Passive coherent multistatic SAR using spaceborne illuminators

Nithirochananont, Ussanai; Antoniou, Michail; Cherniakov, M.

doi:10.1049/iet-rsn.2019.0425

Cited by 11 publications

(7 citation statements)

References 40 publications

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“…There have been similar studies to increase the resolution through spectral synthesis for spaceborne and airborne distributed SAR systems operating in the microwave band. Among these works, the images acquired with slightly different viewing angles are coherently combined to increase the range bandwidth based on the spectral shift principle, and thus, the range resolution of a distributed SAR is improved [28][29][30][31][32][33][34][35]. This paper draws on the core idea of range resolution improvement algorithms of spaceborne and airborne SAR images and focuses on improving the azimuth resolution of the distributed shipborne HFHSSWR system by spectral synthesis.…”

Section: Introductionmentioning

confidence: 99%

Azimuth Resolution Improvement and Target Parameters Inversion for Distributed Shipborne High Frequency Hybrid Sky-Surface Wave Radar

et al. 2021

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In this paper, the aperture synthesis processing techniques for the distributed shipborne high frequency hybrid sky-surface wave radar (HFHSSWR) are proposed to improve the azimuth resolution and obtain the velocity vector and the azimuth estimation of the moving target. First, the system geometry and the signal model of the moving target for the distributed shipborne HFHSSWR are formulated, and then the azimuth resolution improvement principle is derived. Second, based on the developed signal model, we propose an azimuth resolution improvement algorithm, which can obtain the synthetic azimuth bandwidth and an improved resolution using sub-band combination. Finally, a target parameters inversion method is introduced to estimate the target velocity vector and the target azimuth, by solving the equations regarding the target geometry and echo signal parameters numerically. The simulations are performed to verify the proposed algorithms. The results indicate that the distributed synthetic aperture techniques effectively improve the azimuth resolution of this radar, and can obtain the target velocity vector and the high-precision estimation of the target azimuth.

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Section: Introductionmentioning

confidence: 99%

Azimuth Resolution Improvement and Target Parameters Inversion for Distributed Shipborne High Frequency Hybrid Sky-Surface Wave Radar

et al. 2021

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“…where t i_nu is the numeric PSP. The difference between (10) and ( 9) is the signal model error, which is shown as:…”

Section: Signal Model Errormentioning

confidence: 99%

“…Originating from synthetic aperture radar (SAR) [1][2][3][4][5][6][7][8][9][10], synthetic aperture sonar (SAS) [11][12][13][14][15][16] attracts investigators' interests due to its high resolution in the underwater field. Nowadays, it is widely applied to underwater mapping [14,15,17,18], target recognition [19][20][21][22], and so on.…”

Section: Introductionmentioning

confidence: 99%

An Improved Imaging Algorithm for Multi-Receiver SAS System with Wide-Bandwidth Signal

Zhang

Yang²

2021

Remote Sensing

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When the multi-receiver synthetic aperture sonar (SAS) works with a wide-bandwidth signal, the performance of the range-Doppler (R-D) algorithm is seriously affected by two approximation errors, i.e., point target reference spectrum (PTRS) error and residual quadratic coupling error. The former is generated by approximating the PTRS with the second-order term in terms of the instantaneous frequency. The latter is caused by neglecting the cross-track variance of secondary range compression (SRC). In order to improve the imaging performance in the case of wide-bandwidth signals, an improved R-D algorithm is proposed in this paper. With our method, the multi-receiver SAS data is first preprocessed based on the phase center approximation (PCA) method, and the monostatic equivalent data are obtained. Then several sub-blocks are generated in the cross-track dimension. Within each sub-block, the PTRS error and residual quadratic coupling error based on the center range of each sub-block are compensated. After this operation, all sub-blocks are coerced into a new signal, which is free of both approximation errors. Consequently, this new data is used as the input of the traditional R-D algorithm. The processing results of simulated data and real data show that the traditional R-D algorithm is just suitable for an SAS system with a narrow-bandwidth signal. The imaging performance would be seriously distorted when it is applied to an SAS system with a wide-bandwidth signal. Based on the presented method, the SAS data in both cases can be well processed. The imaging performance of the presented method is nearly identical to that of the back-projection (BP) algorithm.

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“…Loffeld et al have deduced a new point target reference spectrum (PTRS) [14]. Using the method of stationary phase [15], the points of stationary phase corresponding to transmitter and receiver phase histories are first deduced. Then, the transmitter and receiver phase histories are expanded in second‐order Taylor series around their individual points of stationary phase.…”

Section: Introductionmentioning

confidence: 99%

Efficient imaging method for multireceiver SAS

Zhang

Yang²,

Feng

et al. 2022

IET Radar Sonar & Navi

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With the Loffeld's bistatic formula, the point target reference spectrum (PTRS) of multireceiver synthetic aperture sonar (SAS) can be decomposed into the quasi monostatic term and bistatic deformation (BD) term. The former term is analogous to the monostatic SAS PTRS while the latter one describes the bistatic phase introduced by the bistatic displacement between the transmitter and receiver. The multireceiver SAS echo signal can be transformed into monostatic SAS equivalent data after correcting the BD term. Based on the range sub-block processing method, this data transformation is conducted by using the preprocessing step. Then, fast imaging processors based on monostatic SAS system can be directly exploited to process the monostatic SAS equivalent data. In this paper, the authors mainly focus on the application of non-linear chirp scaling algorithm. At last, the simulations and real data are used to validate the presented method. The processing results show that the imaging performance of presented method is nearly close to that of traditional method. Besides, the imaging efficiency is highly improved compared to the phase centre approximation (PCA) method.

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Passive coherent multistatic SAR using spaceborne illuminators

Cited by 11 publications

References 40 publications

Azimuth Resolution Improvement and Target Parameters Inversion for Distributed Shipborne High Frequency Hybrid Sky-Surface Wave Radar

Azimuth Resolution Improvement and Target Parameters Inversion for Distributed Shipborne High Frequency Hybrid Sky-Surface Wave Radar

An Improved Imaging Algorithm for Multi-Receiver SAS System with Wide-Bandwidth Signal

Efficient imaging method for multireceiver SAS

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