Classification of unmanned aerial vehicles

A drone is an unmanned aerial vehicle (UAV) designed to perform various tasks. In the civilian sector, these devices are used for photography/video footage, transportation of goods, and inspections of facilities. The product lines of UAVs for various tasks are constantly expanding. To help better understand their diversity and varieties, unmanned aerial vehicles are categorized based on specific attributes. This type of systematization helps us correctly develop security tools to protect against them.

Kaspersky experts developed their own classification system for drones used by civilians. This classification system is based on the level of damage that could be inflicted by the UAV. This approach is important for designing systems geared toward protection against aerial vehicles.

According to this developed classification system, experts distinguish four different groups of drones:

• Moderate threat level. These UAVs have their factory firmware with no other modifications, and communicate at the 2.4 GHz frequency. These drones are equipped with Remote ID technology, which means that they use radio signals to continuously broadcast their coordinates, serial number, and take-off location.
• Medium threat level. These UAVs have more complex control mechanisms and are able to hide their own location and the location of the pilot. This creates difficulties when developing a defense against them.
• High threat level. These UAVs are capable of operating in multi-channel mode and are equipped with powerful communications systems that are resistant to interference.
• Critical threat level. This group includes the following: airplane-type and helicopter-type devices, FPV drones, LTE drones, and custom-built drones. These UAVs fly without a control system and are characterized by their autonomy. The necessary coordinates of their flight path are programmed in advance.

The classifier used by Kaspersky Antidrone considers the firmware versions, hardware modifications, communication channels, and a number of other characteristics.

Protection of industrial enterprises

Protection of large-scale events

Protection of airports

Protection of energy facilities and oil refineries

UAV classification based on potential threats is necessitated by the heightened importance of knowledge about these specific threats. This classification makes it easier to choose effective protection against drones, ensure safety and security, and create a conceptual field for manufacturers, customers and operators of protected facilities.

Other methods of categorizing drones

After UAVs emerged, we soon saw them divided into many varieties and categories. This categorization is done by using various attributes and parameters, such as their design, purpose, weight, dimensions, and flight characteristics.

Distinguishing characteristics of drone operating mechanisms

UAV classification based on their design is the most popular and practical method of classification. Based on this attribute, they can be distinguished as follows:

• Airplane-type units;
• Single-rotor and multi-rotor units;
• Aerostat units;
• Convertiplanes and other hybrid devices.

A copter drone with one or more rotors may also be called a helicopter-type drone because it uses rotors during its operation. A drone with four motors and propellers is known as a quadcopter. This is the most commonly used option for multi-rotor drones that operate based on the principle of helicopter flight. There is a separate classification for quadcopters based on their dimensions and number of rotors. These vehicles are actively used for all kinds of different tasks. Multicopters are used for games, photography/filming, surveillance, event organization, industrial and logistical operations.

Aerostat drones

These types of drones use the Archimedes principle of buoyancy to remain in the air. This buoyancy occurs due to the difference in density within and outside of the vessel. These airborne vessels are essentially large shells filled with gas that is lighter than air, such as helium or hydrogen. Various payloads are attached to these drones.

Main advantages of aerostat drones:

• Remain in the air for prolonged periods.
• Handle tasks requiring prolonged surveillance, monitoring and relay of signals over extensive territories.
• Are relatively simple in design and inexpensive.

Shortcomings: Low maneuverability, incapability of quick movements, and vulnerability to weather conditions.

Hybrid devices

These units include elements of rotor-type and airplane-type designs and combine the advantages of various operating methods. They are equipped with multiple rotor mechanisms for vertical takeoff and landing, and have fixed wings for horizontal movement. This combination supports increased speed, movement over large distances, and prolonged flight time while maintaining precise maneuvering capabilities. Convertiplanes are one example of hybrid drones. Their propellers can rotate 90 degrees to allow the unit to transition from a vertical takeoff to horizontal flight. Other models use fixed wings and several small rotors positioned along the drone body. This architecture ensures maneuvering capability and efficiency of take-off/landing and flight.

Hybrid drones are faced with a few technical challenges. These challenges include the reliability and safety of their complex mechanical systems, integration of various power mechanisms, and optimization of their load distribution.

Aircraft performance characteristics

Each type of device has its own specific aircraft performance characteristics, such as its takeoff weight, altitude, range, and flight time. These characteristics make it easier to find the right model for you when considering its capability to perform the relevant tasks. UAV classification based on aircraft performance characteristics was developed more than 20 years ago by UVSI, which is an international association dedicated to drones. Its full name is Association for Unmanned Vehicle Systems International.

Among its distinguished categories of unmanned vehicles, the civilian categories include the following:

• nano: mass of up to 250 grams, flight altitude of 100 m to 1 km, and a flight time of approximately 30 minutes.
• micro: up to 5 kg, flight altitude of 230 m to 10 km, and a flight duration of 60 minutes.
• mini: up to 150 kg, flight altitude of 150–300 m for a distance of 30 km, and a flight duration of at least 120 minutes.

The Russian UAV classification is often used nowadays. It distinguishes the following categories:

This category includes devices that are easy to control, can be tracked, and perform simple operations.

Main indicators of these types of drones

Drones with a moderate threat level operate at the same frequency of 2.4 GHz, which makes them easier to detect. These models adhere to the European CE radiocommunication standard and use Remote ID technology, which identifies the location of the pilot and the coordinates of the drone.

Other characteristics:

• Firmware: factory
• Weight: less than 250 g and up to 150 kg
• Purpose: for domestic use, surveillance, photography, filming, and providing services for weddings, concerts, and other large-scale events.
• The payload of large models can be over 10 kg.
• Flight range: short

These types of units normally have large dimensions and are inexpensive.

