• The Space Shuttle Orbiter Communication and Tracking System

      Carrier, Louis M.; Pope, Warren S.; Rockwell International (International Foundation for Telemetering, 1978-11)
      During space flight, the communications and tracking system of the Space Shuttle orbiter uses S- and Ku-band links to provide tracking; reception of digitized voice, commands, and printed or diagramatic data at a maximum rate of 216 kilobits a second; and transmission of digitized voice, telemetry, television, and data at a maximum rate of 50 megabits a second. S-band links may be established directly with a ground station and both S- and Ku-band links may be routed through NASA's Tracking and Data Relay Satellite System A simultaneous capability to communicate with other satellites or spacecraft, using a variety of formats and modulation techniques on more than 850 S-band channels, is provided. UHF is used for communication with extravehicular astronauts. Audio and television subsystems serve on-board needs as well as interfacing with the RF equipment. During aerodynamic flight following entry, a UHF link provides two-way simplex voice communication with Air Traffic Control facilities. Air navigation aids include TACAN, a microwave scan-beam landing system and radar altimeters.
    • Data Asymmetry Analysis for Space Shuttle Communications Link

      Simon, M. K.; Tu, K.; Batson, B. H.; Jet Propulsion Lab; Lockheed Electronics Company; NASA Lyndon B. Johnson Space Center (International Foundation for Telemetering, 1978-11)
      This paper systematically analyzes the signal-to-noise ratio degradations which can potentially occur due to data asymmetry in digital transmission systems. Suitable asymmetry models are developed and error probability performance for two types of data detectors (integrate-and-dump filter, and gated-integrate-and-dump filter) is derived. Although this work was done to resolve problems being encountered in the Shuttle Kuband return link design, specifically for the 50 Mbps convolutionally encoded channel (NRZ format), generalizations are made which provide results for other cases of interest (other Ku-band return link channels, or other systems entirely). This paper therefore considers Manchester data formats (in addition to NRZ) and uncoded transmission (in addition to convolutionally coded transmission).
    • Source Coding and Speech Compression

      Gray, R. M.; Buzo, A.; Matsuyoma, Y.; Gray, A. H., Jr.; Markel, J. D.; Stanford University; Signal Technology, Inc. (International Foundation for Telemetering, 1978-11)
      An overview of recent applications of source coding theory and techniques to Linear Predictive Coded Coded speech compression systems is presented. Several distortion measures proposed for use in speech compression systems are described and compared. These distortion measures are then combined with an algorithm for computing "optimum" (minimum distortion) vector quantizers to obtain optimum quantizers for reflection coefficient vectors in Linear Predictive Coded speech systems. The quality of the system is evaluated via the speech distortion measures and listening to demonstration tapes. Some implications for speech compression theory and practice are discussed.
    • Packet Telemetry: A Possible Standard Protocol for Spacecraft Data Handling

      Greenberg, Edward; Hooke, Adrian J.; NASA Jet Propulsion Laboratory (International Foundation for Telemetering, 1978-11)
      Packetized telemetry-handling offers an opportunity to standardize major portions of the spacecraft-to-ground interface for future NASA missions. An end-to-end packet transport protocol is proposed which enables delivery of telemetry data from a remote space sensor to a ground-based user with virtually no project-unique intermediate processing. This paper reviews the possibility of creating a single telemetry format standard for both deep-space and near-earth missions. The proposed standard addresses the greatest NASA problem of the coming decade - cost - by allowing telemetry streams from many inflight spacecraft to be handled on the ground by common, simple, multimission processing elements.
    • Signal Processing with Saw Devices

      Milstein, L. B.; Arsenault, D. R.; Das, P. K.; UCSD; Rensselaer Polytechnic Institute (International Foundation for Telemetering, 1978-11)
      The use of surface acoustic wave devices to perform real time Fourier transformation for time-limited signals is well known. In this paper a detailed analysis justifying the implementation most typically employed will be presented, as well as the description of a scheme which extends the above technique by allowing the transformation of a long sequence of contiguous random data. This latter situation, of course, is that normally encountered in a digital communication system.
    • The LES-8/9 Telemetry System: Pt I, Flight System Design and Performance

