×

Vehicle location system

  • US 3,984,807 A
  • Filed: 11/05/1973
  • Issued: 10/05/1976
  • Est. Priority Date: 11/05/1973
  • Status: Expired due to Term
First Claim
Patent Images

1. A vehicle location system for providing a remote site with updated information regarding vehicle location wherein a plurality of stationary low power wayside radio transmitter stations respectively transmit digitally encoded location messages indicative of their respective geographical locations, said vehicles each carrying a radio receiver for receiving said coded message when said vehicle is in the proximity of said transmitter, and a radio transmitter for transmitting digitally encoded location messages to said remote site, wherein the improvement comprises:

  • means at each of said stationary wayside radio transmitter stations for accompanying said digitally encoded location messages with a first plurality of data bits preceding each digitally coded message and a second plurality of data bits following each digitally coded message, said first and second plurality of data bits encoding respectively different predetermined start and stop code patterns; and

    signal verifier means carried by each of said vehicles and coupled to said radio receiver carried by the vehicle which receives the encoded location messages from the wayside transmitter stations, said signal verifier means comprising the comparing start and stop code patterns with stored code formats permanently retained in said signal verifier means, the same code formats being permanently retained in each of said vehicles;

    said signal verifier means operatively coupled to said radio transmitter carried by the vehicle for inhibiting transmission of said digitally encoded location messages to said remote site unless the predetermined start and stop code patterns compare with said permanently retained code formats.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×