FLAIR project targets toxic gas detection

A European project is developing a UAS that uses photonics to detect toxic gases in the atmosphere following events such as wildfires, chemical explosions and volcanic eruptions.

The FLying ultrA-broadband single-shot Infra-Red sensor (FLAIR) project aims to provide real-time air quality data to support quick decision-making during evacuations and the deployment of rapid response emergency services.

The project, led by Portugal’s Tekever Autonomous Systems, is being carried out with partners from Sweden, Denmark, Spain, the Netherlands and Switzerland. The project is expected to deliver a prototype in 2018.

The UAS will be able to reach speeds of 120km/h and cover a radius of 80km. It will feature a novel photonic sensor payload that can simultaneously detect dozens of toxic gasses, including carbon dioxide, methane, sulphur oxides and nitrogen dioxide.

The system works by beaming the sampled air in a ‘multipass cell’ to increase the total optical path length for exposure with a super-continuum laser, allowing the tiniest concentrations of complex, toxic gas mixtures to be detected. The gas concentrations are measured by reading the frequencies or ‘signatures’ of the air sample that become absorbed and ‘dimmed’ in the laser light. To improve detection, these frequencies of the multiple gases are separated. The light then passes through a series of gratings and lenses, illuminating the surface of a multi-pixel detector which is able to distinguish particles at the photon level. From these separated pixels the system can then detect exactly ‘what’ and ‘how much’ of the poisonous gas is present. The UAS then relays this microscopic information to the user on the ground in real time.

André Oliveira, project coordinator of Tekever Autonomous Systems, said: ‘For the first time a gas sensing device has been created from the hybrid of an optical spectrometer and a high-resolution spectroscopy gas sensor. By employing infra-red absorption spectroscopy in either the 2-5 microns or 8-12 microns wavelength windows where most of the harmful gasses have absorption signatures, the optical sensors can detect many molecules, simultaneously in real time.

‘Immediate detection with such accuracy and precision, without putting lives at risk allows us to visualise vast areas of danger more effectively. A tailored response can therefore be deployed to disaster situations, reducing damage or even saving lives.’