EP0561705A1 - Method and apparatus for vehicle location on a road and its application for analysis and expertise of railroad geometry - Google Patents

Abstract

In order to locate a vehicle on a road, in particular a railroad, there is used: - acquisition means (5), installed on the vehicle (1) capable of travelling on the said road (2), for supplying an acquisition signal of at least one predetermined road configuration parameter, - a reference memory (10) containing reference data representing a pre-established reference road configuration and marking indications associated with at least some of these reference data and corresponding to a marking of the road on the terrain, and - analysis means (6) capable of supplying location data for the vehicle on the road with respect to the terrain based on the acquisition signal and at least part of the contents of the reference memory (10). <IMAGE>

Description

The invention relates to the analysis of data relating to a track, in particular a railway track.

It finds a particularly advantageous application in the analysis and the expertise of the geometry of a railroad track, in particular for the localization of the faults of this track compared to a location marking out the latter and located on the surrounding ground.

The analysis of the geometry of a railway track consists of the acquisition, from displacement or optical sensors placed in a control car traveling on this track, various parameters relating to the latter, such as the superelevation, the 'spacing, the accelerations of the axle box, then in the processing of these parameters including in particular scanning, shaping, and storage operations.

The expertise of the geometry of the railway includes the attachment of the results obtained by the analysis prior to the network frame as well as the establishment of any document necessary for the forecast and control of maintenance operations, such as notes techniques giving the temporal evolution of these results or the exceeding of pre-established thresholds.

In order to be able to dispatch a maintenance team to the site of a detected fault, it is necessary to locate it precisely in relation to a fixed location in the field, such as for example milestones.

The attachment of the records of the various parameters to the network frame, with a view in particular to locating faults, is currently carried out manually based on the measurement of the true distance traveled by the wheels of the vehicle and of the indications reported by the agents present in the car, in particular on the route followed.

However, such a location is subject to inaccuracies from various causes. Among these are the irregularities of the location in the field, such as discontinuous numbering of successive milestones or true distances different from 1000 meters between two consecutive milestones. Uncertainties or errors are also found in the manual indications of the agents. To this can be added unforeseen changes in vehicle lanes during a control operation, compared to a predetermined route, which makes it even more difficult to correspond between the actual kilometers actually traveled by the vehicle wheels and the marking terminals.

The invention aims to provide a more satisfactory solution to these problems.

An object of the invention is, in general, to be able to locate in a relatively safe manner, with respect to a location of the terrain, a vehicle traveling on a lane.

Another object of the invention is to perform such localization either almost in real time or in deferred time.

Another object of the invention is to facilitate the appraisal of the geometry of a railway track, in particular in the location of the faults of this track.

Another object of the invention is to use current materials, which makes it possible to envisage an industrially reasonable cost.

• a) on fait circuler le véhicule sur la voie,
• b) on acquiert, à bord du véhicule, au moins un paramètre prédéterminé de configuration de voie, et
• c) on localise le véhicule sur la voie par rapport au terrain à partir du signal d'acquisition, d'informations de référence représentatives d'une configuration de référence préétablie de la voie et d'indications de repérage associées à certaines au moins de ces informations de référence et correspondant à un repérage sur le terrain.

The invention firstly relates to a method for locating a vehicle on a track such as a railway, in which:

• a) the vehicle is driven on the track,
• b) at least one predetermined lane configuration parameter is acquired on board the vehicle, and
• c) the vehicle is located on the track with respect to the terrain from the acquisition signal, reference information representative of a pre-established reference configuration of the track and location indications associated with at least some of these reference information and corresponding to a location in the field.

The Applicant has in fact observed that it was possible to locate a vehicle on a track by directly detecting the very configuration of this track during the movement of the vehicle, without it being necessary in particular to carry out measurements locating aids from the moving vehicle.

Although different types of predetermined track configuration parameters can be used, it has been found to be particularly advantageous to use the radius of curvature of the track.

• c1) on génère à partir du signal d'acquisition une succession de valeurs de mesure correspondant respectivement à des points d'acquisition espacés sur la voie d'une distance de mesure prédéterminée,
• c2) on convertit ces valeurs de mesure en des indications-types de mesure choisies parmi un jeu préétabli d'indications-types respectivement représentatives de types prédéterminés de configuration de voie relativement audit paramètre prédéterminé, et
• c3) on effectue un traitement de comparaison entre les indications-types de mesure ainsi obtenues et certaines au moins desdites informations de référence comportant des indications-types de référence de même nature que les indications-types de mesure et correspondant également à des points de référence espacés sur la voie d'une distance égale à ladite distance de mesure.

