Patent ID: 6088086
Filing Date: 2000-07-11
Classification: G01S

Abstract:
A method for operating a Scott-type scannerless imaging laser radar, said laser radar comprising a transmitted beam, a target, and a ranging receiver comprising a detector means having n pixels, modulation means comprising an image intensifier whose gain is controlled by an image intensifier control voltage, and a range processor, the method comprising:i) modulating the transmitted beam power periodically;ii) illuminating the target with the transmitted beam;iii) detecting a reflection of the transmitted beam from the target using the ranging receiver;iv) measuring a charge A.sub.n at each of the n pixels of the detector means of the ranging receiver integrated over an integral number of modulation cycles while the image intensifier control voltage is periodically modulated in phase with the transmitted beam;v) measuring a charge B.sub.n at each of the n pixels of the detector means of the ranging receiver integrated over an integral number of modulation cycles while the image intensifier control voltage is periodically modulated 90 degrees out of phase with the transmitted beam;vi) measuring a charge C.sub.n at each of the n pixels of the detector means of the ranging receiver integrated over an integral number of modulation cycles while the image intensifier control voltage is periodically modulated 180 degrees out of phase with the transmitted beam;vii) measuring a charge D.sub.n at each of the n pixels of the detector means of the ranging receiver integrated over an integral number of modulation cycles while the image intensifier control voltage is periodically modulated 270 degrees out of phase with the transmitted beam, and;viii) determining range to the target by extracting from the integrated charges A.sub.n, B.sub.n, C.sub.n, and D.sub.n a round trip phase shift .phi..sub.n for each of the n pixels of the detector means of the ranging receiver.