High-resolution 3D coherent laser radar imaging

High range-resolution active imaging requires high-bandwidth transmitters and receivers. At Lockheed Martin Coherent Technologies (LMCT), we are developing both linear Frequency Modulated Continuous Wave (FMCW) and short pulse laser radar sensors to supply the needed bandwidth. FMCW waveforms are advantageous in many applications, since target returns can be optically demodulated, mitigating the need for high-speed detectors and receiver electronics, enabling the use of much lower bandwidth cameras. However, some of the penalties paid for these transceivers include a finite range search interval (RSI) and the requirement for slow chirp or long-duration waveforms, owing to the relatively slow sample frequency of the cameras used in the receiver. For applications requiring larger RSI's and short duration waveforms, LMCT is also developing high bandwidth pulsed ladar waveforms and receivers. This paper will include discussion of these two methods, their tradeoffs and sample imagery collected at LMCT.