EP1418109B1 - Position and speed determination method - Google Patents

Abstract

A rail vehicle position (P1, P2) and speed measurement procedure obtains values from at least two different independent procedures (A11, A12; A21, A22) with different power supplies and different locations using majority voting with statistical processing (B1, B2) to produce true outputs (MW1, MW2) with status signals.

Description

The present invention relates to a method for position and velocity determination according to the preamble of patent claim 1.

Due to the increasing traffic density and unfortunately also due to accidents further developments of train control systems have been made. In particular, in order to be able to lead trains without locomotive changes across national and rail administration, the expiry of many national systems, in particular on main lines, is already planned. These systems are successively replaced by a standardized "European Train Control System" - hereinafter referred to as ETCS. The ETCS offers significantly increased train control functionality compared to legacy systems and significantly improves security. An overview of the existing train control systems as well as the replacement strategy by ETCS is given in the publication ETR Heft 11/2000 [1]. The technical specification of the ETCS is contained in the relevant UNISIG documents [2].

In the UK, rail authorities use a Train Protection and Warning System (TPWS), which uses signal words such as "WARNING", "SPEED WARNING" or "HALT" in the frequency range of a few tens of kHz in pairs from 10 to 22 m apart "can be transmitted to a vehicle driving over these devices. The speed monitoring is performed by a time measurement between the signals received from two transmission devices of a pair. This means that with the same equipment on the one hand, all trains are monitored to the same maximum speed and on the other hand, that over the distance of this group, the speed is determined. amendments require either a new installation on the track or a reconfiguration of the transmission equipment on site.

The document WO 01/89904 A1 [3] discloses an apparatus and a method with which the position of a train is determined by a comparison of previously stored route values with the route values registered during a journey. The mentioned distance values represent e.g. Parameters for a curve or line-specific irregularities. In the event of sudden or gradual changes to the route, this method requires a new acquisition of the previously stored route values. In addition, the obtained position data is not trusted enough to make security-related decisions based thereon, such as e.g. Ride at a certain speed - to hit.

According to the teaching in document WO 02/058984 A1 [4], recording data for compensating for changing recording data is filtered, and recording data present as position data are thereby adaptively improved.

With the upgrading of the railways to state-of-the-art train control procedures at a uniform international level (interoperability), the facilities operating on the vehicles are no longer sufficient for determining the position and speed. For these new methods, it is necessary to know the absolute position of a vehicle and its instantaneous speed accurately and reliably at any time in accordance with a required SIL value. The meaning of SIL (Safety Integrity Level) values is defined in EN 50126 [5], EN 50129 [6] and IEC 61508 [7].

The document DE 195 32 104 C1 [8] discloses a method for determining the position of a track-guided vehicle, in which three types of independently obtained position measurement data such as object location, path length and route are obtained and through a correlation with a correlation of stored target data position over a Mn decision making process is determined.

The object of the present invention is therefore to improve the method disclosed in [8] on the basis of independently obtained position data types. The process should be easy to install and implement and, if possible, to rely on existing in-vehicle method for position and speed measurement.

This object is achieved by the measures specified in claim 1.

By the method steps specified in claim 1 it is ensured on a rail vehicle that a safety-critical decision can be made with the thus determined position and speed values. By means of the status signal or attribute itself generated by the measuring method, an associated measured value can be discarded if necessary. The independence of the measuring methods used includes, for example, the isolated effect of interferences or the limited error propagation of an endogenous error in the various functional blocks when carrying out the method according to the invention.

Advantageous embodiments of the invention are specified in further claims.

