PRE2020 3 Group1

Team Members

Name	Student number	Department
Tristan Deenen	1445782	Computer Science
Jos Garstman	145722	Mechanical Engineering
Oana Radu	1325973	Computer Science
Ruben Stoffijn	1326910	Biomedical Engineering
Daniël van Roozendaal	1467611	Medical Science & Technology

Planning

Week 4:

• Start on research model (Oana and Tristan)
• Forest fire and detection (Daniel)
• Introduction (Ruben)
• Physical requirements of the drone(Jos)
• Adding interview and planning(Jos)

Week 5:

• Continue on model
• Finish research week 4
• User requirements (Ruben)

Week 6:

• Continue on model
• Legal suggestions and exemptions/privacy (Licence)

Week 7:

• Finish up model
• Final conclusion/protocol
• Final presentation

Week 8:

• Finishing up Wiki page

Introduction

With dry summers becoming more and more frequent in the Netherlands, the risk of wildfires is becoming substantial. Last summer, the biggest ever national wildfire destroyed 800 hectare of Deurnese Peel. Eventually, the fire department got the fire under control. The Dutch fire brigade is currently experimenting with drones to fight fires. With a number of drone teams already operational, the fire department is making big strides in innovation. Currently, drones are used to support teams while fighting fires or evacuating buildings. The fire department has indicated that flying drones for fire prevention would save the most resources. They are not currently doing this, mainly because of a responsibility gap involving staatsbosbeheer and the fire department.[citation needed -> interview] Since looking after national parks is the responsibility of staatsbosbeheer and the fire department are experimenting with drones, we propose a plan for cooperation. Where drones can be deployed to survey national parks during extreme drought and fire hazard. We will go over ways to automatically detect starting fires. A simulation will be performed to estimate drone response time and coverage. The drone specifications and hardware limitations will be explored. The level of feedback and control that the user will have is suggested. The legal and ethical questions regarding semi-automatic drone flight above nature reserves are addressed. All these points of attention come together to form a propositional protocol, that staatsbosbeheer can realistically use during extreme weather, given sufficient funding.

Forest fires and detection

It is believed that over 95% of all wildfires are not caused naturally but caused by humans, intentional and by accident. The main reasons found in a research in Santa Monica and San Diego are arson, power lines and sparks by cars or equipment. The area burned by a fire that was caused by arson was found to be the largest.

https://www.publish.csiro.au/wf/wf14024

Lightning strikes the Earth over 100,000 times a day. Of these, 10-20% cause a fire. https://nhmu.utah.edu/sites/default/files/attachments/Wildfire%20FAQs.pdf

The speed of a wildfire spreading can be up to 14 miles per hour (23 km/h).

https://science.howstuffworks.com/nature/natural-disasters/wildfire.htm#:~:text=Everything%20has%20a%20temperature%20at,air%2C%20combust%20and%20create%20fire. 

There is a difference between forests and grasslands fires. Wildfires in forests spread slower with speeds up to 6 miles per hour (10 km/h). In grasslands speeds up to 14 miles per hour can be reached. https://www.forbes.com/sites/startswithabang/2017/09/06/the-terrifying-physics-of-how-wildfires-spread-so-fast/?sh=5bc097d97791

There is a rule of thumb saying that wildfires have an onward rate of fire of roughly 10% of the speed of the wind. https://link.springer.com/content/pdf/10.1007/s13595-019-0829-8.pdf The average windspeed in the Loonse en Drunense Duinen over the year is around 4.0-4.5 meters per second (14-16 km/h). 10% of this is around 1.5 km/h so the wind would have a very small influence on the speed. Given the rule of thumb has not been proven to apply to grasslands and the Loonse and Drunense Duinen is a combination of forests, grasslands and sandbanks we will disregard the influence of the wind. https://www.knmi.nl/klimaat-viewer/kaarten/wind/gemiddelde-windsnelheid/jaar/Periode_1981-2010

The temperature when a material will burst into flames (also called the flash point) of wood is 572 degrees Fahrenheit (300 degrees Celsius). https://science.howstuffworks.com/nature/natural-disasters/wildfire.htm#:~:text=Everything%20has%20a%20temperature%20at,air%2C%20combust%20and%20create%20fire. Given the difference between this temperature and the average maximum surrounding temperature in the Loonse and Drunense Duinen being 23.5-24.0 degrees Celsius, any fire will easily be detected by an infrared sensor. Even in extreme temperatures of 30 degrees Celsius or higher, the difference with flaming wood will be around 270 degrees Celsius. This difference being so high means that even small, starting fires can be detected. https://www.knmi.nl/klimaat-viewer/kaarten/temperatuur/maximum-temperatuur/juli/Periode_1991-2020

