• NASA DEEP SPACE NETWORK OPERATIONS CONTROL

      Weisman, William D.; Jet Propulsion Laboratory California Institute of Technology (International Foundation for Telemetering, 1982-09)
      Overall direction, coordination and control of the real-time activities of the NASA Deep Space Network (DSN) is the responsibility of the Network Operations Control Team located at the Operations Control Center at JPL in Pasadena. Real-time operation of the DSN is a complex task, requiring efficient interaction among operations personnel, hardware, software, communications and mechanical systems. Control is maintained by the team at JPL through allocation of responsibility for specific operational facilities to specific team members. The Network Operations Control Team is comprised of an Operations Chief, a Track Chief, and one or more Deep Space Station (DSS) Controllers. The Operations Chief is responsible for overall performance of the Operations Control Center, and provides a single point of interface with the Control Center to end user organizations. The Track Chief is responsible for overall performance of the DSN as a facility, while the Station controllers are assigned responsibility for monitoring and coordinating the operational activities at individual Deep Space Stations.
    • NASA DEEP SPACE NETWORK OPERATIONS ORGANIZATION

      Chafin, Roy L.; Jet Propulsion Laboratory California Institute of Technology (International Foundation for Telemetering, 1982-09)
    • NASA DEEP SPACE NETWORK OPERATIONS PLANNING AND PREPARATION

      Jensen, W. N.; Jet Propulsion Laboratory California Institute of Technology (International Foundation for Telemetering, 1982-09)
      The first contact that a project or user has with NASA Deep Space Network (DSN) Operations is with the Operations Planning Group. This group establishes an early interface with the user’s planning organization to educate the user on DSN capabilities and limitations. It negotiates and documents DSN support commitments to provide a firm foundation for developing the project support plans. The group develops plans and schedules to prepare the network for project support. Part of this activity is to monitor and evaluate the testing and training required in preparation of mission support. The DSN Operations Planning Group provides a team of one or two individuals dedicated to each user or project depending on the magnitude of the coordination activity. This team works through the planning and preparation activity and continues to support the project after the spacecraft launch to the end of the mission. The team provides a coordinating role after launch. It also provides planning and preparation for specific events such as planetary encounters.
    • NASA DEEP SPACE NETWORK OPERATIONS SCHEDULING

      Enari, Dennis M.; Jet Propulsion Laboratory California Institute of Technology (International Foundation for Telemetering, 1982-09)
      Network Operations Scheduling provides the scheduling management for allocating the NASA Deep Space Network resources to support flight projects and other authorized users. As a part of Network Control Center Operations, it is the task of Network Operations Scheduling to forecast, detect conflicts, support conflict resolution and schedule the allocation of the network. The products of scheduling provide management and users of the network with information that will give them visibility concerning network loading, mission support and facility utilization. Subsequent management decisions based on this information concern advanced Fiscal budgeting and station shift staffing. The structure of the scheduling system provides an orderly advancement of general user requirements during the early stages of planning to an expanded detailed set of requirements at the final stage of planning.
    • NASA DEEP SPACE NETWORK PERFORMANCE ANALYSIS

      Bartok, Carol DiNolfo; Jet Propulsion Laboratory California Institute of Technology (International Foundation for Telemetering, 1982-09)
      Network performance analysis is an essential element in the operation of the NASA Deep Space Network. The primary function of the Deep Space Network is to support the communication, radio navigation and radio science needs of the flight project users. As a part of Network Control Center Operations, it is the task of the Performance Analysis Group to provide the Network with the analysis support required to assure that actual Network performance meets or exceeds committed levels throughout the mission. The Performance Analysis Group provides time-critical monitoring and analysis for the Tracking, Telemetry and Command Systems of the Deep Space Network. The group is organized into units that are specialized to provide the functional requirements of each system. It provides failure analysis to determine causes of Network failures and data outages, as well as providing technical assistance to the operations organization for recovery from failures. It generates the predictions used to point the antennas, acquire the radio frequency, and to validate the monitored Network performance. Also, it provides technical interfaces with the user projects as required for the smooth running of the operation. As a result of this specialized expertise, complex and time-critical problems that arise receive an immediate decision-making response.
    • A NEAR-OPTIMUM RECEIVER STRUCTURE FOR THE DETECTION OF M-ARY OPTICAL PPM SIGNALS

