• RADSCAN A NOVEL CONICALLY SCANNING TRACKING FEED

      Sullivan, Arthur; Electro Magnetic Processes, Inc. (International Foundation for Telemetering, 1982-09)
      This paper presents a description of RADSCAN, a novel conically scanning tracking feed which has only one moving part and utilizes a solid state optical commutator for reference. The feed operates continuously from 1435 to 2400 MHz thereby covering all the existing telemetry bonds in addition to the proposed new bond from 2300 to 2400 MHz. The performance of RADSCAN is compared to that obtainable with the single-channel monopulse technique.
    • RANGE STANDARDS PANEL DISCUSSION

      Ashley, Carl G.; Pacific Missile Test Center (International Foundation for Telemetering, 1982-09)
      The Telemetry Group (TG) of the Range Commanders Council is the primary means of exchanging telemetry technical and operational information and coordinating and standardizing systems, techniques, methods, and procedures. The TG is concerned with such telemetry gathering instrumentation as airborne sensing devices and modulation and multiplexing equipment. In addition, the group monitors developments in telemetry processing and storage systems and special display devices. The group is also responsible for writing and updating the Telemetry Standards Document and a series of five volumes on Text Methods for Telemetry Systems and Subsystems.
    • REAL-TIME DATA DISPLAY FOR AFTI/F-16 FLIGHT TESTING

      Harney, Paul F.; NASA Ames Research Center (International Foundation for Telemetering, 1982-09)
      The overall objective of the advanced fighter technology integration/F-16 (AFTI/F-16) advanced development program is to demonstrate, separately and in combination, advanced fighter technologies to improve air-to-air and air-to-surface weapon delivery and survivability. Real-time monitoring of aircraft operation during flight testing is necessary not only for safety considerations but also for rapid preliminary evaluation of flight test results. The complexity of the AFTI/F-16 aircraft requires an extensive capability to accomplish real-time data goals; this paper describes that capability and the resultant product.
    • RECOVERY OF PCM TELEMETRY DATA IN THE PRESENCE OF INTERFERENCE SIGNALS

      Hahn, Jacob C.; Rockwell International M/S DA-37 (International Foundation for Telemetering, 1982-09)
      PCM data is recorded on magnetic tape on-board the Space Shuttle during flight. After the vehicle has landed these tapes are played back into a laboratory tape recorder and copies or dubs are made. PCM data from the vehicle is also recorded during manufacture and preflight testing and dubs of these tapes are made. Signals from other electronic equipment at the recording site can be picked up and mixed with the PCM data. This can cause dropouts (loss of data) during playback. The low frequencies are easily removed by filtering but higher frequencies that lie in the same range as the data cannot be removed by filtering. Methods for dealing with this problem have been worked out with some success. The work has just started. Some of the results are described here.
    • A REVIEW OF THIRTY YEAR’S DEVELOPMENTS AND RESEARCHES ON UNCODED QPPM SYSTEMS

      Chang, Jiang; Yingcai, Chen; Beijing Research Institute of Telemetry; Engineering Chinese Academy of Space Technology (International Foundation for Telemetering, 1982-09)
      In recent years the researches and applications of QPPM systems in telemetry have drawn much attention, but there are still some problems to be clearified and solved. In this paper we reviewed the classical literatures on un-coded QPPM systems which were published in the past thirty years. After analysing the conclusions and related derivation presented in these publications, we got: 1) M.J.F, Golay and JRA Jacobs stated that the QPPM’s efficiency ß may indefinetely approach Shannon theoretical limit with as small error probability as desired as soon as one can appropriately choose the parameters of the system. In our opinion, this conclusion cannot hold true. In fact, the efficiency curve ß = F(α) of QPPM is only similar in form to the Shannon theoretical limit and there is still a large difference. 2) In past 30 years Golay and the others analysed merely the relation between the word error probability PWE and the efficiency ß , They didn’t study the relation between the bit error probability PBE and ß . Some authors regarded QPPM’s PWE as being equal to other digital system’s PBE, and concluded that QPPM is better than the other systems. We consider that this is not appropriate. 3) In order to remedy the untouched problem, we derived the relation PBE =F(α) of QPPM system. As it is seen from these relation curves that the required α of QPPM is 4.CdB~4.4dB more than the ß of coherent detection PSK system when PBE=10^-4 and α varries from 2 to 100. (ie. the efficiency of QPPM is worse than PSK.)
    • S-BAND ACQUISITION AND TRACKING SYSTEM (SATS), WSMR SYSTEM FOR SPACE SHUTTLE ACQUISITION