According to an embodiment of the method, in step (c):

• c1) a succession of measurement values is generated from the acquisition signal corresponding respectively to acquisition points spaced apart on the path of a predetermined measurement distance,
• c2) these measurement values are converted into standard measurement indications chosen from a pre-established set of standard indications respectively representative of predetermined types of channel configuration relative to said predetermined parameter, and
• c3) a comparison processing is carried out between the standard measurement indications thus obtained and at least some of said reference information comprising standard reference indications of the same nature as the standard measurement indications and also corresponding to reference points spaced on the track by a distance equal to said measurement distance.

In the case where the radius of curvature of the track is used as a predetermined parameter of track configuration, it is preferable to choose standard measurement indications from a set of three values respectively representative of a curve to the right, of an alignment, that is to say a straight portion of track, and a curve to the left.

In sub-step c1), the acquisition signal is advantageously sampled according to a predetermined sampling step, corresponding to acquisition points spaced apart on the path of an acquisition distance sub-multiple of said measurement distance , and the samples thus obtained are preferably filtered using a weighting eliminating wavelengths lying outside a predetermined range of values.

According to a particular embodiment of the invention, groups or measurement patterns are formed, each comprising a number predetermined successive measurement standard indications, and in sub-step (c3), each measurement group is compared to a plurality of reference groups or patterns, each comprising the same number of reference standard indications as that of the standard measurement indications of the said measurement group concerned.

For the comparison of the measurement group with standard reference indications, a plurality of reference groups is preferably successively established, each reference group overlapping with the previous one by being offset by a step of multiple offset by the measurement step, corresponding to the measurement distance.

• des moyens d'acquisition, embarqués à bord d'un véhicule apte à circuler sur ladite voie, pour délivrer un signal d'acquisition d'au moins un paramètre prédéterminé de configuration de voie,
• une mémoire de référence contenant des informations de référence représentatives une configuration de référence préétablie de la voie, et des indications de repérage associées à certaines au moins de ces informations de référence et correspondant à un repérage de la voie sur le terrain, et
• des moyens d'analyse pour délivrer des informations de localisation du véhicule sur la voie par rapport au terrain à partir du signal d'acquisition et d'une partie au moins du contenu de la mémoire de référence.

The subject of the invention is also a device for processing data relating to a track, such as a railway track, comprising:

• acquisition means, on board a vehicle capable of traveling on said track, to deliver an acquisition signal of at least one predetermined track configuration parameter,
• a reference memory containing reference information representative of a pre-established reference configuration of the track, and location indications associated with at least some of this reference information and corresponding to location of the track in the field, and
• analysis means for delivering information on the location of the vehicle on the track relative to the terrain from the acquisition signal and at least part of the content of the reference memory.

• des moyens de prétraitement comportant
  • . des moyens d'échantillonnage commandés par un signal d'échantillonnage (ou signal de synchronisation), pour échantillonner le signal d'acquisition selon un pas d'échantillonnage prédéterminé, et
  • . des moyens de filtrage numériques du signal échantillonné pour délivrer, selon un pas de mesure multiple du pas d'échantillonnage, des échantillons filtrés, et
• des moyens de traitement comportant
  • . des moyens de conversion aptes à convertir certains au moins des échantillons filtrés obtenus en une suite d'indications-types de mesure choisies parmi un jeu d'indications-types de même nature que les indications-types de référence, à partir de la comparaison de ces échantillons filtrés avec au moins une valeur de seuil prédéterminée,
  • . des moyens de comparaison pour effectuer un traitement de comparaison entre les indications-types de mesure obtenues et certaines au moins des indications-types de référence, et
  • . une mémoire de résultats pour stocker les informations de localisation en correspondance des échantillons filtrés délivrés par les moyens de filtrage numériques.

According to one embodiment of the device according to the invention, in which the reference information comprises reference type indications respectively representative of predetermined types of channel configuration relative to the predetermined parameter, the analysis means comprise:

• pre-treatment means comprising
  • . sampling means controlled by a sampling signal (or synchronization signal), for sampling the acquisition signal according to a predetermined sampling step, and
  • . digital filtering means of the sampled signal to deliver, in a step of multiple measurement of the step sampling, filtered samples, and
• processing means comprising
  • . conversion means able to convert at least some of the filtered samples obtained into a series of standard measurement indications chosen from a set of standard indications of the same nature as the standard reference indications, from the comparison of these samples filtered with at least one predetermined threshold value,
  • . comparison means for carrying out a comparison processing between the standard measurement indications obtained and at least some of the reference standard indications, and
  • . a results memory for storing the location information in correspondence with the filtered samples delivered by the digital filtering means.

The acquisition means advantageously comprise a sensor capable of measuring the true distance traveled by the vehicle on the track and of delivering said sampling signal according to a chosen frequency corresponding to the sampling step. For this purpose, it is possible to provide a sensor for the angle of rotation of a wheel of the vehicle.