Forest fire detection is typically performed by some combination of watchtowers, aerial detection patrols and satellite imagery. Watchtowers have to be carefully placed to be have enough visibility to be useful, they are often expensive to build and it is not very flexible as the view is permanently decided once a watchtower stands. Satellite images play an important role if fire management and strategic fire intelligence as it covers a lot of territory and can detect medium to large fires using (semi) automated algorithms. Some exceptional satellites can even be used to detect small fires but overall satellite visits are often too infrequent and the image resolution makes detection of smell, developing fires difficult. The time lag of a user receiving data from satellites can take hours and weather can limit availability of satellite data, making it inconsistent and unusable for fire detection.

Compared to fixed-wing airplanes, helicopter provide much more manoeuvrability, they can hover and they can land or take-off in more varying environments. On the downside helicopters a typically more complex, more expensive and have less range and payload capacity than fixed-wing aircrafts of a similar size. UAVs provide the most safety for humans involved by removing them from the field, which also reduces cost and weight.

Heat detection is an obvious method of detecting fires in natural areas. Normal temperatures are on the thermal infrared (TIR) region. Higher temperatures like that of typical fires, are on the mid-wave infrared (MWIR) of shorter wavelengths. Many sensors detect near infrared (NIR) and shortwave infrared (SWIR) and can be used for detecting fires. Large clouds of smoke, caused by forest fires, can be detected on standard cameras when there is enough light but these still have to be identified by humans. In the dark, fires can also be detected using night vision goggles (NVG).

more info here, very useful source… https://www.mdpi.com/1424-8220/16/8/1310

If we divide the response time up in periods of 10 minutes, we can calculate how much effect each 10 minute periods have on the size of a wildfire. For this calculation, we are going to approximate a fire as an expanding circle. Every time 10 minutes pass, the amount the fire grows is bigger because the same increase in diameter of a circle is bigger if the original circle already was bigger. If we use the speed of fire spreading being 14 mph, we will get around 23 km/h which gives us around 4 km for every 10 minutes. The first time period starts as ignition and after this period we have a circle with radius 4. The radius increases with the same amount every time period. The results are shown in the table below.

Time period	Radius (km)	Area (km^2)	Area difference (km^2)
1	4	50	50
2	8	201	151
3	12	452	251
4	16	804	352
5	20	1257	453
6	24	1810	553
7	28	2463	653
8	32	3217	754
9	36	4072	855
10	40	5027	955

Type of drones

Currently there are around four main types of drones. Namely single-rotor, multi-rotor, fixed-wing and fixed-wing hybrid drones. All these types have different their own strengths and weaknesses and depending on the usage one might prefer one over the other. In this section a run-down of these four main types will be given, mentioning both their pros and cons.

Multi-rotor drones
Multi-rotor drones are surely the most popular drones on the market. They are good starter drones because they are cheap and easy to use. They have multiple rotors keeping them up, can take-off vertically and have great control in the sky with the option to hover in place, this way the surrounding area can be observed for a longer time.

There are, however, also quite some downsides to this type of drone. A multi-rotor drone is constantly fighting gravity to stay up in the air. This requires a large amount of energy and is generally not very efficient. A multi-rotor drone with a light payload can only stay in the air for around 20 to 30 minutes. On top of this the design of this type of drone also limits their speed. Currently they are also restricted to the use of electric motors.

All in all a multi-rotor drone is a cheap way to get an aerial view of the nearby area for a short amount of time, but they are not suited for long duration flights over long distances

Single-rotor drones
Single-rotor drones are of course quite popular in manned aviation, but are not that widely available in the drone world. It has a single rotor with a tail rotor to control direction. A single-rotor drone is much more efficient than a multi-rotor drone because it has one much larger rotor instead of several smaller ones. Next to this they can also be powered by a gas motor for even longer flight times. Also they can carry much heavier payloads than multi-rotor drones.

