Geophysical exploration from space and the air (Remote sensing and drone geophysical surveys)

Abstract

　This article discusses the topic of "geophysical exploration from space and the air (remote sensing and drone geophysical exploration)."

　First, in terms of trends in satellite remote sensing, the rise of small commercial satellites, the construction of satellite constellations, and satellite-related programs in Japan is discussed. This is due to the development of small optical and SAR (Synthetic Aperture Radar) satellites, and the construction of satellite constellations. These advancements indicate that in the near future, constant observation of the entire world will be possible. Next, as examples of remote sensing applications, we introduce SAR applications in the fields of disaster prevention and civil engineering. These technologies enable the quick extraction of inundation information during flooding events, the possibility of detecting landslide disasters in advance, and the enhancement of efficiency in the maintenance and management of road structures.

　Drone geophysical surveying is particularly utilized in the civil engineering field, supported by the Ministry of Land, Infrastructure, Transport, and Tourism's i-Construction initiative. While there are many examples of UAV surveying (LiDAR and LP) in the civil engineering field, airborne electromagnetic surveying is common in the geophysical exploration community. Drones are also employed in underwater exploration as Autonomous underwater vehicles (AUVs). As examples of drone geophysical survey applications, we introduce an investigation of the collapse mechanism of a collapsed slope caused by a typhoon using airborne electromagnetic survey by a drone, and a river patrol demonstration experiment using a VTOL aircraft.

　Looking ahead, satellite remote sensing is expected to feature higher resolution sensors, more frequent observations by satellite constellations, and improved real-time data provision. Drone geophysical surveys are expected to be applied to various geophysical survey methods as the technological development of observation equipment progresses. These advancements are expected to be useful for rapid response to disasters and infrastructure monitoring during peacetime.