      Dolinar, Sam; Jet Propulsion Laboratories (International Foundation for Telemetering, 1982-09)
    • A NEW ORTHOGONAL MULTIPLEX SYSTEM

      shan, Zhang Qi; Zhihua, Li; Beijing Institute of Aeronautics and Astronautics; Qinghua University (International Foundation for Telemetering, 1982-09)
      The basis of mathematics which can form a telemetering system is orthogonal functions. Three kinds of orthogonal functions are used up to now. First of them is sine and cosine functions. Second one is block pulse functions. The third one is walsh functions. Their corresponding systems are FDM, TDM and SDM. There are also other orthogonal sets which can form telemetering system, such as Legendre polynomials and Hermite polynomials. Hewever. They are too complex for engineering practice. Except these functions mentioned above, is there any other orthogonal functions which is suitable for engineering practice? In this paper we presented a new type of orthogonal functions. Its construction is similar to Walsh functions. The amplitudes of the functions are +1, -1 and 0. In the sence that they close the gap between walsh functions and block functions, it is called Bride functions. The definition and properties are discussed in more detail here. The construction of system is also similar to that of SDM.
    • A NONMYSTICAL TREATMENT OF TAPE SPEED COMPENSATION FOR FREQUENCY MODULATED SIGNALS

      Solomon, Otis M., Jr.; Sandia National Laboratories (International Foundation for Telemetering, 1982-09)
      In this paper, the problem of non-constant tape speed is examined for frequency modulated signals. Frequency modulation and demodulation are briefly reviewed. Tape speed variation is modeled as a distortion of the independent variable of a frequency modulated signal. This distortion produces an additive amplitude error in the demodulated message which is comprised of two terms. Both depend on the derivative of time base error, which is the flutter of the analog tape machine. The first term depends on the channel’s center frequency and frequency deviation constant as well as flutter, while the second depends solely on the message and flutter. The relationship between the additive amplitude error and manufacturer’s flutter specification is described. Relative errors and signal-to-noise ratios are discussed for the case of a constant message to gain insight as to when tape speed variation will cause significant errors. An algorithm which theoretically achieves full compensation of tape speed variation is developed. The algorithm is confirmed via spectral computations on laboratory data. Finally, the algorithm is applied to field data. The reference is a temperature signal which is a non-zero constant, and the message is a pressure signal. The spectrum of the uncompensated message is clearly contaminated by the additive amplitude error, whereas the spectrum of the compensated message is not. Incorporation of this algorithm into the data-playback/data-reduction procedures is shown to greatly improve the measurement signal accuracy and quality. The treatment is nonmystical in that all derivations are directly tied to the fundamental equations describing frequency modulation and demodulation.
    • AN OVERVIEW OF CONFORMAL ANTENNA DESIGN TECHNIQUES USEFUL FOR TELEMETRY APPLICATIONS

      Jones, Howard S., Jr.; Formerly with Harry Diamond Laboratories (International Foundation for Telemetering, 1982-09)
      Several conformal antennas useful for telemetry applications are described. These antennas make use of dielectric-loaded cavity, edge-slot, microstrip, and dielectric rod radiator design techniques. Critical design parameters, modes of radiation, and theoretical considerations are discussed, as well as intrinsic properties and characteristics of the dielectric materials used. Experimental data relating to impedance, gain, polarization, and bandwidth are given. Also presented are prototype telemetry antennas and performance characteristics. The conformal antennas are flushmounted and designed as an integral part of the body structure. These antennas are electrically small and compact, occupying minimial space. They can be designed efficiently for operation in the telemetry frequency band to produce the desired radiation pattern coverage. Simplified construction and low cost are among the other advantages realized.
    • PERFORMANCE OPTIMIZATION OF PCM/SCO TELEMETRY SYSTEMS

      Jeske, Harold O.; Sandia National Laboratories (International Foundation for Telemetering, 1982-09)
      These hybrid TM system design procedures indicate how PCM channel performance comparable with that obtainable from an optimally designed PCM/FM transmission system may be obtained even though numerous subcarrier channels are included in the system. Optimal design goals are those that permit satisfactory telemetry system operation with a minimum of transmitted power. By careful control of the transmitter modulation levels and the use of predetection filtering during playback, a lowering of the PCM channel’s threshold, equivalent to at least quadrupling the transmitter power over conventional practices, is obtained. This report briefly discusses the design objectives of FM/FM and PCM/FM systems followed by a more detailed discussion of hybrid systems using FM subcarriers above the PCM signal on the baseband. A simplified, but comprehensive, discussion of FM sidebands is presented in the appendices to aid in understanding the limits and restrictions in this hybrid TM system design procedure.
    • PHASE AND FREQUENCY TRACKING CONSIDERATIONS FOR HETERODYNE OPTICAL COMMUNICATIONS

