Two-Stage Laser Pointing System for Atmospheric Turbulence Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current laser pointing systems face challenges in achieving high precision, range, and stability while correcting atmospheric turbulence and tracking moving targets, requiring large servo bandwidths and high angular resolution, which is not adequately addressed by existing solutions.
Innovation Solution
An opto-mechanical architecture with a two-stage pointing system, including a coarse and fine pointing mechanism, utilizing passive and active imaging channels with synchronized high-speed cameras and power lasers, and a convergent optical device to correct atmospheric disturbances and ensure precise targeting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single-stage pointing system is used, then the system structure is simple, but the pointing precision and stability are insufficient for correcting atmospheric turbulence
Solution Approach 1:
The pointing system is divided into two independent stages: a coarse pointing stage with a first pointing device providing wide angular coverage, and a fine pointing stage with a second pointing device delivering microradian precision. This segmentation allows each stage to be optimized for its specific function, achieving high overall precision without requiring a single overly complex device.
Solution Approach 2:
The patent adds a temporal dimension to the pointing control by implementing sequential operation where the coarse pointing stage first acquires and tracks the target, then the fine pointing stage engages for precision correction. This two-stage temporal sequence resolves the contradiction by achieving high precision through staged refinement rather than a single complex simultaneous system.
2Reliability
If high servo bandwidth is used to track moving targets and correct atmospheric turbulence, then the tracking accuracy is improved, but the system complexity and cost increase significantly
Solution Approach 1:
The servo control is segmented into two bandwidth regimes: the coarse pointing stage handles low-frequency target motion and atmospheric drift, while the fine pointing stage provides high-bandwidth correction for rapid turbulence changes. This segmentation allows the high servo bandwidth requirement to be localized to only the fine pointing channel, reducing overall system complexity.
Solution Approach 2:
The active imaging channel serves as an intermediary that bridges the coarse and fine pointing stages. It provides real-time target position feedback that feeds into both stages, enabling coordinated control that achieves high tracking accuracy without requiring both stages to operate at maximum bandwidth simultaneously.
3Adaptability or versatility
If a single pointing device is used, then the device structure is simple, but the angular coverage and pointing precision cannot be achieved simultaneously
Solution Approach 1:
The pointing function is segmented across two devices: the first pointing device (coarse stage) is designed for wide angular coverage with large deflection capability, while the second pointing device (fine stage) is optimized for small angular corrections with high precision. This segmentation allows each device to be specialized for its operational range.
Solution Approach 2:
The patent merges the output of the coarse pointing stage with the fine pointing stage in a cascaded configuration. The coarse stage establishes the general pointing direction, and the fine stage refines it to the final precise position. This merging of two specialized devices achieves both wide coverage and high precision that neither device could achieve alone.
4Measurement precision
If active imaging is used to provide target position feedback, then the pointing accuracy is improved, but the system requires additional optical channels and complexity
Solution Approach 1:
The active imaging channel is designed to serve multiple functions: it provides target detection, tracks moving targets, measures atmospheric turbulence, and generates feedback for both coarse and fine pointing control. This multi-functionality reduces the need for separate dedicated sensors for each function, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The active imaging channel uses its own transmitted light (from the illumination source) to illuminate the target and capture reflected light for position measurement. This self-service approach eliminates the need for separate passive imaging systems or external illumination, reducing the number of additional optical channels required.
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
The system achieves high precision and stability in targeting moving objects over long ranges by dividing the pointing process into coarse and fine stages, allowing for effective correction of atmospheric disturbances and efficient tracking, while maintaining cost-effectiveness and modularity.
Implementation Method 1
Photons emitted by a laser and reflected by different objects in a scene are collected by an image receiver
Implementation Method 2
a laser source (17 1), also called the power channel (17)
Implementation Method 3
correction of the effects of atmospheric turbulence on the free propagation of laser beams
Implementation Method 4
a converging optical device equipped with focusing means
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention concerns an optical system for pointing a laser at a target (100) through the atmosphere, with four optical paths: - a passive imaging path with an auxiliary camera (1) linked to a coarse pointing control device (2), - an illumination path with a pulsed illumination source (5) and time-synchronisation means (11), said paths comprising a first shared coarse pointing optical device (4), - an effector path with a power laser source (171), - an active imaging path with: • a high-speed camera (101) synchronised with the illumination source (5) by the synchronisation means (11), and linked to a fine pointing control device (121), • means for harmonising the high-speed camera (101) with the power laser source (171), The active imaging and effector paths form a pair and comprise - a second shared coarse pointing optical device (141), the coarse pointing devices being controlled by the coarse pointing control device (2), a shared fine pointing optical device (161), controlled by the fine pointing control device (121), and the coarse pointing control device (2) is linked to the fine pointing control device (121).