Joint image formation and two-dimensional autofocusing for synthetic aperture radar data

JOURNAL OF COMPUTATIONAL PHYSICS

卷:374

Article

Scarnati, Theresa^1,2  Gelb, Anne³ 

[1] Arizona State Univ, Sch Math & Stat Sci, Tempe, AZ 85287 USA

[2] Air Force Res Lab, Wright Patterson AFB, OH USA

[3] Dartmouth Coll, Dept Math, Hanover, NH 03755 USA

关键词: Synthetic aperture radar;    Autofocus;    Phase error correction;    High order sparsity regularization;    Phase synchronization;   

DOI  :  10.1016/j.jcp.2018.07.059

来源: Elsevier

【 摘 要 】

Imaging via synthetic aperture radar (SAR) is a well-established technique for effective scene reconstruction, with resolution up to a few centimeters. The measurement process requires the round trip time for the electromagnetic waves to travel to the scene and return back to the sensing mechanism. While hypothetically the round trip time can be exactly determined, in practice this distance can only be approximated, leading to errors in the round trip time estimates. These errors manifest as phase errors on the data and produce defocused imagery, making information extraction difficult. This investigation develops an autofocusing technique that exploits the correlation of the phase error on both the azimuth angle and spatial (cycles/meter) frequencies while also enforcing the piecewise smooth nature of the image. Our method estimates the phase error correction and the image through a joint optimization procedure. Specifically, our method incorporates a phase synchronization technique to estimate the unknown two-dimensional phase error. High order regularization is used in the optimization procedure, which helps to reduce speckle in the SAR image. (C) 2018 Elsevier Inc. All rights reserved.

【 授权许可】

Free