Operating scenario

The drone is controlled from a console that sends all of the necessary commands and defines their execution format. This does not require a lot of experience. The drone functionality depends on the complexity and purpose of the drone model.

Although these drones are more expensive, you can purchase them at marketplaces and in specialized stores. The devices are distinguished by their radio channel with a frequency band ranging from 2.4 to 5.8 GHz. They support two-channel operations, which create difficulties when trying to neutralize them with antidrone resources. Multicopters and other units either provide the capability to disable the Remote ID system or this system is completely excluded from the design. This factor helps conceal the coordinates of the unit and its pilot. Instead of standard CE, these units use a boosted signal in FCC mode, which provides more resistance to interference.

Полезная нагрузка связана с массой самого аппарата:

• Model up to 2 kg: less than 1 kg
• Up to 25 kg: over 1 kg
• Up to 150 kg: over 10 kg

The flight range of these UAVs is several kilometers. Their purpose is the same as moderate-threat drones but with extended capabilities and functionality.

These are usually UAVs with industrial applications. They have larger dimensions and are capable of servicing oil refineries, industrial and agricultural facilities, and infrastructure systems. These models have a significant weight of up to 150 kg or more, and are capable of transporting a payload weighing over 10 kg.

This type of unmanned aerial vehicle provides the option to use a frequency of 900 MHz, 2.4 GHz, 5.2 GHz, or 5.8 GHz, and are able to use 4-channel mode. Remote ID is either disabled on these drones or is not included in the design. These devices are equipped with a powerful hardware-amplified transmitter operating at around 1 Watt. This increases their resistance to interference and requires more neutralization efforts from state-of-the-art antidrone equipment.

When malicious threat actors use this type of UAV, the security threat is much more serious because it is quite difficult to counteract these units and protect against them using antidrone resources.

These drones include the following models:

• Airplane-type drones that operate without a radio channel and instead use GPS, GLONASS or the Chinese BeiDou system, or use an inertial navigation system (INS).
• FPV units.
• LTE drones controlled via cellular communication.

This threat category also includes multicopters and airplane-type designs that are custom-built by amateur enthusiasts.

Critical-threat drones typically require a high level of training for their pilots because it is more complicated to control these drones. In some cases, the weight of these devices may exceed 150 kg.

Airplane-type UAVs

Drone models with an airplane-type design are usually called 'fixed-wing' units. These devices typically have an increased range and flight time, and enhanced speed and altitude capabilities. These units are simple to maintain and are relatively inexpensive.

Airplane-type drones are capable of flying without GPS and can use an inertial navigation system instead. This system includes hardware and software components and ensures autonomous movement of the unit. It works based on the law of inertia. Sensors measure the acceleration of the device and its angular velocity, while specialized programs process this information and issue commands based on the results. Although this form of navigation is not the most precise, it ensures autonomy and eliminates the possibility of commands or signals being intercepted.

FPV drones

First Person View (FPV) devices are a special class of unmanned aerial vehicles that are designed to be controlled by their pilot in real time. These drones are equipped with miniature video cameras and transmitters that enable them to relay video from the device to a ground-based station. The pilot uses special goggles or a display monitor and sees exactly what the drone sees. This creates the effect of presence as if the pilot is on board the drone. FPV systems are quickly gaining popularity among enthusiasts and amateur aerial photographers. From the air, they transmit dynamic frames that are not accessible to traditional cameras. FPVs are distinguished by their high maneuverability and speed.

LTE devices

LTE (Long-Term Evolution) drones utilize 4G cellular networks to communicate with their ground-based control station. This approach significantly expands the operational range and capabilities of the drone when compared to traditional systems that are limited by the direct line of sight of the operator.

LTE technologies support sustained bidirectional communication at distances of up to several dozen kilometers. However, they also depend on the quality of the local cellular infrastructure. They provide the capabilities to employ drones for monitoring extensive territories, urgent deliveries of goods, and aerial reconnaissance.

In addition to expanding the operating range, LTE drones have a number of other advantages, including the capability to do the following:

• Transmit high-quality video in real time.
• Receive commands and telemetry.
• Update their own software.

A cellular network provides more secure and fault-tolerant communication when compared to radio channels of ordinary systems.

Custom-built and improvised drones

One of the growing threats in the field of drone technologies are custom-built or home-made drones that are created for various purposes. They are assembled from readily available components and may carry a payload ranging from spy cameras to contraband or even explosives.

Due to their cheap materials and relatively simple assembly, UAVs are becoming a popular tool for illegal and destructive purposes. Their lack of a serial number and capability for anonymity make them even more dangerous. These types of systems have already been employed for attacks against government facilities, mass concentrations of people, and objects of critical infrastructure.

Modern classification of unmanned aerial vehicles is multifaceted. It covers their type, size, aircraft performance characteristics, purpose, use of various devices, and many other factors. This system of classification includes mass consumer units and high-tech systems for industrial applications.

In addition to accomplishing current technical, logistical and production tasks, drones may also pose risks for industrial enterprises, large-scale events, and critical urban infrastructure.

The growing threat associated with home-made or improvised drones is also causing serious concern because they are being used more and more for illegal purposes. According to our classification, these UAVs pose a critical danger and require elevated attention to antidrone protection measures.

An effective response to these challenges requires a comprehensive approach, which includes improvement of the legal and regulatory framework, development of UAV countermeasure technologies, and active international and industry-wide collaboration.

The business community and individual enterprises must also become familiar with the types of drones and their potential threats, and understand the 'infringer model' for civilian facilities. Thanks to the classification of quadcopters according to their purpose and threat level and the division of variously designed units based on these criteria, we can prioritize our vectors of protection against the negative impact from drones.