1. i) Dadurch dass
   «im Verfahrensschritt A die gewonnenen Messwerte einer Korrelationsbestimmung unterzogen werden und bei einer zu geringen Korrelation das betreffende Statussignal einen ungültigen Messwert anzeigt»;
   können übergrosse Abweichungen bereits durch das Messverfahren selber erkannt werden und eine Entscheidung über die Ungültigkeit eines Messwertes bereits vor der Auswertung erkannt und signalisiert werden. (Patentanspruch 3).
2. ii) Dadurch dass
   «im Verfahrensschritt A die Messverfahren je eine eigene Zeitbasis aufweisen»;
   können auch zwei gleiche unabhängig voneinander erfasste Messgrössen verschiedener Quellen zur Bestimmung eines Lageoder Geschwindigkeitswertes herangezogen werden
   (Patentanspruch 4).
3. iii) Dadurch dass
   «im Verfahrensschritt B wenigstens eine Auswerteeinheit alternativ als 2v2- oder 2v3-Auswertesystem ausgebildet ist»;
   können die wenigstens zwei Messwerte zuverlässig zur Bestimmung des «wahren» Lage- oder Geschwindigkeitswertes herangezogen werden (Patentanspruch 6).
4. iv) Dadurch dass
   «die Auswerteeinheiten und Funktionsblöcke, in denen die Messverfahren implementiert sind, je eine separate Energieversorgung aufweisen»;
   ist auf einem Triebfahrzeug sichergestellt, dass bei Auftreten eines Energiezuführungsunterbruches die einzelnen funktional verbleibenden Einheiten eine Fortführung des Betriebs mit einem reduzierten SIL-Level ermöglichen (Patentanspruch 8).
5. v) Dadurch dass
   «die Auswerteeinheiten und die Funktionsblöcke an verschiedenen Orten innerhalb eines Schienenfahrzeuges oder eines Eisenbahnzuges installiert sind»;
   sind die betreffenden Einheiten in unterschiedlichem Ausmass der gleichen Störbeeinflussung ausgesetzt und dadurch weisen die bestimmten Lage- und Geschwindigkeitswerte eine höhere Vertrauenswürdigkeit und geringere Abweichung zum tatsächlichen Wert auf, da sie nicht systematisch beeinträchtigt sind (Patentanspruch 9).

This may result in the following additional benefits:

1. i) By that
   «In the method step A, the measured values obtained are subjected to a correlation determination and, if the correlation is too low, the relevant status signal indicates an invalid measured value»;
   Excessive deviations can already be detected by the measuring method itself and a decision on the invalidity of a measured value can already be recognized and signaled before the evaluation. (Claim 3).
2. ii) By that
   «In method step A, the measuring methods each have their own time base»;
   It is also possible to use two identical measured quantities of different sources independently of one another for determining a position or velocity value
   (Claim 4).
3. iii) By that
   In method step B, at least one evaluation unit is alternatively designed as a 2v2 or 2v3 evaluation system »;
   For example, the at least two measured values can be reliably used to determine the "true" position or speed value (claim 6).
4. iv) By that
   «The evaluation units and function blocks in which the measuring methods are implemented each have a separate power supply»;
   is ensured on a traction unit that when a power supply interruption, the individual functionally remaining units allow a continuation of the operation with a reduced SIL level (claim 8).
5. v) By that
   "The evaluation units and the function blocks are installed at different locations within a rail vehicle or a railway train";
   If the units in question are subject to the same degree of interference to varying degrees, the determined position and speed values are more reliable and less deviating from the actual value because they are not systematically affected (claim 9).

Since the location of the device for obtaining the current position and velocity values from the data output by the transducers can be made at least partially physically in the device for method step B in a 2v2 or 2v3 evaluation system, significant hardware and hardware savings are thus possible with the costs.

Figur 1

Funktionsblöcke und Auswerteeinheiten mit den Datenflüssen zur Bestimmung sicherer Lage- und Geschwindigkeitswerte.

The invention will be explained in more detail with reference to the drawing, for example. Showing:

FIG. 1

Function blocks and evaluation units with the data flows for determining safe position and speed values.

