System and method for measuring phase and power variance

• US 20080012756A1
• Filed: 07/12/2006
• Published: 01/17/2008
• Est. Priority Date: 07/12/2006
• Status: Active Grant

• Current Assignee: Enterprise Electronics
• Original Assignee: Enterprise Electronics
• Inventors: Alford, James Larry, Helvin, James Rogers, Nelson, Dean A., Stagliano, James J.
• Granted Patent: US 7,683,828 B2
• Time in Patent Office: Days
• US Class Current: 342/26R
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/95 for meteorological use
• CPC Class Codes: G01S 7/025 involving the transmission of linearly polarised waves
• CPC Class Codes: G01S 7/03 Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
• CPC Class Codes: G01S 7/2886 using I/Q processing
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A device and method for measuring phase and power shifts in a simultaneous dual polarization radar system comprises an access port, a quadrature mixer, and a power detector. The access port is configured to couple to the simultaneous dual polarization radar system near the antenna of the simultaneous dual polarization radar system. The quadrature mixer is configured to mix a first signal from a first polarization and a second signal from a second polarization. The first signal and the second signal are sampled through the access port. The first power detector is configured to measure the power level of the first signal.

Claims

1. A measurement device for measuring phase and power shifts in a simultaneous dual polarization radar system, comprising:

a. an access port configured to couple to said simultaneous dual polarization radar system near the antenna of said simultaneous dual polarization radar system;

b. a quadrature mixer configured to mix a first signal from a first polarization and a second signal from a second polarization, said first signal and said second signal sampled through said access port; and

c. a first power detector configured to measure the power level of said first signal.

2. The measurement device of claim 1, further comprising a second power detector configured to measure the power of said second signal.

3. The measurement device of claim 2, wherein said first power detector and said second power detector are diodes.

4. The measurement device of claim 3, wherein said first power detector and said second power detector are Shottky diodes.

5. The measurement device of claim 1 further comprising a first attenuator and a second attenuator configured to attenuate said first signal and said second signal to a level set by said quadrature mixer.

6. The measurement device of claim 1, further comprising a first signal splitter configured to split said first signal into two half signals;

said half signals being passed to said quadrature mixer and said first power detector.

7. The measurement device of claim 1, further comprising an A-D converter configured to receive the measurement of the power of said first signal from said first power detector and further configured to receive in-phase and quadrature signals from said quadrature mixer.

8. The measurement device of claim 7, wherein said A-D converter is further configured to receive said in-phase and quadrature signals in video format.

9. The measurement device of claim 8, wherein said A-D converter outputs a digital representation of said in-phase and quadrature signals and a digital representation of said power signal.

10. The measurement device of claim 9, wherein said A-D converter is further configured to calculate the phase shift and the power shift of said first signal and said second signal.

11. The measurement device of claim 10, further comprising a second power detector configured to measure the power of said second signal.

12. The measurement device of claim 11, wherein said A-D converter is further configured to calculate a bias shift in said phase shift based upon a relative power shift between said first signal and said second signal.

13. The measurement device of claim 1, wherein said access port is further configured to sample a received signal from said antenna.

14. A method of measuring a phase shift and a power shift in a transmitted signal in a simultaneous dual polarization radar system, comprising the steps of:

a. receiving a sample of a first signal and a sample of a second signal near an antenna of said simultaneous dual polarization radar system;

b. receiving an idealized first signal and an idealized second signal;

c. comparing said sample of said first signal to said idealized first signal;

comparing said sample of said second signal to said idealized second signal; and

,

d. calculating a phase shift between said sample of said first signal and said sample of said second signal and a power shift between said sample of said first signal and said sample of said second signal.

15. The method of claim 14, further comprising the step of attenuating said first signal and said second signal to a level set by a quadrature mixer.

16. The method of claim 15, further comprising the step of splitting said first signal into two half signals.

17. The method of claim 16, further comprising the step of measuring the power of said first signal through one of said two half signals.

18. The method of claim 17, further comprising the step of receiving the measurement of the power of said first signal from said first power detector and further configured to receive in-phase and quadrature signals from said quadrature mixer.

19. The method of claim 18, further comprising the step of receiving said in-phase and quadrature signals in video format.

20. The method of claim 19, further comprising the step of outputting a digital representation of said in-phase and quadrature signals and a digital representation of said power signal.

21. The method of claim 20, further comprising the step of calculating the phase shift and the power shift of said first signal and said second signal using said in-phase and quadrature signals and said power signal.

22. The method of claim 21, further comprising the step of calculating a bias shift in said phase shift based upon a relative power shift between said first signal and said second signal.

23. The method of claim 14, further comprising the step of sampling a received signal from said antenna.

24. The method of claim 14, further comprising the step of defining an antenna location when said sampling step occurs.

25. The method of claim 24, further comprising the step of recording said antenna location, said phase shift and said power shift.

26. The method of claim 25, further comprising the step of creating a histogram of said phase shift and said power shift as a function of said antenna location.

27. An apparatus for measuring the phase shift and power shift of a transmitted signal in a simultaneous dual polarization radar system, comprising:

a. means for sampling a first signal from a first polarization and a second signal from a second polarization, said sampling means co-located with an antenna of said simultaneous dual polarization radar system;

b. means for mixing said first signal from said first polarization and said second signal from said second polarization;

c. means for measuring the power level of said first signal; and

d. means for referencing an idealized first signal and an idealized second signal such that a phase shift between said sample of said first signal and referencing sample of said second signal and a power shift between said sample of said first signal and said sample of said second signal is calculated from said sample of said first signal, said sample of said second signal, said idealized first signal and said idealized second signal.

28. The device of claim 27, further comprising a quadrature mixer configured to mix said sample of said first signal and said sample of said second signal;

and a first power detector configured to measure the power level of said sample of said first signal.

29. The device of claim 28, further comprising an attenuator configured to attenuate said sample of said first signal and said sample of said second signal to a level set by said quadrature mixer.

30. The device of claim 29, further comprising a splitter configured to split said first signal into two half signals.

31. The device of claim 30, wherein said first power detector is configured to detect the power of said sample of said first signal through one of said two half signals.

32. The device of claim 31, further comprising an A-D converter configured to receive the measurement of the power of said first signal from said first power detector and further configured to receive in-phase and quadrature signals from said quadrature mixer.

33. The device of claim 32, wherein said A-D converter is further configured to receive said in-phase signal and said quadrature signal in video format.

34. The device of claim 33, wherein said A-D converter is configured to output a digital representation of said in-phase signal and said quadrature signal and a digital representation of said power signal.

35. The device of claim 34, wherein said A-D converter is configured to calculate the phase shift and the power shift of said sample of said first signal and said sample of said second signal using said in-phase signal, said quadrature signal and said power signal.

36. The device of claim 35, wherein said A-D converter is configured to calculate a bias shift in said phase shift based upon a relative power shift between said sample of said first signal and said sample of said second signal.

37. The device of claim 27, wherein said sample from said first signal and said sample from said second signal are sampled from a received signal from said antenna.

38. The device of claim 27, further comprising an antenna location recording the azimuth angle and elevation angle of said antenna when said sampling step occurs.

39. The method of claim 38, further comprising a histogram of said phase shift and said power shift as a function of said antenna location.