EP3782868A2 - Method for calibrating a speed sensor of a railway vehicle - Google Patents

Abstract

The invention relates to a method for calibrating a speed sensor (15) of a rail vehicle (10), a corresponding rail vehicle (10), a method for operating an axle counting system (20) for a rail vehicle (10), a corresponding axle counting system (20) and a method for Operating a rail vehicle (10). In the method, a measurement signal (v _A) provided via a transmission unit (22) is received, which is representative of a speed (v) of the rail vehicle (10) measured externally with respect to the rail vehicle; - a measured value (v _s) of the speed sensor (15) is provided, which is representative of a speed (v) of the rail vehicle (10) detected by the speed sensor (15); and - depending on the measurement signal (v _A) and the measurement value (v _s), a calibration coefficient (k) is determined and assigned to the speed sensor (15).

Description

A method for calibrating a speed sensor of a rail vehicle, a corresponding rail vehicle, a method for operating an axle counting system for a rail vehicle, a corresponding axle counting system and a method for operating a rail vehicle are specified.

Rail vehicles and other vehicles often include a variety of sensors for estimating a speed of the moving vehicle. In order to output a value of the speed that is as accurate as possible, some kind of calibration of the individual sensors is typically required. This calibration can be designed differently for each sensor. For example, in the case of a distance pulse generator that measures the number of revolutions of a vehicle wheel with a known circumference over a certain period of time and uses this to estimate the distance covered and the speed of the vehicle, an important parameter in the calibration is the circumference of the vehicle wheel, which changes over time. Up to now, this has required a trained technician who precisely measures the diameter of the vehicle wheel. However, errors in the measurement can occur here, which can be traced back to the technician or to different diameters of the vehicle wheel between individual measurements, which can be caused, for example, by intensive braking processes. As a result, the calibration requires the vehicle wheel to be measured as frequently and consistently as possible, which is associated with enormous effort and costs and at the same time requires the vehicle to be stationary.

document DE 27 41 883 A1 describes a distance and speed measuring device that uses a correction device in the vehicle. The correction device consists of a dividing circuit, a multiplying circuit and a Low pass filter. The dividing circuit divides the number of distance pulses supplied by a wheel-independent measuring system by the number of distance pulses supplied by a wheel-dependent measuring system. The division result is smoothed with the low-pass filter and then multiplied by a distance increment in the multiplication circuit.

A method for controlling a vehicle system in Document US 2014 0277 883 A1 comprises determining a vehicle reference speed using an off-board-based input speed and an on-board-based input speed. The off-board-based input speed is representative of a movement speed of the vehicle system and is determined from data received from an off-board device. The onboard-based input speed is representative of the speed of movement of the vehicle system and is determined from data obtained from an onboard device.

An object on which the invention is based is therefore to create a method for calibrating a speed sensor of a rail vehicle, a corresponding rail vehicle, a method for operating an axle counting system for a rail vehicle and a corresponding axle counting system through which or through which to a low-cost and inexpensive calibration can be contributed inexpensively. Another object on which the invention is based is to specify a method for efficiently operating a rail vehicle taking into account the aforementioned calibration.

The objects are achieved by the features of the corresponding independent patent claims. Advantageous configurations are characterized in the subclaims.

According to a first aspect, the invention relates to a method for calibrating a speed sensor of a rail vehicle in normal operation. The rail vehicle has a speed greater than 0 km / h in normal operation.

In the method, a measurement signal is received, which is provided via a transmission unit and which is representative of a speed of the rail vehicle measured externally with respect to the rail vehicle.

A measured value from the speed sensor is provided which is representative of a speed of the rail vehicle detected by the speed sensor.

Depending on the measuring signal and the measured value, a calibration coefficient is determined and assigned to the speed sensor.

The speed sensor is, in particular, an odometry sensor, such as a distance pulse generator or Doppler radar.