The downsides of single-rotor drones are that they are much more complex and harder to handle. The cost and maintenance are also quite high because of the mechanical complexity of the copter. Finally the longer, sharper blades of the single-rotor are much more dangerous and can deal some serious damage.

Fixed-wing drones
The main difference between rotor-drones and fixed-wing drones is that a fixed-wing drone uses wings to generate lift instead of rotors. This way a drone only needs to create forward momentum and takes advantage of physics to stay up in the air and increase efficiency and speed. because of this big increase in efficiency and speed fixed-wing drones can stay in the air for longer and thus cover much larger distances than rotor drones. Additionally a gas engine can be used as power source for even better endurance. This way some fixed-wing drones can stay in the air for more than 16 hours.

The main disadvantage of fixed-wing drones is that they cannot hover on the spot and are always moving forward. It is much more difficult to survey one area and take a closer look if more info is needed. Also take-off and landing is more difficult because of the high speeds. Depending on their size a runway or catapult are needed to launch them into the air and either a runway, parachute or net are needed to retrieve them again. Some smaller drones are capable to be launched by hand and land safely on their belly in a field. Some other cons are their higher costs and difficulty to control.

Fixed-wing hybrid drone
A fixed-wing hybrid drone combines the main advantages of rotor and fixed-wing drones. These types of drones are also called VTOL's, which stands for Vertical Take-Off and Landing. These types of drone do not need a runway or catapult to take-off but can tilt their rotors or switch between rotors to take-off and land vertically, but fly like a fixed-wing drone. Currently there are not many hybrid drones on the market but several companies such as amazon are doing research into this type of drone for delivery purposes.

The combination of the two types of drones means it is not perfect in either hovering or forward flight, but the option to hover greatly increases its functionality.

Summary

Pros and cons of different types of drones

Drone type	Pros	Cons
Multi-rotor
Single-rotor
Fixed-wing
Fixed-wing hybrid (VTOL)

• https://www.auav.com.au/articles/drone-types/
• file:///X:/Downloads/COMPARISON_OF_A_FIXED-WING_AND_MULTI-ROTOR_UAV_FOR.pdf

Drone Functionalities

For the drones to be able to successfully survey an area and detect hotspots they will need to have certain qualities. In this chapter a list of functionalities will be given and explained in further detail. Several options will be laid side to side and recommendations for the drone will be given. The following functionalities are needed for the drone:

1. Detection of temperature difference to spot beginning fires
2. Detection of surrounding environment for additional information
3. Path-finding and collision detection
4. Large range to patrol surrounding area
5. Communication of data with main operating base/main operator
6. High visibility for surrounding environment
7. Low noise for surrounding environment
8. Optional: means to delay and/or extinguish beginning fire

Sources (To be referenced)

• Allison, R. S., J. M. Johnston, G. Craig, and S. Jennings. 2016. “Airborne Optical and Thermal Remote Sensing for Wildfire Detection and Monitoring.” Sensors 16 (8): 1310–1339. doi:10.3390/s16081310.
• Colomina, I.; Molina, P. Unmanned aerial systems for photogrammetry and remote sensing: A review. ISPRS J. Photogramm. Remote Sens. 2014, 92, 79–97.

Detection of temperature difference to spot beginning fires

To prevent a full scale wildfire from occurring, hotspots have to be detected as fast as possible. The detection of hotspots can be done by measuring the temperature of the environment since a beginning fire will have a higher temperature than its surroundings. This temperature difference can be measured in a multitude of ways and sensors, but not all are fit to be attached to a drone. For a sensor to be effective on a drone it needs to be long range, accurate

Thermal camera

To prevent a wildfire from occurring, hotspots have to be detected as fast as possible. The detection of hotspots can be done via thermal cameras. By patrolling and scanning the area, thermal images can be created and compared to detect hotter areas in the landscape. Closer inspection can be done to confirm if a starting fire is present. There are some key aspects to think about when deciding which thermal camera is a good candidate.

First of all its weight. A bigger, heavier camera needs a bigger drone to carry it. At the same time a heavier payload will cause for a shorter air time of the drone and thus the need for a bigger battery pack. When deciding upon which camera to choose, a lighter camera would be optimal.

Secondly radiometric vs non-radiometric. A non-radiometric thermal camera only display a thermal image while a radiometric camera also provides the temperature measurements. For the purpose of finding hotspots and fire-prone areas a radiometric camera greatly improves performance. These cameras can give a warning whenever a certain threshold temperature is crossed, at which point the drone could act immediately.

