Ship Detection in Dual-Channel ATI-SAR Based on the Notch Filter

Gao, Gui; Shi, Gongtao

doi:10.1109/tgrs.2017.2701810

Cited by 15 publications

(13 citation statements)

References 34 publications

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“…Although most phase differences between channels were compensated for, a residual phase variation over the Doppler frequency was also observed, which implies a residual phase difference. interferometric phase diagram after multiplying by the linear phase compensation factor in Equation (11). In contrast to Figure 3b, the phase variation over the range disappeared, indicating the group-phase shift was eliminated.…”

Section: Channel Registration Results Using the Gotcha Challenge Datasetmentioning

confidence: 85%

“…The residual phase difference varying over the range is clearly visible in Figure 3b. Figure 3c presents the interferometric phase diagram after multiplying by the linear phase compensation factor in Equation (11). In contrast to Figure 3b, the phase variation over the range disappeared, indicating the group-phase shift was eliminated.…”

Section: Channel Registration Results Using the Gotcha Challenge Datasetmentioning

confidence: 94%

“…Recently, GMTI based on a dual-channel SAR data has raised significant interest among researchers because of its advantages in clutter suppression. In Gao and Shi [11], a notch filter was capable of detecting ship targets from the image pairs obtained using a dual-channel ATI-SAR. However, the filter is only suited for ocean applications.…”

Section: Introductionmentioning

confidence: 99%

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Moving Target Indication for Dual-Channel Circular SAR/GMTI Systems

Wang

et al. 2019

Sensors

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In a dual-channel circular synthetic aperture radar (CSAR) and ground moving target indication (GMTI) system, the antenna baseline is not parallel with the flight path due to a yaw angle. The angle causes a varying group-phase shift between the dual-channel signals and therefore degrades the correlation between the image pair. Therefore, the group-phase shift needs to be removed before channel equalization. To resolve the problem, the interferometric phase term was deduced and analyzed based on the geometry of a dual-channel CSAR system. Then, the varying phase term with respect to the Doppler frequency and the varying group-phase shift over the range were compensated for in the channel registration. Furthermore, blind channel equalization, including two-dimensional calibration and amplitude equalization, was applied to eliminate the amplitude and residual phase differences between the channels. Finally, the amplitude image obtained using a displaced phase center antenna (DPCA) was multiplied by the phase image obtained with along-track interferometry (ATI) to detect moving targets. The experimental results verified the effectiveness of the method for both uniform and non-uniform clutter suppression.

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Section: Channel Registration Results Using the Gotcha Challenge Datasetmentioning

confidence: 85%

Section: Channel Registration Results Using the Gotcha Challenge Datasetmentioning

confidence: 94%

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Moving Target Indication for Dual-Channel Circular SAR/GMTI Systems

Wang

et al. 2019

Sensors

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“…Other research revealed that the Radar Cross Section (RCS) of non-metallic vessels (e.g., wooden) is much smaller than comparably-sized metal made ones and a reliable detection with SAR is hard to provide [16,17]. Gao and Shi used Along Track Interferometry (ATI) SAR data to successfully detect small vessels [18]. Recently, deep learning algorithms for small ship detection emerged with the drawback of high computational cost and the need for training data support [19].…”

Section: Vessel Detection Systems: Developments Approaches and Methodsmentioning

confidence: 99%

The InflateSAR Campaign: Testing SAR Vessel Detection Systems for Refugee Rubber Inflatables

Lanz

Marino²,

Brinkhoff³

et al. 2021

Remote Sensing

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Countless numbers of people lost their lives at Europe’s southern borders in recent years in the attempt to cross to Europe in small rubber inflatables. This work examines satellite-based approaches to build up future systems that can automatically detect those boats. We compare the performance of several automatic vessel detectors using real synthetic aperture radar (SAR) data from X-band and C-band sensors on TerraSAR-X and Sentinel-1. The data was collected in an experimental campaign where an empty boat lies on a lake’s surface to analyse the influence of main sensor parameters (incidence angle, polarization mode, spatial resolution) on the detectability of our inflatable. All detectors are implemented with a moving window and use local clutter statistics from the adjacent water surface. Among tested detectors are well-known intensity-based (CA-CFAR), sublook-based (sublook correlation) and polarimetric-based (PWF, PMF, PNF, entropy, symmetry and iDPolRAD) approaches. Additionally, we introduced a new version of the volume detecting iDPolRAD aimed at detecting surface anomalies and compare two approaches to combine the volume and the surface in one algorithm, producing two new highly performing detectors. The results are compared with receiver operating characteristic (ROC) curves, enabling us to compare detectors independently of threshold selection.

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“…Gao proposed a target detection method using polarization notch filter for CFAR detection in heterogeneous sea clutter, which was further extended to the two-channel Along Track Interferometric SAR (ATI-SAR) mode. These methods were able to detect smaller ship targets [23,24]. However, there are currently no dual-channel ATI-SAR satellite data for ship monitoring.…”

Section: Introductionmentioning

confidence: 99%

A Small Ship Target Detection Method Based on Polarimetric SAR

2019

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The detection of small fishing ships is very important for maritime fishery supervision. However, it is difficult to detect small ships using synthetic aperture radar (SAR), due to the weak target scattering and very small number of pixels. Polarimetric synthetic aperture radar (PolSAR) has been widely used in maritime ship detection due to its abundant target scattering information. In the present paper, a new ship detector, named ΛM, is developed based on the analysis of polarization scattering differences between ship and sea, then combined with the two-parameter constant false alarm rate method (TP-CFAR) algorithm to conduct ship detection. The goals of the detector construction are to fully consider the ship’s depolarization effect, and further amplify it through sliding window processing. First, the signal-to-clutter ratio (SCR) enhancement performance of ΛM for ships with different lengths ranging from 8 to 230 m under 90 different combinations of windows are analyzed in detail using three set of RADARSAT-2 quad-polarization data, then the appropriate window size is determined. In addition, the SCR enlargement between ΛM and some typical polarization features is compared. Among these, for ships of length greater than 35 m, the average contrast of ΛM is 33.7 dB, which is 20 dB greater than that of the HV channel. For small vessels of length less than 16 m, the average contrast of ΛM is 16 dB higher than that of HV channel on average. Finally, the RADARSAT-2 data including nonmetallic small vessels are used to perform ship detection tests, and the detection ability for conventional and small ships of some classic algorithms are compared and analyzed. For large vessels of length greater than 35 m, the method proposed in this paper is able to obtain a superior detection result, maintain the ship contour well, and suppress false alarms caused by the cross side lobe in the SAR image. For small vessels of length less than 16 m, the method proposed in this paper can reduce the number of missed targets, while also obtaining superior detection results, especially for small nonmetallic vessels.

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Ship Detection in Dual-Channel ATI-SAR Based on the Notch Filter

Cited by 15 publications

References 34 publications

Moving Target Indication for Dual-Channel Circular SAR/GMTI Systems

Moving Target Indication for Dual-Channel Circular SAR/GMTI Systems

The InflateSAR Campaign: Testing SAR Vessel Detection Systems for Refugee Rubber Inflatables

A Small Ship Target Detection Method Based on Polarimetric SAR

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