EasyLaser is component-based laser system simulation software. Beam control system simulation is a main part of EasyLaser, which can be used for systems with multi-optical paths, multi-wavelength beams, and multi-controllers. A new numerical method about general kinematics separation is proposed for beam control system simulation. It provides axis rotation conversion relationships due to orientation data of apparatus of system, such as gimal, sensor and optical mirror. It gives their coupling and uncoupling matrixes in kinematics and controller model. The matrixes could change every iterative time automatically during the dynamic tracking process. The main advantage of the method is more suitable to solve the problems that the gimbal movement and geometry optical transmission are considered simultaneously. By using the method, sensor images and undershoot data are updated automatically. And further the kinematic driver or controller signals are separated automatically. Therefore the tracking and beam control can be designed without consideration of the system kinematical composition. Then the beam control system simulation has the virtues of generality, flexibility, and usability. No matter what kinds of gimbal and optical path, designer needs only to consider tracking and beam control aspects. In addition, a union beam control example for atmosphere transmission correction is given. It includes tracking tilt mirror and adaptive optics system. Simulation results show that the low-frequency fluctuation is restrained effectively and the high-frequency fluctuation is corrected obviously.
The image quality of space object or the Laser propagation characteristics in atmosphere will be degraded by the effect of turbulence. Adaptive optics can be used to correct atmospheric turbulent aberration, but the anisoplanatic effect of atmospheric turbulence is unavoidable. Adopting the special spectral filtering method, different type of anisoplanatism in different scene are systemically modelled, and the formulae that describing different type of anisoplanatic variance and their Zernike model components are obtained. According to HV turbulent outline, the characteristics of Zernike model components of different type of anisoplanatic variance are analyzed.
The simulation of the mean flow over airborne laser fairing as well as its aero-optic analysis is presented. The simulation reveals that the aero-optic effect with respect to the mean flow strongly depends on the beam direction, and the aberration is mainly low-order effect. The thickness of mean flow around the platform is defined and estimated based on aero-optical effect. A rough estimation formula about the thickness of flow field around the platform, the platform speed, and the characteristic time of the aero-optic effect, is brought about. The calculation results verify the reliability of the rough estimation formula.
Adaptive optics (AO) system can be used to detect and compensate the aberrational wavefront of beam in real time. The compensative ability will be affected by the detecting precision of wavefront. Noise is one of the most important factors that affect the detecting precision of Hartmann-Shack (HS) sensor. Noise can induce the errors of centroid detected by HS sensor, consequently influences the wavefront reconstruction. Based on the characteristic of Charge Coupled Devices (CCD), the model that simulates the detecting precision of wavefront affected by noise is built. Based on the factual application scene of artificial beacon, for typical HS sensor, the effects of noise on the detecting precision of wavefront are simulated, and the relations of wavefront beam spot in CCD, and the number of pixel used to calculate spot centroid are analyzed. Several results that can be used in engineering application are obtained.