The purpose of the Navy-Wide Optical Signatures Program is to provide target signature, clutter background, and atmospheric data to Navy electro-optical programs (excluding laser systems). While the visible and ultraviolet spectral regions areincluded within the scope of this task, primary emphasis has been upon providing data for the infrared spectral region. The purpose of this paper is to discuss measurements, analysis, and simulation tasks which are being performed to provide an understanding of target/background/infrared system inter-relationships. Measurement tasks include air-to-air, air-to-ground, and ground-to-air operations with a variety of targets and background scenes using the following equipment: a. Airborne multispectral scanner, b. Radiometric imaging FLIR, c. Airborne measurement pod in conjunction with an AIM-9L seeker, and d. A variety of interferometers and infrared search sets. Analysis tasks include: a. Statistical analysis and modelling of background scenes, b. Spectral extrapolation, and c. Evaluation of simulation methods. Simulation tasks include: a. Development of an AIM-9L optics and reticle simulation, b. Development of fast storage/recall techniques for the background/reticle ensemble, c. Signal processing simulation and hardware interface, d. Multi-detector system simulation, and e. Validation. Each of the elements above is discussed in some detail with emphasis on the manner in which each relates to the overall task.