Encoded transmitted signals in a simultaneous dual polarization weather system

• US 20070222660A1
• Filed: 03/22/2006
• Published: 09/27/2007
• Est. Priority Date: 03/22/2006
• Status: Active Grant

• Current Assignee: Enterprise Electronics
• Original Assignee: Enterprise Electronics
• Inventors: Alford, James, Stagliano, James, Helvin, James, Nelson, Dean
• Granted Patent: US 7,439,899 B2
• Time in Patent Office: Days
• US Class Current: 342/26.R
• 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 7/285 Receivers
• 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 system for simultaneously propagating dual polarized signals in a polarimetric radar system includes a system for coding at least one of the two signals. The simultaneous dual polarization weather radar transmits signals in both the horizontal and vertical orientations at the same time. Upon reception, the signals in each channel are decoded and a number of standard and polarimetric parameters characterizing atmospheric conditions are determined. The accuracy upon which these parameters can be determined depends partially upon the interference between these two channels. The system and method isolates the vertical and horizontal channels to minimize the interference.

Claims

1. A radar system comprising:

a. a waveform generator configured to generate a first signal and a second signal, said first signal having a different shape from said second signal;

b. amplifiers configured to amplify said first and second signals;

c. an antenna configured to simultaneously propagate said amplified first signal in a first plane and said amplified second signal in a second plane angularly rotated from said first plane; and

d. a receiver configured to receive a first reflected signal having the shape of said first signal and a second reflected signal having a shape of said second amplified signal.

2. The radar system of claim 1, wherein said first plane is orthogonal to said second plane.

3. The radar system of claim 1, wherein said first signal is shaped orthogonal to said second signal.

4. The radar system of claim 1, wherein said waveform generator generates said first and second signals at an intermediate frequency less than the frequency of said propagated first and second signals.

5. The radar system of claim 4, further comprising a stable local oscillator configured to generate a stable oscillating signal at a frequency equal to the difference between said propagated frequency and said intermediate frequency.

6. The radar system of claim 5, further comprising a mixer configured to mix said first and second signals with said stable oscillating signal.

7. The radar system of claim 6, wherein said first and second signals are mixed with said stable oscillating signal prior to the amplification of said first and second signals.

8. The radar system of claim 7, further comprising a pair of mixers configured to mix said stable oscillating signal with said first and second reflected signals.

9. The radar system of claim 1, wherein said receiver is further configured to receive said first and second signals from said waveform generator.

10. The radar system of claim 9, wherein said receiver isolates said first and second reflected signals by comparing said first and second received signals to said first and second signals received from said waveform generator.

11. The radar system of claim 1, wherein said antenna is further configured to receive said first and second reflected signals.

12. The radar system of claim 11 wherein said antenna receives said first and second reflected signals received in said first and second plane.

13. The radar system of claim 12 wherein said first plane is orthogonal to said second plane.

14. The radar system of claim 12 wherein:

a. said antenna is further configured to receive a first planar signal including a portion of said first reflected signal and a portion of said second reflected signal;

b. said antenna is further configured to receive a second planar signal including a portion of said first reflected signal and a portion of said second reflected signal; and

c. said receiver is further configured to calculate an angular rotation of said first and second reflected signal from said first and second plane.

15. A method for processing simultaneous dual polarized signals from a radar system, comprising the steps of:

a. receiving a first signal from a reflected source, said first received signal including a portion of a first transmitted signal and a portion of a second transmitted signal, said first transmitted signal shaped differently than said second transmitted signal;

b. receiving a second signal from a reflected source, said second received signal including a portion of said first transmitted signal and a portion of said second transmitted signal; and

c. decoding said first and second received signals by comparing said first transmitted signal with said first and second received signals.

16. The method of claim 15, further comprising the step of comparing said second transmitted signal with said first and second received signals.

17. The method of claim 16, further comprising receiving said first and second received signals simultaneously.

18. The method of claim 15 wherein said first transmitted signal is orthogonal to said second transmitted signal.

19. The method of claim 18, wherein said first transmitted signal and said first received signal are located in a first plane and said second transmitted signal and said second received signal are located in a second plane.

20. The method of claim 19, wherein said first plane is orthogonal to said second plane.

21. A radar system comprising:

a. an oscillator configured to generate a low power signal;

b. an amplifier configured to amplify said low power signal to a high power signal;

c. a power divider configured to split said high power signal into a first amplified signal and a second amplified signal;

d. a high powered coding device configured to inject a code into said first signal;

e. an antenna configured to simultaneously propagate said amplified first signal in a first plane and said amplified second signal in a second plane angularly rotated from said first plane; and

f. a receiver configured to receive a first reflected signal having the shape of said first signal and a second reflected signal having a shape of said second amplified signal.

22. The radar system of claim 21, wherein said first plane is orthogonal to said second plane.

23. The radar system of claim 21, wherein said first amplified signal is identical to said second amplified signal.

24. The radar system of claim 21, further comprising a second high powered coding device configured to code said second amplified signal wherein said oscillator generates said first and second signals at an intermediate frequency less than the frequency of said propagated first and second signals.

25. The radar system of claim 24, wherein said high power devices are configured to generate a first and second code at a frequency equal to the difference between said propagated frequency and said intermediate frequency.

26. The radar system of claim 25, wherein said first code is orthogonal to said second code.

27. The radar system of claim 26, further comprising a pair of mixers configured to mix said low power signal with said first and second reflected signals.

28. The radar system of claim 27, wherein said first and second codes are sent to said receiver.

29. The radar system of claim 21, wherein said receiver is further configured to receive said code from said high powered coding device.

30. The radar system of claim 29, wherein said receiver isolates said first and second reflected signals by comparing said first and second received signals to said code.

31. The radar system of claim 21, wherein said antenna is further configured to receive said first and second reflected signals.

32. The radar system of claim 21 wherein said antenna receives said first and second reflected signals received in said first and second plane.

33. The radar system of claim 32 wherein said first plane is orthogonal to said second plane.

34. The radar system of claim 32 wherein:

a. said antenna is further configured to receive a first planar signal including a portion of said first reflected signal and a portion of said second reflected signal;

b. said antenna is further configured to receive a second planar signal including a portion of said first reflected signal and a portion of said second reflected signal; and

c. said receiver is further configured to calculate an angular rotation of said first and second reflected signal from said first and second plane.

35. A method for propagating simultaneous dual polarized signals from a radar system, comprising the steps of:

a. generating a first signal and a second signal at an intermediate frequency;

b. coding said first signal with a coded signal such that said first signal and said second signal are shaped differently; and

c. propagating said first signal on a first plane and said second signal on a second plane, said second plane rotated from said first plane.

36. The method of claim 35, wherein said first plane is orthogonal to said second plane.

37. The method of claim 35, further comprising propagating said first and second signals simultaneously.

38. The method of claim 35 wherein said first signal is orthogonal to said second signal.

39. The method of claim 38, wherein said first signal and a first received signal are received in said first plane and said second signal and a second received signal are received in said second plane.

40. The method of claim 39, wherein said first plane is orthogonal to said second plane.

41. The method of claim 40, further comprising:

a. decoding said first and second received signals by comparing said first signal with said first and second received signals;

b. wherein said first received signal includes a portion of a first transmitted signal and a portion of a second transmitted signal; and

c. said second received signal includes a portion of said first transmitted signal and a portion of said second transmitted signal.

42. The method of claim 41, further comprising the step of comparing said second transmitted signal with said first and second received signals.

43. The method of claim 42, further comprising receiving said first and second received signals simultaneously.