Systems and Methods for Mapping the Crust of the Earth

• US 20120268307A1
• Filed: 04/19/2011
• Published: 10/25/2012
• Est. Priority Date: 04/19/2011
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Tomich, John L., Samaniego, Raymond, Santiago, Enrique A., Priebe, Leslie A.
• Granted Patent: US 8,884,805 B2
• Time in Patent Office: Days
• US Class Current: 342/22
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence

Abstract

A system comprises a radar transmitter configured to generate a radar signal at a predetermined frequency and a radar receiver configured to receive a reflected signal produced by a reflection of the radar signal. The system further includes a radar antenna system configured to transmit the radar signal into a subterranean region and to receive the reflected signal from the subterranean region. A control system is used for controlling a dwell time of the radar antenna system, and a processor is adapted to generate an image of at least a portion of the subterranean region based at least in part on the reflected signal.

Claims

1. A system comprising

a radar transmitter configured to generate a radar signal at a predetermined frequency;

a radar receiver configured to receive a reflected signal produced by a reflection of the radar signal;

a radar antenna system configured to transmit the radar signal into a subterranean region and to receive the reflected signal from the subterranean region;

a control system for controlling a dwell time of the radar antenna system;

a processor adapted to generate an image of at least a portion of the subterranean region based at least in part on the reflected signal.

2. The system of claim 1 wherein the dwell time is greater than 1 hour.

3. The system of claim 1 wherein the dwell time is greater than 24 hours.

4. The system of claim 1 wherein the dwell time is greater than 7 days.

5. The system of claim 1 wherein the predetermined frequency is between 10 KHz and 300 MHz.

6. The system of claim 1 wherein the predetermined frequency is between 10 KHz and 100 MHz.

7. The system of claim 1 wherein the radar antenna system is one of a plurality of radar antenna systems in an antenna array and the antenna array is capable of receiving a plurality of reflected signals from the subterranean region.

8. The system of claim 7 wherein the processor is adapted for interferometric processing of the plurality of reflected signals.

9. The system of claim 1 wherein the radar antenna system includes a dipole antenna.

10. The system of claim 1 wherein the radar antenna system includes a transmit antenna portion spatially separated from a receive antenna portion.

11. A method comprising:

transmitting a radar signal at a predetermined frequency via a first radar antenna;

receiving, via a second radar antenna, a reflected signal produced by the radar signal reflected from a subterranean formation;

controlling a dwell time of the first and second radar antennas, wherein the dwell time is greater than one hour;

generating an image of the subterranean formation using the reflected signal.

12. The system of claim 11 wherein the dwell time is greater than 24 hours.

13. The method of claim 11 wherein the subterranean formation is located between 1 meter and 50 kilometer below ground.

14. The method of claim 11 wherein the image has a depth resolution of less than approximately 1 foot.

15. The method of claim 11 wherein a radar antenna array comprises the first and second radar antennas.

16. The method of claim 15 further comprising receiving, via a third radar antenna of the radar antenna array, another reflected signal produced by the radar signal reflected from the subterranean formation.

17. The method of claim 16 further comprising performing interferometric processing of a plurality of reflected signals received via the radar antenna array.

18. The method of claim 11 wherein the step of generating an image includes generating a Doppler image of subterranean fluid movement.

19. The method of claim 11 further comprising categorizing an aspect of the subterranean formation and assigning a property value to the subterranean formation based upon the aspect.

20. A system comprising:

a distributed radar array including a first transmitting antenna configured to transmit a first radar signal at a predetermined frequency into a subterranean region and a plurality of receiving antennas configured to receive a plurality of reflected signals of the first radar signal from the subterranean region;

a control system for controlling a dwell time of the first transmitting antenna and the plurality of receiving antennas;

a processor adapted to generate an image of at least a portion of the subterranean region based at least in part on the plurality of reflected signals.

21. The system of claim 20 wherein the distributed radar array further includes a second transmitting antenna configured to transmit a second radar signal at the predetermined frequency into the subterranean region and wherein the control system is adapted to halt the transmission of the first radar signal and initiate transmission of the second radar signal.

22. The system of claim 20 wherein the processor is adapted for interferometric processing of the plurality of reflected signals.

24. The distributed radar array system of claim 21 further comprising:

a control system configured to control the transmitter and receiver.

25. The distributed radar array system of claim 24 wherein the control system is configured to distribute a synchronized clock signal to at least a portion of the plurality of radar units.

26. The distributed radar array system of claim 24 wherein the control system is configured to distribute a local oscillator signal to at least a portion of the plurality of radar units.

27. The distributed radar array system of claim 24 further comprising a fiber optic connection to convey control instructions between the control system and the plurality of radar units.

28. The distributed radar array system of claim 27 wherein the fiber optic connection includes a time shared optic fiber.

29. The distributed radar array system of claim 24 wherein the control system is operable to select a first radar unit from the plurality of radar units to generate a first RF signal within the bandwidth at a first transmit time and is operable to select a second radar unit from the plurality of radar units to generate a second RF signal within the bandwidth at a second transmit time.

23. A distributed radar array system comprising:

a plurality of radar units, each unit including a waveform generator;

a transmitter, connected to the waveform generator, configured to generate RF signals within a bandwidth;

an antenna configured to couple to the earth for conveying the RF signals; and

a receiver configured to receive reflected signals of the RF signals from a subterranean region.

30. The distributed radar array system of claim 23 further comprising a processor configured to process the reflected signals.

31. The distributed radar array system of claim 30 wherein the processor is configured to process the reflected signals using an interferometric processing technique.

32. The distributed radar array system of claim 30 wherein the processor is configured to process the reflected signals using a tomographic three dimensional processing technique.