P11:

Skalare Grösse:

• Winkelgeschwindigkeit eines nicht angetriebenen und nicht bremsbaren Laufrades eines Zuges;

P12:

2-tupel:

• Abstand a eines Balisenpaares des Systems Eurobalise und gemessene Zeitdifferenz Δt, P12 := P12(a, Δt), der Abstand a wird dabei auch zum Triebfahrzeug übermittelt;

P21:

2-tupel:

• Streckenkennung id und Wegmarke s auf dieser Strecke aus einem Zugsicherungssystem, z.B. Eurobalise, P21 := P21(id, s);

P22:

3-tupel:

• Geographische Koordinaten und Zeit aus einem Ortungs-system, z.B. Positionierungssystem "Galileo" (euro-päisch) oder GPS/DGPS/EGNOS (US) oder GLONAS (RU).

Figure 1 shows the basic arrangement of the functional blocks for the inventive method for position and speed measurement. With the reference symbols P11, P12, P21 and P22 different physical quantities are shown, which with the sensors S11, S12, S21 and S22 are detected. These physical quantities represent a quantity v or 1, which contain the speed or the position of a railway train A11, A12, A21 and A22. The aforementioned sensors S11, .., S22 are each connected to a functional block A11, A12, A21 and A22. Each of these functional blocks contains an implementation of a (measurement) method for measuring the physical quantities P11,.., P22. These sizes can be scalars, n-tuples, or vectorial sizes. The following does not strictly distinguish between the measuring method A _ij and the associated function _block A _ij . In this embodiment, it is assumed that the speed v of a train is determined from the above-mentioned quantities P11 and P12 by the methods to be explained. In this embodiment, the identifiers P11, .., P22 are assigned the following assignment or meaning by way of example:

P11:

Scalar size:

• Angular velocity of a non-driven and non-brakable impeller of a train;

P12:

2-tuple:

• Distance a of a pair of balises of the system Eurobalise and measured time difference Δt, P12: = P12 (a, Δt), the distance a is transmitted to the locomotive;

P21:

2-tuple:

• Route identifier id and waymark s on this route from a train protection system, eg Eurobalise, P21: = P21 (id, s);

P22:

3-tuple:

• Geographical coordinates and time from a positioning system, eg positioning system "Galileo" (Euro-Päisch) or GPS / DGPS / EGNOS (US) or GLONAS (RU).

1. i) Geschwindigkeitsbestimmung durch Aussenden eines Signals im Ultraschallbereich und Messung des reflektierten Signals unter Berücksichtigung des Doppler-Effektes;
2. ii) Aus einem in einem Triebfahrzeug enthaltenen Beschleunigungsmesssystem wird durch Integration über die Zeit die Geschwindigkeit v und ein Lagewert 1 bestimmt.
3. iii) Mittels spezieller Transponder längs einer Strecke sind Wegmarken definiert, die vom System Eurobalise unabhängig sind. Daraus werden je nach Implementation relative oder absolute Lagewerte 1 bestimmt.

The aforementioned assignment to the physical quantities is only an example, further examples are in non-exhaustive list:

1. i) speed determination by emitting a signal in the ultrasonic range and measuring the reflected signal taking into account the Doppler effect;
2. ii) From an acceleration measuring system contained in a traction vehicle, the speed v and a position value 1 are determined by integration over time.
3. iii) By means of special transponders along a route, route marks are defined that are independent of the Eurobalise system. From this, depending on the implementation, relative or absolute position values 1 are determined.

For the purposes of this document, instead of the term position value 1, the term position indication or way value is used synonymously. The term position value has a broader meaning than the term way value, since a way value is always defined only in connection with a predetermined route or a predetermined rail track.

A preferred embodiment of the present invention is based on a SIL level 3 basis. A SIL level 3 means that every 10 ⁷ to 10 ⁸ hours of operation on a function, that is to say the observation unit, is to be reckoned with an uncontrollable error which can then pose a serious threat to man and material.

