Method and system for orienting a phased array antenna
View Patent ↗A receive planar phased array antenna on a communications platform is used to estimate a pointing error of the antenna and to orient the antenna boresight towards the transmitter. A method for orienting the communications antenna includes: segmenting a receive phase array antenna into N sub-arrays with M-antenna elements in each sub-array; receiving, a known signal, by each of the M-antenna elements of at least four (4) of the N-sub-arrays; scanning in a direction of the known signal by applying a beam weight associated with each of the M elements in each of the at least 4-sub-arrays to obtain M-weighted signals for each of the at least 4-sub-arrays; combining the M-weighted signals for each of the at least 4-sub-arrays into signals A, B, C and D, respectively; generating an azimuth difference signal per a weighted sum of (A+B) and (C+D) and an elevation difference signal per a weighted sum of (A+C) and (B+D); computing the weights of the azimuth difference signal, such that the azimuth difference signals is driven to a zero signal; and computing the weights of the elevation difference signal, such that the elevation difference signal is driven to a zero signal.
1. A method for orienting a communications antenna, the method comprising:
segmenting a receive phase array antenna into N sub-arrays with M-antenna elements in each sub-array;
receiving, a known signal, by each of the M-antenna elements of at least four (4) of the N-sub-arrays;
scanning in a direction of the known signal by applying a beam weight associated with each of the M-antenna elements in each of the at least 4-sub-arrays to obtain M-weighted signals for each of the at least 4-sub-arrays;
combining the M-weighted signals for each of the at least 4-sub-arrays into signals A, B, C, and D, respectively;
generating an azimuth difference signal per a weighted sum of (A+B) and (C+D) and an elevation difference signal per a weighted sum of (A+C) and (B+D);
computing weights of the azimuth difference signal, such that the azimuth difference signal is driven to a zero signal; and
computing weights of the elevation difference signal, such that the elevation difference signal is driven to a zero signal,
wherein N is greater than or equal to four (4) and M is greater than or equal to one (1).
2. The method of claim 1 , wherein the known signal comprises a Digital Video Broadcasting-Carrier Identification Signal (DVB-CID).
3. The method of claim 1 , wherein the receive phase array antenna is disposed on a Geosynchronous Earth Orbit (GEO) satellite.
4. The method of claim 1 , wherein the receive phase array antenna is disposed on a Low Earth Orbit (LEO) satellite, a High Attitude Platform System (HAPS) or an aircraft.
5. The method of claim 1 , wherein the receive phase array antenna is used by a gateway, a stationary terminal, a mobile terminal, a ground-based terminal, or a terminal disposed in an aircraft.
6. The method of claim 1 , wherein the receive phase array antenna is the communications antenna.
7. The method of claim 1 , further comprising simultaneously generating a communications signal based on A+B+C+D.
8. The method of claim 1 , further comprising computing beam weights of each of the M-antenna elements of the N-sub-arrays based on the azimuth and elevation difference signals for the known signal.
9. The method of claim 1 , wherein N is greater than four (4),
and the combining further comprises combining the M-weighted signals for each of the N-sub-arrays into N-combined signals.
10. The method of claim 9 , further comprising simultaneously generating a communications signal transmitted from the direction of the known signal.
11. The method of claim 9 , further comprising:
applying N-combined signal weights to each of the N-combined signals, respectively; and
simultaneously generating a communications signal transmitted from a direction other than the direction of the known signal,
wherein the N-combined signal weights are based on the direction of the communications signal relative to the direction of the known signal.
12. The method of claim 11 , further comprising computing the N-combined signal weights for the N-combined signals based on the azimuth and elevation difference signals for the known signal.
13. A system to orient a communications antenna, the system comprising:
a receive phase array antenna comprising antenna elements segmented into N-sub-arrays with M-antenna elements in each sub-array, wherein a known signal is received by each of the M-antenna elements of at least four (4) of the N-sub-arrays;
an antenna subsystem to scan in a direction of the known signal by applying a beam weight associated with each of the M-antenna elements in each of the at least 4-sub-arrays to obtain M-weighted signals for each of the at least 4-sub-arrays;
a hybrid combiner network to combine the M-weighted signals for each of the at least 4-sub-arrays into signals A, B, C and D, respectively, and to generate an azimuth difference signal per a weighted sum of (A+B) and (C+D) and an elevation difference signal per a weighted sum of (A+C) and (B+D); and
a pointing system to compute weights of the azimuth difference signal, such that the azimuth difference signal is driven to a zero signal, and to compute weights of the elevation difference signal, such that the elevation difference signal is driven to a zero signal,
wherein N is greater than or equal to four (4) and M is greater than or equal to one (1).
14. The system of claim 13 , wherein the known signal comprises a Digital Video Broadcasting-Carrier Identification Signal (DVB-CID).
15. The system of claim 13 , wherein the receive phase array antenna is disposed on a Geosynchronous Earth Orbit (GEO) satellite.
16. The system of claim 13 , wherein the receive phase array antenna is disposed on a Low Earth Orbit (LEO) satellite, a High Attitude Platform System (HAPS) or an aircraft.
17. The system of claim 13 , wherein the receive phase array antenna is used by a gateway, a stationary terminal, a mobile terminal, a ground-based terminal, or a terminal disposed in an aircraft.
18. The system of claim 13 , wherein the receive phase array antenna is the communications antenna.
19. The system of claim 13 , wherein the hybrid combiner network is further configured to simultaneously generate a communications signal based on A+B+C+D.
20. The system of claim 13 , wherein the pointing system is further configured to compute beam weights of each of the M-antenna elements of the N-sub-arrays based on the azimuth and elevation difference signals for the known signal.
21. The system of claim 13 , wherein N is greater than four (4), and the hybrid combiner network is further configured to combine the M-weighted signals for each of the N-sub-arrays into N-combined signals.
22. The system of claim 21 , wherein the hybrid combiner network is further configured to simultaneously generate a communications signal transmitted from the direction of the known signal.
23. The system of claim 21 , wherein the hybrid combiner network is further configured to
apply N-combined signal weights to each of the N-combined signals, respectively,
simultaneously generate a communications signal transmitted from a direction other than the direction of the known signal, and
the N-combined signal weights are based on the direction of the communications signal relative to the direction of the known signal.
24. The system of claim 23 , wherein the pointing system is further configured to compute the N-combined signal weights for the N-combined signals based on the azimuth and elevation difference signals for the known signal.