Simultaneous dual polarization radar system

• US 6,859,163 B2
• Filed: 03/21/2003
• Issued: 02/22/2005
• Est. Priority Date: 09/20/2002
• Status: Expired due to Term

• Current Assignee: Enterprise Electronics
• Original Assignee: DRS Weather Systems, Inc. (The Weather Company)
• Inventors: Alford, James Larry, Helvin, James Rogers
• Primary Examiner(s): Gregory, Bernarr E.
• Assistant Examiner(s): ANDREA, BRIAN K
• Application Number:
  US10/393,731
• Publication Number:
  US 20040056791A1
• Time in Patent Office: 704 Days
• Field of Search: 342/26, 342/188, 342/460, 702 2- 4
• US Class Current: 342/26.00D
• CPC Class Codes: G01S 13/95 for meteorological use
• CPC Class Codes: G01S 13/951 ground based
• 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: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A simultaneous dual polarization radar system is disclosed that utilizes a RF power divider to replace the high speed dual polarization switches utilized in current dual polarization radar systems. The disclosed systems allow for transmission and reception in both horizontal and vertical signal modes simultaneously while repositioning critical receiver components above the elevation rotary coupler in a radar pedestal. A bypass switch is also utilized to allow for mode switching of a radar system and a dual polarization reception design is shown to allow for the economical capturing of linear depolarization ratios of selected atmospheric areas. These new designs eliminate the current problems experienced in current dual polarization radar system of long dwell times and velocity range reductions, and the elimination of the relatively expensive and unreliable polarization switch.

Claims

1. A weather radar system, comprising:

a. an energy pulse train generator for producing radio emissions adapted for weather radar use;

b. a radio frequency power divider in electrical communication with said pulse train generator for splitting said radio emissions into simultaneous dual emission components;

c. an antenna in electrical communication with said power divider for transmitting said simultaneous dual emission components into space in a controlled manner and for collecting reflected signals from objects of interest;

d. an orthomode feed horn positioned on said antenna for altering one of said emission components to have a different phase relative to said other emission component during transmission and for collecting reflectivity signals of disparate phase relative to one another;

e. a receiver subsystem in electrical communication with said antenna for processing reflectivity signals collected by said antenna, wherein said receiver subsystem is co-located with said power divider to reduce phase error introductions;

f. a pair of channel circulators in electrical communication with said antenna, said power divider, and said receiver subsystem for isolating said dual emission components from said receiver subsystem; and

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g. a bypass switch in electrical communication with said pulse train generator and said antenna to selectively allow full radio emissions transmission power to be transferred to said antenna.

2. A radar system as recited in claim 1, further comprising a single channel rotary coupler connecting said energy pulse train generator to said power divider.

3. A radar system as recited in claim 2, wherein said energy pulse train generator comprises a Klystron signal generator and wherein said radar system further comprises a reference signal tap in electrical communication with one of said circulators to provide a reference signal to said klystron signal generator.

4. A radar system as recited in claim 3, wherein said receiver subsystem includes dual channels for simultaneously receiving orthogonally phased radar reflections.

23. A radar system as recited in claim 1, wherein said antenna is parabolic in shape.

33. A radar system as recited in claim 1, wherein said radio emissions generating means comprises a Klystron signal generator and wherein said radar system further comprises a reference signal tap in electrical communication with one of said isolating means to provide a reference signal to said klystron signal generator.

5. A weather radar system, comprising:

a. an energy pulse train generator for producing radio emissions adapted for weather radar use;

b. a radio frequency power divider in electrical communication with said pulse train generator for splitting said radio emissions into simultaneous dual emission components;

c. an antenna in electrical communication with said power divider for transmitting said simultaneous dual emission components into space in a controlled manner and for collecting reflected signals from objects of interest;

d. an orthomode feed horn positioned on said antenna for altering one of said emission components to have a different phase relative to said other emission component by 90 degrees during transmission and for collecting reflectivity signals of disparate phase relative to one another;

e. a receiver subsystem in electrical communication with said antenna for processing reflectivity signals collected by said antenna, wherein said receiver subsystem is co-located with said power divider to reduce phase error introductions;

f. a pair of channel circulators in electrical communication said antenna, said power divider, and said receiver subsystem for isolation said dual emission components from said receiver subsystem;

g. a bypass switch in electrical communication with said pulse train generator and said antenna to selectively allow full radio emissions transmission power to be transferred to said antenna;

h. a single channel rotary coupler connecting said energy pulse train generator to said power divider;

i. a radar signal processor in electrical communication with said receiver subsystem for processing reflected signal returns received by said receiver subsystem; and

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j. a wave guide signal port located between said power divider and said energy pulse train generator for extracting a reference signal from said radio emissions for use by said receiver subsystem.

