EP4331940A1 - Method and evaluation unit for operating a multi-unit vehicle, in particular a railway train - Google Patents

Abstract

The invention relates, among other things, to a method for operating a multi-unit vehicle, in particular a railway train. According to the invention, while the vehicle is traveling, a property dependent on the respective location of the route (30) being traveled is measured over time using a front sensor (21) arranged in the area of a front end of the vehicle, forming a first property curve (EV1). , while the vehicle is traveling, the property dependent on the respective location of the route (30) being traveled is measured over time with a rear sensor (22) arranged in the area of a rear end of the vehicle, forming a second property curve (EV2), the first and second property curve (EV1, EV2) is subjected to a correlation test to form a time distance value (dT), which is the time distance between a second point in time (t2) at which the rear sensor (22) has already passed one of the front sensor (21). location has passed or has passed, and indicates a first time (t1) at which the front sensor (21) has already passed the said location, and based on the time distance value (dT), the length of the vehicle is formed, forming a length value ( LZ) is determined.

Description

The invention relates to a multi-part vehicle, in particular a railway train; a method for its operation, an evaluation device for a vehicle and a software program product for a vehicle.

In the field of railway technology, the European train control system European Train Control System (ETCS) is known, in its so-called Level 3, track clearance notification and train completeness control should no longer be carried out by signal boxes, but by a so-called Radio Block Center with the participation of the train. Track-side track clearance notification, which is still necessary in Level 2, for example through axle counters or track circuits, is no longer necessary.

In order to enable railway trains to travel in Level 3, they must have their own train integrity control system (see ETCS specification, subset 026, 3.6.0, section 2.6.7.2.3). The safety requirements for this correspond to safety level SIL4.

In order to implement a reliable, robust train-side completeness report for trains with variable train composition, in particular freight trains, various methods have already been discussed, for example methods based on monitoring the pressure and mass flow in the main air line, a transit time measurement via ultrasound in the main pressure line, and additional cabling along the train or a distance measurement to an End-of-Train (EoT) device via radio, such as in the European patent specification EP 3 337 708 B1 is described.

The invention is based on the object of specifying an operating method that delivers at least one measured value based on which A reliable completeness check can be carried out on a basis.

This object is achieved according to the invention by a method with the features according to claim 1. Advantageous embodiments of the method according to the invention are specified in the subclaims.

According to the invention, it is then provided that, while the vehicle is traveling, a property dependent on the respective location of the route traveled is measured over time to form a first characteristic curve with a front sensor arranged in the area of a front end of the vehicle, while the vehicle is traveling with a rear sensor arranged in the area of a rear end of the vehicle, the property dependent on the respective location of the route traveled is measured over time to form a second property curve, the first and second property curves are subjected to a correlation test to form a time distance value which is the time distance between a second time at which the rear sensor passes or has already passed a location previously passed by the front sensor, and a first time at which the front sensor has already passed the said location, and based on the time distance value, the length of the vehicle is determined by forming a length value.

A significant advantage of the method according to the invention is that it enables the length of the vehicle to be determined in a particularly simple manner, even when cornering. The length measurement value determined in the manner according to the invention can advantageously be used, for example, to check the completeness of the vehicle.

Preferably, a train completeness signal is generated when the length value corresponds to a predetermined target value or at least does not deviate from this beyond a specified level. Alternatively or additionally, it can be provided that an alarm signal is generated if the length value deviates from the predetermined target value beyond the predetermined amount.

It is advantageous if, as part of the correlation test, a cross-correlation function is determined with the first and second characteristic curves and the time distance value is determined using the cross-correlation function.

The formation of the length value preferably includes the multiplication of the time distance value by a speed value indicating the speed of the vehicle.

If the measured values are recorded at constant time intervals to measure the property curves, accelerations at which the speed is increased can cause signal compression in the time course of the property curves; Accelerations at which the speed is reduced can cause signal spreads in the time course of the property curves. For this reason, it is considered advantageous if the correlation test includes a correction of acceleration-related signal influences on the first and second property curves by spreading acceleration-related signal compressions over time, for example on the computer side, and acceleration-related signal spreads, for example, compressing them on the computer side.

It is advantageous if the correlation test for the purpose of correcting signal spreads and/or signal compressions includes a conversion of the first measured property curve into a first speed-normalized property curve and a conversion of the second measured property curve into a second speed-normalized property curve and the correlation test also includes, to determine a cross-correlation function with the first and second speed-normalized property curves and to determine the time distance value using this cross-correlation function.

