Off-diagonal element echo power estimator for polarization weather radar

• US 8,854,250 B2
• Filed: 06/28/2011
• Issued: 10/07/2014
• Est. Priority Date: 06/28/2011
• Status: Active Grant

• Current Assignee: Vaisala Oyj
• Original Assignee: Vaisala Oyj
• Inventors: Keranen, Reino, Venkatachalam, Chandrasekaran
• Primary Examiner(s): BYTHROW, PETER M
• Application Number:
  US13/170,994
• Publication Number:
  US 20130002475A1
• Time in Patent Office: 1,197 Days
• Field of Search: 342/26.R, 342/26.A, 342/26.B, 342/26.C, 342/26.D, 342/175, 342/188, 342/189
• US Class Current: 342/26.R
• 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 7/41 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• 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

Embodiments of the invention are directed to improving the sensitivity in polarimetric radar data. In particular, embodiments of the invention improve the sensitivity of such systems with improved post processing techniques. The sensitivity can be improved by using the co-polar elements (off diagonal elements) of the covariance matrix in power and/or reflectivity determinations. This can not only improve the sensitivity but may also enhance identification and improve quantitative estimates of precipitation.

Claims

1. A method comprising:

propagating a radar signal into a region of interest using a dual polarization radar transmitter;

collecting dual polarization radar echo data scattered form within the region of interest, wherein the radar echo data comprises horizontal and vertical complex voltages;

calculating, using an electronic computer processor, a covariance matrix from the radar echo data; and

estimating, using an electronic computer processor, precipitation profiles from an off-diagonal element of the covariance matrix.

2. The method according to claim 1, wherein the covariance matrix is the product of the horizontal complex voltages and vertical complex voltages.

3. The method according to claim 1, wherein the precipitation profile is estimated from the absolute power of the off-diagonal element of the covariance matrix.

4. The method according to claim 1 further comprising estimating a reflectivity from the covariance matrix.

5. The method according to claim 4, wherein the reflectivity is estimated using

6. A method comprising:

propagating a radar signal into a region of interest using a dual polarization radar transmitter;

collecting dual polarization radar data scattered form within the region of interest, wherein the radar data comprises horizontal and vertical complex voltages;

calculating a covariance matrix from the dual polarization radar data; and

estimating a reflectivity from an off-diagonal element of the covariance matrix.

7. The method according to claim 6, wherein the reflectivity is estimated from

8. A radar system comprising:

a transmitter configured to transmit polarized radar signals into a region of interest;

a receiver configured to receive a polarized data scattered from the region of interest, wherein the polarized data comprises horizontal and vertical complex voltages; and

a computer system coupled at least with the receiver, wherein the computer system is configured to calculate a covariance matrix of the polarized data and estimate a reflectivity of the region of interest using an off-diagonal element of the covariance matrix.

9. The radar system according to claim 8, wherein the reflectivity is estimated from the absolute power of an off-diagonal element of the covariance matrix.

10. The radar system according to claim 8, wherein the reflectivity is estimated using