Polar format algorithm based on fast Gaussian grid non‐uniform fast Fourier transform for spotlight synthetic aperture radar imaging

Fan, Bo; Wang, Jiantao; Qin, Yuliang; Wang, Hongqiang; Xiao, Hanguang

doi:10.1049/iet-rsn.2013.0199

Cited by 11 publications

(12 citation statements)

References 36 publications

(42 reference statements)

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“…R HOT (x 0 , y 0 , θ) is the higher order term which is neglected in planar wave approximation [10,13,14]. φ 0 and θ are depression and corresponding azimuth angles in coordinate system and the expression is…”

Section: Theory Of Visar Imaging Algorithmmentioning

confidence: 99%

“…Spotlight mode is the main mode for ViSAR [9]. The Back-Projection (BP) [10][11][12] and the polar format algorithm (PFA) [4,13,14] are two useful methods for spotlight SAR imaging. Compared with the BP algorithm, PFA is more efficient and easier to integrate with autofocus algorithms like Map-Drift (MD) [15] and phase gradient autofocus (PGA) [16].…”

Section: Introductionmentioning

confidence: 99%

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A Novel Generation Method of High Quality Video Image for High Resolution Airborne ViSAR

Chen

et al. 2021

Remote Sensing

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Video synthetic aperture radar (ViSAR) can provide long-time surveillance of a region of interest (ROI), which is one of the hotspot directions in the SAR field. In order to better display ViSAR, a high resolution and high frame rate are needed. Azimuth integration angle and sub-aperture overlapping ratio, which determine the image resolution and frame rate, respectively, are analyzed in depth in this paper. For SAR imaging algorithm, polar format algorithm (PFA) is applied, which not only has high efficiency but is also easier to integrate with autofocus algorithms. Due to sensitivity to motion error, it is very difficult to obtain satisfactory focus quality, especially for SAR systems with a high carrier frequency. The three-step motion compensation (MOCO) proposed in this paper, which combines GPS-based MOCO, map-drift (MD) and phase gradient autofocus (PGA), can effectively compensate for motion error, especially for short wavelengths. In ViSAR, problems such as jitter, non-uniform grey scale and low image signal noise ratio (SNR) between different aspects images also need to be considered, so a ViSAR generation method is proposed to solve the above problems. Finally, the results of ViSAR in THz and Ku band demonstrate the effectiveness and practicability of the proposed method.

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Section: Theory Of Visar Imaging Algorithmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Novel Generation Method of High Quality Video Image for High Resolution Airborne ViSAR

Chen

et al. 2021

Remote Sensing

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“…Therefore some mature and efficient imaging algorithms may not available. At present, Back-Projection (BP) [3]- [5] and PFA [8]- [10] are able to handle curvilinear trajectory. Time-domain BP algorithm is suitable for any trajectory imaging whether it's a straight trajectory or curvilinear trajectory.…”

Section: Introductionmentioning

confidence: 99%

“…What's more, compared with BP algorithm, PFA is more efficient for high resolution imaging and easier to integrate with autofocus algorithms like Map-Drift (MD) [6] and Phase gradient autofocus (PGA) [7]. Therefore PFA is widely used in WAS-SAR imaging [8]- [11]. Most of the mature and efficient frequency-domain imaging algorithms such as Range Doppler (RD) [12] and Chirp Scaling (CS) [13] are relying on the model of straight path and constant velocity.…”

Section: Introductionmentioning

confidence: 99%

Extended Polar Format Algorithm for Large-Scene High-Resolution WAS-SAR imaging

Chen

Wang

et al. 2021

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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The polar format algorithm (PFA) is a frequencydomain algorithm with high computational efficiency especially for the high resolution imaging applications in wide angle staring synthetic aperture radar (WAS-SAR). Because of the image distortion and defocus caused by plane wave assumption, the effective imaging scene is limited to a small region which is defined as defocus-negligible region. In this paper, a novel sub-block imaging algorithm which firstly applied to WAS-SAR is proposed. This method combines sub-block imaging and spatially variant post filtering (SVPF) which can not only effectively extend depth of focus (DOF) of PFA but also greatly reduces computational burden. What's more, the method of mosaic image is proposed in this paper which can eliminate discontinuity between adjacent sub-blocks. Firstly, the large scene is segmented into multiple regions along range direction and the size of each region is still larger than that of defocus-negligible region. Secondly, refocusing is implemented by a phase compensation of the already de-chirped signal with the center of sub-blocks respectively and each sub-block image is formed by PFA. Thirdly, the region in each sub-block that exceeds the defocus-negligible region is corrected by SVPF and the image distortion can be corrected by 2-D interpolation. Finally, mosaic image method is applied to get the large-scene image with high quality. The algorithm proposed in this paper is efficient and solve the problems in the process of SAR image mosaic such as dislocation and grey scale differences. The simulated and experimental data results demonstrate the effectiveness and practicability of the proposed algorithm.Index Terms-wide angle staring synthetic aperture radar (WAS-SAR), polar format algorithm (PFA), large scene, high resolution, sub-block imaging, SVPF

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“…Non-uniform fast Fourier transforms (NUFFTs) are efficient, accurate alternatives to standard FDMs, particularly for range-migration algorithms [4], [5], [6]. NUFFTs do not suffer from beam-width limitations as do chirp-z transforms [7] and its computational complexity is O(N 2 log N ) for N data points.…”

Section: Introductionmentioning

confidence: 99%

Thresholded Non-Uniform Fourier Frame-Based Reconstruction for Stripmap SAR

McKay¹,

Gelb²,

Jayasuriya³

et al. 2019

Preprint

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Fourier domain methods are fast algorithms for SAR imaging. They typically involve an interpolation in the frequency domain to re-grid non-uniform data so inverse fast Fourier transforms can be performed. In this paper, we apply a frame reconstruction algorithm, extending the non-uniform fast Fourier transform, to stripmap SAR data. Further, we present an improved thresholded frame reconstruction algorithm for robust performance and improved computational efficiency. We demonstrate compelling results on real stripmap SAR data.

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Polar format algorithm based on fast Gaussian grid non‐uniform fast Fourier transform for spotlight synthetic aperture radar imaging

Cited by 11 publications

References 36 publications

A Novel Generation Method of High Quality Video Image for High Resolution Airborne ViSAR

A Novel Generation Method of High Quality Video Image for High Resolution Airborne ViSAR

Extended Polar Format Algorithm for Large-Scene High-Resolution WAS-SAR imaging

Thresholded Non-Uniform Fourier Frame-Based Reconstruction for Stripmap SAR

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