Next Article in Journal
Joint Sparse and Low-Rank Multitask Learning with Laplacian-Like Regularization for Hyperspectral Classification
Previous Article in Journal
Modeling of Alpine Grassland Cover Based on Unmanned Aerial Vehicle Technology and Multi-Factor Methods: A Case Study in the East of Tibetan Plateau, China
Article Menu
Issue 2 (February) cover image

Export Article

Open AccessArticle

Coherent Auto-Calibration of APE and NsRCM under Fast Back-Projection Image Formation for Airborne SAR Imaging in Highly-Squint Angle

1
Tianjin Key Laboratory for Advanced Signal Processing, Civil Aviation University of China, Tianjin 300300, China
2
School of Electronic Information and Engineering, Nanchang University, Nanchang 330031, China
3
School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, S2-B3a-06, 639798, Singapore
4
National Key Lab for Radar Signal Processing, Xidian University, Xi’an 710071, China
*
Author to whom correspondence should be addressed.
Current address: College of Electronic Information and Automation, D-301, Civil Aviation University of China (South), No. 2898, Tianjin Jinbei Road, Dongli District, Tianjin 300300, China.
Remote Sens. 2018, 10(2), 321; https://doi.org/10.3390/rs10020321
Received: 9 January 2018 / Revised: 9 January 2018 / Accepted: 18 February 2018 / Published: 21 February 2018
  |  
PDF [4090 KB, uploaded 23 February 2018]
  |  

Abstract

Synthetic Aperture Radar (SAR) imaging with a non-zero (forward) squint angle is capable of providing a longer time for reaction than that of the broadside mode. However, due to the large squint angle, there will be severe coupling between range and azimuth samples in the echoed data, which is known as the problematic Range Cell Migration (RCM) in the SAR community. Especially when the SAR sensor mounted on an airborne platform encounters unexpected motion deviations/errors, the coupling becomes more complicated, and it is difficult to differentiate the systematic RCM for the SAR Image Formation Processing (IFP) and the non-systematic RCM error to be compensated. To this end, a novel and accurate SAR imaging algorithm is proposed in this paper to facilitate the processing of airborne SAR data collected at a high-squint angle. Firstly, the proposed algorithm is established under a Fast Time-Domain Back-Projection (FTDBP) framework for the SAR IFP. FTDBP paves the way to avoid the complicated processing for the systematic RCM as for the conventional SAR IFP in the Doppler processing manner. It is capable of generating a high-resolution SAR image efficiently under more general geometries and configurations. Secondly, regarding the non-systematic RCM errors, the proposed algorithm realizes the compensation by correcting both the Non-systematic Range Cell Migration (NsRCM), as well as Azimuthal Phase Error (APE) in a coherent manner. It is consequently capable of auto-calibrating the effects of the motion error completely without being dependent on the airborne navigation unit. Finally, both simulated and raw data collected by the airborne squinted SAR are applied to evaluate the proposed algorithm. Comparisons with conventional algorithms are carried out to reveal the superiority of the proposed algorithm. View Full-Text
Keywords: squint Synthetic Aperture Radar (SAR); auto-calibration; Fast Time-Domain Back-Projection (FTDBP); Azimuthal Phase Error (APE); Non-systematic Range Cell Migration (NsRCM) squint Synthetic Aperture Radar (SAR); auto-calibration; Fast Time-Domain Back-Projection (FTDBP); Azimuthal Phase Error (APE); Non-systematic Range Cell Migration (NsRCM)
Figures

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Yang, L.; Zhou, S.; Zhao, L.; Xing, M. Coherent Auto-Calibration of APE and NsRCM under Fast Back-Projection Image Formation for Airborne SAR Imaging in Highly-Squint Angle. Remote Sens. 2018, 10, 321.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Remote Sens. EISSN 2072-4292 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top