Patent ID: 6580497
Filing Date: 2003-06-17
Classification: G01S,Y02A

Abstract:
A coherent laser radar apparatus comprising:as an optical component, a CW laser oscillating a laser radiation having a single wavelength; a dividing means for dividing laser radiation derived from said CW laser; an optical modulator for modulating one of said laser radiation divided by said dividing means; an optical antenna for projecting said modulated laser radiation as transmitted radiation toward a target, and also for receiving scattered radiation from the target as received radiation; combining means for combining the other of said laser radiation divided by said dividing means as local radiation with said received radiation; and a photodetector for optical-heterodyne-detecting said combined radiation and outputting a beat signal between said received radiation and said local radiation; and also comprising: as an electric component, a pseudo-random modulation signal generator for supplying a pseudo-random modulation signal to said optical modulator; a variable delay device for time-delaying a portion of the pseudo-random modulation signal generated from said pseudo-random modulation signal generator; a correlating device for multiplying the output signal of said photodetector by the pseudo-random modulation signal, time-delayed by said variable delay device; and signal processing means for acquiring physical information such as a distance of said target and a velocity of said target based upon a intensity and a frequency of the output signal from said correlating device, and also the delay time set by said variable delay device; wherein: an optical path between said optical components is constituted by an optical fiber.