Remote Sensing with an Unmanned Aerial Vehicle (UAV)
Introduction
Up-to-date and accurate spatial data are of crucial importance for sustainable management of our ecosystems. Satellite imagery provides advanced and efficient means to map the environment at a range of scale levels (global to regional) and quantify environmental changes. The use of very high resolution (VHR) satellite sensors offers significant advantages for vegetation mapping, such as the availability of fine scale multispectral images (60 cm resolution) covering relatively large areas. However, in many applications it is important to obtain additional and more detailed information on terrain elevation and vegetation structure/health. Current satellite and airborne sensors do not offer this level of detail.
UAV
We are currently working on a novel multi-disciplinary project that will develop a remote sensing system for high-resolution vegetation mapping and monitoring. The system, also known as an unmanned aerial vehicle (UAV), consists of a remote controller helicopter carrying two cameras (visible and near-infrared) and an airborne laser scanner (LiDAR). 
These sensors will allow us to map the environment in greater spatial detail than any other remote sensing system (such as aerial photography or satellite imagery). One of the novel aspects of this project is that the UAV will simultaneously collect laser scanning data (LiDAR), visible photography, and infrared photography. The laser scanner will allow us to derive a very detailed digital elevation model (DEM) of the terrain. With this DEM we can model scenarios of sea level rise and their impact on ecosystems for example. Furthermore, the system will acquire information on vegetation height and map vegetation communities based on a combination of imagery and height information. The proposed UAV will allow us to map local areas (several km2) in great spatial detail (centimetre to decimetre resolution) covering the spatial scale levels in between satellite imagery and aerial photography (relatively coarse but large spatial extent) and field observations (very detailed, but confined to small samples or plots). This novel remote sensing platform can be used for a wide range of mapping and monitoring applications, such as vegetation mapping, precision agriculture, viticulture (frost and vigour mapping), coastal morphology (beach and dune profiles), landslide mapping, forestry, power line scanning, mining, etc.
Science question
One of the key scientific questions this system will allow us to explore is: “How does the information content in imagery and LiDAR data change over a range of spatial scale levels and what measures (texture, spectral, structural) can be used to characterise, map, and monitor the environment at these different scale levels?”. In addition to generating improved mapping and monitoring techniques, the answers to these questions will also provide us with a better understanding of the information content in satellite imagery and it will improve our understanding of the relationship between information in satellite imagery and the natural environment.
Aerial photograph of a saltmarsh in southeast Tasmania acquired with a digital camera from the remote controlled helicopter shown above. The orange cones are witches hats placed approximately 20 m apart.
Case studies
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Developing a multi-sensor UAV
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Mapping salt marsh communities in southeast Tasmania
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Mapping moss beds in Antarctica