Methods for determining a reference signal at any location along a transmission media

• US 8,170,088 B2
• Filed: 11/19/2008
• Issued: 05/01/2012
• Est. Priority Date: 11/19/2008
• Status: Active Grant

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Martin, G. Patrick
• Primary Examiner(s): Torres, Juan A
• Application Number:
  US12/273,797
• Publication Number:
  US 20100124302A1
• Time in Patent Office: 1,259 Days
• Field of Search: 375/224
• US Class Current: 375/224
• CPC Class Codes: G06F 1/10 Distribution of clock signals , e.g. skew
• CPC Class Codes: H04B 7/02 Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas RAKE receivers H04B1/7115

Abstract

Methods (200, 300) for determining a reference signal (V_ref). The methods involve (202, 204, 302, 304) sensing at a first location along the transmission media (108, 502) a first signal (V_f) propagated thereover in a forward direction and a second signal (V_r) propagated thereover in a reverse direction opposed from the forward direction. The second signal being a reflected version of the first signal. A sum signal (S) is determined (206, 306) by adding the first and second signals together. A difference signal (D) is determined (208, 308) by subtracting the second signal from the first signal. Thereafter, a first exponentiation signal (E_S) is determined (210, 310) using S. A second exponentiation signal (E_D) is determined (212, 312) using D. The first exponentiation signal is subtracted (214, 314) from the second exponentiation signal to obtain a reference signal (V_ref). V_ref can be determined at any location along the transmission media. V_ref can be used to control the phases and/or amplitudes of communication signals.

Claims

1. A method for utilizing at least one reference signal in an antenna system, said reference signal determined at any location along a transmission media, comprising the steps of:

sensing at a first location along the transmission media a first signal propagated over the transmission media in a forward direction and a second signal propagated over the transmission media in a reverse direction opposed from the forward direction, the second signal being a reflected version of the first signal;

adjusting a gain of at least one of the first and second signals so that the first and second signals have equal arbitrarily defined amplitudes;

determining a first sum signal by adding the first and second signals together and a first difference signal by subtracting the second signal from the first signal;

determining a first exponentiation signal by raising the first sum signal to a second power and a second exponentiation signal by raising the first difference signal to the second power;

determining a first reference signal by subtracting the first exponentiation signal from the second exponentiation signal;

performing closed loop operations using the first reference signal to determine at least one weight useful for controlling beam steering of the antenna system; and

controlling beam steering of the antenna system by using the weight to modify a transmit signal, whereby beam steering errors caused by an error in a phase of the transmit signal are counteracted.

2. The method according to claim 1, further comprising increasing or decreasing a first frequency of the first reference signal by a certain amount.

3. The method according to claim 1, wherein the first reference signal has a first frequency different than a second frequency of the first signal.

4. The method according to claim 3, further comprising the step of processing the first reference signal to obtain an adjusted reference signal with a third frequency equal to the second frequency of the first signal.

5. The method according to claim 1, further comprising the steps of:

sensing at a second location different from the first location along the transmission media the first and second signal; and

determining a second reference signal using the first and second signals sensed at the second location;

wherein the second reference signal has the same phase as the first reference signal.

6. The method according to claim 5, wherein the step of determining a second reference signal comprises

determining a second sum signal by adding the first and second signals sensed at the second location together and a second difference signal by subtracting the second signal sensed at the second location from the first signal sensed at the second location,

determining a third exponentiation signal by raising the second sum signal to the second power and a fourth exponentiation signal by raising the second difference signal to the second power, and

determining the second reference signal by subtracting the third exponentiation signal from the fourth exponentiation signal.

7. The method according to claim 5, wherein the closed loop operations further comprise using the second reference signal to determine the weight.

8. The method according to claim 5, wherein the closed loop operations further comprise comparing a phase of the transmit signal with a phase of the first reference signal to determine a phase offset.