• des moyens pour former des groupes de mesure comportant chacun un nombre prédéterminé d'indications-types de mesure successives,
• des moyens de corrélation aptes à effectuer successivement une pluralité de traitements de corrélation entre un groupe de mesure concerné et une pluralité de groupes de références respectifs choisis dans au moins une partie du contenu de la mémoire de référence, comportant chacun un même nombre d'indications-types de référence que celui des indications-types de mesure du groupe de mesure concerné, chaque traitement de corrélation portant sur les indications-type respectives du groupe de mesure et du groupe de référence correspondants, et fournissant une valeur de corrélation, et
• des moyens de test pour tester toutes les valeurs de corrélation obtenues à un critère de corrélation prédéterminé pour asscocier à chaque groupe de mesure un groupe de référence.

The comparison means can include:

• means for forming measurement groups each comprising a predetermined number of successive standard measurement indications,
• correlation means able to carry out successively a plurality of correlation treatments between a measurement group concerned and a plurality of respective reference groups chosen from at least part of the content of the reference memory, each comprising the same number of indications -reference types than that of the standard measurement indications of the measurement group concerned, each correlation processing relating to the respective standard indications of the corresponding measurement group and reference group, and providing a correlation value, and
• test means for testing all the correlation values obtained with a predetermined correlation criterion in order to associate with each measurement group a reference group.

The correlation means preferably comprise logic processing means of the EXCLUSIVE OR type, the correlation criterion then corresponding to the smallest correlation value obtained among those associated with all the chosen reference groups.

• une entrée de synchronisation pour le signal d'échantillonnage (ou signal de synchronisation),
• des moyens d'entrée analogiques pour recevoir le signal d'acquisition,
• des moyens de conversion analogique/numérique reliés aux moyens d'entrée analogiques pour délivrer les échantillons du signal d'acquisition,
• un port synchrone apte à recevoir le signal d'échantillonnage et relié aux moyens d'entrée analogiques par un bus de commande,
• un processeur de traitement de signal incorporant les moyens de filtrage numériques, relié à une mémoire de travail, à une mémoire de programme, au port synchrone et aux moyens de conversion analogique/numérique par un bus de communication, cadencé par un signal d'horloge tiré du signal d'échantillonnage, et apte à commander les moyens analogiques d'entrée par le bus de commande, et
• une interface de sortie pour délivrer les échantillons filtrés.

According to one embodiment of the invention, the pretreatment means comprise:

• a synchronization input for the sampling signal (or synchronization signal),
• analog input means for receiving the acquisition signal,
• analog / digital conversion means connected to the analog input means for delivering the samples of the acquisition signal,
• a synchronous port capable of receiving the sampling signal and connected to the analog input means by a control bus,
• a signal processing processor incorporating the digital filtering means, connected to a working memory, to a program memory, to the synchronous port and to the analog / digital conversion means by a communication bus, clocked by a clock signal taken from the sampling signal, and able to control the analog input means by the control bus, and
• an output interface for delivering the filtered samples.

While the preprocessing means can be incorporated within one or more electronic cards, the processing means are advantageously incorporated within a microcomputer comprising an input interface capable of cooperating with the output interface of the means pretreatment by a specific bond.

According to an embodiment of the invention, more particularly intended for the analysis and the expertise of the geometry of a track, such as a railway track, the acquisition means are able to acquire almost simultaneously said signal d acquisition of the predetermined configuration parameter, such as the radius of curvature of the channel, of the auxiliary acquisition signals representative of other parameters relating to the quality of the channel, and the analysis means are capable of determining the evolution of all the parameters measured and to establish a spatial correspondence between these evolutions and the location in the field using the location information obtained.

In this case, the analog input means may comprise a multiplexer, the inputs of which are connected to the various sensors of the acquisition means, the output of which is connected to the analog / digital conversion means, this multiplexer being controlled by the bus. control from the sampling signal acting as synchronization signal, the digital filtering means acting on the samples of all the acquisition signals.

In particular in order to improve the speed of locating the vehicle on the track, the device may include an auxiliary location system, for example by satellite, capable of performing a pre-location of the vehicle on the track, which then makes it possible not to use for example, only part of the content of the reference memory for tracking the location of the vehicle.

• la figure 1 est un synoptique schématique d'un dispositif selon l'invention incorporé au sein d'un véhicule circulant sur une voie;
• la figure 2 illustre plus en détail le dispositif de la figure 1;
• la figure 3 représente un organigramme de fonctionnement d'un dispositif selon l'invention;
• la figure 4 illustre des échantillons et des indications-types de mesure obtenus; et
• les figures 5 et 6 illustrent plus en détail des parties de l'organigramme de la figure 3.

