• International Telemetering Conference Proceedings, Volume 11 (1975)

      International Foundation for Telemetering, 1975-10
    • Low Data Rates Necessary for RPV Command Guidance

      McIntyre, G. W.; Spencer, B. M.; Sperry Univac (International Foundation for Telemetering, 1975-10)
      In the design of a tactical multi-remotely piloted vehicle (RPV) data link, the RPV data rate and update rate are crucial to the multi-RPV scenario. Data rates on the order of 150 bits per second per RPV or fewer and update rates of fewer than 2 per second per RPV must be used if the RPV's are to operate successfully in a hostile jamming environment. This limit is imposed by the amount of RF spectrum that can be obtained for applying spread-spectrum to protect the data channel. Through data management all necessary RPV command and telemetry functions can be handled at these rates.
    • In-Bore Measurement of Projectile Acceleration and Base Pressure Using an S-Band Telemetry System

      Evans, James W.; Aberdeen Proving Ground (International Foundation for Telemetering, 1975-10)
      This paper presents the results of the instrumentation used on a firing test for making inbore measurements of projectile acceleration and base pressure. The system components; including the telemetry data link, acceleration and pressure sensors; and the packaging techniques are described. The data from a test of six 105mm proof projectiles fired in an M-68 tank gun are presented and compared with independent measurements.
    • Detectors Based on Conditional Tests

      Kassam, Saleem A; Thomas, John B.; Princeton University (International Foundation for Telemetering, 1975-10)
      The detection of a known signal in additive noise is an important function in many receivers. Nonparametric detectors, such as the sign detector, will result in systems with a constant false alarm rate, but usually suffer from a lower power compared to optimum parametric detectors. In this paper a conditional statistical test is used to obtain nonparametric detectors more powerful but still almost as simple to implement as the sign detector. The technique of conditional testing is therefore useful in obtaining improved detectors for practical use.
    • System Alternatives for the Public Service Satellite Consortium

      Janky, James M.; Potter, James G.; Lusignan, Bruce B.; The Federation of Rocky Mountain States, Inc.; Stanford University- (International Foundation for Telemetering, 1975-10)
      The purpose of the Public Service Satellite Consortium is to foster the shared use of satellites as a distribution mechanism for social services in health and education for public and private non-profit users. The utility of a consortium lies in its ability to aggregate a large number of small, diverse users into a market group which can then share the costs for the space segment and take advantage of the economies of scale in procurement of ground equipment. A summary of the technical analysis of the alternatives for both the space and ground segment equipments is presented, along with cost estimates. The recommended configuration consists of 20-watt transponders and on the ground, eight- to fifteen-foot diameter antennas, using parametric amplifiers. The capital cost for the electronics alone for a Community Antenna is under $9,500 in quantities of 1000 units. This low relative cost makes it possible for many new users to benefit from satellite technology.
    • RCC Telemetry Standards: Where Do We Go from 1975?

      Reynolds, R. Stanton (International Foundation for Telemetering, 1975-10)
    • Communications and Data Handling for the GSFC Modular Spacecraft

      Trevathan, Charles; GSFC Spacecraft Data Management Branch (International Foundation for Telemetering, 1975-10)
    • A Review of RPV Programs in the USAF

      Palmer, John A.; US. Air Force (International Foundation for Telemetering, 1975-10)
      A brief explanation of the background behind development and employment of operational RPV systems will be followed by a resume of their accomplishments and shortcomings. Reconnaissance, electronic warfare and strike systems will be covered. The main portion of the paper will discuss systems under development to support specific missions or improve RPV capabilities in general. The Compass Cope high altitude RPV, multi-mission RPVs, expendable drones, and mini-PPVs will be considered as a family of vehicles desianed to support a variety of mission requirements. In addition, programs to improve capabilities for launch, recovery, controls and sensor integration will be included. The overall emphasis is on an appreciation for the purpose and direction of the Air Force RPV development program.
    • Some Characteristics of the International Space Channel