The conversion of the first measured property curve into the first speed-normalized property curve and the conversion of the second measured property curve into the second speed-normalized property curve is preferably carried out on the basis of a predetermined normalization speed value; the formation of the length value preferably includes the multiplication of the time distance value by the normalization speed value.

Alternatively, it can advantageously be provided that the measurement of the property measurement values for the first and second property curves takes place at fixed local intervals or fixed local distances, i.e. equidistant in terms of location. In this case, the recording of the measured values is not equidistant in time, but rather variable depending on the speed. The acquisition of the property measurement values for the first and second property curves can, for example, be triggered on the travel pulse generator side at fixed distances or fixed local distances. The advantage of the last-mentioned embodiment is that the aforementioned signal compressions and signal spreads are avoided during speed changes and a subsequent correction in this regard can be dispensed with.

The front sensor is preferably attached to the first car of the multi-section vehicle or railway train and the rear sensor is preferably attached to the last car of the multi-section vehicle or railway train in order to be able to determine the total length particularly accurately.

The speed value can be measured or calculated from measured values, for example taking measured values into account distance increments traveled and related time intervals, Doppler radar measurement values and/or measured acceleration values.

It is advantageous, for example, if the speed value is determined by means of two sensors that are offset in the longitudinal direction of the vehicle but are closely adjacent and are preferably attached to different ends of the same car at a known distance from one another and each have a property that depends on the respective location of the route traveled over time measure while forming property curves. By means of a correlation test, a time distance value can then be determined - as explained above in connection with the length determination - which is the time distance between a second point in time at which the rear of the latter two sensors passes a location previously passed by the front of the latter two sensors or has happened, and indicates a first time at which the front of the latter two sensors has already passed the named location. The speed value can then be calculated on the basis of this time distance value and the known distance between the sensors.

It is therefore possible that there are two sensors for measuring the speed value and two sensors for measuring length, i.e. four sensors. However, it is advantageous if one sensor is saved and one of the sensors is used for both speed measurement and length measurement.

The front of the two sensors used for speed measurement can be the sensor that is used as the front sensor for length measurement; The rear sensor used for speed measurement would then be a sensor in addition to the rear sensor used for length measurement. Accordingly, the rear of the two sensors used for speed measurement can alternatively be used be the rear sensor used for length measurement; The front sensor used for speed measurement would then be an additional sensor, in addition to the front sensor used for length measurement.

The property that is dependent on the location of the route being traveled and which is measured by the sensors can be a property of a radar reception signal that has penetrated a floor of the route being traveled over. The last-mentioned variant can be based, for example, on sensors, as described in the publication " "Localizing Ground Penetrating RADAR: A Step Toward Robust Autonomous Ground Vehicle Localization" (Matthew Cornick, Jeffrey Koechling, Byron Stanley, and Beijia Zhang MIT Lincoln Laboratory, 244 Wood St. Lexington, Massachusetts 02420, Received May 21, 2014 ) are described.

Alternatively or additionally, other properties can be measured by the sensors for generating the property curves, such as a property of a received Doppler signal from a constant wave radar, which sends a radar signal at least in the direction of the track floor, a property of a magnetic field, which is preferably generated on the track side and detected on the vehicle side the permeability of a rail on the route traveled and/or the roughness of the rail.

The determination of the length value indicating the length of the vehicle does not have to be based solely on a single property; For example, property progressions can be determined on the basis of two or more properties and length values can be determined for each of the properties. If two or more length values are available, they can be compared and subjected to a plausibility check. For example, a warning signal can be generated if the length values deviate from one another by a predetermined amount.

The invention also relates to a multi-part vehicle, in particular a railway train. According to the invention, it is provided with regard to the vehicle that a front sensor is arranged in the area of a front end of the vehicle, which measures a property dependent on the respective location of a route traveled over time to form a first property curve, and a rear sensor in the area of a rear end of the vehicle Sensor is arranged, which measures the property dependent on the respective location of the route traveled over time to form a second property curve, and an evaluation device connected to the first and second sensors is present, which uses the first and second property curves of a correlation test to form a temporal distance value, which indicates the time interval between a second time at which the rear sensor passes or has already passed a location previously passed by the front sensor, and a first time at which the front sensor has already passed the named location, and based on the time distance value, the length of the vehicle is determined to form a length value. With regard to the advantages of the vehicle according to the invention and its advantageous embodiments, reference is made to the above statements in connection with the method according to the invention and its advantageous embodiments.