The transmitting unit is, in particular, a device, such as a balise, which is stationary, is arranged externally with respect to the rail vehicle and can be wirelessly coupled to a receiving unit of the rail vehicle.

By means of the method, in particular an existing infrastructure arranged on the rail network that is certified for rail vehicles can be used. Speed sensors can advantageously be calibrated without complex inspections by technicians and without putting the rail vehicle out of operation. Compared to other calibration techniques on the stationary rail vehicle, this type of calibration during operation of the rail vehicle is particularly advantageous in the case of sensors that are designed for higher speeds (e.g. a Doppler radar that is designed for speeds> 20 km / h) and behave differently when the rail vehicle is at a standstill. In addition, calibration can be carried out at short intervals without significant additional effort, in particular several times on a single journey of the rail vehicle. In this way, delays in the operation of the rail vehicle caused by incorrectly calibrated speed sensors can advantageously be avoided.

ermittelt, wobei β einen Gewichtungsfaktor mit einem Wert eines Bereichs [0; 1] und k_alt einen zuvor ermittelten Kalibrierungskoeffizienten bezeichnet.According to the invention, the calibration coefficient is according to $$k=\left(1-\beta \right)k_{\mathit{old}}+\beta \frac{v_{\mathrm{A.}}}{v_{\mathrm{S.}}}$$

is determined, where β is a weighting factor with a value of a range [0; 1] and k _old denotes a previously determined calibration coefficients.

In an advantageous embodiment according to the first aspect, the weighting factor is determined as a function of the speed of the rail vehicle.

ermittelt.In an advantageous embodiment according to the first aspect, the speed sensor is designed as a Doppler radar. The weighting factor is according to $$\beta \left(v_{\mathrm{A.}}\right)=\{\begin{array}{cc}\hfill 0& v_{\mathrm{A.}}<\mathrm{20th}\mathit{km}/H\\ \hfill 0,01& \mathrm{20th}\mathit{km}/H\le v_{\mathrm{A.}}\le 300\mathit{km}/H\\ \hfill 0& v_{\mathrm{A.}}>300\mathit{km}/H\end{array}$$

determined.

In an advantageous embodiment according to the first aspect, the rail vehicle has a plurality of speed sensors. In the method, a calibration coefficient is determined for each speed sensor as a function of the measurement signal and the respective measurement value and assigned to the corresponding speed sensor.

According to a second aspect, the invention relates to a rail vehicle.

The rail vehicle comprises a receiving unit for receiving a measurement signal provided by a transmitting unit. Furthermore, the rail vehicle comprises at least one speed sensor which is set up to detect a speed of the rail vehicle and to provide it as a measured value. Furthermore, the rail vehicle comprises a control unit, which is signal-coupled to the receiving unit and the at least one speed sensor and is set up to carry out the method according to the first aspect.

By means of the method, in particular the existing infrastructure of axle counting systems arranged on the rail network can be used for measuring and calibrating the speed of rail vehicles for which they were not originally intended. A calibration according to the first aspect can thus advantageously be implemented at extremely low costs.

According to a third aspect, the invention relates to a method for operating an axle counting system for a rail vehicle.

The axle counting system has a transmission unit, a first wheel sensor and a second wheel sensor. The first wheel sensor is arranged locally in front of the second wheel sensor at a predetermined distance in the direction of travel of the rail vehicle.

In the method, a first signal is provided by the first wheel sensor, which is representative of an impulse that is generated when a wheel of the rail vehicle passes the first wheel sensor.

A second signal is provided by the second wheel sensor, which is representative of an impulse which is produced when the wheel passes the second wheel sensor.

A time difference between the two pulses is determined as a function of the first signal and the second signal. Depending on the predetermined distance and the determined time difference, a speed of the rail vehicle is determined and transmitted as a measurement signal to a receiving unit of the rail vehicle by means of the transmitting unit.

According to a fourth aspect, the invention relates to an axle counting system for a rail vehicle.

