Estimate of Maximum Detection Range for FLIR from EOMET 95 Measurement Data

FLIR sensor maximum range predictions for operational use may be based on the intersection of apparent target contrast temperature difference (deltaT sub app) and sensor minimum resolvable (MRTD) or minimum detectable temperature difference (MDTD), each expressed as a function of range. Ranges obtained using the SEARAD code (MODTRAN modified for sea surface radiance) are compared with those based on Beer's Law with constant extinction coefficient. Physical and meteorological parameters for the common scenario were taken from the database of the EOMET95 measurements in Monterey Bay, with the research vessel POINT SUR as instrumented target and measurement platform. MRTD and MDTD functions were developed as functions of range for a generic Common Module FLIR using the Johnson Criterion for resolution with a parallelepiped geometry model of the POINT SUR. The Beer's Law results underestimate the SEARAD based ranges by approximately 50% for detection but less for classification and identification. Replacement of Beer's Law with MODTRAN computed transmittance reduces this discrepancy. SEARAD based modeled sea radiance and short range contrast temperature show unexpected variation with range.