Ground penetrating radar array and timing circuit

• US 6,496,137 B1
• Filed: 09/08/2000
• Issued: 12/17/2002
• Est. Priority Date: 09/19/1999
• Status: Active Grant

• Current Assignee: Mal GeoScience AB
• Original Assignee: Mal GeoScience AB
• Inventors: Johansson, Bernth A. T.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US09/658,061
• Time in Patent Office: 830 Days
• Field of Search: 342/22, 342/73, 342/82, 342/83, 342/85, 342/88, 342/89, 342/90, 342/94, 342/98, 342/102, 342/114, 342/115
• 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: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005

Abstract

Methods and systems consistent with this invention identify a buried object using array-based ground penetrating radar having a control device, a plurality of transmit antennas, and a plurality of receive antennas. Such methods and systems receive a transmit timing input signal and a receive timing input signal. Such methods and systems comprise a first delay circuit for receiving the transmit timing input signal and generating a number of intermediate transmit timing signals delayed with respect to each other by a delay time, and transmit output switch circuit to select either the transmit timing input signal or a corresponding one of the intermediate transmit timing signals as a corresponding output transmit timing signal. Such methods and systems also comprise a second delay circuit for receiving the receive timing input signal and generating a number of intermediate receive timing signals delayed with respect to each other by the delay time, a shift-delay circuit coupled to the second delay circuit and the receive timing input signal to add the delay time to the intermediate receive timing signals, and a receive output switch circuit to select either the receive timing input signal or a corresponding one of the intermediate receive timing signals as a corresponding output receive timing signal. Such methods and systems also comprise an antenna array comprising a plurality of transmit antennas, a plurality of receive antennas, and means for selectively enabling the transmit and receive antennas to allow each of the receive antennas to receive energy from any one of the transmit antennas.

Claims

1. An apparatus for identifying a buried object using array-based ground penetrating radar having a control device, a plurality of transmit antennas, and a plurality of receive antennas, said control device receiving a transmit timing input signal and a receive timing input signal, said apparatus comprising:

a first delay circuit receiving the transmit timing input signal and generating a number of intermediate transmit timing signals delayed with respect to each other by a delay time;

transmit output switch circuit to select either the transmit timing input signal or a corresponding one of the intermediate transmit timing signals as a corresponding output transmit timing signal;

a second delay circuit receiving the receive timing input signal and generating a number of intermediate receive timing signals delayed with respect to each other by the delay time;

a shift-delay circuit coupled to the second delay circuit and the receive timing input signal to add the delay time to the intermediate receive timing signals; and

receive output switch circuit to select either the receive timing input signal or a corresponding one of the intermediate receive timing signals as a corresponding output receive timing signal.

2. The apparatus of claim 1, further comprising:

an element to trigger one of the plurality of transmit antennas to transmit dependent on the output transmit timing signal; and

an element to trigger one of the plurality of receive antennas to sample a received waveform dependent on the output receive timing signal.

3. The apparatus of claim 2, further comprising a monostatic data acquisition controller.

4. The apparatus of claim 1, further comprising

a first comparator wherein the transmit timing input signal is derived by comparing a common timing signal to a transmit threshold signal, and

a second comparator wherein the receive timing input signal is derived by comparing the common timing signal to a receive threshold signal.

5. The apparatus of claim 1, wherein the first delay circuit comprises a first plurality delay elements, the second delay circuit comprises a second plurality of delay elements, and the shift-delay circuit comprises a shift-delay element.

6. The apparatus of claim 5, wherein all the delay elements are of the same value.

7. The apparatus of claim 1, wherein the apparatus further comprises a mobile housing for moving the apparatus along terrain under which the object is buried.

8. A method for identifying a buried object using array-based ground penetrating radar having a control device, a plurality of transmit antennas, and a plurality of receive antennas, said control device receiving a transmit timing input signal and a receive timing input signal, the method comprising:

generating a plurality of intermediate transmit timing signals by delaying the transmit timing input signal by a plurality of delay times;

selecting either the transmit timing input signal or a corresponding one of the intermediate transmit timing signals as a corresponding output transmit timing signal;

generating a number of intermediate receive timing signals by delaying the receive timing input signal by the plurality of delay times; and

selecting either the receive timing input signal or a corresponding one of the intermediate receive timing signals as a corresponding output receive timing signal.

9. The method of claim 8, further comprising adding a second delay time to the intermediate receive timing signals.

10. The method of claim 8, further comprising

triggering one of the plurality of transmit antennas to transmit dependent on the output transmit timing signal; and

triggering one of the plurality of receive antennas to sample a received waveform dependent on the output receive timing signal.

