Beyond Visual Line of Sight (BVLOS) operations are those in which the remote pilot does not have the RPA in direct sight during a flight mission. This includes two situations: the first is when the RPA is too far away for the remote pilot (RP) to see it, even though a straight path exists between them and there is Radio Line of Sight (RLOS); the second is when there is no straight path between the RP and the RPA because of obstacles (eg buildings, terrain) or because the RPA is over the horizon.
While some BVLOS operations can be conducted using radio frequencies such as VHF (with or without radio relays) many operators, such as the military, routinely use satellite communications for flight control and payload communications.
Further Reading
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