Patent ID: 8275572
Filing Date: 2012-09-25
Classification: F41H,G01S

Abstract:
1. An apparatus comprising: a transmitter system configured to transmit a first collimated beam having a first frequency and a second collimated beam having a second frequency; a receiver system configured to detect a delayed difference frequency signal substantially equal to a difference between the first frequency and the second frequency, wherein the delayed difference frequency signal is generated by an object having non-linear electrical characteristics in response to the object receiving the first collimated beam and the second collimated beam; and a processor unit connected to the transmitter system and the receiver system, wherein the processor unit is configured to control the transmitter system and the receiver system to change at least one of the first frequency and the second frequency through a range of frequencies over time during transmission of the first collimated beam and the second collimated beam; compare the delayed difference frequency signal with an undelayed difference frequency signal substantially equal to the difference between the first frequency and the second frequency to form a comparison, and generate a range measurement for the object from the comparison.