The axle counting system comprises a transmitting unit for transmitting a measurement signal to a receiving unit of the rail vehicle. The axle counting system also includes a first wheel sensor for providing a first signal that is representative of an impulse that is generated when a wheel of the rail vehicle passes the first wheel sensor, and a second wheel sensor for providing a second signal that is representative of an impulse caused when the wheel passes the second wheel sensor. The first wheel sensor is arranged locally in front of the second wheel sensor at a predetermined distance in the direction of travel of the rail vehicle. The axle counting system further comprises a control device which is signal-technically coupled to the transmission unit, the first wheel sensor and the second wheel sensor and is set up to carry out the method according to the third aspect.

In a further advantageous embodiment according to the fourth aspect, the first wheel sensor and / or the second wheel sensor is or are designed as a double-sided sensor.

According to a fifth aspect, the invention relates to a method for operating a rail vehicle according to the second aspect with an axle counting system according to the fourth aspect.

The rail vehicle has a speed greater than 0 km / h. A wheel of the rail vehicle passes a first wheel sensor, a pulse being generated and a first signal being provided by the first wheel sensor to a control device of the axle counting system.

A second wheel sensor is passed with the wheel of the rail vehicle, a pulse being generated and a second signal being provided by the second wheel sensor of the control device. Depending on the first signal and the second signal, a time difference between the two pulses is determined by the control device and depending on a predetermined distance between the first wheel sensor and the second wheel sensor in the direction of travel of the rail vehicle and the determined time difference, a speed of the rail vehicle is determined by the control device. By means of the transmitting unit, the determined speed is transmitted as a measurement signal to a receiving unit of the rail vehicle.

The measurement signal is received by the receiving unit and provided to a control unit of the rail vehicle. A speed is recorded by a speed sensor of the rail vehicle and made available as a measured value to the control unit.

Depending on the measurement signal and the measurement value, a calibration coefficient is now determined by the control unit and assigned to the speed sensor. A calibrated speed of the rail vehicle is finally determined as a function of the calibration coefficient and the measured value.

In an advantageous embodiment according to the fifth aspect, the calibrated speed is according to $$v_{\mathrm{S.},k}=k\cdot v_{\mathrm{S.}}$$

Determined, where v _{S, k} denotes the calibrated speed.

In a further advantageous embodiment according to the fifth aspect, the rail vehicle has a plurality of speed sensors. In the method, a calibration coefficient is determined for each speed sensor as a function of the measurement signal and the respective measurement value and assigned to the corresponding speed sensor.

A respective calibrated speed of the rail vehicle is determined as a function of the respective calibration coefficient and the respective measured value. The speed of the rail vehicle is finally estimated as a function of all the calibrated speeds.

The above-mentioned properties, features and advantages of the invention and the manner in which they are achieved are explained in more detail by the following description of the exemplary embodiments of the invention in conjunction with the corresponding figures. Identical, identical or identically acting elements are provided with the same reference symbols in the figures. The figures and the proportions of the elements shown in the figures are not to be regarded as being to scale. Rather, individual elements can be shown exaggeratedly large for better illustration and / or for better understanding.

Figur 1

ein System zum Betreiben eines Schienenfahrzeugs;

Figur 2

ein Ablaufdiagramm eines Verfahrens zum Betreiben des Schienenfahrzeugs gemäß Figur 1; und

Figuren 3 und 4

jeweils ein Odometriesystem des Schienenfahrzeugs gemäß Figur 1.

Show it:

Figure 1

a system for operating a rail vehicle;

Figure 2

a flow chart of a method for operating the rail vehicle according to Figure 1; and

Figures 3 and 4

an odometry system of the rail vehicle in accordance with Figure 1 .

Based Figure 1 a system 100 for operating a rail vehicle 10 with an axle counting system 20 is shown. The rail vehicle 10 is operating as intended, in which it has a speed v > 0 km / h in the direction of travel (indicated here by the arrow).

