Satellite connectivity as an enabler of BVLOS UAV operations
Operations of unmanned aerial vehicles beyond visual line of sight, known by the acronym BVLOS, require a continuous, low-latency communications link with sufficient geographical coverage to guarantee command and control of the aircraft, telemetry transmission and, in certain applications, the transfer of high-density data payloads. Terrestrial communications systems present structural limitations in this scenario: cellular coverage is not homogeneous in rural, maritime or mountainous environments, and conventional radio infrastructure was not designed to serve mobile nodes on the vertical axis. Satellite connectivity resolves these coverage constraints by providing a communications plane that is independent of topography and of the density of terrestrial infrastructure. From a technical standpoint, the integration of satellite terminals into UAV platforms imposes weight, power consumption and form-factor constraints that condition the selection of the orbital segment. Low Earth orbit constellations, LEO, offer latencies in the order of tens of milliseconds, compatible with real-time control loops, but require antennas with satellite-tracking capability or electronically steered arrays that add mass and complexity. Solutions in Ku or Ka band over GEO satellites allow for more established terminals, although the latency inherent to geostationary orbit, in excess of 600 ms on the round trip, limits their applicability in direct control modes and directs them towards missions with greater onboard autonomy. In persistent surveillance applications, the satellite link acts as the primary channel for retransmitting video and sensor data to remote operations centres, enabling long-duration missions over extensive areas without dependence on intermediate ground control stations. In unmanned logistics, continuous connectivity is a necessary condition for dynamic route management, coordination with the unmanned air traffic manager and contingency notification. In precision agriculture, bandwidth requirements are lower, but coverage in rural areas without cellular infrastructure makes the satellite link the only technically viable alternative for systematic BVLOS operations. The aeronautical regulatory framework, which is in the process of maturing across multiple jurisdictions, is incorporating explicit requirements on the reliability and integrity of the command and control link as a condition for the authorisation of BVLOS operations. This transfers the technical discussion on satellite connectivity to the domain of operational certification, where concepts such as link availability, channel redundancy and interference management acquire direct regulatory relevance. HAPS platforms, situated in the stratosphere, constitute a complementary architecture that can provide regional coverage with low latencies and a favourable link geometry for UAVs operating at working altitudes, without requiring the orbital infrastructure of a complete LEO constellation.
NASSAT - Network Satellite Systems