Patent Publication Number: US-10324067-B2

Title: Vibration monitoring system and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 14/501,177, filed on Sep. 30, 2014, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     Embodiments of the subject matter disclosed herein relate to monitoring systems and methods. 
     BACKGROUND OF THE INVENTION 
     Some known systems sense vibrations propagating through the ground in order to detect the presence of one or more objects. These systems can examine the vibrations that are sensed in order to attempt to identify the objects, determine where the objects are located, and the like. One example of such systems senses ground vibrations using a fiber optic cable extending beneath or near rail tracks. While these fiber optic cables may have been placed along the rail track to provide network connectivity, some rail companies have the ability to use these fiber optic cables to monitor vibrations in the ground. These vibrations can be used to attempt to identify the passage of rail vehicles along the track. 
     One problem with these known systems is that the systems are not “vital” systems. For example, the systems may be unable to automatically correct changes in sensed vibrations that are caused by external factors. Changes in the weather and other factors may change the vibrations and/or the propagation of vibrations through the ground, and can hinder or block the ability of these systems to accurately identify rail vehicles based on the vibrations that are generated. These systems may suffer from incorrectly detecting a rail vehicle based on vibrations that are not caused by the rail vehicle, but that appear to be caused by a rail vehicle due to the impact of environmental conditions on the propagation of the vibrations. Similarly, these systems may suffer from failing to detect a rail vehicle based on vibrations that are caused by the rail vehicle, but that do not appear to be caused by a rail vehicle due to the impact of environmental conditions on the propagation of the vibrations. 
     Additionally, existing systems typically rely on a one-time calibration of the exact location of the fiber optic cables. Changes in the fiber optic cable or interrogation equipment subsequent to calibration, therefore, can introduce errors into the data utilized to detect vehicles. For example, if the fiber optic cable characteristics or the fiber optic cable itself is moved, data skewing can occur and the accuracy of the system can be affected. Accordingly, there is a need for a system and method that is capable of ensuring that the physic fiber optic cables have not moved, and which can be calibrated to account for any such movements. 
     Moreover, initial configuration and calibration of the existing systems is complex, time-consuming, which implies that the installation of such systems is very long and requires a lot of time and/or many people on site to configure the system. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, the invention concerns a method for detecting the presence of a vehicle on a railway track, using a sensing processor monitoring a sensing system for detecting vibration into ground installed along the railway track and comprising a detection module for detecting a vehicle on the railway track. The method comprises an initialization step comprising the sub-steps of: at an initialization device, emitting a first signal to be received by the sensing processor through the sensing system; at the initialization device, sending to the sensing processor, a first message comprising configuration data chosen among, location of the initialization device, intensity/magnitude of the first signal, emission time of the first signal, type of object corresponding to the first signal; at the sensing processor, monitoring the sensing system; and at the sensing processor, configuring the detection module in function of the received first signal and the received configuration data. 
     Preferred embodiments of the invention are the subject matter of the dependent claims, whose content is to be understood as forming an integral part of the present description. 
     In another embodiment of the invention, the method (e.g., for sensing vibrations) includes introducing baseline vibrations into a fiber optic cable with one or more of a designated frequency or a designated amplitude, monitoring changes in the baseline vibrations using the fiber optic cable, and determining information about environmental conditions outside of the fiber optic cable based at least in part on the changes in the baseline vibrations that are monitored. 
     In another embodiment, the invention concerns a system (e.g., a monitoring system) including a control system and a sensing system. The control system is configured to introduce baseline vibrations into a fiber optic cable with one or more of a designated frequency or a designated amplitude. The sensing system is configured to monitor changes in the baseline vibrations using the fiber optic cable and to determine information about environmental conditions outside of the fiber optic cable based at least in part on the changes in the baseline vibrations that are monitored. 
     In another embodiment, the invention concerns a sensing system includes one or more sensors and one or more sensing processors. The one or more sensors are configured to examine light traveling through a fiber optic cable extending along and beneath a route traveled by vehicles. The one or more sensing processors are configured to monitor changes in baseline vibrations introduced into the fiber optic cable at designated times, and to determine information about environmental conditions outside of the fiber optic cable based at least in part on the changes in the baseline vibrations that are monitored. 
