Cloud penetration laser radar experiments

This paper describes the modification of an Air Force Research Labs laboratory at WPAFB to allow testing and verification of the impact of clouds on EO sensors. A cloud of particles seventy-five feet in length can be created and characterized, including particle size distributions, uniformity measurements and overall optical depth. At the output of the cloud tube a hemispherical scanner can direct the beam to either a 2-4 km test range or another laboratory for detailed measurements of the transmitted light. The detailed measurements include scattering profile measurements, polarization characterizations and temporal profiling which are all necessary to develop and verify theoretical models of system performance. A review of the cloud particle sizes and distributions that can be generated with the facility is presented. An evaluation comparing the generated clouds to the clouds typically encountered operationally is presented with an assessment of the facility limitations. The results from initial laser imaging experiments made at 1.54 microns with an InGaAs camera are presented and evaluated. A detailed overview of experiments planned for the future is given.