The introduction of horizontal inhomogeneity of meteorological conditions in the EOSTAR propagation model

The effective field-of-view of an electro-optical sensor in a given meteorological scenario can be evaluated using a ray-tracer. The resulting ray trace diagram also provides information pertinent to the quality (distortion, mirages) of the image being viewed by the sensor. The EOSTAR (Electro Optical Signal Transmission And Ranging) model suite contains a ray tracer that has been upgraded to take into account horizontal inhomogeneities in the atmosphere, such as temperature gradients as observed in coastal areas where (e.g.) cold air flows out over warm waters. Initial results for horizontally inhomogeneous atmospheres are presented and compared to calculations for horizontally homogeneous atmospheres. It is shown that the horizontal inhomogeneity of temperature should be taken into account when assessing sensor performance.