Now showing items 1-20 of 59

    • Appendix A: Thirteenth Annual Report of the Telemetering Standards Coordination Committee

      Muller, Ronald M. (International Foundation for Telemetering, 1974-10)
    • 117.6-Kilobit Telemetry from Mercury In-Flight System Analysis

      Evanchuk, V. L.; California Institute of Technology (International Foundation for Telemetering, 1974-10)
      This paper discusses very specifically the mode of the Mariner Venus/ Mercury 1973 (MVM'73) telecommunications system in the interplexed dual channel 117.6 kilobits per second (kbps) and 2.45 kbps telemetry. This mode, originally designed for only Venus encounter, was also used at Mercury despite significantly less performance margin. Detailed analysis and careful measurement of system performance before and during flight operations allowed critical operational decisions, which made maximum use of the system capabilities.
    • Experientially Guided Robots

      Merriam, E. William; Becker, Joseph D.; Bolt Beranek and Newman Inc. (International Foundation for Telemetering, 1974-10)
      This paper argues that an experientially guided robot Is necessary to successfully explore far-away planets. Such a robot is characterized as having sense organs which receive sensory information from its environment and motor systems which allow it to interact with that environment. The sensori-motor information which it receives is organized into an experiential knowledge structure and this knowledge in turn is used to guide the robot's future actions. A summary is presented of a problem solving system which is being used as a test bed for developing such a robot. The robot currently engages in the behaviors of visual tracking, focusing down, and looking around in a simulated Martian landscape. Finally, some unsolved problems are outlined whose solutions are necessary before an experientially guided robot can be produced. These problems center around organizing the motivational and memory structure of the robot and understanding its high-level control mechanisms. This paper discusses a project which is attempting to develop the "mind" of' a robot which will be capable of experiencing its environment, storing sensori-motor information, and then using its accumulated knowledge to guide its future actions. In Section I, we describe the sort of behavior that an experientially guided robot might exhibit, and we give some reasons why we might want such a thing. Then, in Section II, we discuss the current state of our project, and in Section III we indicate some important issues that are as yet unresolved.
    • The Impact of Robots on Planetary Mission Operations

      Hooke, A. A.; Larman, B. T.; Whitney, W. M.; California Institute of Technology (International Foundation for Telemetering, 1974-10)
      For reasons of efficiency and safety, unmanned roving vehicles sent to explore remote planetary surfaces must carry out some of their tasks without step-by-step human control. To realize the benefits that such semiautonomous machines can provide will require some changes in how planetary missions axe presently planned and conducted. Specifically, mission profiles will have to be based on tasks or functions rather than sequences of timed events, scientists will have to be more directly involved in the control of their instruments, and present ideas concerning spacecraft safety, testing and simulation of vehicle performance, telemetry design, and ground-system implementation must be reexamined.
    • Simulation of PCM Data Utilizing a General Purpose Computer

      Shultenburg, K. G.; Ehrsam, E. E.; Control Data Corporation; Vandenberg Air Force Base (International Foundation for Telemetering, 1974-10)
      Due to the increased complexity and capabilities of modern missile telemetry systems, it has become increasingly difficult to provide an effective yet flexible simulation capability for the verification and validation of PCM decommutation systems. Control Data Corporation, under contract with the Space and Missile Test Center (SAMTEC) at Vandenberg Air Force Base, California, recently completed the development of a powerful and flexible simulation system utilizing a CDC 3300 computer. This Telemetry Decom Validation System (TDVS) now allows personnel to develop a simulated PCM data stream using a telemetry-oriented compiler to generate telemetry instructions. The compiled program can then be executed in a microprogrammable processor which generates the defined PCM stream through the interpretation of the specially designed instruction set output by the compiler. Data can be simulated at rates up to 2 megabits using any of the seven IRIG code conventions or Miller Code.
    • Method for Calculating the Pre-Emphasis Schedule for an FM/FM Telemetry System Based on Optimum Performance