According to the following embodiment, P1 represents a real speed value and P2 represents a real position, while the measured value M11 or M12 represents a measured value of the real speed value M1 or v obtained with the measuring method A11 or A12. This notation also applies accordingly to the position specification.

In a method step A, a position specification and a speed value are each obtained on two different measuring methods.

Measuring method A11 for a speed value P1:

From the "Eurobalise" system, a speed value is determined from pairs of balises arranged over defined distances. The reference P1 thus represents the distance of a pair of balises as well as the measured time difference .DELTA.t, which is measured when passing over such a pair of balises and wherein the distance a and the time difference At are transmitted to the vehicle. The system Eurobalise uses its own time base. The speed value M11 obtained in this way is based on a clocked method. The clock is given by the arrangement of Balisenpaare and the average speed of the train between two Balisenpaaren.

Measuring method A12 for a speed value P1:

From a non-driven axle of a modern railway train (for example, ICN SBB AG) is determined by a rotary incremental encoder speed and thus the known radius of the wheel, the rotational speed. Function block A12 has its own time base. The speed value M12 obtained in this way is based on a quasi-continuous method.

Measuring method A21 for a position indication P2:

By means of path marks arranged along a path, an absolute position indication P2 of a vehicle is determined. Since the relative location of the detection device must be taken into account within the train concerned, such detection devices are preferably arranged at the top of the relevant train (traction vehicle, control car).

Measurement method A22 for a position indication:

From a location system, the geographical coordinates and time are determined. For the geographical coordinates, a transformation into the customary representation can already be anticipated, e.g. into the coordinates of the Swiss land topography L + T.

To further ensure the independence of the measuring methods A11, A12, A21 and A22, their units A11, A12, A21 and A22 are supplied with energy by mutually independent supplies. In a preferred embodiment, these units are moreover arranged at electrically and locally different locations of the railway train. This gives the effect that the same disturbance, e.g. by an electromagnetic field, to which units do not have the identical effects. This interference may well have their origin in the vehicle and may also affect the conduction of the function of the aforementioned units. In terms of the maximum dependence of the measurement methods considered or their functional blocks, the so-called EMC interference can not be warded off alone with immunity measures. Therefore, the distributed arrangement in a vehicle is of particular importance.

• Temperatur ausserhalb eines definierten Intervalls,
• Langzeiteinwirkung der Erschütterung,
• Langzeiteinwirkung von Umwelteinflüssen wie Feuchtigkeit, Schmutz.
• Verfrachtung von festen oder flüssigen Stoffen im Gleis bereich wie Schnee, Sand, Wasser und dergleichen durch Witterung und/oder Befahrung.

Further examples of the interference are:

• Temperature outside a defined interval,
• Long-term effect of vibration,
• Long-term effect of environmental influences such as moisture, dirt.
• Transport of solid or liquid materials in the track area such as snow, sand, water and the like by weathering and / or driving.

• fragliche Plausibilität;
• Systemzustand (System hinsichtlich der Komponenten des Messverfahrens) aufgrund von Protokollen in einer Logdatei;
• Neustart/Reboot des Messverfahrens seit der letzten Übermittlung eines Messwertes.

The obtained measured values become provided with further information: The measured values M11, .., M22 originating from the measuring methods A11, .., A22 are provided by the measuring method itself with a status signal S11,..., S22, also called an attribute. Such a status signal S _xy may contain information about the measured value M _xy and its history such as, for example

• questionable plausibility;
• System state (system with regard to the components of the measurement method) due to logs in a log file;
• Restart / reboot the measurement since the last transmission of a measurement.

• Ein 2v2-Auswertesystem beinhaltet die Verfahrensschritte:
  • Es wird auf Gleichheit der Messwerte, hier der Eingangsmesswerte M11 und M12 bzw. M21 und M22 innerhalb einer vorgegebenen Toleranz geprüft. Bei Gleichheit wird der entsprechende «wahre» Messwert MW1 bzw. MW2 durchgeschaltet. Darüber hinaus kann ein zugehöriges Status-oder Lesesignal St1 bzw. St2 erzeugt werden. Das Statussignal St1 bzw. St2 beinhaltet die Information, dass der am Auswerteeinheit B1 bzw. B2 anliegende Wert zum betrachteten Zeitpunkt gültig ist.

