• Measurement and Analysis of Urban Radio Channels for Communication System Design

      Frasco, L. A.; Goldfein, H. D.; U.S. Department of Transportation (International Foundation for Telemetering, 1971-09)
      This paper outlines a program to measure VHF and UHF urban radio channels for playback and analysis in the laboratory. These measurements are required for the design of high data rate communication equipment which makes efficient use of the radio spectrum. We include in this category data communication and surveillance equipment necessary to meet the demands of the variety of command and control functions envisioned for transportation systems by federal, state, and local governments. Included in the paper is a qualitative description of the channel followed by a discussion of the measurement techniques and hardware that will be used. The goal of the measurement program is to develop both analytic and experimental tools for the design and evaluation of advanced communication techniques specialized for signalling over the urban radio channel. These techniques will include modulation waveform design, coding, and the design of receiver structures including those which adapt to measured channel behavior. Future technology will permit complex hardware designs to be used in the implementation of these techniques while maintaining low system cost. The same techniques and approach used here for the urban channel can be applied to other radio channels that occur in transportation systems. In particular, they are applicable to data links for air-ground and high speed ground transportation system uses.
    • Microwave Crash Sensor for Automobiles

      Holmstrom, F. R.; Hopkins, J. B.; Newfell, T.; White, E.; U.S. Department of Transportation; Lowell Technological Institute (International Foundation for Telemetering, 1971-09)
      A prototype microwave radar anticipatory crash sensor for automotive applications is described. This system is for prospective use in conjunction with passive occupant restraints--protective devices that require no action on the part of the occupant to insure their effectiveness. Appropriate antenna configuration and circuitry permit position, velocity, and size discrimination of the target in a simple manner. Results of field tests are discussed, including the manner in which system parameters and target characteristics relate to the tradeoff between false alarm rate, miss rate, and system complexity.
    • Telemetry Applications in Grade Crossing Protection

      Hopkins, John B.; U.S. Department of Transportation (International Foundation for Telemetering, 1971-09)