      Rosen, Charles; Microcom Corporation (International Foundation for Telemetering, 1974-10)
      This paper will describe a system for calculating the pre-emphasis schedule and the required receiver IF bandwidth for FM/FM Telemetry Systems (Frequency Division Multiplexing. An investigation of the procedures presently in use, disclose that system engineers calculate their system pre-emphasis based on the 3/2 Power Law, for proportional bandwidth systems and a 6 db per octave taper for constant bandwidth systems. Systems using both proportional and constant bandwidth channels are usually left to empirical methods. The total deviation and the receiver bandwidth is assumed using empirical values previously found successful. So far, an investigation has not shown any exact technical basis for the selection of the total deviation or the receiver bandwidth to be utilized in a system.
    • A Coding Algorithm for Random Access Satellite Systems

      Wu, W. W. (International Foundation for Telemetering, 1974-10)
      In satellite communications systems, when a code-division scheme is desirable for random multiple access, specific codes must be constructed for the users in the system to share the same satellite channel. This paper develops a coding algorithm for such purposes by means of a binary matrix. Step-by-step procedures are separately described. An example demonstrates the usefulness of the algorithm, and its advantages and disadvantages are discussed. Finally, a problem for future work is suggested.
    • Space Shuttle Communications-Wideband Direct Link Signal and System Design

      Batson, Bartus H.; Huth, Gaylord K.; Lyndon B. Johnson Space Center; Axiomatix (International Foundation for Telemetering, 1974-10)
      This paper describes the design of a wideband S-band communications link from the Space Shuttle Orbiter to a ground-based terminal. This link will be used for transmission of television, digital data (various rates), or analog data, and is of interest because of the presence of bandwidth, power, and hardware constraints. The procedure followed to arrive at an overall signal and system design is outlined, and system performance margins are presented for various operational configurations. Finally, the growth potential of this link for digital data transmission is discussed.
    • Carrier Tracking, Bit Synchronization, and Coding for S-Band Communications Links

      Odenwalder, J. P.; LINKBIT Corporation (International Foundation for Telemetering, 1974-10)
      This paper presents the results of a study of the performance of Viterbi-decoded convolutional codes in the presence of nonideal carrier tracking and bit synchronization. A constraint length 7, rate 1/3 convolutional code and parameters suitable for the Space Shuttle coded communications links are used. Mathematical models are developed and theoretical and simulation results are obtained to determine the tracking and acquisition performance of the system. It is shown that the combined E(b)/N(o) degradation due to nonideal carrier tracking and bit synchronization over that required for the ideal tracking case can be held to less than 1.5 dB and that combined carrier tracking and bit timing can be acquired in only a few seconds for the parameters and operating ranges of the Space Shuttle coded communications links.
    • Design of the Mariner Jupiter/Saturn 1977 Telemetry System

      Wood, Gordon E.; Risa, Thomas; California Institute of Technology (International Foundation for Telemetering, 1974-10)
      In 1977 NASA will launch two spacecraft to perform scientific investigations of the Jupiter and Saturn planetary systems. The science payload includes a total of 10 instruments to support both the interplanetary cruise and planetary encounter phases. These will be the first launches of a new generation of Mariner-class spacecraft designed for outer-planet missions. The telemetry system design for these missions was especially challenging because of extreme communication ranges (1.5 X 10⁹ km), high data rate requirements (up to 115.2 kb/s), and more stringent data quality requirements than previous Mariner missions. This paper discusses the evolution and design of the Mariner Jupiter/Saturn 1977 telemetry system and presents the performance anticipated therefrom.
    • The Viking Lander Telemetry Subsystem

      Patton, Victor V. C.; Martin Marietta Corporation (International Foundation for Telemetering, 1974-10)
      The Viking Program will place two orbiting spacecraft around Mars in the summer of 1976. Each spacecraft will contain a Mars soft lander. The Telemetry Subsystem is that group of electronics on the Viking Lander which interfaces all sources of operational and science data, stores and conditions that data, and provides it to the communications subsystem in appropriate form for RF transmission.
    • 117.6 Kilobit Telemetry from Mercury-A Major Deep Space Telecommunication Advance

