RADIO FREQUENCY DEVICE FOR UNMIXING POLARIZED SIGNALS AND ASSOCIATED METHODS

• US 20090079646A1
• Filed: 09/21/2007
• Published: 03/26/2009
• Est. Priority Date: 09/21/2007
• Status: Abandoned Application

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: OLSEN, Arthur S.
• Application Number:
  US11/859,137
• Publication Number:
  US 20090079646A1
• Time in Patent Office: Days
• US Class Current: 343/756
• CPC Class Codes: H01Q 25/001 Crossed polarisation dual antennas orthomode horns H01Q13/0258; cross-polarised rear feeds H01Q19/136; orthomode transducers H01P1/161

Abstract

A radio frequency (RF) device includes an antenna array for receiving dual polarized RF signals, and in-phase and quadrature modules coupled to the antenna array for generating in-phase and quadrature components. A homology group matched filter is coupled to the in-phase and quadrature modules for determining an unmixing equation for generating unmixed dual polarized RF signals, and for applying at least one estimated source polarization homology parameter to the unmixing equation. An unmixed dual polarized RF signal level is generated by the homology group matched filter based upon the at least one estimated source polarization homology parameter and the unmixed dual polarized RF signals. A threshold detector is coupled to the homology grouped matched filter for determining if the unmixed dual polarized RF signal level is above a threshold.

Claims

1. A radio frequency (RF) device comprising:

an antenna array for receiving dual polarized RF signals;

a plurality of in-phase and quadrature modules coupled to said antenna array for generating a plurality of in-phase and quadrature components;

a homology group matched filter coupled to said plurality of in-phase and quadrature modules for

determining an unmixing equation for generating unmixed dual polarized RF signals,

applying at least one estimated source polarization homology parameter to the unmixing equation, and

generating an unmixed dual polarized RF signal level based upon the at least one estimated source polarization homology parameter and the unmixed dual polarized RF signals; and

a threshold detector coupled to said homology grouped matched filter for determining if the unmixed dual polarized RF signal level is above a threshold.

2. The RF device according to claim 1 wherein the dual polarized RF signals comprise elliptically polarized signals.

3. The RF device according to claim 1 wherein the at least one estimated source polarization homology parameter comprises a relative amplitude shift between the dual polarized RF signals, a relative phase shift between the dual polarized RF signals, and azimuth and elevation angles of a direction of the dual polarized RF signals.

4. The RF device according to claim 1 wherein applying the at least one estimated source polarization homology parameter to the unmixing equation comprises applying incremented estimated source polarization homology parameters to the unmixing equation, with an unmixed dual polarized RF signal level being generated for each incremented parameter.

5. The RF device according to claim 1 wherein said homology group matched filter applies a taper matrix to the unmixing equation for trading mainlobe gain for sidelobe suppression of said antenna array.

6. The RF device according to claim 1 wherein said antenna array comprises a plurality of paired antenna elements, with each paired antenna elements being dual polarized.

7. The RF device according to claim 6 wherein each paired antenna element comprises a horizontally polarized antenna element and a vertically polarized antenna element.

8. The RF device according to claim 6 wherein said plurality of in-phase and quadrature modules comprises a respective pair of in-phase and quadrature modules downstream from each paired antenna elements for generating a pair of in-phase and quadrature components.

9. The RF device according to claim 1 wherein said threshold detector comprises a constant false alarm rate (CFAR) detector.

10. The RF device according to claim 1 further comprising a transmitter for transmitting dual polarized signals so that the RF device is configured as a radar, with the received dual polarized RF signals being reflected off of an object receiving the transmitted dual polarized signals.