      Sarles, F. W.; Helfrich, J. H.; McKenzie, P. F.; Roberge, J. K.; Massachusetts Institute of Technology (International Foundation for Telemetering, 1978-11)
      LES-8 and LES-9 are two experimental communication satellites designed and built for the Air Force by the M.I.T. Lincoln Laboratory. The on-board telemetry systems were designed not only to monitor the spacecraft on orbit but also to provide significant test support capability during subsystem development and spacecraft integration and test. Each system is configured in a distributed form, with remote Telemetry Input Converters (TICs) located in various subsystems communicating with a central Telemetry Output and Control (TOC). Salient features include 1) modular design of TICs permitting tailoring to specific subsystem requirements, 2) accurate analog measurement capability (.025% of full scale) over 140EC ambient temperature (-60°C to +80°C), 3) cross-checking of analog-to-digital converters via a high stability (50 microvolts) stepped calibration source, 4) flexible word allocation permitting late freezing of formats, 5) digital organization with individual parity check on each word, 6) sub multiplexing capability, 7) dual speed operation at 100 bps and 10-Kbps, and 8) downlink capability via a variety of rf links. Descriptions of overall operation and performance along with design considerations in critical areas are covered in detail.
    • A Simulator for the SEASAT-A Synthetic Aperture Radar Ground Support Network

      Jones, S. C.; Colson, J. D.; Grunberger, P. J.; John Hopkins University (International Foundation for Telemetering, 1978-11)
      The characteristics and capabilities of link measurement and simulation equipment for the NASA ground stations supporting the SEASAT-A synthetic aperture radar (SAR) are described. The Spaceflight Tracking and Data Network (STDN) SEASAT-A SAR Simulator generates SAR radar and data link signals, including chirp, radar return, pilot, PRN radar timing, and noise components. After injection into and passage through the STDN SAR equipment, the simulated SAR signals are processed in real time to determine ground support equipment readiness and performance. The equipment has been used to verify the performance of SAR unique support equipment prior to site delivery and during integration testing at NASA, European Space Agency (ESA), and Canada Centre for Remote Sensing (CCRS) ground support stations. It has also been used to test SAR flight equipment. It is currently being used for site prepass readiness testing.
    • Shallow Bulk Acoustic Wave Devices - A New Type of Acoustic Wave Device for Communication Systems

      Lau, K. F.; Yen, K. H.; Kagiwada, R. S.; TRW Defense and Space Systems Group (International Foundation for Telemetering, 1978-11)
      This paper reviews the present status of a new type of acoustic wave device which has many potential applications. These devices are called Shallow Bulk Acoustic Wave (SBAW) devices because the signal propagates just below the surface of the piezoelectric substrate. These waves can be efficiently generated and detected by interdigital transducer and fabricated by techniques similar to those of surface acoustic wave (SAW) devices. These planar devices have been configured into bandpass filters, delay lines, oscillators and resonators. Because they utilize bulk waves rather than surface waves, SBAW devices possess many advantages over SAW devices. They have a higher frequency of operation, lower loss, better temperature stability, and, most likely, better aging characteristics. With these advantages, SBAW devices promise to replace both bulk crystals and SAW devices in many future communication systems.
    • An Efficient Multichannel FFT Demodulator

      von der Embse, U. A.; Austin, M. C.; Hughes Aircraft Company (International Foundation for Telemetering, 1978-11)
      A multichannel binary FSK demodulator for spaceborne application has been implemented using an efficient preweighted and thinned fast Fourier transform (FFT) algorithm. Theory, configuration, and performance are described and compared with the analog unit which performs the same functions. Being able to perform the first base 16 pass with add-only operations following preweighting, provided the complexity reduction which made it feasible to use the FFT to perform the channelization and predetection filtering.
    • Experimental Evaluation of MSK and Offset Keyed QPSK Through Satellite Channels

      Horwood, D. F.; Angello, P. S.; Hughes Aircraft Company (International Foundation for Telemetering, 1978-11)
      Laboratory test measurements show nearly equivalent error rate performance of MSK and OKQPSK modulation formats for channels having bandwidths approximately equal to the bit rate bandwidth and typical associated phase delay characteristics. High quality MSK and OKQPSK transmitters and a versatile modular receiver have been designed and constructed to eliminate differences associated with varying degrees of hardware quality when the performance of the various modulation formats is compared. The selection of a modulation format should, therefore, be strongly directed by considerations other than error rate, such as complexity, sensitivity to alignment, and compatibility with differential coding.
    • Experimental 2 GBPS MM Wave System and 4 GBPS QASK Modulator

