Advanced high-order nonlinear chirp scaling algorithm for high-resolution wide-swath spaceborne SAR

Men, Zhirong; Wang, Pengbo; Chen, Jie; Li, Chunsheng; Liu, Wei; Yang, Wei

doi:10.1016/j.cja.2020.08.035

Cited by 7 publications

(8 citation statements)

References 17 publications

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“…10 and Fig. 11, whereas the results of the NCS algorithm proposed in [25]- [28] for comparison are shown in Fig. 12 and Fig.…”

Section: A Simulation Resultsmentioning

confidence: 99%

“…Suppose the final image with full resolution has Nr range samples and Na azimuth samples. The computational complexity of the proposed algorithm and the reference algorithm in [28] is compared in Table III. The length of the HC sliding window is K1 and the Doppler parameters are updated every K2 range cells in this paper.…”

Section: B Computational Burdenmentioning

confidence: 99%

“…However, the premise of azimuth invariance is untenable for the HRWS space-borne SAR system working in sliding spotlight mode, which means the Doppler phase errors for the marginal targets will become non-negligible. The Nonlinear Chirp Scaling (NCS) algorithm is a most widely adopted method in handling the azimuth variance problem [25]- [28]. The main idea is utilizing a cubic phase perturbation to equalize the azimuth-varying Doppler parameters.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An Improved Imaging Algorithm for HRWS Space-Borne SAR Data Processing Based on CVPRI

Guo

Wang

Zhou

et al. 2023

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

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In space-borne synthetic aperture radar (SAR), the sliding spotlight mode can acquire images with both highresolution and wide-swath in azimuth direction. Due to the significant two-dimensional (2-D) spatial variance of Doppler parameters, the traditional imaging algorithms based on the conventional range models is not available. In this paper, the strategy of continuously varying pulse repetition interval (CVPRI) is likely to lead to a novel approach to dealing with the azimuth variance problem to realize high-resolution wide-swath (HRWS) imaging in azimuth direction for sliding spotlight SAR. First, the eighth-order Taylor expansion of the modified equivalent squint range model (MESRM-TE8) is adopted, and the accuracy of MESRM-TE8 is accordingly explained. Then, the properties of the spatial variance for the MESRM-TE8 are analyzed in detail, based on which the strategy of CVPRI is given theoretically to eliminate the azimuth variance. An improved imaging algorithm based on CVPRI is subsequently proposed to address the azimuthal-variant Doppler parameters and realize a batch data processing of a large scene in azimuth frequency domain. The extended scaling method is integrated in this algorithm to uniformly compensate cubic phase modulation introduced by CVPRI and circumvent azimuth time folding caused by sub-aperture processing in the focused image. Finally, the effectiveness of the CVPRI strategy and the proposed algorithm is demonstrated by the simulation results.

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“…10 and Fig. 11, whereas the results of the NCS algorithm proposed in [25]- [28] for comparison are shown in Fig. 12 and Fig.…”

Section: A Simulation Resultsmentioning

confidence: 99%

Section: B Computational Burdenmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An Improved Imaging Algorithm for HRWS Space-Borne SAR Data Processing Based on CVPRI

Guo

Wang

Zhou

et al. 2023

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

Self Cite

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“…, , Δ The chirp scaling (CS) algorithm [26] was used for the main satellite monostatic SAR imaging, which initially corrects the linear range migration along the range dimension, followed by range cell migration correction (RCMC) and range-matched filtering to achieve range compression [27]. Subsequently, matched filtering is performed to accomplish azimuth compression, resulting in the acquisition of 2D-focused strip SAR images.…”

Section: Bistatic Sar Time Synchronizationmentioning

confidence: 99%

Imaging and Interferometric Mapping Exploration for PIESAT-01: The World’s First Four-Satellite “Cartwheel” Formation Constellation

Zhang,

Qian,

et al. 2024

Atmosphere

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The PIESAT-01 constellation is the world’s first multi-baseline distributed synthetic aperture radar (SAR) constellation with a “Cartwheel” formation. The “Cartwheel” formation is a unique formation in which four satellites fly in companion orbits, ensuring that at any given moment, the main satellite remains at the center, with three auxiliary satellites orbiting around it. Due to this unique configuration of the PIESAT-01 constellation, four images of the same region and six pairs of baselines can be obtained with each shot. So far, there has been no imaging and interference research based on four-satellite constellation measured data, and there is an urgent need to explore algorithms for the “Cartwheel” configuration imaging and digital surface model (DSM) production. This paper introduces an improved bistatic SAR imaging algorithm under the four-satellites interferometric mode, which solves the problem of multi-orbit nonparallelism in imaging while ensuring imaging coherence and focusing ability. Subsequently, it presents an interferometric processing method for the six pairs of baselines, weighted fusion based on elevation ambiguity from different baselines, to obtain a high-precision DSM. Finally, this paper selects the Dingxi region of China and other regions with diverse terrains for imaging and DSM production and compares the DSM results with ICESat-2 global geolocated photon data and TanDEM DSM data. The results indicate that the accuracy of PIESAT-01 DSM meets the standards of China’s 1:50,000 scale and HRTI-3, demonstrating a high level of precision. Moreover, PIESAT-01 data alleviate the reliance on simulated data for research on multi-baseline imaging and multi-baseline phase unwrapping algorithms and can provide more effective and realistic measured data.

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“…SAR-imaging algorithms are divided into two main categories: time-domain and frequency-domain imaging algorithms. The most widely used frequency-domain imaging algorithms are distance Doppler (RD) [3], beam domain (omega-K, ωk) [4], and Chisp scaling (CS) algorithms [5]. All frequency-domain algorithms require a fast Fourier transform for fast imaging purposes, but to take advantage of the FFT, a polynomial approximation to the echo model has to be made.…”

Section: Introductionmentioning

confidence: 99%

A Backprojection-Based Autofocus Imaging Method for Circular Synthetic Aperture Radar

Li,

Ma,

Chu

et al. 2023

Electronics

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Circular synthetic aperture radar (CSAR) can obtain higher image resolution and more target information through 360° observation of the target. However, CSAR is often subject to motion errors due to the sensor’s accuracy limitations and the unique trajectory of the system. The autofocusing back projection algorithm based on the optimization of image sharpness compensates for motion errors through phase-error estimation. This method can attain relatively good performance while assuming the same error for all pixels; it ignores the spatial variance of motion errors. In order to solve this problem, this paper proposes an autofocusing method based on the Prewitt operator and particle swarm optimization (PSO), which first extracts the subaperture image feature points as a new dataset using the Prewitt operator, estimates the radar slope error on the new dataset using PSO, and subsequently compensates the subaperture image. Finally, the subaperture images are synthesized using an image-alignment method. The results of both the simulated experiments and the measured data validate the effectiveness of this method.

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Advanced high-order nonlinear chirp scaling algorithm for high-resolution wide-swath spaceborne SAR

Cited by 7 publications

References 17 publications

An Improved Imaging Algorithm for HRWS Space-Borne SAR Data Processing Based on CVPRI

An Improved Imaging Algorithm for HRWS Space-Borne SAR Data Processing Based on CVPRI

Imaging and Interferometric Mapping Exploration for PIESAT-01: The World’s First Four-Satellite “Cartwheel” Formation Constellation

A Backprojection-Based Autofocus Imaging Method for Circular Synthetic Aperture Radar

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