Creation of a forest fire monitoring system based on unmanned aerial vehicles

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A wildfire is the spontaneous, uncontrolled spread of fire across a forest area. It has a devastating impact on the environment, landscape and ecosystems. The risk of wildfires grows in extremely dry conditions, such as drought, heat waves and during high winds. Wildfire smoke is a mixture of hazardous air pollutants, such ozone, aromatic hydrocarbons, or lead. In addition to contaminating the air with toxic pollutants, wildfires also simultaneously impact the climate by releasing large quantities of carbon dioxide and other greenhouse gases into the atmosphere. These natural disasters are increasingly extreme in terms of acres burned, duration, and intensity. They can also disrupt transportation, communications, water, power, and gas supplies.

There are three main factors that contribute to the risk of fire occurrence:

• dry fuel such as leaves, grass, branches, and other organic materials
• oxygen in the air
• uncontrolled heat or fire sources

Lightning is the most common ignition source that causes the vast majority of wildfires. There are two types of lightning: cold and hot. Cold lightning is usually of short duration and thus rarely a cause of wildfires. This is not the case with hot lightning: its currents have a lower voltage but occur over a longer period of time. Because of the intense heat it generates, hot lightning accounts for the majority of natural fires.

Humans are also often responsible for initiating wildfires, either accidentally or intentionally.  Human-related events that can ignite fires range from open burning such as campfires, equipment failure, and the malfunction of engines to debris burning, negligent discarding of cigarettes on dry grounds as well as other intentional acts of arson. The latter accounts for one of the most common causes of wildfires. 

Due to climate changes, the frequency and intensity of extreme weather events such as heat waves are gradually increasing. Under such conditions, forest fires can easily occur and spread.

According to statistics over the past few years, wildfires  are becoming more widespread, burning nearly twice as much tree cover today as they did 20 years ago. Forest fires kill more people and burn more land than ever before, as evidenced by data from different parts of the world:

• According to the European Forest Fire Information System (EFFIS), 2021 was the second-worst wildfire season in the European Union since 2000. Damages in 2021 were only surpassed by those in 2017, when over 1 million hectares (ha) burned in the EU.
• In California, six of the twenty largest wildfires in the state's history occurred in 2020. The devastation was so enormous that a new term has even been coined: the world's first "gigafire"-an unprecedented blaze covering more than a million acres.
• In Australia, the so-called black summer wildfire season of 2019/20 consumed an estimated 46 million acres and destroyed nearly 6,000 buildings in the process. Virtually all of Australia, with the exception of the deserts, has been subjected to large-scale wildfires.

Unmanned aerial vehicles and how they can be used

Unmanned aerial vehicles (UAVs), also known as drones, are being widely used and have gained significant attention in the last decade. Most of the studies report multirotors due to their simplicity in control mechanisms and high-precision in positioning. At present, UAVs are being used in multiple military, industrial and commercial applications. They are being used in mobile edge computing, cellular communication, package delivery, smart healthcare, intelligent transportation systems, video surveillance missions, precision agriculture, power-line inspection, remote sensing, search and rescue, and performing relief operations in disaster environments. UAVs have the capability to access remote or dangerous areas, facilitate environmental monitoring and capture high-resolution imagery. These flying objects are helpful in monitoring as they bridge the constraints in limited-access, dynamic, harsh and complex environments.

Application of UAVs in fire fighting

Unmanned aerial vehicles (UAVs) offer several advantages that enhance the safety, efficiency, and effectiveness of firefighting operations. In this section, we will explore the numerous benefits of drones in firefighting. They can reach heights inaccessible to firefighters, improving response times and containment efforts. Meanwhile, the real-time data they obtain on fire behavior, temperature, and smoke patterns help incident commanders and firefighters adjust their strategies and make informed decisions for more effective firefighting efforts. Additionally, drones with thermal cameras detect hotspots and locate trapped individuals. This information helps prioritize efforts, deploy resources effectively, and potentially save lives by identifying those in need of immediate rescue.

Aerial firefighting drones also play a crucial role in facilitating communication and coordination among different teams and agencies involved in firefighting operations. In remote or disaster-stricken locations where communication infrastructure might be damaged or non-existent, drones equipped with communication devices can act as relay points. 

Based on all of the above, we can conclude that drones can seriously help fight forest fires and minimize casualties, because they allow you to control the situation and respond quickly to the threat, so firefighting systems using them will be extremely effective.

Creation of a forest fire monitoring system

The forest fire monitoring system is based on the FlytNow program. It is a cloud-based fleet management solution that provides a unified dashboard for managing a fleet of drones. The dashboard provides access to drone mission planning, live telemetry, and video streams from all connected drones over a 4G/LTE/5G network. Below it is shown an illustration of how the solution works (Picture 1).

A forest fire can burn for days before it can be brought under control, so it becomes important for firegighters to stay aware of the situation and monitor it.

