It is very common today to see or hear the term “drones” for one reason or another in the media, on social networks and even in our daily conversations (with more or less success) as an example of technological progress, as platforms for potential future applications and even as protagonists in films or videogames. However, we make use of the word without really knowing what it means and without attending to the more precise terms that exist for them nowadays.
Everyone will understand you when you use the word drone, but if you want to convey a technical, modern and concise message, it is better to use the most appropriate terms, such as RPAS.
It is also possible that on more than one occasion you have heard or used other terms, such as RPAS, RPA, UAS, UAV, ART, VANT or some other similar term.
But, ….which is the correct term? In this article we will try to provide you with more information on the matter.
To do this, three background clarifications should be made:
1. Drones are of military origin. It’s only since their technology has recently been democratised that drones have also had a place in the civil sector. The terms used are therefore usually of military origin.
2. There are differences between the type of control of the majority of civilian or industrial drones and the majority of military or security drones.
Most common civil or industrial drones are tools that have the sole task of collecting data, tirelessly and automatically. This task is programmed beforehand with a clear objective: create an efficient flight pattern in order to carry out the task in the shortest time possible. Anything that implies deviating from that programmed flight plan means wasting time and, therefore, efficiency. The machine is continuously supervised by a human, but the active intervention of a human (i.e., taking the machine out of the automated execution of its program in order to control it manually) during this type of flight is considered detrimental, as it results in a loss of efficiency. It is, therefore, a remotely supervised aircraft with a rigid and perfectly established objective. The flight is programmed and continuously supervised. The operator does not normally need to pilot the aircraft, although some do require this intervention during the take-off and landing phases.
Conversely, drones for military use, and in general drones for all uses related to surveillance/security, are the very opposite of the previous case. The objective of the flight develops during the flight itself, as the expected events arise (or not). For example, the detection of an intruder and subsequent monitoring requires modifying the flight plan to adapt to this new circumstance. Therefore, this type of flight requires a human pilot who not only supervises the flight, but also modifies it manually according to the needs of the mission. It is, therefore, a remotely piloted aircraft with a variable and flexible objective that is configured according to how the mission develops. It is a manually controlled flight and it is continuously supervised and piloted by a human.
Of course, there are cases in which both types of control are combined, but the most usual situation is that most of the flight is of one type or another (programmed or manual control).
3. It is necessary to clearly differentiate between drones that are aerial devices that execute a specific task for a specific mission (commercial, security, support or other tasks in the civil and military sector, or even intelligence in the defence sector) and recreational flying devices that do not really fulfil any function other than the entertainment of their users (aeromodels and toys).
Now that we understand these principles, let’s look at the main terms one by one:
This is the most common and widespread term, but it is also the most general and least technical term that is least liked by professionals in the field.
Drone literally means “male bee”, and there are many people who attribute the name to the possible similarity between the flight of the insect and that of the machine. However, “drone” also means “buzz”, and it is more likely that these machines began to be called “drones” as they are usually only detectable by their persistent “buzzing”.
The term drone encompasses everything that moves through the air with a minimum amount of steering ability, and with no criterion other than not having a pilot on board. It is a term that is used ad naseum in films, and it has therefore been adopted extensively by the general population, who also employ it indiscriminately. If you work in the field, you will probably shy away from using this term, because it is not very technical. Try not to use it, as there are other much more technical expressions, such as those described below.
This expression is often used in reference to multicopters and toys. Users and manufacturers of larger and more complex systems are not very prone to using it.
If possible, do not use the term drone unless you are addressing a general audience who have little knowledge about this kind of technology.
UAV (Unmanned Aerial Vehicle)
UAV stands for Unmanned Aerial Vehicle. The acronym VANT (Vehículo Aéreo No Tripulado) is used in many Latin American countries, but curiously, it is not used in Spain.
The term UAV was one of the first to be used to designate these aircraft. It originated in the military sector, and it is still deeply rooted in that environment.