The evaluation of the measured values takes place in a respective evaluation unit B1 or B2, which is designed for example as a 2v2 evaluation system or as a 2v3 evaluation system:

• A 2v2 evaluation system contains the process steps:
  • It is checked for equality of the measured values, here the input measured values M11 and M12 or M21 and M22 within a specified tolerance. If equal, the corresponding "true" measured value MW1 or MW2 is switched through. In addition, an associated status or read signal St1 or St2 can be generated. The status signal St1 or St2 contains the information that the value applied to the evaluation unit B1 or B2 is valid at the time in question.

Instead of the 2v2 evaluation system, a 2v3 evaluation system can also be used. Here, three "equal" input quantities are used to determine a true position or velocity value; If, of these 3 input quantities, the two of them match within a tolerance band, the two values are the basis for determining the "true" measured value MW1 or MW2.

Alternatively, a static method for determining the position or speed can be used for the aforementioned 2v2 or 2v3 evaluation systems. For determining the position, it must be checked whether the individual position values represent a monotonous or strictly monotonous growing number sequence. The distinction "monotone" or "strictly monotonic" depends on the presence of a signal indicating the stoppage of a train. Since speed value and position value are dependent variables over time, the static method can also include an integration of the speed over time and the integral value can be compared with the position value to be checked, just to check the plausibility. An equality in a certain tolerance band does not indicate the correctness of the determined values, but the inequality provides a statement that one of the considered values has an intolerable error. It is a matrix with the dependencies resp. to create and evaluate the independence.

Since the measuring methods A _{ij have} a functional relationship directly with the sensors S _ij , it is also possible to subject the measured values M _{ij to} a correlation determination. This can be done on the one hand between the two measuring methods Ai1 and Ai2 and on the other hand for a series of measurements (M _ij ) of the same size P _ij . Compared with the application of a static method in the evaluation unit B1 or B2, this correlation determination can be made smaller time intervals, this is particularly useful when a continuous or quasi-continuous size P _{ij is} measured.

Instead of the respectively provided for position and speed determination evaluation units B1 and B2, a single evaluation unit can be provided.

In particular for closed train units, e.g. the ICN tilting trains of the Swiss Federal Railways SBB, the inventive method distributed to several cars can be implemented. The transmission of the method according to the invention can be transmitted to a central point in the tilting train to increase the independence and reliability against interference on various wired and / or radio-controlled bus systems.

The above explanations have been given as examples to ensure independence and integrity. For the purposes of the teaching according to the invention, further constructive, metrological and circuit measures may alternatively or cumulatively be provided in order to further increase the abovementioned independence and reliability of the position and speed values determined in this way.

List of reference numbers and abbreviations used

A11, A12

Function block, measuring method for determining measured values M11 and M12, e.g. speed

A21, A22

Function block, measuring method for determining the measured values M21 and M22, e.g. location

B1

Evaluation unit for the measured values M11 and M12

B2

Evaluation unit for the measured values M21 and M22

P11, P12

physical quantity, each representing a speed of a vehicle

P21, P22

physical size, each representing a position of a vehicle

M11, M12

measured values determined by the measuring method A11 or A12, here speed value

M21, M22

Measured values determined by measuring method A21 or A22, here position indication

