System and method for measuring phase and power variance

• US 7,683,828 B2
• Filed: 07/12/2006
• Issued: 03/23/2010
• Est. Priority Date: 07/12/2006
• Status: Expired due to Fees

• Current Assignee: Enterprise Electronics
• Original Assignee: Enterprise Electronics
• Inventors: Alford, James Larry, Helvin, James Rogers, Stagliano, James J. Jr., Nelson, Dean A.
• Primary Examiner(s): Gregory; Bernarr E
• Application Number:
  US11/485,017
• Publication Number:
  US 20080012756A1
• Time in Patent Office: 1,350 Days
• Field of Search: 342 26 R- 26 D, 342/59, 342/89, 342/165, 342173-175, 342188-197, 342361-366, 342/118, 342/124, 342/147, 342/149, 342/153, 342/159, 342/176, 342/179, 702/189, 329/315, 329/316
• US Class Current: 342/173
• 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 variance and power levels in a simultaneous dual polarization radar system having two transmission conduits for transmitting radio frequency signals to an antenna for further propagation of said radio frequency signals into space, comprising:

a. a sampling port coupled to each said transmission conduit;

b. a quadrature mixer configured to mix a first signal from one said transmission conduit and a second signal from said other transmission conduit to measure phase variance between said first and second signals; and

,

c. at least one power detector configured to measure power levels in at least one of said signals through said sampling ports.

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

3. The measurement device of claim 2, wherein said power detectors comprise detector diodes.

4. The measurement device of claim 2, further comprising a first signal splitter configured to split said first signal into two portions;

wherein one signal portion is input into said quadrature mixer and said other portion is measured by one of said power detectors.

5. The measurement device of claim 4, further comprising a second signal splitter configured to split said second signal into two portions, wherein one signal portion is input into said quadrature mixer and said other portion is measured by said second power detector.

6. The measurement device of claim 1 further comprising a first attenuator and a second attenuator, each attenuator configured to attenuate each said first and second signal to a level compatible with the specifications of said quadrature mixer.

7. The measurement device of claim 1, further comprising an A-D converter configured to digitize measurement signals from said at least one power detector and digitize in-phase and quadrature output 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, further comprising a micro-processing circuit coupled to said A-D converter for receiving said digitized signals from said quadrature mixer and processing said same, and for receiving said digitized signals from said at least one power detector.

10. The measurement device of claim 9, further comprising a second power detector configured to measure power levels in said other signal.

11. The measurement device of claim 10, wherein said A-D converter is further configured to receive measurements from said second power detector and calculate the phase shift and the power shift of said first signal and 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 each said sampling port are positioned adjacent to said radar antennae and configured to sample received signals from said antenna, and wherein said quadrature mixer is further configured to mix transmitted signals from said transmission conduits with said sampling port received signal samples.

14. The measurement device of claim 1 further including a local oscillator and wherein said quadrature mixer is further configured to receive a reference signal from said local oscillator and wherein said local oscillator has a frequency that enables said quadrature mixer to measure phase variances between said first and second signal.

15. In a simultaneous dual polarization radar system having two transmission conduits for transmitting radio frequency signals to an antenna for further propagation of said signals into space and at least one sampling port coupled to each of said conduits, a method of measuring a phase shift and a power shift in said radio signals comprising the steps of:

a. receiving a sample of a first signal from one said transmission conduit and a sample of a second signal from said other transmission conduit adjacent to said antenna of said simultaneous dual polarization radar system;

b. receiving a first reference signal and a second reference signal;

c. comparing said sample of said first signal to said first reference signal and comparing said sample of said second signal to said second reference 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.

16. The method of claim 15, wherein said step of receiving samples of first and second signals comprises sampling said signals from said sampling ports and wherein said method further comprises the step of attenuating said first signal and said second signal to a level compatible with a quadrature mixer.

17. The method of claim 16, further comprising the step of splitting said first signal into two portions.

18. The method of claim 17, further comprising the step of measuring the power of said first signal through one of said signal portions.

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

20. The method of claim 19, further comprising the step of measuring the power of said second signal.

21. The method of claim 20, further comprising the step of splitting said second signal into two portions and measuring the power of said second signal through one of said portions;

and wherein said first signal and said second signal have the same phase.

22. 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 measurements of said first and second signals.

23. The method of claim 22, 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.

24. The method of claim 15, further comprising the step of sampling a received signal from said antenna, and wherein said first sample of said first signal and said sample of said received signal are compared to one another through a quadrature mixer.

25. The method of claim 15, further comprising the step of defining an antenna location when said sampling step occurs.

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

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

28. An apparatus for measuring phase variance and power levels in a simultaneous dual polarization radar system having two transmission conduits for transmitting radio frequency signals to an antenna for further propagation of said radio frequency signals into space, comprising:

a. means for sampling radio signals from said radar transmission conduits;

b. means for mixing said transmission samples;

c. means for measuring power levels in at least one of said signals; and

,

d. means for comparing a reference signal to each said transmission signal to measure phase variance between the two, and means for comparing power in each transmission signal to a reference signal.

29. The device of claim 28, wherein said mixing means comprises a quadrature mixer, and wherein said comparing means comprises a power detector configured to measure the power level of said samples of said signals.

30. The device of claim 29, further comprising a second power detector configured to measure power levels in said radio frequency signals.

31. The device of claim 30, further comprising a signal splitter configured to split one of said signals into two portions and wherein said second power detector is configured to measure power levels in one of said signals in one of said portions.

32. The device of claim 31, further comprising an A-D converter configured to receive measurements of the power of one of said signals from said second power detector and is further configured to calculate phase shifts and the power shifts of said samples of said signals based upon in-phase signal, said quadrature signal parameters.

33. The device of claim 32, wherein each said sampling means are positioned adjacent to said radar antennae and configured to sample received signals from said antenna, and wherein said mixer means is further configured to mix transmitted signals from said transmission conduits with said sampling means received signal samples.

34. The method of claim 33, further comprising means for producing a histogram of said phase shift and said power shift as a function of said antenna location.