The term was intended to clearly differentiate between aircraft that had a pilot inside them and those that did not. This is particularly relevant when working in operational scenarios and when transmitting orders in environments that include both UAVs and manned aircraft. In such operational scenarios, UAVs must be well identified so that the pilots working with them know what to expect, both in terms of responses and behaviour.
The term UAV implies that the aircraft is not manned by a human. In fact, it implies that the aircraft may not be manned in any way, and therefore it is especially associated with programmed flight aircraft. In other words, the aircraft is self-steered and self-controlled thanks to a program that is already established and loaded into its memory before the flight (continuously supervised flight).
This programmed and continuously supervised pattern of action is how small aircraft dedicated to civil data collection tasks such as topographical surveys usually fly.
The term UAV is still used a lot, although it is considered a bit outdated and not very descriptive, so it is losing ground in favour of the term RPA, discussed below. It defines industrial and civil aircraft very well, but for regulatory matters these are also included under the term RPAS, as regulations do not currently distinguish between a remotely supervised aircraft and a remotely piloted one.
This term should be used when talking about aircraft with programmed flights. You can also use it colloquially and generically in defence environments (although this is less and less accepted) or with veterans of the aeronautical industry who still use it.
A special derivative of this term is UCAV (Unmanned Combat Aerial Vehicle). This is the same as UAV, but with the particularity that the aircraft is only intended for aerial combat. These aircraft are still under development and, although they have even taken off and landed on aircraft carriers (such as the X-47), their limited ability to make decisions autonomously combined with the difficulty of having a good situational awareness means that they still depend on a human pilot on the ground to fly them. At the same time, as an equally viable technology, but with less need for development, manned fighters (such as the F-16) that have incorporated all electronics and communications required to be remotely piloted are currently being tested.
UAS (Unmanned Aerial System)
This is a refinement of the term UAV that covers all the elements in the system (the term UAV only covers the aircraft), i.e. ground station, sensors, communication antennas, etc.
This term is more appropriate than UAV when referring to the whole system (which is usual) and not strictly to the aircraft.
Use UAS when you are talking about the entire system (aircraft and everything around it) in the same cases as you would use the term UAV. Like UAV, it is a term that is slowly fading away.
RPA (Remotely Piloted Aircraft)
This is the most current definition. The acronym ART (Aeronave Remotamente Tripulada) is used in many Latin American countries, but curiously, not in Spain.
Its origin is largely due to the need to convey the positive idea that there is a human behind the machine, supervising or controlling its actions, in contrast to the term UAV which, in some way, is not clear in that regard.
Use this term when you want to refer technically and accurately to an aircraft that is normally being actively manned/piloted (not just supervised) from a ground control centre.
RPAS (Remotely Piloted Aerial System)
This is the most commonly used and most accepted technical term for all systems containing a continuously piloted and supervised aircraft. A refinement of the term RPA, it is used when referring to the complete system. In other words, it includes not only the aircraft, but also all accompanying subsystems, such as the ground station, communications, etc.
There are experts who believe that RPAS is actually a subclass of UAS, because they consider that all drones share the characteristic of having no crew on the aircraft, and RPAS simply denotes that, in addition to not having a human on board, it is actively piloted from a distance. However, strictly speaking, no drone is without a crew, as the crew is either controlling its action from a distance or supervising the mission.
Use this term when you are in a technical and professional environment. You can use it for all aircraft systems, whether they be continuously supervised or continuously piloted, even though the most appropriate use would be only for continuously piloted aircraft and not for continuously supervised aircraft… But before we can reach that point, we have to wait to get new and updated terms and definitions. In the meantime, we have to work with those that already exist.
To sum everything up:
Use whichever term you find more suitable, as there are no limitations in that regard (not even on a legal level). Everyone will understand you when you use the word drone, and the important thing is that you make yourself understood by your audience. But if you want to convey a technical, modern and concise message, it is better to use the most appropriate terms, such as RPAS.