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Multispectral, LIDAR & Photogrammetry sensors are used to build 3D models of landscapes and buildings. Thermal vision and low light night vision sensors are used by drones to scan landscapes, building to assist in agriculture, search & rescue, firefighting, and so on.

A technology called Sensor Fusion can be used in drones in which drones carry different sensors with software combining the data together for better results. These systems automatically combine input data from several different sensors such as regular RGB camera, thermal camera for the purpose of improving system performance or application. Combining data from multiple sensors reduces and corrects the errors as compared to using individual sensors to calculate the accurate position and orientation information. For e.g. Multi-Spectral sensors in drones can create Digital Elevation Maps (DEMS) of land areas to provide precise data on flowers, shrubs, trees, fauna, and on the health of crops or more.

Drones with Time-of-Flight (ToF) sensors came to the market in 2016. ToF is also called Flash Lidar which can be used on its own or can be combined with RGB and regular LIDAR sensors to provide economical solutions across various sectors. ToF depth ranging camera sensors can be used for 3D photography, tracking objects, measure volumes, object scanning, obstacle avoidance, indoor navigation, gesture recognition, gesture recognition, augmented reality games, and much more. These Flash LIDAR ToF cameras have a huge advantage as it can measure distances to objects within a complete scene in a single shot. In photogrammetry and lidar mapping, the UAV is programmed to fly over an area autonomously, using waypoint navigation [19]. The camera on the drone will take photographs at a continuous interval like every 0.5 or 1 s then these photos will be stitched together using specialized photogrammetry software to create 3D images as shown in Figure 1.8.

DroneDeploy is a widely used 3D mapping software. It’s a mobile app and a live map is being used in various sectors for creating 3D models and maps. Their specific software solution for the agricultural sector and others work with most of the latest drones.

Figure 1.8 Visual representation of a fixed-Wing platform taking photographs at its designated points [39].

Capturing high-resolution images on a drone that is stabilized is important and using top photogrammetry software to process them into real maps and models is just as important. Some of the top drone mapping softwares are as follows:

 • Autodesk ReCap Photogrammetry Software.

 • Pix4D-Mapper Photo-grammetry Soft.

 • Drone-Deploy 3D Mapping Solutions.