Method for locating and/or measuring the speed of a vehicle

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.

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.