Hardware and software developments for a closed-loop infrared mission simulation test capability

The Arnold Engineering Development Center (AEDC) scene generation test capability (SGTC) program has completed the development of a laser based direct write scene generation (DWSG) facility that provides dynamic mission simulation testing for infrared (IR) focal plane arrays (FPAs) and their associated signal processing electronics. The AEDC DWSG focal plane array test capability (FPATC) includes lasers operating at 0.514, 1.06, 5.4, or 10.6 micrometer, and acousto-optic deflectors (AODs) which modulate the laser beam position and amplitude. Complex radio frequency (rf) electronics controls each AOD by providing multi-frequency inputs. These inputs produce a highly accurate and independent multi-beam deflection or 'rake,' that is swept across the FPA sensor under test. Each rf amplitude input to an AOD translates into an accurate and independent beam intensity in the rake. Issues such as scene fidelity, sensor frame rates, scenario length, and real-time laser beam position adjustments require rf control electronics that employs the use of advanced analog and digital signal processing techniques and designs. By implementing flexible system architectures in the electronics, the overall capability of the DWSG to adapt to emerging test requirement is greatly enhanced. Presented in this paper is an overview of the signal processing methodology and designs required to handle the DWSG requirement. Further, the paper summarizes the current status of recent AEDC technology efforts tasked with the implementation of real-time and closed-loop scene manipulation including sensor optical simulation using the DWSG. The paper describes a proof-of-principle (PoP) demonstration which used high speed digital signal processors inherent in the DWSG electronic design to compute the rotation, translation, optical transfer function convolution, and system calibration functions during scene projection.