      Kaufmann, John E.; Massachusetts Institute of Technology (International Foundation for Telemetering, 1982-09)
      In heterodyne optical communications, phase or frequency tracking is generally needed to avoid performance degradation when signaling in the presence of laser frequency jitter and Doppler shifts. This paper examines a phase-lock loop approach for BPSK and two forms of frequency tracking for MFSK. Using a statistical model for laser frequency instability, the performance of these schemes is calculated by a linear analysis of the tracking loop in the small-error regime.
    • PLANETARY SOIL WATER ANALYZER (PSWA) PROTOTYPE

      Cashin, William F.; Anderson, Duwayne M.; Ball Aerospace Systems Division; State University of New York (International Foundation for Telemetering, 1982-09)
      A microprocessor-based differential scanning calorimeter is being designed for eventual use in planetary soil water analysis. The uniqueness of this effort is in the use of the microprocessor as an integral section of the system control loops, instead of as merely an auxilary processor of output data. The use of differential scanning calorimetry is advantageous in determining water content of soil samples. The basic idea is to use two matched ovens, one with a soil sample included. The average temperature of the ovens is forced to track a desired programmed temperature (normally a slow ramp) with one control loop, while a second control loop forces the oven temperatures to be equal, even during a transition. The power necessary to keep the temperatures equal is monitored, containing information as to the transition energy, and thus the water content at programmed water transition temperatures. This approach uses the microprocessor to close both of the loops, taking oven sensor temperatures as an input, and providing power duty cycles as outputs. In actuality, two microprocessors are used - a slave to accumulate and process sensor information, and a master to generate the loop control, output data control, and temperature program control. The PSWA performance is compared to a state-of-the-art commercial instrument using analog loop control. The major advantage of the microprocessor loop control utilized in the PSWA is the capability of remote operation, including remote alignment and adjustment. Further advantages include accommodation of oven changes with software reprogramming, a flexible single oven capability, correction for system nonlinearities using software, and auto gain and auto zero control for the sensor circuitry. The analog loop control approach has somewhat better sensitivity, resolution, and noise performance. The current phase of the development of the PSWA is a feasibility study and circuit design, performed for the Planetary Geology Program Office, NASA Headquarters. The next developmental phases would include breadboarding, software design, testing, and evaluation. In conclusion, this instrument is a significant advance in the state-of-the-art for automatic water measurements, and will be of great value in further planetary exploration.
    • POLARIZATION DIVERSITY CAPABILITY THROUGH SAMPLING AT THE RF LEVEL

      Endler, Harvey; Turner, William; Electra Magnetic Processes, Inc. (International Foundation for Telemetering, 1982-09)
      Novel RF circuitry for selecting the stronger of two telemetry signals (RHCP or LHCP) is presented. Polarization diversity capability with uninterrupted data flow can be achieved without using two expensive single channel data receivers and a diversity combiner. In certain dedicated systems only a single AM/FM receiver is required. This paper describes the RF signal processing and logic circuitry of a developed system and describes how it is applied in a lightweight polarization diversity single channel monopulse tracking system.
    • POWER COMBINING AND SIGNAL ROUTING IN THE GALAXY TT&C EARTH STATION

      KNOX, K. D.; MALLETTE, L. A.; HUGHES AIRCRAFT COMPANY (International Foundation for Telemetering, 1982-09)
      This paper describes the signal routing and power combining function of the C-band uplink frequency signals in the Galaxy TT&C earth station.
    • POWER EFFICIENT OPTICAL COMMUNICATIONS FOR SPACE APPLICATIONS

      Lesh, James R.; Supervisor, Communications Concepts Research Jet Propulsion Laboratory (International Foundation for Telemetering, 1982-09)
      Optical communications technology promises substantial size, weight and power consumption savings for space to space high data rate communications over presently used microwave technology. These benefits are further increased by making the most efficient use of the available optical signal energy. This presentation will describe the progress to date on a project to design, build and demonstrate in the laboratory an optical communication system capable of conveying 2.5 bits of information per effective received photon. Such high power efficiencies will reduce the need for photon collection at the receiver and will greatly reduce the requirements for optical pointing accuracy, both at the transmitter as well as the receiver. A longer range program to demonstrate even higher photon efficiencies will also be described.
    • PRESAMPLING FILTERING, SAMPLING AND QUANTIZATION EFFECTS ON THE DIGITAL MATCHED FILTER PERFORMANCE

