US20230227083A1 - Method for locating and/or measuring the speed of a vehicle - Google Patents
Method for locating and/or measuring the speed of a vehicle Download PDFInfo
- Publication number
- US20230227083A1 US20230227083A1 US18/155,280 US202318155280A US2023227083A1 US 20230227083 A1 US20230227083 A1 US 20230227083A1 US 202318155280 A US202318155280 A US 202318155280A US 2023227083 A1 US2023227083 A1 US 2023227083A1
- Authority
- US
- United States
- Prior art keywords
- markers
- guideway
- sensor
- vehicle
- marker
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims description 25
- 239000003550 marker Substances 0.000 claims abstract description 41
- 238000001514 detection method Methods 0.000 claims abstract description 11
- 239000002184 metal Substances 0.000 claims description 13
- 230000006870 function Effects 0.000 claims description 7
- 238000012545 processing Methods 0.000 claims description 5
- 230000000704 physical effect Effects 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 4
- 230000006698 induction Effects 0.000 claims description 3
- 230000000737 periodic effect Effects 0.000 claims description 3
- 230000011664 signaling Effects 0.000 claims description 3
- 238000012795 verification Methods 0.000 claims description 3
- 230000002596 correlated effect Effects 0.000 claims 1
- 230000000875 corresponding effect Effects 0.000 claims 1
- 238000005259 measurement Methods 0.000 description 16
- 230000001939 inductive effect Effects 0.000 description 14
- 239000011295 pitch Substances 0.000 description 12
- 230000003137 locomotive effect Effects 0.000 description 4
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000000739 chaotic effect Effects 0.000 description 2
- 238000002513 implantation Methods 0.000 description 2
- 206010001488 Aggression Diseases 0.000 description 1
- 239000010750 BS 2869 Class C2 Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000016571 aggressive behavior Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000002775 capsule Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- PLAIAIKZKCZEQF-UHFFFAOYSA-N methyl 6-chloro-2-oxo-3h-1,2$l^{4},3-benzodithiazole-4-carboxylate Chemical compound COC(=O)C1=CC(Cl)=CC2=C1NS(=O)S2 PLAIAIKZKCZEQF-UHFFFAOYSA-N 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 230000011218 segmentation Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L25/00—Recording or indicating positions or identities of vehicles or trains or setting of track apparatus
- B61L25/02—Indicating or recording positions or identities of vehicles or trains
- B61L25/025—Absolute localisation, e.g. providing geodetic coordinates
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L25/00—Recording or indicating positions or identities of vehicles or trains or setting of track apparatus
- B61L25/02—Indicating or recording positions or identities of vehicles or trains
- B61L25/021—Measuring and recording of train speed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L25/00—Recording or indicating positions or identities of vehicles or trains or setting of track apparatus
- B61L25/02—Indicating or recording positions or identities of vehicles or trains
- B61L25/026—Relative localisation, e.g. using odometer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L3/00—Devices along the route for controlling devices on the vehicle or train, e.g. to release brake or to operate a warning signal
- B61L3/02—Devices along the route for controlling devices on the vehicle or train, e.g. to release brake or to operate a warning signal at selected places along the route, e.g. intermittent control simultaneous mechanical and electrical control
- B61L3/08—Devices along the route for controlling devices on the vehicle or train, e.g. to release brake or to operate a warning signal at selected places along the route, e.g. intermittent control simultaneous mechanical and electrical control controlling electrically
- B61L3/12—Devices along the route for controlling devices on the vehicle or train, e.g. to release brake or to operate a warning signal at selected places along the route, e.g. intermittent control simultaneous mechanical and electrical control controlling electrically using magnetic or electrostatic induction; using radio waves
- B61L3/121—Devices along the route for controlling devices on the vehicle or train, e.g. to release brake or to operate a warning signal at selected places along the route, e.g. intermittent control simultaneous mechanical and electrical control controlling electrically using magnetic or electrostatic induction; using radio waves using magnetic induction
Definitions
- the present disclosure relates to a method for locating and/or measuring the speed of a vehicle moving along a guideway, for example, a railway track formed by two rails, and to a device equipping such a vehicle, in particular, an autonomous shuttle.
- a vehicle moving along a guideway for example, a railway track formed by two rails
- a device equipping such a vehicle in particular, an autonomous shuttle.
- Satellite geolocation systems consisting in calculating the current position on the earth's surface, using signals emitted by a constellation of satellites provided for this purpose, are not suitable for vehicles that, for security reasons, require precise and robust positioning with continuous availability.
- the accuracy of GPS systems remains dependent on meteorological conditions and disruptive geographical elements (proximity to dense vegetation, for example).
- Availability is not guaranteed when the vehicle crosses an area without radio frequency coverage, for example, a tunnel or underground, deep valleys or urban corridors.
- these systems may be subject to malicious acts of jamming, or interruption of service.
- ERTMS European Rail Traffic Management System
- a mobile device is therefore usually positioned on a rail, in particular, according to the CBTC [IEEE 1474] and ERTMS [Annex A of the CCS TSI—SUBSET 026 ] recommendations by two redundant techniques:
- balises are placed on the track between the rails. Without supervision, they are thus vulnerable to acts of vandalism. They are also subjected to relatively high mechanical stresses when a train passes, which can cause failures. Apart from the cost generated by the maintenance of these balises, there is also a cost linked to the installation of these balises on the entire rail network and to stock management. In addition, this solution poses a security problem, since if a balise were to no longer operate, the interval between two readjustments of position measurements from the odometry sensors would be increased.
- Some solutions seek to make the odometry system more robust by no longer relying on a wheel rotation measurement. They propose using the track as a regularly spaced magnetic strip by equipping the mobile on rail with a magnetic sensor. Reading the magnetic strip makes it possible to measure the movement speed and the position variation with greater precision than odometry systems based on the wheel speed [DE2164312]. Such a solution, however, requires having a magnetic marker on the entire network while respecting the very strong positioning constraints of these markers in order to guarantee the regularity of the spacing.
- Solutions based on inductive reading of markers are interesting because they are generally insensitive to atmospheric conditions, unlike solutions based on optical reading or on radio frequency data exchange, which are robust because inductive reading is done by an electromagnetic coil that does not require any maintenance and that withstands vibrations, impacts and physical aggressions of all kinds with no problems, and uses inexpensive solutions to exploit the signals.
- US patent U.S. Pat. No. 8,067,933B2 relating to a device for locating a vehicle associated with a track, comprising reference marks, which are placed on the track, and detection means arranged in the vehicle, which produce at least one output signal when passing a reference mark.
- the detection means are composed of several individual sensors that extend in the direction of travel with an average detection length greater than or equal to the distance between neighboring reference marks.
- Also known from patent EP2065288 is a railroad positioning system provided with an on-board speed measuring device inducing eddy currents in the track structure, at two places along the direction of travel, measuring the variations in the magnetic field emitted by the track structure and determining position and speed by correlating the two measured signals and a coded track tag providing coding recognizable by the on-board speed measuring device.
- An embodiment proposed by this document concerns the use of coded tags consisting of a bar with several slots in which metal blocks of different sizes are mounted. Block sizes and positions are selected to represent Quadrature Amplitude Modulation coding.
