EP2870048B1 - Locating of rail vehicles - Google Patents

Description

The invention relates to a method having the features according to the preamble of patent claim 1.

Such a method is known from the international patent application WO 2011/027166 A1 and also from the patent US 5,330,136 known. In this prior art method, a waveguide is provided for locating a rail vehicle along a rail track, which is laid along the rail track. Electromagnetic pulses are fed one after the other into the waveguide. At least one backscatter pattern generated by vehicle-induced backscattering of the electromagnetic pulse is received and evaluated for each emitted pulse. By evaluating the backscatter patterns, the rail vehicle is located on the railway line.

The invention has for its object to provide a method for operating a locating device, which allows improved compared to previously known methods locating. This object is achieved by a method having the features according to claim 1. Advantageous embodiments of the method according to the invention are specified in subclaims.

Thereafter, the invention provides that the waveguide along the rail path has at least one extension section in which the length of the waveguide is longer by an excess length than this extension section associated portion of the rail track, the time backward pattern length of the received backscatter pattern is measured, determines the additional period of the backscatter pattern which results when passing the extension section compared to the backscatter pattern length before or after the extension section and the additional time period for generating an error signal or to calibrate the locating device is used.

A significant advantage of the method according to the invention is the fact that are used in this extension sections and measured by these induced additional periods measured and evaluated. If the additional periods of the extension sections are known in advance, the additional time periods measured during normal operation of the locating device can be used to generate an error signal if unusual deviations occur between the measured additional periods and the expected additional periods. If the additional periods of the extension sections are not yet known in advance, the additional time periods occurring can be measured and stored or used to calibrate the locating device in the course of a reference run (calibration run), so that subsequently in the further operation of the locating device an error signal formation can take place, as already has been described.

According to a preferred embodiment of the method, it is provided that an error signal indicating a malfunction of the locating device is generated when the additional time period exceeds or falls below a predefined desired additional time duration by a predetermined amount when an extension section passes.

The desired additional period of time is preferably determined by multiplying the excess length of the extension section by a predetermined proportionality factor.

According to a further preferred embodiment of the method, it is provided that a calibration of the locating device takes place, wherein the calibration of the locating device or the extension sections of the waveguide is located and their respective excess length is measured by the rail track is traveled by a reference rail vehicle whose actual length is known , the temporal Backscatter pattern length of the backscatter pattern is measured over time during the travel of the reference rail vehicle, in the event of a time extension of the backscatter pattern on passing one of the extension sections is closed and calculated on the basis of the additional period of the backscatter pattern in the respective section, the excess length of the extension section and / or the measured Additional time is stored as a desired additional period for the respective extension section.

According to a further preferred embodiment of the method, it is provided that during operation of the locating device, the length of the respective rail vehicle is measured, which travels the rail route by closing in the event of an occurring time extension of the backscatter pattern on passing one of the extension sections and on the basis of the additional period of the backscatter pattern in the respective section compared to the backscatter pattern length before or after the extension section, the length of the rail vehicle is calculated.

Preferably, an error signal is generated when the deviation between the length of the rail vehicle measured for one of the extension sections and the length of the rail vehicle measured for another of the extension sections reaches or exceeds a predetermined threshold value.

The invention further relates to a locating device for locating a rail vehicle along a railway track with a waveguide laid along the railway track, a pulse generating device for generating and feeding temporally successive electromagnetic pulses into the waveguide, a detection device for detecting backscatter patterns generated by backscattering and a Evaluation device for evaluating the backscatter patterns.

With regard to such a locating device, it is provided according to the invention that the waveguide has at least one extension section along the rail section, in which the length of the waveguide is longer by an excess length than the section of the rail section assigned to this extension section, and the evaluation device is designed such that it delays the time Measures the backscatter pattern length of the received backscatter pattern and determines the additional time duration of the backscatter pattern that results when passing the extension section by the rail vehicle compared to the backscatter pattern length before or after the extension section.