      Chang, Horen; Stanford Telecommunications, Inc. (International Foundation for Telemetering, 1982-09)
      Due to the increased capability and reduced cost of digital devices, there has recently been a growing trend to digitize the matched-filtering data detector in the receiver. Comparing with an idealized integrate-and-dump analog matched filter, the digital matched filter (DMF) requires more Eb /No in order to achieve the same bit error rate performance because of the presampling filtering, sampling, and quantization effects. This paper analyzes the performance degradation resulting, separately and jointly, from these three effects. Quantitative results are provided for commonly chosen sets of design parameters. For a given performance degradation budget and complexity limitation, these results could be applied to choose the optimum DMF design parameters including the presampling filter bandwidth, the sampling rate, the number of quantization bits, and the spacing between adjacent quantization levels.
    • PROCESSOR TECHNOLOGY OFFERS UNREALIZED FLEXIBILITY IN TOMORROW’S TELEMETRY GROUND STATIONS

      THOM, GARY A.; AYDIN MONITOR SYSTEMS (International Foundation for Telemetering, 1982-09)
      Today’s state of the art in semiconductor technology coupled with innovative computer architecture techniques can provide tomorrow’s telemetry industry with advanced ground station capabilities. Computer systems have traditionally been used to process all of the telemetry data. As data transmission speeds increase, the computer system can no longer handle real time processing so preprocessors are being used to handle the additional computational requirements. An alternative approach is to embed special purpose processors into applicable elements of the front-end equipment. These processors can be optimized for the function they are to perform, which prevents under utilization of processing power and enhances the flexibility and performance of the front-end element. These special purpose processors take up little real estate when implemented with todays LSI and VLSI semiconductors. The modules which are ideally suited for this type of technology are serial data correlators, decommutators, real time data correction, engineering units conversion, quick look display, data simulation and many special application modules. These processing elements provide the building blocks for a very powerful, cost effective family of modular telemetry and communications products for the 80’s and beyond.
    • PROGRAMMABLE TELEMETRY TEST SYSTEM

      GUADIANA, JUAN M.; NAVAL SHIP WEAPON SYSTEMS ENGINEERING STATION (International Foundation for Telemetering, 1982-09)
      The U.S. Navy has traditionally operated several missile ranges around the world. However, as the exercises it conducts require greater areas and improved security, it has taken the more ambitious exercises to open ocean, away from ranges. Portable shipboard Telemetry Receiving Systems are designed based on similar methods to those used by range system designers. However, the portable field station must be very small (less then 600 lbs) and system designers are hard pressed to include sophisticated hardware to offset the lower performance of light weight front ends. After the design stage, it is always found that no further weight or volume may be allocated to test equipment. The result has been to practice exercising the live round (missile) for the purpose of testing the ground station. This Test System was designed to meet a need for a portable system to test shipboard telemetry systems used for evaluating performance of missile systems in the surface missile fleet. The technical information presented describes the capabilities of a small test system that is programmable to accurately simulate any missile in the current Navy inventory. It provides test and calibration signals so that telemetry system status may be verified, giving the field operator unprecedented confidence in the station’s condition. The Programmable RT Test System is a product of Navy’s Engineering Initiative Program which supports limited engineering efforts designed to enhance service to the fleet.
    • PULSE CODE MODULATION TELEMETRY

      Law, Eugene L.; Pacific Missile Test Center (International Foundation for Telemetering, 1982-09)
      This paper discusses the performance of pulse code modulation/frequency modulation (PCM/FM), pulse code modulation/phase modulation (PCM/PM) and phase shift keying (PSK) in the “real-world” of range telemetry. The topics addressed include: 1. Radio frequency (RF) spectra 2. Bit error rate (BER) versus pre-detection signal-to-noise ratio (SNR) 3. Peak carrier deviation 4. Premodulation and receiver predetection filtering 5. PCM codes 6. Magnetic recording The purpose of this paper is to provide the reader with information needed to choose the best modulation method, PCM code, premodulation filter bandwidth and type, receiver settings, and recording method for a particular application.
    • 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.