Ship detection using Google Earth Pro and SAR Sentinel-1 Satellite in Karimunjawa, Indonesia

Abstract

Karimunjawa is one of the tourist icon due to the beauty of its coral reefs. Many tourists visit for snorkeling and diving in Karimunjawa which requires ships for transportation. This study aims to determine the distribution of ships in Karimunjawa before and during the COVID-19 pandemic using the Google Earth Pro satellite and Synthetic Aperture Radar (SAR) Sentinel-1. There were 6 islands selected to represent the anchorage level based on the number of tourist arrivals. The results of this study indicate that the Sentinel-1 SAR has high capability in detecting ships by using the Constant False Alarm Rate (CFAR) algorithm method, which was detected with a total of 83 ships on 31st March 2021 in six island representatives. This funding is supported by SAR images that have a high spatial resolution of 5m, moreover, ships are typically constructed from large flat metal sheets and hence are usually radar bright and detectable in SAR imagery. Even though Google Earth Pro has a higher resolution of 30 cm, the ship detection process is identified manually. This study showed the Covid-19 pandemic condition had a significant decreasing effect on the number of ships detected, there was a 41.6% decrease from 2019 to 2020 and a 41.95% decrease from 2020 to 2021 due to the temporary closure of Karimunjawa.