      Clarke, Victor C.; California Institute of Technology (International Foundation for Telemetering, 1974-10)
      For nearly eight hours on March 29, 1974, Mariner 10 transmitted imaging telemetry in real time at 117.6 Kbps from Mercury. During this time, 562 very high quality frames were received, even though the bit error rate was only about 1 in 40. The transmission of 117.6 Kbps from Mercury is a magnificent telecommunications achievement, which permitted an order of magnitude increase in imaging science data return. The Mariner 10 imaging scientists' requirements, simply stated, were to obtain maximum area coverage at highest spatial resolution. More precisely, they desired photomosaics which were equivalent to the best earth-based pictures on the Moon, i.e., about 1 km resolution. The purpose of this paper is principally to relate the methods by which these "desirements" were translated into measurable telecommunication system requirements and some of the attendant tradeoffs. Additionally, same of the steps taken to achieve their goal are recited.
    • Deep Space Telecommunications-Pioneer Mission to Jupiter

      Heist, E. K.; TRW Inc. (International Foundation for Telemetering, 1974-10)
      The Telecommunication subsystem for the Pioneer 10 and 11 spacecraft is described in terms of the exacting design requirements which have been met and the operational performance which has been achieved. Those features which are unique or novel and which contribute substantially to our knowledge of advanced techniques for future interplanetary missions, are emphasized. The discussion includes earth-pointing of the spacecraft high gain antenna by an on-board conical scan system, tracking, telemetry, and command functions at multi-million kilometer distances complicated by round trip communication delays of 90 minutes, and the versatility of special data formats which cater to certain instrument high rate sampling requirements during selected phases of the mission. With the successful flyby of the planet Jupiter by Pioneer 10 in December 1973, the technology and experience for much more ambitious, challenging, and complex missions to the outer planets has been demonstrated.
    • Martian and Lunar Science with Remotely-Controlled Long-Range Surface Vehicles

      Jaffe, Leonard D.; Choate, Raoul; California Institute of Technology; TRW Systems Group (International Foundation for Telemetering, 1974-10)
      Science objectives are outlined for long surface traverse missions on Mars and the moon, with remotely-controlled roving vehicles. Series of candidate rover science payloads are proposed, varying in purpose, development needed, cost, and weight (35 to almost 300 kg). A high degree of internal control will be needed on the Mars rover, including the ability to carry out complex science sequences. Decision-making by humans in the Mars mission includes supervisory control of rover operations and selection of features and samples of geological and biological interest. For the lunar mission, less control on the rover and more on earth is appropriate. Operational problem areas for Mars include control, communications, data storage, night operations, and the mission operations system. For the moon, science data storage on the rover would be unnecessary and control much simpler.
    • On-Board High Frequency Data Processing

      Maschhoff, Robert H.; Gultron Industries (International Foundation for Telemetering, 1974-10)
      On-board processing of high frequency analog data, such as that derived from vibration and acoustic sensors, offers the telemetry engineer three highly significant advantages over traditional fm/fm transmission of such data. When combined with PCM techniques the result is (1) bandwidth compression, (2) single rf data link, and (3) substantially higher data accuracy. In this processing technique only data representative of the power spectral density of the sensed waveform is transmitted to the ground station. By shifting the data processing function to the on-board telemetry system and transmitting only the processed data, the required transmission channel bandwidth is greatly reduced. As a result of this bandwidth compression the high frequency data can be pulse code modulated. Two significant advantages thereby ensue. The first is that data from multiple sources may now be transmitted over a single rf data link. The second advantage is that the data accuracy is greatly increased.
    • Adaptive Bit Synchronizer

