RSS 1.0International Telemetering Conference Proceedings, Volume 25 (1989)
ABOUT THE COLLECTION
The International Telemetering Conference/USA (ITC/USA) is dedicated to the promotion and stimulation of technical growth in telemetering and its allied arts and sciences. It is the premier annual forum and technical exhibition providing telemetry specific short courses, technical papers from professionals and students, and exhibits of the industry’s leading companies. ITC/USA is sponsored by the International Foundation for Telemetering (IFT), a non-profit corporation dedicated to serving the technical and professional interests of the telemetering community.
This collection contains the proceedings of the twenty-fifth International Telemetering Conference, October 30-November 02, 1989. The conference, sponsored by the International Foundation for Telemetering, was held at the Town & Country Hotel & Convention Center in San Diego, California.
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International Telemetering Conference Proceedings, Volume 25 (1989)International Foundation for Telemetering, 1989-11
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AIRBORNE TELEMETRY TRENDS FOR THE 1990’sTelemetry hardware technology and application requirements have undergone significant changes in the last 25 years. The trends have produced flight hardware which has had increasingly higher performance, flexibility, reliability and power efficiency while achieving smaller size and weight. This paper will review the evolution and attempt to forecast the direction and trends for future requirements and solutions through the 1990’s.
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Digitized Doppler Signal ProcessorAt the present time there is a requirement for developing an airborne approach for processing radar doppler video data into digital PCM format compatible with current IRIG standards. Techniques for digitizing the doppler video presently exist, but have limitations due to the fact that the data is processed and represented in the time domain. These limitations can be mainly attributed to the high bit rates required for quantizing the dynamic nature of the doppler signal. Therefore, an alternate approach was selected by which the video doppler data is converted and represented in the frequency domain. The time to frequency domain conversion is accomplished with a digital Part Fourier Transform (FFT) implemented in conjunction with a quadrature translator. This method will provide a means by which the doppler signal can be represented as a quasi-static spectrum. The advantage in this application is that only the spectral data which contains relevant engineering information will be processed. The resultant system will thereby minimize the transmission bit rate and maximize the dynamic range for the purpose of signal analysis. The paper will describe the implementation and work performed on the digitized doppler signal processor along with the potential application in PCM systems requiring spectral signal analysis.
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Hardware Implementation of a Digital Anti-aliasing FilterThis paper presents a practical application of a realtime, in-flight programmable digital filter. This filter consists of one module in a PCM system consisting of a central unit and one or more remotes. The paper will also discuss how filtering is achieved given that the PCM format is also user programmable.
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DATA DISTRIBUTION In The TELEMETRY GROUND STATION OF THE 1990’sFor as long as telemetry has been used in scientific research, users have asked for transmission of more data points at higher data frequencies. Now, the increased complexity of vehicles under test and the presence of data from one or several computer systems on a vehicle has further increased the rate and format complexity of a typical telemetry data stream. To accommodate higher data rates and increased complexity, many telemetry ground stations use distributed processing techniques, typically employing a hardware preprocessor, a host computer, and one or more intelligent display stations. While this distribution of power potentially enhances data throughput rates, it imposes new demands on data distribution networks within the processing area, and the full potential of the processors cannot be met until these demands have been met. This paper looks first at system architecture of the typical ground station, and how this architecture and telemetry data rate capability have progressed during the past 20 years. Then it looks at the data distribution requirement in a modern telemetry ground station, explores possible solutions to improve throughput rates, and describes a set of solutions for typical system applications in the next few years.
