Abstract: A vehicle location system having a plurality of stationary wayside stations positioned at predetermined geographical locations. The passage of a vehicle near a station references the location of the vehicle at that point in time and automatically supplies the remote headquarters with updated information as to the whereabouts of all vehicles operating in the system. The system enables low power radio frequency signals to automatically communicate error free location information between the wayside station and the vehicle by maintaining the integrity of the signal. Automatic transmission to a remote headquarters of a precoded message such as an emergency communication can be initiated from either the vehicle or a portable transmitter. A common radio frequency channel may be used for transmittal of both audio and digitally encoded messages to and from a plurality of vehicles and a discriminator in each vehicle automatically selects and displays only those digital communications directed to it.

Abstract: A vehicle location system having a plurality of stationary wayside stations positioned at predetermined geographical locations. The passage of a vehicle near a station references the location of the vehicle at that point in time and automatically supplies the remote headquarters with updated information as to the whereabouts of all vehicles operating in the system. The system enables low power radio frequency signals to automatically communicate error free location information between the wayside station and the vehicle by maintaining the integrity of the signal. Automatic transmission to a remote headquarters of a precoded message such as an emergency communication can be initiated from either the vehicle or a portable transmitter. A common radio frequency channel may be used for transmittal of both audio and digitally encoded messages to and from a plurality of vehicles and a discriminator in each vehicle automatically selects and displays only those digital communications directed to it.