The design of laser radars and the determination of laser radar
signatures of various vehicles require accurate data on the reflectivity
of the target materials to far-field laser illumination at many different
wavelengths. Modeling software is required that will take the monostatic
reflectance data as input and combine this data with geometrical models
to develop a laser radar signature. Consideration of enhanced backscattering
can be critically important in developing laser radar signatures.
This is illustrated by the comparison of two signature models of the
same airplane—one developed using bidirectional reflectance measurement
data at 2 deg from the retrodirection, and the other developed from
monostatic measurement data at true retrodirection. When a reflecting
metal substrate is coated with a thin layer of weakly rough dielectric, as
is often the case with naturally occurring metal oxides on a parent metal
surface, a giant enhanced backscattering peak is observed that will further
enhance the lidar signature.