BLOS and satcom data links for drones

Beyond line-of-sight (BLOS) links keep the aircraft connected when it is beyond the range of a direct radio link: over the horizon, behind terrain or hundreds of kilometres away. They use satellite networks or terrestrial cellular networks, and are essential for long-range and BVLOS operations.

Technologies

• LEO satellite (low Earth orbit): global coverage with small antennas and relatively low latency. Narrowband services suit C2 and telemetry; broadband LEO services carry video.
• GEO satellite (geostationary): high throughput, but larger antennas, higher latency and limited coverage near the poles.
• Cellular (LTE/5G): low-cost connectivity where networks exist, with coverage at altitude that varies by operator and area.
• Multi-link routers: combine several networks and switch or bond them automatically.

Key specifications

• Coverage of the operating area.
• Data rate and latency: enough for C2, telemetry or video.
• Terminal size, weight and power, and antenna type (patch, phased array, steerable).
• Service cost and plans.
• Security and encryption.
• Certification: some satellite services are approved for aviation safety communications.

Choosing

For C2 and telemetry on long-range UAVs, a compact LEO terminal is often enough. For live video beyond line of sight, broadband satellite or cellular are needed. Many operators combine a LOS link for the area around the base with a BLOS link for the rest of the mission.

Manufacturers in the directory

Examples include Iridium, Viasat (Inmarsat), Cobham Satcom, Elsight and Get SAT.