The accessibility and affordability of drones have resulted in many surveyors and mapmakers to adapt them as tools. Not only do they significantly shorten the length of operations, they also save money on work hours.
Undertaking a successful drone surveying operation requires the surveyor to not only understand the tools available, but also to select the right ones since there are several different UAV/drones and payloads, drone autopilot software, and image processing software.
Planning A UAV Surveying Mission
Even before you get started, you need to ensure mission planning is successful. You will need several different software when doing mission planning. The aims of mission planning is to ensure –
- The mapping work follows all Federal Aviation Administration or European Aviation Safety Agency, or Civil Aviation Safety Authority rules and regulation, and does not enter any air space boundaries,
- The flight of the drone is done at an opportune time. This includes when there is a relatively clear sky, and when the place is most free of people.
- All the things needed for a successful drone surveying operation has been adequately taken care of such as the battery in the drone, and autopilot directives such as altitude and flight overlap.
Choosing the Right Autopilot Application
Choosing the right drone autopilot software is essential since it will be doing most of the work, such as flying uniformly over the field to be surveyed and taking the pictures. All the surveyor needs to do is to set the coordinates for the area to be mapped, image overlap and the altitude of the drone.
Some factors to consider when choosing an autopilot software include
- The method by which the software triggers the camera. Is it through the drone itself, through the camera or through the controller?
- Does the software makes the drone to take photos even when turning, or does it take photos only when flying straight?
The UAV and Components
If you are new to UAV, surveying it is best to start small, and then advance from there. Instead of starting with highly specialized add-ons and tools, why don’t you start with a proven survey drone that is inexpensive?
Fixed-Wing or Multi-Rotor
One of the first things you have to decide when getting a drone is whether the drone has a fixed-wing or us multi-rotor.
A fix-wing drone looks like a glider. The advantage of fix-wing drone’s shape and wings enables it to fly over a much larger distance on the same amount of power as a multi-rotor drone. While a fixed wing drone can fly for hours since they are efficient at managing power once they are airborne, a multirotor drone can fly for minutes. The downside to fix-wing drones is their price. As such, it is best to get started with multi-rotor drones since regulations dictate that the drone is in the line of sight of a human controller at all time. This line of sight rule negates the long flight endurance advantage of fixed-wing drones.
There are several types of sensors available to drone cameras such as LiDAR (Light Detection and Ranging) radar and Multispectral imaging camera sensors. Unless the job requires you use a certain type of image sensor, stick with a standard camera since other fancy sensors are expensive and provide just marginal advantages.
When getting a camera get one that is capable of taking high-resolution images. A drone that vibrates the camera may result in blurry images. Devices such as gimbals and vibration isolators ensure the camera is stable. In addition, fast lens and quicker shutter speed result in sharper images.
Drone Mapping Data Processing
There are many drone mapping software available. The job of the software is to process the raw data by combining separate images taken into one ortho-photomap or three-dimensional model and to georeference the map using GPS data gathered by the drone. In addition to GPS data gathered by the drone, ground control points allow to better accuracy.