Video data links (VDLs) connect a UAV (unmanned aerial vehicle), UGV (unmanned ground vehicle) or other unmanned system to another location, typically a ground control station, for the purpose of transferring video information. This may be done in order to record surveillance or inspection footage of an area, or to provide a live feed for situational awareness and further decision-making. Live video feeds can be particularly important to maintain safety, as with no pilot physically present in the vehicle, the feed may be the only way to observe the vehicle’s surroundings.
Direct transmission of video data from the drone or unmanned vehicle to the base station receiver typically requires line-of-sight (LOS) propagation, meaning that these transmissions cannot reach past the horizon. For non-line-of-sight (NLOS) propagation, often required by long-range military UAVs and BVLOS (beyond visual line of sight) drones, relay stations may be used to extend the communications range, or the vehicle may communicate via SATCOM (satellite communication).
Common radio frequencies for drone video data transmission range from under 1 GHz to around 40 Ghz. Available frequencies for civilian drone use can vary by jurisdiction, with certain frequencies being restricted for military use. In general, higher frequencies provide greater data transfer rates, but have shorter range and are more easily blocked by obstacles.
Drone Video Transmitters for Critical Applications
Wireless drone video transmitters for critical applications such as ISR (intelligence, surveillance and reconnaissance) may need to transmit HD video in order to provide the most detail on their targets. In addition to daytime camera footage, drones may transmit video data from other payloads such as night-vision or thermal infrared cameras. Some systems are capable of transmitting multiple video streams over the same downlink, as well as other information such as metadata, IP data and audio feeds. Digital video data can also be encrypted using techniques such as AES-256, providing additional security.
Bandwidth available for video data links, and the total throughput of data, can vary during the course of a mission, and is influenced by factors such as physical obstacles, environmental conditions, or the transition from line-of-sight to satellite data links. To overcome this, some video transmitters feature automated adjustment of video parameters in order to match varying bandwidth conditions and maintain basic functionality.
In addition to military ISR, drone video data links can be used for a range of commercial and industrial applications, such as infrastructure and utilities inspection, wildfire monitoring, and environmental research. FPV (first person view) video transmitters and receivers are also used for sport drone racing.
Unmanned Vehicles & Wireless Transmitters and Receivers
As the number of sensors on a typical unmanned vehicle increases, as well as the video resolution of these sensors, so does the amount of video data needing to be transmitted. Video compression algorithms can be used to offset this, with the goal being to remove redundant information without sacrificing video quality. The most complex compression algorithms require more powerful onboard processing, and so the video quality and transmission needs must be balanced with the SWAP (size, weight and power) limitations of the vehicle.