- Patent FR3055876 relates to a method for determining the position of a railway vehicle traveling on a railway track provided with a plurality of structural elements each comprising a device for storing identification data, comprises a prior step of obtaining a data sequence so as to form a list of data sequences each successively identifying a successive structural element. This method also comprises steps of initialization, during which a data sequence is retrieved; reading the identification data item associated with the structural element over which the vehicle passes; modifying the data sequence as a function of the identification datum; and calculating the position of the vehicle according to the data sequence.
- Application WO01/66401 relates to a device for determining the position of a rail vehicle.
- This device comprises at least one sensor suitable for generating a signal depending on the irregularities of the railway track caused by the rail components mounted on the railway track or connected thereto; a memory means suitable for storing, on the one hand, information relating to the position of the components of the rail along the path of the vehicle and, on the other hand, characteristics necessary for identifying the components of the rail; an identification means suitable for detecting and identifying the components of the rail by comparing the signal with the stored characteristics; a calculating means designed to determine the position of the vehicle from the identified rail components and their stored position.
- the invention thereof also relates to a method for determining the position of a rail vehicle.
- the position and the characteristics of the components of the rail mounted on the railway track or connected thereto are previously recorded and stored.
- a signal is produced based on the irregularities caused by these components.
- the signal is compared to the characteristics, whereby the rail components are detected and identified, and the position of the vehicle is determined from the identified rail components and their stored position.
- Patent application DE102019118767 relates to a method for detecting the position of a railway vehicle on a railway track, as well as a railway track designed to implement such a method.
- the position of the railway vehicles is detected by way of a sensor of the vehicle that detects, during its passage on the railway track, a sequence of magnetic fields generated by magnets arranged on the railway track and generates, from the variations of the resulting magnetic field, a binary model whose data content represents a local coordinate of the railway track.
- the equipment of a set of guideways can constitute a considerable investment, and mobilization of multiple resources may be required to configure the markers installed on the network, which constitute a database whose maintenance and updating represent considerable work in themselves.
- the present disclosure relates to a system for the geolocation of vehicles traveling on a guideway comprising:
- the term “randomly” means that the choice of the property of each of the markers distributed on the track is established without an identifiable prediction rule, for example, by the result of chance or of a chaotic sequence generator.
- the physical characteristic is magnetic induction.
- the markers are conductive masses and the sensors comprise a transmitter coil powered by an alternating electric current and by a receiver coil detecting the magnetic field induced by a conductive marker to produce an electric current processed to provide a signal when in proximity to a conductive marker.
- the markers are magnetic masses and the sensors are constituted by a receiver coil detecting the magnetic field induced by a magnetic marker to produce an electric current processed to provide a signal when in proximity to a magnetic marker.
- the physical property is the length in the direction of the trajectory of the vehicle on the guideway, and the membership classes correspond to ranges of length with no overlap between the ranges.
- the physical property is the length in the direction of the trajectory of the vehicle on the guideway, and the membership classes correspond to ranges of length with no overlap between the ranges.
- the markers are positioned between the rails forming the guideway.
- the database also comprises the recordings of the distances separating two consecutive markers.
- the distribution of the markers on the guideway is periodic.
- the vehicles further comprise a second geolocation means, the computer applying a consistency verification process between the geolocation information supplied by the sensor and the information supplied by the second geolocation means.
- the present disclosure also relates to a method for geolocating vehicles equipped with a sensor for detecting a physical characteristic of markers, traveling on a guideway comprising a distribution of markers having a physical characteristic detectable by the sensors, characterized in that the method comprises recording, during the movement, a sliding window of the property of each of the markers detected by the sensor of the vehicle, and in comparing the sequence recorded during the movement of the vehicle with the sequences recorded in a database containing an ordered recording of the class to which each of the markers arranged on the guideway belongs in a database, each of the recordings being associated with location information relative to the physical position of the marker on the guideway.
- FIG. 1 shows a schematic view of a section of guideway according to the present disclosure
- FIG. 2 shows a view of the sequences of signals processed by the computer
- FIG. 3 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a first position
- FIG. 4 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a second position
- FIG. 5 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a third position
- FIG. 6 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a fourth position
- FIG. 7 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a fifth position
- FIG. 8 shows a schematic view of the digital processing operations.
- the positioning system will be described below according to a non-limiting example where the markers are metallic masses, the physical property taken into account is the length along the trajectory of the vehicle ( 1 ), and the sensors are inductive sensors and autonomous shuttle vehicles traveling on a dedicated track with guide rails.
- the vehicles are also equipped, according to a preferred option, with a second location system, for example, an odometer taking into account the rotation of one of the wheels of the vehicle, or possibly radio transmitter balises arranged along the guideway, or even a GPS system, the data of which in the uncovered area will be extrapolated from data provided by, for example, an inertial unit.
- the guideway can form a single closed loop, or on the contrary have multiple branches.
- the vehicles could be rail vehicles for transporting people or freight, or trams, or handling vehicles traveling on dedicated tracks without rails.
- the markers could be optical markers detected by an optical sensor, mechanical markers detected by feelers or equivalent sensors, radiofrequency tags, etc.
- the solution described below is advantageous because the markers are particularly robust, easy to install and replace on the guideway, economical and resistant to vandalism because of low market value, and easy to firmly attach to the track.
- the inductive characteristic is also advantageous because it does not require contact or special atmospheric conditions. Detection is robust irrespective of the lighting, humidity or pollution conditions, and withstands most forms of jamming.
- FIG. 1 shows the environment of the present disclosure, namely a vehicle ( 1 ) moving on rails ( 10 , 20 ).
- the rails ( 10 , 20 ) have markers that can be attached to the crosspieces, attached to the rail or placed on a fixed support relative to the rail ( 10 , 20 ).
- These markers ( 101 to 104 ) are passive, i.e., they are not supplied with energy.
- the length of the markers ( 101 to 104 ) along the axis of movement of the vehicle ( 1 ) on the rail is variable.
- the markers ( 101 to 104 ) must be located far enough from the rail to avoid disturbances.
- the markers ( 101 to 104 ) can be positioned inside or outside the rails ( 10 , 20 ). It is also possible to arrange several rows of markers ( 101 to 104 ) on the track. In the figure, the markers ( 101 to 104 ) are positioned, for example, along the left rail ( 10 ).
- the rail vehicle ( 1 ) has at least one inductive sensor ( 21 ) positioned above the row of metal markers (which may be magnetic or metal pads). If several rows of markers are present, the rail vehicle ( 1 ) has at least as many inductive sensors ( 21 ).
- the rail vehicle ( 1 ) also has a means of obtaining speed information, for example, using a toothed wheel speed sensor ( 22 ) as shown in FIG. 1 , or by any other means (GPS data, speed obtained by an engine speed observer, coupling between several speed sensors, etc.). This speed information must be sampled sufficiently to be refreshed several times during the passage of the vehicle ( 1 ) above a marker ( 101 to 104 ).
