Over the past decade, unmanned aerial systems (UAS) have evolved from a niche tool to a mainstream capability in public safety. Today, certified pilots deploy drones for search and rescue, tactical operations, infrastructure inspections, hotspot detection and more. Many agencies also use Drone as First Responder (DFR) programs, launching drones from pre-set locations to gain early situational awareness before ground units arrive.
But as departments lean on drones for more routine overwatch – from parades and concerts to stadium events and large-scale gatherings – the traditional model has limits. Weather, airspace restrictions and battery life can all affect whether a free-flying drone can launch, stay up and deliver a reliable view for an extended period. Pilot availability can be another constraint, especially amid staffing shortages.
An actively tethered drone overcomes these limitations and more.
With major special events on the horizon, including the 2026 FIFA World Cup, agencies are treating event planning as a continuous, intelligence-led discipline. That shift increases the need for persistent aerial awareness that can be deployed quickly and maintained for extended periods, even when conditions are less than ideal.
Designed to fly tethered – with power and data running through the tether – actively tethered drones trade range for endurance, simplified operation and a stable overhead view that can be shared with responders and command staff, while still operating within applicable policies and airspace requirements.
What is an actively tethered drone?
“An actively tethered drone isn’t simply a free-flying aircraft with a line attached. It’s purpose-built to operate tethered, with power and data running through the tether to enable persistent, reliable aerial awareness,” explained Chris Martorana, international sales and marketing director at Fotokite, a Swiss company with U.S. headquarters in Colorado that develops actively tethered aerial awareness systems for first responders.
A tethered drone doesn’t have the range of a free-flying drone but for many use cases, it doesn’t need it. Instead, an actively tethered drone is built for rapid deployment and persistent overhead awareness, with the ability to stay aloft for extended periods and operate in conditions that can ground other aircraft.
Just as important, the interface is designed to reduce the training burden. In many operational contexts, any public safety professional can launch, fly and land the system without the same licensing requirements typically associated with UAS operations, making it possible to use when certified pilots aren’t available.
Introducing the Sigma+ actively tethered UAS
Fotokite’s signature product, the Sigma+, is a lightweight, actively tethered UAS for first responders. It features a wide-angle color camera, a zoom color camera and an optional IR+ thermal camera, mounted on a three-axis gimbal. Fotokite also offers API integrations, allowing departments to integrate Fotokite into their existing workflows and software systems.
Video from the high-resolution sensors is delivered through a simple-to-use interface on a Dell Pro Rugged 10 Tablet. The livestream can also be shared with up to 50 viewers via a secure link, extending mission-critical awareness to responders on the scene as well as command staff, mutual aid partners and other stakeholders.
Deployment is designed to be straightforward. The Sigma+ can be launched, flown and landed at the touch of a button from a vehicle-mounted Rooftop Box rated IP55 for operation in wind, snow and rain. For agencies that need flexibility beyond a vehicle mount, Fotokite also offers a portable Transport Case for rapid setup in a wider range of locations.
All these features add up to a highly capable drone for overwatch, but what makes the Sigma+ operationally distinct is the tether itself.
The tether is more than a cable that keeps the drone in place – it’s the system’s nerve center.
Advantages of an active tether
The active tether provides several advantages over free-flying drones for overwatch.
1. Continuous power
When connected to the ground unit, the active tether provides continuous power to the drone – roughly 400 to 600 watts – enabling virtually unlimited run time.
While free-flying drones must land regularly for battery changes, the Sigma+ remains aloft and operable as long as the vehicle is running or the unit is plugged into shore power.
“We’ve seen systems remain airborne for more than a month without landing,” said Martorana.
2. The tether as conduit
The tether also serves as a hardline connection for live color and thermal video. Video can be streamed locally via Ethernet or encrypted Wi-Fi or shared remotely using the system’s integrated LTE modem.
The direct Ethernet connection between the drone and the Dell tablet ensures connectivity even in a GPS-degraded or GPS-absent environment. This enables a persistent overview even in the absence of a cellular or Wi-Fi connection, ideal when operations move into challenging environments like cellular dead zones, urban canyons, airports, crowded stadiums or natural disaster zones.
The tether also supports better-quality video. “The closed Ethernet loop delivers consistently crisp imagery because the connection is hard-wired directly to the aircraft rather than relying solely on cellular,” Martorana added.
3. The tether as a controlled safety envelope
The tether’s managed spool and tension control help the aircraft hold position and altitude, even in wind, while maintaining a consistent safety perimeter.
