Patent ID: 7345744

Claim:
A ladar system comprising; a laser transmitter for generating a first laser signal; optics for receiving a second signal that is a reflected version of said first laser signal; an optical delay line adapted to generate a third signal from said first laser signal, wherein said third signal is a delayed version of said first laser signal, said third signal being delayed by a time T D that reduces a relative time difference between said second and third signals such that phase errors are less than a predetermined level, said time T D being approximately equal to a round trip time T R of said second signal; a mechanism for mixing said third signal with said second signal; a first detector adapted to detect said second signal mixed with said third signal and output a first output signal; a beam splitter for generating a fourth signal from said first signal; a second detector adapted to detect said third signal mixed with said fourth signal and output a second output signal; a first waveform modulator adapted to modulate said first signal, said first waveform modulator being adapted to generate a first linear frequency modulated chirp waveform; and a second waveform modulator adapted to modulate said fourth signal, said second waveform modulator being adapted to generate a second liner frequency modulated chirp waveform, said second chirp waveform being delayed by a time T 1 approximately equal to said time round trip time T R to provide an error signal; and a processor for using said error signal to provide a corrected output signal.