- the property retained namely the length
- lengths of between 50 and 300 millimeters can be provided, with a tolerance of 10 mm (or a relative tolerance), and a segmentation into six classes:
- these markers take the form of a rectangular steel metal pad that can be screwed or glued to a crosspiece of a track segment, between the two rails ( 10 , 20 ), in an identical lateral position for each marker, for example, X centimeters from the left rail ( 20 ).
- markers ( 101 to 104 ) are randomly distributed along the track.
- the property (length) of the marker to be implanted is determined without a predictive model, by a random draw or possibly by a chaotic sequence generator.
- each crosspiece 11 to 16
- a marker on each crosspiece ( 11 to 16 )
- omitting one or more crosspieces does not prevent the proper functioning of embodiments of the present disclosure.
- the presence of a parasitic metal mass, for example, a metal can, on the track does not prevent the correct operation of the system.
- Randomization means that the properties of two consecutive markers are chosen at random. Thus, a class C2 marker will be between any two markers of class C i and C j .
- the sequence of classes on the track is recorded in an ordered database. It can be a simple ordered list of the property of successive markers, of type C4, C2, C3, C4, . . . for a sequence formed by a marker ( 101 ) of 200 mm followed by a marker ( 102 ) of 100 mm, followed by a marker ( 103 ) of 150 mm, followed by a marker ( 104 ) of 200 mm, etc.
- the markers are distributed with an approximately constant spacing, it is not necessary to record the location coordinates of each of the markers, the positioning being able to be deduced from its rank in the ordered list.
- an alternative involves recording the property and position of each marker in the database, for example, by reference to an origin position constituting the zero point, in the form of its distance with respect to this origin point according to a trajectory following the center line of the guideway.
- This implantation of the markers ( 101 to 104 ) on the guideway will form a virtual “coded” line ( 50 ) formed by an alternating presence and absence of the characteristic read by the vehicle, with variable properties alternating with absences of the characteristic, which are also variable.
- the vehicle ( 1 ) comprises an inductive sensor ( 21 ) formed by, for example, a component placed under the chassis of the vehicle and comprising a first winding powered by an alternating current to emit a magnetic field.
- an inductive sensor 21
- a conductive or magnetically permeable target in particular, a marker ( 101 to 104 )
- the impedance of the winding varies, and the measurement of this impedance and of the exceeding of a threshold value makes it possible to generate a binary signal indicating the presence or absence of metallic mass.
- Inductive sensors produce an oscillating magnetic field at the end of their detection head. This field is generated by an inductor and a capacitor mounted in parallel. When a metallic conductive body is placed in this field, eddy currents arise in the mass of the metal; there is disturbance of this field that leads to a reduction in the amplitude of the oscillations as the metal object approaches, until complete blockage occurs. This variation is exploited by an amplifier that delivers a binary output signal.
- variable inductance and variable reluctance sensors generally produce an electrical signal proportional to the conductive mass and the distance of a conductive or magnetically permeable object with respect to a coil.
- the sensor ( 21 ) When the vehicle is stationary, the sensor ( 21 ) remains in the same state depending on the presence or absence of a marker under the vehicle ( 1 ), and more precisely under the head of the sensor ( 21 ).
- the instantaneous movement speed of the vehicle ( 1 ) is known by, for example, an odometric sensor ( 22 ) or any other usual means for measuring the instantaneous speed of a vehicle.
- an odometric sensor ( 22 ) or any other usual means for measuring the instantaneous speed of a vehicle.
- the time interval separating a falling edge and a rising edge of the signal supplied by the inductive sensor ( 21 ), and the distance D 2 separating two consecutive markers ( 101 , 102 ) is determined.
- sequences taken into account have a length of N markers, such that the sequences of length N (or greater than N) produced are orthogonal or quasi-orthogonal in the sense that:
- N is determined according to the total number of markers, the number of property classes by a combinatorial calculation. For example, with the six classes of lengths referred to above, and sequences of 10 consecutive markers, one has a million unique sequences.
- FIG. 2 shows the timing diagram of the signals supplied by the two sensors ( 21 , 22 ) present on the vehicle ( 1 ):
- the odometer comprises an incremental encoder ( 22 ) that counts the number of revolutions of the wheel with a certain precision (typically 100 pitches per revolution: one pitch is approximately equal to 12 mm) and supplies a rectangular signal ( 30 ) whose periodicity is representative of the instantaneous speed.
- the periodicity is constant when the vehicle ( 1 ) is moving at a constant speed.
- the inductive sensor ( 21 ) provides a second rectangular signal ( 40 ) whose level is 1 if it is above a marker ( 101 to 104 ) and zero otherwise.
- the combination of the two sensors makes it possible to measure the length of the markers in number of pitches as well as the distance between markers in number of pitches.
- An electronic system makes it possible to store these two lengths d 1 and d 2 in a memory of adjustable size.
- the circuit is known in advance and recorded in another reference memory that will allow the electronics to define its position.
- FIGS. 3 to 7 illustrate an example of acquisition of the signals from the sensors ( 21 ) and ( 22 ).
- the values are in fact recorded in memory in binary (for example, on 8 bits) in a shift register composed of N values, N corresponding to the number of measurements taken into account in a sliding window of N increments, and recorded in a memory of FIFO type.
- This processing requires very few resources and can be executed by a very simple microcontroller.
- FIG. 8 shows how reading a succession of markers of different lengths L 1 to L 4 makes it possible to find the position P 1 to P 7 of the vehicle ( 1 ) on the guideway.
- the set of markers ( 101 to 104 ) of different lengths forms a set of accessible states with knowledge of the possible transitions between states.
- the read lengths of markers ( 101 to 104 ) correspond to the succession of past markers ( 101 to 104 ) modified by the measurement error.
- These read marker lengths ( 101 to 104 ) are the input data of the positioning algorithm ( 60 ).
- the algorithm finds the most probable state P 3 (Step 65 ) among the known possible states (Step 61 ), and therefore the position (Step 66 ) of the mobile on track.
- this determination can be made in two ways:
- This positioning system can be adapted or supplemented with the distance measurement between two markers ( 101 to 104 ).
- the positioning algorithm takes as input data can be completed to use as input data the distance between two markers ( 101 to 104 ) in addition to the length of the markers ( 101 to 104 ).
- This algorithm can also be adapted to use only the distance between markers ( 101 to 104 ).
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Train Traffic Observation, Control, And Security (AREA)
- Electric Propulsion And Braking For Vehicles (AREA)
Abstract
A system for the geolocation of vehicles traveling on a guideway comprises the vehicles and markers distributed episodically along the guideway. The vehicles are equipped with a sensor for detecting a physical characteristic of the markers, and a computer for supplying location information as a function of signals delivered by the sensor. The computer stores a database comprising a recording of the distribution of the markers on the guideway. The markers having a physical characteristic detectable by the sensors. The markers each belong to one and only one class among a plurality of classes of physical objects, and the physical characteristic of all the markers of a class have the same property during detection by one of the sensors. The markers are randomly distributed on the guideway, with an ordered recording of the class to which each of the markers arranged on the guideway is stored in the database. Each of the recordings is associated with location information relative to the physical position of the marker on the guideway.