With regard to the advantages of the locating device according to the invention, reference is made to the above statements in connection with the method according to the invention, since the advantages of the method according to the invention essentially correspond to those of the locating device according to the invention.

It is considered to be particularly advantageous if the evaluation device is designed such that it generates an error signal indicating a malfunction of the locating device if the additional time duration exceeds or falls below a predefined desired additional time duration by a predetermined amount when passing through the extension section.

Alternatively or additionally, the evaluation device can be configured such that it locates the extension section or sections of the waveguide for calibration of the locating device, while the rail route is traveled by a reference rail vehicle whose actual length is known, wherein the time backward pattern length of the backscatter pattern over time is measured during the journey of the reference rail vehicle, in the event of an occurring time extension of the backscatter pattern on the passage of one of the extension sections is closed and on the basis of the additional period of the backscatter pattern in the respective section, the excess length of the extension section calculated and / or the measured additional period is stored as a desired additional period for the respective extension section.

Alternatively or additionally, the evaluation device can be designed such that during operation of the locating device it measures the length of the respective rail vehicle that travels along the rail route by closing the passage of one of the extension sections in the event of an occurring time extension of the backscatter pattern and by means of the additional period of time of the backscatter pattern in the respective section compared to the backscatter pattern length before or after the extension section calculates the length of the rail vehicle.

The waveguide preferably has a multiplicity of extension sections along the rail track. If a plurality of extension sections are present, then it is considered advantageous if the excess lengths of the extension sections differ in that at least two different overlengths are present.

Preferably, at least two of the extension portions, preferably all, are separated from each other by waveguide portions which have no excess length.

The arrangement of the extension sections preferably forms a location coding.

Particularly preferably, the length of the waveguide in the extension sections at least 10 times, preferably at least 100 times, greater than the length of the respective associated portion of the rail track, in order to ensure a simple and reliable location.

Figur 1

ein Ausführungsbeispiel für eine erfindungsgemäße Ortungseinrichtung zum Orten eines Schienenfahrzeugs entlang einer Schienenstrecke,

Figuren 2-4

beispielhaft Rückstreumuster, die ein Schienenfahrzeug auf der Schienenstrecke gemäß Figur 1 erzeugt,

Figur 5

ein Ausführungsbeispiel für einen Verlängerungsabschnitt, wie er bei der Ortungseinrichtung gemäß Figur 1 eingesetzt werden kann, wobei der Verlängerungsabschnitt einen aufgespulten Wellenleiter umfasst,

Figur 6

ein zweites Ausführungsbeispiel für einen Verlängerungsabschnitt, wie er bei der Ortungseinrichtung gemäß Figur 1 eingesetzt werden kann, wobei der Verlängerungsabschnitt durch eine Mäanderstruktur gebildet ist,

Figur 7

ein drittes Ausführungsbeispiel für einen Verlängerungsabschnitt, wie er bei der Ortungseinrichtung gemäß Figur 1 verwendet werden kann, wobei der Verlängerungsabschnitt einen Mäanderabschnitt sowie einen aufgespulten Wellenleiterabschnitt umfasst, und

Figur 8

ein weiteres Ausführungsbeispiel für eine erfindungsgemäße Ortungseinrichtung, bei der Verlängerungsabschnitte eine Ortskodierung bilden.

The invention will be explained in more detail with reference to embodiments; thereby show by way of example

FIG. 1

An embodiment of a locating device according to the invention for locating a rail vehicle along a rail track,

Figures 2-4

Exemplary backscatter pattern, which generates a rail vehicle on the railway line according to Figure 1,

FIG. 5

an embodiment of an extension portion, as in the locating device according to FIG. 1 can be used, wherein the extension section comprises a coiled waveguide,

FIG. 6

a second embodiment of an extension portion, as in the locating device according to FIG. 1 can be used, wherein the extension section is formed by a meander structure,

FIG. 7

a third embodiment of an extension portion, as in the locating device according to FIG. 1 can be used, wherein the extension portion comprises a meandering section and a coiled waveguide section, and

FIG. 8

a further embodiment of a locating device according to the invention, wherein the extension sections form a spatial coding.

