A Hybrid SAR/ISAR Approach for Refocusing Maritime Moving Targets with the GF-3 SAR Satellite

Yan, Zhishuo; Zhang, Yi; Zhang, Heng

doi:10.3390/s20072037

Cited by 4 publications

(3 citation statements)

References 38 publications

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“…The typical SAR satellite mainly include India's Sky Eye 1 (RISAT-1), which adopts an unregulated single-bus power supply system based on MPPT, has a small number of system equipment, relatively low cost, and good dynamic characteristics [5]; limited to the platform load and the SAR pulse load sharing a bus, the serious bus pulse noise interference makes the platform load power scalability poor. The German Terrestrial Radar-X-band satellite (Terra SAR-X) provides stable power demand for the platform load through the DC/DC converter on the unregulated bus, the SAR load bus fluctuation caused by pulsed power supply also increases the DC/DC converter design difficulty [6]- [7]. China's Gaofen No.3 adopts a dual independent bus design, that is, the platform load uses a fully regulated bus, and the SAR load uses an unregulated bus; they are independently equipped with solar arrays and battery packs; although the two buses do not interfere with each other, this scheme requires a large number of equipment, relatively large volume and quality, and the technical scheme is not optimized enough.…”

Section: Features Of the Sar Satellite Power Systemmentioning

confidence: 99%

Design of Power Supply System for High Power SAR Satellite

Liu

Bao

et al. 2022

J. Phys.: Conf. Ser.

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Synthetic Aperture Radar (SAR) satellite power system has the characteristics of high power, pulse power supply and fast response speed. Based on the combination of domestic and foreign SAR satellite power supply structures, a SAR satellite power supply system scheme with a composite bus architecture is proposed in this paper. By adding battery discharge regulators (BDR) between the platform bus and the SAR load bus as a grid-connected controller, the SAR load bus can supply power to the platform load, and the solar array and battery pack can be used efficiently while achieving dual bus output. Aiming at the composite bus, this paper also proposes an efficient high-power filter technology. Finally, the ground test results verify the correctness of the scheme, which can meet the different power supply requirements of the SAR satellite stable and pulse load equipment.

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Section: Features Of the Sar Satellite Power Systemmentioning

confidence: 99%

Design of Power Supply System for High Power SAR Satellite

Liu

Bao

et al. 2022

J. Phys.: Conf. Ser.

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show abstract

“…In Ref. 6, based on hybrid SAR/ISAR processing, an improved rank-one phase estimation method is proposed to achieve accurate phase error, to maintain robustness to noise and to perform well in estimating various phase errors, through using an iterative two-step convergence process. A hybrid SAR-ISAR imaging method is proposed in Ref.…”

Section: Introductionmentioning

confidence: 99%

Improved ship imaging algorithm for geosynchronous synthetic aperture radar (SAR) featured by subaperture time window selection optimization and inverse SAR translational compensation

Zhou

Zhang

et al. 2023

J. Appl. Rem. Sens.

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.An inverse synthetic aperture radar processing-based algorithm is improved for ship imaging in geosynchronous synthetic aperture radars (GEO SARs) to solve the technical challenges including long accumulation time and complex target motion characteristics. The improvement on the existing algorithm mainly involves four aspects. First, the formula for calculating the appropriate time length of subaperture is derived, according to the principle that the accumulated power of the ship’s echo corresponding to the subaperture duration ensures that the signal-to-noise ratio satisfies the requirement of GEO SARs. The derived formula solves the problem that how long the subaperture length should be taken with regards to a long accumulation time of GEO SAR when imaging ships. Second, we propose an optimization criterion for determining the appropriate subaperture time window by ensuring that the maximum number of ship pixels is detected in the subaperture image. The proposed criterion is used to optimize the location of the subaperture time window in the long accumulation time. Third, the SPECAN algorithm used in the scene imaging process is replaced by an improved nonlinear chirp scaling (NLCS) algorithm to improve the imaging accuracy of the scene. Our improvement on the traditional NLCS algorithm focuses on improving precisions of some of the formulas in the traditional algorithm. Furthermore, a translational compensation algorithm is proposed by considering the influence of spatial variance of slant range history of GEO SARs. The proposed translational compensation algorithm improves the compensation accuracy since the spatial variance of different scatterers in the scene is considered. A series of simulation experiments related with ship imaging in GEO SARs were carried out to verify the correctness of the proposed algorithm and the improvement on the imaging quality compared with that of the existing algorithm.

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“…The multiple moving target imaging methods in the traditional SAR system can be classified into two types: the approach based on the image domain [29,30] and the approach based on the echo data domain [31,32]. The typical methods based on the image domain are hybrid SAR/ISAR [33][34][35] and deep learning techniques [36][37][38]. Both of them compensate for the satellite movement using SAR processing and obtain blurred SAR images.…”

Section: Introductionmentioning

confidence: 99%

MosReformer: Reconstruction and Separation of Multiple Moving Targets for Staggered SAR Imaging

Qi,

Zhang,

Jiang

et al. 2023

Remote Sensing

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Maritime moving target imaging using synthetic aperture radar (SAR) demands high resolution and wide swath (HRWS). Using the variable pulse repetition interval (PRI), staggered SAR can achieve seamless HRWS imaging. The reconstruction should be performed since the variable PRI causes echo pulse loss and nonuniformly sampled signals in azimuth, both of which result in spectrum aliasing. The existing reconstruction methods are designed for stationary scenes and have achieved impressive results. However, for moving targets, these methods inevitably introduce reconstruction errors. The target motion coupled with non-uniform sampling aggravates the spectral aliasing and degrades the reconstruction performance. This phenomenon becomes more severe, particularly in scenes involving multiple moving targets, since the distinct motion parameter has its unique effect on spectrum aliasing, resulting in the overlapping of various aliasing effects. Consequently, it becomes difficult to reconstruct and separate the echoes of the multiple moving targets with high precision in staggered mode. To this end, motivated by deep learning, this paper proposes a novel Transformer-based algorithm to image multiple moving targets in a staggered SAR system. The reconstruction and the separation of the multiple moving targets are achieved through a proposed network named MosReFormer (Multiple moving target separation and reconstruction Transformer). Adopting a gated single-head Transformer network with convolution-augmented joint self-attention, the proposed MosReFormer network can mitigate the reconstruction errors and separate the signals of multiple moving targets simultaneously. Simulations and experiments on raw data show that the reconstructed and separated results are close to ideal imaging results which are sampled uniformly in azimuth with constant PRI, verifying the feasibility and effectiveness of the proposed algorithm.

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A Hybrid SAR/ISAR Approach for Refocusing Maritime Moving Targets with the GF-3 SAR Satellite

Cited by 4 publications

References 38 publications

Design of Power Supply System for High Power SAR Satellite

Design of Power Supply System for High Power SAR Satellite

Improved ship imaging algorithm for geosynchronous synthetic aperture radar (SAR) featured by subaperture time window selection optimization and inverse SAR translational compensation

MosReformer: Reconstruction and Separation of Multiple Moving Targets for Staggered SAR Imaging

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