DEVICE FOR DETECTING LOCATION OF A MOVABLE BODY

• US 3,786,411 A
• Filed: 11/26/1971
• Issued: 01/15/1974
• Est. Priority Date: 11/26/1970
• Status: Expired due to Term

• Current Assignee: Kenichi Yoshida, Masaki Ohmori, Noritaka Kurauchi, Susumu Hiraoka
• Original Assignee: Kenichi Yoshida, Masaki Ohmori, Noritaka Kurauchi, Susumu Hiraoka
• Inventors: Yoshida, Kenichi, Kurauchi, Noritaka, Hiraoka, Susumu, Ohmori, Masaki
• Primary Examiner(s): Borchelt, Benjamin A.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US05/202,337
• Time in Patent Office: 781 Days
• Field of Search: 246/167R,122R,167D 179/82 340/47,38L,23
• US Class Current: 340/988
• CPC Class Codes: B61L 25/02 Indicating or recording positions or identities of vehicles or trains
• CPC Class Codes: B61L 25/025 Absolute localisation, e.g. providing geodetic coordinates

Abstract

A device for detecting the location of a moving body comprising an antenna or antennae provided on the moving body. A fundamental and a plurality of other conductor pairs extend in parallel along the path of the moving body. Each of the conductor pairs includes portions in which the coupling between the conductor pair and the antenna is changed periodically. The changing period of any one of the other conductor pairs is selected as an integer fraction of the changing period of the fundamental conductor pair, so that any region along the length of the path is coded in accordance with a binary code. A ground station is coupled with all of the conductor pairs, whereby the location of the moving body in whatever coded region can be detected from the ground station or the moving body when an electric signal is transmitted from the antenna, or when one or a plurality of signals are supplied from the ground station to the conductor pairs.

Claims

1. A system for detecting the location of a movable body, which body may be either moving or stationary at the time of location detection, comprising:

a. a fundamental conductor pair extending along the path of said movable body;

b. a plurality of other conductor pairs extending along the path of said movable body in parallel with said fundamental conductor pair;

c. antenna means mounted on said movable body, said antenna means being electrically coupled to all of said conductor pairs wherein the coupling between said antenna means and each of said Conductor pairs is changed periodically along the path of said movable body and the period of change for each conductor pair is a negative integer power of two of the period of said fundamental conductor pair according to a specific parallel binary code corresponding to a region along the path of said movable body, whereby the specific parallel binary code is detected in accordance with the coupling between said antenna means and all of said conductor pairs; and

d. ground station means coupled to all of said conductor pairs.

2. The system as set forth in claim 1 wherein said antenna means transmits a signal to all of said conductor pairs and said ground station means receives the signal transmitted by said conductor pairs and thereby produces a signal indicative of the location of said moving body.

3. The system as set forth in claim 1 wherein said ground station means transmits a signal over each of said conductor pairs wherein the signal transmitted over each conductor pair is of a different frequency and wherein said antenna means receives all of said signals and thereby produces a signal in said moving body indicative of the location of said moving body along said path.

4. The system as set forth in claim 1 wherein said ground station means transmits a signal over each of said conductor pairs and wherein said antenna means includes a plurality of antennae each of said antennae corresponding to one of said conductor pairs and each of said antennae being electrically isolated from the others of said antennae and the non-corresponding conductor pairs, wherein a signal is produced in said moving body indicative of the location of said moving body along said path.

5. The system as set forth in claim 1 wherein the periodic change in said conductor pair is in the ratio of 2:

1 with the periodic change in the preceding conductor pair.