Development of a UAV-mounted Imaging FTIR for real-time monitoring of natural and anthropogenic hazards

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Natural hazards are characterised by the large area affected, rapidly changing scale and extent of the effects, and severe disruption to access and communication to the affected areas. During and after the onset of a natural disaster an accurate and immediate assessment of the extent and severity of the effects of the event is critical in order to assist the deployment of emergency services and to implement an effective mitigation strategy. The assessment requirement for anthropogenic hazards differs in that the location and spatial extent of the facility is known and is usually relatively restricted. The requirement for monitoring is therefore for high spatial and temporal resolution monitoring over extended periods over often highly complex infrastructure which can often be elevated 10s of metres off the ground. Acquisition of sampling datasets with the essential 2 and 3D spatial and temporal resolution and detection sensitivity to address the requirements of the emergency services, regulatory agencies and commercial users is a significant monitoring challenge and poses a critical market need. A diverse range of researchers, interest groups, commercial and emergency and regulatory organisations require the detection, quantification and differentiation of surface gas releases at spatial scales ranging from point source to landscape scale. Identification of the sources and fluxes of fugitive releases of hydrocarbon gas is a critical component of a number of emergency and commercial monitoring strategies. Biogenic gas is composed almost entirely of methane whereas thermogenic (natural) hydrocarbon gas is composed of a mixture of methane, propane, butane and ethane. Gas emissions from landfill sites are a common environmental issue faced by councils and the environment agency while fugitive emissions from pipelines are a very expensive and inconvenient problem for many commercial organisations ranging from domestic supply to large-scale petro-chemical facilities.Current methods to meet these challenges are still largely ground-based and manual. While ground-based methods are locally highly effective the limitation in the coverage of observations can often result in a poor understanding of the nature and extent of the hazard resulting in less effective containment and response strategies producing more severe and longer lasting effects. Remote-sensed based approaches have been implemented using a range of sensors and platforms however their operational utility has been severely limited as they cannot derive the most important physical parameters required for hazard monitoring (surface temperature and especially gas species identification and quantification) at the necessary ultra-high spatial resolution in real-time.There is an urgent need for the development of a low-cost, rugged, low mass, imaging system that can be mounted on a UAV that has the capability to detect and differentiate fugitive gas escapes and resolve surface temperature accurately. Currently available imaging based gas monitoring instruments are not capable of resolving the hydrocarbon gases with sufficient accuracy. Imaging Fourier Transform Interferometers (FTIRs) have the potential to detect and quantify hydrocarbon emissions but the current design of imaging FTIRs have a very high power consumption, are very heavy and are prohibitively expensive for operational deployment on a UAV. The aim of this project is to develop, and validate a low cost, lightweight, compact imaging Fourier Transform InfraRed (FTIR) spectrometer that can be operational mounted on a UAV that has sufficient spectral resolution and radiometric sensitivity to detect and quantify fugitive gas escapes. The ability to extract the spectral emissivity and surface temperature measurements will enable the surface temperature to be resolved much more accurately and emission spectra images will enable the presence of humans and identification of infrastructure more accurately .