      Blazosky, David M.; Kroeger, O. Paul; US Army White Sands Missile Range (International Foundation for Telemetering, 1982-09)
      The requirement for WSMR to independently acquire and track the NASA Space Shuttle presented WSMR with one of the basic problems associated with missile and air defense systems - acquiring and maintaining a precision track of an incoming target. The popular solution is to use two radars--a broad beam for acquisition and a narrow beam for precision track. The WSMR solution is the S-Band Acquisition and Tracking System (SATS) which uses two existing passive telemetry trackers (J-10 and J-67) in conjunction with WSMR precision track radars. The existence of an S-Band transmitter in the Shuttle made the use of the Telemetry trackers possible.
    • SATELLITE DATA LINK STANDARDS*

      Lt. Gibson, Col. R.H.; Maj. Sutton, R.V.; Rodriguez, T.M.; Tamura, Y.; Air Force Systems Command; The Aerospace Corporation (International Foundation for Telemetering, 1982-09)
      Flexibility and survivability of Space Communications dictate the interoperability of communication links between as many satellites as feasible. Interoperability increases survivability by providing alternate paths. Interoperability also improves total system reliability and cost effectiveness, and it permits a flexible, distributed communications architecture to evolve. To implement this approach, functional satellite data link standards are needed to pull together mission data relay, communications, and tracking, telemetry and command (TT&C) requirements so that they can be satisfied by a common link design. The basic requirement which unifies these diverse users is their need for uplink jamming protection and scintillation resistance (in a perturbed atmosphere) at low (75 bps to 19.2Kbps) data rates. While the downlink and crosslink requirements are more diverse, they do not constitute major drivers of the standard. This paper describes Space Division’s standardization effort, the links to be standardized, the parameters that must be defined and an evolutionary implementation approach. The first satellite-ground links to be standardized will use 44/20 GHz with wideband spreading for jam resistance, while the crosslinks will use 60 GHz to avoid terrestrial jamming. Key issues are discussed, such as the conflicting requirements between TT&C and communications and the tradeoffs between minimum designs and flexibility.
    • SEMICONDUCTOR OPTOELECTRONIC DEVICES FOR FREE SPACE OPTICAL COMMUNICATIONS

      Katz, Joseph; Jet Propulsion Laboratory (International Foundation for Telemetering, 1982-09)
      Light emitting devices based on AlGaAs lasers are very useful radiation sources in free space optical communications systems. After a brief review of the properties of individual injection lasers, more complex devices are described. These include, or are relevant to, monolithic integration configurations of the lasers with their electronic driving circuitry, power combining methods of semiconductor lasers, and electronic methods of steering the radiation patterns of semiconductor lasers and laser arrays. Fabrication of such devices is one of the major prerequisites for realizing the full potential advantages of free space optical communications.
    • SHOCK-HARDENED, HIGH FREQUENCY, PCM SYSTEM WITH MEMORY FOR EARTH PENETRATOR STUDY APPLICATIONS

      Barnes, David E.; Sandia National Laboratories (International Foundation for Telemetering, 1982-09)
      Increasing data requirements for earth penetrating vehicles have necessitated the design of a new digital telemetry system with greater signal frequency response, higher resolution, and more memory capacity than used previously. The new system encodes data into 8 bit digital words at a rate of 3.2 megabits per second and stores the data into a 640 Kbit CMOS memory for readout after the recovery of the penetrating vehicle. This paper describes the penetrator program and the new telemetry system developed for it.
    • SINGLE CHANNEL PROTOCOL FOR TELEMETRY SETUP AND CONTROL

      Hahn, Karl; Sangamo Weston, Schlumberger (International Foundation for Telemetering, 1982-09)
      In any telemetry data system whose functions are distributed over a number of physical units, it is desirable, if not necessary that these units be woven into a unified control network. It is this control network that makes a telemetry system out of the separate units. It turns out that this problem can be solved inexpensively, allowing new telemetry units to be easily added to the system, and without impacting the data flow between units. This paper describes one such solution, and details its flexibility and power. Some topics covered are central control, device independence, and relationships between user stations and physical units.
    • SOFTWARE PROCESSING FOR THE REAL TIME DATA ACQUISITION SYSTEM (RDAPS)

      Tucher, Tommy N.; Hutchinson, Michael P.; Edwards Air Force Base; Sangamo Weston, Inc. (International Foundation for Telemetering, 1982-09)
    • SOFTWARE SUPPORT FOR A STORED PROGRAM PCM DECOMMUTATOR