      Noack, T. L.; Poland, W. B., Jr.; University of Missouri-Rolla; NASA (International Foundation for Telemetering, 1975-10)
      Some physical characteristics of radio transmission links and the technology of PCM modulation combine with the Radio Regulations of the International Telecommunications Union to define a communications channel having a determinable channel capacity, error rate, and sensitivity to interference. These characteristics and the corresponding limitations on EIRP, power flux density, and power spectral density for space service applications are described. The ITU regulations create a critical height of 1027 km where some parameters of the limitation rules change. The nature of restraints on power spectral density are discussed and an approach to a standardized representation of Necessary Bandwidth for the Space Services is described. It is shown that, given the PFD (power flux density) and PSD (power spectral density) limitations of radio regulations, the channel performance is determined by the ratio of effective receiving antenna aperture to system noise temperature. Based on this approach, the method for a quantitative trade-off between spectrum spreading and system performance is presented. Finally, the effects of radio frequency interference between standard systems is analyzed.
    • A Telemetry Link for an Earth Penetrator

      Caffey, Thurlow W. H.; Sandia Laboratories (International Foundation for Telemetering, 1975-10)
      The design and field-testing of a telemetry link to send signals to the surface of the earth from an earth penetrator are described. The link uses a PCM/FM format at a frequency of 10.5 kHz, dissipates 8 watts, and fits within a cylinder with an inside diameter of 100 mm. A bit error rate of less than 10⁻⁵ was achieved from a depth of 52 meters at a bit rate of 10³ bits per second.
    • The Mars Penetrator Telemetry and Control System

      Bentley, R. D.; Campbell, A. B.; Sandia Laboratories (International Foundation for Telemetering, 1975-10)
      A new method for exploring the planet Mars has been proposed* that will use ground-penetrating vehicles to carry scientific instruments below the Martian surface. The subsurface performance of various sequences of complicated experiments poses challenges in the design of the telemetry and control links. This article describes the overall mission, the penetrator, the constraints imposed by the mission and the penetrator, and a design for the telemetry/control system. This design uses a microprogrammed microprocessor; the sequences of commands are stored in a Read-Only-Memory (ROM), and a particular sequence is initiated by transmitting from the Earth the address in the ROM that contains the first of the commands for the specific sequence to be performed. Data from the experiments are stored in a memory for later transmission to an orbiter that serves as a relay station for the command and data links with Earth.
    • Prospect for International Standardization

      Henriques, Vico E. (International Foundation for Telemetering, 1975-10)
      The prospects for international standardization depend largely on activities of a number of official and semi-official international programs for standards. Many of the national standards developed by the technologically advanced countries are proposed for international standardization and the process of compromise and modification is necessary to make specific standards acceptable on a broad basis. A second area of dialogue is necessary for education so that the parties to a standardization effort are capable of talking at the same level of technological detail. And, thirdly, the specific types of standards that are needed fall into areas which range from easily quantifiable to agreements on communication and national standardization are on a continuum which ranges from technical refinement to preliminary discussion and candidate standard identification.
    • Expectations for the Radio Spectrum Available to the Space Services

      Jansky, Donald (International Foundation for Telemetering, 1975-10)
    • Summary: The NASA Low Cost Program

      Richards, Leo; NASA Headquarters Low Cost Systems Office (International Foundation for Telemetering, 1975-10)
    • Tape Tracking and Handling for Magnetic Tape Recorders

      Paroby, Walter; DiSilvestre, Raymond; NASA, Goddard Space Flight Center (International Foundation for Telemetering, 1975-10)
      One of the critical performance and life limiting elements of a spacecraft tape recorder instrumentation system which has received little attention in technical literature is magnetic tape tracking and handling technology. This technology is required to understand how to gently transfer tape from one reel to another with proper alignment and a desirable uniform velocity at the read and write transducer heads. The increased demand for high data rate (i.e. multi-track spacecraft recording instrumentation systems), coupled with performance under extreme environmental conditions, requires a thorough knowledge of the various parameters which establish an optimum designed tape tracking and handling system. Stress analysis techniques are required to evaluate these parameters substantiated with test tape tracking data, to show the effect of each parameter on a tape recorder instrumentation tracking system. The technology is applicable to ground type tape recorders where the detrimental effects of edge guidance can be eliminated.
    • Telemetry Applications in Wildland Fire Control

      Warren, John R.; Forest Service, USDA (International Foundation for Telemetering, 1975-10)
      Telemetry will be coming into wider use in wildland fire control because it provides the real-time information needed in decision-making. Two applications are described: transmission of airborne infrared imagery of the fire scene, and the relaying of meteorological data from remote stations. Experimental systems using these types of telemetered data are being developed at the USDA Forest Service's Pacific Southwest Forest and Range Experiment Station. Also under development are computerized models using telemetered and other information for predicting fire behavior.
    • Telecommunications, Health and Education