Description
- This application claims the benefit of the filing date of French Patent Application Serial No. FR2200366, filed Jan. 17, 2022, for “METHOD FOR LOCATING AND/OR MEASURING THE SPEED OF A VEHICLE.”
- The present disclosure relates to a method for locating and/or measuring the speed of a vehicle moving along a guideway, for example, a railway track formed by two rails, and to a device equipping such a vehicle, in particular, an autonomous shuttle. To improve the traffic conditions of a fleet of shuttles, subway trains, a fleet of autonomous handling vehicles, or trains on a railway network, as well as the safety of all traffic, it is necessary to know the precise speed and location (position) of each vehicle on the guideway.
- Satellite geolocation systems consisting in calculating the current position on the earth's surface, using signals emitted by a constellation of satellites provided for this purpose, are not suitable for vehicles that, for security reasons, require precise and robust positioning with continuous availability. The accuracy of GPS systems remains dependent on meteorological conditions and disruptive geographical elements (proximity to dense vegetation, for example). Availability is not guaranteed when the vehicle crosses an area without radio frequency coverage, for example, a tunnel or underground, deep valleys or urban corridors. Finally, these systems may be subject to malicious acts of jamming, or interruption of service.
- In the rail sector, the development of traffic monitoring and management systems may be required to meet the requirements of standard setting organizations, such as the European Rail Traffic Management System (ERTMS), which aims to harmonize signaling and speed control for rail transport in Europe and, therefore, to make train traffic safer.
- A mobile device is therefore usually positioned on a rail, in particular, according to the CBTC [IEEE 1474] and ERTMS [Annex A of the CCS TSI—SUBSET 026] recommendations by two redundant techniques:
-
- An on-board odometric system that measures the distance traveled, allowing relative location; the odometric system of a mobile on rail is commonly carried out from a measurement of the speed of rotation of one or more wheels. Its precision is then intrinsically limited by the wheel-rail contact and the phenomenon of micro-slip, or even slip, that occurs there. Because of this, there may be a discrepancy between the speed of the wheel and the movement speed of the train, which prevents precise positioning from the odometer system alone.
- GPS geolocation or occasional communication between the train and the track balises, allowing absolute location. The balises are electrically powered to be able to transmit location information, or data provided by an inertial unit or accelerometers.
- To improve the accuracy of train position measurements, it has been proposed to “recalibrate” position measurements obtained from odometry sensors with ground systems, in the form of transmitters/balises (called “Eurobalises”) that are fixed at regular intervals (every 1.5 km on average, in Belgium, for example) on the railway track. Such a balise is activated when the train passes and transmits its exact location to the latter with respect to an absolute reference frame linked to the track. The train's on-board computer then corrects the train's position error by resetting the position given by odometry with the position of the last balise encountered.
- A drawback of this solution is that the balises are placed on the track between the rails. Without supervision, they are thus vulnerable to acts of vandalism. They are also subjected to relatively high mechanical stresses when a train passes, which can cause failures. Apart from the cost generated by the maintenance of these balises, there is also a cost linked to the installation of these balises on the entire rail network and to stock management. In addition, this solution poses a security problem, since if a balise were to no longer operate, the interval between two readjustments of position measurements from the odometry sensors would be increased.
- Some solutions seek to make the odometry system more robust by no longer relying on a wheel rotation measurement. They propose using the track as a regularly spaced magnetic strip by equipping the mobile on rail with a magnetic sensor. Reading the magnetic strip makes it possible to measure the movement speed and the position variation with greater precision than odometry systems based on the wheel speed [DE2164312]. Such a solution, however, requires having a magnetic marker on the entire network while respecting the very strong positioning constraints of these markers in order to guarantee the regularity of the spacing.
- Another solution for measuring the “distance traveled” of a train is described in patent document FR2673901. This solution involves fixing magnetizable strips all along the railway track and in implementing, with respect to the movement direction of the vehicle, at least one magnetic marking coil for such strips, powered by a pulse generator electric current and located on the front bogie of the locomotive, and at least one detector of this magnetic marking on the rear bogie of the locomotive, the coil and the detector being separated by a predetermined distance from each other. Means are also provided for ordering a new marking after each detection as well as means for counting the number of detected markings representative of the distance traveled by the locomotive (and therefore the position of the locomotive on the railway track). The basic idea of FR2673901 involves carrying out a magnetic marking of a magnetizable strip of the track, preferably one of the rails, and repeating this marking each time a predetermined distance has been traveled and measured.
- It is also known to implement an image capture device placed at one end of the train, the images being subsequently analyzed to determine the speed and position of the train; see, for example, document US 2007/0282563. The analysis of the images involves identifying elements, such as bar codes placed on the ground, along the track, at locations known a priori, and comparing the identified codes with codes stored in a database, making it possible to spatially locate the train; see, for example, document WO 2007/091072.
- Solutions based on inductive reading of markers are interesting because they are generally insensitive to atmospheric conditions, unlike solutions based on optical reading or on radio frequency data exchange, which are robust because inductive reading is done by an electromagnetic coil that does not require any maintenance and that withstands vibrations, impacts and physical aggressions of all kinds with no problems, and uses inexpensive solutions to exploit the signals.
- Known in the state of the art is US patent U.S. Pat. No. 8,067,933B2 relating to a device for locating a vehicle associated with a track, comprising reference marks, which are placed on the track, and detection means arranged in the vehicle, which produce at least one output signal when passing a reference mark. The detection means are composed of several individual sensors that extend in the direction of travel with an average detection length greater than or equal to the distance between neighboring reference marks.
- Also known from patent EP2065288 is a railroad positioning system provided with an on-board speed measuring device inducing eddy currents in the track structure, at two places along the direction of travel, measuring the variations in the magnetic field emitted by the track structure and determining position and speed by correlating the two measured signals and a coded track tag providing coding recognizable by the on-board speed measuring device. An embodiment proposed by this document concerns the use of coded tags consisting of a bar with several slots in which metal blocks of different sizes are mounted. Block sizes and positions are selected to represent Quadrature Amplitude Modulation coding.
- Patent FR3055876 relates to a method for determining the position of a railway vehicle traveling on a railway track provided with a plurality of structural elements each comprising a device for storing identification data, comprises a prior step of obtaining a data sequence so as to form a list of data sequences each successively identifying a successive structural element. This method also comprises steps of initialization, during which a data sequence is retrieved; reading the identification data item associated with the structural element over which the vehicle passes; modifying the data sequence as a function of the identification datum; and calculating the position of the vehicle according to the data sequence.
- Application WO01/66401 relates to a device for determining the position of a rail vehicle. This device comprises at least one sensor suitable for generating a signal depending on the irregularities of the railway track caused by the rail components mounted on the railway track or connected thereto; a memory means suitable for storing, on the one hand, information relating to the position of the components of the rail along the path of the vehicle and, on the other hand, characteristics necessary for identifying the components of the rail; an identification means suitable for detecting and identifying the components of the rail by comparing the signal with the stored characteristics; a calculating means designed to determine the position of the vehicle from the identified rail components and their stored position. The invention thereof also relates to a method for determining the position of a rail vehicle. According to this method, the position and the characteristics of the components of the rail mounted on the railway track or connected thereto are previously recorded and stored. A signal is produced based on the irregularities caused by these components. The signal is compared to the characteristics, whereby the rail components are detected and identified, and the position of the vehicle is determined from the identified rail components and their stored position.
