Drone with dynamic antenna diversity
The drone comprises M antennas, with in particular two offset antennas located symmetrically at the ends of two arms for the connection to the propulsion units ( 24 ), and a ventral antenna under the drone body. The radio transmission is operated simultaneously on N similar RF channels, with 2≤N<M. An antenna switching circuit couples selectively each of the N RF channels to N antennas out of the M antennas according to a plurality of different coupling schemes, dynamically through a piloting logic selecting one of the coupling schemes. The selection is operated as a function of a signal delivered by the drone-borne microprocessor, as a function of the flight and signal transmission conditions, determined at a given instant.
1. A drone comprising:
a drone body;
a digital controller circuit;
a radio-frequency (RF) transmitter stage comprising a baseband processor circuit adapted to deliver an RF signal to be transmitted; and
M fixed antennas integral with the drone body, wherein the RF transmitter stage further comprises:
an RF dispatcher stage, receiving as an input the RF signal to be transmitted and delivering as an output N RF supply signals, with 2≤N<M;
an antenna switching circuit, adapted to selectively couple each of the N RF supply signals to each of the N antennas out of the M antennas according to a plurality of different coupling schemes; and
logic piloting the antenna switching circuit and adapted to both dynamically determine one of said coupling schemes as a function of a selection signal delivered by a control circuit, and also dynamically determine one of said coupling schemes also as a function of a synchronization signal delivered by the baseband processor circuit, the logic inhibiting the application of the selection signal to the antenna switching circuit at least for the duration of transmission of a frame of RF signal to be transmitted.
2. The drone of claim 1 , wherein the supply signals comprises two RF supply signals and the M fixed antennas comprise three antennas.
3. The drone of claim 2 , wherein the antenna switching circuit is adapted to selectively couple:
a first RF supply signal to either one of a first antenna and a third antenna, and
a second RF supply signal to either one of a second antenna and the third antenna.
4. The drone of claim 2 , wherein the first antenna and the second antenna are lateral antennas positioned symmetrically on either side of the drone body, and the third antenna is a ventral antenna positioned under the drone body.
5. The drone of claim 1 , wherein the supply signals comprise two RF supply signals and the antennas comprise four antennas.
6. The drone of claim 5 , wherein the antenna switching circuit is adapted to selectively couple:
a first RF supply signal to either one of a first antenna and a third antenna, and
a second RF supply signal to either one of a second antenna, the third antenna and a fourth antenna.
7. The drone of claim 1 , wherein the RF dispatcher stage comprises N similar front-end RF modules, each receiving as an input the RF signal to be transmitted and delivering as an output one of the N RF supply signals.
8. The drone of claim 1 , wherein one at least of the N RF supply signals comprises a first signal component in the band 2.4 GHz duplexed with a second signal component in the band 5 GHz.