The rail vehicle 10 comprises a control unit 11, an antenna as a receiving unit 12 for signaling coupling with a stationary transmitting unit 22 and several speed sensors 15, 16. The speed sensors 15, 16 can each be assigned to a wheel 13 of the rail vehicle 10, for example.

The axle counting system 20 is set up, for example, to determine status information about free or occupied track sections. In this context, the axle counting system 20 has a first wheel sensor 23, which is designed to detect a passage through a wheel and also as a counting head. "wheel detection equipment (WDE)" can be designated. For example, it is a wheel sensor that uses double-sided technology with two sensors, such as the "Clearguard ZP D 43" model from Siemens, which is already in considerable numbers (> 50,000) along the German rail network. This model includes a "DEK 43" unit as a double-sided sensor and uses an electromagnetic wheel detection process with a generator frequency of 43 kHz. When a wheel enters the detection range of the double-sided sensor, the strength of the electromagnetic alternating field changes and thereby generates signal pulses. These pulses are evaluated in the counting head. This information is transmitted to a control device 21, which is signal-coupled to the wheel sensor. The control device 21 is preferably arranged in the immediate vicinity of the first wheel sensor 23. The control device 21 can, however, also be arranged at a distance of up to 21 km from the first wheel sensor 23. The control device 21 can also be referred to as an evaluation device. The control device 21 is in particular a computer or an electrical circuit which is set up to receive signals, perform a calculation and send the result of the calculation in the form of an information packet.

The axle counting system 20 also has a second wheel sensor 24, which is located at a predetermined distance d in the direction of travel of the rail vehicle 10 is arranged to the first wheel sensor 23. The second wheel sensor 24 corresponds structurally and functionally in particular to the first wheel sensor 23. The axle counting system 20 usually includes the second wheel sensor 24 in order to be able to determine a direction of travel of a passing rail vehicle. The specified distance d of already installed wheel sensors of existing axle counting systems in this context is mostly between 20 cm and 80 cm inclusive (for slower or faster rail vehicles). Notwithstanding this, however, a different distance d is also conceivable.

A transmission unit 22 is also assigned to the axle counting system 20, which is connected to the control device 21 in terms of signaling and is set up for wireless communication with the receiving unit 12 of the rail vehicle 10. This is a balise or other device that is set up to transmit information to a rail vehicle driving over or passing nearby. In particular, the transmission unit 22 is an active or controllable balise. An active balise is, for example, connected to a so-called "lineside electronic unit", LEU. The LEU can, for example, be integrated into a signaling system, which in turn is integrated into a signal box in which the evaluation device is located.

The invention makes use of the knowledge that a large number of such axle counting systems are already installed along the rail network. In an advantageous manner, no or only minor structural changes are therefore required in order to implement the method described below.

The following explains how such an axle counting system 20 can be used to carry out a continuous calibration of speed sensors 15, 16 of the rail vehicle 10 during normal operation without having to rely on specially trained specialists or temporarily shut down the rail vehicle 10.

In this context, the control unit 11 and the control device 21 are each assigned a data and program memory, in each of which a program for the cooperative implementation of a method for operating the rail vehicle 10 is stored, which is based on the flowchart of FIG Figure 2 is explained in more detail below. The sequence of the individual program steps is only to be regarded as an example and may differ from the sequence described.

The program starts in a step S1 when the wheel 13 of the rail vehicle 10 passes the first wheel sensor 23. Here, a first signal is provided by the first wheel sensor 23 of the control device 21, which is representative of the impulse caused when passing. A first point in time t ₁ , which corresponds to the pulse, is determined by the control device 21 and the program is then continued in a step S2.