      Peterson, Dwight M.; Fleet Analysis Center (International Foundation for Telemetering, 1982-09)
      Telemetered data generated by missile systems has become increasingly complex with the inclusion of asynchronous data streams, variable word lengths, and discrete encoding. The display of this data for analysis purposes requires sophisticated equipment, usually designed with a programmable architecture. This paper describes software support that was developed for a stored program PCM decommutator. The software includes a cross assembler and supports downline loading of the decommutator from a host computer.
    • SPACE SHUTTLE COMMUNICATIONS AND TELEMETRYAN INTRODUCTION WITH FLIGHT RESULTS

      Hoagland, J.C.; Rockwell International (International Foundation for Telemetering, 1982-09)
      During operational space flight, the communications and telemetry subsystem of the Space Shuttle orbiter uses S-band and Ku-band links to provide, in addition to tracking, reception of digitized-voice, commands, and printed or diagrammatic data at a maximum rate of 216 kilobits per second (kbps). The subsystem also provides a transmission capability for digitized voice, telemetry, television, and data at a maximum rate of 50 megabits per second (mbps). S-band links may be established directly with a ground station and both S-band and Ku-band links may be routed through The National Aeronautics and Space Administration (NASA) tracking and data relay satellite system (TDRSS). 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. Ultra-high frequency (UHF) is used for communication with extravehicular astronauts as well as for a backup subsystem for state vector update. Audio and television subsystems serve on-board needs as well as interfacing with the radio frequency (RF) equipment. During aerodynamic flight following entry, the S-band link can be supplemented or replaced by a UHF link that provides two-way simplex voice communication with air traffic control facilities.
    • THE SPACE SHUTTLE ORBITER’S KU-BAND RADAR SUBSYSTEM

      Shingledecker, D. K.; Hughes Aircraft Company (International Foundation for Telemetering, 1982-09)
      The Space Shuttle Orbiter’s Ku-band integrated radar and communications subsystem will function in its radar role during satellite rendezvous. As a radar the Ku-band subsystem searches for, acquires, and then tracks targets. In the track mode, the radar outputs measured range, range-rate, angle, and angle-rate values to both the Orbiter’s general purpose computer (GPC) and the astronaut’s Ku-band subsystem control panel. This data is used to navigate the Orbiter to its satellite rendezvous. The radar is integrated with the Ku-band communications function and thus achieves reduction in weight and volume compared with separate subsystems for each function. This paper provides a user oriented description of the radar subsystem. Topics to be covered are radar requirements, modes of operation, and system configuration.
    • SPACE SHUTTLE PAYLOAD INTERROGATOR

      Zelon, Michael; Space Transportation & Systems Group Rockwell International (International Foundation for Telemetering, 1982-09)
      The payload interrogator (PI) for communication between the orbiter and detached DOD/NASA payloads is described. Salient features of the PI are discussed, including its capabilities and limitations. For compatible operation in the orbiter’s electromagnetic environment, the PI is equipped with a dual triplexer assembly. A limiter diode circuitry allows the PI to be safely exposed to high effective isotropic radiated power (EIRP) payloads at close range. A dual conversion PM short-loop receiver has a sufficient dynamic range for undistorted reception of near and distant payload signals. The PI acquires signals from compatible transponders within ±112 kHz of its center frequency. The center frequency can be set at 125-kHz steps for the spaceflight tracking and data network (STDN), 370 kHz for the deep space network (DSN), and 5 MHz for the space satellite control facility (SCF). The PI has falselock- on protection capability to accommodate reliable acquisition of standard NASA and DOD payload transponders. The wideband phase detector demodulates baseband information, and by the use of AGC, provides three independent constant-level data outputs. Each of the 861 frequency channels is generated instantaneously by the receiver and transmitter synthesizers. The PM-modulated RF carrier transfers command information to the detached payloads. The RF output power is adjustable to assure reliable communication with payloads of various sensitivities (G/T). A wide and narrow carrier sweep capability is provided to accommodate any frequency uncertainty of payloads. The transmitter has an ON-OFF modulation control to avoid false-lock-on problems. The PSP command input modulation index is fixed, while the modulation index for the PS is a function of the input voltage. The PI receiver’s complementary transmit channels are spaced 115 kHz for STDN, 341 kHz for DSN, and 4 MHz for SCF. The PI is compatible with the orbiter’s configuration control equipment—GCIL, the PSP and PS for I/O data transfer, the Ku-band subsystem for “bent pipe” baseband telemetry transmission to ground, the MDM for the PI’s telemetry transfer, and the RHCP/LHCP antenna subsystem. Overall PI capabilities and limitations for communication with unique payloads are also presented.
    • SPECTRAL SHAPE PREDICTOR FOR PCM/FM TRANSMISSIONS

