Optically based position location system for an autonomous guided vehicle
 An optically based position location system, comprises multiple reflectors ositioned at known locations in an environment; a vehicle for traveling along a path in the environment; a first sensor for generating and detecting a collimated and polarized first light signal reflected from one of the reflectors, and for generating a first output signal in response to detecting the first light signal; a second sensor for generating and detecting a collimated and polarized second light signal reflected from the reflector reflecting the first light signal, and for generating a second output signal in response to detecting the second light signal; and a data processor which uses the first and second output signals for determining the distance between a reference coordinate on the vehicle and the reflector. 
The United States of America as represented by the Secretary of the Navy
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G01S
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Gary A. Hobart R. Rebecca S. Theresa T. John M.
Gilbreath Everett, Jr. Inderieden Tran Holland