Most abandoned luggage items turn out to be harmless. But in the first instance the emergency services have to proceed on the assumption of possible danger and check whether they are dealing with an improvised explosive device (IED) that might blow up at any time. This involves getting up close to the luggage to inspect it. The system will make it possible to assess the danger of the situation quickly – it also records 3D images of the contents and shape of the luggage as well as of the surrounding area –making the specialists’ work easier, speeding the reconnaissance process, and minimising the risk for the emergency personnel.
The system the researchers have developed comprises a multimodal sensor suite consisting of a millimetre wave scanner, a high-resolution digital camera, and a 3D environment monitoring system. The components are contained in a housing mounted on a robot platform. Bomb disposal engineers remotely control the robot from a safe distance.
Stefan Lang, team leader at the FHR and the project’s coordinator, explained: “Up to now our techniques have not allowed us to form a 3D outline of suitcase bombs, and it has been impossible – or only partially possible – to make a spatial map of the contents. With the sensor suite we can visualise in three dimensions what’s inside a luggage item, and so determine the composition of the bomb and how the parts are arranged in the luggage.” This lets the explosives experts quickly assess the threat, and going forward they will also be able to preserve as much evidence as possible about the bomb. Until now, specialists were often forced to destroy suitcase bombs – making it difficult to identify the perpetrators.
The Fraunhofer researchers are developing the millimetre wave scanner for fast reconnaissance. This scanner allows a very high depth resolution. “For the radar we make use of the synthetic aperture radar, or SAR, principle, by which the sensor is moved along a trajectory, a kind of track – from left to right in front of the case, for example – and the Doppler information generated in the process is used to create an image,” Lang continued. Apart from the research work on the sensor, the team is also looking into ways of determining the optimum trajectory for surveying an object.