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The Choices of The Remote-Control Commanding Code Set of The Pseudo RandomIn this paper, it is described that all of these pseudo-random sequences with BaumertWang-Welch’s tow limits can be used to construct remote-control commanding codes; some general conclusions are got, a general formula of maximum fault tolerant number of this kind of code set is given. It is proved that the code set of command, which all of this equivalent translating sequences of a pseudorandom sequence with Baumert-WangWelch’s low limit construct, is an optimal “Cyclic” code set oil interference-free performance. In particular, these equivalent translating sequences of a sequence with period p = 3 mod4, auto-correlation limit & = -1, construct an optimal code set. It’s given that the full essential condition of which a sequence and its inverse sequence together with their equivalent translating sequences can be used to construct remote-control command code set is that the peak value of the absolute values of out of phase periodic autocorrelation of the sequence is little. It is pointed that this constructing way makes coding more effective, easy to carry out, and there are many suitable sequences that can be broadly seleted. In the cases where a high level of interference-free function is required in a remote control system, we usually enforce the commanding into interference-free coding, so that it will posses certain fault-tolerance. The coding and decoding circuits should be simple in equipment and easy to realise. But the efficiency of coding may be quite low. According to the requirements and characteristics, the principles of using the equivalent translating squences m as the remote-control commanding code set, its realization and characteristics are described [1] [2]. A scheme of realising the remote-control commanding by using the sequence m and its inverse-sequence is given [6]. In this paper from the more general point of view, the possibility and the general result of all the pseudo-random sequence reached Baument-Wang-Welch’s inferior limit that is used in remote control commanding code is discussed. The Condition which one sequence and the equivalent translating sequence of its inverse sequence can be used together as the command-code set is given.
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FRAME SYNCHRONIZATION IN DIGITAL BURST TELECOMMAND AT LOW SIGNAL TO NOISE RATIOFrame synchronization was extensively studied usually supposing that the bit pattern to acquire frame synchronization was imbeded in sequences of random bits. In this paper, the determination of a bit pattern for frame synchronization in digital burst telecommand at low signal to noise ratio is investigated, considering the a priori knowledgement of a bit pattern for bit synchronization and the format of the frame. The a priori knowledgement of a bit pattern for bit synchronization is used to find a bit sequence that minimize the false probability to acquire frame synchronization. A simple strategy using the aperture technique is stablished. An egineering model is used to find experimentally the mean probability of true synchronization after one burst. This initial research to find a bit pattern for frame synchronization presented good results.
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Head-mounted Impact Acceleration Measurement SystemThe system measures impact accelerations imparted to a boxer’s head during a boxing bout. The system is comprised of three major subsystems: 1) The acceleration data transmitter located on the boxer’s body. 2) The receiving and storage subsystem. 3) The data processing subsystem. The transmitting subsystem includes a special skull cap fitted with an array of nine accelerometers. The accelerometers are connected to a Abody pack@ located on the boxer’s waist. The body pack houses signal conditioning amplifiers and nine channels of FM/FM modulation divided into one four channel and one five channel multiplexed transmitters. The data transmitted from the boxer is received at the ringside and demodulated. A special threshold detector then triggers analog-to-digital conversion process when the received acceleration data exceeds a predetermined level. The acceleration data is digitized at the rate of 5,000 samples per second. The digitized data for each blow is stored in the random acces memory and the accumulated data for each round is transferred to hard disk after the round. The data collected during the bout is processed after the bout to determine linear acceleration (x,y, and z coordinates), and angular acceleration (about x,y, and z axis) for each blow. The results are stored on a floppy disk to be available for further analysis. The data acquisition, storage, and processing is done by an IBM-PC/AT compatible computer equipped with two megabytes of memory, two floppy disk drives, a hard disk, and a high speed data acquisition board.
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ROTARY HEAD RECORDERS IN TELEMETRY SYSTEMSAlthough magnetic recording devices employing rotary head technology have been around for many years, specific products were not developed with the bit error performance to satisfy the instrumentation recorder needs of the telemetry community. Only recently have a number of new products and new product development programs materialized which offer positive indications that telemetry systems will soon benefit from the higher data rates and storage capacities. The lack of standards in development of rotary head technology has led to development of a variety of design approaches by various manufacturers and system designers. If this trend continues, the telemetry community will not enjoy the media compatibility which has contributed so much to the success of the IRIG instrumentation recorder. The ability to remove a tape recorded on one vendors recorder and replay the tape on a different ground station containing a second vendors recorder is a capability that should be retained with the advent of the new machines. Two standards have evolved defining tape characteristics and the format of information on tape for instrumentation rotary head recorders. For the instrumentation tape media to be truly transportable between telemetry ground stations, standard signal and data formal interfaces must also be developed.
