ES2277621T3 - PROCEDURE AND SYSTEM OF DETECTION OF OBJECTS THROUGH A VIA. - Google Patents

Abstract

To determine if a track section (1) is covered by a wagon or foreign object (6) detectors (D1-D5) are arranged as freely selectable intervals along the track. The detectors use an NMR principle with transmitted pulse packets detected by the detectors and response signals converted into the frequency domain using a Fourier transform. An object within range of a detector alters the magnetic field such that largely no response is generated. <??>After Fourier transformation of the response signals, the response signals are assigned to the detectors. Thus the absence of a response signal can be used to indicate the precise location of a possible obstacle on the track. <??>An Independent claim is also included for a corresponding system.

Description

Object detection system and procedure along a path.

The present invention relates to a procedure for the detection of objects along a path, made according to the preamble of claim 1.

The identification of whether a line section or a section of the track is occupied by a wagon, it can be done, for example, with the following means:

i)

The line sections are monitored with the so-called counters of axes Both at the entrance of a train in a line section and also when leaving the section in question, the axes are counted and in case of equality, a message will be made that this section of line is free.

ii)

Shorter sections of the road, as per For example, needles are specially protected with the so-called DC circuits, in which a lane is insulated electrically in front of another lane. Through the circulation in such sections, a current circuit is enclosed by the wheels of an axis and in this way a state of occupied.

The techniques mentioned above work in a safe way, however they are limited to the occupation of a section of the track by wagons and locomotives. A car, which, for example, is blocked at a level crossing, with the means mentioned above, cannot be detected. The procedures with the direct current circuits in the winter service, with the use of salt, are prone to breakdowns, for example in the area of the train stations or the level crossings of the salt water that is in the line has a relatively small resistance and between two rails it forms a flat electric conduction. This erroneous detection effect appears both in a direct current circuit, and also in the use of a signal of many khz. A repetition of a measurement within a few seconds does not provide any new information on the
situation.

In WO 98/58829 with the denomination "Vehicle Presence System" refers to a system in the which, along a railroad line in the stile of the track passive magnetic detectors are put on, to check occupancy of the track in the area of a level crossing. The detection results from a  comparison of signals, of those stored in case of absence of objects and signals that pick up a specific moment during detection and with signal storage. This "Vehicle Presence System" is truly very appropriate, without However, it is linked to a high cost in connection technology and is strongly limited in terms of the number of coils of induction usable.

US 5,868,360 also shows a procedure and a system for the detection of objects along of the tracks.

The present invention aims to propose an object detection procedure along the tracks, that can be done with a small expense in connection technology, which is independent of direct climatic influences and indirect and allowing control of a section, including the direct environment, with solutions in scale.

This objective is solved by means of measures proposed in claim 1. Other embodiments Advantageous of the invention are included in other claims.

For the solution according to the invention

`` the detectors work according to the Nuclear Magnetic Resonance (NMR) procedure and by the stages of process

TO

The response signals are detected in a pulse packet emitted at the detectors;

B

The response signals that are detected are transformed into a signal in the frequency space; ''

C

The response signal transformed in the frequency space, it compare with the response signals memorized previously, that were memorized when you are sure of the absence of an object according to the steps of procedure A and B, in which a Proven inequality is valued as the presence of a object;

a procedure is created that is independent of the climatic influences and in a way sign an acknowledgment of objects throughout and in the environment Immediate tracks. The method according to the invention is in this sense a static procedure, given the doubtful result of an examination of the pathways on the presence of objects you can repeat several times without an inspection of the place.

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This way the following can occur additional advantages:

i)

Dice that

the detectors are put in position along the railways in a sequence which can be freely chosen;

The procedure it can be optimally restricted to the places allegedly dangerous (claim 2).

ii)

Dice that

the detectors they are put in position along the railways;

It can install a system so that the procedure can be performed according to the invention and be monitored, without it being due interrupt the rail service (claim 3).

iii)

Given the

at the stage of procedure C the response signals transformed in space frequency can be associated with detectors;

It can locate exactly one object found by a detector and it you can direct an intervention detachement exactly to the place in question of the section of the railway track (claim 6).

iv)

Dice that

in the phase of procedure C a selection of response signals is memorized transformed into the frequency space, on a package of impulses emitted in a fixed reticulum depending on the weather;

by realization of the process according to the invention, it can recognize especially well a system change that appears slowly. So on the one hand it is possible that the signals of response stored at the beginning are corrected in space frequency through a statistical procedure and on the other hand  you can carry an exact logbook on the mentioned system status (claim 8).

The following explains in more detail the invention by way of example by means of the attached drawings, in those shown:

Figure 1a Line section equipped with detectors for performing the procedure according to the invention;

Figure 1b Assignment of signals according to transformation occurred in frequency space

Figure 2 Design of a detector;

Figure 3 Impulse package representation emitted, signal path through the gradient and signal coil of response.

