Tethered Drones

Tethered drones, also known as tethered UAVs (unmanned aerial vehicles) or tethered UAS (unmanned aircraft systems), enable sustained flight and uninterrupted data transmission, with exceptional operational reliability where only a minimal operating area is needed.

Unlike traditional free-flying drones, by connecting to a ground-based power source via a robust tether, tethered UAVs offer extended endurance and continuous deployment, making them ideal for missions where long-duration operations and real-time communication are critical.

How Tethered Drone Systems Work

Khronos Tethered Drone by Elistair

Tethered drones operate through a physical connection—a flexible wire or cable—linking the UAV to a power source. These systems typically use quadcopters or other multirotor drones, as well as aerostats, as fixed-wing drones lack the capability to hover. The tether, constructed from lightweight materials like aramid with integrated copper or optical fibers, provides power, secure data transmission, and communications. Drone tethers typically provide up to a few hundred metres of operational altitude, with the limiting factor being the ability of the drone to support the weight of the tether.

Ground stations supply power from mains electricity or generators, with battery backups for reliability. Advanced tethered UAV systems incorporate automated tether winding, GNSS positioning, smart power management, and built-in fail-safes for consistent performance in challenging conditions.

Applications of Tethered Drones

The unique capabilities of tethered UAVs make them invaluable across various sectors, including:

• Persistent Surveillance: With high-resolution imaging systems, tethered drones deliver uninterrupted monitoring for military intelligence (ISR), border security, event management, disaster response, and critical infrastructure protection.
• Communications Relay: Serving as aerial nodes, these systems establish temporary communication networks for cellular, radio, and broadband signals in remote or disaster-stricken areas.
• Industrial Inspections: Equipped with stable, high-resolution imaging capabilities, tethered drones support detailed assessments of facilities like oil rigs, power plants, and other industrial sites.

Ongoing research explores innovative uses, such as power generation through wind energy harnessed by UAV tether systems.

VULTURE Tethered Maritime Drone by DPI UAV Systems

Key Features and Advantages

Tethered drones offer significant advantages over traditional free-flying UAVs, including:

• Continuous Power Supply: The tether eliminates battery limitations, allowing for indefinite operation, restricted only by the ground station’s power source.
• Secure Data Transmission: Data transmitted via fiber optic cables in the tether is highly secure, immune to jamming or interference common in wireless systems.
• High Payload Capacity: These drones can support a range of mission-specific payloads, such as EO/IR cameras, LiDAR sensors, radio repeaters, and environmental sensors.
• Exceptional Stability: The anchored design and advanced flight control algorithms ensure robust stability, even in adverse weather conditions.

Considerations for Tethered Drone Systems

When selecting a tethered UAV system, important factors include operational altitude, tether length, power source capacity, payload compatibility, and deployment speed. Modern systems are designed for portability and rapid deployment, with some offering automated spool systems to dynamically adjust the tether based on flight requirements.