Focusing highly squinted missile-borne SAR data using azimuth frequency nonlinear chirp scaling algorithm

Zhang, Yan; Qu, Tan

doi:10.1007/s11554-021-01135-6

Cited by 4 publications

(3 citation statements)

References 14 publications

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“…In the case with highly squinted angle, the azimuth space variance and the coupling between range and azimuth dimension will become seriously in imaging, thus an azimuth frequency nonlinear chirp scaling (AFNCS) algorithm is proposed to solve this problem. Based on linear range walk correction, in the contribution by Zhang and Qu "Focusing highly squinted missile-borne SAR data using azimuth frequency nonlinear chirp scaling algorithm," a novel chirp scaling algorithm is adopted to correct the range migration, and then a high-order phase filtering factor is introduced into the azimuth dimension frequency domain to decrease the azimuth space variance [11]. In addition, combined with the SPECtral Analysis method, the image is focused in the Doppler domain.…”

Section: Applicationsmentioning

confidence: 99%

Special issue on deep learning for emerging embedded real-time image and video processing systems

Jeon

Chehri

2021

J Real-Time Image Proc

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Section: Applicationsmentioning

confidence: 99%

Special issue on deep learning for emerging embedded real-time image and video processing systems

Jeon

Chehri

2021

J Real-Time Image Proc

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“…Then, they can hardly be applied to the case of high-squint angle due to extremely severe RAC [36,37]. Therefore, multiple nonlinear CS (NCS) algorithms [38][39][40][41][42][43][44][45][46] are presented to decoupled the RAC. To remove more severe RAC of the signal, the third-order CS function was used at first [38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

“…To further increase the image precision, the CS function was then upgraded to the fourth order [42]. Afterwards, NCS processing has been used for numerous processing methods or working modes, such as fractional chirp scaling algorithm (FrCSA) [43], 2D NCS [44], Blind NCS [45], and Mosaic SAR [46]. Specifically, An et al [47] proposed a modified azimuth NCS algorithm by using a fourth-order CS function to realize highly squint airborne SAR imaging.…”

Section: Introductionmentioning

confidence: 99%

A Modified Frequency Nonlinear Chirp Scaling Algorithm for High-Speed High-Squint Synthetic Aperture Radar with Curved Trajectory

Deng,

Huang,

Chen

et al. 2024

Remote Sensing

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The imaging of high-speed high-squint synthetic aperture radar (HSHS-SAR), which is mounted on maneuvering platforms with curved trajectory, is a challenging task due to the existence of 3-D acceleration and the azimuth spatial variability of range migration and Doppler parameters. Although existing imaging algorithms based on linear range walk correction (LRWC) and nonlinear chirp scaling (NCS) can reduce the range–azimuth coupling of the frequency spectrum (FS) and the spatial variability of the Doppler parameter to some extent, they become invalid as the squint angle, speed, and resolution increase. Additionally, most of them ignore the effect of acceleration phase calibration (APC) on NCS, which should not be neglected as resolution increases. For these issues, a modified frequency nonlinear chirp scaling (MFNCS) algorithm is proposed in this paper. The proposed MFNCS algorithm mainly includes the following aspects. First, a more accurate approximation of range model (MAARM) is established to improve the accuracy of the instantaneous slant range history. Second, a preprocessing of the proposed algorithm based on the first range compression, LRWC, and a spatial-invariant APC (SIVAPC) is implemented to eliminate most of the effects of high-squint angle and 3-D acceleration on the FS. Third, a spatial-variant APC (SVAPC) is performed to remove azimuth spatial variability introduced by 3-D acceleration, and the range focusing is accomplished by the bulk range cell migration correction (BRCMC) and extended secondary range compression (ESRC). Fourth, the azimuth-dependent characteristics evaluation based on LRWC, SIVAPC, and SVAPC is completed to derive the MFNCS algorithm with fifth-order chirp scaling function for azimuth compression. Consequently, the final image is focused on the range time and azimuth frequency domain. The experimental simulation results verify the effectiveness of the proposed algorithm. With a curved trajectory, HSHS-SAR imaging is carried out at a 50° geometric squint angle and 500 m × 500 m imaging width. The integrated sidelobe ratio and peak sidelobe ratio of the point targets at the scenario edges approach the theoretical values, and the range-azimuth resolution is 1.5 m × 3.0 m.

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A Monostatic Forward-Looking Staring Spotlight SAR Raw Data Generation and Hybrid-Domain Image Formation Modifications Based on Extended Azimuth Nonlinear Chirp Scaling Autofocusing

Shahrezaei

Kim

2023

IEEE Trans. Aerosp. Electron. Syst.

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Focusing highly squinted missile-borne SAR data using azimuth frequency nonlinear chirp scaling algorithm

Cited by 4 publications

References 14 publications

Special issue on deep learning for emerging embedded real-time image and video processing systems

Special issue on deep learning for emerging embedded real-time image and video processing systems

A Modified Frequency Nonlinear Chirp Scaling Algorithm for High-Speed High-Squint Synthetic Aperture Radar with Curved Trajectory

A Monostatic Forward-Looking Staring Spotlight SAR Raw Data Generation and Hybrid-Domain Image Formation Modifications Based on Extended Azimuth Nonlinear Chirp Scaling Autofocusing

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