Device For Detecting Location Of A Movable Body

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.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a device for detecting the location of a moving body.

2. Description of the Prior Art

Recently extreme effort has been exercised for the realization of automatic operation of a movable body such as a train, automobile, crane, truck, or the like, which is operated on the railway, highway, or in a factory, warehouse, or the like.

In the study of the automatic operation of a train, procedures have been sought for eliminating the hazards accompanying the high-speed operation of the train under a closely packed schedule, realizing highly efficient operation under the control of an electronic computer, and improving the operational economy through the econimization in manpower. In the study of automatic highway operation, the automatic control of car intervals, outruns, or steerings, and the safe and effective utilization of highways have been considered. Also, solutions have been sought for the automatic operation of a crane, truck, or a cargo-handling machine in a harbor (such as a stacker, reclaimer, loader, unloader, or the like). Not only the labor savings on the side of these machines, but also the labor economization under the computer controlled on-line real time operation or under direct coupling with the warehouse control system have been studied.

When it is desired to control a moving body from a control station on the ground, the following data transmission lines are theoretically required.

(1) A line for detecting the location of the moving body.

(2) A line for exchanging the data between the moving body and the stationary station on the ground.

This invention relates to the former line and associated devices thereto.

Heretofore, various devices for detecting the location of a moving body have been proposed. Typical prior art devices utilize switch and markers as shown in FIG. 1 which will be described hereinafter in more detail. In such a device, an electric pulse signal is generated from the switch in response to the moving body passing over the markers distributed along the track of the moving body.

However, such a device requires a separate line to transmit the electric signal to the stationary station on the ground, and if it is intended to install the switches on the ground instead of on the moving body and a marker on the moving body instead of on the ground, the installation cost will be further increased because of the numerous switches required.

Another example of prior art devices are those which utilize the rotation of a wheel on the moving body. That is, a pulse generator is installed on the moving body for rendering an electric pulse signal for every revolution of the wheel. However, this type of device also requires a separate line to transmit the electric signal to a stationary station on the ground if it is desired to supervise the location of the moving body from the stationary station on the ground. Furthermore, this type of device has another drawback of the error due to wear of the wheel or slip of the wheel, and the determination of the location for a long distance is thereby made impossible.

SUMMARY OF THE INVENTION

Therefore, a primary object of the present invention is to provide a device for detecting the location of a moving body, wherein the above described drawbacks of the conventional devices can be substantially eliminated.

Another object of the invention is to provide a device for detecting the location of a moving body, which includes a locating unit disposed on the ground whereby the location of the moving body can be determined with high precision without errors due to the wear of the wheel or slip thereof.

Still another object of the invention is to provide a device for detecting the location of a moving body, whereby the location can be detected either on the moving body or on the ground without requiring any additional equipment.

A further object of the invention is to provide a device for detecting the location of a moving body, wherein a locating unit disposed on the ground can also be employed for the purpose of data transmission.

An additional object of the present invention is to provide a device for locating a moving body, wherein the interference noise introduced from outside can be substantially eliminated.

These and other objects of the present invention can be achieved by a device for detecting the location of a moving body, comprising an antenna provided on the moving body. A fundamental and a plurality of other conductive 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 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 the binary system. A ground station is coupled with all of the conductor pairs, whereby the location of the moving body in any coded region can be detected by a conventional binary decoder at the ground station when an electric signal is transmitted from the antenna.

In another aspect, the objects can also be achieved by another device for detecting the location of a moving body, comprising an antenna 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 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 the binary system. A ground station is coupled to all of the conductor pairs, whereby the location of the moving body in whatever coded region can be detected on the moving body through the antenna by conventional frequency discriminator and binary decoder means when signals having different frequencies are supplied from the ground station to the conductor pairs.

In still another aspect of the invention, the objects can be achieved by a device for detecting the location of a moving body, which comprises a plurality of antennae of a completely isolated type located on the moving body. A fundamental and a plurality of other conductor pairs are constructed in the similar manner as described above, so that any region along the length of the path is coded in accordance with a binary code. A ground station is coupled to all of the conductor pairs, whereby when an electric signal is applied to all of said conductor pairs, the location of the moving body can be detected on the moving body through conventional binary decoders and the plurality of antennae receiving coded signals corresponding to the located region of the moving body.

The nature, principle, and the utility of the present invention can be better understood from the following detailed description of the invention when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view, in schematic form, of a conventional device for detecting the location of a moving body wherein a switch and markers consisting of iron pieces are employed.