      Horwood, D. F.; Luke, R. T.; Lee, G. E.; Des Brisay, G. S., Jr.; Hughes Aircraft Company (International Foundation for Telemetering, 1978-11)
      A 2 GBPS QPSK modulator and demodulator were developed and BER performance was evaluated over a millimeter wave data channel. The error rate measurements taken with the breadboard equipment showed system performance to be less than 2 dB from theoretical at an error rate of 10⁻⁵. Additionally, a second QPSK modulator was constructed and combined with the first to generate 4 GBPS QASK data for future evaluation.
    • Step-By-Step Decoding of Alternant Codes

      Omidyar, C. G.; Helgert, H. J.; The George Washington University (International Foundation for Telemetering, 1978-11)
      In this paper we present a decoding scheme for Alternant codes. The syndromes are calculated from the received vector and the parity check matrix H. Let t be the error correcting capability of the decoder. Then we determine a Key Equation by adding t columns of the parity check matrix H. We raise this equation t-1 times to the power of n, where n is the number of columns of H. Next we consider a matrix At whose elements are the set of coefficients from the Key Equations which we obtained. We make a decision based on the determinant of the matrix A(t). If the matrix A(t) is singular, then we test the matrix A(t-1) for singularity and continue up to A(t-t+1) which in fact the decoder can correct one error. if any one of the matrices A(t) through A(t-t+1) is nonsingular we change the first digit of the received vector, then recompute the syndromes and recheck Δt'. If Δt' is zero the change is retained. If not, the digit is changed again. The Algorithm then proceeds to the next digit. This Algorithm for decoding Alternant codes has significant improvements over previous schemes since the step-by-step decoding can be carried out at selected areas of the received word.
    • Telestream™ - Grumman's Distributed, Parallel Telemetry Processing System

      Gittleman, Michael; McCormick, Raymond; Grumman Data Systems Corp. (International Foundation for Telemetering, 1978-11)
      TeleSTREAM™, the GrummanData Systems Corporation telemetry processor, is a hierarchically arranged combination of hardware, firmware and software which can meet the current and future needs for real time processing of telemetry data. The basic design of the system is highly flexible, allowing application to a wide range of user requirements with a minimum of software changes. The logical flow of input, process, output is accomplished by a distributed processing method utilizing three subsystems: Front End Controllers (FEC's); Task Oriented Processors (TOP's); and Output Processors (OP's). Multiple sources can be processed concurrently, with the FEC's selecting specified data words for processing. Typical telemetry processing tasks are handled by a parallel arrangement of table driven processors (TOP's) utilizing a combination of assembly language and microcoded routines. Output processing routes completed buffers of data to a variety of output devices. Additionally, setup, control, diagnostics and status servicing of telemetry formatting equipment is performed by the OP's. A telemetry compiler allows the user to describe to the system the processing requirements of a particular data source and produces the tables utilized by TeleSTREAM™ to handle the parameters.
    • TIPS Telemetry Compiler

      Billerbeck, G.; Idsardi, R.; System Development Corporation (International Foundation for Telemetering, 1978-11)
      The TIPS Telemetry Compiler is a keyworded-free format language processor used to generate run-time tables for controlling the real-time software and front-end hardware of the Telemetry Integrated Processing System (TIPS) at Vandenberg Air Force Base. The use of a compiler shortens response time to new requirements and improves analyst productivity. The Telemetry Source Language (TSL) is the interface between the telemetry analyst and the compiler. For example, TSL statements are used to specify parameters for the telemetry stream, compression algorithms, data acquisition, display, and history recording. Considerable flexibility has been built into the internal structure of the compiler by the use of an Input Control Definition Language (ICDL) to define the construction of the TSL. The flexibility provided by the use of an ICDL to map the source language into the compiler data base is essential for adapting the compiler to requirements beyond the scope of the original construction. The compiler data base is sufficiently large and complex to require the implementation of data base management and memory management techniques. The nature of these facilities is important for a modular architecture and for reasonable computational efficiency. These key features of the internal structure of the Telemetry Compiler are transparent to the Compiler user. The output of the compiler is a Run-Time File for use by the Real-Time Software in loading the programmable front-end hardware and in software process control. The TIPS Telemetry Compiler is written in structured FORTRAN on a CDC CYBER 173. The real-time software executes on a network of SEL 32/55 processors. At the time of publication, the framework of the compiler was completed as well as major portions of the run-time file generation phase, and the compiler had been used to build run-time files for major development milestones.
    • A Fast Complex Integer Convolution Using a Hybrid Transform

