What does the future hold for drones in security and defence?

As drones and UAVs continue to permeate ever more sectors of society, Innovation News Network speaks to Dr Stephen Prior, from the University of Southampton, about the potential applications of drones in security and defence.

As the role of unmanned aerial vehicles (UAVs) continues to grow in all sectors of society, new applications for drones in security and defence continue to emerge. While the possibilities presented by drones in the theatre of war have already been explored, more research is now being undertaken into their potential for improving security.

The European Commission has already recognised the potential of drones in security and defence, and is working together with the European Aviation Safety Agency (EASA) to help build more information and grow the understanding of how these powerful devices could prove useful for meeting security challenges in the future.

Innovation News Network spoke to Dr Stephen Prior, reader in Unmanned Air Vehicles within the Faculty of Engineering and the Environment at the University of Southampton, to find out what the future holds for drones in security and defence.

How are drones being used in the defence and security sector in Europe? What advantages do they bring over other technologies?

It is still fairly early days for drones at the moment and therefore the use of them in security is fairly limited at this point in time. There are a lot of recent projects which are testing the water, but there is no major infrastructural protection. There is a lot of interest, but it is converting that interest into a commercial product and/or service which is a challenge, and this is where we are at. I think it will come, though.

How long do you think it is going to take for it to take off?

I believe that in the next five to ten years we will see a major change in this approach. When it comes to talking to investors and companies, there is a reluctance centred around questions such as cost and whether drones in security and defence are really needed. Unfortunately, until something happens, people generally don’t see the benefits of having sky defence, as we are always fixated with ground defence such as security gates, guards, and watchmen.

The third dimension is the future in terms of breaching security. People climbing over fences or walking through gates with fake passes is still a threat, but it is not going to be the only threat and I think people have lost perspective about the third dimension. You can fly over any size fence very easily, and you have no defence against such an attack. Petrochemical plants, nuclear plants, big infrastructural buildings and government buildings are pretty much wide open at this point in time, and just because no one has attacked them yet, it doesn’t mean someone isn’t going to try in the near future. Unfortunately, I believe that it will take an attack to focus people’s attention and see the benefit of a third dimension defence.

One of the challenges for security drones is their battery life, which lasts around 25 minutes on average. Is this an impediment to their use in security?

There are two things to focus on here. Firstly, you can fly quite a long way in 25 minutes; 99% of drones are battery powered, but they can still fly five or ten kilometres in that time. This is a long way to defend your territory. We are looking at all of the different types of battery technology and the ones that are coming through now are new things such as solar energy, hydrogen fuel cells (HFC), lithium-sulfur (Li-S), and even things like nuclear batteries. The target is to power a drone so that it can fly for around an hour and carry 5kg of payload – this is the current marker which we have been set, and we believe that this is achievable with a HFC system.

Other people are looking at hybrid systems; fuel engine/battery hybrids are key here when it comes down to the specific energy of the battery source or fuel source. In terms of numbers, lithium polymer has about 200 Watt-hour per kilogram (Wh/kg). Hydrogen fuel cells are about two or three times more than this, and then fuel/battery hybrids are a little bit more than that (900 Wh/kg). There is not much difference between all of these solutions, however, and each one has advantages and disadvantages. For example, the problems with fuel engines include being noisy and heavy; they have a heat signature, they pollute, they have a lot of vibration, and having a fuel source can be dangerous.

Hydrogen fuel cells are also heavy and they require certain things which are more difficult to attain, such as pressurised hydrogen. This is why we come back to the simple solution of a battery system which is rechargeable, universally available and very low cost.

Li-S batteries developed by Oxis Energy Ltd in the UK are just about to emerge from the production line and into service. It is believed that these could potentially double flight time instantly (400 Wh/kg). The trouble with multi-rotor aircraft is that they require a lot of current (40-60 A) to draw from the battery source. The source has to be able to provide the battery power, which is something which the newer technologies are not very good at (they have a low ‘C’ rating).

It is an open market and there are a lot of innovations emerging with each of them claiming to do one thing or another. However, in reality they don’t meet the commercial metric of their own advertising or marketing. I am sure they will develop over time, but battery technology tends to move relatively slowly. Each generation comes along every five years or so, making it a slow, incremental progress.

Are there other challenges to the wider implementation of drones in security and defence?

Yes, there are many. Number one is permission to fly. If you are a responsible operator, you need Civil Aviation Authority (CAA) permission. The CAA in the UK grants permission to fly commercial operations. Currently, they won’t allow you to fly the drone more than 500m from the pilot in command of the UAV. This is a real handicap in terms of doing anything useful at range. Drones in security and defence might need to fly non-line-of-sight, or above and beyond visual line of sight.

