BAE Systems presents the results of a program to model the performance of Raman LIDAR systems for the remote detection of atmospheric gases, air polluting hydrocarbons, chemical and
biological weapons, and other molecular species of interest. Our model, which integrates remote Raman spectroscopy, 2D and 3D LADAR, and USAF atmospheric propagation codes permits
accurate determination of the performance of a Raman LIDAR system. The very high predictive performance accuracy of our model is due to the very accurate calculation of the differential
scattering cross section for the specie of interest at user selected wavelengths. We show excellent correlation of our calculated cross section data, used in our model, with experimental data
obtained from both laboratory measurements and the published literature. In addition, the use of standard USAF atmospheric models provides very accurate determination of the atmospheric
extinction at both the excitation and Raman shifted wavelengths.
BAE SYSTEMS has developed a high-resolution 2D imaging laser radar (LADAR) system that
has proven its ability to detect and identify hard targets in occluded environments, through
battlefield obscurants, and through naturally occurring image-degrading atmospheres.
Limitations of passive infrared imaging for target identification using medium wavelength
infrared (MWIR) and long wavelength infrared (LWIR) atmospheric windows are well known.
Of particular concern is that as wavelength is increased the aperture must be increased to
maintain resolution, hence, driving apertures to be very larger for long-range identification;
impractical because of size, weight, and optics cost. Conversely, at smaller apertures and with
large f-numbers images may become photon starved with long integration times. Here, images
are most susceptible to distortion from atmospheric turbulence, platform vibration, or both.
Additionally, long-range identification using passive thermal imaging is clutter limited arising
from objects in close proximity to the target object.