Apparatus for detecting materials buried under the ground

• US 4,951,055 A
• Filed: 05/15/1989
• Issued: 08/21/1990
• Est. Priority Date: 11/17/1986
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Komatsu Seisakusho
• Original Assignee: Kabushiki Kaisha Komatsu Seisakusho
• Inventors: Katayama, Yukinori
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Hellner, Mark
• Application Number:
  US07/378,518
• Time in Patent Office: 463 Days
• Field of Search: 342/22, 324/329, 324/337, 324/326
• 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 7/295 Means for transforming co-ordinates or for evaluating data, e.g. using computers
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005

Abstract

If electromagnetic waves are emitted from a plurality of points on the ground surface above a material (TG) buried under the ground, an echo image (EP) formed from the data of propagation times of reflected waves at each of the points describes a hyperbola as a result of expansion of the transmitted electromagnetic waves. An operation is carried out to overlap on the echo image (EP) a false echo image (DM) which lies on the same coordinate system and which consists of a similar hyperbolic image. If the two echo images (DM, EP) are overlapped upon each other as the result, the vertex position and the expansion of the opening of the echo image (EP) can be determined from the data of the false echo image (DM). The propagation velocity of electromagnetic waves under the ground is then calculated from the data that represents the vertex position and the expansion of the opening. After the propagation velocity of the electromagnetic waves are calculated, the position of the material (TG) under the ground is then calculated in relation to the data of propagation time at any position.

Claims

1. A buried-object detecting apparatus which emits electromagnetic waves from a transmitter mounted on a mobile vehicle toward the ground, receives waves reflected on an object buried under the ground at a receiver mounted on said mobile vehicle and detects a position of said buried object on the basis of a propagation time of said reflected waves;

characterized by comprising;

means for displaying echo images of the buried object with parameters of a depth direction of the buried material and a movement direction of the mobile vehicle;

first means, on the basis of said propagation time of the reflected waves obtained when the mobile vehicle is moved by a predetermined distance while emitting electromagnetic waves from said transmitter mounted on the mobile vehicle, for forming a hyperbolic echo image and causing said hyperbolic echo image to be displayed on said display means;

second means for forming a hyperbolic false echo image having as a parameter a coefficient for converting underground propagation speed of the electromagnetic wave to distance information and for causing said false echo image to be displayed on the display means;

third means for obtaining a vertex position of said false echo image based on an operation for moving display position of said false echo image in which operation the vertex position of said false echo image is caused to be coincided with a vertex position of said echo image of buried object;

fourth means for obtaining said coefficient for converting the underground propagation speed into the distance information based on an operation for changing display modes of the false echo image in which operation an expansion of opening of said false echo image is caused to be overlapped with that of said echo image of the buried object; and

fifth means for obtaining the position of said buried object by correcting the coordinates of the vertex position of said false echo image obtained by said third means with the use of the coefficient obtained by the fourth means.

2. A buried-object detecting apparatus as set forth in claim 1, wherein said first means includes means for subjecting a demodulation signal of a received signal of said reflected waves to a logarithmic conversion to display on said display means an echo image corresponding to said demodulation subjected to the logarithmic conversion.

3. A buried-object detecting apparatus as set forth in claim 1, wherein said first means includes means for subjecting a demodulation signal of a received signal of said reflected waves to a differentiating operation to display on said display means an echo image corresponding to said demodulation subjected to the differentiating operation.