The invention also relates to an evaluation device for a vehicle, in particular a vehicle as described above. According to the invention, with regard to the evaluation device, it is provided that the evaluation device is designed to subject a first property curve, which was detected by a front sensor, and a second property curve, which was detected by a rear sensor, to a correlation test to form a time distance value the time interval between a second point in time at which the rear sensor passes or has passed a location previously passed by the front sensor, and a first point in time at which the front sensor Sensor has already passed the named location and determines the length of the vehicle based on the time distance value, forming a length value. With regard to the advantages of the evaluation device according to the invention and its advantageous embodiments, reference is made to the above statements in connection with the method according to the invention and its advantageous embodiments.

The evaluation device is preferably integrated into a vehicle computer of a vehicle, in particular a rail vehicle.

The evaluation device preferably comprises a correlation module for checking the correlation and forming the time distance value and a multiplication module for forming the length value by multiplying the time distance value with a speed value indicating the speed of the vehicle.

The invention also relates to a software program product. According to the invention, it is provided with regard to the software program product that, when executed by a computing device, this causes the latter to form an evaluation device as described, i.e. a first characteristic curve that was detected by a front sensor and a second characteristic curve that was detected by a rear sensor , to subject a correlation test to form a time distance value, which is the time distance between a second time at which the rear sensor passes or has passed a location previously passed by the front sensor, and a first time at which the front sensor passes the said location Place has already passed, and based on the time distance value to determine the length of the vehicle to form a length value.

The software program product is preferably in the software of a vehicle computer of a vehicle, in particular a rail vehicle, integrated or at least installed on such a vehicle computer. Alternatively, it can also be installed on a trackside computer to which the sensor data is transmitted, for example by radio. As an alternative to the above-mentioned embodiment, the software program product can also have program instructions for carrying out the method according to the invention according to one of the above-mentioned embodiments.

Figur 1

ein Ausführungsbeispiel für ein erfindungsgemäßes mehrgliedriges Fahrzeug,

Figur 2

Eigenschaftsverläufe, die von einem vorderen und einem hinteren Sensor des Fahrzeugs gemäß Figur 1 gemessen werden,

Figur 3

ein Ausführungsbeispiel für eine Auswerteinrichtung des Fahrzeugs gemäß Figur 1,

Figur 4

eine distanzgetriggerte Messwertaufnahme zum Erzeugen von beschleunigungsunabhängigen Eigenschaftsverläufen,

Figur 5

eine vorteilhafte technische Realisierung der Auswerteinrichtung gemäß Figur 3,

Figur 6

ein weiteres Ausführungsbeispiel für ein erfindungsgemäßes mehrgliedriges Fahrzeug,

Figur 7

ein Ausführungsbeispiel für einen Sensor, der bei den Fahrzeugen gemäß Figur 1 und 6 eingesetzt werden kann, und

Fig. 8-10

Messwerte des Sensors gemäß Figur 7 und eine daraus abgeleitete Kreuzkorrelationsfunktion.

The invention is explained in more detail below using exemplary embodiments, with examples showing:

Figure 1

an exemplary embodiment of a multi-unit vehicle according to the invention,

Figure 2

Property curves from a front and a rear sensor of the vehicle according to Figure 1 be measured,

Figure 3

an embodiment of an evaluation device of the vehicle according to Figure 1 ,

Figure 4

a distance-triggered measurement recording to generate acceleration-independent property curves,

Figure 5

an advantageous technical implementation of the evaluation device Figure 3 ,

Figure 6

a further exemplary embodiment of a multi-part vehicle according to the invention,

Figure 7

an embodiment of a sensor in the vehicles according to Figure 1 and 6 can be used, and

Fig. 8-10

Measured values of the sensor according to Figure 7 and a cross-correlation function derived from it.

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

The Figure 1 shows an exemplary embodiment of a multi-unit vehicle according to the invention in the form of a railway train 10. The front car in the direction of travel F is formed by a locomotive 11; The remaining wagons can be freight wagons, for example. The last car is marked with the reference number 12.

A front sensor 21 is arranged on the locomotive 11, which measures a property dependent on the respective location of a route 30 being traveled over time, forming a first property curve EV1. The property can be, for example, a property of a rail on the route traveled, for example the permeability or roughness of the rail.

