System for detecting underground objects

• US 4,831,383 A
• Filed: 03/10/1988
• Issued: 05/16/1989
• Est. Priority Date: 03/11/1987
• Status: Expired due to Fees

• Current Assignee: Korea Electric Power Corporation (Government of South Korea), Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Korea Electric Power Corporation (Government of South Korea), Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Maeda, Kouji, Usami, Teruo, Ohnishi, Hiroyasu, Jitumori, Akio, Uekubo, Yasuhiro, Matsuura, Tatsukichi
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Barron, Jr., Gilberto
• Application Number:
  US07/166,472
• Time in Patent Office: 432 Days
• Field of Search: 342/25, 342/22
• 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: G01S 13/9027 Pattern recognition for feature extraction
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005

Abstract

A system for detecting underground objects is disclosed wherein image data obtained through a deep range-migration correction and image data obtained through a shallow range-migration correction are combined so that data at the corresponding positions on both the image data at high level may mutually intensify, whereas other data may mutually weaken. The target spot on the thus combined image data is made sharp and provides sufficently high resolution.

Claims

1. In a system for detecting an underground target provided with a transmitting antenna and a receiving antenna disposed at a predetermined mutual distance and adapted such that both said antennas are moved in increments of a predetermined distance on the ground in a direction virtually at right angles with the direciton in which the antennas are disposed, a pulse signal is emitted from said transmitting antenna into soil at every increment in the movement and the reflected wave is received by said receiving antenna, reflected wave profile data on a plane cutting through the soil at right angles with the ground is obtained and the data is subjected to synthetic aperture processing, whereby a detected image output of the target buried under the ground is obtained, said system for detecting an underground target comprising the steps of:

making range migration corrections in said synthetic aperture processing such that both a deep range-migration correction with range bins of a number virtually corresponding to the synthetic aperture and a shallow range-migration correction with range bins of a number virtually corresponding to the pulse width of said pulse signal are performed; and

combining both the image data obtained in said range migration corrections, whereby a detected image output of said target is provided.

2. A system for detecting an underground target according to claim 1, wherein a geological correction is executed prior to said synthetic aperture processing whereby reflected wave profile data in which a time scale is converted to a length scale is obtained.

3. A system for detecting an underground target according to claim 1, wherein a geological correction is executed posterior to said synthetic aperture processing whereby reflected wave profile data in which a time scale is converted to a length scale is obtained.