Highway Speed Ground Penetrating Radar System Utilizing Air-Launched Antenna and Method of Use

• US 20110115666A1
• Filed: 11/17/2009
• Published: 05/19/2011
• Est. Priority Date: 11/17/2009
• Status: Active Grant

• Current Assignee: Geophysical Survey Systems, Inc.
• Original Assignee: Geophysical Survey Systems, Inc.
• Inventors: Feigin, Jeffrey R., Schutz, Alan E.
• Granted Patent: US 8,115,667 B2
• Time in Patent Office: Days
• US Class Current: 342/22
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/40 Means for monitoring or calibrating

Abstract

Embodiments of the disclosed technology comprise an air-launched antenna system with interference-rejection technology that operates in analog hardware as well as by way of a digital filtering technique. Using an inline analog hardware filter combined with a digital filter, to determine transversal (and/or recursive) coefficients, in a calibration phase, a measurement system may be configured to remove interference and the effects (such as a delay or temperature variation) which result from use of an analog filter. In this manner, the resulting measurements of a composition of road surface are more accurate and useful.

Claims

1. A ground penetrating radar system comprising:

an air-launched transmitter and receiver;

an inline analog interference rejection filter;

an analog to digital converter;

a delay-tap filter;

a measurement system for determining the composition of a heterogeneous material.

2. The ground-penetrating radar system of claim 1, wherein said inline analog interference rejection filter comprises an analog filter.

3. The ground penetrating radar system of claim 2, wherein said delay-tap filter mitigates group delay distortion effects caused by said analog filter.

4. The ground penetrating radar system of claim 3, wherein said analog filter comprises one or a plurality of filters, each said one or a plurality of filters capable of operation on a designated subset of frequencies.

5. The ground penetrating radar system of claim 4, wherein a frequency range of filtering of said one or a plurality of analog filters is determined based on anticipated interference.

6. The ground-penetrating radar system of claim 4, wherein a frequency range of filtering of said one or a plurality of analog filters is determined based on actual interference.

7. The ground penetrating radar system of claim 1, wherein said air-launched transceiver is mounted on a vehicle at least one tenth of an inch above said heterogeneous material.

8. A method for calibrating a ground penetrating radar system comprising:

using an air-launched transceiver to reflect an ultra-wide band signal off a homogeneous material;

using an inline analog rejection filter to block a selection of frequencies in a reflected said signal based on anticipated interference from external signals;

shaping said reflected signal with a digital filter to at least partially restore said ultra-wide band signal; and

using transversal coefficients determined in said prior step of shaping to shape a reflection of an ultra-wide band signal off a heterogeneous material.

9. The method of claim 8, wherein said homogeneous material is a metal plate.

10. The method of claim 8, wherein said heterogeneous material is a road surface.

11. The method of claim 10, wherein said air-launched transceiver is positioned at least six inches from said road surface during said shaping of said signal reflected off said road surface.

12. The method of claim 8, wherein said inline analog interference rejection filter comprises an analog filter and said digital filter mitigates group delay distortion effects caused by said analog filter.

13. The method of claim 12, wherein said analog filter comprises one or a plurality of filters, each said one or a plurality of filters capable of operation on a designated subset of frequencies.

14. The method of claim 8, wherein said transversal coefficients vary based on temperature.

15. A ground penetrating radar measurement device comprising:

means for transmitting and receiving a radio signal;

analog filtering means;

digital filtering means;

means for determining transversal co-efficients associated with said digital filter to at least partially restore said transmitted radio signal;

means for measuring a composition of a heterogeneous material.

16. The ground penetrating radar measurement device of claim 15, wherein said means for transmitting and receiving said radio signal comprises an antenna situated at least one tenth of an inch above said heterogeneous material.

17. The ground penetrating radar measurement device of claim 15, wherein said antenna is mounted on a vehicle traveling at speeds above 10 miles per hour.

18. The ground penetrating radar measurement device of claim 15, wherein said composition is measured to a resolution of at least one inch.

19. The ground penetrating radar measurement device of claim 16, wherein said resolution is more precise as a result of use of said digital filter.

20. The ground penetrating radar measurement device of claim 15, wherein said digital filtering means are calibrated based on a measured reflection of said radio signal, and said reflection is a reflection off a homogeneous material.

21. The ground penetrating radar measurement device of claim 15, wherein said digital filtering means are further calibrated based on a cost function.