In the area of the last car 12 seen in the direction of travel F, a rear sensor 22 is arranged, which measures the same property as the front sensor 21 and detects a second property profile EV2.

An evaluation device 40 is connected to the first and second sensors, for example via radio, which in the exemplary embodiment according to Figure 1 is arranged in the locomotive 11; Alternatively, the evaluation device 40 could also be located in another car of the railway train 10.

An exemplary embodiment of an evaluation device 40 is shown in Figure 3 shown, so that with regard to the operation of the evaluation device 40 according to Figure 1 In the following, parallel reference is also made to the Figure 3 is taken.

The Figure 2 shows an example of the first and second property curves EV1 and EV2 over time t under the assumption that that the railway train 10 travels at a constant speed in the time window shown. It can be seen that the first property curve EV1 and the second property curve EV2 are offset in time or have a time gap; the time distance value dT is determined by a second time t2, at which the rear sensor 22 passes or has already passed a location previously passed by the front sensor 21, and a first time t1, at which the front sensor 21 has already passed the location mentioned, Are defined.

The evaluation device 40 evaluates the two property curves EV1 and EV2 by subjecting them to a correlation test; Such a correlation check can be carried out, for example, in a correlation module 41 (cf. Figure 3 ) of the evaluation device 40. As part of the correlation test, the correlation module 41 can, for example, form a cross-correlation function with the two property curves EV1 and EV2 and use this to determine the time offset or the time distance value dT.

On the basis of the time distance value dT, the evaluation device 40 subsequently calculates the length of the railway train 10, forming a length value LZ; For example, a multiplication module 42 of the evaluation device 40 can multiply the time distance value dT by a speed value V indicating the speed of the railway train 10 in order to calculate the length value LZ according to $$\mathrm{LZ}=\mathrm{v}\cdot \mathrm{dT}$$

A test module 43 (cf. Figure 3 ) the evaluation device 40 generates a train completeness signal Sv when the length value LZ corresponds to a predetermined target value LZsoll or at least does not deviate from it by more than a predetermined amount. If the length value LZ deviates from the target value LZsoll beyond the specified dimension, for example because a train has separated and the last car 12 is separated from the Locomotive 11 is disconnected, it generates an alarm signal Sa.

In connection with the Figure 2 The exemplary case was assumed that the railway train 10 travels at a constant speed, so that the sensors 41 and 42 each capture locally equidistantly sampled measured values at a constant temporal measurement frequency. However, in the event of speed fluctuations caused by accelerations or decelerations, stretches and compressions in the signal curve can occur. For example, in the case of an acceleration of a long train, the end of the train will pass a point that was previously passed by the head of the train at a significantly higher speed than the head of the train, so that - with a constant temporal sampling frequency - the measured values of the second property curve EV2 at this point continue locally lie apart than in the first property curve EV1; In the time domain this has the effect of signal compression.

In order to avoid the effect of signal distortion caused by acceleration, position pulse generators can be used, for example, which locally trigger the measurement recording. For example, the rotation of a wheel can be detected with a position pulse generator and a pulse can be generated each time a position increment of a predetermined length has been traveled. If the measurement resolution of the displacement pulse generator is sufficiently large, the measurement data acquisition for the property curves can be triggered directly via the pulses of such a displacement pulse generator, so that the measurements are no longer equidistant in time, but spatially equidistant over the distance traveled; With such locally equidistant measured value acquisition, vehicle accelerations have no influence on the property curves EV1 and EV2, so subsequent correction is not necessary.

The Figure 4 shows an example of location-related or distance-triggered measurement data acquisition over time t and over the location coordinate x. Controlled by the travel pulse generator When measuring measured values, local signal distortion is avoided; the temporal signal distortion that occurs is irrelevant.

Alternatively, in order to compensate for or avoid signal distortions, provision can be made to record the vehicle speed v(k) in addition to the actual measured value at each measurement time t(k). For a rail vehicle, the motion model with constant acceleration can be used at high sampling rates above 1kHz. The path increment s(k) covered between two measurements is given by: $$\mathrm{s}\left(\mathrm{k}\right)=\left(\mathrm{v}\left(\mathrm{k}\right)+\mathrm{v}\left(\mathrm{k}-1\right)\right)/2*\left(\mathrm{t}\left(\mathrm{k}\right)-\mathrm{t}\left(\mathrm{k}-1\right)\right).$$

The path is obtained by summing the path increments. If the measured signal is now displayed over the path, it is equalized, i.e. freed from acceleration and changes in speed.

