ABSTRACT
A CO(2) heterodyne lidar system and high speed digitizer were used to examine properties of returns from disk and belt-type calibration targets and atmospheric aerosols. Amplitude statistics of the returns from the targets examined corresponded to those of the Rayleigh phasor predicted by theory. Returns from a belt sander fluctuated at a much slower rate than those from the disks or aerosols, requiring longer averaging times for accurate power measurement. At very close focal lengths returns from single large particles often domier nated the backscattered aerosol signal.
ABSTRACT
We determine the backscatter reflectance (more properly the bidirectional reflectance distribution function at a 45 degrees angle of incidence and observation) for circularly polarized radiation of lambda = 10.6 microm for 120-grit aluminum oxide sandcloth (1.5 x 10(-2) sr(-1)) and 400-grit silicon carbide sandpaper (1.1 x 10(-2) sr(-1)) with respect to sublimed flowers of sulfur (1.8 x 10(-1) sr(-1)). The effect of range and the atmospheric effect of turbulence-induced beam wander are discussed for both rotating disks and linearly translated belts. The advantages of large slowly rotating disks for field calibrations are presented.