For the sake of clarity, the same reference numbers are always used in the figures for identical or comparable components.

The FIG. 1 shows a locating device 10, a pulse generating device 20, a detection device 30, an optical coupling device 40, a waveguide 50 z. B. in the form of an optical waveguide and an evaluation device 60 includes.

The pulse generating device 20 preferably has a laser, which is not further shown, and which makes it possible to generate pulses, for example at a fixed pulse rate, of short electromagnetic, in particular optical, pulses and to feed them into the waveguide 50 via the coupling device 40. The pulse generating device 20 is preferably activated by the evaluation device 60, so that the evaluation device 60 is at least approximately aware of the times of pulse generation.

The detection device 30 has, for example, a photodetector which makes it possible to detect electromagnetic radiation. The detection device 30 transmits its measurement signals to the evaluation device 60, which evaluates them.

In the FIG. 1 It can be seen that the waveguide 50 is arranged along a rail track 100. On the railway line 100 a rail vehicle 110 travels along the direction of the arrow P from left to right. In the representation according to the FIG. 1 For example, the movement of the rail vehicle 110 along the arrow direction P is symbolized by two further positions (compare rail vehicle positions 110 'and 110 ").

The FIG. 1 shows that the waveguide 50 is provided with extension sections 51, 52 and 53 in which the length of the waveguide 50 is greater than the length of the associated sections of the rail track 100. Outside the extension sections 51 to 53, the waveguide 50 is approximately the same length as the Rail section 100. The difference in length or the excess length in the extension sections 51 to 53 is based, for example, on the fact that the waveguide 50 is curved several times in these sections.

Embodiments of the embodiment of the extension portions 51 to 53 are in the FIGS. 5 to 7 shown; These figures will be discussed below.

The locating device 10 according to FIG. 1 can be operated to locate the rail vehicle 110, for example, as follows:

The evaluation device 60 controls the pulse generating device 20 in such a way that it feeds electromagnetic pulses Pin in succession via the coupling device 40 into the waveguide 50. The generated electromagnetic pulses travel along the arrow direction P in FIG FIG. 1 from left to right and are preferably absorbed at the waveguide end 50a by an absorber 200.

By traveling on the rail track 100 rail vehicle 110, the waveguide 50 is locally shaken or vibrated; this is in the FIG. 1 indicated by arrows with the reference Ms. Due to these vibrations or due to the vibrations of the waveguide 50, a backscattering of the electromagnetic radiation will occur locally in the area in which the rail vehicle 110 is currently located. The backscattered radiation has a backscatter pattern that is characteristic of the vibration caused by the rail vehicle 110 and coupled into the waveguide 50.

The backscattered radiation runs counter to the direction of travel P of the rail vehicle in the direction of the coupling device 40 and in the direction of the detection device 30 and is detected there by the detection device 30. The detection device 30 is designed such that it measures the intensity of the backscattered radiation and forwards a corresponding measurement signal to the evaluation device 60. The intensity the backscattered radiation is in the FIG. 1 marked with the reference Ir (t).

The evaluation device 60 will evaluate the backscattered radiation Ir (t) and the backscatter patterns contained therein. If the time length of the received backscatter patterns extends over time, it will infer the passage of one of the extension sections 51 to 53 and produce a location signal S o. This should be closer to the FIGS. 2 to 4 be explained.

In the FIG. 2 For example, a backscatter pattern Rm1 is shown which arrives in the evaluation device 60 if an electromagnetic pulse from the pulse device 20 has been irradiated into the waveguide 50 at the time t = 0. The length of the received backscatter pattern Rm1 is in the FIG. 2 marked with the reference numeral dt1.

