State entry beacon system

• US 5,250,955 A
• Filed: 06/05/1992
• Issued: 10/05/1993
• Est. Priority Date: 06/05/1992
• Status: Expired due to Fees

• Current Assignee: Locheed Information Management Services Co.
• Original Assignee: Lockheed Information Services Company
• Inventors: Major, Harvey W., Beffa, James C., Butscher, Frank D., Beauchamp, Bruce A.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US07/894,700
• Time in Patent Office: 487 Days
• Field of Search: 342/457, 342/386, 342/398, 342/407, 342/408, 342/415, 364/449
• US Class Current: 342/457
• CPC Class Codes: G01S 1/68 Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information
• CPC Class Codes: G08G 1/096716 where the received information does not generate an automatic action on the vehicle control
• CPC Class Codes: G08G 1/096758 where no selection takes place on the transmitted or the received information
• CPC Class Codes: G08G 1/096783 where the origin of the information is a roadside individual element

Abstract

A beacon system wherein a beacon station is placed at a landmark such as a state line adjacent a major highway to broadcast information-containing alternating directional signals. In addition, each vehicle may be equipped with a radio receiver, a receiving decoder and a data analysis processor for receiving data signals from the beacon station. The beacon station includes an information encoder for generating first and second alternating but distinct location signals, first and second directional antennas disposed to radiate in opposite directions along the path of travel, the directional antennas having a significant back attenuation, a radio frequency transmitter for broadcasting the two location signals, preferably as data packets, to vehicle-mounted receivers along the path of travel, and an r.f. switcher for switching signal output of the transmitter between the two antennas in synchronization with the two location signals. The data analysis processor associated with each vehicle-carried receiver includes a half-circular buffer operative to capture a succession of packets received from the receiving decoder, to preserve initially-received complete packets of the first location signals and to preserve last-received complete packets of the second location signals. The data analysis processor further includes means for processing the preserved packets in the half-circular buffer to determine the exact crossover point of the landmark marked by location of the transmitter.

Claims

1. A beacon system for automatically marking and identifying a boundary landmark along a path of travel to a data gathering device in a moving vehicle, comprising:

a radio beacon station placed adjacent the boundary landmark for broadcasting as a first beacon signal a first location signal and as a second beacon signal a second location signal, said first and second location signals being transmitted from a single location on a single frequency alternately in opposite directions along a path of travel; and

a radio receiving means, said radio receiving means including a radio receiver for said single frequency and a data analysis means, said radio receiving means being disposed in the moving vehicle for receiving said first and second location signals from the beacon station as the vehicle approaches and passes the boundary landmark, said data analysis means including means for determining from reception of both the first location signal and the second location signal the point of passing of the boundary landmark.

2. A beacon system for automatically marking and identifying a boundary landmark along a path of travel to a data gathering device in a moving vehicle, comprising:

a radio beacon station placed adjacent the boundary landmark for broadcasting as a first beacon signal a first location signal and as a second beacon signal a second location signal, said first and second location signals being transmitted on a single frequency alternately in generally opposite directions along a path of travel, said beacon station including;

first and second directional antennas disposed to radiate in opposite directions along the path of travel, said directional antennas each having significant back attenuation;

a packet modulator means for generating said first and second location signals as data packets carrying alternately different digital information;

a radio frequency transmitter for broadcasting the first and second location signals as different data packets; and

an r.f. switcher for switching signal output of the transmitter between the first and second directional antennas in synchronization with the first and second location signals; and

a radio receiving means, said radio receiving means including a radio receiver for said single frequency and a data analysis means, said radio receiving means being disposed in the moving vehicle for receiving said first and second location signals from the beacon station as the vehicle approaches and passes the boundary landmark, said data analysis means including means for determining from reception of both the first location signal and the second location signal the point of passing of the boundary landmark.

3. The beacon system according to claim 2 wherein the receiving means includes:

a receiving packet demodulator coupled to said receiver; and

wherein said data analysis means is coupled to receive data from said receiving packet demodulator.

4. The beacon system according to claim 3 wherein said data analysis means comprises:

a data buffer means coupled said receiving demodulator for capturing a succession of packets received from said receiving packet demodulator, said data buffer means including means for preserving initially-received complete packets and for preserving last-received complete packets; and

means for processing said preserved packets from the data buffer to determine, from a first succession of stored first location signals and a second succession of stored second location signals, an exact point of passing of the boundary landmark as marked by location of the transmitter.

5. The beacon system according to claim 4 wherein the data analysis means further includes means for initiating the recording of a mileage reading for the moving vehicle upon determination of the exact point of passing the boundary landmark.

6. A beacon system for automatically marking and identifying a boundary landmark along a path of travel to a data gathering device in a moving vehicle, comprising:

a radio beacon station placed adjacent the boundary landmark for broadcasting as a first beacon signal a first location signal and as a second beacon signal a second location signal, said first and second location signals being transmitted on a single frequency alternately in opposite directions along a path of travel, said beacon station including directional antenna means having a first directionality and a second directionality disposed to broadcast in generally opposite directions along the path of travel, said directional antenna means having significant back attenuation with respect to said first and second directionality; and

a radio receiving means, said radio receiving means including a radio receiver for said single frequency and a data analysis means, said radio receiving means being disposed in the moving vehicle for receiving said first and second location signals from the beacon station as the vehicle approaches and passes the boundary landmark, said data analysis means including means for determining from reception of both the first location signal and the second location signal the point of passing of the boundary landmark.