US Patent 11687072 Automatic UAV landing pad

An unmanned aerial vehicle (UAV) navigation system includes a portable, ground-based landing pad comprising having a first antenna configured to transmit a data packet; a UAV comprising a second antenna configured to receive the data packet; and second processing circuitry configured to determine a signal strength between the first antenna and the second antenna; determine, based on the signal strength, an orientation of the vehicle relative to the landing pad; and determine, based on a time of flight of the data packet, a distance between the vehicle and the landing pad.