Analysis of ship size detectability over different TerraSAR-X modes

Abstract

A growing interest in global maritime surveillance has motivated the development of new methods and sensors to overcome the limitations of coastal-based systems coverage. Among the available state of the art tools, the Synthetic Aperture Radar (SAR) stands out as a powerful sensor for oceanographic observation and maritime surveillance, due to its capability of wide swath coverage and the ability to operate in all weather conditions. This paper examines the minimum ship size detectable by the Constant False Alarm Rate (CFAR) algorithm over different TerraSAR-X product modes, using simulation-based analyses. These analyses allow a comparison of the expected CFAR ship detection performance for different TerraSAR-X products, over different sea state conditions.

Ship-Iceberg Detection and Classification in Sentinel-1 SAR Images

“…Finally, ship lengths and breadths in S1 data are analysed and compared to AIS ground truth numbers. These results are also compared to earlier TerraSAR-X [4,5], S1 [9][10], Envisat [11], and S2 multispectral results [12][13].…”

“…The orbital periods are 6 days between the Sentinel-1 (S1) satellites A + B, and 5 days between the Sentinel-2 (S2) satellites A + B. Furthermore, the swaths from different satellite orbits overlap at higher latitudes, and the resulting frequent transits over the polar regions make these satellites particularly useful for Artic surveillance and for monitoring sea-ice coverage, icebergs and ships in SAR [2][3][4][5][6][7][8][9][10][11] and multispectral images (see [12][13] and refs. therein), etc.…”

“…Ship and iceberg detection in SAR imagery has recently been studied in detail for earlier satellites and TerraSAR-X [2][3][4][5][6][7][8] and Sentinel-1 [9][10]. Their different modes and resolutions lead to interesting differences for the ship detection lengths [5,6,10,11], classification in comparison to AIS and false alarm rates [2][3][4][5][6][7][8][9][10][11], etc. A comparison to these results will be made in the conclusion of this work.…”

Modelling ship detectability depending on TerraSAR-X-derived metocean parameters

“…The simulation model used in this analysis is based on the settings and assumptions of the established procedure proposed by Vachon et al for diverse C-band SAR satellites [25][26][27][28], where the sea clutter is modelled using the K-distribution and the target is assumed to follow the Swerling Type III fluctuation model [29]. Inspired by the initial results obtained for X-band SAR satellite images in [30,31], a simulation model based on a larger dataset, i.e. the one described in Sect.…”

Performance Analysis of Time-Frequency Technique for the Detection of Small Ships in SAR Imagery at Large Grazing Angle and Moderate Metocean Conditions

“…An open-ended question in SAR ship detection is the minimum detectable ship size, which is often simplified with the minimum ship length. There are three different approaches that have been used in the literature: 1) in [1]- [3] a semi-empirical prediction mode has been developed merging an ocean radar backscatter geophysical model function (GMF) model and fitting a function between the physical parameter ship length and the measured maximum radar cross section (RCS) of several ship samples; 2) in [4] a binary classifier trained using detected and nondetected ships samples in real TerraSAR-X (TS-X) SAR data, has been used to develop a data-driven ship detectability model; 3) in [5] a direct observation method has been employed by visual interpretation of very high resolution (VHR) SAR imagery over predefined test sites where small boats were deployed. All the three approaches agree that using the radar backscatter information the minimum ship length strongly decreases either with increasing wind speed and decreasing incidence angle.…”