STABILITY MONITORING USING SYNTHETIC APERTURE RADAR

• US 20100045513A1
• Filed: 08/22/2008
• Published: 02/25/2010
• Est. Priority Date: 08/22/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Paden, John D., Wu, Xiaoqing, Ashby, Malcolm William II, Brewster, Lawrence, Pett, Todd, Curlander, John
• Granted Patent: US 8,154,435 B2
• Time in Patent Office: Days
• US Class Current: 342/25.C
• CPC Class Codes: G01S 13/867 Combination of radar systems with cameras
• CPC Class Codes: G01S 13/9023 combined with interferometric techniques
• CPC Class Codes: G01S 7/295 Means for transforming co-ordinates or for evaluating data, e.g. using computers
• CPC Class Codes: G01S 7/4091 during normal radar operation

Abstract

A stability monitoring system is described that provides an accurate, automated, and remote way of monitoring small movements over a large surface area without the need to pre-place reflective targets using a mobile SAR. The stability monitoring system allows the rapid, automated identification and measurement of small surface movements over a wide field of view from a safe standoff distance without the need for personnel working in hazardous zones. Using this data, authorities can more accurately identify hazard areas and efficiently allocate mitigation resources.

Claims

1. A computer-implemented method for monitoring a slope capable of detecting small surface displacements using intermittent measurement intervals spread over an extended period, the method comprising:

at a current measurement interval, capturing radar information associated with the slope;

applying synthetic aperture radar processing to the radar information to produce one or more synthetic aperture radar images;

retrieving radar information associated with the slope from a previous measurement interval;

applying interferometry to the captured radar information from the current measurement interval and retrieved radar information from the previous measurement interval to produce a displacement map indicative of movement of the slope over time; and

displaying the displacement map to an operator.

2. The method of claim 1 wherein capturing radar information comprises sparsely sampling the radar return from the slope to reduce the measuring time.

3. The method of claim 1 further comprising applying target classification to detect and remove errors in the radar information.

4. The method of claim 1 further comprising performing adaptive region-growing to detect and improve faults in the radar information.

5. The method of claim 1 wherein applying synthetic aperture radar processing comprises applying interferometric synthetic aperture radar processing to generate a digital elevation model of the slope.

6. The method of claim 5 wherein applying interferometric synthetic aperture radar processing comprises performing at least one of multi-baseline differential interferometric synthetic aperture radar and polarimetric differential interferometric synthetic aperture radar to improve robustness.

7. The method of claim 1 wherein applying synthetic aperture radar processing and interferometry comprise applying an iterative process that feeds data processing results back to improve measurement accuracy.

8. The method of claim 1 further comprising calibrating the synthetic aperture radar images to account for differences in a measurement location of the current measurement interval and a measurement location of the previous measurement interval.

9. The method of claim 1 further comprising overlaying a displacement map onto an optical image of the slope that is draped on a digital elevation model and displaying the result to the operator.

10. A computer system for monitoring movement of a geophysical region over time, the system comprising:

a radar component configured to collect radar information about the geophysical region;

a geophysical data store configured to store information about the geophysical region, wherein the stored information includes previously collected radar information;

a data processing component configured to process the collected radar information and previously collected radar information to detect movements in the geophysical region; and

a user interface component configured to report results of the data processing component to an operator of the system.

11. The system of claim 10 wherein the radar component is a ground-based synthetic aperture radar operating from a mobile platform with two-dimensional scan capability.

12. The system of claim 10 wherein the data processing component is further configured to employ interferometric synthetic aperture radar and differential interferometric synthetic aperture radar processing to measure surface displacements of the geophysical region with high resolution.

13. The system of claim 10 wherein the system is configured to be re-deployed between measurement intervals to allow the system to be used across multiple geophysical regions.

14. The system of claim 10 further comprising an optical component configured to collect optical information about the geophysical region and wherein the data processing component is further configured to overlay the collected radar information on the collected optical information.

15. The system of claim 10 further comprising a calibration component configured to calibrate the system using reflective targets.

16. The system of claim 10 wherein the user interface component is further configured to receive an alarm threshold from the operator that indicates a threshold of movement for which the operator requests notification.

17. A computer-readable medium encoded with instructions for controlling a computer system to display movement of a rock wall, by a method comprising:

identifying a location for placing a mobile synthetic aperture radar device, wherein the location has a possibility of rock fall;

performing a series of radar scans of the location from the mobile synthetic aperture radar device;

storing information associated with the series of radar scans in a data store;

after a period over which the location may have changed,

performing a second series of radar scans of the location;

comparing the first series of radar scans with the second series of radar scans to identify movement indicative of a potential rock fall; and

displaying results associated with the identified movement.

18. The computer-readable medium of claim 17 wherein performing a series of radar scans does not include using pre-placed reflective targets.

19. The computer-readable medium of claim 17 further comprising for any identified movement, determining the rate of acceleration of the movement based on multiple series of radar scans.

20. The computer-readable medium of claim 17 further comprising, if movement indicative of a potential rock fall is identified, notifying an operator to schedule mitigation of the potential rock fall.