Method and apparatus for acoustic detection of mines and other buried man-made objects

• US 6,415,666 B1
• Filed: 03/20/2000
• Issued: 07/09/2002
• Est. Priority Date: 10/07/1997
• Status: Expired due to Fees

• Current Assignee: Stevens Institute Of Technology
• Original Assignee: Stevens Institute Of Technology
• Inventors: Sutin, Alexander M., Donskoy, Dimitri M.
• Primary Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US09/462,956
• Time in Patent Office: 841 Days
• Field of Search: 736/27, 736/02, 735/99, 735/96, 367/87
• US Class Current: 73/627
• CPC Class Codes: F41H 11/12 Means for clearing land minefields; Systems specially adapted for detection of landmines
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 29/11 by measuring attenuation of acoustic waves
• CPC Class Codes: G01N 29/28 providing acoustic coupling , e.g. water impedance matching G10K11/02
• CPC Class Codes: G01N 29/40 by amplitude filtering, e.g. by applying a threshold or by gain control
• CPC Class Codes: G01N 29/46 by spectral analysis, e.g. Fourier analysis or wavelet analysis spectral signal processing per se G06F17/14
• CPC Class Codes: G01S 15/04 Systems determining presence of a target
• CPC Class Codes: G01S 15/86 Combinations of sonar systems with lidar systems; Combinations of sonar systems with systems not using wave reflection
• CPC Class Codes: G01S 15/88 Sonar systems specially adapted for specific applications seismic or acoustic prospecting or detecting G01V1/00
• CPC Class Codes: G01V 1/001 Acoustic presence detection

Abstract

In order to detect buried compliant objects such as land mines and pipes, an acoustic signal is directed into the ground to excite vibration of a buried compliant object. A probing signal is also directed into the ground toward the vibrating object, and the probing signal is modulated and reflected by the vibrating object. The modulated, reflected probing signal is processed to determine therefrom the presence of the buried compliant object.

Claims

1. An apparatus for detecting compliant buried objects comprising:

signal generating means for generating an acoustic signal having first and second frequencies for vibrating a compliant buried object;

RF signal generating means for generating an RF signal which is directed, separately from the acoustic signal, toward the vibrating buried object so that the vibrating buried object modulates the RF signal;

receiving means for receiving the RF signal after the RF signal is modulated by the vibrating buried object; and

processing means for processing the signal received by the receiving means.

2. The apparatus of claim 1;

wherein the signal generating means includes power amplifying means for amplifying the acoustic signal.

3. The apparatus of claim 2;

wherein the signal generating means generates a dual frequency acoustic signal.

4. The apparatus of claim 3 further comprising demodulation means for demodulating the received signal.

5. The apparatus of claim 4 wherein the RF signal generating means generates a ground penetrating RADAR signal.

6. A method of locating a buried compliant object, comprising the steps of:

producing an acoustic signal;

directing the acoustic signal at a buried compliant object to vibrate the object;

producing a second signal;

directing the second signal at the vibrating buried compliant object to cause the second signal to be modulated by the vibrating object; and

processing the modulated second signal to determine the presence of the buried compliant object.

7. The method of claim 6;

wherein the second signal comprises an RF signal.

8. The method of claim 7;

wherein the RF signal comprises a ground penetrating RADAR signal.

9. The method of claim 8 further comprising the step of demodulating the modulated second signal.

10. An apparatus for detecting buried compliant objects comprising:

a first signal generator for generating an acoustic signal to excite vibration of a buried compliant object;

a second signal generator for generating a probing signal which is directed separately from the acoustic signal toward and modulated by the vibrating buried compliant object;

a receiver disposed to receive the modulated probing signal; and

a processor connected to the receiver for processing the modulated probing signal to determine therefrom the presence of the buried compliant object.

11. An apparatus according to claim 10;

further including a sound source connected to the first signal generator for directing the acoustic signal toward the buried compliant object.

12. An apparatus according to claim 10;

further including a demodulator connected to the receiver for demodulating the modulated probing signal and outputting a demodulated probing signal to the processor.

13. An apparatus according to claim 10;

wherein the first signal generator generates a dual frequency acoustic signal.

14. An apparatus according to claim 13;

wherein the second signal generator generates an RF probing signal.

15. An apparatus according to claim 10;

wherein the second signal generator generates an RF probing signal.

16. An apparatus according to claim 10;

wherein the second signal generator generates a ground penetrating RADAR probing signal.

17. An apparatus according to claim 16;

wherein the first signal generator generates a dual frequency acoustic signal.

18. A method of detecting buried compliant objects, comprising the steps:

directing an acoustic signal toward a buried compliant object to excite the object to vibrate;

directing a probing signal toward the vibrating buried compliant object to cause the probing signal to be modulated and reflected by the vibrating object; and

processing the modulated, reflected probing signal to determine therefrom the presence of the buried compliant object.

19. A method according to claim 18;

wherein the acoustic signal comprises a dual frequency acoustic signal.

20. A method according to claim 19;

wherein the probing signal comprises an RF probing signal.

21. A method according to claim 18;

wherein the probing signal comprises an RF probing signal.

22. A method according to claim 18;

wherein the probing signal comprises a ground penetrating RADAR probing signal.

23. A method according to claim 22;

wherein the acoustic signal comprises a dual frequency acoustic signal.