NDLI: Theory of data-driven SAR autofocus to compensate for refraction effects

Content Provider	IET Digital Library
Author	Garren, David Alan
Abstract	There are challenges in attempting to acquire sufficient atmospheric measurements that are required in order to model the physical atmospheric refraction effects for all transmission pulses within a typical synthetic aperture radar (SAR) collection interval. In particular, atmospheric turbulence can induce spatial variations of the air density, temperature, and other physical variables along the synthetic aperture, which can have differing effects on the local refraction-induced bending and delay of each of the transmission pulses. The primary goal of the current investigation is to develop an alternate approach based on data-driven techniques in order to develop methods for automatically correcting such refraction-induced defocus effects on SAR image data. This alternate methodology applies two-dimensional maximum likelihood signal-theoretic techniques in order to estimate and compensate for the refraction-induced phase errors of the input defocused SAR imagery, thus yielding improved scene refocus wherein the majority of the refraction-induced defocusing effects have been corrected. The efficacy of this data-driven approach is demonstrated through the injection of known bending and delay effects applied to measured Ku-band SAR data.
Starting Page	254
Ending Page	262
Page Count	9
ISSN	17518784
Volume Number	13
e-ISSN	17518792
Issue Number	Issue 2, Feb (2019)
Alternate Webpage(s)	https://digital-library.theiet.org/content/journals/iet-rsn/13/2
Alternate Webpage(s)	https://digital-library.theiet.org/content/journals/10.1049/iet-rsn.2018.5143
Journal	IET Radar, Sonar & Navigation
Publisher Date	2018-09-17
Access Restriction	Open
Rights Holder	© U.S. Government
Subject Keyword	Atmospheric Turbulence Data And Information; Acquisition, Processing, Storage And Dissemination in Geophysics Data-driven Approach Data-driven SAR Autofocus Data-driven Technique Geophysical Technique And Equipment Input Defocused SAR Imagery Instrumentation And Technique For Geophysical, Hydrospheric And Lower Atmosphere Research Ku-band SAR Data Local Refraction-induced Physical Atmospheric Refraction Effect Physical Variables Radar Equipment Radar Imaging Refraction-induced Defocus Effect Refraction-induced Defocusing Effect Refraction-induced Phase Error Remote Sensing by Radar SAR Image Data Sufficient Atmospheric Measurement Synthetic Aperture Radar Synthetic Aperture Radar Collection Interval System And Application Transmission Pulses Two-dimensional Maximum Likelihood Signal-theoretic Technique
Content Type	Text
Resource Type	Article
Subject	Electrical and Electronic Engineering

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1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
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9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

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