Next is a stable camera or one attached to a gimbal. When a camera is attached to a gimbal it gives the drone or operator more control over the cameras movement. A gimbal makes it easier to survey the area without having to turn the entire drone

Furthermore the range and thermal sensitivity of the camera. The range means the entire span of temperatures the camera can measure. For the purpose of finding fire-prone areas a lower range is sufficient. The thermal sensitivity of the camera describes the smallest temperature difference you can see with the camera. This means that the lower the number the better the thermal sensitivity is and the better it can detect temperature differences. For this case a low sensitivity is not necessary, since there will generally be wide temperature differences.

IR resolution is also important when choosing a camera. A higher resolution means that the image created contains more detail and information. Especially for longer distances, like a drone surveying the area, a higher resolution is necessary to measure everything in enough detail.+

Finally the spectral range of the camera. This is the range of wavelengths that the camera detects, measured in micrometers. Almost all thermal cameras are longwave cameras which have a spectral range of 8 to 14 micrometers and are appropriate for finding fires.

naturally, all these aspects have an impact on the price of the camera. The wide range of possibilities also gives a wide price range from 1600 to 7000 euros. Dependent on the budget of the user a well-considered choice should be made.

A suggestion for a thermal camera would be the FLIR Vue pro...

^{[citation needed]}

• Colomina, I.; Molina, P. Unmanned aerial systems for photogrammetry and remote sensing: A review. ISPRS J. Photogramm. Remote Sens. 2014, 92, 79–97.
  • Paper about current state-of-the-art UAS and remote sensing. Talks about several sensors used for different spectrums, including thermal imaging. Also mentions different types of drones used for different aspects.
  • Also talks about Autopilot and navigation systems

• https://uavcoach.com/thermal-camera-drone/#:~:text=What%20Can%20Drone%20Operators%20do,a%20particular%20object%20or%20scene.
• https://www.flir.com/discover/professional-tools/thermal-camera-specs-you-should-know-before-buying/

Camera lens

Another important part of the thermal camera is the type of lens. The lens has an impact on the resolution and field-of-view of the camera. The type of lens that is used depends heavily on the situation it will be used in. In the case of a fire-seeking drone, the camera will be at a reasonably high altitude and will need to scout as much area in as little time as possible for maximum efficiency.

First of all the height of the drone. Since the distance to the ground, the target, will be relatively large the thermal images might not that have that much detail. To increase this detail the thermal camera will need a higher resolution. A higher resolution means that there will be more pixels in the image, therefore the area that one pixel represents becomes smaller and thus more detail in the image.

Next the field-of-view of the camera(FoV). FoV means the amount of degrees the camera can observe. A bigger FoV therefore means that the camera can observe more at once, however smaller objects at a larger distance will be more difficult to spot. For the UAV to be able to patrol the largest area a wide FoV is optimal.

When deciding upon which type of camera and lens to use a balance between the amount of detail and the FoV has to be found. For the finding of hotspots the amount of detail is relevant, but the image does not have to be extremely detailed. Once a general hotspot has been detected the drone can be used to investigate further in that area. Still the highest possible resolution is recommended for maximum detail possible. A standard FoV of 45 degrees is recommended to be able to scan a wide area while still keeping high detail.

GPS and localization

For autonomous patrolling of a certain area, sufficient GPS and navigation systems have to be in place. These systems should be able to follow specific flight paths with are predetermined or autonomous flight paths could be implemented based on previous data of hotspots.

• https://www.sciencedirect.com/science/article/pii/S0924271614000501#s0040\

Range

To be able to monitor an entire nature reserve or forest, a big enough range to cover the area is needed. Most drones have enough flight time and speed to reach long distances, however transmission and communication between base and the drone becomes a problem. Currently the Maveric Air 2 drone from DJI has the longest range(for a consumer drone) of 10 kilometres.

Range does not only depend on how big the area is you need to cover, but also from where you are controlling the drone. If the main base is in the middle of the area, the radius does not have to be as large as when the main base is on the outskirts of the area. When surveying a nature reserve however, a drone station in the middle of could not be a possibility for multiple reasons.

Communication

Once a hotspot or starting fire has been detected, this information has to be relayed to the main operating base or fire brigade. This communication should be fast and over a large range.

