Systems and methods for coherent signal fusion for time and frequency estimation

1. A signal processing system comprising:

a transmission architecture comprising a first transmitter configured to transmit a first signal and a second transmitter configured to transmit a second signal; and

a receiver architecture comprising:

at least one antenna configured to receive the first and second signals; and

a coherent signal fusion processing device communicatively coupled to said at least one antenna and configured to:

generate a broadband analog signal that contains the first and second signals;

digitize the broadband analog signal;

isolate a first signal of interest based on the first signal and a second signal of interest based on the second signal from the digitized signal;

estimate, relative to a reference template, at least one of a time difference of arrival and a frequency difference of arrival for the first signal of interest using a complex offset ambiguity function;

estimate, relative to the reference template, at least one of a time difference of arrival and a frequency difference of arrival for the second signal of interest using the complex offset ambiguity function; and

determine a location of at least one of the transmission architecture and the receiver architecture based on the estimated at least one of a time difference of arrival and a frequency difference of arrival for the first signal of interest and the estimated at least one of a time difference of arrival and a frequency difference of arrival for the second signal of interest.

2. A system in accordance with claim 1 , wherein said at least one antenna comprises at least two different antennas.

3. A system in accordance with claim 1 , wherein said at least one antenna comprises a single wideband antenna.

4. A system in accordance with claim 1 , wherein the reference template is stored on said coherent signal fusion processing device.

5. A system in accordance with claim 1 , wherein the reference template is a third signal that is received at a location separate from the first and second signals and transmitted to the receiver architecture.

6. A system in accordance with claim 1 , wherein said transmission architecture comprises:

a first antenna configured to transmit the first signal; and

a second antenna configured to transmit the second signal, wherein the second antenna is different from the first antenna.

7. A location system configured to determine a location of at least one of a transmission architecture and a receiver architecture, said location system comprising a coherent signal fusion processing device comprising:

a memory device; and

a processor communicatively coupled to said memory device, said processor configured to:

receive first and second signals;

generate a broadband analog signal that contains the first and second signals;

digitize the broadband analog signal;

isolate a first signal of interest and a second signal of interest from the digitized signal;

estimate, relative to a reference template, at least one of a time difference of arrival and a frequency difference of arrival for the first signal of interest using a complex offset ambiguity function;

estimate, relative to the reference template, at least one of a time difference of arrival and a frequency difference of arrival for the second signal of interest using a complex offset ambiguity function; and

output the estimated at least one of a time difference of arrival and a frequency difference of arrival for the first signal of interest and the estimated at least one of a time difference of arrival and a frequency difference of arrival for the second signal of interest.

8. A location system in accordance with claim 7 , wherein to receive first and second signals, said processor is configured to:

receive the first signal from a first antenna; and

receive the second signal from a second antenna different from the first antenna.

9. A location system in accordance with claim 7 , wherein to receive first and second signals, said processor is configured to receive both the first and second signals from a single wideband antenna.

10. A location system in accordance with claim 7 , wherein the reference template is stored on said memory device.

11. A location system in accordance with claim 7 , wherein the reference template is a third signal that is received at a location separate from the first and second signals transmitted to the receiver architecture.

12. A location system in accordance with claim 7 , wherein to isolate a first signal of interest and a second signal of interest from the digitized signal, said processor is configured to:

isolate the first signal of interest using a first constant delay filter; and

isolate the second signal of interest using a second constant delay filter.

13. A signal processing method comprising:

receiving first and second signals at a coherent signal fusion processing device;

generating, using the coherent signal fusion processing device, a broadband analog signal that contains the first and second signals;

digitizing, using the coherent signal fusion processing device, the broadband analog signal;

isolating, using the coherent signal fusion processing device, a first signal of interest and a second signal of interest from the digitized signal;

estimating, using the coherent signal fusion processing device, relative to a reference template, at least one of a time difference of arrival and a frequency difference of arrival for the first signal of interest using a complex offset ambiguity function;

estimating, using the coherent signal fusion processing device, relative to the reference template, at least one of a time difference of arrival and a frequency difference of arrival for the second signal of interest using a complex offset ambiguity function; and

outputting the estimated at least one of a time difference of arrival and a frequency difference of arrival for the first signal of interest and the estimated at least one of a time difference of arrival and a frequency difference of arrival for the second signal of interest.

14. A method in accordance with claim 13 , wherein receiving first and second signals comprises:

receiving the first signal from a first antenna; and

receiving the second signal from a second antenna different from the first antenna.

15. A method in accordance with claim 13 , wherein receiving first and second signals comprises receiving both the first and second signals from a single wideband antenna.

16. A method in accordance with claim 13 , wherein the reference template is stored on the coherent signal fusion processing device.

17. A method in accordance with claim 13 , wherein the reference template is a third signal received at the coherent signal fusion processing device that is separate from the first and second signals.