Multi-Aperture Focusing in Spaceborne Transmitter-Stationary Receiver Bistatic SAR

Anghel, Andrei; Cacoveanu, Remus; Rommen, Björn; Datcu, Mihai

doi:10.1109/igarss.2019.8900142

Cited by 5 publications

(6 citation statements)

References 9 publications

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“…This property of azimuth compression through fast Fourier transform (FFT) basis along with the assumption of scene spatial sparsity justifies the possibility of the azimuth profile recovery by CS with Fourier sparsifying dictionary. From (7), it may be seen that the longer the multiaperture interval, the higher the range walk effect. Since we aim to process each iso-range profile with CS, an RCMC step is necessary.…”

Section: A Kt-based Rcmcmentioning

confidence: 99%

“…By introducing ( 5) in ( 6) the following linear approximation of the equivalent bistatic range variation is obtained (7):…”

Section: A Kt-based Rcmcmentioning

confidence: 99%

“…As a consequence of the linear approximation in (7), the azimuth bandwidth is extremely narrow. Therefore, the SAR image may be simply obtained by projecting range compressed data along cross-range dimension in the Fourier domain.…”

Section: A Kt-based Rcmcmentioning

confidence: 99%

“…A significant drawback is that most of the bistatic systems have a degraded cross-range resolution as compared to the monostatic systems. Even so, multiaperture data availability leads to the improvement of bistatic imaging [6], [7].…”

Section: Introductionmentioning

confidence: 99%

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A Compressive-Sensing Approach for Opportunistic Bistatic SAR Imaging Enhancement by Harnessing Sparse Multiaperture Data

Focsa

Anghel

Datcu

2022

IEEE Trans. Geosci. Remote Sensing

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This article introduces a compressive sensing (CS)-based approach for increasing bistatic synthetic aperture radar (SAR) imaging quality in the context of a multiaperture acquisition. The analyzed data were recorded over an opportunistic bistatic setup including a stationary ground-based-receiver opportunistic C-band bistatic SAR differential interferometry (COBIS) and Sentinel-1 C-band transmitter. Since the terrain observation by progressive scans (TOPS) mode is operated, the receiver can record synchronization pulses and echoed signals from the scene during many apertures. Hence, it is possible to improve the azimuth resolution by exploiting the multiaperture data. The recorded data are not contiguous and a naive integration of the chopped azimuth phase history would generate undesired grating lobes. The proposed processing scheme exploits the natural sparsity characterizing the illuminated scene. For azimuth profiles recovery greedy, convex, and nonconvex CS solvers are analyzed. The sparsifying basis/dictionary is constructed using the synthetically generated azimuth chirp derived considering Sentinel-1 orbital parameters and COBIS position. The chirped-based CS performance is further put in contrast with a Fourier-based CS method and an autoregressive model for signal reconstruction in terms of scene extent limitations and phase restoration efficiency. Furthermore, the analysis of different receiver-looking scenarios conducted to the insertion in the processing chain of a direct and an inverse Keystone transform for range cell migration (RCM) correction to cope with squinted geometries. We provide an extensive set of simulated and real-world results that prove the proposed workflow is efficient both in improving the azimuth resolution and in mitigating the sidelobes.

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Section: A Kt-based Rcmcmentioning

confidence: 99%

“…By introducing ( 5) in ( 6) the following linear approximation of the equivalent bistatic range variation is obtained (7):…”

Section: A Kt-based Rcmcmentioning

confidence: 99%

Section: A Kt-based Rcmcmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Compressive-Sensing Approach for Opportunistic Bistatic SAR Imaging Enhancement by Harnessing Sparse Multiaperture Data

Focsa

Anghel

Datcu

2022

IEEE Trans. Geosci. Remote Sensing

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“…To avoid this effect, the next step is to fill the gaps between the apertures using an AR model [6]. An analysis was done in [7] describing the negative effects of these gaps.…”

Section: B)mentioning

confidence: 99%

Multiaperture Focusing for Spaceborne Transmitter/Ground-Based Receiver Bistatic SAR

Rosu

Anghel

Cacoveanu³

et al. 2020

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

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The paper proposes a methodology to perform azimuth focusing of spaceborne transmitter-stationary receiver bistatic synthetic aperture radar (SAR) data across multiple along-track apertures to increase azimuth resolution. The procedure uses as input several azimuth apertures (continuous groups of range compressed pulses) from one or more satellite bursts and comprises the following stages: antenna pattern compensation, slow time resampling, reconstruction of missing azimuth samples between neighboring sets of pulses using an auto-regressive (AR) model and back-projection focusing of the resulting multi-aperture range image. A novel, highly efficient method is proposed to estimate the optimal order for the AR model. It differs from the traditional approach that uses the Akaike Information Criterion to directly estimate the order, because the proposed method estimates the order indirectly by detecting the number of targets using principle component analysis. Spatial Smoothing is used to obtain a full rank Covariance matrix, whose eigen values are then analyzed using Minimum Description Length. The optimal order is an integer multiple of the number of targets, which depends on SNR. The approach is evaluated with real bistatic data acquired over an area of Bucharest city, Romania.

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Stable Scatterer Detection in Multi-Aperture Spaceborne-TX / Ground based-RX Bistatic SAR

Rosu

Anghel

Cacoveanu³

et al. 2021

Procedia Computer Science

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Multi-Aperture Focusing in Spaceborne Transmitter-Stationary Receiver Bistatic SAR

Cited by 5 publications

References 9 publications

A Compressive-Sensing Approach for Opportunistic Bistatic SAR Imaging Enhancement by Harnessing Sparse Multiaperture Data

A Compressive-Sensing Approach for Opportunistic Bistatic SAR Imaging Enhancement by Harnessing Sparse Multiaperture Data

Multiaperture Focusing for Spaceborne Transmitter/Ground-Based Receiver Bistatic SAR

Stable Scatterer Detection in Multi-Aperture Spaceborne-TX / Ground based-RX Bistatic SAR

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