Figure 1a shows an overview of a line section. Parallel to a track 1 are, at a distance of of the axis of track 2, the metal detectors D 1, D 2, .., placed at freely chosen intervals, .., D_ {34}, D_ {45}, .. (not fully represented or listed in the figure 1a). These intervals result from the requirements railway administration companies, for these intervals the typical magnitudes rises to 5 m .. 200 m, for the distance to the axis of the track from 3 to 6 m. The detectors of metals - hereinafter referred to as abbreviated detectors D_ {1}, D_ {2}, .., - are linked to an emission unit / of reception 5, in which a detector D_ {n} is the last detector seen geometrically. The index n marks the maximum index of detectors, in which the typical values for n are in the magnitude 10 .. 100.

Figure 2 shows the design of a detector D_ {1} that works according to the NMR procedure (Nuclear Magnetic Resonance), which contains permanent magnets 10, a coil of gradient 11 and a sending / receiving unit 14. The magnet permanent 10 has a horseshoe shape, in the air space it is placed a sample of water 12, which is surrounded both by the gradient coil 11 as well as the emission unit / of reception 14. It must be borne in mind that in construction it is necessary, that the orthogonal B field generated in the unit of emission / reception 14 is in field B of the permanent magnet 10. Water sample 12 consists of a glass frame that has been filled with distilled water, a typical interior cubic capacity (also called measuring capacity) of the glass frame is in the dimension of 0.5 cm3. The conditioning of the measuring capacity must be so, on the one hand it is achieved a signal strength if possible high - this as an advantage to a relatively large measuring capacity - and on the other hand you have to ensure a large homogeneity of the magnetic field permanent on the corresponding measuring capacity. The H nuclei of water molecules H2O especially serve for the NMR procedure. The so-called larmor frequency of H core amounts to 42 MHz / Tesla. The signal strength of the response signal S_ {R} is determined decisively by the homogeneity of the magnetic field in the air space. The objects relatively large metal in direct proximity to the magnet permanent, influence the homogeneity of the magnetic field in the air space, which leads to a widening of rays and thus almost or totally to an extinction of the NMR signal. The structure and mode of functioning of such detector D_ {1} shall be designated by the specialists such as the so-called NMR detector. Unique detectors D_ {1}, D_ {2} etc. are individually characterized by a particular number of turns N_ {1} N_ {2}, .. of the coil of gradient 11. The gradient coils 11 of the unique detectors D_ {1}, D_ {2} etc. are united in parallel with each other and connected in a gradient amplifier device (not drawn in figure 1a). The gradient amplifier device can thus  be part of the sending / receiving unit 5. The coils of Single broadcast / receive 14 are preferably connected from parallel to the sending / receiving unit 5; It is also possible a serial connection.

Below in figure 3 a pulse packet S_ {P} (also called pulse emitter), that is sent from the sending / receiving unit 5 to the detectors D_ {1}, D_ {2} etc. Immediately before, it is placed by the gradient amplifier device, a rectangular wave signal S_ {A} in gradient coils 11. The duration t_ {A} of this rectangular wave S_ {A} is, according to the acquisition period or also from the observation period called t_ {A} in about 2 seconds. Together with the number of individual turns of the coil of gradient 11, can be superimposed for each detector D1, D_ {2} etc. an individual complementary field to the magnet field permanent. Here this complementary field adapts to the location local detector D_ {K} in question. The adaptation can also be carried out in the evaluation unit with values of correction. By the number of individual turns N_ {1}, N_ {2} of the gradient coil of the detectors D_ {1}, D_ {2} ordered along a track 1, it is also sometimes a frequency band of the individual detector for the signal response S_ {R} in a pulse packet S_ {P} sent. The pulse width T_ {P} must be chosen so that all the hydrogen atoms in the different detectors D1, D2 etc. can be stimulated at the same time. That means that the Pulse bandwidth S_ {P} must be manifestly larger than the frequency deviation between the lowest and the Highest measured frequency. The values are shown below. Typical for impulse pack S_ {P}:

Frequency carrier:

21 MHz (In B 0 = 0.5 Tesla)

Duration of impulse:

5 \ mus

The response signal S_ {R} of a detector D in a pulse packet S_ {P} sent, it is represented in the Figure 3 also in the temporal field. The observation period typical (acquisition period), is in 1 second, the amplitude in the scope of mV. In the sending / receiving unit 5 or in a assigned evaluation unit, the signal response S_ {R} is represented by a Fourier transformation in space frequency The result of this representation of the signals of answer S_ {R} is indicated, in Figure 1b with a Simplified representation of the S_ {Rf} curve course. To who a split scale - however not represented as such - because of the number of turns N_ {1}, N_ {2} etc. individual are the different response signals P_ {1}, P_ {}} represented etc. It is assumed that in the environment of detector D3 there is a metallic object 6, which hinders both the magnetic field in the test  of water, which in a pulsation package emitted in space frequency does not produce or according to scale does not produce no representable P3 response signal. This way it download the information that the path along track 1 is busy and according to this no adjustment of  A signal for the passage of a train.

