Conformal phased array aero-optical modeling and compensation

Abstract

The effect of subsonic turbulent boundary layer aero-optical disturbances on a conformal phased array for laser beam projection operating on a high-speed aircraft is considered. We employ a basic model for subsonic boundary layer disturbances developed by Cress et al. which is governed by the displacement thickness δ Ã to bound the magnitude of the problem, to determine the basic phenomenology affecting phased array performance, and to quantify requirements for compensation of these disturbances in the array subapertures. We used δ Ã ¼ 15 mm as a baseline value in quantifying phased array effects on a 7-aperture hexagonal array with 10 cm subapertures. Boundary layer piston and tilt disturbances dominate array effects, but higher-order disturbances are similar in magnitude to the differential piston over the array and 2× greater in magnitude than an upper bound on free-stream turbulence. Adaptive optics compensation of turbulent boundary layer disturbances in such a phased array requires error rejection bandwidths >1 kHz for high-fidelity array performance. Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 05/15/2015 Terms of Use: http://spiedl.org/terms Optical Engineering 071409-2 July 2013/Vol. 52(7) Whiteley and Gordeyev: Conformal phased array aero-optical modeling. . . Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 05/15/2015 Terms of Use: http://spiedl.org/terms

Ghost Imaging Through a Supersonic Wind‐Induced Environment Under Weak Illumination

“…The randomness of the airflow depends on the wind velocity, and beams propagation are severely affected under the airflow environment. [20][21][22] For GI under wind-induced environment, the propagation of random source is influenced by the random airflow, and the imaging quality is degraded due to additional noise to detected signal. [23] In addition, the detected optical signal is very weak under airborne condition because of long-distance imaging, and the imaging quality is influenced by both the airflow and detector noise, as a result, investigation on GI through a random environment induced by wind under low light detection is significant for applications in airborne remote sensing.…”

The Combined Effect of Jet and Atmospheric Turbulence on the Propagation of Airborne Partially Coherent Array Beams

“…[34][35][36][37] Since these excellent characteristics, partially coherent array beam is preferred for airborne laser systems in practical applications. [38,39] However, as mentioned above, the propagation properties of array beam located on the airborne platform could be influenced by the jet engine turbulence and atmospheric turbulence over long distance. Meanwhile, small-scale random of refractive index can significantly affect the performance of atmospheric remote sensing systems.…”

Propagation Properties of Gaussian Schell-Model Beam Array in the Jet Engine Exhaust Induced Turbulence

“…Furthermore, With the development of the array beam in space optical communication applications, the array beam systems are gradually used on the airborne platform. Recently, Whiteley et al investigated the effect of aero-optical disturbances on a conformal phased beam array located on the high-speed aircraft [39]. To the best of our knowledge, the effects of the jet engine turbulence on a GSM beam array have not been reported yet.…”