Analysis of an earth limb simulator for the aedc aerospace chambers 7V and 10V

摘要

Recent facility developments at the U.S. Air Force Arnold Engineering Development Center (AEDC) enable high fiedelity testing of both commercial and defense space-based infrared sensor systems and defense seeker systems. These two facilities, the 7V and 10V Aerospace Chambers, are cryogenic (to 20K), ultra-high vacuum test chambers. Both chambers are equipped with large-aperture, high-quality, all-0reflective metal optics collimating spectrally pure blackbody radiation sources. An earth limb simulator is provided as part of the overall test capability. This paper reports the pre-design analysis of a gradient background source made specifically for earth limb simulation. The gradient background source simulates the earth limb with a set of heated wires placed in a defocus position in the object space of the collimator in each chamber. Simulated irradiance in the out-of-focus image at the sensor focal plane array (FPA) is numerically obtained by two methods. Comparison of the expected irradiance at the FPA with the irradiance produced by the earth limb is also presented. Temperature, material composition, and physical dimensions of the constituent wires in the simulator are derived from the results of the analysis. CodeV~circleR is used extensively in the analysis effort.