Chhabra, Sorabh and Paul, Jyotirmay and Ramaprakash, Anamparambu N. and Surendran, Avinash (2021) Generalized approach to compensate for low- and high-frequency errors in fast Fourier transform-based phase screen simulations. Journal of Astronomical Telescopes, Instruments, and Systems, 7 (2). Art. No. 025007. ISSN 2329-4124. doi:10.1117/1.jatis.7.2.025007. https://resolver.caltech.edu/CaltechAUTHORS:20210629-180641573
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Abstract
Fast Fourier transform-based phase screen simulations give accurate results only when the screen size (G) is much larger than the outer scale parameter (L₀). Otherwise, they fall short in correctly predicting both the low and high frequency behaviors of turbulence-induced phase distortions. Subharmonic compensation is a commonly used technique that aids in low-frequency correction but does not solve the problem for all values of screen size to outer scale parameter ratios (G/L₀). A subharmonics-based approach will lead to unequal sampling or weights calculation for subharmonics addition at the low-frequency range and patch normalization factor. We have modified the subharmonics-based approach by introducing a Gaussian phase autocorrelation matrix that compensates for these shortfalls. We show that the maximum relative error in structure function with respect to theoretical value is as small as 0.5% to 3% for (G/L₀) ratio of 1/1000 even for screen sizes up to 100 m diameter.
| Item Type: | Article | |||||||||
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| Alternate Title: | A generalized approach to compensate for low and high frequency errors in FFT based phase screen simulations | |||||||||
| Additional Information: | © 2021 Society of Photo-Optical Instrumentation Engineers (SPIE). Paper 21012AS received Jan. 25, 2021; accepted for publication Jun. 1, 2021; published online Jun. 17, 2021. We would like to thank Sedmak for providing insights into the nature of atmospheric phase power spectrum through private communication. We also thank Xiang for sharing his MATLAB code that calculates the phase structure function quickly for a large number of phase screens. We acknowledge usage of IUCAA’s Pegasus cluster computer for running multiple independent iterations in parallel. | |||||||||
| Subject Keywords: | phase screen; fast Fourier transform; subharmonic; autocorrelation; phase structure function | |||||||||
| Issue or Number: | 2 | |||||||||
| DOI: | 10.1117/1.jatis.7.2.025007 | |||||||||
| Record Number: | CaltechAUTHORS:20210629-180641573 | |||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20210629-180641573 | |||||||||
| Official Citation: | Sorabh Chhabra, Jyotirmay Paul, Anamparambu N. Ramaprakash, and Avinash Surendran "Generalized approach to compensate for low- and high-frequency errors in fast Fourier transform-based phase screen simulations," Journal of Astronomical Telescopes, Instruments, and Systems 7(2), 025007 (17 June 2021). https://doi.org/10.1117/1.JATIS.7.2.025007 | |||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 109647 | |||||||||
| Collection: | CaltechAUTHORS | |||||||||
| Deposited By: | Tony Diaz | |||||||||
| Deposited On: | 29 Jun 2021 22:24 | |||||||||
| Last Modified: | 29 Jun 2021 22:24 |
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