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.

      Michaud, Colonel Normand; Hollander, Sidney; Hq Air Force Satellite Control Facility (AFSCF); The Aerospace Corporation (International Foundation for Telemetering, 1982-09)
      This paper updates the previous work,¹ which described the overall telemetry and data processing capabilities of the Data System Modernization (DSM) system being developed at the Air Force Satellite Control Facility (AFSCF). Having passed the System Critical Design Review milestone, the DSM program is proceeding with the design and implementation of various elements which support both the real-time routing, processing, storage, and display of satellite telemetry data, as well as the off-line recall of raw or processed telemetry data for trend analysis and satellite operations planning. A Data Distribution Element routes data received from 13 Remote Tracking Station (RTS) antennas and other sources to dedicated telemetry processing elements located within eight Satellite Test Center (STC) Mission Control Complexes (MCCs), a Range Control Complex (RCC), and the System Development and Test Laboratory (STDL). Two types of telemetry preprocessing elements are provided: one for processing telemetry data of rates less than 32 kilobits per second (or for processing selected measurands from telemetry data of rates up to 1.024 megabits per second), and the other for processing high-rate telemetry up to 5 megabits per second. Computer programs executing within one of two large mainframe computers and a Telemetry Contact Support Equipment Group in each MCC selectively decommutate, compress, calibrate, and store the telemetry data. Once processed, the data is formatted into unique, user-defined displays for real-time or post-contact analysis. Interfaces are also provided to satellite commanding routines for the authentication or verification of commands that have been transmitted to the satellite during the contact. Additional computer programs provide the capability to extract designated measurands from the processed telemetry history files, and format them, into messages for near realtime transmission to users remotely located from the STC. A capability is also provided to interface future telemetry preprocessing equipment, such as that required to support multiple scientific payloads aboard the Space Shuttle.

      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.)

      Corlis, N. E.; Hauser, G. C.; Sandia National Laboratories (International Foundation for Telemetering, 1982-09)
      This paper describes an eight megabit bubble memory used as a mass memory storage device on a high altitude helium filled balloon flight package. The balloon flight designated as Gamma Ray VI, a coordinated effort of Sandia National Laboratories and Bell Laboratories, was conducted in the fall of 1981 at Alice Springs, Australia. Eight onemegabit Intel bubble modules were mounted on a custom designed multilayer printed wire board to maximize the memory in the available space. A microprocessor based data interface was designed to test and control the bubble memory. The selection of bubble memory modules for this application, the design considerations of the bubble printed wire board and the microprocessor interface are discussed. The flight test and results of Gamma Ray VI are described. Future developments and applications are briefly presented.

      Ryerson, D. E.; Lopez, A. A.; Sandia National Laboratories (International Foundation for Telemetering, 1982-09)
      A Seafloor Earthquake Measurement System for measuring strong motion seismic data has been developed and tested by Sandia National Laboratories as part of the Department of Energy Offshore Instrumentation Program. The system’s function is to gather data for the design and regulation of offshore structures such as oil platforms and pipelines. The seafloor package is a self-contained unit capable of operating unattended for up to one year with data readout on command via an underwater acoustic telemetry system. One of the problems with such a system is the large memory required to store seismic data. This memory also must consume very little power to conserve battery life. To meet these conditions a combination low-power CMOS buffer memory and a one-million-bit magnetic bubble main memory with switched power was developed. This paper describes these memories and how they are controlled by a microprocessor to save the “best” data since the last data readout.

      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.

      Viswanathan, R.; S.C. Gupta; Southern Methodist University (International Foundation for Telemetering, 1982-09)
      We investigate the performance of a likelihood receiver for the detection of frequency hopped multilevel frequency shift keyed signals (FH-MFSK) to a mobile user operating in a multi user environment. The analysis assumes synchronous transmission from base to mobiles operating in an isolated cell-cellular system and a simplified mobile radio channel. The likelihood receiver attempts to discriminate spurious rows of the decoded matrix of a user, which consists of samples from an exponential-mixture, from the correct row, which consists of samples from a simple exponential density, by computing the log-likelihood statistic for each row. It declares the row possessing the minimum value as the correct row, corresponding to the word transmitted to the user. An approximate analysis of the probability of bit error of this receiver by three means, viz. (i) large sample approximation (ii) simple Chernoff bound and (iii) Chernoff bound with central limit theorem, reveals that the likelihood receiver is only marginally superior to a hard limited combining receiver.

      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.
    • Utilization of Fiber Optics in Large Scale Landline Telemetry Systems

      Saulsberry, Garen J.; Willis, James L.; New Mexico State University (International Foundation for Telemetering, 1982-09)
      The large-scale landline telemetry system may benefit from the application of fiber optics. With present technology, practical means exist to design, implement, and test longdistance, data-transmission systems using fiber optics. Fiber optics and Computer Automated Measurement and Control (CAMA) equipment provide application and tradeoff advantages over a hard-wire system. Procedures for equipment verification must be developed to confirm and verify system performance of the design criteria. Practical computations may be made using values representative of actual system performance. A solution is provided to a typical data transmission problem.

      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.

      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.

