400,000 commercial and government drones will fly over European airspace by 2035 at less than 150 meters. How to avoid chaos?
Luis Moreno Lorente, Charles III University
In the last 25 years there has been an enormous advance in the Unmanaged Aerial Vehicles (UAVs), popularly called drones. SESAR, the technological pillar of the Single Digital Sky of the European Union, has given a figure for the future: 400,000 commercial and government drones will fly over European airspace by 2035, but it could be more.
If we calculate, to make an estimate, that there will be a drone every 10 km², in Spain there would be 50,000 more or less. And they will fly, if the legislation does not change, less than 150 meters from the ground.
The sky is going to be filled with unmanned aircraft. Science fiction does not give much room to imagine how things will be, because the future in movies is usually imagined with flying cars, but not with pilotless ships, providing all kinds of services.
without losing sight of them
Unmanned aerial vehicles (UAVs) can be fixed wing or multirotors. They started out as teleoperated vehicles and have become increasingly sophisticated. Today autopilots already exist, which automatically execute the flight path determined by an operator.
The established trajectory is sent through a radio link to the UAV and it executes it, periodically sending its position data to the station. But today, for everything to go smoothly and not lose control, the operator must have the UAV in sight.
This form of control is the most widely used today, but it presents a large number of complications, and it is essential to solve them in view of the increase in the number of vehicles that will populate our airspace.
To begin with, automatic path planning becomes difficult in complex environments, such as cities, areas with difficult terrain, high obstacles, etc. On the other hand, the short range of the communications used implies the loss of control of the UAV beyond a certain distance. There is an additional problem, and that is that an operator is needed for each drone.
There is an added weak point, and that is that each UAV is individually planned, operated and controlled without taking into account the other vehicles that may be in the area.
Fly with more drones nearby
When the number of UAVs increases, control becomes more complicated. If we think that the drone is going to fly in a complex environment, where there may be tall buildings and the operator supervising the UAV cannot maintain visual contact with the vehicle, flight paths must be automatically planned, coordinated with other nearby drones , and control its correct execution to avoid potential conflicts between aerial vehicles that could lead to accidents.
In this context, the European project Labyrinth H2020. It deals with the planning and automatic control of multiple UAVs flying at the same time, guaranteeing the safety of civil transport in ports, highways, airports and for emergency support.
the perfect choreography
In these sandboxes, planning is carried out for each set of UAVs. We determine the flight paths, which not only include the spatial position (longitude, latitude and height above the ground) but also the time in which they must pass through each indicated point.
The planning of these trajectories must avoid obstacles on the ground. It must be taken into account that current legislation limits the maximum height in relation to the ground at which the vehicle can fly, which is less than 150 meters.
This, in the case of non-urban or industrial environments or urban areas of single-family homes, is not a big problem, but in the case of large cities it is a major difficulty, since many buildings exceed 20 floors (65 or 70 meters). high) and in many cases there are skyscrapers that reach heights close to or greater than 150 meters.
3D maps of each flight zone
In complex environments, planners need to use three dimensional maps of the area through which they are going to move. These are obtained from the lidar maps or similar that provide the various Geographic Institutes Of each country.
These maps can be converted into 3D spatial occupancy maps, indicating for a given spatial cell (a cube of given height, width and depth) whether that space can be traversed or not. With this information it is possible to determine safe three-dimensional trajectories, in which the UAVs avoid obstacles.
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Communication with the UAV must be immediate
A second difficulty that arises is the need to keep all UAVs identified and receive information on their status during flight. You have to know its exact position, speed, orientation, and other parameters at all times. This is necessary to determine if the trajectory is being executed correctly without significant deviations from what was planned, both spatially and temporally.
For this, a fast, secure and powerful communications system is required.
Specific radio frequency links are traditionally used, but this, which is reasonable for a single UAV, is not feasible for a high number of UAVs in flight at the same time. The trend is that communications are made using the 5G mobile phone networks. The flight paths, the UAV status information and the environment data that the UAV collects with its sensors are sent through them.
Prevent in-flight hacks
This leads us to the third problem, which is the need to maintain the entire UAV traffic control and management system with a security level that prevents unwanted intrusions into the system, that is, its cybersecurity.
The proper functioning of these systems is beginning to be tested in limited and controlled environments: ports, airports, agricultural and industrial areas. Once it has been shown to work, its use will be extended to other areas, until it reaches the city.
Thus, it is foreseeable that we will gradually begin to see an increase in UAVs operating in our skies. In any case, its incorporation into our daily lives is something that will undoubtedly occur.
Luis Moreno LorenteUniversity Professor in the area of ​​Systems Engineering and Automation, Charles III University
This article was originally published on The Conversation. read the original.