Vehicle locator

• US 3,940,630 A
• Filed: 10/21/1974
• Issued: 02/24/1976
• Est. Priority Date: 10/21/1974
• Status: Expired due to Term

• Current Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Original Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Inventors: Bergonz, Francis H.
• Primary Examiner(s): Lieberman, Eli
• Assistant Examiner(s): LaRoche, E. R.
• Application Number:
  US05/516,631
• Time in Patent Office: 491 Days
• Field of Search: 250/216, 250/566, 250/568, 250/271, 250/372, 250/222, 250/224, 340/23, 340/24, 340/32, 340/38 P, 340/50, 340/135, 340/47, 235/61.11 E, 356/51, 214/16.4 A
• US Class Current: 340/991
• CPC Class Codes: G01S 1/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 17/74 Systems using reradiation of electromagnetic waves other than radio waves, e.g. IFF, i.e. identification of friend or foe
• CPC Class Codes: G08G 1/20 Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles

Abstract

A system to locate selected vehicles traveling on standard streets or highways which periodically and automatically determines the location of the vehicle relative to a pre-established reference such as a map using fixed passive optical arrays as sign posts and means on the vehicles to read the sign posts and communicate the locational information thereon to a central monitoring station.

Claims

1. A system for locating at least one movable vehicle at predetermined locations comprising:

a plurality of reflective arrays, each array including a plurality of reflectors in a coded pattern and being located at a predetermined location adjacent a path for the vehicle along which the location of the vehicle is to be determined, each array having a predetermined start code;

a transmitter on the vehicle including means for producing at least one beam of radiant energy at ultraviolet frequencies, said transmitter beam having a vertically oriented fan shape which extends outwardly from the side of the vehicle to impinge and be reflected in accordance with said coded pattern by an array as the vehicle passes along the path; and

a receiver on the vehicle including detector means to detect said coded pattern of reflected radiant energy from an array, said detector means being positioned in a vertical plane with respect to said transmitter beam producing means and including optical means for focusing said reflected radiant energy, filter means which pass only said ultraviolet frequencies, a detector element to convert said filtered radiant energy into electrical signals, means positioned between said detector element and said array to restrict the view of said detector element to one reflector at a time, means connected to said detector means to sense said start code including means to accommodate a predetermined range of bit rates, means to store said array code upon being enabled by said start code sensing means, and means to transmit said array code which indicates the predetermined location of said vehicle.

2. The system defined in claim 1 wherein said means to sense said start code include an integrate and dump circuit to determine whether or not a reflector is being sensed.

3. The system defined in claim 1 wherein said transmitter includes second beam producing means which produce a second beam radiant energy which extends outwardly from said vehicle in a direction relative to the path opposite to said other beam to illuminate arrays which happen to be on the opposite side of the vehicle'"'"'s path and wherein said receiver includes second beam detecting means to detect said coded pattern of said second beam'"'"'s reflected radiant energy from an array.

4. The system defined in claim 1 wherein at least a main portion of said radiant energy has a wave length between 2486.5 and 2586.5 Angstroms.

5. The system defined in claim 1 wherein said array is divided into a predetermined number of sections positioned therealong, said sections having a predetermined length and some of said sections including retroreflectors to produce said coded pattern having predetermined reflection characteristics.

6. The system defined in claim 5 wherein each of said reflectors are retroreflectors comprised of a pair of cube corner reflector elements oriented at 180°

to each other and in vertical alignment, said cube corner reflector elements being coated with reflective material on the front surface thereof.