- Patent application DE102019118767 relates to a method for detecting the position of a railway vehicle on a railway track, as well as a railway track designed to implement such a method. The position of the railway vehicles is detected by way of a sensor of the vehicle that detects, during its passage on the railway track, a sequence of magnetic fields generated by magnets arranged on the railway track and generates, from the variations of the resulting magnetic field, a binary model whose data content represents a local coordinate of the railway track.
- The solutions of the prior art have several drawbacks.
- First, the equipment of a set of guideways can constitute a considerable investment, and mobilization of multiple resources may be required to configure the markers installed on the network, which constitute a database whose maintenance and updating represent considerable work in themselves.
- Secondly, the processing operations to be carried out in order to know the position in real time are often very cumbersome and require significant computing power.
- In its most general sense, the present disclosure relates to a system for the geolocation of vehicles traveling on a guideway comprising:
-
- a) vehicles equipped with a sensor for detecting a physical characteristic of markers distributed episodically on the guideway, as well as a computer for supplying location information as a function of the signals delivered by the sensor, and a database comprising the recording of the distribution of the markers on the guideway, and
- b) markers having a physical characteristic detectable by the sensors, distributed over the guideway;
- characterized in that,
-
- the markers each belong to one and only one class among a plurality of classes of physical objects, the physical characteristic of all the objects of a class having the same property during detection by one of the sensors, and
- the markers are randomly distributed on the guideway, with an ordered recording of the class to which each of the markers arranged on the guideway belongs in a database, each of the recordings being associated with location information relative to the physical position of the marker on the guideway.
- As used herein, the term “randomly” means that the choice of the property of each of the markers distributed on the track is established without an identifiable prediction rule, for example, by the result of chance or of a chaotic sequence generator.
- According to a preferred embodiment, the physical characteristic is magnetic induction.
- Advantageously, the markers are conductive masses and the sensors comprise a transmitter coil powered by an alternating electric current and by a receiver coil detecting the magnetic field induced by a conductive marker to produce an electric current processed to provide a signal when in proximity to a conductive marker.
- Preferably, the markers are magnetic masses and the sensors are constituted by a receiver coil detecting the magnetic field induced by a magnetic marker to produce an electric current processed to provide a signal when in proximity to a magnetic marker.
- Preferably, the physical property is the length in the direction of the trajectory of the vehicle on the guideway, and the membership classes correspond to ranges of length with no overlap between the ranges.
- Preferably, the physical property is the length in the direction of the trajectory of the vehicle on the guideway, and the membership classes correspond to ranges of length with no overlap between the ranges.
- Advantageously, the markers are positioned between the rails forming the guideway.
- According to a particular embodiment, the database also comprises the recordings of the distances separating two consecutive markers.
- Advantageously, the distribution of the markers on the guideway is periodic.
- Preferably, the vehicles further comprise a second geolocation means, the computer applying a consistency verification process between the geolocation information supplied by the sensor and the information supplied by the second geolocation means.
- The present disclosure also relates to a method for geolocating vehicles equipped with a sensor for detecting a physical characteristic of markers, traveling on a guideway comprising a distribution of markers having a physical characteristic detectable by the sensors, characterized in that the method comprises recording, during the movement, a sliding window of the property of each of the markers detected by the sensor of the vehicle, and in comparing the sequence recorded during the movement of the vehicle with the sequences recorded in a database containing an ordered recording of the class to which each of the markers arranged on the guideway belongs in a database, each of the recordings being associated with location information relative to the physical position of the marker on the guideway.
- Advantageously, after processing a sequence of properties read by the sensor, the following is carried out:
-
- Recording in a buffer memory of the following sequence recorded in the database,
- Recording in a buffer memory of the previous sequence shifted by the reading by the sensor of the property of the next marker,
- Comparing these two sequences to validate the location in the event of conformity or to order signaling in the event of a difference.
- The present disclosure will be described in more detail with reference to non-limiting example embodiments specifying the aforementioned advantages and considerations. A more specific description of the present disclosure is illustrated by the accompanying drawings, where:
-
FIG. 1 shows a schematic view of a section of guideway according to the present disclosure; -
FIG. 2 shows a view of the sequences of signals processed by the computer; -
FIG. 3 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a first position; -
FIG. 4 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a second position; -
FIG. 5 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a third position; -
FIG. 6 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a fourth position; -
FIG. 7 shows a schematic view of a section of guideway with a vehicle according to the present disclosure in a fifth position; and -
FIG. 8 shows a schematic view of the digital processing operations. - The positioning system will be described below according to a non-limiting example where the markers are metallic masses, the physical property taken into account is the length along the trajectory of the vehicle (1), and the sensors are inductive sensors and autonomous shuttle vehicles traveling on a dedicated track with guide rails. The vehicles are also equipped, according to a preferred option, with a second location system, for example, an odometer taking into account the rotation of one of the wheels of the vehicle, or possibly radio transmitter balises arranged along the guideway, or even a GPS system, the data of which in the uncovered area will be extrapolated from data provided by, for example, an inertial unit.
- The guideway can form a single closed loop, or on the contrary have multiple branches.
- This detailed description that follows may be directly transposed to other implementations, which form an integral part of the present disclosure: for example, the vehicles could be rail vehicles for transporting people or freight, or trams, or handling vehicles traveling on dedicated tracks without rails. The markers could be optical markers detected by an optical sensor, mechanical markers detected by feelers or equivalent sensors, radiofrequency tags, etc.
- Embodiment with metal markers and an inductive sensor
- The solution described below is advantageous because the markers are particularly robust, easy to install and replace on the guideway, economical and resistant to vandalism because of low market value, and easy to firmly attach to the track.
- The inductive characteristic is also advantageous because it does not require contact or special atmospheric conditions. Detection is robust irrespective of the lighting, humidity or pollution conditions, and withstands most forms of jamming.
-
FIG. 1 shows the environment of the present disclosure, namely a vehicle (1) moving on rails (10, 20). The rails (10, 20) have markers that can be attached to the crosspieces, attached to the rail or placed on a fixed support relative to the rail (10, 20). These markers (101 to 104) are passive, i.e., they are not supplied with energy. The length of the markers (101 to 104) along the axis of movement of the vehicle (1) on the rail is variable. - The markers (101 to 104) must be located far enough from the rail to avoid disturbances. The markers (101 to 104) can be positioned inside or outside the rails (10, 20). It is also possible to arrange several rows of markers (101 to 104) on the track. In the figure, the markers (101 to 104) are positioned, for example, along the left rail (10).
- The rail vehicle (1) has at least one inductive sensor (21) positioned above the row of metal markers (which may be magnetic or metal pads). If several rows of markers are present, the rail vehicle (1) has at least as many inductive sensors (21).
