Detection of forest fires using IR image sensors

Fire: A powerful and at the same time dangerous element for nature and all living creatures. The Munich startup OroraTech has the mission to detect forest fires globally, quickly and reliable using satellite technology. This enables forest and bush fires in sparsely populated areas such as Canada or Australia to be detected earlier from space and prevents the fires from getting out of control. OroraTech already has a platform in operation that processes available satellite data and is used by Australian customers for example for monitoring "bushfires". In order to be able to detect fires even faster and more reliable, the start-up is developing its own small satellites with a special thermal infrared camera, which will be launched into earth orbit at the end of 2021.

There is a close cooperation between the Fraunhofer IMS and the company OroraTech. Fraunhofer IMS supplies an IR image sensor (IRFPA = infrared focal plane array) with an optical resolution of 320 x 256 pixels (digital 17 µm QVGA-IRFPA). The IR image sensors of Fraunhofer IMS are characterized by their high temperature sensitivity (NETD < 60 mK) over a dynamic range (ΔTScene > 300 K). Furthermore, they are sensitive for the long-wave (wavelength 8 - 14 µm, LWIR) as well as for the mid-infrared range (wavelength 3 - 5 µm, MWIR). The innovative readout circuit provides digital video signals with a resolution of 16 bit and enables different operating modes, so that applications from thermal standard image acquisition to the realization of an infrared line sensor are supported.

The digital 17 µm QVGA-IRFPA of the Fraunhofer IMS as IR image sensor is the heart of a thermal infrared camera developed by Ororatech especially for fire detection from space. The prototype of this camera is already completed and should be able to withstand the space conditions prevailing on a satellite. To test the performance of the prototype, the camera was mounted on a drone for this purpose. Various heat sources were set up on the ground, to which the camera system was directed from a height of more than 400 m. A surface heated up to 350°C of the size of just one third of a beer mat could be detected (see pictures 1 and 2). With this convincing performance, it is expected that the camera will be able to detect fires from space all over the world immediately after their formation. In the final expansion phase, the satellite-supported early warning system should be able to report the outbreak of a fire within app. 30 minutes.