An obstacle detection system comprised of transmitters and collocated receivers spaced alongside railroad tracks and scanning across the tracks to a continuous retroreflective fence was studied, tested, and demonstrated. The transmitters emit a very narrow beam of collimated coherent light from a galium arsenide laser. The retroreflector establishes a narrow region with reflectivity substantially higher than the normal surroundings. An object located between the laser transmitter and the retroreflector will prevent the laser beam from impinging upon the retroreflector and will, therefore, cause a variation in the return energy normally observed by the receiver. This variation is then reported to a central control station for further action. An engineering model of a laser scanner was designed and built. In combination with an engineering model of a retroreflective fence, the scanner engineering model was used to successfully demonstrate the feasibility of the system concepts. (Author)

  • Corporate Authors:

    Radio Corporation of America

  • Publication Date: 1969-3-15

Media Info

  • Pagination: 162 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00039123
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: Final Rpt
  • Contract Numbers: DT-7-35509
  • Files: TRIS
  • Created Date: Nov 24 1973 12:00AM