9. The method according to claim 1, further comprising communicating the first signal from a signal source to a reflective termination over the transmission media, and communicating said second signal from the reflective termination to a non-reflective termination over the transmission media, said reflective termination moving relative signal source.

10. A method for utilizing at least one reference signal in an antenna system, said reference signal determined at any location along a transmission media, comprising the steps of:

sensing at a first location along the transmission media a first signal propagated over the transmission media in a forward direction and a second signal propagated over the transmission media in a reverse direction opposed from the forward direction, the second signal being a reflected version of the first signal;

sensing at a second location different from the first location along the transmission media the first and second signals;

adjusting a gain of at least one of the first and second signals so that the first and second signals have equal arbitrarily defined amplitudes;

determining a first sum signal by adding the first and second signals sensed at the first location together and a first difference signal by subtracting the second signal sensed at the first location from the first signal sensed at the first location;

determining a first exponentiation signal by raising the first sum signal to a second power and a second exponentiation signal by raising the first difference signal to the second power;

determining a first reference signal by subtracting the first exponentiation signal from the second exponentiation signal;

determining a second reference signal using the first and second signals sensed at the second location;

performing closed loop operations using the first reference signal and the second reference signal to determine at least one weight useful for controlling beam steering of the antenna system; and

controlling beam steering of the antenna system by using the weight to modify a transmit signal, whereby beam steering errors caused by an error in a phase of the transmit signal are counteracted;

wherein the second reference signal has the same phase as the first reference signal.

11. The method according to claim 10, wherein the first reference signal has a first frequency equal to a second frequency of the first signal.

12. The method according to claim 10, wherein the first reference signal has a first frequency different than a second frequency of the first signal.

13. The method according to claim 12, further comprising the step of processing the first reference signal to obtain an adjusted reference signal with a third frequency equal to the second frequency of the first signal.

14. The method according to claim 10, wherein the step of determining the second reference signal comprises

determining a second sum signal by adding the first and second signals sensed at the second location together and a second difference signal by subtracting the second signal sensed at the second location from the first signal sensed at the second location,

determining a third exponentiation signal by raising the second sum signal to the second power and a fourth exponentiation signal by raising the second difference signal to the second power, and

subtracting the third exponentiation signal from the fourth exponentiation signal to obtain the second reference signal.

15. The method according to claim 14, further comprises the step of processing the second reference signal to obtain an adjusted reference signal with a first frequency equal to a second frequency of the first signal.

16. A method for utilizing at least one reference signal in an antenna system, said reference signal determined at any location along a transmission media, comprising the steps of:

sensing at a first location along the transmission media a first signal propagated over the transmission media in a forward direction and a second signal propagated over the transmission media in a reverse direction opposed from the forward direction, the second signal being a reflected version of the first signal;

adjusting a gain of at least one of the first and second signals so that the first and second signals have equal arbitrarily defined amplitudes;

determining a first sum signal by adding the first and second signals together and a first difference signal by subtracting the second signal from the first signal;

determining a first exponentiation signal by raising the first sum signal to a second power and a second exponentiation signal by raising the first difference signal to the second power;

determining a first reference signal by subtracting the first exponentiation signal from the second exponentiation signal;

performing closed loop operations using the first reference signal to determine at least one weight useful for controlling beam steering of the antenna system; and

using the weight to adjust the phase or amplitude of a communication signal so as to counteract beam steering errors caused by an error in a phase of the communication signal.

17. The method according to claim 16, wherein the first reference signal has a first frequency equal to a second frequency of the first signal.

18. The method according to claim 16, wherein the first reference signal has a first frequency different than a second frequency of the first signal.

19. The method according to claim 18, further comprising the step of processing the first reference signal to obtain an adjusted reference signal with a third frequency equal to the second frequency of the first signal.

20. The method according to claim 18, further comprising the steps of:

sensing at a second location different from the first location along the transmission media the first and second signal; and

determining a second reference signal using the first and second signals sensed at the second location;

wherein the second reference signal has the same phase as the first reference signal.