Self Focusing Distributed Communications Array

• US 20100222005A1
• Filed: 02/27/2009
• Published: 09/02/2010
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Jacomb-Hood, Anthony W.
• Granted Patent: US 8,090,336 B2
• Time in Patent Office: Days
• US Class Current: 455/66.100
• CPC Class Codes: H04B 7/0894 using different delays between antennas

Abstract

A method of processing signals received and transmitted between a satellite and sub-arrays of an antenna array. The satellite emits an analog signal received by the sub-arrays, each sub-array in turn produces a corresponding output. The array'"'"'s total output is approximated by designating one of the sub-array'"'"'s output as a reference output, and digitally forming a series of beams that consist of the reference output and permutations of the other sub-array outputs with either no time delay or with a time delay applied. A high power beam from the series is selected for cross correlation with each sub-array output to determine the signal'"'"'s relative arrival time at each sub-array. Each sub-array output is time delayed based on the signal arrival time at that sub-array. The time delayed outputs are combined to form a high gain beam.

Claims

1. A method of communicating between a remote transmitting station and a receive antenna having at least two sub-arrays, the method comprising:

a. receiving a signal transmitted by the remote transmitting station with the at least two of the antenna sub-arrays, so that each of the at least two sub-arrays forms an output signal corresponding to the received signal;

b. designating the output of one of the at least two sub-arrays as a reference output signal;

c. forming a collection of composite output signals by combining the reference output signal with permutations of output signals from the other of the at least two sub-arrays and their output signals having an added time delay;

d. selecting a composite output signal from the collection;

e. calculating time offsets between the selected composite output signal and the at least two sub-array output signals;

f. selecting the output signal from the sub-array having received the signal last and adding a time adjustment to the output signals associated with other sub-arrays so that the output signals from each sub-array are synchronized; and

g. combining the time adjusted output signals to create an output signal.

2. The method of claim 1, further comprising cross correlating the selected composite output signal with the at least two sub-array output signals to calculate the time offsets of step (e).

3. The method of claim 1, wherein the composite output signal selected in step (d) is the composite output signal having a high power.

4. The method of claim 1, further comprising steering the at least two sub-arrays towards the remote transmitting station.

5. The method of claim 1, wherein the remote transmitting station is a satellite.

6. The method of claim 1, further comprising maintaining a signal lock by performing steps (e)-(g) within a discrete time period so that the relative distance of the sub-arrays with respect to the remote transmitting station is substantially unchanged, and forming the composite output signal using the relative time delays calculated in step (f) of the prior discrete time period.

7. The method of claim 1, further comprising receiving a beacon signal from the remote transmitting station.

8. The method of claim 7, further comprising receiving signal content and performing steps (f)-(g) using the previous calculated time offset as a starting point.

9. The method of claim 1, further comprising repeating steps (a)-(g) in a time period up to about 100 μ

s.

10. The method of claim 1, further comprising transmitting a signal with the at least two of the antenna sub-arrays and adjusting the relative transmit times of each sub-array with the time adjustments.

11. The method of claim 1, further comprising providing the sub-arrays on a vehicle'"'"'s outer surface so that the remote transmitting station signal arrival time at a first sub-array is different from the remote transmitting station signal arrival time at a second sub-array.

12. A method of communicating between a remote receiving station and a transmit antenna having at least two sub-arrays, the method comprising:

a. receiving a signal transmitted by the at least two of the antenna sub-arrays, so that the receiving station forms an output signal corresponding to the signal transmitted by each of the antenna sub-arrays;

b. designating the signal received from one of the at least two sub-arrays as a reference output signal;

c. forming a collection of composite output signals by combining the reference output signal with permutations of output signals from the other of the at least two sub-arrays and their output signals having an added time delay;

d. selecting a composite output signal from the collection;

e. calculating time offsets between the signals by comparing arrival times of the selected composite output signal with the at least two sub-array output signals;

f. selecting the received signal with the highest time delay and adding a time adjustment to the output signals associated with other sub-arrays so that the output signals from each sub-array is synchronized; and

g. combining the time adjusted output signals to create an output signal.

13. The method of claim 12, further comprising cross correlating the selected composite output signal with the at least two sub-array output signals to calculate the time offsets of step (e).

14. The method of claim 12, further comprising transponding the signal from the remote transmitting station through a satellite to the receive antenna.

15. A method of signal communications comprising:

a. sending signals from at least two antenna sub-arrays of an antenna;

b. designating the sent signal of one of the at least two sub-arrays as a reference sent signal;

c. forming a collection of composite sent signals by combining the reference sent signal with permutations of sent signals from the other of the at least two sub-arrays and their sent signals having an added time delay;

d. selecting a composite sent signal from the collection;

e. calculating time offsets between the sent signals by cross correlating the selected composite output signal with the at least two sub-array output signals;

f. synchronizing the sent signals based on the calculated time offsets; and

g. combining the time adjusted output signals to create an output signal.

16. The method of claim 15, further comprising receiving the sent signals with a satellite and transponding the signals to another location.

17. The method of claim 15, wherein the composite signal selected in step (d) is the composite signal having a high power.

18. The method of claim 16, further comprising receiving a beacon signal from the satellite at the other location.

19. The method of claim 15, further comprising receiving signal content at the other location and performing steps (f)-(g) using the previous calculated time offset as a starting point.

20. A method of processing signals handled by an antenna having at least two sub-arrays, the method comprising:

a. receiving output signals from at least two antenna sub-arrays of an antenna;

b. designating the received signal of one of the at least two sub-arrays as a reference signal;

c. forming a collection of composite signals by combining the reference sent signal with permutations of signals from the other of the at least two sub-arrays and their signals having an added time delay;

d. selecting a composite signal from the collection;

e. calculating time offsets between the signals by cross correlating the selected composite signal with the other received signals;

f. synchronizing the received signals based on the calculated time offsets; and

g. combining the time adjusted output signals to create a coherent signal.

21. The method of claim 20, further comprising receiving a signal from a satellite with the at least two sub-arrays and forming the output signals of step (a) from the at least two sub-arrays.

22. The method of claim 20, further comprising transmitting signals from the at least two sub-arrays to a satellite and transponding the signals from the satellite to form the output signals of step (a).

23. A method of processing signals handled by an antenna having at least two sub-arrays, the method comprising:

a. receiving output signals from at least two antenna sub-arrays of an antenna;

b. designating the received signal of one of the at least two sub-arrays as a reference signal;

c. forming a collection of composite signals by combining the reference sent signal with permutations of signals from the other of the at least two sub-arrays and their signals having an added phase shift;

d. selecting a composite signal from the collection;

e. calculating time offsets between the signals by cross correlating the selected composite signal with the other received signals;

f. synchronizing the received signals based on the calculated time offsets; and

g. combining the time adjusted output signals to create a coherent signal.