FIG. 2 is a schematic diagram showing the basic construction of a system for detecting the location of a moving body according to the present invention; and

FIG. 3 is a diagram showing the variation of the output levels obtained from the system for detecting the location of a moving body shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a locating device of a moving body employing a switch and markers. A moving body 1 running along a railway bears a switch 2 which generates an electric pulse each time when the switch 2 is brought into the vicinity of each of the markers 3 consisting of an iron piece. However, when the electric signal generated by the switch 2 is to be detected at a station on the ground, a separate line is required to transmit the signal from the moving body 1 to a station on the ground (not shown). Thus the installation cost of locating the moving body is very high.

FIG. 2 shows the basic system for locating a moving body in accordance with the present invention. A number of pairs of conductors 14.sub.1, 14.sub.2, 14.sub.3 -- are used, each consisting of a pair of conductors transposed between each other at a predetermined interval. Each of the conductor pairs 14.sub.1, 14.sub.2, 14.sub.3 -- corresponds to one unit position in the binary system. That is, the repetition periods of the conductor pair 14.sub.i and the conductor pair 14.sub.i.sup.+1 are in a ratio of 2:1, and one complete period of 14.sub.i can be included in the one-half period of the 14.sub.i.sup.+1. In the drawing, antennae 15.sub.1, 15.sub.2, 15.sub.3 -- are shown mounted on the moving body (not shown). A receiving station 16 is located on the ground.

When the pairs of the conductors 14.sub.1, 14.sub.2, -- 14.sub.i are extended in alignment along the path of the moving body and a single electric signal is commonly emitted from the antennae 15.sub.1, 15.sub.2, -- 15.sub.i, -- while the moving body moves along the path, the signal levels received along the conductor pairs 14.sub.1, 14.sub.2, -- at the ground station 16 are varied as shown in FIG. 3.

In FIG. 3, 16.sub.1, 16.sub.2, -- indicate the signal levels received at the ground station 16 along the conductor pairs 14.sub.1, 14.sub.2, -- respectively. If it is assumed that, for instance, a portion producing a signal such as the region 17.sub.1 or 17.sub.3 along the signal level 16.sub.1 corresponds to "0" of a binary system and another portion 17.sub.2 producing no signal corresponds to "1" of the binary system, any region along the conductor pair 14.sub.1 can be identified by "0" or "1." The same condition is applied for the conductor pairs 14.sub.2, 14.sub.3, --, so that any region along the path of the moving body can be identified by a combination of binary codes such as (0, 0, 0) which corresponds to the region 17.sub.1. Likewise, the region 17.sub.2 can be identified by the combination of binary codes (0, 0, 1), and the region 17.sub.3 can be identified by the binary codes (0, 1, 0). From these relations, the location in whatever region of the moving body along the path can be easily identified at the ground station from the received signal levels along the conductor pairs.

In the arrangement shown in FIG. 2, the reason the conductor pairs are transposed as described above is that the two consecutive portions producing a signal level (broadly spaced apart portions) along a conductor pair are thereby rendered to produce a signals of different polarity, i.e., a 180 degree phase difference so that the mutual interference between any two conductor pairs is thereby minimized and the independent nature of each conductor pair is assured.

In the above description, a signal is emitted from the antennae on the moving body, and the location of the moving body has been detected at the ground station.

However, in another aspect of the present invention, the location of the moving body can be detected on the moving body itself. In that case, each of the conductor pairs 14.sub.1, 14.sub.2, -- may be applied with different signals having different frequencies, and the outputs therefrom may be received by one antenna provided on the moving body. The outputs thus received are thereafter divided into different frequency components and the binary codes designating the location of the moving body can be obtained as described above.

Alternatively, the same signal may be applied to the conductor pairs 14.sub.1, 14.sub.2, -- from the ground station, and the output signals transmitted along the conductor pairs may be received through a plurality of antennae provided on the moving body so that the above described coded region can be detected on the moving body. In this case, the antennae must be so arranged that each antenna is coupled with each of the conductor pairs and the cross-coupling therebetween should be minimized.

In the above description, although the amplitude of the signals is used to determine location, it is of course possible to employ a phase shifting technique in the arrangement of the present invention. In that case, however, two more parallel lines must be installed along the above described conductor pairs so that a reference phase signal is thereby obtained.

Although in the above description and in FIG. 2, a plurality of antennae have been used on the moving body, it will be apparent to the skilled in the art that a single antenna may be substituted for the plurality of antennae when a single electric signal is emitted or received commonly through the plurality of antennae.

While the invention has been particularly shown and described with reference to the preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims

We claim:

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.