An infrared thermal sensor from FLIR has been integrated into a compact UAV to give customers thermal vision capability.

Based in Denmark, Sky-Watch designs and manufactures quad-rotor UAVs for military, law enforcement, security, firefighting, and search and rescue applications. Sky-Watch has integrated a FLIR Quark 640 longwave infrared thermal sensor into their Huginn X1 drone to give customers a thermal vision option. Originally developed to manage a single payload, the X1 has been designed to carry a dual payload capable of simultaneously operating a Quark thermal camera core and a visible spectrum camera, thanks to the Quark’s compact size.

Finding the right thermal camera core
Sky-Watch caters to customers within the emergency management segment, which covers fire brigades, police, security, and search and rescue. All of their customers share a common need to see at night so they can find missing or camouflaged people. Night vision cameras were too bulky for their platform. According to Michael Messerschmidt, Sky-Watch Business Development Manager, thermal is a more effective option for base protection and compound protection.

After surveying the market for the right thermal camera core to use on the X1, Sky-Watch chose the Quark because of its size and form factor. Messerschmidt explains it has a very good centre of rotation; its small size allows them to place a daylight camera and thermal camera next to each other, enabling dual sensor capability, which is unique on this small platform.

Integrating Quark into Huginn X1
Once Sky-Watch selected Quark as its thermal payload, they faced a few challenges integrating the core into their system. They initially tried to design their own interface board to power the core and stream video. However, their design created too much noise so they turned to the VPC interface board FLIR designed specifically for Quark and found that it worked perfectly.

The second challenge involved calibration, or flat-field correction (FFC), which is necessary to maintain a more uniform thermal image. Since Quark does not have a shutter, an FFC must be performed using an external reference source. Sky-Watch solved this by developing a pan/tilt on the Quark that tilted it inward to face a ‘flat field’. This action sends an FFC command to Quark to correct the image. Quark initially calibrates whenever it’s powered on, but the X1 drone operator can initiate an FFC calibration at any time from the user interface.

Once Sky-Watch plugged into the Quark VPC, they created all the controls and software that operated the camera. From a ground station, an operator can control X1 from more than a mile away with the user interface.

Control features include video recording via live feed on the ground station computer; designating a waypoint route and points of interest on the way prior to launch; and guide in real time based on live video feedback.

Flight time for a single payload is 23 to 24 minutes; for a dual payload that time drops to about 21 minutes.

Sky-Watch also added another layer of protection for the Quark by designing the X1 with a front-mounted payload. Many small drones have bottom-mounted payloads that can get damaged during a hard landing or crash. When the X1 lands, the Quark automatically turns upwards from the ground to protect the lens.

Quark gives Sky-Watch a competitive edge because it increases flight time. X1 is the only platform of its size that weighs less than 1.5kg and has dual sensor capability. That’s a major selling point and another reason Messerschmidt always brings his Quark on sales calls to perform demonstrations.

The Huginn X1 quad-rotor UAV integrated with a Quark 640 longwave infrared thermal sensor has been received extremely well in the market, thanks to its combination of size, performance, and thermal capability.

FLIR thermal imaging cameras are available in Australia from FLIR Infrared Cameras & Thermal Imaging .