Particle size distribution measurements for transmission path applications

摘要

Performance simulation and testing of weapons-based electro-optical sensors in the atmosphere often requires that naturally occurring and countermeasure aerosol particle size distributions be measured. Particle size distributions are necessary inputs for models used to predict the attenuation and scatter of radiation between the sensor and target. Current atmospheric measurement methods use optical individual particle counters or cascade impactors to sample a relatively small volume of air and to count or sort, by, equivalent scatter size or aerodynamic mass, aerosol particles. Particle measurement instrumentation is needed that is more cost-effective and more nearly reflects the particle size distribution along the entire propagation path of the sensor. The purpose of this paper is to describe a method for determining particle size distribution parameters from multispectral transmission measurements made along the line o1 sight of an electro-optical sensor under test. The limitations and errors associated with particle size distribution point sampling for atmospheric propagation paths are discussed and compared with those obtained from integrated path measurements. An algorithmic inversion of transmittance data to obtain particle size distributions, its limitations and capabilities is described. Example data inversion results are shown, and the application of the technique to the measurement to environmental air quality is discussed