Other advantages and characteristics of the invention will appear on examining the detailed description below illustrating a particular non-limiting embodiment of the invention, and the appended drawings in which:

• Figure 1 is a schematic diagram of a device according to the invention incorporated within a vehicle traveling on a track;
• Figure 2 illustrates in more detail the device of Figure 1;
• FIG. 3 represents an operating flow diagram of a device according to the invention;
• FIG. 4 illustrates samples and standard indications of measurement obtained; and
• FIGS. 5 and 6 illustrate in more detail parts of the flow diagram of FIG. 3.

In FIG. 1, the reference 1 designates a vehicle such as a control car able to run on a railroad track 2 in order to analyze the geometry of the latter for expert purposes.

On board this vehicle 1 are onboard acquisition means 5 for delivering at least one acquisition signal of at least one preset channel configuration parameter, such as the radius of curvature. As will be explained in more detail below, these acquisition means are also capable of measuring the angle of rotation of a wheel 4 of the vehicle.

These acquisition means 5 are connected to analysis means 6 capable of delivering the location information of the vehicle on the track 2 relative to the terrain from the acquisition signal of the predetermined track configuration parameter, delivered by the means of acquisition, and of at least part of the content of a reference memory 10. The latter contains reference information representative of a preset reference configuration of the channel, and location indications associated with some of the less of this reference information and corresponding to a location of the track in the field using kilometer markers 3 for example.

In general, the analysis means 6 comprise preprocessing means 7 incorporated within one or more electronic cards connected to a microcomputer 8, for example of the PC (registered trademark) type, which incorporates means of treatment.

When the operating conditions allow it, an auxiliary location device 9 can also be used, for example by satellite such as the so-called GPS system (Global positioning system). Such an auxiliary system then makes it possible to pre-locate the vehicle on the track while ensuring an approximate absolute location. The tracking of the vehicle on the own reference system of the track 2 is then ensured by the pre-treatment and treatment means.

Although the microcomputer 8 is shown in this figure on board the vehicle, which is necessary during a real-time location processing, it is conceivable that the data delivered by the preprocessing means 7 are stored in a memory of transition which can be read later in deferred time by the microcomputer installed in a laboratory on shore. Of course, it is possible in the latter case to still use the microcomputer on board the vehicle but only for its function of receiving data from the preprocessing means 7 for storage in an appropriate diskette.

In the application for analysis and expertise of the geometry of the railroad track 2, the acquisition means 5 comprise (FIG. 2) a plurality of displacement or optical sensors 11, 12, 13 capable of acquiring signals representative analog acquisition of various parameters relating to the quality of the railway.

Among these sensors, use will preferably be made of a sensor for measuring the angle of rotation a of a wheel 4 of the vehicle in order to measure the true distance traveled by this wheel and to deliver a sampling signal according to a chosen frequency corresponding to a predetermined acquisition distance (no sampling) separating two successive acquisition points. In the example described, this acquisition distance is of the order of 50 cm.

The measurement of the radius of curvature of the track at the various acquisition points is determined from a sensor 12 for measuring the deflection f of a track arc. It would also be possible to determine this radius of curvature from a sensor measuring the rotation occurring between the bogie and the body of the vehicle when it travels a curve. The sensor 13 can for example be an acceleration sensor of the axle box or any other sensor suitable for the analysis of the geometry of a track.

The signal from the sensor 11 is delivered to a synchronization input 15 of an electronic card 14 while the outputs of the other sensors 12, 13 are connected by a connector, not shown, to inputs 17 of this card 14.

A non-linear amplifier 16 is connected to the synchronization input 15 to receive the sampling signal and to format it so as to deliver it to a synchronous port 25 of another electronic card 21. It will be seen below that the signal delivered to this synchronous port in fact acts as a synchronization signal making it possible to deduce a clock signal timing the digital processing carried out on this card 21.

The inputs 17 of the card 14 are respectively connected to the inputs of an analog multiplexer 19 via analog anti-aliasing filters 18. The output of this analog multiplexer 19 is connected to an input port 26 comprising analog / digital conversion means. This port 26 can also be used as an output in connection with digital / analog conversion means to deliver an analog control signal 66 of the filtered signal delivered by the preprocessing means.

The multiplexer 19 is controlled by a control bus 29 coming from the synchronous port 25.

The electronic card 21 is structured around a signal processing processor such as that sold by the United States company MOTOROLA under the reference DSP 56 001. This processor 22 is conventionally associated with a fast working memory 23 and to a program read-only memory 24, advantageously reprogrammable for example of the "EPROM" or "EEPROM" type.

Finally, an output interface 27 is provided for a serial link 35 of the RS 232 type to the processing means 8.

The various components of this card 21 are linked together by a communication bus 28. The power supply to the cards 14 and 21 is provided by a power supply unit 20.

