Laser Spot Stabilization via Shared Optical Path Turbulence Compensation
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Solution Overview
Problem
High energy laser beams used for remote target destruction are affected by atmospheric turbulence, leading to deflection and power loss due to turbulent disturbances, which existing methods fail to adequately compensate for, especially in extended targets with non-homogeneous surface brightness and turbulence-induced noise.
Innovation Solution
A method and device that utilize an illumination beam to create a reference image of a target object, which is compared to a stored or prior image to generate a correction signal for an optical correction device in the high energy laser's path, allowing for turbulence estimation and compensation without complex wavefront sensors, using image warping techniques to account for changes and predict future interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional turbulence detection methods (guidestars, tip-tilt laser spots, adaptive optics) are used, then turbulence can be detected and compensated, but additional sensors and transmitters are required, increasing device complexity
Solution Approach 1:
The image acquisition device serves dual purposes: it captures images for target tracking and simultaneously detects turbulence effects on the laser beam path. By analyzing image degradation (blur, distortion) caused by turbulence, the system obtains turbulence information without requiring separate dedicated sensors, thus resolving the contradiction between reliable turbulence compensation and device complexity
Solution Approach 2:
The system uses its own imaging function to self-diagnose turbulence conditions. The image acquisition device monitors the quality of images of the target object, and degradation in image quality directly indicates turbulence affecting the laser path. This self-service approach eliminates the need for external turbulence detection equipment
2Ease of operation
If image processing methods (center of gravity measurement, four quadrant detector) are used for stabilization, then target tracking is achieved, but temporal variations in surface brightness are interpreted as virtual turbulent tip-tilt movement, producing detrimental noise
Solution Approach 1:
The patent segments the image analysis into multiple independent features: target position (for tracking), image quality metrics (for turbulence detection), and surface brightness distribution (monitored separately). By separating turbulence detection from target tracking functions and using different analysis methods for each, the system avoids misinterpreting brightness variations as turbulence, thus resolving the contradiction between ease of operation and measurement precision
Solution Approach 2:
Instead of using the entire image for both tracking and turbulence detection, the patent applies partial action by using specific image regions and specific image quality metrics. It monitors only relevant degradation parameters (blur, distortion) that indicate turbulence, while ignoring brightness variations that do not correlate with atmospheric turbulence, thereby eliminating false noise signals
3Power
If the high energy laser beam power is maximized on the target object, then destruction effectiveness is improved, but atmospheric turbulence causes the radiation spot to move around on the target, deteriorating the effect
Solution Approach 1:
The system implements continuous feedback by monitoring image quality degradation in real-time and using this information to adjust the laser beam direction dynamically. When turbulence causes spot displacement, the feedback loop detects image degradation and corrects the beam pointing through fast steering mirrors, maintaining both high power concentration and spot position stability on the target
Solution Approach 2:
The patent applies preliminary action by predicting turbulence effects based on current image quality metrics and proactively adjusting the laser beam direction before significant spot displacement occurs. This predictive compensation maintains radiation spot stability while allowing maximum power delivery to the target
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively stabilizes the radiation spot on the target object, maximizing laser energy delivery and reducing radiation time by compensating for turbulence effects without the need for additional sensors, thus enhancing the precision and efficiency of high energy laser applications.
Implementation Method 1
Radiation reflected by the target object that is illuminated by the illumination beam
Implementation Method 2
The propagation of high energy laser beams in the atmosphere is subject to turbulent disturbances that are caused by temperature fluctuations, and thus minor fluctuations in the refractive index of the air
Data Source
AI summary
A method for local stabilization of a radiation spot on a remote target object, where the radiation spot is formed by a high energy laser beam that is aimed at the target object by a high energy radiation emitter, the includes illuminating the target object is illuminated by an illumination beam that is aimed at the target object by an illumination device. The method also includes receiving, by an image acquisition device, radiation reflected by the target object that is illuminated by the illumination beam, where the radiation reflected by the target object to the image acquisition device passes through the same optical path as the high energy laser beam. An image processing is performed by analyzing and comparing an image of the illuminated target object or part of the illuminated target object acquired by the image acquisition device to at least one image of the illuminated target object or part of the illuminated target object produced at a prior point in time or to an image stored in an object database. And a correction signal is determined, based on the comparison, with which an optical correction device arranged in the optical path passed through by both the high energy laser beam and the reflected radiation is actuated.