When the wheel 13 passes the second wheel sensor 24, a further pulse is generated and the control device 21 is provided with a second signal representative thereof by the second wheel sensor 24. In step S2, a second point in time t ₂ , which corresponds to the further pulse, is determined by the control device 21 and the program is then continued in a step S3.

ermittelt, das repräsentativ ist für eine Messung der Geschwindigkeit v des Schienenfahrzeugs 10 durch das Achszählsystem 20. Der vorgegebene Abstand d kann in diesem Zusammenhang beispielhaft in der Steuervorrichtung 21 hinterlegt sein, da er durch die Anordnung der Radsensoren 23, 24 konstant vorgegeben ist.In step S3, a time difference Δ t = t ₂ −t _{1 is} determined and a measurement signal is determined as a function of the predetermined distance d of the wheel sensors 23, 24 $v_{\mathrm{A.}}=\frac{d}{\mathrm{\Delta }\mathit{t}}$

which is representative of a measurement of the speed v of the rail vehicle 10 by the axle counting system 20. The predefined distance d in this context can be stored in the control device 21, for example, since it is constantly predefined by the arrangement of the wheel sensors 23, 24.

The calculation in step S3 is not very computationally intensive and could therefore be implemented, for example, by a dedicated circuit and can therefore be carried out particularly quickly. In the exemplary embodiment described here, the calculation is carried out in the control device 21, which usually already carries out similar calculation processes to determine the direction of travel and route occupancy, so that additional components can be dispensed with.

The method is then continued in a step S4, in which the measurement signal v _{A is} transmitted to the receiving unit 12 by means of the transmitting unit 22. Since rail vehicles are typically relatively long in comparison to a probable distance that a signal has to cover between wheel sensors 23, 24 and transmission unit 22, the measurement signal v _A can be transmitted without delay, in particular without buffering.

The method is then continued in a step S5, in which the measurement signal v _{A is received} by the receiving unit 12 and provided to the control unit 11 of the rail vehicle 10.

Thereupon, in a step S6, a measured value v _{S is} determined by the speed sensor 15, which is representative of a measurement of the speed v of the rail vehicle 10 by the rail vehicle 10 and provided to the control unit 11.

In a subsequent step S7, the calibration coefficient k for the speed sensor 15 is determined by comparing the measured value v _S with the measured signal v _A.

ermittelt.In a first embodiment, the calibration coefficient k is set according to $$k=\frac{v_{\mathrm{A.}}}{v_{\mathrm{S.}}}$$

determined.

iterativ ermittelt und erneuert. Hierbei bezeichnet k_alt den zuletzt ermittelten Kalibrierungskoeffizient und β einen Gewichtungsfaktor, welche die Lernrate berücksichtigt und einen Wert zwischen einschließlich 0 und einschließlich 1 annimmt, beispielsweise 0,01. Ein kleiner Wert für β reduziert hierbei insbesondere die Auswirkung eines einzelnen Messsignals v_A auf die Kalibrierung. Abweichend von den genannten Ausführungsvarianten sind auch andere Gewichtungs- oder Mischfunktionen denkbar.In a further embodiment, the calibration coefficient k is set according to $$k=\left(1-\beta \right)k_{\mathit{old}}+\beta \frac{v_{\mathrm{A.}}}{v_{\mathrm{S.}}}$$

iteratively determined and renewed. Here, k _old denotes the most recently determined calibration coefficient and β a weighting factor which takes the learning rate into account and assumes a value between 0 and 1 inclusive, for example 0.01. A small value for β in particular reduces the effect of an individual measurement signal v _A on the calibration. In a departure from the embodiment variants mentioned, other weighting or mixing functions are also conceivable.