FlytNow offers a drone autonomy software platform specifically tailored for firefighting missions, which helps in setting up a localized command center to manage drones working to bring a forest fire under control. Following are the features that would allow firefighters to set up a command center and some ways they can be used:

• FlytBase can be accessed via a web browser. A firefighter with a laptop can log into the FlytBase dashboard and see the status of all connected drones. Similar to a command center, he/she can manage and control all drones from a single dashboard.
• FlytBase comes with an advanced mission planner that allows for setting up a flight path for a drone. Using the mission planner, a fire official can program a drone to fly over a defined perimeter and map it in order to understand the spread of the fire.
• It can stream live video and telemetry from all connected drones. Using this feature, a fire official can see the video feeds (at ultra-low latency) from all connected drones on the dashboard and even share them with various agencies either via email or using the built-in team management system. This would allow for better coordination among different agencies.

This program makes it possible to organize both general monitoring of any area and search for specific problems, for example, search for fires or other natural disasters. All data collected in varioust surveillance modes are transmitted to the command center. It should be noted that the entire patrolling process can be carried out both fully autonomously and under direct human control.

The system includes two types of UAVs: hexacopters and airplanes, which perform different types of tasks. Regarding the onboard sensors, the UAV was equipped with a set of subsystems described as follows:

• Optical sensors
• Thermal camera
• Digital temperature sensors
• Onboard embedded unit
• Communications module

The system uses Leica Aibot hexacopters, multifunctional vehicles perfectly suited for patrolling territories. They can lift 6 kg of payload into the air, and fly with it for 28 minutes at an altitude of more than 4 kilometers. This is more than enough for patrolling. The main characteristics of these aircraft are as follows:

• Take-off weight: 15.1 kg
• Flight altitude: up to 4500 meters
• speed: 50 km/h
• Climbing speed: 28 km/h
• Flight time: up to 24 minutes

The system also includes the SenseFly eBee Classic airplane-drone. It is a fully autonomous and easy-to-use mapping drone. The EBee Classic is the easiest to use mapping drone available, you just need to toss the drone in the air to take off, which allows you to use it on any terrain. With a light weight and a wingspan of less than a meter, this drone can be launched even from a small open area, which is convenient when monitoring forests. It has the following characteristics:

• Wingspan: 0.96 meters
• Weight: about 0.69 kg
• Cruising speed: 40-90 km/h
• Maximum flight time: 55 minutes

In the established firefighting system, FlytNow is integrated with ground equipment and computerized dispatch systems such as emergency services. The operation of the system is as follows:

1. The forest area to be patrolled is divided into squares, which are calculated based on the capabilities of the UAV. Using Microsoft Excel software, it was calculated that for the most effecient patrolling by our hexacopter, the side of the square should be 2.5 km.
2. The points on the perimeter and inside the square have digitized geographic coordinates.
3. Based on the geographic coordinates and patrol tasks, different routes for UAVs are programmed.
4. A database of routes for drones is formed.
5. A forester goes out on patrol with several drones. He moves along the borders of the squares by launching a drone into any of them, having previously selected a route for this drone. Several batteries are provided for each copter, which greatly increases the patrol time of one UAV.
6. The data from the drone's cameras is transmitted to the dispatcher at the command center. It is possible to use artificial intelligence functions, such as object detection, to identify specific ground targets, such as a hot spot.
7. If a fire is detected, the dispatcher will call the fire department and report about the fire.
8. The drone continues the mission until its battery runs out. It returns to the station and lands to recharge using the precision landing feature. A ranger's transport can be used as a charging station.

There are three types of routes:

1. Perimeter flight. The drone flies  only around the perimeters of squares.

1. Full patrol. The drone surveys the entire square.

1. Back and forth overflight. The drone flies to the maximum allowable range, flies 200m to the side and comes back.

The parameters of the routes are also given in the table (Table 1). Here you can see the time spent on each route for a hexacopter and for an airplane. The area viewed by drones when performing a task is also calculated. The airplane flies over a larger area, but inspects it in less detail. The hexacopter, on the other hand, monitors the area in great detail.

Table 1. Parameters of the routes

Conclusion

Based on the data obtained of using drones when extinguishing forest fires, we have created a fire fighting system based on UAVs. We have also described in detail the principle of its operation. The most suitable aircraft parameters have been selected and patrol routes have been calculated for various methods of using the presented system. Since the system created during the work is quite simple, it can be used locally, in individual areas of the forest, and throughout the entire forest area. Since this firefighting method can be applied now, this is a good opportunity to get closer to solving one of the most important firefighting problems, at least in some regions. 

About the authors

Nikita Alekseevich Voronin

Author for correspondence.
Email: voroninn2004@mail.ru
Russian Federation

Svetlana Albertovna Avdeyko

Email: asa210770@mail.ru

References

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