scholarly journals High-Squint FMCW SAR Imaging via Wavenumber Domain Algorithm

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Hui Bi ◽  
Hao Li ◽  
Wei Liang
Keyword(s):  
High Resolution ◽  
Continuous Wave ◽  
Synthetic Aperture ◽  
Transmission Power ◽  
Wavenumber Domain ◽  
Radar Systems ◽  
Pulsed Mode ◽  
Sar Imaging ◽  
Good Potential ◽  
Common Technique

Nowadays, because the frequency modulation continuous-wave (FMCW) synthetic aperture radar (SAR) shows good potential in minimal transmission power and weight reduction of radar systems, it has been widely used and has become a common technique in modern short-range high-resolution earth observation. Different from the conventional pulsed mode, the stop-to-go approximation is not valid in FMCW SAR. Thus, the typical SAR imaging methods need to be modified to adapt the continuous-wave scheme in practical data processing. In this letter, a wavenumber domain algorithm (WDA) is derived and used for the FMCW SAR imaging under squint and high-squint cases. With the help of the exact scene recovery ability of the proposed WDA, we can achieve the accurate recovery of the considered scene even when using the collected high-squint data and hence obtain the well-focused high-resolution image of the considered scene. Experimental results with simulated and airborne data verify the effectiveness of the proposed method.

scholarly journals Results of inverse synthesis of two-dimensional radar images of objects with autofocusing in wide sectors of angles.

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
S.I. Moryakov ◽  
◽  
S.M. Nesterov ◽  
I.A. Skorodumov ◽  
◽  
...  
Keyword(s):  
High Resolution ◽  
Synthetic Aperture Radar ◽  
Large Angle ◽  
Synthetic Aperture ◽  
Synthetic Image ◽  
Wide Angle ◽  
Two Dimensional ◽  
Radar Images ◽  
Radar Systems ◽  
Wideband Radar

Modern wideband radar systems makes possible to obtain high resolution inverse synthetic aperture radar images of objects. One of the difficult actual approaches in radar test facilities is wide angle autofocusing processing. This paper proposed a recommendations to wide angle (above 10 degrees) inverse synthetic image autofocusing processing based on dividing a large angle sector into several small sections. Also proposed an experimental results of autofocusing processing in 30° and 60° angle sector.

scholarly journals A Modified Cartesian Factorized Backprojection Algorithm Integrating with Non-Start-Stop Model for High Resolution SAR Imaging

2020 ◽  
Vol 12 (22) ◽  
pp. 3807
Author(s):  
Da Liang ◽  
Heng Zhang ◽  
Tingzhu Fang ◽  
Haoyu Lin ◽  
Dacheng Liu ◽  
...  
Keyword(s):  
High Resolution ◽  
Frequency Modulation ◽  
Simulation Experiment ◽  
Synthetic Aperture ◽  
Time Varying ◽  
Sar Image ◽  
Imaging Processing ◽  
Sar Imaging ◽  
Disaster Monitoring ◽  
Modulation Rate

High resolution synthetic aperture radar (SAR) imaging has extensive application value especially in military reconnaissance and disaster monitoring. The motion of the satellite during the transmission and reception of the signal introduces notable errors in the high resolution SAR spotlight mode, which will lead to a defocused SAR image if not handled. To address this problem, an accurate correct echo model based on non-start-stop model is derived to describe the property of the SAR signal in the paper. Then, in the imaging processing, an azimuth-time-varying range frequency modulation rate is used for range compression. The range history and compensation phase are also derived based on the correct echo model. Then, combining the correct echo model and Cartesian factorized backprojection (CFBP) algorithm, a modified CFBP algorithm is proposed for SAR imaging to improve the accuracy and efficiency of processing. Besides, the influence of residual error due to mismatch is analyzed in detail. In the end, the simulation experiment and Gaofen-3 (GF-3) data experiment are carried out to demonstrate the feasibility of the proposed algorithm.

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