Battery life

To sufficiently patrol a certain area, a UAV has to have a sufficiently long flight time and thus a sufficiently long battery life. Either multiple drones have to work in shifts to have continuous surveillance or the battery capacity should be large enough so the UAV can patrol during high risk times and charge during low risk times. Battery life is dependent on multiple factors such as drone weight, wind, altitude, propellers and camera use.

Factors such as wind are of course uncontrollable, but to other factors extra attention should be paid, such as weight. The weight of the drone should be kept as low as possible to increase flight time. A lighter drone means the propellers need to create less lift to stay up and the drone can generate more speed. Camera use is also an important factor for the case of hotspot detection, since it will require continuous camera use. This will take a toll on the battery life.

Currently drones will have a flight time of around 20 to 30 minutes. After this time limit the drone will have to return to recharge or change its battery. During this time there will be a gap in the surveillance of the area. To get continuous or near continuous monitoring multiple drones or pre-charged battery packs should be available. The moment a drone returns to recharge another drone can leave to take over its job. Another possibility would be for the drone to quickly switch battery packs so it can continue on its way. A system should be in place however that manages the switching of battery packs.

Collision detection

Collision detection should be part of the UAV's sensors to avoid collision with wildlife, other aerial vehicles or other objects. Most consumer drones have integrated collision detection, however most only in front of the drone. There are only a few drones that have collision detection in all six directions.

Extinguishing/delaying fire

The main purpose of the surveillance drone is to monitor the area and find hotspots or starting fires. As discussed before the flight time needs to be as long as possible to have the most continuous surveillance. To preserve battery life the drone has to stay as light as possible. Therefore the addition of a system to delay or extinguish fires is not a beneficial addition to the drone. A quick response drone could be designed to respond on the signal of the surveillance drone to start extinguishing the fire, but for this case such a system is not worked out and discussed.

Visibility

The UAV should have high visibility so wildlife or other aerial vehicles can see it coming This can be done by means of lights and reflective strips. Also bright eye-catching colours can be used for the drone to stand out from the environment. To preserve battery life the use of lighting should be kept to a minimum and preference is laid upon bright colours and reflective materials.

Noise

Noise should be kept to a minimum if the UAV is flying in nature, both for surrounding wildlife but also hikers or other civilians. Current consumer drones generally create noise between 70 and 80 decibels. This equal to quite loud traffic and excessive noise levels start generally at around 85 dB.^{[citation needed]} Of course the level of noise depends on distance and the dB level will drop over distance. The rule-of-thumb for the drop-off distance is that sound decreases by 6 dB every time the distance doubles.

^{[citation needed]}

Now how a quiet a drone has to be depends on the ambient noise levels which differ per area and time of day. Generally during day time in a busy city centre the ambient noise level will be much higher than at night in a rural forest. Since the surveillance drone will be flying in nature reserves the noise it generates should be quite low. The ambient noise level in a rural area generally do not drop below 45 dBA at day and 35 dBA at night. The ideal noise range for a drone would therefore be 35-45 dBA.^{[citation needed]}

To reach this level the drone could of course fly very high, but this would decrease the detail of the thermal camera and would make it difficult to detect hotspots. Therefore the drone has to be designed in such a way that the noise level is reduced. Reduction of propeller noise can be achieved by increasing the diameter of the propeller while also reducing the rotational speed. This means the blade tip speed is reduced while maintaining enough thrust.^{[citation needed]}

• https://www.airbornedrones.co/drone-noise-levels/

User requirements

Stakeholders

Scouting for fires preemptively benefits multiple stakeholders, and their responsibilities are intertwined. Staatsbosbeheer’s primary task is maintaining nature parks across the Netherlands, so they are responsible for monitoring their reserves closely for fires. The people that hold this task are the foresters. The Dutch fire department is responsible for extinguishing fires. During an interview they have stated that the largest strides can be made in fire prevention. Since wildfires require great resources, preventing them will be beneficiary.

Users

In the early stages of transitioning to drone monitoring for nature reserves, the users will most likely be certified drone pilots. Teams of which the fire department already deploy nationwide. This is necessary because of strict European drone regulations. When, in the course of a few years, reliable autonomous drones can be deployed, the user requirements will most likely become less strict. Allowing foresters to use the system themselves. Because of this predicted shift in userbase, user requirements will change and evolve over time.

