Focusing Hypersonic Vehicle-Borne SAR Data Using Radius/Angle Algorithm

Tang, Shiyang; Guo, Ping; Zhang, Linrang; So, Hing Cheung

doi:10.1109/tgrs.2019.2936246

Cited by 24 publications

(8 citation statements)

References 35 publications

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“…In order to avoid the separate processing of the 2D spatial variation of the traditional algorithm and improve the imaging efficiency, the spatially variant properties in different imaging coordinate systems have been investigated, and an optimal orthogonal imaging coordinate system was established in [33]. Moreover, considering that the biggest difference between CF-SAR and Conv-SAR is the motion trajectory, modeling in the curvilinear coordinate system is bound to further reduce the impact of the radar flight trajectory; this inference was also verified in the frequency and time domains by Tang et al [34] and the research in [35], respectively. Overall, the ICST approaches provide a novel data processing idea.…”

Section: Imaging Coordinate System Transformationmentioning

confidence: 91%

Curvilinear Flight Synthetic Aperture Radar (CF-SAR): Principles, Methods, Applications, Challenges and Trends

et al. 2022

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The research into curvilinear flight synthetic aperture radar (CF-SAR) is the inevitable result of the comprehensive practicality of SAR. The flight path of the SAR platform in real applications, which is highly nonlinear or curvy due to three-dimensional velocity and acceleration, cannot be described by the traditional uniform linear motion model. New mathematical models, signal characteristics, imaging algorithms, and system design criteria must be proposed and investigated for CF-SAR. This paper provides a comprehensive overview of CF-SAR. Firstly, the basic concept, unified model, and general signal characteristics of CF-SAR are defined, derived, and analyzed, respectively. Additionally, the advantages and drawbacks of current methodologies are reviewed. Discussions on the CF-SAR’s applications are presented from the perspective of typical platforms, new configurations, and advanced technologies, which are suitable means to fulfill the increasing user requirements. Finally, the challenges faced by CF-SAR are summarized, and some future trends for the study of CF-SAR are explored. Hopefully, this paper will serve as a reference for SAR researchers/engineers and stimulate the future development and actual application of CF-SAR.

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Section: Imaging Coordinate System Transformationmentioning

confidence: 91%

Curvilinear Flight Synthetic Aperture Radar (CF-SAR): Principles, Methods, Applications, Challenges and Trends

et al. 2022

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“…Synthetic aperture radar (SAR) is a technique that is receiving more and more attention worldwide nowadays, given that it is capable of imaging the observed scenes of interest, regardless of weather conditions, both day and night [1][2][3][4][5][6]. SAR has been widely employed in different applications, such as environmental observation, traffic monitoring, sea-surface surveillance, and antiterrorism.…”

Section: Introductionmentioning

confidence: 99%

Fast Approach for SAR Imaging of Ground-Based Moving Targets Based on Range Azimuth Joint Processing

et al. 2022

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The synthetic aperture radar (SAR) images of a moving target may be out of focus, given the motions of a non-cooperative target. Doppler ambiguities, including the Doppler center blur and spectrum ambiguity, will easily appear due to the limitations of pulse repetition frequency, which causes difficulty in moving-target imaging. Therefore, a robust fast Doppler ambiguity approach for SAR imaging of a ground-based moving target using range azimuth joint processing (RAJP) is presented. Firstly, the use of RAJP, based on a two-dimensional cross-correlation function and linear range cell migration (LRCM) compensation function, is proposed to simultaneously obtain the first- and second-order phase parameters in the fast-time and azimuth-frequency domains. Then, a corresponding azimuth reference function is constructed to image the moving target. Additionally, a principal component analysis-based operation is introduced to solve the mismatch with the LRCM compensation function. The couplings between the range and azimuth and between the first- and second-order parameters can be simultaneously decoupled by the proposed RAJP operation, which simplifies the processing steps. The developed approach can simultaneously obtain the first- and second-order parameters in the fast-time and azimuth-frequency domains, which avoids the propagation error of parameter estimation caused by the stepwise processing operation. The proposed method is relatively fast, given the need for fewer processing steps. The presented approach is robust in terms of Doppler ambiguity and handles the blind speed sidelobe well. In this study, simulated and real data are processed to verify the proposed approach.

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“…Hypersonic platform-borne synthetic aperture radar (SAR) imaging has a promising application prospect [1][2][3][4][5]. The hypersonic platform-borne SAR works at a typical altitude between 20 and 100 km with a speed over Mach 5 [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…As hypersonic platform-borne SAR imaging plays an important role in civilian and military fields, many researchers studied it from different aspects [1][2][3][4][5]14,15]. For range migration and pulse broadening phenomenon caused by the "scale effect" which will lead to the decrease of SAR imaging resolution, Xu [3] proposed the corresponding compensating factors in matched filleter to solve this problem.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Hypersonic Platform-Borne SAR Imaging: A Physical Perspective

Song

Bai

et al. 2021

Remote Sensing

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The usage of a hypersonic platform for remote sensing application has promising prospects, especially for hypersonic platform-borne synthetic aperture radar (SAR) imaging. However, the high-speed of hypersonic platform will lead to extreme friction between the platform and air, which will cause the ionization of air. The ionized gas forms the plasma sheath wrapped around the hypersonic platform. The plasma sheath will severely affect the propagation of SAR signal and further affect the SAR imaging. Therefore, hypersonic platform-borne SAR imaging should be studied from a physical perspective. In this paper, hypersonic platform-borne SAR imaging under plasma sheath is analyzed. The SAR signal propagation in plasma sheath is computed using scatter matrix method. The proposed SAR signal model is verified by using a ground experiment system. Moreover, the effect of attenuation caused by plasma sheath on SAR imaging is studied under different SAR parameters and plasma sheath. The result shows that attenuation caused by plasma sheath will degrade the SAR imaging quality and even cause the point and area targets to be submerged into the noise. The real SAR images under plasma sheath also illustrate this phenomenon. Furthermore, by studying imaging results under different SAR and plasma parameters, it can be concluded that the severe degradation of SAR imaging quality appears at condition of high plasma sheath electron density and low SAR carrier frequency. The work in this paper will be beneficial for the study of hypersonic platform-borne SAR imaging and design of hypersonic SAR imaging systems in the future.

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Focusing Hypersonic Vehicle-Borne SAR Data Using Radius/Angle Algorithm

Cited by 24 publications

References 35 publications

Curvilinear Flight Synthetic Aperture Radar (CF-SAR): Principles, Methods, Applications, Challenges and Trends

Curvilinear Flight Synthetic Aperture Radar (CF-SAR): Principles, Methods, Applications, Challenges and Trends

Fast Approach for SAR Imaging of Ground-Based Moving Targets Based on Range Azimuth Joint Processing

Analysis of Hypersonic Platform-Borne SAR Imaging: A Physical Perspective

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