RAVEN – Remote Airborne Variable Emissivity and Temperature SeNsor

Climate change results in more frequent and more intense heatwaves. This affects urban areas in particular, as they trap the heat and become what is known as urban heat islands (UHIs). In order to develop effective adaptation strategies, detailed monitoring of heat accumulations in cities and an understanding of their interactions with the environment are essential.

The required data can be provided through radiometric long-wave infrared (LWIR) remote sensing. The LWIR range distinguishes itself by not relying on the reflection of radiation from a secondary source for imaging. Instead, it measures the emitted thermal radiation of the objects being imaged, providing a contrast independent of the sun’s position and allowing inference of the object’s temperature. When using multiple narrow bands, inference about the nature of the emitting surface becomes possible.

However, urban areas exhibit highly heterogeneous surface types that are not adequately addressed by satellite observations or generic broadband LWIR cameras.

RAVEN was developed to bridge this gap. RAVEN („Remote Airborne Variable Emissivity and Temperature SeNsor“) is an instrument for airborne remote sensing, specifically tailored to the requirements of urban environments and ambient temperatures. RAVEN utilises off-the-shelf hardware to provide high-resolution LWIR images in three calibrated spectral bands. This allows for the simultaneous estimation of surface properties (spectral emissivity) and the corrected surface temperature. The required radiometric accuracy is achieved through a robust calibration approach and an additively manufactured housing with active temperature stabilisation.

RAVEN is engineered for use on various airborne platforms.

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