Degrees of user requirements

Because drone technology and legal restrictions change over time, drone usage is dived into multiple stages. Note that these stages are not strictly exclusive and overlapping is possible.

Total control

This stage is an example of how drones work in the field currently, for example at the fire department. Current drone regulations require certified pilots. They are this stage's users. Combatting fires usually requires a team of two or three professionals. One for piloting the drone, another for camera controls. The last optional member handles technical problems and helps with the drone setup. Since our goal is surveillance instead of reconnaissance, this solution requires the full attention of at least two pilots, for the largest part of a day. It goes without saying that this is very strenuous and monotonous work. Furthermore, it is not clear if the money is available to pay three full time employees.

The feedback these pilots will recieve is very rudimentory. The drone controlling pilot gets access to images obtained from a front facing camera. This helps pilot the drone from beyond visual line of sight, as well as noticing smoke from far away. The second pilot has control of a thermal camera. They can rotate it and angle it up and down. They arguably have the hardest task, which requires constant evaluation of thermal images for dangerous temperatures. Both video signals are usually fed back to the controllers, but feedback to a computer system is also possible.

Semi-autonomous

This stage, semi-automous, aims to scale the drone team down to only one pilot. This is achieved by automating some simple procedures.

Drones that move automatically already exist, but are not used in any professional fire combatting applications. Since our goal is surveilance, drone movement is not complex and requires only large-scale routing. What we propose is that the pilot brings the drone to a height that oversees the entire nature reserve. Now, the pilot can activate automatic routing mode. This entails that the drone stays at a fixed height and flies directly to specific coordinates. These coordinates, or waypoints, can be manually selected by the pilot. This requires licensed sofware or custom software specifically made for this purpose.

The workload of the pilot will consist of the following tasks:

• Patrol route selection
• Manual drone takeoff
• Thermal camera control and image surveillance
• Manual drone landing
• Battery pack replacement

Feedback will be provided in two major ways: live camera feed from both cameras and real time GPS drone location on a map of the area.

Advanced semi-autonomous

This stage, as the name implies, is an advancement on the last. It cuts eliminates more workload on the surveillance functionality. Since the camera motion is simple and easily programmable, it can be automated with an efficient search strategy in mind. It can sweep around by itself and scan a large area without the need for manual control.

The next step in automating the surveillance task is automatic fire detection, which is explained in detail in link to other heading. The main idea is that the drone supervisor is alarmed when dangerous temperatures are detected. These cameras exist already commercially, mainly for use in factories and other work environments with possible failure due to high temperatures.

With current regulations, the person supervising the drone still needs to be a licensed pilot. Their only task requiring drone piloting is take off, landing, and taking over manual control when routing goes wrong. This greatly reduces the workload on the pilot's part.

Fully autonomous

A fully autonomous system would reduce the responsibility of the user to the bare minimum. The fullest extent of autonomy regarding drone surveillance reaches to complete unsupervised take off and landing and guaranteed safeguards for GPS malfunction. Because the supervisor would not need to intervene, they do not need to be licensed pilot. This does, however mean nobody is responsible for the drone's behaviour. For this to be possible, a change of law needs to take place regarding autonomy and responsibility. Which is only a matter of time, considering the advances in automated cars.

European drone regulations

Since December 31 2020, the Netherlands follow European drone regulations. These new regulations divide drones in 3 separate categories: Open/zero, specific and certified. Normal consumer or hobby drones usually fall in the open category. These drones have a few restrictions:

• Maximum weight: 25 kg (at takeoff)
• Maximum height: 120 meters
• No transporting hazardous material
• No dropping materials
• Always have visual line of sight

There are subclasses for the first category, depending on the weight of the drone. Most relevant is subcategory A3 which concerns drones from 2kg – 25kg. With normal regulations this category cannot fly 150 meters near any living, trade, industry or recreational zones.

The next category, specific concerns flights that:

• May be near people
• May fly near airports
• May have a weight above 25kg
• May fly in inhabited environment
• May fly above a height of 120 meters
• May drop materials
• May fly beyond visual line of sight (BVLOS)

Drones deployed by the Dutch fire brigade fall under the specific category, and more than likely, will be used by the forestry department. Obtaining authorization for flight needs to be done at the national aviation authority. The Dutch fire department has broader permissions regarding drones because of the fact that they have a specific flight originisation