      Christenson, Ralph P.; Mountain States Health Corp. (International Foundation for Telemetering, 1975-10)
      Prior to 1971 there were many experiments conducted in order to demonstrate or test the feasibility, acceptance and effectiveness of communications technology applied to health care and education systems. Within the past year two groups of experiments were completed. One, utilizing terrestrial broad band systems, included seven separate applications. The other, which utilized the National Aeronautics and Space Administration's Applications Technology Satellite Six (ATS-6), had five experiments in health care and education. Each of these experiments is briefly described. Further experimentation is needed with special emphasis being given to the impact of technology on human systems. There is growing acceptance of the fact that demonstrations of feasibility are no longer needed. This particular session is concerned with "Telemetry for the Benefit of Mankind." I will assume that telecommunications is not excluded and that I can spend my time in describing some of the applications of communications technology to health care delivery and health education. I will not attempt to include all applications but will limit my attention to those that seem most timely and effective. Since all applications that will be mentioned were experimental in nature, concerned largely with feasibility and effectiveness, cost-benefits were incidental considerations.
    • Command and Data System for an Undersea Dredge

      Linders, Thomas E.; Lockheed Missiles & Space Co. (International Foundation for Telemetering, 1975-10)
      By the use of commercial equipment whose original purpose was to provide alarm monitoring (fire and burglar) over telephone lines, a command and data system was constructed to control an undersea dredge. The system was designed around the Larse Corporation Data Communicators (trademark), and only a PAM multiplexer and a digital demultiplexer were added to make the system perform. The system requirements were analyzed, and only after the candidate design was agreed upon were the ideas put to paper. The system was designed in modules, with the various components grouped according to their function, to simplify interconnecting and test/checkout. The system has performed well, no component failures have occurred to date, and all data and command functions have worked as expected.
    • The Influence of an Ambient Magnetic Field on Magnetic Tape Recorders

      Jorgensen, Finn; TRW Systems (International Foundation for Telemetering, 1975-10)
      Magnetic recorders are susceptible to external magnetic fields and hence prone to data degradation. This is primarily observed in instrumentation (space and ground) and computer recorders, where little or no shielding of the heads is provided. The magnetic core material in the heads attracts flux lines and will with certain orientations concentrate these in the record, play back or erase gaps. During recordings a foreign field may therefore be superimposed on the intended recording field and may cause errors in the form of phase shift and dc offset; these affects are agravated when AC bias is used in the recording process. If an external field is present during playback only, partial or complete erasure may take place. One external field is always present: The earth s magnetic field which has a magnitude of roughly one Gauss (or Oersted). The writer is not aware of any errors per se caused by this field, but it has numerous times caused difficulties in achieving a perfect demagnetization of heads (An oscillating and simultaneously decreasing field from a degausser does then in essence record a permanent magnetization into the heads, which in turn will result in noisy and distorted recordings). Other fields are man made, such as originating from heavy currents in cable harnesses. The analysis presented in this paper was undertaken to establish susceptibility limits for a field generated by a magnetic attitude control system for spacecrafts. This is illustrated in Figure 1, where three orthogonal electromagnets on board a spacecraft generate a magnetic moment (M), variable in magnitude and orientation. The attitude correcting torque (T) on the spacecraft is expressed as the cross product between this moment and the earth's field. Recording equipment may be located within a few feet of the center of the attitude control field, which must be limited in magnitude or the recorder shielded to avoid data errors and/or erasure.
    • Surface Acoustic Wave Devices for Communications

      Webb, D. C.; Naval Research Laboratory (International Foundation for Telemetering, 1975-10)
      Many surface acoustic wave (SAW) devices are now sufficiently well-developed that they can have a significant impact on systems design. This paper reviews the properties and limitations of SAW devices which seem particularly well suited to communications. The simple bandpass filter is considered in detail as it will undoubtedly see the widest usage of all SAW devices. The application of SAW analog matched filters in phase-shift-keyed synchronization and data demodulation is also discussed. Finally, SAW resonators and oscillators are briefly considered. A number of examples are included which show how system performance can be improved through use of SAW technology.