According to a study by the Karlsruhe Institute of Technology (KIT), between 1900 and 2015 around 2, 32 million people worldwide died due to earthquakes alone. Other disasters that cause houses to collapse, for example, are not yet taken into account.

Many of these people could have been saved – but that would require emergency services know where exactly the living can be found, i.e. under which heaps of earth and rubble they have to look. The Fraunhofer Institute for High Frequency Physics and Radar Technology (FHR) in Wachtberg is working on a new mobile technology that uses electromagnetic radar waves to precisely locate buried people.

The drone searches for vital signs The waves can partially penetrate debris, so that signals from the buried subjects are sent back to the detector of the radar device. The type of feedback tells how far away the buried person is. So-called MIMO radars (Multiple Input Multiple Output Antennas) have several transmitters and receivers. This way, different perspectives can be brought together like a mosaic, which provide information about the exact location of the burial.

Similar technology is already in use, but stationary and only with one range of a maximum of 30 meters. With the new approach, hectare-sized areas can be searched in future that meet the requirements of a real disaster. “We have developed a mobile radar device that can determine the pulse and breathing of buried people and thus locate them,” says FHR team leader Reinhold Herschel. “In the long term, a drone equipped with a radar device could fly over the scene of the accident.”

Two scenarios The technology should not only serve to find victims with mobile drones. It is also able to record the exact signs of life of the injured who are in the area of ​​operation. This can be helpful in prioritizing first aid if numerous injured people need help at the same time. Thanks to machine learning, critical states can be differentiated more quickly from stable ones. Due to different rhythmic frequencies, they should be able to tell vital signs apart. This is how you know your regular heartbeat and breathing. If they are changed, you can intervene. Test runs have already shown that precise vital signs can be successfully measured at a distance of up to 15 meters. In order to be recorded, people only have to move a little, it is enough to breathe.

It will be a little more complex with the detection itself: Another two years will be researched into how people buried in the ground and Concrete can be reliably determined and how drones can take over this measurement. Commercialization is also conceivable. (bsc)