Without going into the details of the operation of the device of the invention here, which will be explained below, it can already be said that the processor 22 and its associated program software control the multiplexer 19 via the synchronous port 25 and the control bus 29, so that an analog value 26 is delivered by analog / digital conversion means to obtain a digital sample at the output of these means. Also, the processor 22 and its program software, the synchronous port 25, the control bus 29, the multiplexer 19 and the analog / digital conversion means form means for sampling the acquisition signal picked up by the sensor 12. Of course, these same means also contribute to sampling the other measurement signals from the other sensors 13. Those skilled in the art will therefore notice here that almost all the parameters are acquired (when switching the inputs of the multiplexer 19) used for channel analysis. This quasi synchronization is obtained from the sampling signal delivered to the synchronization input and acting here as a synchronization signal.

The processor 22 also incorporates a software module implementing digital filtering means of the sampled signal delivered at the output of the analog / digital conversion means 26.

The processor 22 makes it possible to extract from the sampled signals, the mean value of the signal and the difference between the sampled signal and its mean value. This information then makes it possible to calculate standard deviations over a predetermined fixed length, here of the order of 50 m.

The digital filtering means here use filtering of the non-recursive type with finite impulse response. Thus, if y _i denotes a sample before filtering, and if z _i denotes the corresponding filtered sample, this sample z _i is obtained by the relation given by formula (I):

In this formula, the coefficients h _j are the weighting coefficients of the digital filter. These coefficients h _j are in theory part of an infinite sequence which is in practice truncated to a finite number of coefficients; one can thus for example take n equal to 50. They are advantageously obtained from a cardinal filter eliminating the wavelengths lying outside a predetermined range [l₁, l₂]. The choice of this value range depends of course on the wavelengths that one wishes to analyze in the difference between the sampled signal and its average value, taking into account the choice of the preset configuration parameter.

In the application envisaged here, the wavelength in fact represents the length of a track curve.

This average length is at least of the order of a hundred meters while the curvature defects of this channel have wavelengths less than about 40 meters. In other words, it extends over a track length generally not exceeding 40 meters. Also, we will eliminate in practice all wavelengths less than forty meters. The value range considered here therefore contains all values greater than approximately 40 meters. The location of the vehicle from the measurement of the radius of curvature will thus not be disturbed by information representative of the actual curvature defects of the track.

dans laquelle δ₁ désigne le pas d'échantillonnage correspondant à la distance d'acquisition minimale de 50 cm. Compte tenu de la plage de valeur choisie, l₂ est pris égal à 40 tandis que 1/l₁ est pris égal à 0.The weighting coefficients h _j are then preferably calculated, for a rectangular cardinal filter which eliminates all wavelengths outside the chosen range, by the formula (II):

in which δ₁ denotes the sampling step corresponding to the minimum acquisition distance of 50 cm. Taking into account the chosen value range, l₂ is taken equal to 40 while 1 / l₁ is taken equal to 0.

It is thus possible to detect any track curve with a length ranging from 40 meters to ten kilometers.

Of course, it is possible to use numerous variants of filters of the same type, in particular with the aim of softening the rising and falling edges in the changes of the parameters, with a view to limiting the phenomena of "rebound", well known from the skilled person.

The processor 22 then samples the filtered signal in order to deliver at the output of the output interface 27 a sample filtered according to a measurement step which is generally a multiple of the sampling step. In this case, a series of samples will be delivered corresponding to points on the track spaced by a measurement distance equal to 12.50 meters.

The microcomputer 8 conventionally comprises a central unit 31 associated with a working working memory 32, read-only memory 33 as well as with an input interface 34 capable of receiving the filtered samples delivered by the output interface 27.

Thus, as will be seen in more detail below, the central unit 31 incorporates software means 36 for conversion capable of convert at least some of the filtered samples obtained into a series of standard measurement indications, and comparison means 37 to carry out a comparison processing between the standard measurement indications thus obtained and at least some standard indications of reference contained in the reference memory 10.

Functionally, these comparison means 37 are subdivided into means 38 to form measurement groups each comprising a predetermined number of successive measurement standard indications, into correlation means 39 based on logic OR EXCLUSIVE processing and into means test 40 of all the correlation values obtained from the correlation means 39.

In the case in particular where the location processing is carried out in real time, that is to say on board the vehicle itself, there is provided a result memory 30 such as a floppy disk, for storing the location information. obtained in correspondence with the filtered samples delivered by said preprocessing means.

Reference is now made to FIGS. 3 to 6 to describe in detail the operation of the data processing device according to the invention, and first of all the method of locating the vehicle itself on the track.

As described above, the output interface 27 of the preprocessing means 7 delivers EFi filtered samples such as those referenced 46, 47, 48, 49 on the upper part of FIG. 4.

