Subsurface target identification radar

• US 5,130,711 A
• Filed: 12/02/1991
• Issued: 07/14/1992
• Est. Priority Date: 12/02/1991
• Status: Expired due to Fees

• Current Assignee: Mitsui Engineering & Shipbuilding Company Limited (Mitsui E&S Holdings Co., Ltd.)
• Original Assignee: Mitsui Engineering & Shipbuilding Company Limited (Mitsui E&S Holdings Co., Ltd.)
• Inventors: Jyomuta, Chihiro, Kimura, Noriaki, Murasawa, Kanji, Konishi, Masuo
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US07/801,445
• Time in Patent Office: 225 Days
• Field of Search: 342/22, 342/27, 342/74, 342/82, 342/89, 342/85
• 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 7/024 using polarisation effects in waveguides H01P1/165; for aerials H01Q, e.g. H01Q15/22, H01Q15/24, H01Q19/195
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence
• CPC Class Codes: H01Q 21/245 provided with means for varying the polarisation polarising devices H01Q15/24; tracking by comparing linear polarisation compounds G01S3/146; reducing depolarisation effects H04B7/00; polarisation diversity H04B7/10

Abstract

Subsurface target identification radar includes an antenna array, a rotary encoder, a radar controller, a polarization switching circuit, and transmitter and receiver circuits. The antenna array is constituted by dipole antennas having plane triangle elements. The antennas are disposed at angular intervals of 120° with respect to a rotated symmetric point of the array. The rotary encoder generates a distance pulse every time the radar travels a presetted distance. The radar controller sequentially generates three switching pulses within one period on the basis of the distance pulse from the rotary encoder. The polarization switching circuit selects an arbitrary dipole antenna as a transmitting antenna from the antenna array, selects an arbitrary dipole antenna, other than the selected antenna, as a receiving antenna, and changes a combination of selected antennas every time the switching pulse is generated by the radar controller. The transmitter and receiver circuits transmit/receive electromagnetic waves through the selected antennas.

Claims

1. An underground object search radar, comprising:

an antenna array constituted by dipole antennas having plane triangle elements, each of said antennas being disposed at angular intervals of 120°

with respect to a rotated symmetric point of the array;

a rotary encoder for generating a distance pulse every time said radar travels a presetted distance;

a radar controller for sequentially generating three switching pulses within one period on the basis of the distance pulse from said rotary encoder;

a polarization switching circuit for selecting an arbitrary dipole antenna as a transmitting antenna from said antenna array, selecting an arbitrary dipole antenna, other than said selected antenna, as a receiving antenna, and changing a combination of selected antennas every time the switching pulse is generated by said radar controller; and

transmitter and receiver circuits for transmitting/receiving electromagnetic waves through said selected antennas

2. A radar according to claim 1, wherein said polarization switching circuit selects two of said three dipole antennas as a receiving antenna and a transmitting antenna, respectively, and switching the receiving and transmitting antennas in a presetted order every time the switching pulse is generated.