Natural disasters are an increasingly serious threat for civil society. A fast and effective disaster management crucially depends on the availability of latest information and overviews of the affected areas. In cooperation with I.S.A.R. Germany we’re developing an autonomous rapid mapping solution that is particularly designed for real-time application, where comparatively large areas have to be assessed in short time by INSARAG certified search and rescue teams. The development is based on DLR’s Modular Aerial Camera System (MACS) and is funded by DLR's security research program.
MACS-SaR rapid mapping camera integrated into a vertical take-off and landing UAV of Germandrones GmbH (Photo by Stefan Sobotta, I.S.A.R. Germany).
Example of instantaneous mapped disaster site with 700x400m in dimension. Mapping time was less 2 minutes by flight altitude of 200m above ground level. Ground resolution is 3cm for each pixel. Figure shows a recreated disaster site of federal swiss army which is located in Epeisses, Switzerland.
A lightweight version of MACS is carried by a vertical take-off and landing (VTOL) fixed wing UAV for generating high-resolution map projected overviews during flight if data link is available or within minutes after landing. The aerial imaging system consists of a nadir looking metric camera, a GNSS receiver in combination with an industrial grade inertial measurement unit (IMU) and an embedded computing board with exchangeable CFast storage module. For every aerial image precise exterior orientation information is known (e.g. time, position and attitude) up to an exposure rate of 3fps (RAW). The rapid mapping process is based on spatial intersection of image rays (i.e. rays of its corresponding pinhole camera in space) and elevation model. For every single aerial image its interior and exterior orientation and optionally boresight alignment determines exactly each pixel’s ray in space. In order to draw an aerial image onto a scaled map (i.e. a geo-referenced coordinate system) a projective mapping for every single image is determined. The result is a scaled image mosaic that shows the current situation of the disaster affected area which serves as additional map layer for common geographic information systems like ArcGIS™, QGis™ and GoogleEarth™.
The first prototype of the rapid mapping solution was evaluated within an international disaster rehearsal led by the United Nations in May 2017. After a major earthquake of magnitude 7.5 on the Richter scale several villages located within 20 kilometers around the epicenter had suffered extensive damage. As in real-life situation, the extent of damage to infrastructures and the number of casualties were initially uncertain. Several scattered areas were mapped in the beginning of the exercise resulting in coverage of 5 square kilometers within the first day. The resulting maps and single aerial images were additionally used for the disaster assessment by I.S.A.R. Germany to identify affected areas, estimate the level of destroyed buildings, recommend secure helicopter landing spots and bivouac sites and recognize remaining overtures to those areas. All maps were shared with other participating search and rescue teams (I.S.A.R. Germany, THW SEEBA, Swiss Rescue and @Fire) due to the On-Site Operations Coordination Centre (OSOCC) and Global Disaster Alert and Coordination System (GDACS). The Songbird UAV by Germandrones was chosen as carrier for the aerial camera system. It provides a fully autonomous on-site operation and thus flights even beyond line of sight. The maximum take-off weight is less 8kg by a net operation time of 60 minutes and an average cruise speed of 80km/h. Due to law restrictions the altitude was limited to 350m above ground level and only flights during daylight within line of sight were permitted.
I.S.A.R. Germany (International Search and Rescue) is a non-profit aid organization founded in Duisburg in 2003. It gathers a team of search and rescue specialists short after devastating accidents and catastrophes, which in most cases is deployed to the disaster affected area within 12 hours. The rescue team searches for trapped people and provides emergency medical services following severe earthquakes and floods. I.S.A.R. Germany has been working under the umbrella of the United Nations since 2007 and was the world's first group to be verified and certified as a 'Medium Team' by the UN Organization INSARAG.
DLR's security research program plans and controls all research and development activities relevant to defense and security in coordination with its partners in government, science, industry and international organizations. In this respect, the cross-sectoral field of security research unites core competencies from established DLR program in aeronautics, space, energy and transport. In total, over 20 DLR institutes and centers pursuing security-relevant work contribute to the development, testing and assessment of technologies, systems and concepts, as well as the analysis and evaluation of their capabilities for security-relevant applications.