These EFi samples were obtained after an acquisition step 42 of the sampling signal (synchronization) and of the acquisition signal relating to the predetermined channel configuration parameter (here the radius of curvature), followed by a first sampling 43 providing at the output of the analog / digital conversion means 26 the sampled acquisition signal, then of a digital filtering 44 by the processor 22 and finally of a sampling 45 of the final signal obtained in order to deliver the EFi samples.

As can be seen in the upper part of Figure 4, the EFi filtered samples are distributed on either side of two predetermined threshold values S1 and S2 according to the configuration of the channel.

In the example considered here, the values S1 and S2 are opposite and their absolute value is taken equal to 5000 meters but is advantageously configurable.

The value of each EFi sample is proportional to the curvature of the track (inverse of the radius of curvature), and two successive samples correspond to acquisition points spaced on the track by the measurement distance D here equal to 12.50 meters .

The conversion step 50 of these filtered samples into standard measurement indications IMi consists in comparing each sample EFi with the two threshold values S1 and S2 in order to assign it a value chosen from a pre-established set of predetermined values representative of different types of channel configuration.

In this case, we differentiate here curves to the left of the track, curves to the right, and alignments, that is to say straight parts.

Thus, each time a filtered sample corresponds to a straight part of the channel, it is assigned the value 0, while to a representative sample of a curve on the left is assigned the value -1 and to a representative sample a curve on the right is assigned the value -1.

FIG. 5 schematically represents the conversion algorithm. If the value of an EFi sample is greater than the threshold value S1 (step 58), the corresponding standard measurement indication 52 is equal to 1. If the EFi sample lies within the interval defined by the two values of threshold S1 and S2 (step 59) the standard indication of measurement referenced 51 or 53, is equal to 0 while in all other cases this standard indication of measurement is equal to -1 (reference 54).

Thus, at the end of this conversion processing 50, the series of filtered samples 46, 47, 48, 49 is converted into a series of standard measurement indications 51, 52, 53, 54 assigned values 0 or 1 or -1 , and coded on two bits.

The reference memory 10 contains standard reference indications of the same nature as the standard measurement indications. In in other words, the content of the reference memory consists of a series of values 0.1 or -1 corresponding to points on the track also spaced apart by a distance of 12.50 meters.

In general, step 55 (FIG. 3) consists of a comparison processing between the content of the reference memory 10 and all of the standard measurement indications IMi, in order to deliver location information in a step 56.

According to a particular implementation of the invention, as illustrated in FIG. 6, the comparison step 55 comprises first of all a grouping of the standard measurement indications into groups or measurement patterns MT, each comprising a predetermined number of successive standard measurement indications and therefore corresponding to sections of predetermined length on the track, for example here of the order of 10 kilometers.

A measured pattern (or measurement group) 70 (FIGS. 3, 4) is then compared with a reference pattern MRj extracted from the reference memory 10 and comprising the same number of standard indications as this measured pattern.

Given the 2-bit coding of each standard indication, a reference pattern corresponding to a 10 km section of track represents 200 bytes of memory.

In step 60, the correlation means are suitable for performing a correlation processing relating to the standard indications for measurement of the measured pattern concerned MT (here the pattern 70) and of the reference pattern MRj. This correlation processing consists in performing an operation of the EXCLUSIVE OR type on the standard indications of these two patterns in order to provide a correlation value Vj referenced 61.

More precisely, the correlation processing consists in successively comparing two by two a standard measurement indication of the measured pattern and a standard reference indication of the reference pattern and then summing all the results obtained in order to obtain the value of correlation Vj. It is recalled here that according to the logic table of an EXCLUSIVE OR gate, the output signal of such a gate is at the value 0 when the two inputs are identical while it takes the value 1 when the two inputs are different.

Also, two identical patterns compared will give a theoretical correlation value equal to 0.

When this first correlation processing is carried out with the reference pattern MRj, the measured pattern MT is compared with another reference pattern MRj + 1 which is advantageously offset from the previous reference pattern by a step of multiple shift of the measurement step. In other words, each reference pattern overlaps with the previous one by being offset by a measurement point, that is to say by a distance of 12.50 meters on the track. Of course, it would have been possible to shift each reference pattern from the previous one by a greater distance, multiple of the distance of 12.50 meters.

This new correlation processing provides a correlation value Vj + 1.

As long as the index j has not reached a value n (step 62), the correlation treatments continue with other reference patterns. We can thus explore the entire content of the reference memory or only a part if, for example, we know approximately where the vehicle is located in relation to the terrain.

At the end of these correlations, the test means compare all of the correlation values obtained Vj (j = 1 to n), in step 64, with a correlation criterion which is here, taking into account the logical processing OR EXCLUSIVE chosen, the selection of the smallest correlation value obtained.

If Vk designates this smallest correlation value obtained, the reference pattern corresponding to the 10 km area in which the vehicle was located during the acquisition of the relevant measured pattern MT, is the reference pattern MRk (reference 65).

