product iamge

Aero-Optical Effects: Physics, Analysis and Mitigation

This document was uploaded by one of our users. The uploader already confirmed that they had the permission to publish it. If you are author/publisher or own the copyright of this documents, please report to us by using this DMCA report form.

Download
Search on Amazon

Simply click on the Download Book button.

Yes, Book downloads on Ebookily are 100% Free.

Sometimes the book is free on Amazon As well, so go ahead and hit "Search on Amazon"

AERO-OPTICAL EFFECTS

Explore the newest techniques and technologies used to mitigate the effects of air flow over airborne laser platforms

Aero-Optical Effects: Physics, Analysis and Mitigation delivers a detailed and insightful introduction to aero-optics and fully describes the current understanding of the physical causes of aero-optical effects from turbulent flows at different speeds. In addition to presenting a thorough discussion of instrumentation, data reduction, and data analysis, the authors examine various approaches to aero-optical effect mitigation using both flow control and adaptive optics approaches.

The book explores the sources, characteristics, measurement approaches, and mitigation means to reduce aero-optics wavefront error. It also examines the precise measurements of aero-optical effects and the instrumentation of aero-optics. Flow control for aero-optical applications is discussed, as are approaches like passive flow control, active and hybrid flow control, and closed-loop flow control.

Readers will benefit from discussions of the applications of aero-optics in relation to fields like directed energy and high-speed communications. Readers will also enjoy a wide variety of useful features and topics, including:

  • Comprehensive discussions of both aero-effects, which include the effects that air flow has over a beam director mounted on an aircraft, and aero-optics, which include atmospheric effects that degrade the ability of an airborne laser to focus a beam
  • A treatment of air buffeting and its effects on beam stabilization and jitter
  • An analysis of mitigating impediments to the use of high-quality laser beams from aircraft as weapons or communications systems
  • Adaptive optics compensation for aero-optical disturbances

Perfect for researchers, engineers, and scientists involved with laser weapon and beam control systems, Aero-Optical Effects: Physics, Analysis and Mitigation will also earn a place in the libraries of principal investigators in defense contract work and independent research and development.

Author(s): Stanislav Gordeyev, Eric Jumper, Matthew Whiteley
Series: Wiley Series in Pure and Applied Optics
Publisher: Wiley
Year: 2023

