METHODS AND APPARATUS FOR ELECTROMAGNETIC SIGNAL POLARIMETRY SENSING

• US 20130332115A1
• Filed: 03/15/2013
• Published: 12/12/2013
• Est. Priority Date: 01/13/2012
• Status: Active Grant

• Current Assignee: University of Notre DAME Du Lac
• Original Assignee: University of Notre DAME Du Lac
• Inventors: Pratt, Thomas G., Mueller, Jeffrey George
• Granted Patent: US 9,857,316 B2
• Time in Patent Office: Days
• US Class Current: 702/190
• CPC Class Codes: G01N 22/04 Investigating moisture content
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• 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: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A system and method of identifying changes utilizing radio frequency polarization includes receiving a reflected and/or transmitted polarized radio frequency signal at a receiver, filtering, amplifying and conditioning the received signal, converting the received signal from an analog format to a digital format, processing the digital signal to elicit a polarization mode dispersion feature of the received signal, and comparing the polarization mode dispersion features to a known calibration to detect a change in a characteristic of the target object.

Claims

1. A method of identifying changes utilizing polarization comprising:

receiving polarized components of at least a partially polarized signal at a receiver, the signal being at least one of reflected or transmitted through a target object;

processing the signal to elicit a polarization feature of the received signal; and

correlating a change in a polarization response of the target object

2. A method as defined in claim 1, wherein detecting a change in the polarization response of the target further comprises comparing the polarization features to a known calibration.

3. A method as defined in claim 2, wherein the known calibration is determined by measuring the polarization signature and comparing the measured polarization signature to a known standard measurement.

4. A method as defined in claim 1, wherein detecting a change in the polarization response of the target further comprises comparing the polarization mode dispersion features to a previously elicited polarization mode dispersion feature of the received signal

5. A method as defined in claim 1, wherein detection of a change in a characteristic of the target object comprises detection of at least one of vibration, position change, attitude change, mechanical fault, electrical fault, electromagnetism, reflectivity, liquid phase, solid phase, structural change, or foreign object contamination of the target object.

6. A method as defined in claim 1, wherein elicitation of the polarization mode dispersion feature of the received signal comprises computing a Stokes Parameter versus a frequency index.

7. A method as defined in claim 1, wherein the known calibration is a predictive model and wherein comparing the polarization mode dispersion features to the known calibration allows for prediction of an impending change in the target object.

8. A method as defined in claim 1, wherein the received polarimetric feature in a first subband is compared against a received polarimetric feature of a second subband.

9. A method as defined in claim 1, wherein the polarimetric feature is the polarimetric mode dispersion of at least one subband of the received signal.

10. A system for identifying changes utilizing polarization comprising:

a polarized receiver for receiving a polarized signal at a receiver, the signal being at least one of reflected or transmitted through a target object;

a signal filter for filtering the received signal;

a signal amplifier for amplifying the received signal;

a signal conditioner for conditioning the received signal;

an analog to digital converted for converting the signal from an analog format to a digital format;

a processor for processing the digital signal to elicit a polarization mode dispersion feature of the received signal; and

wherein the processor detects a change in a characteristic of the target object.

11. A system as defined in claim 10, wherein the processor detects the change in a characteristic of the target response by comparing the polarization mode dispersion features to a known calibration stored in a memory.

12. A system as defined in claim 11, wherein the known calibration is determined by measuring the polarization mode dispersion signature and comparing the measured polarization mode dispersion signature to a known standard measurement.

13. A system as defined in claim 10, wherein detection of a change in a characteristic of the target object comprises detection of at least one of vibration, position change, attitude change, mechanical fault, electrical fault, electromagnetism, reflectivity, liquid phase, solid phase, structural change, or foreign object contamination of the target object.

14. A system as defined in claim 10, wherein elicitation of the polarization mode dispersion feature of the received signal comprises computing a Stokes Parameter versus a frequency index.

15. A method of identifying changes utilizing electromagnetic signal polarization comprising:

receiving polarized components of at least a partially polarized electromagnetic signal at a receiver, the signal being at least one of reflected or transmitted through a target object;

converting the received signal from an analog format to a digital format;

processing the digital signal to elicit a polarization mode dispersion feature of the received signal; and

detecting a change in a polarization response of the target object.