6. A radar system as recited in claim 5, wherein said receiver subsystem includes dual channels for simultaneously receiving orthogonally phased radar reflections.

7. A radar system as recited in claim 6, wherein said energy pulse train generator comprises a Klystron signal generator and wherein said radar system further comprises a reference signal tap in electrical communication with one of said circulators to provide a reference signal to said klystron signal generator.

8. A radar system as recited in claim 7, wherein said radar signal processor is in electrical communication with a remote terminal for remote viewing of processed radar data.

9. A radar system as recited in claim 8, wherein said antenna is parabolic in shape.

10. A weather radar system, comprising:

a. an energy pulse train generator for producing radio emissions adapted for weather radar use;

b. a radio frequency power divider in electrical communication with said pulse train generator for splitting said radio emissions into simultaneous dual emission components;

c. an antenna in electrical communication with said power divider for transmitting said simultaneous dual emission components into space in a controlled manner and for collecting reflected signals from objects of interest;

d. an orthomode feed horn positioned on said antenna for altering one of said emission components to have a different phase relative to said other emission component by 90 degrees during transmission an for collecting reflectivity signals of disparate phase relative to one another;

e. a receiver subsystem in electrical communication with said antenna for processing reflectivity signals collected by said antenna, wherein said receiver subsystem is co-located with said power divider to reduce phase error introductions;

f. a pair of channel circulators in electrical communication with said antenna, said power divider, and said receiver subsystem for isolating said dual emission components from said receiver subsystem;

g. a bypass switch in electrical communication with said pulse train generator and said antenna to selectively allow full radio emissions transmission power to be transferred to said antenna;

h. wherein said energy pulse train generator comprises a Klystron signal generator and wherein said radar system further comprises a reference signal tap in electrical communication with one of said circulators to provide a reference signal to said Klystron signal generator; and

,

i. a single channel rotary coupler connecting said Klystron signal generator to said power divider.

11. A weather radar system, comprising:

a. means for generating radio emissions adapted for weather radar use;

b. means in electrical communication with said generating means for dividing said radio emissions into simultaneous dual emission components;

c. an antenna for transmitting said simultaneous dual emission components into space in a controlled manner and for collecting reflect signals from objects of interest;

d. means positioned on said antenna for altering one of said emission components to have a different phase relative to said other emission component during transmission and for collecting reflectivity signals of disparate phase relative to one another;

e. means in electrical communication with said antenna for receiving reflectivity signals collected by said antenna, wherein said receiving means is co-located with said radio emissions dividing means to reduce phase error introductions; and

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f. first and second means in electrical communication with said antenna, said dividing means, and said receiving means for isolating said dual emission components from said receiving means; and

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g. means in electrical communication with said emissions generator means and said antenna for bypassing said radio emissions divider means to selectively allow full radio emissions transmission power to be transferred to said antenna.

12. A radar system as recited in claim 11, further comprising a single channel rotary coupler connecting said emissions generator means to said radio emissions divider means.

13. A radar system as recited in claim 12, wherein said emissions generator means comprises a Klystron signal generator and wherein said radar system further comprises a reference signal tap in electrical communication with one of said first or second isolating means to provide a reference signal to said klystron signal generator.

14. A radar system as recited in claim 13, wherein said receiving means includes dual channels for simultaneously receiving orthogonally phased radar reflections.