The backscatter pattern Rm1 refers to the position of the rail vehicle according to FIG FIG. 1 as denoted by solid lines and the reference numeral 110.

Now moves the rail vehicle 110 along the direction of arrow P according to FIG. 1 further and reaches the position indicated by the reference numeral 110 ', it will put the extension portion 51 of the waveguide 50 in mechanical vibration. In the region of the extension section 51, however, the length of the waveguide 50 is much greater than the corresponding length of the associated section of the rail track 100, so that a temporal extension of the backscatter pattern occurs. This is in the FIG. 3 shown.

In the FIG. 3 It can be seen that the time length dt2 of the backscatter pattern Rm2 is much larger than the time length dt1 of the backscatter pattern Rm1. The enlargement or temporal extension of the backscatter pattern Rm2 is due to the fact that the extension section 51 is much longer than the assigned section of the rail track 100. The time length dt2 of the backscatter pattern Rm2 is composed of the time length dt1 of the backscatter pattern Rm1 and an additional period of time dtz according to: $$\mathrm{dt}2=\mathrm{dt}1+\mathrm{dtz}\mathrm{,}$$

If the time lengths dt1 of the backscatter pattern Rm1 and dt2 of the backscatter pattern Rm2 are measured, the additional time duration dtz can be calculated, in accordance with FIG $$\mathrm{dtz}=\mathrm{dt}2-\mathrm{dt}1$$

The calculated additional period dtz can now be used to check the operation of the locating device, to calibrate the locating device or to measure the length of rail vehicles, as will be explained below by way of example:

1. Check the functioning of the locating device:

In order to check the functioning of the locating device, the calculated additional time duration dtz can be compared with a desired additional time duration dtsoll specified for the extension section 51. If the deviation between the calculated additional time duration dtz and the desired additional time duration dtsoll is too great or greater than a predefined threshold value Dmax, the evaluation device 60 generates an error signal F indicating a malfunction of the positioning device: $$\left|\mathrm{dtz}-\mathrm{dtSoll}\right|\ge \mathrm{Dmax}\Rightarrow \mathrm{error\; signal}$$

The desired additional period dtsoll for the extension section 51 can be determined, for example, by multiplying the excess length dL of the extension section 51 of the waveguide 50 by a predetermined proportionality factor k, according to: $$\mathrm{dtSoll}=\mathrm{dL}*\mathrm{k}$$

The excess length dL of the extension portion 51 may be measured (see below in the section "Calibrating the Locator") or known from laying the waveguide 50.

2. Calibrate the locating device

wobei k einen Proportionalitätsfaktor angibt, für den näherungsweise gilt: $$\mathrm{k}=1/2*1/\mathrm{V}$$

wobei V die Geschwindigkeit der Pulse im Wellenleiter 50 angibt. Der Faktor 1/2 berücksichtigt, dass die Strahlung den Verlängerungsabschnitt 51 zweimal durchlaufen muss, nämlich einmal in Hinrichtung und einmal in Rückrichtung. Für die Geschwindigkeit V gilt beispielsweise: $$\mathrm{V}=\mathrm{c}0/\mathrm{n}$$

wobei c0 die Lichtgeschwindigkeit und n die Brechzahl im Wellenleiter 50 angibt.For calibrating the locating device, in particular for determining the desired additional duration dtsoll or the excess length dL of the extension sections, the extension sections 51-53 of the waveguide 50 can be located and their respective excess length measured by the rail line 100 from a reference rail vehicle (eg the rail vehicle 110 according to FIG. 1 ), whose length is known in advance. During the journey of the rail vehicle 110, the temporal backscatter pattern length of the backscatter pattern is measured over time. In case of a time extension of the backscatter pattern (see backscatter pattern Rm2 in FIG. 3 ) is directed to the passage of one of the extension portions (eg, extension portion 51 in FIG FIG. 1 ) closed. Based on the additional period dtz of the backscatter pattern Rm2 in the respective section, the excess length dL of the extension section can be calculated and / or the measured additional period dtz can be stored as the desired additional period dtsoll for the respective extension section 51. The calculation of the excess length dL can be done, for example, as follows: $$\mathrm{dL}=\left(\mathrm{dt}2-\mathrm{dt}1\right)/\mathrm{k}$$