- The rail vehicle (1) also has a means of obtaining speed information, for example, using a toothed wheel speed sensor (22) as shown in
FIG. 1 , or by any other means (GPS data, speed obtained by an engine speed observer, coupling between several speed sensors, etc.). This speed information must be sampled sufficiently to be refreshed several times during the passage of the vehicle (1) above a marker (101 to 104). - According to this embodiment described in detail, the property retained, namely the length, is also advantageous because it is easy to segment the assembly into classes of lengths without overlap, while accepting a tolerance for manufacturing and for reading. For example, lengths of between 50 and 300 millimeters can be provided, with a tolerance of 10 mm (or a relative tolerance), and a segmentation into six classes:
-
- C1 [40 mm to 60 mm]
- C2 [90 mm to 110 mm]
- C3 [140 mm to 160 mm]
- C4 [190 mm to 210 mm]
- C5 [240 mm to 260 mm]
- C6 [290 mm to 310 mm]
- It is easy to read the “length” property by an inductive sensor detecting the presence or absence of a metallic mass, combined with a determination of the length as a function either of a movement sensor, for example, odometric, or as a function of the speed and the time elapsing between a rising edge and a falling edge of magnetic flux detection.
- Physically, these markers take the form of a rectangular steel metal pad that can be screwed or glued to a crosspiece of a track segment, between the two rails (10, 20), in an identical lateral position for each marker, for example, X centimeters from the left rail (20).
- These markers (101 to 104) are randomly distributed along the track.
- The property (length) of the marker to be implanted is determined without a predictive model, by a random draw or possibly by a chaotic sequence generator.
- To obtain a high resolution, it is preferable to provide a marker on each crosspiece (11 to 16), but omitting one or more crosspieces does not prevent the proper functioning of embodiments of the present disclosure. Similarly, the presence of a parasitic metal mass, for example, a metal can, on the track does not prevent the correct operation of the system.
- Randomization means that the properties of two consecutive markers are chosen at random. Thus, a class C2 marker will be between any two markers of class Ci and Cj.
- The sequence of classes on the track is recorded in an ordered database. It can be a simple ordered list of the property of successive markers, of type C4, C2, C3, C4, . . . for a sequence formed by a marker (101) of 200 mm followed by a marker (102) of 100 mm, followed by a marker (103) of 150 mm, followed by a marker (104) of 200 mm, etc.
- It is not necessary for two or more markers to belong to different classes.
- Moreover, when the markers are distributed with an approximately constant spacing, it is not necessary to record the location coordinates of each of the markers, the positioning being able to be deduced from its rank in the ordered list.
- To facilitate exploitation, however, an alternative involves recording the property and position of each marker in the database, for example, by reference to an origin position constituting the zero point, in the form of its distance with respect to this origin point according to a trajectory following the center line of the guideway.
- This implantation of the markers (101 to 104) on the guideway will form a virtual “coded” line (50) formed by an alternating presence and absence of the characteristic read by the vehicle, with variable properties alternating with absences of the characteristic, which are also variable.
- Assuming that the inter-distance between two crosspieces is constant, and that each crosspiece (11 to 16) carries a marker, the sum between the presence and the absence of induction will correspond to a constant length, and will provide the sensor (21) of the vehicle (1) traveling on the track with information coded according to a pulse width modulation (PWM) technique, commonly used to exploit robust discrete state signals.
- The vehicle (1) comprises an inductive sensor (21) formed by, for example, a component placed under the chassis of the vehicle and comprising a first winding powered by an alternating current to emit a magnetic field. When a conductive or magnetically permeable target, in particular, a marker (101 to 104), is close to the winding, the impedance of the winding varies, and the measurement of this impedance and of the exceeding of a threshold value makes it possible to generate a binary signal indicating the presence or absence of metallic mass.
- Inductive sensors produce an oscillating magnetic field at the end of their detection head. This field is generated by an inductor and a capacitor mounted in parallel. When a metallic conductive body is placed in this field, eddy currents arise in the mass of the metal; there is disturbance of this field that leads to a reduction in the amplitude of the oscillations as the metal object approaches, until complete blockage occurs. This variation is exploited by an amplifier that delivers a binary output signal.
- Those skilled in the art know multiple solutions of variable inductance and variable reluctance sensors generally produce an electrical signal proportional to the conductive mass and the distance of a conductive or magnetically permeable object with respect to a coil.
- When the vehicle is stationary, the sensor (21) remains in the same state depending on the presence or absence of a marker under the vehicle (1), and more precisely under the head of the sensor (21).
- When the vehicle (1) moves at a speed V, the sensor (21) will detect a marker n whose “property” is a length L for a duration Ti=Li/V.
- The instantaneous movement speed of the vehicle (1) is known by, for example, an odometric sensor (22) or any other usual means for measuring the instantaneous speed of a vehicle. By measuring the time interval Ti separating a rising edge and a falling edge of the signal supplied by the inductive sensor (21), the property of the marker is determined, namely its length Li equal to Ti/V.
- Similarly, the time interval separating a falling edge and a rising edge of the signal supplied by the inductive sensor (21), and the distance D2 separating two consecutive markers (101, 102) is determined.
- The sequences taken into account have a length of N markers, such that the sequences of length N (or greater than N) produced are orthogonal or quasi-orthogonal in the sense that:
-
- Any sub-sequence extracted from the total sequence is unique, thus ensuring the uniqueness of positioning.
- Any subsequence extracted from the total sequence exhibits minimal correlation with all other subsequences, thus ensuring robustness to measurement inaccuracies.
- See, for example, Dines, L. L. “A Theorem on Orthogonal Sequences.” Transactions of the American Mathematical Society, vol. 30, no. 2, American Mathematical Society, 1928, pp. 439-46, https://doi.org/10.2307/1989131.
- N is determined according to the total number of markers, the number of property classes by a combinatorial calculation. For example, with the six classes of lengths referred to above, and sequences of 10 consecutive markers, one has a million unique sequences.
-
FIG. 2 shows the timing diagram of the signals supplied by the two sensors (21, 22) present on the vehicle (1): - The odometer comprises an incremental encoder (22) that counts the number of revolutions of the wheel with a certain precision (typically 100 pitches per revolution: one pitch is approximately equal to 12 mm) and supplies a rectangular signal (30) whose periodicity is representative of the instantaneous speed. The periodicity is constant when the vehicle (1) is moving at a constant speed.
- The inductive sensor (21) provides a second rectangular signal (40) whose level is 1 if it is above a marker (101 to 104) and zero otherwise.
- The combination of the two sensors makes it possible to measure the length of the markers in number of pitches as well as the distance between markers in number of pitches.
- An electronic system makes it possible to store these two lengths d1 and d2 in a memory of adjustable size. The circuit is known in advance and recorded in another reference memory that will allow the electronics to define its position.
-
FIGS. 3 to 7 illustrate an example of acquisition of the signals from the sensors (21) and (22). - In
FIG. 3 , the vehicle (1) passes over the first marker (102): it measures d1=10 pitches (approximately 12 cm) and stores the value (10 pitches) in memory in a first register. - In
FIG. 4 , the vehicle (1) passes over the start of the second marker (103): it measures d2=154 pitches (approximately 185 cm) and stores the value (154 pitches) in memory in a second register. - In
FIG. 5 , the vehicle (1) passes over the end of the second marker (103): it measures d1=5 pitches (approximately 6 cm) and stores the value (5 pitches) in memory in a third register. - In
FIG. 6 , the vehicle (1) passes over the start of the third marker (104): it measures d2=150 pitches (approximately 180 cm) and stores the value (154 pitches) in memory in a fourth register. - And so on.
