describes a technique that can provide an optimal and fully packed PCM format.

      Lautzenhiser, Lloyd L.; Emhiser Research, Inc. (International Foundation for Telemetering, 1997-10)
      A 10- or 20-Watt, L- or S-band transmitter commonly consumes the majority of the available DC power on a telemetry pack -- often more than all the remaining components combined. A new family of transistors allows a substantial increase in DC to RF efficiency without the use of complex and costly switching regulators. With ever increasing data rates requiring more RF bandwidth (and correspondingly lower receiver sensitivities), transmitters using these transistors offer twice the RF power at little or no increase in DC current. Alternately, in other situations such as observation balloons, the same RF power can be achieved with approximately 40% less current resulting in significantly longer mission life. This paper describes the method for achieving higher efficiency transmitters using new LDMOSFETs.

      Pereira, Carlos M.; U.S. Army Armament Research; New Jersey Institute of Technology (International Foundation for Telemetering, 1997-10)
      This paper presents the development of a very high shock telemetry system designed to operate when subjected to acceleration forces of 50,000 g’s in a 120mm gun environment. This system consists of an RF transmitter, a ten channel FM/FM multiplexer, a very rugged power supply, a microstrip patch antenna, and a sensor module. The sensor module contains a tri-axial accelerometer designed to measure the projectile’s low in-flight radial and drag forces and two additional accelerometers to measure the projectile’s high in-bore setback and balloting forces. The sensor suite is located at the center of gravity of the projectile. The patch antenna is incorporated into a radiating structure consisting of a cylindrical metal tube and a plastic cover. To accommodate the antenna in the space available, a microstrip antenna is built on a substrate material that has a dielectric constant of e = 10. Though the cylindrical metal tube, in which the antenna is housed, acts as a cylindrical waveguide operating below its cut-off frequency, its relatively short length allows for adequate power to be radiated for proper system operation. The telemetry system uses standard off-the-shelf telemetry components that were modified and repackaged to withstand the 50,000 "g" environment. All components performed very well in preliminary high "g" (50,000 g’s) tests in a laboratory gun at the Army Research Development and Engineering Center (ARDEC).
    • Mission Integrated Decommutation and Analysis System (MIDAS): Extracting Data from Digital Tape Recordings on a PC

      Thornberry, Lewis; Lake, Phyllis; Lawrence, Ben-z; Eglin Air Force Base (International Foundation for Telemetering, 1997-10)
      This paper presents the Mission Integrated Decommutation and Analysis System (MIDAS), a multi-threaded, multi-processing application developed in Microsoft Visual C++ for Windows NT by the Air Force Development Test Center (AFDTC) Eglin AFB, Florida. The primary function of MIDAS is to support post-test processing of instrumentation data by decommutating, logging, and reporting MIL-STD-1553B or pulse code modulated (PCM) encoded data extracted from MARS-II digital tape recordings. MIDAS processes multiple data streams from a single recording, and can process multiple recordings in parallel. MIDAS also serves as a diagnostics tool for investigating data processing anomalies reported during normal production runs. MIDAS is part of an integrated suite of applications developed to provide AFDTC development test and operational test customers with quickly delivered, high-quality data products. Software development is underway to support the processing of Digital Data Acquisition and On-Board Recording Standard (DDAS) packetized telemetry data. DDAS is derived from the Consultative Committee for Space Data Systems (CCSDS) standard. [MARS-II is the digital acquisition and recording system supported by MIDAS. MARS-II was developed by DATATAPE, Incorporated, Pasadena, California. It records up to 20 gigabytes of mission data across as many as eight channels of MIL-STD-1553B or PCM encoded data. Digital recording technology provides an alternative to traditional analogbased telemetry ground systems.]
    • GPS Receiver Testing on the Supersonic Naval Ordnance Research Track (SNORT)

      Meyer, Steven J.; Naval Air Warfare Center Weapons Division (International Foundation for Telemetering, 1997-10)
      There is an interest in using Global Positioning System (GPS) receivers to find: Time Space Position Information (TSPI), miss distances between a missile and target, and using the data real time as an independent tracking aid for range safety. Ashtech, Inc. has several standalone GPS receivers they believe can work at high g levels. This paper investigates how the Ashtech GPS receivers work under high g loading in one axis. The telemetry system used to collect data from the receivers and the reconstruction of the data will also be discussed. The test was done at SNORT (Supersonic Naval Ordnance Research Track) located at NAWS, China Lake, CA. The g level obtained was about +23 g’s with a deceleration of -15 g’s. The velocity reached was about Mach 2.0. A summary of the errors is included.

      Lettiere, Christopher; Raimondo, Nat; Eglin Air Force Base; TASC (International Foundation for Telemetering, 1997-10)
      The U.S. Air Force has developed GPS-based instrumentation systems to support both test and training activities. In support of recent large-scale exercises, interfaces were developed to employ existing test and training assets in a synthetic battlefield. The writers propose exploration of similar approaches to overcome the challenge of developing a common approach to test and training instrumentation.