Process and apparatus for geotechnic exploration

• US 4,381,544 A
• Filed: 11/07/1980
• Issued: 04/26/1983
• Est. Priority Date: 11/07/1980
• Status: Expired due to Term

• Current Assignee: Era Aviation, Inc. (Ravn Air Group, Inc.)
• Original Assignee: Energy Northwest
• Inventors: Stamm, Michael E.
• Primary Examiner(s): Wise, Edward J.
• Application Number:
  US06/204,781
• Time in Patent Office: 900 Days
• Field of Search: 324/330, 324/337, 364/420, 364/515
• US Class Current: 702/2
• 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 13/89 for mapping or imaging
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: G01V 3/17 operating with electromagnetic waves operating with millimetre waves G01V8/005

Abstract

A process for geotechnic exploration comprising the steps of:

(a) Emitting one or more brief electromagnetic pulses or waves from an airborne platform at regular intervals based on the airspeed of the platform and the area being surveyed;

(b) The wavelengths, frequencies and cyclicity of the waves being selected to provide, upon reflection, satisfactory indicia of the physical characteristics of the area being measured;

(c) Receiving the reflections of said waves at said platform;

(d) Amplifying said reflected waves to a readily processable level;

(e) Processing said waves to enhance the spatial resolution of images produced therefrom;

(f) Further processing said waves by selecting those variables represented by the waves that are deemed relevant;

(g) Displaying said waves in visual form representing a cross-section of an area;

(h) If desired, storing in recoverable form the signals representing said variables; and

(i) Repeating said process as often as desired.

The invention includes the aircraft-mounted radar apparatus for performing the process.

Claims

1. A process for geotechnic exploration comprising the steps of:

(a) Emitting at least three electromagnetic pulses toward the ground from an airborne platform at regular intervals, based on the airspeed of the platform and the area being surveyed the wavelengths, frequencies, cyclicity and timing of the pulses being selected to provide, upon reflection, satisfactory indicia of the physical characteristics of the area being measured;

(b) Receiving the reflections of said pulses at said platform;

(c) Amplifying the reflected pulses to a readily processible level;

(d) Processing the reflected pulses to enhance the spatial resolution of images produced therefrom;

(e) Further processing the reflected pulses by selecting those variables represented by the pulses that are deemed relevant;

(f) Displaying the reflected pulses in visual form representing a cross-section of an area;

(g) If desired, storing in recoverable form the pulses representing said variables; and

(h) Repeating said process as often as desired.

2. A process as set forth in claim 1, wherein said three electromagnetic pulses have different frequencies in the range from about 100 mHz to about 1500 mHz.

3. A process as set forth in claim 1, wherein said pulses are single cycle pulses, the duration of each pulse is in the range from about one to about five nanoseconds.

4. A process as set forth in claim 1, wherein said pulses are single cycle pulses, having respective frequencies in the range from about 100 mHz to about 1500 mHz and of duration in the range from about one to about five nanoseconds.

5. A process as set forth in claim 1, including the step of color-coding said visual image and correcting for geometric distortion to produce an easily read color-coded picture of a section of the earth being surveyed.

6. Apparatus for airborne geotechnic exploration, comprising:

(a) Antenna means adapted to produce short microwave pulses in the range from about 100 mHz to about 1500 mHz;

(b) Antenna means adapted to receive microwave pulses in the range from about 100 mHz to about 1500 mHz; and

(c) Means to produce a visual output representing a cross-section of the earth'"'"'s sub-surface exposed to said microwave pulses.

7. Apparatus as set forth in claim 6, wherein said two antennae means comprises a single transverse electric mode horn antenna.

8. Apparatus as set forth in claim 6, wherein said antenna means produces single cycle microwave pulses in the range from about 100 mHz to about 1500 mHz and of duration in the range from about one to about five nanoseconds.

9. Apparatus as set forth in claim 6, wherein said last-named means includes means to geometrically correct the visual output and to color code the output.

10. Apparatus as set forth in claim 6, including means to measure and relate the linear position of the antenna means to the visual output produced.