- The values are in fact recorded in memory in binary (for example, on 8 bits) in a shift register composed of N values, N corresponding to the number of measurements taken into account in a sliding window of N increments, and recorded in a memory of FIFO type. This processing requires very few resources and can be executed by a very simple microcontroller.
- One then proceeds to a process involving a hash of these data: Only the most representative values are kept to form a binary word on N bits (for example, a word on 32 bits) to produce a binary sequence coding the absolute position of the capsule (deletion of useless bits).
- During synchronization (search for the initial state during start-up), the closest binary word is searched in the table compared with the table. This synchronization involves validating the position resulting from the exploitation of the signals supplied by the sensors (21, 22) making it possible to calculate sliding sequences, with the sequences recorded in the database constituted during the implantation of the markers or during a reset step.
- Once synchronized, it is checked at the next pad that the read state is close to the expected state. To do this, it suffices to read the following sequence in the table and to check, during the acquisition of the signals, that the sequence obtained by the exploitation of the signals from the sensors (21, 22) is compliant. It is thus possible to produce location information very simply by incremental reading of the positions recorded in the database, by synchronizing with the signals supplied by the sensors (21, 22).
-
FIG. 8 shows how reading a succession of markers of different lengths L1 to L4 makes it possible to find the position P1 to P7 of the vehicle (1) on the guideway. The set of markers (101 to 104) of different lengths forms a set of accessible states with knowledge of the possible transitions between states. The read lengths of markers (101 to 104) correspond to the succession of past markers (101 to 104) modified by the measurement error. These read marker lengths (101 to 104) are the input data of the positioning algorithm (60). From the measurements (Step 62) and knowledge of the positioning (Step 63) of the markers (101 to 104) on the guideway, the algorithm (Step 64) finds the most probable state P3 (Step 65) among the known possible states (Step 61), and therefore the position (Step 66) of the mobile on track. - Depending on the algorithm used, this determination can be made in two ways:
-
- by memorizing a fixed number of markers and finding this pattern in the set of existing patterns. In this case, the algorithm can be, for example, a search for a maximum in a convolution calculation, or any other method making it possible to find the sequence produced in a deterministic manner.
- by a probabilistic method giving the probability of being located at each point of the network or only the most probable point. The use of a probabilistic algorithm for determining the state may be, for example, a Viterbi algorithm, a Kalman filter, or any other method making it possible to find the sequence carried out in the most probable manner.
- The successive steps of positioning on the track are therefore:
-
- 1. Detecting the presence of markers (101 to 104).
- 2. Coupling the speed measurement with the detection of the presence of markers (101 to 104) in order to determine the length of the markers (101 to 104). This speed measurement can come from a wheel rotation speed sensor or from any other method of obtaining a sufficiently sampled speed measurement to allow the length of the crosspiece to be measured, for example, coupling the speed measurements of several axles, a speed measurement given by a GPS, a speed obtained by an engine speed observer, etc.
- 3. Reading the succession of markers (101 to 104) in order to define a succession of words in a code.
- 4. Using this succession of words to determine the markers (101 to 104) read in the entire network code. This determination can be made in two ways, either by memorizing a fixed number of markers (101 to 104) and finding this pattern in all the existing patterns, or by a probabilistic method giving the probability of being located in each network point.
- 5. Linking the position in the code to the absolute position on the network.
- This positioning system can be adapted or supplemented with the distance measurement between two markers (101 to 104). In this case, the positioning algorithm takes as input data can be completed to use as input data the distance between two markers (101 to 104) in addition to the length of the markers (101 to 104). This algorithm can also be adapted to use only the distance between markers (101 to 104).
Claims (20)
1. A system for the geolocation of vehicles traveling on a guideway, comprising:
vehicles equipped with a sensor for detecting a physical characteristic of markers distributed episodically on the guideway, and a computer for supplying location information as a function of the signals delivered by the sensor and storing a database comprising a recording of a distribution of the markers on the guideway; and
markers having a physical characteristic detectable by the sensors, the markers distributed over the guideway;
wherein,
the markers each belong to one and only one class among a plurality of classes of physical objects, the physical characteristic of all the markers of a class having the same property during detection by one of the sensors, and
the markers are randomly distributed on the guideway, with an ordered recording of the class to which each of the markers arranged on the guideway belongs in the database, each of the recordings being associated with location information relative to the physical position of the marker on the guideway.
2. The system of claim 1 , wherein the physical characteristic is magnetic induction.
3. The system of claim 2 , wherein the markers are conductive masses and the sensors comprise a transmitter coil powered by an alternating electric current and by a receiver coil detecting the magnetic field induced by a conductive marker to produce an electric current processed to provide a signal when in proximity to a conductive marker.
4. The system of claim 2 , wherein, the markers are magnetic masses and the sensors are constituted by a receiver coil detecting the magnetic field induced by a magnetic marker to produce an electric current processed to provide a signal when in proximity to a magnetic marker.
5. The system of claim 1 , wherein the physical property is a length in a direction of a trajectory of the vehicle on the guideway.
6. The system of claim 5 , wherein the classes of the plurality of classes correspond to ranges of the length with no overlap between the ranges.
7. The system of claim 6 , wherein the markers are positioned between the rails forming the guideway.
8. The system of claim 7 , wherein the database also comprises the recordings of distances separating two consecutive markers.
9. The system of claim 8 , wherein the distribution of the markers on the guideway is periodic.
10. The system of claim 9 , wherein the vehicles further comprise a second geolocation means, and the computer is configured to apply a consistency verification process between geolocation information calculated as a function of the signals delivered by the sensor and information supplied by the second geolocation means.
11. A method for geolocating vehicles equipped with a sensor for detecting a physical characteristic of markers, traveling on a guideway comprising a distribution of markers having a physical characteristic detectable by the sensors, wherein in the method comprises recording, during the movement, a sliding window of the property of the physical characteristic of each of the markers detected by the sensor of the vehicle, and comparing the sequence recorded during the movement of the vehicle with the sequences recorded in a database containing an ordered recording of the class to which each of the markers arranged on the guideway belongs in a database, each of the recordings being associated with location information relative to the physical position of the marker on the guideway.
12. The method of claim 11 , further comprising, after processing a sequence of properties read by the sensor:
recording in a buffer memory of the following sequence recorded in the database,
recording in a buffer memory of the previous sequence shifted by the reading by the sensor of the property of the next marker, and
comparing these two sequences to validate the location in the event of conformity or to order signaling in the event of a difference.
13. The system of claim 1 , wherein the markers are positioned between the rails forming the guideway.
14. The system of claim 1 , wherein the database also comprises recordings of distances separating two consecutive markers.
