A Novel High-Squint Spotlight SAR Raw Data Simulation Scheme in 2-D Frequency Domain

Guo, Zhengwei; Fu, Zewen; Chang, Jike; Wu, Lin; Li, Ning

doi:10.3390/rs14030651

Cited by 7 publications

(5 citation statements)

References 37 publications

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“…The Kth sub-aperture is processed. The phase compensation of the range-compressed echo is based on the slant distance from the radar to the polar coordinate pixel, and the impulse response function (IRF) in the azimuth direction (i.e., the polar angle direction) can be obtained after the integration, as shown in Formula (11).…”

Section: Principle Of Wfbpmentioning

confidence: 99%

“…Typical frequency domain algorithms include range-Doppler (RD) algorithm [9], chirp scaling (CS) [10], and ω−k algorithm. However, each algorithm has its own scope of application [11], and various approximations are introduced in the calculation process, which reduces the imaging accuracy [12,13]. The representative timedomain imaging algorithm is the backprojection (BP) algorithm.…”

Section: Introductionmentioning

confidence: 99%

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An Efficient Backprojection Algorithm Based on Wavenumber-Domain Spectral Splicing for Monostatic and Bistatic SAR Configurations

Sun

Chen

et al. 2022

Remote Sensing

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This paper introduces a fast backprojection synthetic aperture radar (SAR) imaging algorithm based on wavenumber-domain spectral splicing. The traditional fast backprojection (FBP) algorithm establishes the polar coordinate system with the center of the sub-aperture as the origin. Therefore, the coordinates of the image obtained from each sub-aperture are different. Sub-aperture images must be projected to a uniform coordinate system before they can be coherently superimposed to form the final image, which requires a large amount of calculation. In order to deal with this problem, this paper proposes a novel imaging method, which uses the same polar coordinate system for each sub-aperture. The sub-aperture images are then spliced in the wavenumber-domain, and directly added after upsampling. This method avoids the projection from each sub-aperture to the uniform coordinate system, thus improving the imaging accuracy and efficiency. At the same time, the algorithm is suitable for various configurations, and can achieve good imaging results for bistatic forward-looking SAR and high-speed mobile platform. Finally, simulations are presented to demonstrate the effectiveness of the algorithm.

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Section: Principle Of Wfbpmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Efficient Backprojection Algorithm Based on Wavenumber-Domain Spectral Splicing for Monostatic and Bistatic SAR Configurations

Sun

Chen

et al. 2022

Remote Sensing

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“…Earlier studies [18,19] did not consider the actual mission environment and instead used the slant range between the center of the SAL and the target as an arbitrary constant value to solve the unknown parameters in the SAR geometry. In other studies [11,20,21], when performing an SAR simulation, the slant range from the center of the SAL was assumed to be a constant value and that from the SAL's starting point, which is known in the current mission environment, was not considered.…”

Section: Introductionmentioning

confidence: 99%

Analysis Method for Determining Optimal Synthetic Aperture Time Using Estimated Range and Doppler Cone Angle at the Center of Synthetic Aperture Length

Kim

Lim

Shin

2023

J. Electromagn. Eng. Sci

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Synthetic aperture time (SAT) is a crucial component for acquiring high-quality synthetic aperture radar images with an excellent target cross-range resolution. SAT is analyzed using the range and Doppler cone angle at the center of the synthetic aperture length (SAL). However, in a real flight mission setting, only the range and Doppler cone angle at the SAL’s starting point are determined. Therefore, we present a method for estimating the range and Doppler cone angle at the center of the SAL to calculate an accurate SAT that is suitable for the spatial resolution of the assigned mission. We performed an iterative analysis of SAT at the range and Doppler cone angle at the starting point of the SAL (original SAT) and at the center of the SAL (proposed SAT). Consequently, the proposed SAT decreased by 0.69%–16.14% compared to the original SAT at a resolution of 0.1–3.0 m.

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“…It improves the simulation efficiency compared to time-domain methods and generates raw data by coherently stacking the echoes of each pulse from the radar. The two-dimensional frequency-domain method [16,17] uses the principle that the echo signal is the two-dimensional convolution of the target scattering coefficient and SAR system impulse function to accelerate the implementation of the signal convolution in the two-dimensional frequency domain, greatly improving the efficiency. The inverse imaging processing method [10,18] uses any SAR image as a reflectivity map and uses the inverse processing of the imaging algorithm to obtain SAR raw data.…”

Section: Introductionmentioning

confidence: 99%

Raw Data Simulation of Spaceborne Synthetic Aperture Radar with Accurate Range Model

Jiang

et al. 2023

Remote Sensing

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Simulated raw data have become an essential tool for testing and assessing system parameters and imaging performance due to the high cost and limited availability of real raw data from spaceborne synthetic aperture radar (SAR). However, with increasing resolution and higher orbit altitudes, existing simulation methods fail to generate SAR simulated raw data that closely resemble real raw data. This is due to approximations such as curved orbits, “stop-and-go” assumption, and Earth’s rotation, among other factors. To overcome these challenges, this paper presents an accurate range model with a “nonstop-and-go” configuration for raw data simulation based on existing time-domain simulation methods. We model the SAR echo signal and establish a precise space geometry for spaceborne SAR. Additionally, we precisely identify the target illumination area based on elliptical beams through space coordinate transformation. Finally, the SAR raw data were accurately simulated using high-precision time-domain simulation methods. The accuracy of the proposed model was validated by comparing it with the traditional hyperbolic model and the curved orbit model with “stop-and-go” assumption through image processing of the generated raw data. Through the analysis of point target quality parameters, the errors of various parameters in our distance model compared with the other two models are within 1%. Furthermore, this simulation method can be adapted to simulate raw data of other modes and satellite orbits by adjusting beam control and satellite orbit parameters, respectively. The proposed simulation method demonstrated high accuracy and versatility, thereby providing a valuable contribution to the development of remote sensing technology.

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A Novel High-Squint Spotlight SAR Raw Data Simulation Scheme in 2-D Frequency Domain

Cited by 7 publications

References 37 publications

An Efficient Backprojection Algorithm Based on Wavenumber-Domain Spectral Splicing for Monostatic and Bistatic SAR Configurations

An Efficient Backprojection Algorithm Based on Wavenumber-Domain Spectral Splicing for Monostatic and Bistatic SAR Configurations

Analysis Method for Determining Optimal Synthetic Aperture Time Using Estimated Range and Doppler Cone Angle at the Center of Synthetic Aperture Length

Raw Data Simulation of Spaceborne Synthetic Aperture Radar with Accurate Range Model

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