gesetzt werden, um eine Kalibrierung außerhalb eines Geschwindigkeitsbereichs von 20 km/h bis 300 km/h zu unterbinden. Beispielhaft arbeitet der Doppler-Radar unterhalb von 20 km/h nichtlinear, während das Messsignal v_A des Achszählsystems 20 oberhalb von 300 km/h stark fehlerbehaftet ist. Die genannten Grenzen sind hierbei lediglich beispielhaft aufgeführt und können in der Praxis, insbesondere bei anderen Sensortypen stark hiervon abweichen. Indem der Gewichtungsfaktor β in Abhängigkeit des Messsignals v_A gesetzt wird, kann insbesondere eine Fehlfunktion der Messung des Achszählsystems 20 berücksichtigt werden, beispielsweise wenn das Messsignal v_A zu stark von dem Messwert v_S abweicht.Said weighting factor β can in particular be selected such that the calibration is carried out exclusively or preferably in a range of the speed v of the rail vehicle 10 in which the corresponding speed sensor 15 operates linearly or for which the speed sensor 15 is provided. For a Doppler radar, the weighting factor according to $$\beta \left(v_{\mathrm{A.}}\right)=\{\begin{array}{cc}\hfill 0& v_{\mathrm{A.}}<\mathrm{20th}\mathit{km}/H\\ \hfill 0,01& \mathrm{20th}\mathit{km}/H\le v_{\mathrm{A.}}\le 300\mathit{km}/H\\ \hfill 0& v_{\mathrm{A.}}>300\mathit{km}/H\end{array}$$

can be set to prevent calibration outside a speed range of 20 km / h to 300 km / h. For example, the Doppler radar works non-linearly below 20 km / h, while the measurement signal v _{A of} the axle counting system 20 is highly error-prone above 300 km / h. The limits mentioned are only listed as examples and can differ greatly in practice, especially with other sensor types. By setting the weighting factor β as a function of the measurement signal v _A , a malfunction in the measurement of the axle counting system 20 can in particular be taken into account, for example if the measurement signal v _A deviates too much from the measurement value v _S.

The calibration coefficient k is assigned to all subsequent measurements of the speed sensor 15, for example until a new calibration is carried out. For this purpose, in a step S8 following step S7, a calibrated speed v _{S, k} = k · v _{S is} determined. Even if a calibration is faulty, a new calibration can take place during the operation of the rail vehicle 10.

Before the first calibration, that is to say before the axle counting system 20 is passed for the first time, the calibration coefficient k = 1.

Steps S1 to S4 are carried out in particular by the control device 21 of the axle counting system 20 and, for example, form a separate computer program. Steps S5 to S8 are carried out in particular by the control unit 11 of the rail vehicle 10 and, for example, also form a separate computer program.

Steps S1 to S8 can be carried out again for each additional wheel 14 of the rail vehicle 10 detected by the axle counting system 20. Alternatively or additionally, after providing a single measurement signal v _A, steps S5 to S8 can be carried out for each further speed sensor 16 of the rail vehicle 10 based on the single measurement signal v _A and the respective measurement value v _S. In this context, as shown by way of example, only one control unit 11 is assigned to the rail vehicle 10. Notwithstanding this, it is also conceivable to carry out steps S5 to S8 for each speed sensor 15, 16 on a separate control unit 11.

For example, several speed sensors 15, 16, 17 form an odometry system 19 of the rail vehicle 10 (see FIGS. 3 and 4).

How based on Figure 3 As shown, the odometry system 19 has a fusion unit 18 which is composed of several measured values v _S1 - v _{S3 of} the individual speed sensors 15, 16, 17 determine the estimated speed v _{est of} the rail vehicle 10. Because the speed sensors 15, 16, 17 are not calibrated or are incorrectly calibrated, the speed v _est estimated by this odometry system 19 typically has an error between 2-4% of the actual speed v , which, among other things, can lead to delays in the operation of the rail vehicle 10.

In contrast to the odometry system 19, the proposed system 100 can supply calibrated speeds v _{S, k 1} -v _{S, k 3} to the fusion unit 18, so that a more precise estimated speed v _{est of} the rail vehicle 10 is contributed. Deviating from the representation of the odometry system 19, it is particularly conceivable here to form the control unit 11 in a structural unit with the fusion unit 18.