15. The system of claim 1 , wherein the distribution of the markers on the guideway is periodic.
16. The system of claim 1 , wherein the vehicles further comprise a second geolocation means, and the computer is configured to apply a consistency verification process between geolocation information calculated as a function of the signals delivered by the sensor and information supplied by the second geolocation means.
17. A system for geolocation of vehicles traveling on a guideway, comprising:
markers distributed along the guideway, each of the markers having a common physical characteristic that varies among the markers, each marker belonging to one and only one class among a plurality of classes correlated to variations of the common physical characteristic, the sequence of categories of markers along the guideway being random; and
at least one vehicle configured to travel along the guideway, the at least one vehicle comprising:
a sensor configured to detect the physical characteristic of each of the markers as the vehicle passes adjacent the respective marker; and
a computer configured to receive a signal from the sensor, the signal corresponding to the detected physical characteristic, and to identify the category to which each marker respectively belongs as the vehicle passes adjacent the respective marker, the computer configured to record sequences of the detected categories of markers identified by the computer, the computer further storing the random sequence of categories of markers along the guideway, the computer configured to compare the recorded sequences with the stored random sequence of categories of markers along the guideway and determine a location of the vehicle along the guideway.
18. The system of claim 17 , wherein the markers are metal members having variable lengths, and wherein the sensor comprises a sensor configured to detect the presence of the metal members in proximity thereto.
19. The system of claim 18 , wherein the vehicle further comprises a speed sensor for determining a speed of the vehicle, and wherein the computer is configured to use the determined speed of the vehicle and the sensor to determine the length of each metal member as the vehicle passes adjacent each metal member.
20. The system of claim 19 , wherein the speed sensor comprises a sensor configured to detect a rotational speed of a wheel of the vehicle.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR2200366A FR3131893B1 (en) | 2022-01-17 | 2022-01-17 | METHOD FOR LOCALIZING AND/OR MEASURING VEHICLE SPEED |
FR2200366 | 2022-01-17 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20230227083A1 true US20230227083A1 (en) | 2023-07-20 |
Family
ID=81448382
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US18/155,280 Abandoned US20230227083A1 (en) | 2022-01-17 | 2023-01-17 | Method for locating and/or measuring the speed of a vehicle |
Country Status (3)
Country | Link |
---|---|
US (1) | US20230227083A1 (en) |
EP (1) | EP4212404A1 (en) |
FR (1) | FR3131893B1 (en) |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2164312A1 (en) | 1971-12-23 | 1973-06-28 | Siemens Ag | DEVICE FOR TRAVEL AND SPEED MEASUREMENT ON RAIL VEHICLES |
FR2673901B1 (en) | 1991-03-13 | 1994-05-20 | Inrets | METHOD FOR LOCATING A VEHICLE ROLLING ON A GUIDANCE TRACK AND LOCATION INSTALLATION EQUIPPED WITH SUCH A VEHICLE. |
SE0000827L (en) | 2000-03-10 | 2001-09-03 | Daimler Chrysler Ag | Device and method for determining the position of a tracked vehicle |
JP4044808B2 (en) * | 2002-08-13 | 2008-02-06 | 邦博 岸田 | Moving object detection system |
US8426381B2 (en) | 2005-09-09 | 2013-04-23 | Lucas Meyer Cosmetics Canada Inc. | Polysaccharides compositions comprising fucans and galactans and their use to reduce extravasation and inflammation |
GB0602448D0 (en) | 2006-02-07 | 2006-03-22 | Shenton Richard | System For Train Speed, Position And Integrity Measurement |
US7561989B2 (en) | 2006-04-04 | 2009-07-14 | Procise | Extracting performance metrics from images |
DE502006007134D1 (en) | 2006-07-06 | 2010-07-15 | Siemens Ag | DEVICE FOR LOCATING A VEHICLE TIED TO A PATH |
DE602007006677D1 (en) | 2007-11-28 | 2010-07-01 | Bombardier Transp Gmbh | Appeared positioning system |
FR3055876B1 (en) | 2016-09-12 | 2019-07-19 | Alstom Transport Technologies | METHOD FOR DETERMINING THE POSITION OF A RAILWAY VEHICLE AND ASSOCIATED RAILWAY INSTALLATION |
DE102019118767A1 (en) * | 2019-07-11 | 2021-01-14 | Deutsche Bahn Ag | Method for position detection of a rail vehicle on a rail traffic route and rail traffic route, set up to carry out such a method |
-
2022
- 2022-01-17 FR FR2200366A patent/FR3131893B1/en active Active
-
2023
- 2023-01-17 US US18/155,280 patent/US20230227083A1/en not_active Abandoned
- 2023-01-17 EP EP23152027.1A patent/EP4212404A1/en active Pending
Also Published As
Publication number | Publication date |
---|---|
EP4212404A1 (en) | 2023-07-19 |
FR3131893B1 (en) | 2024-04-26 |
FR3131893A1 (en) | 2023-07-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8073581B2 (en) | Efficient data acquisition for track databases | |
US10220863B2 (en) | Guideway mounted vehicle localization system | |
US11254338B2 (en) | Guideway mounted vehicle localization and alignment system and method | |
Weston et al. | Perspectives on railway track geometry condition monitoring from in-service railway vehicles | |
US8296065B2 (en) | System and method for vitally determining position and position uncertainty of a railroad vehicle employing diverse sensors including a global positioning system sensor | |
US9174657B2 (en) | Automated real-time positive train control track database validation | |
US4863123A (en) | Process and system for localizing a mobile unit which travels on a system of railroads | |
US9663128B2 (en) | Location and/or direction of travel detection system and method | |
US8525510B2 (en) | Railway positioning system | |
US8390442B2 (en) | Method and apparatus for real-time location of assets | |
CN107784334A (en) | Rail traffic vehicles Precise Position System based on RFID technique | |
US20020045975A1 (en) | Multi-sensor route detector for rail vehicle navigation | |
CN109800828A (en) | Vehicle positioning system and localization method based on two dimensional code | |
US20040046546A1 (en) | Mobile detection system | |
CN111572598A (en) | High-speed magnetic-levitation train positioning method and system | |
CN110155124A (en) | Train positioning system and method | |
US20230227083A1 (en) | Method for locating and/or measuring the speed of a vehicle | |
CN111243022A (en) | Bottom layer absolute positioning method and positioning system based on track path | |
KR102316770B1 (en) | Train Location Device and Method on railway lines | |
GB2222902A (en) | Railway vehicle location system | |
CN114537481B (en) | Mobile closed train operation control method based on grating array | |
KR101325378B1 (en) | Apparatus for compensating error of train position | |
KR101434314B1 (en) | Train position detecting device using magnet pattern and method thereof | |
EP2985629B1 (en) | System and method for detecting and locating the center of beacons installed along guided vehicle routes | |
CN106515794B (en) | The lasting modification method of train absolute position in subrange |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
AS | Assignment |
Owner name: URBANLOOP, FRANCE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MANGEOT, JEAN-PHILIPPE;LEFEBVRE, GAETAN;BAROCHE, THOMAS;SIGNING DATES FROM 20230329 TO 20230504;REEL/FRAME:063620/0427 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |