Atmospheric propagation effects on infrared radars

Compact coherent CO2 laser radars have the potential for greatly improved angle, range, and velocity resolution relative to their microwave radar counterparts. This research program was aimed at obtaining quantitative understanding of target reflection and atmospheric propagation effects on such laser radars through a combination of theory and experiments. Toward those ends, improved statistical signal models were developed, and corroborated through measurements, for turbulence and speckle effects in 2-D pulsed imager operation. Speckle and clutter effects in 2-D Doppler imager operation were also studied through analysis and measurements. Possible bad-weather laser radar operation, using scattered light, was considered theoretically, but shown to require use of a different laser wavelength than the 10.6 micron CO2 laser wavelength. A theoretical study of the use of high time-bandwidth (TW) product signal waveforms in 3-D imaging radar was also performed. The experimental portions of the research were carried out under a collaboration arrangement with the Opto-Radar Systems Group at MIT Lincoln Laboratory.