15. A weather radar system, comprising:

a. an energy pulse train generator for producing radio emissions adapted for weather radar use;

b. a radio frequency power divider for splitting said radio emissions into simultaneous dual emission components;

c. an antenna for transmitting said simultaneous dual emission components into space in a controlled manner and for collecting reflected signals from objects of interest;

d. an orthomode feed horn adjacent to said antenna for altering one of said emission components to have a different phase relative to said other emission component during transmission and for collecting reflectivity signals of disparate phase relative to one another;

e. a receiver subsystem for processing reflectivity signals collected by said antenna, wherein said receiver subsystem is co-located with said power divider to reduce phase error introductions;

f. a pair of channel circulators for isolating said dual emission components from said receiver subsystem; and

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g. a bypass switch having a first switch element positioned between said radio frequency power divider and said energy pulse train generator and a second switch element positioned between said radio frequency power divider and one of said channel circulators.

16. A radar system as recited in claim 15, further comprising a single channel rotary coupler connecting said energy pulse train generator to said power divider, wherein said first switch element is located above said rotary coupler.

17. A radar system as recited in claim 16, further including a wave guide signal port located above said rotary coupler and electrically located between said power divider and said energy pulse train generator for extracting a reference signal from said radio emissions for use by said receiver subsystem.

18. A radar system as recited in claim 17, wherein said receiver subsystem includes dual channels for simultaneously receiving orthogonally phased radar reflections.

19. A radar system as recited in claim 18, wherein said power divider is electrically located between said antenna and said rotary coupler, and wherein said radar system further comprises a radar signal processor in electrical communication with said receiver subsystem and collocated therewith for processing reflected signal returns received by said receiver subsystem.

20. A radar system as recited in claim 19, wherein said antenna is parabolic in shape.

21. A radar system as recited in claim 19, wherein said radar signal processor is in electrical communication with a remote terminal for remote viewing of processed radar data.

22. A radar system as recited in claim 15, wherein said energy pulse train generator comprises a Klystron signal generator and wherein said radar system further comprises a reference signal tap in electrical communication with one of said circulators to provide a reference signal to said klystron signal generator.

24. A weather radar system, comprising:

a. means for generating radio emissions adapted for weather radar use;

b. means in electrical communication with said generating means for dividing said radio emissions into simultaneous dual emission components;

c. an antenna for transmitting said simultaneous dual emission components into space in a controlled manner and for collecting reflected signals from objects of interest;

d. means positioned on said antenna for altering one of said emission components to have a different phase relative to said other emission component during transmission and for collecting reflectivity signals of disparate phase relative to one another;

e. means in electrical communication with said antenna for receiving reflectivity signals collected by said antenna, wherein said receiving means is co-located with said radio emissions dividing means to reduce phase error introductions; and

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f. first and second means in electrical communication with said antenna, said dividing means, and said receiving means for isolating said dual emission components from said receiving means; and

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g. means for bypassing said radio emission dividing means.

25. A radar system as recited in claim 24, further comprising a single channel rotary coupler connecting said radio emissions generating means to said radio emissions dividing means.

26. A radar system as recited in claim 25, wherein said receiver means includes dual channels for simultaneously receiving orthogonally phased radar reflections.

27. A radar system as recited in claim 26, wherein said radar system further comprises a radar signal processor in electrical communication with said receiver means and collocated therewith for processing reflected signal returns received by said receiver means.

28. A radar system as recited in claim 27, wherein said phase altering means produces dual emission components substantially out of phase with each other by 90 degrees.

29. A radar system as recited in claim 25, wherein said radio emissions generating means comprises a Klystron signal generator and wherein said radar system further comprises a reference signal tap in electrical communication with one of isolating means to provide a reference signal to said klystron signal generator.

30. A radar system as recited in claim 29, wherein said antenna is parabolic in shape.

31. A radar system as recited in claim 30, wherein said phase altering means produces dual emission components substantially out of phase with each other by 90 degrees.

32. A radar system as recited in claim 25, further including a wave guide signal port located between said radio emissions dividing means and said radio emissions generating means for extracting a reference signal from said radio emissions for use by said receiver means.

