Infrared transmission of data word from fixed station to mobile body

摘要

Directions to the mobiles (28, 31, 32) to follow selected routes (eg. 29) to their allotted parking spaces (30) are encoded in the data words from fixed transmitters (35-40). Each data words contains two directional bits characterising the course of the mobile addressed, a change-of-direction bit and at least one check digit. The change-of-direction bit serves to adapt the directional bits after changes of course. The infrared transmitters and receivers operate in accordance with pulse pause modulation, yielding advantages esp. for battery-powered transmitters backed up by solar cells.