Also, given that this reference pattern MR _k is associated with at least one indication of location on the ground, it is thus possible to assign to this measurement pattern concerned information on the location of the vehicle on the track (step 56 ).

In the particular application of the analysis and expertise of the geometry of the railway, it has been seen in FIG. 2 in particular that the acquisition means 5 are able to acquire almost simultaneously with said audit acquisition signal of the predetermined channel configuration parameter (radius of curvature), auxiliary acquisition signals of other parameters representative of the quality of the channel, in particular by the sensors 13. This almost simultaneous acquisition is done by the through the switching of the inputs of the multiplexer 19 by the control bus 19.

Also, the analysis means are capable of subsequently determining the evolution of all the parameters measured, in particular by graphs and can establish a spatial correspondence between these evolutions and the location in the field using location information. determined from the different values obtained by measuring the radius of curvature of the track.

Of course, the invention is not limited to this single choice of the radius of curvature of the track as a determined track configuration parameter for locating the vehicle. One can thus for example use to configure the configuration of the channel, the locations of the fixed contacts of the latter generally arranged in the vicinity of the light signals, and which operate by reverse polarity between the fixed contact and the channel depending on whether the light signal correspondent is open or closed.

It has also proved advantageous to couple such a location device with the auxiliary location device 9, which makes it possible to pre-locate the vehicle on the track and therefore only use, for example, only a portion. of the content of the reference memory 10 for tracking the vehicle on the track's own reference frame.

The invention therefore makes it possible to locate a vehicle on a track from the correlation between a measured quantity physically attached to the track and the same quantity recorded in a memory or reference file.

This reference file may be preexisting and may have been established manually from the track layouts. It can also be formed by learning during successive control tours by an appropriate learning process.

From the acquisitions of the various parameters in real time at on board the vehicle which can currently reach speeds of 180 km / h, it is possible to attach the records of these parameters to the frame of the rail network and track consistencies (armament, engineering structures, etc.) taking into account the singularities mileage, region or district limits, with a view to compiling technical notes on well-defined track lengths making it possible to precisely locate the detected faults.

It would also be possible to have on board the vehicle only the acquisition means associated with a memory for storing the values of the acquired parameters and of the synchronization signal, and to carry out the pretreatment (digital filtering) and subsequent processing on land. (conversion, localization) of the acquired data. With this in mind, the hardware and software structures of the preprocessing means in particular, allow preprocessing from the data stored on the memory and re-delivered at an accelerated speed, for example in a ratio of 16 relative to the acquisition speed.

Claims (20)