34. A method for utilizing polarized radio emissions in a radar system having a radio emission power divider to enhance weather reflectivity data, the steps comprising:

a. generating a radio emission suitable for radar system usage;

b. selectively causing said radio emissions to bypass said radio emission power divider to allow for full power radio emissions to propagate from said radar system;

c. passing said emission components through an orthomode feed horn to potentially alter the phase of one of said components by substantially 90 degrees;

d. directing full power emissions into space in a controlled manner;

e. collecting polarized emission reflections from objects of interest;

f. passing said collected polarized emission reflections to a receiver subsystem; and

,

g. processing said reflections in a receiver subsystem to produce radar acquisition data.

35. A method as recited in claim 34, wherein said radar system includes at least one rotary coupling to assist in said directing step and wherein said processing step occurs in a receiver subsystem located above said at least one rotary coupling.

36. A method as recited in claim 34, further comprising the step of conducting said radio emissions from a radio emission generator to a radio frequency power divider through a single channel rotary coupler.

37. A method as recited in claim 34, wherein said processing step occurs without passing said collected polarized emission reflections through a rotary joint coupling.

38. A weather radar system, comprising:

a. an energy pulse train generator for producing radio emissions adapted for weather radar use;

b. a radar transceiver in electrical communication with said train generator, comprising;

i. a radio frequency power divider for splitting said radio emissions into simultaneous dual emission components;

ii. an antenna for transmitting said simultaneous dual emission components into space in a controlled manner and for collecting reflected signals from objects of interest;

iii. an orthomode feed horn adjacent to said antenna for altering one of said emission components to have a different phase relative to said other emission component during transmission and for collecting reflectivity signals of disparate phase relative to one another;

iv. an azimuth rotary coupling to allow rotation of said antenna;

v. an elevation rotary coupling positioned proximal to said azimuth rotary coupling to allow declination and elevation of said antenna;

vi. a receiver subsystem positioned above said elevation and azimuth couplings for processing reflectivity signals collected by said antenna; and

,

vii. a pair of channel circulators for isolating said dual emission components from said receiver subsystem; and

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c. a pedestal for supporting said transceiver; and

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d. a bypass switch in electrical communication with said pulse train generator and said antenna to selectively allow full radio emissions transmission power to be transferred to said antenna around said power divider.

39. A radar system as recited in claim 38, wherein said pedestal further comprises a single channel rotary coupler electrically connecting said energy pulse train generator to said power divider.

40. A radar system as recited in claim 39, wherein said energy pulse train generator comprises a Klystron signal generator and wherein said radar system further comprises a reference signal tap in electrical communication with one of said circulators to provide a reference signal to said klystron signal generator.

41. A radar system as recited in claim 38, further including a wave guide signal port electrically located between said power divider and said energy pulse train generator for extracting a reference signal from said radio emissions for use by said receiver subsystem.

42. A radar system as recited in claim 41, wherein said orthomode feed horn produces dual emission components substantially out of phase with each other by 90 degrees.

43. A weather radar system, comprising:

a. means for generating radio emissions adapted for weather radar use;

b. a radar transceiver in electrical communication with said pulse train generator, comprising;

i. means in electrical communication with said generating means for dividing said radio emissions into simultaneous dual emission components;

ii. an antenna for transmitting said simultaneous dual emission components into space in a controlled manner and for collecting reflected signals from objects of interest;

iii. means positioned on said antenna for altering one of said emission components to have a different phase relative to said other emission component during transmission and for collecting reflectivity signals of disparate phase relative to one another;

iv. means to allow rotation of said antenna;

v. means to allow raising and lowering of the elevation angle of said antenna;

vi. means in electrical communication with said antenna for receiving reflectivity signals collected by said antenna, wherein said receiving means is co-located with said radio emissions dividing means to reduce phase error introductions; and

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vii. first and second means in electrical communication with said antenna, said dividing means, and said receiving means for isolating said dual emission components from said receiving means; and

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c. means for providing a pedestal support for said transceiver; and

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d. means in electrical communication with said radio emissions generating means and said antenna for bypassing said dividing means to selectively allow full radio emissions transmission power to be transferred to said antenna.

44. A radar system as recited in claim 43, wherein said rotation and elevation means each comprise a single channel rotary coupler connecting said radio emissions generating means to said radio emissions dividing means.

45. A radar system as recited in claim 44, further including a wave guide signal port electrically located between said radio emissions dividing means and said radio emissions generating means for extracting a reference signal from said radio emissions for use by said receiver means.