GROUND-BASED SATELLITE ANTENNA POINTING SYSTEM

• US 20160365629A1
• Filed: 09/25/2014
• Published: 12/15/2016
• Est. Priority Date: 09/26/2013
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Orbital Sciences Corporation (Northrop Grumman Corporation)
• Inventors: Case, George, Yao, Huiwen
• Granted Patent: US 9,853,356 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: H01Q 1/1257 using the received signal strength
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 3/08 for varying two co-ordinates of the orientation
• CPC Class Codes: H04B 7/18519 Operations control, administration or maintenance
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

The present application includes systems and methods for determining pointing error of a satellite antenna. In one aspect a method for determining pointing error of a satellite antenna includes receiving, at a receiving station, a pointing error signal formed by the antenna and transmitted from a satellite, wherein the pointing error signal includes a first beacon (reference) signal and a modulated second beacon (error) signal. The receiving station may demodulate the received pointing error signal to recover the second beacon signal with respect to the first beacon signal, and based at least in part on the demodulated beacon signal, the receiving station may determine the pointing error of the satellite antenna.

Claims

1. A method for determining pointing error of a satellite antenna, the method comprising:

receiving, at a receiving station, a pointing error signal transmitted from a satellite, wherein the pointing error signal includes a first beacon signal and a modulated second beacon signal;

demodulating the received pointing error signal to recover the first beacon signal and the second beacon signal; and

determining a pointing error based at least in part on the first beacon signal and the second beacon signal.

2. The method of claim 1, further comprising:

determining a control signal based on the pointing error; and

transmitting the control signal to the satellite, wherein the control signal includes commands to modify an orientation of the satellite antenna.

3. The method of claim 1, wherein determining the pointing error based at least in part on the first beacon signal and the second beacon signal comprises:

comparing a magnitude of the second beacon signal with a magnitude of the first beacon signal; and

determining a phase of at least one of the first beacon signal and the second beacon signal.

4. The method of claim 3, wherein comparing the magnitude of the second beacon signal with the magnitude of the first beacon signal comprises taking a difference in magnitude of the first beacon signal and the second beacon signal.

5. The method of claim 3, wherein determining the pointing error based at least in part on the first beacon signal and the second beacon signal further comprises:

determining a direction of the pointing error based on the determined phase; and

determining a magnitude of the pointing error based on the comparison of the magnitude of the second beacon signal with the magnitude of the first beacon signal.

6. The method of claim 1, wherein at least one of the first beacon signal and the second beacon signal is configured to have substantially zero magnitude along a boresight axis of the satellite antenna and a substantially non-zero magnitude off of the boresight axis of the satellite antenna.

7. The method of claim 1, wherein the second beacon signal is modulated using one of:

phase modulation, frequency modulation, or amplitude modulation.

8. The method of claim 1, wherein the second beacon signal is modulated using a first phase angle and a second phase angle.

9. The method of claim 8, wherein the first phase angle is 0 degrees, and wherein the second phase angle is 180 degrees.

10. The method of claim 1, wherein the pointing error signal is generated by combining the first beacon signal and the modulated second beacon signal in a spatial domain.

11. A system for determining pointing error of a satellite antenna, the system comprising:

a receiver in communication with a satellite configured to receive a pointing error signal transmitted from the satellite, wherein the pointing error signal includes a first beacon signal and a modulated second beacon signal;

control circuitry configured to;

demodulate the received pointing error signal to recover the first beacon signal and the second beacon signal; and

determine a pointing error based at least in part on the first beacon signal and the second beacon signal.

12. The system of claim 11, wherein the control circuitry is further configured to:

determine a control signal based on the pointing error; and

transmit the control signal to the satellite, wherein the control signal includes commands to modify an orientation of the satellite antenna.

13. The system of claim 11, wherein the control circuitry is configured to determine the pointing error based at least in part on the first beacon signal and the second beacon signal by:

comparing a magnitude of the second beacon signal with a magnitude of the first beacon signal; and

determining a phase of at least one of the first beacon signal and the second beacon signal.

14. The system of claim 13, wherein the control circuitry is configured to compare the magnitude of the second beacon signal with the magnitude of the first beacon signal by taking a difference in magnitude of the first beacon signal and the second beacon signal.

15. The system of claim 13, wherein the control circuitry is further configured to determine the pointing error based at least in part on the first beacon signal and the second beacon signal by:

determining a direction of the pointing error based on the determined phase; and

determining a magnitude of the pointing error based on the comparison of the magnitude of the second beacon signal with the magnitude of the first beacon signal.

16. The system of claim 11, wherein at least one of the first beacon signal and the second beacon signal is configured to have substantially zero magnitude along a boresight axis of the satellite antenna and a substantially non-zero magnitude off of the boresight axis of the satellite antenna.

17. The system of claim 11, wherein the second beacon signal is modulated using one of:

phase modulation, frequency modulation, or amplitude modulation.

18. The system of claim 11, wherein the second beacon signal is modulated using a first phase angle and a second phase angle.

19. The system of claim 18, wherein the first phase angle is 0 degrees, and wherein the second phase angle is 180 degrees.

20. The system of claim 11, wherein the pointing error signal is generated by combining the first beacon signal and the modulated second beacon signal in a spatial domain.