Unmanned aerial vehicle (UAV) beam forming and pointing toward ground coverage area cells for broadband access
Systems and methods configured to form and point beams from an unmanned aerial vehicle (UAV) toward target cells in a coverage area on the ground. One embodiment determines and forms the required number of UAV fixed beams needed to cover the target area when UAV is at its highest altitude and highest roll/pitch/yaw angles so that the target coverage area is covered under all UAV altitude and orientation conditions. In another embodiment, UAV determines the beam pointing angles toward different cells on the ground using information on position coordinates and orientation angles of the UAV, and the position coordinates of the cells in the coverage area relative to the center of coverage area. In another embodiment, a reference terminal placed at the center of coverage is used by the UAV to optimally point a beam toward center of the coverage area.
1. An unmanned aerial vehicle (UAV) apparatus configured to form antenna beams toward at least one target coverage cell, comprising:
an antenna fixture configured to form at least one beam;
a set of radio transmitters and receivers configured to transmit and receive signals to a set of ground terminals within the at least one target coverage cell;
a processor sub-system; and
a non-transitory computer readable medium comprising one or more instructions which, when executed by the processor sub-system, is configured to cause the UAV apparatus to:
generate the at least one beam that covers the at least one target coverage cell; and
wherein the generated at least one beam encompasses at least one ground terminal of the set of ground terminals;
wherein the non-transitory computer readable medium is further configured to cause the UAV apparatus to store one or more first position location coordinates corresponding to one or more coverage areas;
wherein for at least one coverage area of the one or more coverage areas, the non-transitory computer readable medium is further configured to cause the UAV apparatus to store one or more second position location coordinates of target cells relative to a center of the at least one coverage area; and
wherein the non-transitory computer readable medium further comprises one or more instructions that are configured to cause the UAV apparatus to:
obtain one or more third position location coordinates and orientation angles of the UAV apparatus based on at least one of a gyroscope, an accelerometer and a position location sub-system; and
compute one or more pointing angles from the antenna fixture toward the target cells based at least in part on the second position location coordinates, the third position location coordinates, and the orientation angles of the UAV apparatus.
2. The UAV apparatus of claim 1 , where:
the antenna fixture is comprised of multiple antenna sub-apertures, where each antenna sub-aperture is configured to form at least one beam;
where each antenna sub-aperture is controlled by a corresponding actuator; and
the one or more instructions are further configured to cause the corresponding actuators to:
point each antenna sub-aperture toward a corresponding cell according to the one or more computed pointing angles.
3. The UAV apparatus of claim 1 , where:
the antenna fixture is comprised of multiple antenna elements spaced apart at substantially half wavelength distances;
an antenna sub-system comprises circuitry configured to phase the multiple antenna elements to form and point beams; and
where the one or more instructions are further configured to cause the antenna sub-system to point the beams according to the one or more computed pointing angles.
4. The UAV apparatus of claim 2 , where:
the antenna fixture comprises multiple antenna elements spaced apart at substantially half wavelength distances;
an antenna sub-system is configured to phase the multiple antenna elements to form and point beams.
5. The UAV apparatus of claim 1 , wherein the one or more instructions are further configured to cause the UAV apparatus to:
compute a required number of fixed beams to cover the at least one target coverage cell under a plurality of UAV altitudes and orientation angles; and
wherein the generated at least one beam comprises the computed number of fixed beams.
6. The UAV apparatus of claim 1 , where:
the antenna fixture is configured to receive a reference signal from a reference terminal associated with the at least one target coverage cell;
the antenna fixture is further configured to measure one or more signal quality measurements based on the reference signal received from the reference terminal; and
wherein the computed one or more pointing angles toward the reference terminal optimize the measured one or more signal quality measurements.
7. The UAV apparatus of claim 6 , wherein the one or more instructions are further configured to cause the UAV apparatus to:
determine one or more second position location coordinates of target cells in one or more rings of cells surrounding a central cell associated with the at least one target coverage cell.
8. The UAV apparatus of claim 7 , wherein the one or more instructions are further configured to cause the UAV apparatus to:
estimate an altitude of the UAV apparatus based at least in part on the one or more third position location coordinates of the UAV; and
compute the one or more pointing angles for each one of the at least one beam from the UAV apparatus based at least in part on the orientation angles, the estimated altitude, and the one or more second position location coordinates of target cells in the one or more rings of cells surrounding the central cell.
9. A method for forming antenna beams toward at least one target coverage cell, comprising:
determining a first location coordinate of an aerial platform;
determining an orientation of the aerial platform;
identifying one or more second location coordinates associated with the at least one target coverage cell;
wherein for at least one coverage area of the at least one target coverage cell, identifying one or more third location coordinates of surrounding cells relative to the at least one target coverage cell; and
computing one or more pointing angles toward the at least one target coverage cell and the surrounding cells based at least in part on the first location coordinate, the second location coordinates, the one or more third location coordinates, and the orientation of the aerial platform; and
generating at least one beam that covers the at least one target coverage cell and the surrounding cells based on the computed one or more pointing angles.
10. The method of claim 9 , wherein the determining the first location coordinate comprises determining one or more of a latitude coordinate, a longitude coordinate, and an altitude.
11. The method of claim 10 , wherein the identifying the one or more second location coordinates comprises receiving a message sent from a reference terminal associated with the at least one target coverage cell.
12. The method of claim 10 , wherein the one or more second location coordinates are determined based on a predefined placement.
13. A system for coordinating coverage provisioned from one or more aerial platforms for at least one target coverage cell and one or more surrounding cells relative to the at least one target coverage cell, comprising:
one or more aerial platforms configured to orbit near the at least one target coverage cell;
at least one reference cell associated with the at least one target coverage cell;
wherein the one or more aerial platforms are configured to receive a reference signal generated by the at least one reference cell and responsively determine at least one pointing angle that optimizes a signal quality metric of the received reference signal and generate one or more beams based on the at least one pointing angle; and
wherein the one or more aerial platforms are further configured to:
determine one or more first position location coordinates corresponding to the at least one target coverage cell;
determine one or more second position location coordinates of one or more surrounding cells relative to the at least one target coverage cell; and
obtain one or more third position location coordinates and orientation angles of the one or more aerial platforms based on at least one of a gyroscope, an accelerometer and a position location sub-system; and
wherein the computed at least one pointing angle is based on computing one or more pointing angles from the one or more aerial platforms toward the at least one target coverage cell and one or more surrounding cells based at least in part on the second position location coordinates, the third position location coordinates, and the orientation angles.
14. The system of claim 13 , wherein the one or more aerial platforms are configured to generate a beam which is narrower than an orbit one or more aerial platforms.
15. The system of claim 14 , wherein the one or more aerial platforms are configured to iteratively generate the beam within at least one sub-region of the orbit.
16. The system of claim 15 , wherein the iteratively generated beam within the at least one sub-region is generated for a duration of time which is substantially equal to a cruising orbit duration of the one or more aerial platforms.
17. The system of claim 13 , wherein the one or more aerial platforms are configured to generate a beam which completely encompasses an orbit of the one or more aerial platforms.
18. The system of claim 13 , wherein the at least one reference cell is further configured to transmit one or more location coordinates corresponding to one or more target cell coverage areas.