where k is a proportionality factor that approximates: $$\mathrm{k}=1/2*1/\mathrm{V}$$

where V indicates the velocity of the pulses in the waveguide 50. The factor 1/2 takes into account that the radiation must pass through the extension section 51 twice, namely once in execution and once in return. For the velocity V, for example: $$\mathrm{V}=\mathrm{<figure-callout\; id="0"\; label="c"\; filenames="imgf0002.png"\; state="\{\{state\}\}">c</figure-callout>}0/\mathrm{n}$$

where c0 indicates the speed of light and n the refractive index in waveguide 50.

3. Measuring the length of rail vehicles:

wobei k den o. g. Proportionalitätsfaktor angibt, für den näherungsweise gilt: $$\mathrm{k}=1/2*1/\mathrm{V}\mathrm{.}$$

In addition to a location of rail vehicles, it is also possible to measure the length of the respective rail vehicle 100. In the case of a time extension of the backscatter pattern (see backscatter pattern Rm2 in FIG. 3 ) is moved to passing the extension portion 51 in FIG FIG. 1 closed, as already explained above. Based on the additional period dtz of the backscatter pattern Rm2 in the extension section 51 compared to the backscatter pattern length before or after the extension section 51, the length Lsf of the rail vehicle 100 can be calculated according to: $$\mathrm{spf}=\left(\mathrm{dt}2-\mathrm{dtz}\right)/\mathrm{k}$$

where k indicates the above-mentioned proportionality factor for which approximately $$\mathrm{k}=1/2*1/\mathrm{V}\mathrm{,}$$

If the rail vehicle length Lsf is determined for each of the extension sections 51-53, then a comparison with the values in the previously traveled extension sections is preferably carried out. If it is determined that the rail vehicle length Lsf has changed while driving, an error signal F is generated by the evaluation device 60, which indicates that either the locating device 10 is defective or the rail vehicle 110 has changed its length. The latter case may occur, for example, when a train separation has occurred, e.g. B. the rail vehicle 110 has lost a car by uncoupling.

The rail vehicle 110 leaves the area of the extension section 51 again and enters the area between the two extension sections 51 and 52 according to FIG FIG. 1 (See the position of the rail vehicle indicated by reference numeral 110 "in FIG FIG. 1 ), the extension of the backscatter pattern will be repeated and the length dt3 of the backscatter pattern Rm3 (cf. FIG. 4 ) is again the original time length dt1 of the backscatter pattern Rm1 according to FIG. 2 correspond.

In summary, the evaluation device 60 is thus able to use the time lengths dt1, dt2 and dt3 of the backscatter patterns Rm1, Rm2 and Rm3 to determine the location of the rail vehicle 110 on the rail track 100, because the location of the extension sections 51 to 53 along the rail track 100 is known to perform a calibration of the locating device 10 based on a reference travel of a reference rail vehicle to determine the length of the extension sections 51-53 or their Sollzusatzzeitdauern, and / or to determine the length of the rail vehicles.

By counting the output signals generated by the evaluation device 60 on the output side So also the travel of the rail vehicle can be tracked.

