Unmanned systems such as UAVs (unmanned aerial vehicles), USVs (unmanned surface vessels) and AUVs (autonomous underwater vehicles) can be equipped with a variety of different sensors that allow them to undertake environmental research and monitoring applications.
UAVs may carry high-resolution cameras that allow them to capture imagery of the landscape and monitor how terrain features such as rivers and glaciers are affected by man-made and natural processes. These UAV cameras may also be used to track and monitor wildlife populations. Thermal cameras are also highly useful for counting animal populations, as the temperature is recorded in the data and this allows thermal imaging software to easily filter out objects that may be living creatures.
Multispectral sensors allow UAVs to monitor plants and crops, as the amount of infrared reflected back by leaves provides a good indicator of health. Multispectral remote sensing can be used to monitor hydration, pest incidence levels, and other factors.
Synthetic aperture radar (SAR), which uses radio or microwave pulses to provide imaging capabilities, is often used for environmental monitoring applications that require trend analysis and change detection, such as forestry and population detection. It is also useful for oil spill detection, as the presence of oil on the surface of water changes the radar backscatter, causing the oil to show up on images as a darker color.
USVs can carry water and sediment sampling equipment, as well as sensors that can analyze water to determine factors such as temperature, pH, conductivity and salinity. These capabilities are useful for pollution monitoring and marine biodiversity.
AUVs and other UUVs (unmanned underwater vehicles) can also be used to sample and test water, and may also carry hydrophones for underwater noise pollution measurement and marine mammal tracking. They may also use bathymetric sonar to map sea and lake beds and assess underwater terrain for factors such as erosion and sedimentation, as well as to predict tides and currents and study the impact of climate change.