11. The method of claim 10, further comprising acquiring data with a monostatic data acquisition controller.

12. The method of claim 8, further comprising

comparing a common timing signal to a transmit threshold signal to derive the transmit timing input signal;

and

comparing the common timing signal to a receive threshold signal to derive the receive timing input signal.

13. An apparatus for identifying a buried object using array-based ground penetrating radar having an antenna array, said antenna array comprising:

a plurality of transmit antennas,

a plurality of receive antennas transmitting digital data to a control unit simultaneously and

means for selectively enabling the transmit and receive antennas to allow each of the receive antennas to receive energy from any one of the transmit antennas.

14. The apparatus of claim 13, wherein a plurality of the transmit antenna each have an impulse generator and a high-voltage generator.

15. The apparatus of claim 13, wherein a plurality of the receive antennas each have a sample and hold amplifier and an analog to digital converter.

16. The apparatus of claim 13, wherein two positioning devices are used to determine a direction of movement.

17. A control device for an impulse radar having a plurality of transmit antennas and a plurality of receive antennas, said control device receiving a transmit timing input signal and a receive timing input signal, comprising:

a first delay circuit receiving the transmit timing input signal and generating a number of intermediate transmit timing signals delayed with respect to each other by a delay time;

transmit output switch circuit to select either the transmit timing input signal or a corresponding one of the intermediate transmit timing signals as a corresponding output transmit timing signal;

a second delay circuit receiving the receive timing input signal and generating a number of intermediate receive timing signals delayed with respect to each other by the delay time;

a shift-delay circuit coupled to the second delay circuit and the receive timing input signal to add the delay time to the intermediate receive timing signals; and

receive output switch circuit to select either the receive timing input signal or a corresponding one of the intermediate receive timing signals as a corresponding output receive timing signal.

18. The control device of claim 17, further comprising

an element to trigger one of the plurality of transmit antennas to transmit dependent on the output transmit timing signal; and

an element to trigger one of the plurality of receive antennas to sample a received waveform dependent on the output receive timing signal.

19. The control device of claim 18, further comprising a monostatic data acquisition controller.

20. The control device of claim 17, further comprising

a first comparator wherein the transmit timing input signal is derived by comparing a common timing signal to a transmit threshold signal, and

a second comparator wherein the receive timing input signal is derived by comparing the common timing signal to a receive threshold signal.

21. The common device of claim 17, wherein the first delay circuit comprises a first plurality delay elements, the second delay circuit comprises a second plurality of delay elements, and the shift-delay circuit comprises a shift-delay element.

22. The control device of claim 21, wherein all the delay elements are of the same value.

23. The control device of claim 17, wherein the control device further comprises a mobile housing for moving the control device along terrain under which the object is buried.

24. An apparatus for identifying a buried object using array-based ground penetrating radar having a control device, a plurality of transmit antennas, and a plurality of receive antennas, said control device receiving a transmit timing input signal and a receive timing input signal, the apparatus comprising:

means for generating a plurality of intermediate transmit timing signals by delaying the transmit timing input signal by a plurality of delay times;

means for selecting either the transmit timing input signal or a corresponding one of the intermediate transmit timing signals as a corresponding output transmit timing signal;

means for generating a number of intermediate receive timing signals by delaying the receive timing input signal by the plurality of delay times; and

means for selecting either the receive timing input signal or a corresponding one of the intermediate receive timing signals as a corresponding output receive timing signal.

25. The apparatus of claim 24, further comprising means for adding a second delay time to the intermediate receive timing signals.

26. The apparatus of claim 24, further comprising

means for triggering one of the plurality of transmit antennas to transmit dependent on the output transmit timing signal; and

means for triggering one of the plurality of receive antennas to sample a received waveform dependent on the output receive timing signal.

27. The apparatus of claim 26, further comprising means for acquiring data with a monostatic data acquisition controller.

28. The apparatus of claim 26, further comprising

means for comparing a common timing signal to a transmit threshold signal to derive the transmit timing input signal;

and

means for comparing the common timing signal to a receive threshold signal to derive the receive timing input signal.

29. The apparatus of claim 24, wherein the first delay circuit comprises a first plurality delay elements, the second delay circuit comprises a second plurality of delay elements, and the shift-delay circuit comprises a shift-delay element.

30. The apparatus of claim 27, wherein all the delay elements are of the same value.

31. The apparatus of claim 24, wherein the apparatus further comprises a mobile housing for moving the apparatus along terrain under which the object is buried.