Satellite Communications for Drones & UAV
UAV and unmanned vehicle SATCOM is primarily used for providing BVLOS (beyond visual line of sight) capabilities. Standard line-of-sight datalinks will be rendered unworkable at great distances due to the curvature of the earth, and drones may also fly out of range of ground networks such as 5G and other cellular services. A satellite can be used to relay and amplify radio or microwave frequency signals between the vehicle and its base station.
SATCOM satellites are usually in geostationary orbit, where they appear at a constant position in the sky, or in Low Earth Orbit (LEO), where they appear to move. LEO satellites are at a lower altitude than geostationary satellites, meaning that they will provide less latency, but geostationary satellites have the advantage of not needing to be tracked.
SATCOM Frequency Bands
Satellite communications are split into different frequency bands. In increasing order of frequency and decreasing order of wavelength, these are L-band, S-band, C-band, X-band, Ku-band and Ka-band. Higher frequency bands usually provide greater bandwidth, but are also more susceptible to signal degradation due to signals being absorbed by atmospheric rain, snow or ice. X-band is typically used by the military as a compromise between these two factors.
Drone SATCOM is often used to transmit critical ISR (intelligence, surveillance and reconnaissance) data from faraway UAVs, in situations where decision-makers require real-time or near real-time access to the data and cannot afford to wait for the aircraft to return. It is also used to create secure, reliable C2 (command and control) links between unmanned vehicles and GCS (ground control stations), allowing users to monitor status, remotely control the vehicle, and switch between remote control and autonomous operation.
Unmanned vehicle and drone SATCOM can utilise a variety of different services, such as Inmarsat and Iridium, which have different global coverages, uptime percentages and bandwidth capabilities.
UAV SATCOM terminals provide an all-in-one solution for transmitting, receiving, and satellite acquisition and tracking. Lightweight, compact terminals are available that have been specially designed for the SWaP (size, weight, and power)-conscious needs of UAVs.
Satellite communication antennas for drones are designed so as not to create significant aerodynamic drag or add excessive mass to the aircraft. They must have sufficient gain to support high enough data rates for a required application.