Fraunhofer FHR scientists have developed a new mobile radar device to search for buried people more quickly and thoroughly.
The new technology can be used to comb hectare-sized areas and could make rescue in avalanches, earthquakes and other disasters more instant than ever before.
Led by Reinhold Herschel, the FHR team’s mobile radar system locates people buried under rubble by detecting their pulse and breathing.
“Our longer-term goal is to mount this radar device on a drone and fly it over the disaster site,” notes Herschel.
“This would make searches faster and more effective even in areas extending over various hectares.”
The new radar device works by emitting waves; part of each wave is reflected by the debris. But some of the wave passes through the rubble and is reflected by people and anything else buried underneath it.
The distance to an object is calculated by measuring how long the signal takes to return to the detector in the radar system.
If that object is moving – even if it is just a buried person’s skin rising and falling by a few hundred micrometers with each heartbeat – this changes the phase of the signal.
The same applies to the tiny movements caused by people’s breathing.
People typically take a breath no more than 10 to 12 times a minute, while the heart beats an average of 60 times a minute.
This makes it relatively simple to distinguish between these different signal changes using algorithms.
The scientists have also developed a special type of radar known as MIMO (multiple input, multiple output).
This can then be used to identify the exact location where paramedics should dig for survivors.
What makes the new radar system all the more unique is its combination of mobility and accurate detection of people’s vital signs.
Though the mobility advantage refers to mounting the device on a drone and flying it over the disaster site, it is also possible to turn this principle on its head.
Set up the system in a fixed spot, and it can be used to detect the vital signs of people moving around close to the radar.
This could prove useful in providing first aid to large numbers of casualties in a sports hall following an earthquake.
For instance, the radar device could be used to record vital signs and assign them to each individual to determine who is in most urgent need of assistance.
Image and content: Patrick Wallrath/Fraunhofer FHR