MW1 "

true "measured value determined from the quantities P11, P12

MW2

"true" measured value determined from the sizes P21, P22

S11, S12

Sensor for the detection of physical size P11 or P12

S21, S22

Sensor for the detection of physical size P21 or P22

St11, St12

Attribute for the measured value M11 or M12

St21, St22

Attribute for the measured value M21 or M22

a

Distance of a balise pair

.delta.t

measured time difference

l

position value

v

speed value

DGPS

Differential GPS

EGNOS

European Geostationary Navigation Overlay Service

ETCS

European Train Control System

GPS

Global Positioning System

SIL

Safety Integrity Level

RU

Russia

US

United States of America

List of quoted writings

1. [1] ETR issue 11/2000, p. 725 to 733 "train control systems of European railways"; Prof. Dr. Jörn Pachl.
2. [2] UNISIG SRS, SUBSET-026, Version 2.0.0 dated 22.12.1999.
3. [3] WO 01/89904 A1
   «Method and device for determining a parameter for a rail-bound vehicle», Daimler Chrysler Rails Systems GmbH, Berlin.
4. [4] WO 02/058984 A1
   «Method and device for determining the current position and for monitoring the planned path of an object», Bombardier Transportation GmbH, Berlin.
5. [5] EN 50126
   European Standard, September 1999 Railway applications - Specification and proof of reliability, availability, maintainability and safety (RAMS).
6. [6] EN 50129
   European Standard, September 2002 Railway applications - Telecommunications, Signaling and Data Processing - Security-relevant electronic signaling systems
7. [7] IEC 61508
   International Standard, December 1998 Parts 1 to 7 Functional safety of electrical / electronic / programmable electronic safety-related systems
8. [DE] EN 195 32 104 C1
   «Method and device for determining the position of at least one location of a track-guided vehicle», Daimler-Benz Aktiengesellschaft, 70567 Stuttgart.

Claims (9)

1. Method for determining the position and speed of a rail-mounted vehicle, with

   A position and speed values (P1, P2) each being obtained from at least two different mutually independent measuring methods (A11, A12; A21, A22),

   B the measurement values (M11, M12; M21, M22) representing the position and the speed and obtained in method step A are fed to an evaluation unit (B1, B2), in which the position and speed are determined (MW1, MW2),

   characterised in that
   in method step A, the measuring methods (A11, A12; A21, A22) each generate a status signal (St11, St12, St21, St22) in addition to the measurement values (M11, M12, M21, M22), said status signal indicating the validity of the generated measurement value (M11, M12, M21, M22) and the status signals (St11, St12, St21, St22) are fed to the evaluation unit (B1, B2).
2. Method according to claim 1,
   characterised in that
   the status signal (St11, St12, St21, St22) contains the following data:

   - questionable plausibility and/or

   - system status based on protocols in a log file and/or

   - re-start/reboot of the measuring method since the last transmission of a measurement value.
3. Method according to claim 1 or 2,
   characterised in that
   the obtained measurement values (M11, M12, M21, M22) are subjected to a correlation determination and in the case of a correlation which is too low, the relevant status signal (St11, St12, St21, St22) indicates an invalid measurement value (M11, M12, M21, M22).
4. Method according to one of claims 1 to 3,
   characterised in that
   in method step A, the measuring methods (A11, A12; A21, A22) each have their own time base.
5. Method according to one of claims 1 to 3,
   characterised in that
   in method step A, a time base used in a common manner by at least two measuring methods (A11, A12; A21, A22) is fail-safe.
6. Method according to one of claims 2 to 5,
   characterised in that
   in method step B, at least one evaluation unit (B1, B2) is alternatively configured as a 2 from 2 or a 2 from 3 evaluation system.
7. Method according to one of claims 2 to 6,
   characterised in that
   in method step B, the position and/or speed (M1, M2) is/are determined in the at least one evaluation unit (B1, B2) by means of a statistical method.
8. Method according to one of claims 2 to 7,
   characterised in that
   the evaluation units (B1, B2) and function blocks (A11, A12, A21, A22), in which the measuring methods (A11, A12, A21, A22) are implemented, each have a separate power supply.
9. Method according to claim 8,
   characterised in that
   the evaluation units (B1, B2) and the function blocks (A11, A12, A21, A22) are installed at different sites within a rail vehicle or a railway train.

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