Although the invention has been illustrated and described in detail on the basis of exemplary embodiments, the invention is not restricted to the disclosed exemplary embodiments and the specific combinations of features explained therein. Further variations of the invention can be obtained by one skilled in the art without departing from the scope of the claimed invention.

List of reference symbols

100

system

10

Rail vehicle

11

Control unit

12

Receiving unit

13

wheel

15th

Speed sensor

16, 17

further speed sensors

18th

Fusion unit

19th

Odometry system

20th

Axle counting system

21st

Control device

22nd

Sending unit

23

first wheel sensor

24

second wheel sensor

d

distance

v

speed

v _S

Measured value

v _A

Measurement signal

v _{S, k}

calibrated speed

v _est

estimated speed

k

Calibration coefficient

S1-S9

Program steps

Claims (11)

Method for calibrating a speed sensor (15) of a rail vehicle (10) in normal operation, the rail vehicle (10) having a speed ( v ) greater than 0 km / h in normal operation, and in the case of the method: - A measurement signal (v _A ) provided via a transmission unit (22) is received, which is representative of a speed (v ) of the rail vehicle (10) measured externally with respect to the rail vehicle (10), - A measured value ( v _S ) of the speed sensor (15) is provided which is representative of a speed ( v ) of the rail vehicle (10) detected by the speed sensor (15), and - Depending on the measurement signal ( v _A ) and the measured value ( v _S ), a calibration coefficient (k) is determined and assigned to the speed sensor (15). - the calibration coefficient (k) according to $$k=\left(1-\beta \right)k_{\mathit{old}}+\beta \frac{v_{\mathrm{A.}}}{v_{\mathrm{S.}}}$$

is determined, where β is a weighting factor with a value of a range [0; 1] and k _old denotes a previously determined calibration coefficients. Method according to Claim 1, in which the weighting factor β is determined as a function of the speed ( v ) of the rail vehicle (10). Method according to Claim 1 or 2, in which the speed sensor (15) is designed as a Doppler radar and the weighting factor β according to $$\beta \left(v_{\mathrm{A.}}\right)=\{\begin{array}{cc}\hfill 0& v_{\mathrm{A.}}<\mathrm{20th}\mathit{km}/H\\ \hfill 0,01& \mathrm{20th}\mathit{km}/H\le v_{\mathrm{A.}}\le 300\mathit{km}/H\\ \hfill 0& v_{\mathrm{A.}}>300\mathit{km}/H\end{array}$$