In addition to a location of the rail vehicle 110 on the basis of the extension sections 51 to 53, the detection device 30 can also make a location based on the time periods that result between the feeding of the electromagnetic pulses Pin in the waveguide 50 and the detection of the respective associated backscatter pattern Rm1, Rm2 and Rm3 ,

In the Figures 2-4 It can be seen that the time spans between the respective electromagnetic pickup pulse Pin and the associated backscatter pattern Rm1, Rm2 and Rm3 during the travel of the rail vehicle 110 on the rail track 100 increase; This is due to the fact that the propagation time of the electromagnetic pulses and the duration of the electromagnetic backscatter patterns in the waveguide 50 increase with increasing distance of the rail vehicle 110 from the pulse generating device 20 and the detection device 30.

wobei V die Geschwindigkeit der Pulse im Wellenleiter 50 angibt. Die Zeitspanne T2 kann der Messung gemäß Figur 3 entnommen werden. Der Faktor 1/2 berücksichtigt, dass die Strahlung den jeweiligen Wellenleiterabschnitt zweimal durchlaufen muss, nämlich einmal in Hinrichtung und einmal in Rückrichtung. Für die Geschwindigkeit V gilt beispielsweise: $$\mathrm{V}=\mathrm{c}0/\mathrm{n}$$

wobei c0 die Lichtgeschwindigkeit und n die Brechzahl im Wellenleiter 50 angibt.The evaluation device 60 is thus able to use the time periods T1, T2 and T3 to determine the distance and thus the location of the rail vehicle 110 and to generate a corresponding distance signal Se. The distance Ls of the rail vehicle 110 'in FIG. 1 can for example be calculated according to: $$\mathrm{ls}=1/2*\mathrm{T}2/\mathrm{V}$$

where V indicates the velocity of the pulses in the waveguide 50. The time period T2 may be the measurement according to FIG. 3 be removed. The factor 1/2 takes into account that the radiation must pass through the respective waveguide section twice, namely once in the direction of execution and once in the return direction. For the velocity V, for example: $$\mathrm{V}=\mathrm{<figure-callout\; id="0"\; label="c"\; filenames="imgf0002.png"\; state="\{\{state\}\}">c</figure-callout>}0/\mathrm{n}$$

where c0 indicates the speed of light and n the refractive index in waveguide 50.

The detection device 30 is thus able to additionally determine the location of the rail vehicle 110 on the basis of the time periods T1, T2 and T3, which pass between the transmission of the pulses Pin and the reception of the respective backscatter pattern Rm1, Rm2 and Rm3.

It is considered particularly advantageous if the evaluation device 60 in the case of locating the rail vehicle 110 in the region of one of the extension sections 51 to 53 and the generation of a corresponding location signal So additionally performs a plausibility check.

Such a plausibility check can be carried out, for example, such that the evaluation device 60 recognizes one of the extension sections 51 to 53 and the generation of a location signal So the time interval between pulse generation and arrival of the backscatter pattern (cf. FIG. 3 ) and determines the distance Ls of the rail vehicle 110. Subsequently, the evaluation device 60 can check whether the distance signal Se coincides with the formed location signal So.

For example, the evaluation device 60 will generate an error signal F if the difference between the position Ls indicated by the distance signal Se and the known position of the recognized extension section 51 exceeds a predetermined threshold value. The same applies to plausibility checks in the other extension sections.

The FIG. 5 shows an embodiment of an extension portion 300, as it as extension portion 51 to 53 in the locating device 10 according to FIG. 1 can be used. It can be seen that the waveguide 50 is wound several times in the region of the extension section 300 and forms a waveguide coil 310. By winding or winding up the waveguide 50, a substantial extension of the waveguide 50 with respect to the associated section of the rail track 100 is achieved, so that the temporal extension of the backscatter patterns (see backscatter pattern Rm2 in FIG FIG. 3 ) is significant.

The FIG. 6 shows another embodiment of an extension portion 300, as it as extension portion 51 to 53 in the locating device 10 according to FIG. 1 can be used. It can be seen that the waveguide 50 has a meandering structure 320, through which a considerable extension of the waveguide 50 with respect to the associated portion of the rail line 100 is caused. This leads to the explained time extension of the backscatter pattern, by which a location of the rail vehicle 110 on the rail track 100 according to FIG. 1 is possible.

In the FIG. 7 For example, one embodiment of an extension portion 300 having both a waveguide coil 310 and a meandering structure 320 is shown. With regard to the configuration of the waveguide coil 310 and the meander structure 320, reference is made to the above statements in connection with FIGS FIGS. 5 and 6 directed.