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ADVANCED ACQUISITION AND ANALYSIS THROUGH THE YEAR 2000For nearly a decade U.S. Army Combat Systems Test Activity (USACSTA) has been using computer based telemetry systems to acquire data in a variety of ground vehicles and weapons systems. Three years ago the Advanced Acquisition and Analysis Through Year 2000 (A -2000) project was initiated with the goals of: providing instrumentation systems 3 able to meet the demands of ever more complex weapon systems, increasing workload capacity with no increase in the number or quality of personnel, and reducing the total test cycle time for the customer. The methods selected to implement these goals were: increased reliance on state-of-the-art computer technology, the use of standards for operating systems, programming languages, networking, and interfaces, the use of expert/knowledge based systems, and integration of all organizational computer resources. This paper will describe the progress which has been made in all of these areas.
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A NOVEL APPROACH FOR TELEMETRY TRANSMISSION OF COMPUTER DATAThe Telemetry Group of the Range Commanders Council has provided suggested standards for transmission of telemetry data. These standards were necessary to promote compatibility of operational equipment at the respective Test and Evaluation ranges. For digital transmission, the applicable standards define the frame and word formats necessary for range compatibility. These standards were developed for acquisition of multiple analog and bi-level signals and provided a relatively straight forward means of developing an aggregate, time-division multiplexed (TDM), serial, data stream which includes the information necessary to reconstruct the signals at the ground station prior to analysis. The Inter-Range Instrumentation Group (IRIG) formats are, by design, periodic and form a matrix of Awords@ which are preassigned to each and every signal being encoded and transmitted. As all the original information is continuous in nature, the encoder must sample each of the channels in their proper sequence and place the sampled data in it’s respecitve time slot. This paper will address some of the buffering techniques used to transmit data in an integrated IRIG format. We will then address an alternate solution to transmitting computer data for ground based analysis and processing, i.e., transmission of data using commercial type modems.
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VERSATILE 1553 MUXBUS INTERFACEThis paper presents a 1553 Muxbus Interface which can acquire data, selectively, from up to 3 redundant busses and process it for different airborne or ground test applications. The Interface is built using up todate electronic technology in order to overcome the problems encountered in 1553 protocol decoding and to insure proper data integrity.
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Third-generation Advances in Thermal Printhead-based Chart RecordersA brief recap of the effect thermal printhead technology has had on the common 8-channel strip chart recorder, followed by a summary of second and third generation products and their envolving capabilities. How these new instruments are being accepted and used by telemetrists and ground station managers who are faced with bigger tasks and shrinking budgets. A study of how today’s telemetry professionals are shaping the 8-channel recorders of tomorrow, and the new capabilities they will bring.
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AN AUTO-CALIBRATION SYSTEM FOR A LONGITUDINAL MAGNETIC RECORDERMultiple channel magnetic tape recording is often used for signal analysis of intelligence and telemetry data. To insure accuracy of the reproduced data, these systems require frequent calibration and alignment. As the number of tracks on these systems has increased, this task has become more time-consuming. Even with a well-trained technician, this task can take several hours at a minimum. To alleviate this problem, we developed a system for performing this calibration automatically. The implementation utilizes a Fast-Fourier-Transform technique to analyze the output of a pre-recorded signal on tape. The desired response, most frequently defined by IRIG Standards, is stored in a look-up table in the machine. The actual response is compared to that desired, and, under micro-processor control, adjustment made in the signal channel until an acceptable response is achieved. A unique photo-resistor technique is used in the signal path to control such parameters as gain and phase. A description of the hardware system will be given, as well as a description of the algorithms utilized for implementation.
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MEETING THE FUTURE NEEDS FOR HIGH DATA RATE DIGITAL RECORDINGIn order to satisfy future instrumentation data recording requirements, the availability of high data rate recorders with long record times is most desirable. Also, assurance of commonality amongst the many users of these data requires that any system designed be compatible across the user data base. Hence, the American National Standards Institute (ANSI) has developed a tape format standard that will assure commonality and exchange of data in an acceptable manner. This standard also establishes data rate recording requirements using a commercially available media in cassette form that will satisfy the operational need. DATATAPE is developing a recorder system that will meet the ANSI requirements of the data format on tape, as well as the data rate and record times implied by the standard. This paper discusses the development of the tape format standard and the design of the system that will fully comply with the standard. Test data will be presented to verify system capabilities. Additionally, DATATAPE’s progress in developing a system that will comply with the similar Department of Defense (DOD) tape format Standard, MIL-STD2179, will be presented, along with a summary of DOD programs that require MIL-STD-2179 compliant recorder systems.