In the USA, they follow a registration system and a drone pilot licence is required; however, permissions are governed by drone mass. Under the new rules, if a drone is below 250g then there are no required permissions for flying under the new European regulations structure. There is also a new 80 Joules of kinetic energy of impact with a person condition (<900 g). Once you get to 4kg (or 7kg in the UK), further permissions start to be introduced, which continue to get stricter once a drone is <25kg (20kg in the UK), then stricter again at 150kg.
In the light of Brexit, there is uncertainty over whether the UK will follow the European model or whether there will be an individual, UK-based model. It would be beneficial to have one universal set of rules, however, because if a drone flies from the UK to France, without a universal structure, permissions from both countries would have to apply to the one drone.

There are examples where drones and UAVs have been used in terror attacks. What can be done to tackle this? Is it a case of restricting access to drones?

I don’t think this can be easily tackled. Criminals are known to build their own drones and there is no way you can stop this. Banning the sale of them in supermarkets and shops will not have an impact. DJI (with 70% of the market share) sold over one million drones last year in America alone.

Various suggestions have been put forwards in the field of drone detection and prevention. In Holland and France, there are eagles which can fly out and capture drones. However, when a UAV is over a certain size or mass, the hawk can no longer do this without risk of hurting itself or destroying the drone in the process. There is also the worry that if the drone is carrying a bomb, and this falls from the sky, it could create a major issue.

In Japan, they have innovated a net system, where the UAV fires a net at the drone and captures it. This has been proven to work. At the G7 event they had a large drone gun (DroneDefender) which is essentially a powerful RF transmitter; it is an RF device which bombards the drone with so much energy that it overwhelms the drone control system and can then guide it down. However, you can only stop a drone if you can see it; you can only stop it if you know where it is and depending on how fast it is. It can be a very difficult target to safely take out.

Racing drones, for example, are about 300mm in diameter and travel around at over 60mph – you would not see or hear a drone like this. It would even be difficult to identify it against the background when flying at a low level.

Many people have suggested shooting down a drone with a shotgun. However, if the drone is carrying something dangerous, for example Anthrax, having this dispersed above your head in a crowd situation is not a good idea.

I think we need a system in place, and there are definitely solutions out there (such as Drone Control UK) to the challenges of drones in security and defence. However, there are no solutions which cover everything. Radar solutions can be very costly and they cannot distinguish between a small bird or a small drone. TThere are a lot of birds flying around and it would not take a genius to design a drone which takes the appearance of a bird. Drones don’t like gusts of wind, and so, as another example, we have thought about a cannon which exhales blasts of air. There are a lot of potential solutions, some of them are very expensive and some of them are very exotic; we are still learning about what needs to be done.

What threats do these drones pose to European citizens if such attacks are not defended?

Anything which you can strap to a drone is potentially a threat to anyone who is on the ground. It doesn’t have to be an offensive weapon; you could attach flour to a drone, the stampede which could be created from that (as people would fear it was a dangerous powder) could potentially injure a lot of people without intentionally being dangerous to anybody. It is more of the threat than the actual reality of the threat which needs to be considered.

What are the next stages that need to be taken to increase the applications and uptake of drones in security and defence?

I am a non-executive director of Tethered Drone Systems Ltd and we have created a tethered drone system, which is our solution to the batteries (endurance) issue that we have discussed. Here, you would attach the UAV to the tether and then power it up from the ground and downlink communications on a fibre optic cable embedded in the tether. This enables you to go up to 100-300m above ground level and look around from an aerial point of view. It also allows you to drive to another location and deploy it somewhere else at ease, making it a very viable solution for drones in security and defence in particular.

Other people are building drone systems for patrolling; they are building multiple drones which can fly out in formation. Sending drones in all different directions, to do different things would be a powerful tool to either attack or defend, depending on the purpose.

Drones in security and defence will become more sophisticated and more intelligent, and they will become more capable. They will be able to withstand adverse weather conditions during flight; they will be able to carry more payload; they will be able to fly faster; and they will be able to fly further. Technology is moving very fast; all of the developments in drone technology have happened in the past 10 years. Since the price of electronics has fallen, intelligence has increased, and people have started using drones. If anything, they are just going to get smarter and they will fly autonomously; eventually, we may not even require a pilot any longer.

The ultimate goal in terms of our own research for drones in security and defence is to create a UAV which can carry people. It could be used to perhaps fly soldiers the last mile into combat or take an injured soldier out of combat and back to base. Or it could be used to resupply troops or make the last mile delivery of goods. It could even be used to fly people to work in the morning, meaning they wouldn’t have to experience traffic jams or delays.

It is an interesting time to be involved in the sector.

Dr Stephen Prior
Reader in Unmanned Air Vehicles
Department of Aeronautics, Astronautics and Engineering Faculty of Engineering and Environment
University of Southampton

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