GB1086212A - Vehicle identification system - Google Patents

Abstract

1,086,212. Track equipment. NATIONAL RESEARCH DEVELOPMENT CORPORATION. April 23, 1964 [April 23, 1963; May 10, 1963], Nos. 5922/63 and 18602/63. Heading B7N. [Also in Divisions G4-G6] A vehicle identification system uses modulated infrared light. In one embodiment the vehicle has position-coded reflectors, Fig. 2, and a static point has a semi-conductor diode lamp 3 energized from a generator 1. Phase-sensitive detector 9 rejects any received signals not having a predetermined phase relative to the output of generator 1. The vehicle may also be provided with another set of reflectors to provide timing pulses at the receiver. Fig. 5 shows an arrangement in which an array of reflectors 23 is provided on the vehicle and a corresponding array of detectors is provided at the receiver. The four corner reflectors provide a control pulse from gate 26 when the vehicle is correctly aligned with the receiver to pass the remaining pulses from the selectively reflected beams. In another embodiment the vehicle carries a lamp which is continuously energized by a code pulse generator. Each group of code pulses may be preceded by a start pulse at a different modulation frequency to enable the receiver at the correct instant. In Fig. 10 (not shown) an array of lamps is energized so that all lamps and only selected lamps are on alternately. This arrangement allows the receiver to block its output when one or more of the lamps fail.