The Figure 5 shows a preferred embodiment of the evaluation device 40 according to Figure 2 . The evaluation device 40 comprises a computing device 410 and a memory 420. A software program product SPM is stored in the memory 420, which, when executed by a computing device 410, causes it to carry out the functions of the evaluation device 40 described above.

The software program product SPM includes a correlation software module M41, which forms the above-described correlation module 41 when executed by the computing device 410, a multiplication software module M42, which forms the above-described multiplication module 42 when executed by the computing device 410, and a test module software module M43, which when executed by the Computing device 410 forms the test module module 43 described above.

The Figure 6 shows a further exemplary embodiment of a railway train 10 according to the invention. The railway train 10 according to Figure 6 corresponds to railway train 10 Figure 1 with the difference that a third sensor 23 is present, which measures the property dependent on the location of the route 30 being traveled over time, forming a third property curve EV3.

wobei ZV13 den Zeitversatz zwischen dem ersten Eigenschaftsverlauf EV1 und dem dritten Eigenschaftsverlauf EV3 bezeichnet.The third sensor 23 is arranged on the locomotive 11 and therefore has a small sensor distance LS from the front sensor 21 compared to the train length LZ, so that changes in speed do not lead to any relevant signal distortions. Based on the first and third property curves EV1 and EV3, the evaluation device 40 can determine the speed of the railway train 10 to form a speed value V by dividing the sensor distance LS by the time offset between the first property curve EV1 and the third property curve EV3 according to $$\mathrm{v}=\mathrm{L.S}/\mathrm{ZV}13$$

where ZV13 denotes the time offset between the first property curve EV1 and the third property curve EV3.

The speed value V can be used together with the first and second property curves EV1 and EV2 to calculate the length value LZ, as explained above. The time offset ZV13 can be determined in the same way as explained above in connection with the property curves EV1 and EV2 to determine the time distance value dT.

The Figure 7 shows an exemplary embodiment of a sensor 200, which can be used as a front sensor 21, rear sensor 22 or third sensor 23.

The sensor includes, among other things, an antenna 201, a mixer 202, a filter 203, an oscillator 204 and a transmit/receive switch 205. The antenna mounted on the railway train 10 201 emits a continuous wave microwave signal generated by the oscillator 204 at a predetermined angle. When it hits the ground, the signal is diffusely scattered by scattering bodies SK along the route 30. The backscattered signal components are superimposed on the antenna 201 and are mixed down with the transmission frequency into a baseband using the mixer 202 and then filtered using the filter 203. When stationary, there is a constant phase position; when driving, there is a relative movement of the scattering bodies SP to the antenna 201, as a result of which a continuous change in the phase position occurs. The Figures 8 and 9 show an example of the time course of the amplitude A(t) and the frequency course of the power density spectrum P(f) of a typical Doppler signal.

In Figure 10 The result of the cross-correlation K12(n) of two Doppler signals recorded one behind the other in the longitudinal direction of the vehicle (for the real part RT and imaginary part IT) is shown as an example over the sample values n. Local minima and maxima can be seen in the signal curves. In order to find the global maximum, it is advisable to create the envelope HK. The time interval dT can be determined using the envelope curve.

Finally, it should be mentioned that the features of all of the exemplary embodiments described above can be combined with one another in any way to form further other exemplary embodiments of the invention.

All features of subclaims can also be combined with each of the subordinate claims, each alone or in any combination with one or other subclaims, in order to obtain further other exemplary embodiments.

Claims (15)