The FIG. 8 shows a further embodiment of a locating device 10 according to the invention, in which the waveguide 50 has a plurality of extension sections 51 to 55, which are arranged so that they form a spatial coding. By this location coding, it is possible to detect the location of the rail vehicle 110 on the railroad track 100 without having to observe and count the occurrence of the extension sections.

For reasons of clarity, the location coding is indicated by a coded arrangement of the extension sections 51 to 55 only by means of a few extension sections; It goes without saying that the location coding can be optimized in terms of its accuracy and readability, if a much larger number of extension sections is used.

The spatial coding by a local coding of the arrangement of the extension sections can be effected, for example, by forming binary coding patterns by the extension sections.

Although the invention has been illustrated and described in detail by preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

10

locating device

20

Pulse generating means

30

detection device

40

coupling device

50

waveguides

50a

Waveguide end

51-55

extension sections

60

evaluation

100

railway line

110

track vehicle

110 '

Rail vehicle position

110 '

Rail vehicle position

200

absorber

300

extension section

310

Fiber coil

320

meander

dt1

Length of the backscatter pattern

dt2

Length of the backscatter pattern

dt3

Length of the backscatter pattern

F

error signal

Ir (t)

backscattered radiation

ls

Distance / City

ms

Arrow / vibration

P

Arrow / direction

Pin code

electromagnetic pulses

Rm1

Backscatter

R m2

Backscatter

rm3

Backscatter

se

distance signal

So

location signal

T1

Period of time

T2

Period of time

T3

Period of time

Claims (14)

1. Method for operating a locating device (10), which comprises a waveguide (50) laid along a track segment (100) in order to locate a rail vehicle (110) on the track segment (100), wherein in the method, electromagnetic pulses (Pin) are fed into the waveguide (50) in succession and backscattering patterns (Rm1-Rm3) produced by backscattering of the electromagnetic pulse (Pin) are received and evaluated for each emitted pulse,
   characterised in that

   - the waveguide (50) has at least one extension section (51-55) along the track segment (100), in which extension section the length of the waveguide (50) is longer than the section of the track segment (100) associated with said extension section (51-55) by an excess length,

   - the temporal backscattering pattern length of the received backscattering pattern (Rm1-Rm3) is measured,

   - the additional duration of the backscattering pattern (Rm1-Rm3) resulting from the passage over the extension section (51-55) in comparison with the backscattering pattern length before or after the extension section (51-55) is determined and

   - the additional duration is used to generate an error signal (F) or to calibrate the locating device (10).
2. Method according to claim 1,
   characterised in that
   an error signal (F) indicating a malfunction of the locating device (10) is generated when during the passage over the extension section (51-55) the additional duration exceeds or falls below a predetermined target additional duration by a predetermined amount.
3. Method according to claim 2,
   characterised in that
   the target additional duration is determined by multiplying the excess length of the extension section (51-55) by a predetermined proportionality factor.
4. Method according to one of the preceding claims, characterised in that
   for calibrating the locating device (10) the extension section or extension sections (51-55) of the waveguide (50) are located and measured, by

   - running a reference rail vehicle, whose actual length is known, over the track segment (100),

   - measuring the temporal backscattering pattern length of the backscattering pattern (Rm1-Rm3) over time during the journey of the reference rail vehicle,

   - in the case of a temporal extension of the backscattering pattern (Rm1-Rm3) occurring, inferring the passage over one of the extension sections (51-55) and

   - based on the additional duration of the backscattering pattern (Rm1-Rm3) in the relevant section, calculating the excess length of the extension section (51-55) and/or saving the measured additional duration as the target additional duration for the respective extension section (51-55).
5. Method according to one of the preceding claims,
   characterised in that
   during the operation of the locating device (10) the length of the respective rail vehicle (110) which is traversing the track segment (100) is measured, by

