Research On Wavefront Tilt Correction Technology In Target Recognition And Tracking System

Optical tracking systems are widely used in the fields of high-resolution imaging and identification of targets,target testing and end-to-end guidance because of their high precision and high sensitivity.Target tracking algorithms combined with multi-stage composite axis tracking systems are mostly used in target identification and tracking systems to achieve target tracking.Single detector composite axis tracking technology is increasingly used in tracking systems due to the advantages of high optical energy utilization and simple structure.However,the single detector composite axis tracking system has problems such as difficult decoupling between channels and uncertain stability conditions,and the mainstream target tracking algorithm has the problem of template drift when the template is updated.To address these problems,the following work was carried out in this thesis.(1)To address the problem of template drift when the target tracking algorithm was updated,the sub-pixel template drift introduced by the template update was derived from the principle of the tracking algorithm.The feasibility of introducing the correction from the phase of the template frequency domain was deduced.The method of introducing corrections from the phase of the template frequency domain was proposed,which can add corrections with a small amount of computation and suppress the sub-pixel sampling errors introduced during template updates.The effectiveness of the template sub-pixel correction method is verified by experiments on motorized displacement table and VOT database experiments.(2)To address the problem of difficult decoupling between single detector composite axis tracking systems,a theoretical model of the tilt mirror was established to analyze its frequency response characteristics.A two-channel parallel control model was proposed for controlling the single-detector composite axis tracking system.A two-tilt mirror parallel correction system was designed on the 1.8-m telescope platform to replace the fine tracking subsystem in the composite axis tracking system to achieve the correction of the high-frequency tilt error of large travel.The results demonstrate that the two-tilt mirror parallel correction system can achieve similar effect of two-stage composite axis tracking and verify the feasibility of the control algorithm and structure.(3)For the problem of uncertain stability conditions of the single detector composite axis tracking system,a two-channel parallel control model was theoretically established.The stability of the two-tilt mirror parallel correction system was analyzed by approximating the Bode diagram.A typical system perturbation input model was established by analyzing the maneuvering performance of a typical target and the Kolmogorov turbulence spectrum synthesizing a typical wavefront tilt power spectrum.Combined with the tilt mirror frequency response model to determine the response of the two-tilt mirror parallel correction system to the typical input and the parameter determination method.Experiments were designed to validate the two-tilt mirror parallel correction system on the Gaomeigu 1.8-m telescope tracking platform.The results demonstrate that the stability of the two-tilt mirror parallel correction system is consistent with the model.