Adaptive antenna tracking of moving transmitters and receivers

• US 9,952,307 B2
• Filed: 08/31/2015
• Issued: 04/24/2018
• Est. Priority Date: 08/31/2015
• Status: Active Grant

• Current Assignee: Meta Platforms, Inc. (f/k/a Facebook, Inc.)
• Original Assignee: Meta Platforms, Inc. (f/k/a Facebook, Inc.)
• Inventors: Gan, Hong
• Primary Examiner(s): Liu, Harry K
• Application Number:
  US14/840,430
• Publication Number:
  US 20170059688A1
• Time in Patent Office: 967 Days
• Field of Search: 342372
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled
• CPC Class Codes: G01S 3/325 Automatic tracking systems
• CPC Class Codes: H01Q 21/205 providing an omnidirectional coverage turnstile aerials H01Q21/26
• CPC Class Codes: H01Q 3/04 for varying one co-ordinate of the orientation
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H01Q 3/28 varying the amplitude
• CPC Class Codes: H01Q 3/34 by electrical means active lenses or reflecting arrays H01Q3/46
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service

Abstract

A combined electro-mechanical adaptive antenna tracking system for wireless communication between transmitters and receivers moving relative to each other is described. This system enables one or more antenna transceivers on a moving object, such as a high altitude unmanned aerial vehicle (HALE UAV), to simultaneously track one or more separate antenna transceivers on the ground, such as multiple customer premises equipment. The antennas on the moving object are constructed with multiple-subsection phased arrays or may have multiple horns on one rotation axis. Adaptive tracking control logic is applied to synchronize electrical switch and/or mechanical rotation and electrical beamforming for the moving transceivers to track multiple ground transceivers. In one advantageous aspect, an off-the-shelf horn antenna can be used and rotated around only one axis, thereby eliminating the need for expensive two dimensional movement actuators such as gimbals and the need for tracking multiple ground based receivers.

Claims

1. A method of tracking relative movement between one or more transmitters and one or more receivers in a radio frequency communication system in which the relative movement between the one or more transmitters and the one or more receivers is within a range of angle of an aerial vehicle housing one of the one or more transmitters or the one or more receivers, comprising:

dividing the range into multiple sectors that collectively span an entirety of the range;

operating an antenna steering subsystem that uses a single axis rotation mechanism to cause an antenna system to track the relative movement between the one or more transmitters and the one or more receivers;

using electrical beamforming to refine tracking of the relative movement while the antenna system is in a fixed mechanical position;

receiving signal transmissions from the one or more transmitters; and

analyzing the received signal transmissions to generate a feedback signal to control operation of the antenna steering subsystem and the electrical beamforming.

2. The method of claim 1, wherein the receiving signal transmissions includes receiving signal transmissions using a horn antenna.

3. The method of claim 2, wherein the single axis rotation mechanism rotates the antenna system along one direction only.

4. The method of claim 1, wherein the analyzing the received signal transmissions includes:

computing a received signal strength indicator that estimates power level of a received reference signal.

5. The method of claim 1, wherein the analyzing the received signal transmissions includes:

combing angles of arrival of the received signal transmissions at multiple subsections antenna and/or antenna arrays.

6. The method of claim 1, wherein the receiving the signal transmissions from the one or more transmitters includes receiving the signal transmissions from the aerial vehicle and the generating the feedback signal includes generating the feedback signal to correct for the transmitter range for a 360-degree movement of the aerial vehicle with respect to a fixed position of the one or more receivers.

7. The method of claim 1, wherein the operating the antenna steering subsystem continually adjusts an aperture of the antenna system to maximize electrical gain of the received signal transmissions.

8. The method of claim 1, wherein the using the electrical beamforming includes:

adjusting a phase component and a gain component of the antenna system.

9. The method of claim 1, wherein the operating the antenna steering subsystem includes:

operating the antenna steering subsystem to steer the antenna system to one of multiple antenna positions corresponding to the multiple sectors.

10. The method of claim 9, wherein the antenna steering subsystem rotates a reference plane of the electrical beamforming based on an angle of the aerial vehicle.

11. The method of claim 1, wherein the operating the antenna steering subsystem includes:

operating the antenna steering subsystem to concurrently track multiple communication links.

12. The method of claim 1, further comprising:

performing the electrical beamforming using an electrical antenna switch to combine multiple signals received by the antenna system.

13. An antenna system of a receiver, comprising:

an antenna array having multiple subsections, wherein at least some subsections are movable in one dimension;

an electrical switch matrix that combines signals received at the multiple subsections;

a mechanical system coupled to the antenna array to move the antenna array;

an electrical subsystem configured to perform beamforming to steer a radio frequency beam emitted by the antenna array in a direction of a transmitter,

wherein a relative position of the transmitter with respect to the antenna system moves in a range comprising a 360-degree circle in a plane, wherein the mechanical system covers the range at a first level of granularity and the electrical subsystem performs beamforming at each of the first level of granularity.

14. The system of claim 13, wherein the antenna system includes at least one of a horn antenna and a patch antenna.

15. The system of claim 14, wherein the mechanical system moves the antenna system along one direction only.

16. The system of claim 13, wherein the electrical switch matrix combines the signals received at the multiple subsections by using at least some of:

a digital beamforming technique, a radio frequency switch, an intermediate frequency switch and a mechanical switch.

17. The system of claim 13, wherein the electrical subsystem analyzes the received signal transmissions from the transmitter by:

computing a received signal strength indicator that estimates power level of a received reference signal and phases of the received reference signal at the multiple subsections.

18. The system of claim 13, wherein the electrical subsystem analyzes the received signal transmissions from the transmitter by:

receiving information about condition of a link via which the signals are received, including one or more of;

a global positioning system signal measurement, an inertial navigation system measurement, a link signal measurement, and a beam interference measurement.

19. The system of claim 13, wherein the transmitter is housed on an aerial vehicle and the range includes a 360-degree movement of the aerial vehicle with respect to a fixed position of the receiver.

20. The system of claim 13, wherein the mechanical system and the electrical subsystem continually adjust an aperture of the antenna array to maximize an electrical gain of the received signals.

21. The system of claim 13, wherein the electrical subsystem performs electrical beamforming by:

adjusting a phase component and a gain component of the antenna system.

22. The system of claim 13, wherein the mechanical system steers the antenna array to one of multiple positions corresponding to the plurality of subsections.

23. The system of claim 22, wherein the mechanical system rotates a reference plane of the electrical beamforming based on the attitude of the aerial vehicle.