Language: English
Pages: 285
City: Hoboken

Aero-Optical Effects
Contents
Acknowledgements
1 Introduction
1.1 Motivation for Revisiting Aero-Optics
2 Fundamentals
2.1 Wavefronts and Index of Refraction
2.2 Huygens’ Principle
2.3 Basic Equations and Optical Path Difference
2.4 Linking Equation
2.5 Image at a Focal Plane (Far-field Propagation)
2.6 Far-field Intensity in the Presence of Near-field Distortions
2.6.1 Temporal Intensity Variation
2.7 Wavefront Components
3 Measuring Wavefronts
3.1 Interferometry Methods
3.2 Wavefront Curvature Methods
3.3 Gradient-based Wavefront Sensors
3.3.1 Shack-Hartmann Wavefront Sensor
3.3.1.1 Wavefront Reconstruction Algorithm
3.3.2 Malley Probe
3.3.3 SABT Sensor
3.4 Typical Optical Set-Ups
4 Data Reduction and Interpretation
4.1 Statistical Analysis
4.1.1 Temporal and Spatial OPDrms
4.1.2 Histograms and Higher-Moment Statistics
4.2 Spectral Analysis
4.2.1 Relation between the Deflection Angle Spectrum and the Wavefront Statistics
4.2.2 Dispersion Analysis
4.3 Modal Analysis
4.3.1 Zernike Functions
4.3.2 Proper Orthogonal Decomposition (POD)
4.3.2.1 Direct Method
4.3.2.2 Snapshot Method
4.3.3 Dynamic Mode Decomposition (DMD)
4.4 Cross-correlation-based Techniques
4.4.1 Local Convective Speeds
4.4.2 Multi-point Malley Probe Analysis
4.4.3 Spatially Varying 2-D Convective Velocity
5 Aperture Effects
6 Typical Aero-Optical Flows
6.1 Scaling Arguments
6.2 Free Shear Layers
6.2.1 Shear-Layer Physics
6.2.2 Aero-Optical Effects
6.2.3 Historical Shear Layer Measurements in AEDC
6.2.4 Weakly Compressible Model
6.3 Boundary Layers
6.3.1 Model of Aero-optical Distortions for Boundary Layers with Adiabatic Walls
6.3.2 Angular Dependence
6.3.3 Finite Aperture Effects
6.3.4 Nonadiabatic Wall Boundary Layers
6.3.5 Instantaneous Far-Field Intensity Drop-Outs
6.3.5.1 Absolute SR Threshold
6.3.5.2 Relative Intensity Variation
6.4 Turrets
6.4.1 AAOL
6.4.2 Flow Topology and Dynamics
6.4.3 Steady-lensing Effects at Forward-looking Angles
6.4.4 Aero-optical Environment at Back-looking Angles
6.4.5 Shock-effects at Transonic Speeds
7 Aero-Optical Jitter
7.1 Local and Global Jitter
7.1.1 Local Jitter
7.1.2 Global Jitter
7.2 Subaperture Effects
7.3 Techniques to Remove the Mechanically Induced Jitter
7.3.1 Cross-correlation Techniques
7.3.2 Large-Aperture Experiments
7.3.3 Stitching Method
8 Applications to Adaptive Optics
8.1 Beam-Control Components
8.2 How Much Correction Is Needed
8.3 Flow-Control Mitigation
8.3.1 Non-Flow-Control Mitigation
8.3.2 Some Qualities of Separated Shear Layers
8.3.3 Using the POD Analysis to Develop Requirements
8.4 Proper Number of Wavefront Sensor Subapertures to Actuator Ratio
8.4.1 Numerical Simulation
8.4.2 Simulation Results
8.4.3 Conclusion from the Simulation Results
9 Adaptive Optics for Aero-Optical Compensation
9.1 Analogies from Free-Stream Turbulence Compensation
9.1.1 Statistical Optics Theoretical Considerations
9.1.2 Power-Law Observations from Aero-Optical Wavefront Data
9.2 Compensation Scaling Laws for Aero-Optics
9.2.1 Adaptive Optics Control Law and Error Rejection Transfer Function
9.2.2 Asymptotic Results for Aero-Optics Compensation
9.2.3 Aero-Optics Compensation Frequency
9.2.4 Relation of Aero-Optics Scaling Laws to Free-Stream Turbulence
9.3 Spatial and Temporal Limitations of Adaptive Optics
9.3.1 Framework for Analysis of Aero-Optical Compensation
9.3.2 Deformable Mirror Fitting Error for Aero-Optical POD Modes
9.3.3 Decomposition of Correctable and Uncorrectable Power Spectrum
9.3.3.1 DM Sensitivity Transfer Function
9.3.4 Closed-Loop Residual Wavefront Error
9.3.5 Effect of Latency in Aero-Optics Compensation
9.4 Application to System Performance Modeling
9.4.1 Scaling of Aero-Optical Statistics to Flight Conditions
9.4.2 Joint Variations in Adaptive Optics Bandwidth and Actuator Density
9.4.3 Relative Impact of Aero-Optics with Other Propagation and System Effects
9.4.3.1 Comparing Aero-Optics to Free-Stream Turbulence Propagation
9.4.3.2 Comparing Aero-Optics to System Optical Jitter
9.4.4 Tracker Performance Degradations Related to Aero-Optics
9.4.4.1 Track Sensor Aero-Optical Imaging Resolution Degradation
9.4.4.2 Illuminator Propagation and Active Imaging through Aero-Optics
10 Concluding Remarks
References
Index
EULA