Simultaneous dual polarization radar system

• US 7,049,997 B2
• Filed: 11/09/2004
• Issued: 05/23/2006
• Est. Priority Date: 09/20/2002
• Status: Expired due to Term

• Current Assignee: Enterprise Electronics
• Original Assignee: Enterprise Electronics
• Inventors: Alford, James Larry, Helvin, James Rogers
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US10/984,259
• Publication Number:
  US 20050093734A1
• Time in Patent Office: 560 Days
• Field of Search: 342/26, 342/188, 342/460, 342/26.R, 342/26.D, 702 2- 4
• US Class Current: 342/26.00R
• CPC Class Codes: G01S 13/951 ground based
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G01S 7/024 using polarisation effects in waveguides H01P1/165; for aerials H01Q, e.g. H01Q15/22, H01Q15/24, H01Q19/195
• 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;

f. wherein said receiver subsystem is co-located with said power divider to reduce phase error introductions; and

,

g. 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.

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 orthomode feed horn produces dual emission components substantially out of phase with each other by 90 degrees.

4. A radar system as recited in claim 3, further comprising a radar signal processor in electrical communication with said receiver subsystem for processing reflected signal returns received by said receiver subsystem, wherein said radar signal processor is co-located with said power divider.

5. A radar system as recited in claim 4, further including 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 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.

7. A radar system as recited in claim 1, wherein said orthomode feed horn produces dual emission components substantially out of phase with each other by 90 degrees.

8. A radar system as recited in claim 7, further comprising a radar signal processor in electrical communication with said receiver subsystem for processing reflected signal returns received by said receiver subsystem, wherein said radar signal processor is co-located with said power divider.

9. A radar system as recited in claim 8, further including 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.

10. A radar system as recited in claim 9, further comprising single means for electrically connecting said energy pulse train generator to said power divider during rotation of said antenna.

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 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

,

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.

12. A radar system as recited in claim 11, wherein said phase altering means produces dual emission components substantially out of phase with one other by 90 degrees.

13. A radar system as recited in claim 12, further including a wave guide signal port located between said radio emissions divider means and said emissions generator means for extracting a reference signal from said radio emissions for use by said receiving means.

14. A radar system as recited in claim 13, further comprising a radar signal processor in electrical communication with said receiver means for processing reflected signal returns received by said receiver means, wherein said radar signal processor is co-located with said radio emissions divider means.

15. A radar system as recited in claim 13, further comprising a single channel rotary coupler connecting said emissions generator means to said radio emissions divider means.

16. A method for utilizing simultaneous dual polarized radio emissions in a radar system to enhance weather reflectivity data, the steps comprising:

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

b. splitting said radio emission into dual emission components;

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

d. simultaneously directing dual polarized emissions into space in a controlled manner;

e. collecting polarized emission reflections from objects of interest resulting from said step of directing said dual polarized emissions into space;

f. passing said collected polarized emission reflections to a receiver subsystem without passing said polarized emission reflections through a rotary joint coupling; and

,

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

17. A method as recited in claim 16, wherein said collecting step comprises the steps of collecting said emission reflections in an antenna and focusing said collected reflections into an orthomode feed horn to create separate reception signals substantially 90 degrees out of phase with one another.

18. A method as recited in claim 17, wherein said step of generating a radio emission suitable for radar system usage includes the utilization of a single channel rotary coupling to electrically connect a radio emission source to said orthomode feed horn and wherein said processing step occurs in a receiver subsystem located above said single channel rotary coupling.

19. A method as recited in claim 18, wherein said processing step occurs in a receiver subsystem co-located with a power divider.

20. A method as recited in claim 17, 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.

21. A method as recited in claim 20, wherein said processing step occurs in a receiver subsystem co-located with power divider.

22. A method as recited in claim 16, 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.

23. A method as recited in claim 16, wherein said processing step occurs in a receiver subsystem co-located with power divider.

24. 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 pulse 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 receiving 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.

25. A radar system as recited in claim 24, 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.

26. A radar system as recited in claim 25, further comprising a single channel rotary coupler connecting said energy pulse train generator to said power divider.

27. A radar system as recited in claim 26, further comprising a radar signal processor in electrical communication with said receiver subsystem for processing reflected signal returns received by said receiver subsystem.

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

29. 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 processing means is co-located with said radio emissions dividing means to reduce phase error introductions; and

,

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.

30. A radar system as recited in claim 29, 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.

31. A radar system as recited in claim 30, 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.

32. A radar system as recited in claim 31, wherein all of the components of said radar transceiver are co-located with one another.

33. A radar system as recited in claim 29, wherein all of the components of said radar transceiver are co-located with one another.