Detect and survive

Emergency crews could be given technology to allow them to communicate and locate each other in smoke-filled or partially collapsed buildings, and even detect survivors by their breathing.

The technology, which is based on ultrawideband (UWB) radio, is being developed in an EU-funded project led by Thales Research and Technology in the UK.

In collapsed or fire-stricken buildings, locating and communicating with rescue workers can be extremely difficult, said David Harmer, project co-ordinator and chief engineer at Thales Research and Technology.

‘The key scenario we’re considering is personnel going into damaged or collapsed buildings, or buildings that are on fire. It could also be in the aftermath of a bomb, where the police might want the forensic people to go in, and it would help them to co-ordinate the search if they can see where everyone is and record where they have gone,’ he said.

Credit card-sized ultrawideband transceivers would be attached to the crew members as they enter collapsed or burning buildings, and used to locate them to within around 20cm. The tags could also transmit data such as details on the crew members’ health or that of their equipment, and images of the disaster scene.

The same device could also be used for radar in search and rescue operations, to locate people trapped under rubble by detecting the movement of their chests as they breathe in and out.

Conventional radio frequency technology is unsuitable for tracking people accurately within buildings, as it is affected by multipath distortion, when signals reflect off walls or other objects. But the wider the bandwidth of the signal,  the more accurately it can be timed, meaning that with UWB even if the multipath signals arrive very shortly after the direct signal, they can be filtered out. This precise timing is also what gives the technology its positioning accuracy.

GPS-based systems also tend to be hit by significant problems when used indoors.

The team behind the Emergency Ultrawideband Radio for Positioning and Communications (Europcom) project is using a technique known as frequency hopping to generate the signal, said Harmer.

This involves taking a signal spread over 20MHz and hopping it over 1GHz of spectrum in around a millisecond, effectively creating an ultrawideband signal.

The Office of the Deputy Prime Minister, which is responsible for the fire service, and the Police Information Technology Organisation are on the project’s steering committee.

Discussions with emergency personnel have already raised a number of issues, said Harmer. As fire crews tend to operate in small groups, often at some distance from each other, ensuring enough transceivers are dotted around the building to provide sufficient coverage could be difficult.

So the researchers are investigating the possibility of rescue teams carrying extra transceivers to place at different points as they go through the building.

The police have also expressed an interest in fitting the transceivers to police dogs. In initial feasibility experiments on using the technology for search and rescue operations, the team has been using multistatic radar.

Conventional monostatic radar uses a single antenna to transmit and receive the signal. In contrast, multistatic radar consists of several units, each transmitting a signal, which are reflected off the object and received by a single separate antenna. Combining multiple signals at one receiver means the system is more sensitive.

The e4.2m (£2.9m) project also includes Delft Technical University, the Technical University of Graz and German communications specialist IMST. The team is carrying out the initial system design and will begin work on more detailed designs later this summer. It hopes to hold demonstrations of the technology in 2007.