11. A radio frequency (RF) device comprising:

an antenna array for receiving elliptically polarized RF signals;

a plurality of in-phase and quadrature modules coupled to said antenna array for generating a plurality of in-phase and quadrature components;

a homology group matched filter coupled to said plurality of in-phase and quadrature modules for

generating a spectral results matrix based on the plurality of in-phase and quadrature components,

generating a polarization homology group matrix representing a polarized state of an estimated elliptically polarized signal source,

applying at least one estimated source polarization homology parameter to an unmixing equation for generating unmixed elliptically polarized RF signals, the unmixing equation defined by the spectral results matrix and the polarization homology group matrix, and

generating an unmixed elliptically polarized RF signal level based upon the at least one estimated source polarization homology parameter and the unmixed elliptically polarized RF signals; and

a threshold detector coupled to said homology grouped matched filter for determining if the unmixed elliptically polarized RF signal level is above a threshold.

12. The RF device according to claim 11 wherein the at least one estimated source polarization homology parameter comprises a relative amplitude shift between the elliptically polarized RF signals, a relative phase shift between the elliptically polarized RF signals, and azimuth and elevation angles of a direction of the elliptically polarized RF signals.

13. The RF device according to claim 11 wherein applying the at least one estimated source polarization homology parameter to the unmixing equation comprises applying incremented estimated source polarization homology parameters to the unmixing equation, with an unmixed elliptically polarized RF signal level being generated for each incremented parameter.

14. The RF device of claims 11 wherein each element in the polarization homology group matrix comprises at least one of a quanternion number corresponding to an estimated elliptically polarized signal source at an array element, a sum of two complex numbers corresponding to the estimated elliptically polarized signal source, and a Hamiltonian matrix whose norm is invariant in time and corresponds to the total energy-momentum of the desired elliptically polarized signal source.

15. The RF device according to claim 11 wherein said homology group matched filter applies a taper matrix to the unmixing equation for trading mainlobe gain for sidelobe suppression of said antenna array.

16. The RF device according to claim 11 wherein said antenna array comprises a plurality of paired antenna elements, with each paired antenna elements being elliptically polarized;

wherein each paired antenna element comprises a horizontally polarized antenna element and a vertically polarized antenna element.

17. The RF device according to claim 16 wherein said plurality of in-phase and quadrature modules comprises a respective pair of in-phase and quadrature modules downstream from each paired antenna elements for generating a pair of in-phase and quadrature components.

18. A method for unmixing dual polarized signals received by a radio frequency (RF) device comprising an antenna array, a plurality of in-phase and quadrature modules coupled to the antenna array, and a homology group matched filter coupled to the plurality of in-phase and quadrature modules, the method comprising:

receiving dual polarized RF signals at the antenna array;

generating a plurality of in-phase and quadrature components using the plurality of in-phase and quadrature modules;

determining in the homology group matched filter an unmixing equation for generating unmixed dual polarized RF signals;

applying at least one estimated source polarization homology parameter to the unmixing equation in the homology group matched filter;

generating in the homology group matched filter an unmixed dual polarized RF signal level based upon the at least one estimated source polarization homology parameter and the unmixed dual polarized RF signals; and

determining if the unmixed dual polarized RF signal level is above a threshold.

19. The method according to claim 18 wherein the dual polarized RF signals comprise elliptically polarized signals.

20. The method according to claim 18 wherein the at least one estimated source polarization homology parameter comprise a relative amplitude shift between the dual polarized RF signals, a relative phase shift between the dual polarized RF signals, and linear phase progressions related to azimuth and elevation angles of a direction of the dual polarized RF signals.

21. The method according to claim 18 wherein applying the at least one estimated source polarization homology parameter to the unmixing equation comprises applying incremented estimated source polarization homology parameters to the unmixing equation, with an unmixed dual polarized RF signal level being generated for each incremented parameter.

22. The method according to claim 18 further comprising applying a taper matrix to the unmixing equation for trading mainlobe gain for sidelobe suppression of the antenna array.

23. The RF device according to claim 18 wherein the antenna array comprises a plurality of paired antenna elements, with each paired antenna elements being dual polarized;

wherein each paired antenna element comprises a horizontally polarized antenna element and a vertically polarized antenna element.

24. The RF device according to claim 23 wherein said plurality of in-phase and quadrature modules comprises a respective pair of in-phase and quadrature modules downstream from each paired antenna elements for generating a pair of in-phase and quadrature components.