Identifying Ships in Lembeh Strait based on Pi-SAR L-2 Airborne Campaign

摘要

Synthetic Aperture Radar (SAR) is one of the most promising satellite or airborne remote sensing sensor for monitoring of the earth surface at a regional to global scale. SAR has many useful characteristics for various applications, such as cloud-free and day-night observation capability, highly spatial resolution produced by the synthetic aperture technique, and polarimetric and interferometric information. In particular, cloud-free observation by SAR is a huge advantage for monitoring of humid tropical regions such as Indonesia. SAR is one technique in radar remote sensing that can be utilized for marine applications such as surface waves monitoring, ocean current circulation detection, oil slick monitoring and ship detection. In order to assess the ability of SAR technique for ship detection, we analyze SAR data acquired by full polarimetric and interferometric airborne SAR in L-band type-2 (Pi-SAR-L2) from Japan Aerospace Exploration Agency QAXA). This research explains the strategy in SAR data processing for ship detection application in Lembeh Strait, North Sulawesi Sea. It is found that long wavelength i.e. L-band is able to identify ships on the sea with incidence angle of radar beam greater then 50 degree gives the best signal clutter ratio between signal from the ship to sea clutter variation. The ship-sea contrast is more clearly at HH-polarized then VV-polarized due to the increased scatter at W-polarized by the surface capillary waves. The identification includes the size estimation and the location. It is also found that by combining SAR data with VMS (Vessel Monitoring System) data it is possible to identify ships without VMS and useful for improving security issue in fisheries sector. VMS data is for monitoring authorized fishing vessels and Pi-SAR data detect vessels not reporting through VMS.