      Brown, Roger W.; McDonnell Douglas Astronautics Company (International Foundation for Telemetering, 1982-09)
      This paper will demonstrate a computer application program to predict the spectral shape and IRIG-RF bandwidth required for a PCM/FM telemetry system. A filtered PCM bit stream is constructed from a Fourier series and used to FM-modulate the RF carrier. The Fourier transform of the FM-wave is calculated numerically, and voltage amplitude levels are plotted on a Tektronix graphic display. Several PCM bit patterns are used and a composite display is formed to approximate an actual PCM/FM spectrum. A comparison of predicted and actual spectra will be presented.
    • A STATISTICAL MODEL OF THE PHOTOMULTIPLIER GAIN PROCESS WITH APPLICATIONS TO OPTICAL PULSE DETECTION

      Tan, Harry H.; University of California (International Foundation for Telemetering, 1982-09)
      The complete statistical behavior of the random gain of a photomultiplier tube (PMT) has not previously yielded to exact analysis. In this paper a Markov diffusion model is used to determine an approximate probability density for the random gain. This approximate density preserves the correct second order statistics and appears to be in reasonably good agreement with previously reported experimental data. The error performance of a simple binary direct detection optical communication system is analyzed using this density.
    • SYSTEM DESIGN METHODOLOGIES

      Kelly, Mike; Sangamo Weston, Schlumberger (International Foundation for Telemetering, 1982-09)
      This purpose of this paper is to show how structured programming methodologies, used in the design and development of computer programs, can and should be used in the design and development of telemetry systems. One important concept presented in that of thinking of the telemetry system as a complete system from the very beginning such that a total system design can evolve “naturally”. Many of the problems associated with telemetry systems today are due to the fact that the various “pieces” of the system were designed independently and without regard for each other. Also discussed are the various levels of documentation produced along with Engineering and Marketing responsibilities as they relate to systems design.
    • TACTICAL INFORMATION EXCHANGE

      Kroger, Marlin G.; Palos Verdes Estates (International Foundation for Telemetering, 1982-09)
      This paper addresses the development of an architecture or framework to guide the design of future communications links and networks to support tactical military operations. In the next decade military forces are planned to be much more mobile and dispersed than they are today. Improved sensors and information processing capabilities will provide information needed to manage defense actions against numerically superior enemy forces, but the effective use of that information will require greatly improved communications capability. The resultant digital information traffic which consists of bursts of data between and among users and data sources must be accomodated efficiently, something that neither the present circuit-switches nor the current store-and-forward message transmission systems do well. Also, there is a requirement for much more interoperability between the systems of different services and nations. Internetwork routing of data transmissions can provide more robust connectivity via alternate paths, to cope with jamming and physical attacks on specific transmission media or nodes. An approach to data network interconnection structure that has emerged over the past several years is the concept of a hierarchial set of protocol layers, each one building on the one below. In total, they constitute a reference model for “open systems interconnection.” The most common version of such a reference model is the International Organization for Standardization’s reference model of Open Systems Interconnection (ISO OSI) (1). The ISO OSI model has been designed to serve the fixed plant, benign-environment commercial user. DoD has special needs for security, precedence, internetwork data transfer and user mobility that are not yet reflected in the ISO model. Because of these special needs candidate DoD models that are different from the ISO model have been proposed. However, an important consideration in the choice of or development of a DoD standard is that DoD Systems should be able to use commercial equipment and interface with commercial data networks. Also a consideration is that the reference model used for strategic and tactical communications should be a standard throughout DoD, although specific protocols could differ as necessary to support tactical vs. strategic needs. In total, these requirements and considerations constitute a significant design challenge that must be addressed promptly if DoD is to have any influence on the finalization of the ISO OSI model to get it to accomodate DoD requirements as much as possible.
    • THE TAPE RECORDER SHUTDOWN ALARM

      Hahn, Jacob C.; Rockwell International (International Foundation for Telemetering, 1982-09)
      Data from the Space Shuttle is recorded on magnetic tape during manufacture, during pre-flight tests and during flight. Thus a permanent record is obtained for all tests. When a tape recorder suddenly stops before the end of its run, some data will not be recorded. Tape recorders run silently and make no sound when they stop. A tape recorder that is not running is easily observed, but constant visual monitoring is impractical. Yet it is important that personnel become aware of the problem at once. An audio alarm that sounds when a tape recorder stops before the end of its run will alert personnel. An alarm in use at Rockwell’s Flight Systems Laboratories not only sounds when a tape recorder stops before it is supposed to, but it turns on a standby recorder in less than two seconds.