is determined. Method according to one of the preceding claims, wherein the rail vehicle (10) has a plurality of speed sensors (15, 16) in which - a calibration coefficient (k) for each speed sensor (15, 16) is determined as a function of the measurement signal ( v _A ) and the respective measured value ( v _S ) and is assigned to the corresponding speed sensor (15, 16). Rail vehicle (10), comprising - a receiving unit (12) for receiving a measurement signal ( v _A ) provided by a transmitting unit (22), - At least one speed sensor (15, 16) which is set up to detect a speed (v ) of the rail vehicle (10) and to provide it as a measured value ( v _S ), and - A control unit (11) which is signal-technically coupled to the receiving unit (12) and the at least one speed sensor (15, 16) and is set up to carry out the method according to one of the preceding claims. Method for operating an axle counting system (20) for a rail vehicle (10) with a transmitter unit (22), a first wheel sensor (23) and a second wheel sensor (24), the first wheel sensor (23) locally in the direction of travel of the rail vehicle (10) is arranged in front of the second wheel sensor (24) at a predetermined distance ( d ), and in the method - A first signal is provided by the first wheel sensor (23), which is representative of an impulse which is generated when a wheel (13) of the rail vehicle (10) passes the first wheel sensor (23), - A second signal is provided by the second wheel sensor (24), which is representative of an impulse which is produced when the wheel (13) passes the second wheel sensor (24), a time difference between the two pulses is determined as a function of the first signal and the second signal, and - Depending on the predetermined distance ( d ) and the determined time difference (Δ t ), a speed ( v ) of the rail vehicle (10) is determined and transmitted by means of the transmitting unit (22) to a receiving unit of the rail vehicle (10) as a measurement signal ( v _A ) for performing a method according to one of Claims 1 to 4. Axle counting system (20) for a rail vehicle (10) comprising - a transmitting unit (22) for transmitting a measurement signal ( v _A ) to a receiving unit (12) of the rail vehicle (10), - A first wheel sensor (23) for providing a first signal which is representative of an impulse which is generated when a wheel (13) of the rail vehicle (10) passes the first wheel sensor (23), - A second wheel sensor (24) for providing a second signal which is representative of an impulse which is generated when the wheel (13) passes the second wheel sensor (23), the first wheel sensor (23) in the direction of travel of the rail vehicle (10) is arranged locally in front of the second wheel sensor (24) at a predetermined distance ( d ), and - A control device (21) which is signal-technically coupled to the transmitting unit (22), the first wheel sensor (23) and the second wheel sensor (24) and is set up to carry out the method according to claim 6. Axle counting system (20) according to claim 7, wherein the first wheel sensor (23) and / or the second wheel sensor (24) is or are designed as double-sided sensors. Method for operating a rail vehicle (10) according to claim 5 with an axle counting system (20) according to claim 7 or 8, wherein - the rail vehicle (10) has a speed ( v ) greater than 0 km / h, - A first wheel sensor (23) is passed with a wheel (13) of the rail vehicle (10), a pulse being generated and a first signal being provided by the first wheel sensor (23) of a control device (21) of the axle counting system (20), - A second wheel sensor (24) is passed with the wheel (13) of the rail vehicle (10), a pulse being generated and a second signal being provided by the second wheel sensor (24) of the control device (21), - Depending on the first signal and the second signal, a time difference between the two pulses is determined by the control device (21) and depending on a predetermined distance ( d ) between the first wheel sensor (23) and the second wheel sensor (24) in the direction of travel of the rail vehicle ( 10) and the determined time difference (Δ t ) a speed ( v ) of the rail vehicle (10) is determined by the control device (21) and by means of the transmitting unit (22) of a receiving unit (12) of the rail vehicle (10) as a measurement signal ( v _A ) is transmitted, - the measurement signal ( v _A ) is received by the receiving unit (12) and provided to a control unit (11) of the rail vehicle (10), - a speed ( v ) of the rail vehicle (10) is detected by a speed sensor (15) and made available as a measured value ( v _S ) to the control unit (11), - Depending on the measurement signal ( v _A ) and the measurement value ( v _S ), a calibration coefficient (k) is determined by the control unit (11) and assigned to the speed sensor (15), - the calibration coefficient (k) according to $$k=\left(1-\beta \right)k_{\mathit{old}}+\beta \frac{v_{\mathrm{A.}}}{v_{\mathrm{S.}}}$$

is determined, where β is a weighting factor with a value of a range [0; 1] and k _alt denotes a previously determined calibration coefficient and - A calibrated speed v _{S, k of} the rail vehicle (10) is determined as a function of the calibration coefficient (k) and the measured value ( v _S). Method according to claim 9, wherein the calibrated speed v _{S, k} according to $$v_{\mathrm{S.},k}=k\cdot v_{\mathrm{S.}}$$

is determined. Method according to one of the preceding claims 9 and 10, wherein the rail vehicle (10) has a plurality of speed sensors (15, 16) in which - a calibration coefficient (k) for each speed sensor (15, 16) is determined as a function of the measurement signal ( v _A ) and the respective measured value ( v _S ) and is assigned to the corresponding speed sensor (15, 16), - a respective calibrated speed v _{S, k of} the rail vehicle (10) is determined as a function of the respective calibration coefficient (k) and the respective measured value ( v _{S), and} - The speed ( v ) of the rail vehicle (10) is estimated as a function of all the calibrated speeds v _{S, k.}

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