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Roadside beacon system

  • US 4,833,481 A
  • Filed: 07/20/1987
  • Issued: 05/23/1989
  • Est. Priority Date: 07/19/1986
  • Status: Expired due to Fees
First Claim
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1. A roadside beacon system in which a roadside antenna installed at a predetermined position in a road traffic network transmits data to a vehicle and receives data from a vehicle, comprising;

  • means for transmitting from said roadside antenna a first signal of constant amplitude, said first signal being modulated according to transmission data, and a second signal amplitude-modulated with a predetermined frequency, andnavigator means located on said vehicle for receiving signals transmitted from said roadside antenna, said navigator means including means for detecting said second signal to perform position detection and to output a position decision signal, and means for calibrating at least position data stored in said navigator means in response to said position decision signal and in accordance with data received via said first signal.

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