      Halpern, Peter H. (International Foundation for Telemetering, 1974-10)
      The motivation for adapting loop bandwidth is reviewed. The ideal loopwidth is shown to be a monotonic function of the ratio of two statistical measurements, namely the input SNR and the present uncertainty of proper phase. This is seen from a relatively simple viewpoint of how to combine independent measurements of the same quantity. Means for measuring the statistical quantities are described. Simple means for varying loop widths are described. Experimental results of the adaptive bit synchronizer are compared with a classical bit synchronizer.
    • Aeroflight Communications and RF Navaids

      Lilly, Douglas S.; Lyndon B. Johnson Space Center (International Foundation for Telemetering, 1974-10)
      The Space Shuttle Program concept of a low cost, reliable and reusable orbital vehicle has proven to be a driving function in systems design and integration. Extensive use of existing designs to satisfy these requirements has been effectively employed in the aeroflight systems. Appropriate planning and a careful appraisal of maturity, cost, performance, vehicle burdens, and operational flexibility were completed prior to a system choice. The aerial navigation and landing systems selected for the orbital vehicle are described and their interfaces with the control and navigation system discussed.
    • Rendezvous Radar for Space Shuttle Orbiter Vehicle

      McQuillan, W. F.; Bologna, A. W.; Calabrese, D. M.; Rockwell International Corporation (International Foundation for Telemetering, 1974-10)
      To successfully complete many of the Space Shuttle Program proposed missions involving Orbiter rendezvous with orbiting satellites, some method of detecting and tracking remote targets is desirable. Several studies to establish the requirements for a rendezvous radar system indicated the feasibility of the concept. Extensive application of state of the art components is possible, and system parameters can be determined in a general sense to avoid impacting Orbiter development. Considerations of size and weight are necessary to the choice of any system, as well as the operational capabilities of the candidate. Two radar systems appeared to meet the requirements: a microwave radar and a laser radar. Although the laser radar was highly competitive, difficulty was encountered in assessing the operational risk of such a system. The microwave radar was therefore selected as the rendezvous sensor most suitable for Space Shuttle Program use.
    • Space Shuttle Communications and Tracking System

      Batson, Bartus H.; Johnson, John H.; Lyndon B. Johnson Space Center (International Foundation for Telemetering, 1974-10)
      This paper provides an overview of communications and tracking for the Space Shuttle Program. The Shuttle Program itself is briefly described, and communications and tracking requirements and capabilities are discussed for the various phases (ascent, on-orbit, and reentry/ landing) of a Shuttle mission.
    • Atmospheric Monitoring Using Infrared Heterodyne Radiometry

      Peyton, Bernard J.; Cutler-Hammer (International Foundation for Telemetering, 1974-10)
      Atmospheric constituents have unique vibrational-rotational signature lines within the infrared spectrum and the signature intensities and line shapes vary with the constituent concentration and the atmospheric density. The recent development of stable, single frequency, single-mode laser local oscillators and nearly quantum-noise-limited heterodyne receivers have permitted the development of infrared heterodyne radiometers (IHR's) which provide good sensitivity and excellent specificity for the remote examination of individual atmospheric constituent signature lines. A 9 to 11 μm IHR employing a CO₂ laser local oscillator has been developed and can be used to resolve the spectral signature of atmospheric constituents such as SO₂, O₃ C₂H₄, and NH₃. The IHR has a bandwidth of 100 MHz (33 x 10⁻³ cm⁻¹) and a minimum detectable power spectral density of 5.4 x 10⁻²⁴ W/Hz for a 1-second integration time. For atmospheric monitoring applications the IHR telescope collects the thermal energy radiating from the earth at: (1) a clear spectral window, and (2) a spectral region in which the signature lines of the constituent gases at various layers of the atmosphere will be energized by the upwelling thermal radiation. When the vertical temperature distribution of the atmosphere is known, the concentration of the atmospheric constituent gas can be determined as a function of altitude from the radiance data collected at the IHR using an iterative mathematical technique.