The tether’s maximum length is 45 meters, keeping the aircraft below 150 feet – a ceiling that falls below FAA requirements for higher-altitude operations. This allows agencies to maintain continuous, hands-free aerial awareness without requiring a dedicated drone pilot to stay on the controls throughout an incident, and it also expands where the drone can operate.
Martorana explained, “For most public safety programs, this technology can be deployed by trained personnel without requiring a dedicated drone pilot.”
Use cases
With personnel shortages across public safety, a situational awareness tool that is quick to deploy – and simple enough to operate without tying up a dedicated pilot – can help agencies add capability without adding complexity.
Fireground intelligence and hotspot detection
For the Merrill Fire Department in Wisconsin, a tethered UAS quickly proved useful for hotspot detection, Chief Joshua Slug told news station WAOW.com. “We can throw it up quickly when we get on scene and not have to worry about it. It gives our IC a bird’s eye view of what’s going on.”
In addition to helping crews size up a roof for hotspots without putting personnel on top of a building, even modest elevation can give command staff a clearer view to direct fireground operations. Dual cameras can also detect and stream valuable intelligence through smoke or darkness, helping crews evaluate whether hose lines are reaching their target and monitor movement into and out of the structure.
Post-incident monitoring and hazardous environments
Fotokite also gives fire crews a self-piloting way to inspect and monitor a post-fire scene for flareups, assess a hazmat situation or natural disaster from a safe distance or search rugged terrain for victims of a vehicle crash – even in weather that would hinder other rescue efforts.
Fotokite gives fire crews a self-piloting way to inspect and monitor a post-fire scene for flareups, assess a hazmat situation or natural disaster from a safe distance
Fotokite
Search operations in low visibility
In Buffalo, New York, within hours of acquiring their Fotokite, police used the thermal imaging capabilities to quickly locate a missing person in snowy, freezing conditions. “The drone was launched and using infrared capabilities within a matter of a couple of minutes,” said Commissioner Joseph Gramaglia. “They were able to identify an anomaly, a heat source, through that infrared that led one of our drone operators to walk directly through that path and we located this missing vulnerable person.”
Event overwatch and soft-target security
Beyond emergencies, tethered overwatch is increasingly used for crowd-focused events that can be soft targets – parades, concerts, festivals, community events, marathons and sporting events. Although the tether can extend to 150 feet, in many cases 60 to 70 feet provides enough height to add context and improve coordination without overwhelming the scene with equipment or staffing demands.
“We now have more than 1,000 units deployed in the field,” said Vanessa White, a former police officer and sales and marketing operations manager at Fotokite, “and the majority of them are used daily for event overwatch across federal, state and local public safety agencies.”
Major events like the 2024 New Year’s Eve celebration in New York City and a massive street parade in Zurich, Switzerland have also served as grounds for event overwatch. In preparation for hosting events related to the 2026 FIFA World Cup, Dallas Police Department has obtained a fleet of Fotokites to support aerial awareness for events expected to draw millions of visitors to the region.
Why the tablet is part of the system
Because the viewing device is central to how the Sigma+ is operated and how video is shared, Fotokite includes a Dell Pro Rugged 10 Tablet with the system.
“We include a dedicated Dell rugged tablet to simplify deployment,” said White. “The application comes fully configured and delivers the reliability and durability first responders need.”
In field use, the Dell Pro Rugged 10 Tablet is viewable even in direct sunlight and the screen is glove-touch capable – practical features for responders working a scene. It’s enabled with Wi-Fi 7 and optional 5G, including private 5G.
“We’ve evaluated a wide range of tablets, and the Dell rugged platform has consistently delivered the connectivity and reliability our customers depend on,” said White. Martorana echoed that the end-user experience is highly important. “The customer experience with the Dell platform has consistently been best-in-class. Our focus is on delivering the high-quality experience our customers expect.”
Expanding aerial awareness beyond traditional drones
Public safety agencies have invested heavily in UAS programs, but traditional drones aren’t always the right answer for missions that demand persistent overwatch – especially when staffing, weather, battery cycles and connectivity constraints collide.
An actively tethered UAS takes a different approach: it trades range for endurance, stability and simplified operation, providing a continuous overhead view that can be shared broadly to build a common operating picture.
As agencies prepare for major events and evolving threats, tools that can be deployed within minutes, operated with minimal overhead and kept in place for extended periods can help leaders make faster, better-informed decisions on the ground.
“There’s a significant amount of effort that goes into our technology behind the scenes to keep the experience simple and easy to use,” said Martorana. “Our goal at Fotokite is to remove many of the barriers departments face when adopting and using UAS.”
For more information, visit Fotokite.