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High Performance Optical Disc for Future Telemetry ApplicationsGe Aerospace is developing three classes of optical disk devices for future telemetry applications. SpaceSTORE is a 10 GByte, dual port, rewritable magnetooptic disk drive. Each port suppports continuous write or read at 150 Mbits per second, with an aggregate data rate of 300 Mb/s per drive. One drive and two controllers will be packaged in a total volume of one cubic foot. Drive and controller modules are configurable in groups which are slaved by Group Controllers to provide single port data rates up to 1800 Mbits per second and capacities up to 1012 bits. Typical applications are Space Station, Polar Orbiting Platforms, Mars Rover, and ground support operations. DuraSTORE is a 5 GByte, rewritable magneto-optic disk drive. It is a single port device and supports continuous write or read at 25 Mbits per second and burst I/O at 50 Mb/s. The drive and SCSI controller will be packaged in a MIL-E-5400 5.6 cubic foot rack mount enclosure. The rewritable double sided (10 GByte total) disks are in cartridges, and are removable. A companion 10 disk mini-jukebox provides 100 GBytes capacity and 10 second access. Typical applications are real time signal capture in RC-135 aircraft and C and 3 image mass storage data bases in van and shelter mobile computer systems. UltraSTORE is a 2.5 terabyte archival disk jukebox. It utilizes double sides disks with 20-25 GByte capacity each. I can be configured with 1-3 drives, each operating at data rates (options) from 25 Mbits per second to 1 Gbits/second. Typical applications are ground telemetry data bases, mass storage libraries, and file servers.
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Trends in Recording Capabilities For The ‘90’s’As sensor bandwidths increase and the amount of information gathered increases, higher capacity storage devices will be required as well as increased capture/transmission/reproduce data rates. Both collection/capture sites (with more sensors and wider bandwidths) and link receive/distribution sites will need to be upgraded to accommodate high transmission rates, provide rate matching for capture/dissemination/processing and provide higher capacity storage. These trends and recorder solutions are forecast as natural evolution of the state-ofthe-art. Extended performance (high data rate/high capacity) tape recorders will be discussed as applicable to satelliteto-ground communication, space platform experimental data gathering, reconnaissance, ASW sonar, radar and data processing systems.
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TELEMETRY DATA STORAGE SYSTEMS TECHNOLOGY FOR THE SPACE STATION FREEDOM ERANASA’S Space Station Freedom and the Earth Observing System, due to be operational in the mid-1990’s, will provide scientists the vehicles to deploy an unprecented number of data producing experiments, including advanced imaging instruments with high spatial and spectral resolution. Peak down-link data rates are expected to be in the 500 megabit per second range, and the daily volume of science data could reach 2.4 terabytes. Such startling requirements have stimulated development efforts in high rate on-board recorders, and inspired an internal NASA study to determine if economically viable data storage solutions are likely to be available to support the ground data transport segment. This paper summarizes the mission and system drivers for telemetry data recording and storage capabilities, and provides an overview of NASA efforts to prototype advanced storage systems.
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Research of Diversity Receive for Re-entry Telemetry SystemThis Paper is based on results of radio signal propagation tests that are performed on sea and ground. Other test results also are referred. Practice of polarity diversity. space diversity and frequency diversity used for re-entry telemetry system is discussed briefly. The achieved effect and existing problems in using diversity technology is analyzed. Finally, the diversity technology is evaluated with respect to engineering.
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FROM TRANSDUCER TO DISPLAY IN A WORKSTATION ENVIRONMENT: A REAL TIME DATA ACQUISITION SYSTEMThis paper will address the application of an end-to-end programmable PCM telemetry system featuring a modular, programmable data acquisition and encoding system, and a data analysis work station using an IBM PC compatible computer.