Method for operating a multi-unit vehicle, in particular a railway train (10),
characterized in that - while the vehicle is traveling, a property dependent on the respective location of the route (30) being traveled is measured over time using a front sensor (21) arranged in the area of a front end of the vehicle, forming a first property curve (EV1), - while the vehicle is traveling, the property dependent on the respective location of the route (30) being traveled is measured over time using a rear sensor (22) arranged in the area of a rear end of the vehicle, forming a second property curve (EV2), - the first and second characteristic curves (EV1, EV2) are subjected to a correlation test to form a time distance value (dT), which is the time distance between a second point in time (t2) at which the rear sensor (22) receives a signal from the front sensor (21 ) has already passed or has already passed a location, and indicates a first time (t1) at which the front sensor (21) has already passed the location mentioned, and - the length of the vehicle is determined based on the time distance value (dT) to form a length value (LZ). Method according to claim 1,
characterized in that - a train completeness signal (Sv) is generated when the length value (LZ) corresponds to a predetermined target value (LZsoll) or at least does not deviate from it by more than a predetermined amount, and / or - an alarm signal (Sa) is generated when the length value (LZ) deviates from the specified target value (LZsoll) beyond the specified amount. Method according to one of the preceding claims,
characterized in that the correlation test includes determining a cross-correlation function (K12) with the first and second property curves (EV1, EV2) and determining the time distance value (dT) using the cross-correlation function (K12). Method according to one of the preceding claims,
characterized in that the formation of the length value (LZ) includes the multiplication of the time distance value (dT) by a speed value (V). Method according to one of the preceding claims,
characterized in that - the correlation test includes a correction of acceleration-related signal influences on the first and second property curves (EV1, EV2), - by spreading acceleration-related signal spreads over time on the computer side and compressing acceleration-related signal spreads on the computer side. Method according to one of the preceding claims,
characterized in that the property dependent on the respective location of the route (30) being traveled, which is measured by the front and rear sensors (21, 22), is a property of a radar reception signal that has penetrated a floor of the route (30) being traveled over. Method according to one of the preceding claims 1 to 5,
characterized in that the property dependent on the respective location of the route (30) being traveled, which is measured by the front and rear sensors (21, 22), is a property of a received Doppler signal from a constant wave radar, which also sends a radar signal at least in the direction of the ground of the route , is. Method according to one of the preceding claims 1 to 5,
characterized in that the property dependent on the respective location of the route (30) being traveled, which is measured by the front and rear sensors (21, 22), is a property of a magnetic field. Method according to one of the preceding claims 1 to 5,
characterized in that the property dependent on the respective location of the route (30) being traveled, which is measured by the front and rear sensors (21, 22), is the permeability of a rail on the route (30) being traveled. Method according to one of the preceding claims 1 to 5,
characterized in that the property dependent on the respective location of the route (30) being traveled, which is measured by the front and rear sensors (21, 22), is the roughness of a rail on the route (30) being traveled. Method according to one of the preceding claims,
characterized in that the measurement of the property measurements for the first and second property progression (EV1, EV2) takes place at fixed spatial distances. Method according to one of the preceding claims,
characterized in that - the correlation test includes a conversion of the first measured property curve (EV1) into a first speed-normalized property curve and a conversion of the second measured property curve (EV1) into a second speed-normalized property curve and - the correlation test also includes determining a cross-correlation function with the first and second speed-normalized property curves and to determine the time distance value (dT) using the cross-correlation function. Multi-part vehicle, in particular a railway train (10), characterized in that - a front sensor (21) is arranged in the area of a front end of the vehicle, which measures a property dependent on the respective location of a route (30) being traveled over time to form a first property curve (EV1), - A rear sensor (22) is arranged in the area of a rear end of the vehicle, which measures the property dependent on the respective location of the route (30) being traveled over time to form a second property curve (EV2), and - An evaluation device (40) connected to the first and second sensors (21, 22) is present, which - subjecting the first and second property curves (EV1, EV2) to a correlation test to form a time distance value (dT), which is the time distance between a second point in time (t2) at which the rear sensor (22) receives a signal from the front sensor (21). a location that has already happened or has happened before, and indicates a first time (t1) at which the front sensor (21) has already passed the location mentioned, and - the length of the vehicle is determined based on the time distance value (dT) to form a length value (LZ). Evaluation device (40) for a vehicle, in particular a vehicle according to claim 13,
characterized in that - the evaluation device (40) is designed to subject a first property curve (EV1), which was detected by a front sensor (21), and a second property curve (EV2), which was detected by a rear sensor (22), to a correlation test Formation of a temporal Distance value (dT), which is the time interval between a second time (t2), at which the rear sensor (22) passes or has already passed a location previously passed by the front sensor (21), and a first time (t1) , at which the front sensor (21) has already passed the location mentioned, and to determine the length of the vehicle on the basis of the time distance value (dT) to form a length value (LZ). Software Program Product (SPM),
characterized in that the software program product (SPM), when executed by a computing device (410), causes it to form an evaluation device (40) according to claim 14.

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