Several different design problems and approaches are presented in this chapter to bring together the concepts that have been presented thus far. The problems are necessarily brief and incomplete, but they show the approach and some of the tradeoffs.
Infrared system design is not a process of synthesis. Rather it is a process of invention, analysis, and iteration. The process I have found to be most productive is to analyze first the geometryâcalculate the field of regard, the field of view, and the pixel size. Next calculate the time lineâthe frame time, dwell time, and the bandwidth. Then calculate the sensitivity on the idealized basis described above. The last step is the optical scheming. If all of this goes well (and it probably won't the first time) then repeat the sensitivity calculation with more accuracy and realism and do some real optical design.
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