      Nicolais, Ray; Ellis, Donald H.; AEROSYSTEMS ASSOCIATES; AYDIN VECTOR Division (International Foundation for Telemetering, 1982-09)
      With the advent of digital technology in aircraft systems, the need for advancements in digital data acquisition systems for flight testing became apparent. A thorough review of aircraft systems integration employing the MIL-STD-1553 multiplex data bus revealed the need for flight test systems that incorporate the advanced digital techniques and provide an interface to the data bus. This paper provides an overview of the MIL-STD-1553 requirements including word structure and protocol, with special emphasis on the requirements for synchronization and time tagging of the data acquired from the bus. The data bus is a serial digital transmission system for interchange of control signals, status and data between equipment internal to the aircraft (or other vehicle). The basic multiplexing technique is Time Division Multiplexing (TDM) with the information coded in 20-bit (16-bit data) words. The transmitted waveform is biphase operating at a bit rate of 1.0 megabit per second. Transmissions are bi-directional on a twisted pair shielded cable. The requirements for a bus monitor unit which interfaces with the data bus for acquisition and processing of information are described. The design for a Programmable Bus Monitor (PBM) is detailed. The PBM provides a highly flexible and effective interface between the MIL-STD-1553 data bus and an advanced digital flight test system.

      Stevens, Walter H.; Ryan, John J.; AYDIN VECTOR Division (International Foundation for Telemetering, 1982-09)
      A description of a unique approach for construction of modular data acquisition systems using a family of standard thick film hybrid circuits. Each module is described in terms of its universal function and examples of various system constructions are explained. Demonstrating the advantages of this approach in offering minimum size, weight, and high reliability, with resonable cost for various program applications.

      Tinsley, Harold D.; SCI Systems, Inc. (International Foundation for Telemetering, 1982-09)
      The MX Instrumentation Multiplexer Set is used to acquire data during test flights of the MX Missile. The Multiplexer Set consists of a Multiplexer Programmer Controller Unit (MU), from 2 to 32 Remote Multiplexer Units (RU’s), and any number of Power Supply Verifier Units (PSV’S). The primary purpose of the MU is to operate as the programmable system controller, acquire local data inputs, and format this data along with data from the RU’s in a PCM Output. The RU’s interface to the MU via Instruction and Reply Data Buses providing remote data acquisition. The PSV’s provide an accurate stimulus voltage to the analog sources along with a control to offset the analog signal for test verification. Thirty-one of the possible 32 RU’s connect to the MU by two pairs of vehicle data buses, while the remaining RU is connected via the umbilical data bus. This ground resident RU is identical to the flight RU’s, but its functional requirement is quite different as it is primarily used to load and verify MU programs. Each of the vehicle data buses can be up to 130 feet in length with a 250 foot length allowed for the umbilical bus. An ideal terminated bus is not feasible in the MX application since the bus configuration changes as the missile stages. Staging will produce opens or shorts on the cable; to insure proper operation of all remaining RU’s on the bus, the interface isolation transformer incorporates both voltage and current windings to provide maximum secondary signal level with minimum reflection distortion. The data bus operates at 3.2 MHz using a Manchester II coded signal. The MU can sample 160 local differential analog channels that are programmable in gain, off-set, and to a maximum rate of 170,665 samples per second. A flexible grouping of 8 discrete inputs from the 96 discrete channels is programmable to a rate of 51,200 samples per second. The MU can also access data from four serial digital channels and provide outputs on eight command channels. During pre-flight the commands can be ground initiated, and following launch they can be time event programmed as well as being programmed repetitive in either mode. The PCM rate is 1.6 Mbps and the MU stores five in-flight selectable formats in a 4096 words by 16 bits CMOS RAM memory. Each RU can access 28 analog and 8 discrete channels, and the RU can control two command and six verification channels. The PSV does not interface to the data bus; it is controlled via a MU or RU command channel. The system can be externally synchronized or operated from an internal clock with a graceful transfer to eliminate data loss. Small size, light weight, low power and high reliability are primary characteristics of the system. Built-in monitors and fully automated computer controlled test equipment provide rapid and extreme parameter testing with a high degree of fault isolation.

      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.

      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.

      Chang, Horen; Alvarez, Richard; Lee, Wilfred; Niwa, Kunihiko; Rieger, Frederic J.; Stanford Telecommunications, Inc.; International Telecommunications Satellite Organization; Comsat Laboratories (International Foundation for Telemetering, 1982-09)
      A prototype interference identification system has been developed to detect and identify interfering FDM-FM carriers originating within the INTELSAT* system. Interfering carriers are identified by distinctive code (signature) modulation of the energy-dispersal waveform of each FDM-FM carrier. Identification presently is accomplished within 10 minutes for ratios of interfering carrier power to noise power down to -2 dB, and for ratios of interfering carrier power to desired carrier power down to -17 dB. Possible improvements are discussed for more rapid identification.

      Chafin, Roy L.; Jet Propulsion Laboratory California Institute of Technology (International Foundation for Telemetering, 1982-09)
      There are several underlying factors in the design of an operations organization to control a high technology spacecraft tracking system. The first is the princple of differentiation and integration. The multitude of tasks must be divided so that each individual or team can accomplish assignments without being overloaded. Then, the efforts of all the elements in the organization must be integrated for a consistent attack on the problem of tracking a spacecraft. The differentiation tends to be primarily along technical or functional lines, and by time span, but there are other considerations. The integration is provided by the organization’s coordination and control elements. Operating positions can be designed to be procedurally operated, knowledge operated, or somewhere in-between. “Procedurally operated” means that the operator follows a strict procedure. He does not need to know how the system works, only which procedure to follow. A “knowledge based” operating position means that the operator understands the system sufficiently well to know what to do to accomplish a task. He does not need written procedures. The selection of either procedural based or knowledge based operations influences the operator skill level required, the organization design, and the support required. The system’s uncertainty level, stability level, and complexity are examined to evaluate the level of procedural operation possible.

      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.

      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.