After the explanation made of the infrastructure, an implementation of the procedure is planned according to the invention, which after installation of the system already mentioned along a lane 1, the response signals P_ {1}, P_ {2} assigned by the detectors D_ {1}, D_ {2}, which they have been transformed into the frequency space and they are sent to pulse pack S_ {p}, are stored in the unit issuing / receiving 5 or in an evaluation unit. These response signals P1, P2, P3 etc. memorized it they can thus award them in total for all of them or individual tolerance bands. For the realization of procedure according to the invention, the previously referred to rectangular wave signal for acquisition as well as the package Pulse press S_ {P} are sent in a fixed reticule depending on the Time or according to the needs. The response signals S_ {R} so detailed they transform into the frequency space and it they compare with the response signals P1, P2, P3 etc. memorized An inequality or an inequality outside the Tolerance band mentioned above, leads to the production of a signal, which results in an occupation of the route 1 in question or of a section of the road. For an emission in a reticulum depending on the fixed time of for example 5 seconds can be provided in particular to memorize a selection of the response signals produced for example every 10 or 50 signal transcripts S_ {Rf}. This memorization allows in particular to recognize a slow change and produce either an alarm signal in what is refers to the system's ability to function and / or correct by a statistical procedure the response signals memorized From what you have to keep in mind that the values strangers find no entry in this so-called car calibration.

The embodiment described above of the process according to the invention was primarily adjusted to the detection of objects 6 extra-rail. He proposed procedure can be used however also by the same rail service and the chase of a train along of a section of the road.

The system and procedure according to the invention is not limited to the described embodiment previously, other evaluation procedures are possible, in particular through a two-dimensional Fourier transformer to be able to eliminate a delay time offset. That represents the most general case of the described embodiment example previously, in which the influence of the delay time is unattended The procedure explained above is not limited to the railway technique, but it can for example be used in an array array by detectors in a distance of for example 0.5 m also for object stop Metallic as mines.

List of the reference signs used and the abbreviations

one

Railroad track

2

Track axis

5

Broadcast / Receive Unit

6

Metallic object

10

Permanent magnet

eleven

gradient coil

12

 Water sample

14

Emission / Receive Coil

to

Distance of detectors D_ {1}, D_ {2} of track axis

D, D 1, D 2, D_ {K}, D_ {n}

Detectors

d_ {34}

Distance between detectors D_ {3} and D_ {4}

d_ {45}

Distance between detectors D_ {4} and D_ {5}

N 1, N 2

Number of turns of the gradient coil of the detectors D 1, D 2

NMR

Nuclear Magnetic Resonance

P1, P2,

Response signal of the respective detectors D_ {1}, D_ {2} in the frequency space

S_ {A}

Rectangular wave signal for the acquisition

S_ {P}

Pulsation package

MR}

Response signal of a detector D in the interval of weather

S_ {RF}

Signal path in the frequency local of all of the response signals S_ {R} transformed.

Claims (8)

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1. Object detection procedure (6) a along a railroad track (1) by the detectors (D_ {1}, D_ {2}, ..) positioned along the tracks, in which the signals of the detectors (D_ {1}, D_ {2}, ..) are memorized before in the absence of objects and the signals that are detected by the detectors (D_ {1}, D_ {2} ..) at a specific time it detect and compare with memorized signals, characterized because the detectors work according to the procedure Nuclear Magnetic Resonant (NMR) and according to the phases of process

TO

The response signals (S_ {R}) are detected in a pulse packet (S_ {P}) emitted to the detectors (D_ {{{}}}, D_ {2}, ..);

B

the response signals (S_ {R}) that are detected are transformed into a signal (S_ {RF}, P_ {1}, P_ {2}, ..) in space frequency;

C

the response signals (S_ {RF}, P_ {1}, P_ {2}, ..) transformed in the frequency space they are compared with the response signals previously memorized, which were memorized when you are sure of the absence of an object (6) according to the stages of the procedure A and B, in which a proven inequality is assessed as the presence of an object (6).

2. Method according to claim 1, characterized because the detectors (D_ {1}, D_ {2}, ..) are set in position along the railroad track (1) in a sequence (d_ {34}, d_ {45}, ..) that can be freely chosen. 3. Method according to claim 1 or 2, characterized because the detectors (D_ {1}, D_ {2}, ..) are set in position next to the railway tracks (1) 4. Procedure according to one of the claims 1 to 3, characterized because each detector (D_ {1}, D_ {2}, ..) has a gradient coil (11) surrounding a permanent magnet (10), a emission / reception coil (14) as well as a water sample (12). 5. Method according to claim 4 characterized because each detector (D1, D2, ..) is characterized by an individual number of turns (N 1, N 2), …) Of the gradient coil (11). 6. Procedure according to one of the claims 1 to 5 characterized because at the stage of procedure C the signals of response (S_ {RF}, P_ {1}, P_ {2}, ..) transformed into the Frequency space can be associated with the detectors (D_ {1}, D_ {2}, ..). 7. Procedure according to one of the claims 1 to 6 characterized because at the stage of procedure A they are issued some pulse packets (S_ {P}) in a time grid fixed to recognize a modification that occurs slowly. 8. Method according to claim 7 characterized because in the phase of procedure C a selection of response signals (S_ {RF}, P_ {1}, P_ {2}, ..) transformed into the frequency space over the packet of pulses (S_ {P}) emitted in a fixed grid based on the weather.