Method for locating a vehicle on a track, in particular a railroad track, characterized by the following steps: a) driving the vehicle (1) on the track (2), b) at least one predetermined lane configuration parameter is acquired (42) on board the vehicle, and c) the vehicle is located (56) on the track with respect to the terrain from the acquisition signal, reference information representative of a pre-established reference configuration of the track and associated location indications (3) at least some of this reference information and corresponding to a location in the field. Method according to claim 1, characterized in that in step (c): c1) a succession of measured value values is generated from the acquisition signal corresponding respectively to acquisition points spaced apart on the path of a predetermined measurement distance (D), c2) these measurement values are converted (50) into standard measurement indications, chosen from a preset set of standard indications respectively representative of predetermined types of channel configuration relative to said predetermined parameter, and c3) a comparison processing (55) is carried out between the standard measurement indications thus obtained and at least some of the reference information comprising standard reference indications of the same nature as the standard measurement indications and also corresponding to points reference points spaced on the track by a distance equal to said measurement distance. Method according to claim 2, characterized in that in sub-step c1) the acquisition signal is sampled (43) according to a predetermined sampling step corresponding to acquisition points spaced apart on the path of a distance sub-multiple acquisition of the measurement distance, and the samples thus obtained are filtered (44) using a weighting eliminating wavelengths outside a predetermined range of values. Method according to claim 2 or 3, characterized in that measurement groups are formed each comprising a predetermined number of successive standard measurement indications, and in that in sub-step c3) each group is compared of measurement to a plurality of reference groups each comprising the same number of reference standard indications as that of the standard measurement indications of said measurement group. Method according to Claim 4, characterized in that a plurality of reference groups is successively established, each reference group overlapping with the previous one by being offset by a step of multiple offset from the measurement step, corresponding to the distance of measurement .. Method according to one of the preceding claims, characterized in that the radius of curvature of the track is used as a predetermined parameter of track configuration. Method according to claim 2 and 6 taken in combination, characterized in that one chooses the standard indications of measurement are chosen from a set of three values respectively representative of a curve on the right, of an alignment, and d 'a curve on the left. Application of the method according to one of claims 1 to 7, to the analysis and expertise of the geometry of a railroad track, in particular to the location of faults in this track. Device for processing data relating to a track, in particular a railway track, characterized in that it comprises: acquisition means (5), on board a vehicle (1) capable of traveling on said track (2), to deliver an acquisition signal of at least one predetermined track configuration parameter, - a reference memory (10) containing reference information representative of a preset reference configuration of the channel, and location indications associated with at least some of this reference information and corresponding to track location in the field, and - analysis means (6) capable of delivering information on the location of the vehicle on the track with respect to the terrain from the acquisition signal and at least part of the content of the reference memory (10). Device according to claim 9, characterized in that the reference information includes reference type indications respectively representative of predetermined types of channel configuration relative to the predetermined parameter,
by the fact that the analysis means (6) include: - pre-treatment means (7) comprising . sampling means controlled by a sampling signal to sample the acquisition signal according to a predetermined sampling step, . digital filtering means (22) of the sampled signal to deliver, according to a measurement step multiple of the sampling step, filtered samples, and - processing means (8) comprising . conversion means (36) capable of converting at least some of the filtered samples obtained into a series of standard measurement indications chosen from a set of standard indications of the same nature as the standard reference indications, from comparison of these filtered samples with at least one predetermined threshold value (S1, S2), . comparison means (37) for performing a comparison processing between the standard measurement indications obtained and at least some of the reference standard indications, and . a results memory (30) for storing the location information in correspondence with the filtered samples delivered by the digital filtering means. Device according to claim 10, characterized in that the acquisition means comprise a sensor (11) capable of measuring the true distance traveled by the vehicle on the track, in particular a sensor of the angle of rotation of a wheel of the vehicle, and to deliver said sampling signal at a chosen frequency corresponding to the sampling step. Device according to claim 10 or 11, characterized in that the comparison means comprise: - means (38) for forming measurement groups each comprising a predetermined number of successive measurement type indications, - correlation means (39) able to carry out successively a plurality of correlation treatments between a measurement group concerned and a plurality of respective reference groups chosen from at least part of the content of the reference memory, each comprising the same number of reference standard indications than that of the standard measurement indications of the measurement group concerned, each correlation processing relating to the respective standard indications of the measurement group and of the corresponding reference group, and providing a correlation value (Vj),
· Test means (40) for testing all the correlation values obtained with a predetermined correlation criterion to associate, with each measurement group, a reference group. Device according to claim 12, characterized in that the correlation means (39) comprise logic processing means of the EXCLUSIVE OR type, the correlation criterion corresponding to the smallest correlation value obtained among those associated with all the groups of reference chosen. Device according to one of claims 10 to 13, characterized in that the pretreatment means (7) comprise: - a synchronization input (15) for the sampling signal, - analog input means (18, 19) for receiving the acquisition signal, - analog / digital conversion means (26) connected to the analog input means for delivering samples of the acquisition signal, a synchronous port (25) capable of receiving the sampling signal, and connected to the analog input means by a control bus (29), - a signal processing processor (22) incorporating the digital filtering means, connected to a working memory (23), to a program memory (24), to the synchronous port (25) and to the analog-to-digital conversion means ( 26) by a communication bus (28), clocked by a clock signal drawn from the sampling signal and capable of controlling the analog input means (19) by the control bus (29), and - an output interface (27) for delivering the filtered samples. Device according to Claim 14, characterized in that the signal processing processor is capable of performing filtering of the non-recursive type with finite impulse response, with weighting coefficients chosen to eliminate wavelengths outside of 'a range of predetermined values. Device according to one of claims 10 to 15, characterized in that the processing means (8) are incorporated within a microcomputer comprising an input interface (34) capable of cooperating with the output interface ( 27) means for pretreatment by a specific link (35). Device according to one of Claims 9 to 16, characterized in that the predetermined channel configuration parameter is the radius of curvature of this channel, and in that the reference standard indications are chosen from a set of three values respectively representative of a curve on the left, of an alignment and of a curve on the right of the track, and correspond respectively to points of the track spaced by a measurement distance corresponding to the measurement step. Device according to one of claims 9 to 17, characterized in that the acquisition means are able to acquire, almost simultaneously with said acquisition signal of the predetermined channel configuration parameter, auxiliary acquisition signals representative of other parameters relating to the quality of the channel,
and by the fact that the analysis means are capable of determining the evolution of all the parameters measured and of establishing a spatial correspondence between these evolutions and the location in the field using the location information obtained. Device according to claim 18, characterized in that the analog input means comprise a multiplexer (19), the inputs of which are connected to the various sensors of the acquisition means, the output of which is connected to the analog / digital conversion means, controlled by the control bus from the sampling signal acting as synchronization signal, the digital filtering means acting on the samples of all the acquisition signals. Device according to one of claims 9 to 19, characterized in that it comprises an auxiliary location system (9), for example by satellite, capable of performing a pre-location of the vehicle on the track.

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