   - in the case of a temporal extension of the backscattering pattern (Rm1-Rm3) occurring, inferring the passage over one of the extension sections (51-55) and

   - based on the additional duration of the backscattering pattern (Rm1-Rm3) in the relevant section, in comparison with the backscattering pattern length before or after the extension section (51-55), calculating the length of the rail vehicle (110).
6. Method according to claim 5,
   characterised in that
   an error signal (F) is generated if the deviation between the length of the rail vehicle (110) measured for one of the extension sections (51-55) and the length of the rail vehicle (110) measured for another of the extension sections (51-55) reaches or exceeds a predetermined threshold value.
7. Locating device (10) for locating a rail vehicle (110) along a track segment (100) having

   - a waveguide (50) laid along the track segment (100),

   - a pulse generator (20) for generating and feeding consecutive electromagnetic pulses (Pin) into the waveguide (50),

   - a detection device (30) for detecting backscattering patterns (Rm1-Rm3) generated by backscattering and

   - an evaluation device (60) for evaluating the backscattering pattern (Rm1-Rm3),

   characterised in that

   - the waveguide (50) has at least one extension section (51-55) along the track segment (100), in which extension section the length of the waveguide (50) is longer than the section of the track segment (100) associated with said extension section (51-55) by an excess length, and

   - the evaluation device (60) is designed such that it measures the temporal backscattering pattern length of the received backscattering pattern (Rm1-Rm3) and determines the additional duration of the backscattering pattern (Rm1-Rm3) resulting from the passage of the rail vehicle (110) over the extension section (51-55) in comparison with the backscattering pattern length before or after the extension section (51-55).
8. Locating device (10) according to claim 7,
   characterised in that
   the evaluation device (60) is designed such that it generates an error signal (F) indicating a malfunction of the locating device (10) when during the passage over the extension section (51-55) the additional duration exceeds or falls below a predetermined target additional duration by a predetermined amount.
9. Locating device (10) according to claim 7 or 8,
   characterised in that
   the evaluation device (60) is designed such that to calibrate the locating device (10) it locates and measures the extension section or extension sections (51-55) of the waveguide (50) while the track segment (100) is traversed by a reference rail vehicle whose actual length is known,

   - wherein the temporal backscattering pattern length of the backscattering pattern (Rm1-Rm3) is measured over time during the journey of the reference rail vehicle,

   - in the case of a temporal extension of the backscattering pattern (Rm1-Rm3) occurring, the passage over one of the extension sections (51-55) is inferred and

   - based on the additional duration of the backscattering pattern (Rm1-Rm3) in the relevant section, the excess length of the extension section (51-55) is calculated and/or the measured additional duration is saved as a target additional duration for the respective extension section (51-55).
10. Locating device (10) according to one of the preceding claims 7-9,
    characterised in that
    the evaluation device (60) is designed such that during the operation of the locating device (10) it measures the length of the respective rail vehicle (110) which is traversing the track segment (100), by

    - in the case of a temporal extension of the backscattering pattern (Rm1-Rm3) occurring, it infers the passage over one of the extension sections (51-55) and

    - based on the additional duration of the backscattering pattern (Rm1-Rm3) in the relevant section in comparison with the backscattering pattern length before and after the extension section (51-55) it calculates the length of the rail vehicle (110).
11. Locating device (10) according to one of claims 7-10,
    characterised in that
    the waveguide (50) along the track segment (100) has a plurality of extension sections (51-55).
12. Locating device (10) according to claim 11,
    characterised in that
    the excess lengths of the extension sections (51-55) differ to the extent that at least two different excess lengths are present.
13. Locating device (10) according to one of claims 7-12,
    characterised in that
    at least two of the extension sections (51-55), preferably all, are separated from one another by waveguide sections that have no excess length.
14. Locating device (10) according to one of claims 7-13,
    characterised in that
    the arrangement of the extension sections (51-55) forms a spatial encoding.

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