      Reed, I. S.; Truong, T. K.; University of Southern California; California Institute of Technology (International Foundation for Telemetering, 1978-11)
      In this paper it is shown that the cyclic convolution of complex values can be performed by a hybrid transform. This transform is a combination of a Winograd transform, and a fast complex integer transform developed previously by the authors. This new hybrid algorithm requires fewer multiplications than any previously known algorithm.
    • Subcarrier Phase Recovery Performance in Bent-Pipe Mode of Shuttle Data Transmission

      McKenzie, Teresa M.; Braun, W. R.; LinCom Corporation (International Foundation for Telemetering, 1978-11)
      The subcarrier phase recovery is analyzed for the bent-pipe mode of Space Shuttle detached-payload data transmission on the Tracking and Data Relay Satellite System (TDRSS) Ku-band return link. The high-power component of the subcarrier modulation is unrestored payload data, either at baseband or modulating another subcarrier. At the receiver a Costas loop recovers the subcarrier phase. To analyze its performance in the baseband case, we obtain the loop S-curve, the power spectral density of the equivalent noise process, and the loop phase error variance.
    • The GPS Satellite and Payload

      Codik, Andrew; Gronlund, Robert A.; Rockwell International Corporation (International Foundation for Telemetering, 1978-11)
      The NAVSTAR/Global Positioning System Satellite is briefly outlined as is the technique for navigation using signals from such satellites. A description of the GPS navigation subsystem with emphasis on its microprocessor and its interfaces and software routines is given.
    • The Wide-Band Signal Processor

      Stiffler, J. J.; Raytheon Company (International Foundation for Telemetering, 1978-11)
      The Wide-Band Signal Processor (WBSP) is a spaceborne communications processor designed to operate as a peripheral to the Fault-Tolerant Spaceborne Computer (FTSC) currently being developed for the U. S. Air Force. Its function is to demodulate and decode received FDM and TDM signals and to re-encode the recovered information and use it to modulate signals for retransmission. The major difference between the WBSP and other processors designed to perform similar functions is in the fact that the WBSP, like the FTSC itself, is designed to survive its own hardware malfunctions.
    • Applied Telecommunication System [FATEC] Using Microprocessor for Versatile Data Acquisition and Supervisory Control

      Okamoto, Takashi; Atsuya, Kin-ichi; Higeta, Tsukumo; Kakehi, Gen; Iizuka, Masaru (International Foundation for Telemetering, 1978-11)
      It is required recently for data acquisition and supervisory system to provide transparent transmission of bit and message informations by packet or non-packet transmission method, and to provide various kinds of interface to I/O. In order to fulfill these requirements we have developed the new system called FATEC(Fujitsu Applied Telecommunication System) using microprocessor and bus technology.
    • Performance Evaluation for Shuttle/TDRSS Links Using Analytical Simulation

      Lindsey, William C.; Braun, Walter R.; LinCom Corporation (International Foundation for Telemetering, 1978-11)
      An analytical simulation package has been developed by LinCom Corporation for analytical verification of bit error rate and tracking services performance for both S- and K-band Shuttle user service through the Tracking and Data Relay Satellite System (TDRSS). The purpose of this effort was to provide a tool to assess overall system performance as well as the sensitivity to key subsystem parameters and to ensure compatibility of TDRSS and Shuttle transponder performance specifications. The evaluation is based on analytical simulation, i.e., a combination of simulation techniques and analytical performance evaluation. This allows the use of a more realistic signal format than is possible with a purely analytical approach and maintains the advantage of short computation time. The Shuttle forward and return link models and the main features of the simulation are described. Sample results of the computer runs are provided for current power budgets and system design parameters.