     The invention concerns also a detecting system for detecting the presence of a vehicle on a railway track having the features defined in claim  20 . 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference is made to the accompanying drawings in which particular embodiments and further benefits of the invention are illustrated as described in more detail in the description below, in which: 
         FIG. 1  is a schematic diagram of a vibration monitoring system, i.e. of a detecting system for detecting the presence of a vehicle on a railway track according to one embodiment; 
         FIG. 2  schematically illustrates a sensing system of the detecting system shown in  FIG. 1  during movement of an object of interest according to one embodiment; 
         FIG. 3  illustrates one example of a frequency spectrum of vibrations of interest generated by movement of the object of interest shown in  FIG. 2  as detected by the sensing system shown in  FIG. 1 ; 
         FIG. 4  illustrates a frequency spectrum of baseline vibrations generated by a control system shown in  FIG. 1  during different environmental conditions according to one embodiment; 
         FIG. 5  illustrates a flowchart of a method for monitoring vibrations according to one embodiment; 
         FIG. 6  illustrates a flowchart of a method for verifying the integrity of the vibration monitoring system shown in  FIG. 1 ; 
         FIG. 7  illustrates a flowchart of a method for determining the location status of a calibration device of the vibration monitoring system shown in  FIG. 1 ; 
         FIG. 8  is a schematic diagram of a vibration monitoring system, i.e. of a detecting system for detecting the presence of a vehicle on a railway track according to one embodiment; 
         FIG. 9  illustrates a flowchart of the steps of a method for detecting the presence of a vehicle on a railway track according to one embodiment of the invention realized by the detecting system of  FIG. 8 ; 
         FIG. 10  illustrates a flowchart of the sub-steps of an initialization step of the method of  FIG. 9 ; 
         FIG. 11  illustrates a flowchart of the sub-steps of a security step of the method of  FIG. 9 ; and 
         FIG. 12  illustrates a flowchart of the sub-steps of a control step of the method of  FIG. 9 ; 
         FIG. 13  illustrates a flowchart of the sub-steps of a detecting step of the method of  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One or more embodiments of a vibration monitoring system and method are described herein. These systems and methods can generate vibrations that propagate through a portion of the ground that includes one or more sensing cables. The sensing cable can be used to detect the vibrations. As one example, a fiber optic cable can be used as the sensing cable, with changes in refraction of light in the fiber optic cable being representative of the vibrations that propagate through, into, or around the cable. Based on the magnitude (e.g., amplitude), frequency, period, or the like, of the vibrations that are detected, the presence and/or location of one or more objects on the ground can be determined. For example, passage of a vehicle above the sensing cable can be detected, as well as the speed, direction of travel, size, or the like, of the vehicle. Optionally, changes in the vibrations can be used to identify damaged segments of a route being traveled upon by the vehicle. 
     In one aspect, the vibration monitoring systems and methods can detect vibrations caused by moving objects and determine information about the vibrations and/or objects based on the detected vibrations. This information that is determined can include peaks, waveforms, frequencies, amplitudes, or the like, in a frequency spectrum of the vibrations, or other information. This information can be used to identify the moving object, determine a location of the moving object, determine a speed of the object, identify a portion of a route being traveled on by the object that may be damaged, or the like. 
     The vibrations may change due to factors other than the moving objects (e.g., moving vehicles, damaged routes, or the like). For example, in different environmental conditions (e.g., different times, seasons, periods of condensation, etc.), the same object may cause the vibration monitoring systems and methods to detect different vibrations. The differences between the detected vibrations can be caused by the changing environmental conditions instead of the object of interest. The systems and methods can identify these differences caused by the environmental conditions and modify the information that is determined based on the detected vibrations to account for the changes caused by the environmental conditions. The systems and methods can therefore self-correct changes in the vibrations that are not caused by the objects of interest in order to improve the vitality, accuracy, precision, and functionality of the systems and methods. 
     Embodiments of the present invention may be used with a variety of vehicles, including rail vehicles, mining vehicles, OHVs, automobiles and the like. The vehicles may utilize internal combustion engines, electricity, a hybrid of the two, or other power sources. The vehicles may be automated, self-guided or may be guided via operator input. 
       FIG. 1  is a schematic diagram of a vibration monitoring system  100 , i.e. of a detecting system for detecting the presence of a vehicle on a railway track, according to one embodiment. The system  100  includes a control system  102  that generates baseline vibrations that are used to detect changing environmental conditions. The system  100  also includes a sensing system  104  that detects vibrations caused by objects of interest (e.g., vibrations of interest) and the baseline vibrations. Optionally, the system  100  may include multiple sensing systems  104  that separately detect the vibrations of interest or the baseline vibrations. 
     A sensing device  106  is disposed beneath a surface  108  of the ground (e.g., the surface of the earth or another surface). In one embodiment, the sensing device  106  is a fiber optic cable that communicates information between two or more locations by internally refracting light within the device  106 . Alternatively, the sensing device  106  may be another type of cable that can be used to detect vibrations in the ground. The sensing system  104  includes several sensors  110  (e.g., sensors  110 A-C) operably connected with the sensing device  106  at different locations. For example, the sensors  110  may be light-sensitive devices that measure changes in how light is internally reflected or otherwise refracted in the sensing device  106 . The number and arrangement of the sensors  110  is provided merely as one example. As described herein, the sensing device  106  can be used to sense vibrations propagating through the ground. Alternatively, another device, system, or apparatus may be used as the sensing device  106  to detect the vibrations. For example, one or more accelerometers, seismometers, or the like, may sense the vibrations. 
     A sensing processor  112  represents one or more computer processors (e.g., microprocessors) and advantageously an associated memory, hardware circuits or circuitry, or a combination thereof, that examine data that is output by the sensors  110  to measure the vibrations propagating through the sensing device  106 . For example, the sensors  110  may be conductively coupled with the sensing processor  112  by one or more wires, cables, or the like, and/or may be wirelessly connected with the sensing processor  112  such that the sensors  110  can communicate data representative of the vibrations detected using the sensing device  106  to the sensing processor  112 . 
     The sensing processor  112  examines the data received from the sensors  110  to identify the vibrations propagating through, into, and/or around the sensing device  106 . Based on these vibrations and/or changes in the vibrations, the sensing processor  112  can determine information about an object on the surface  108 . This information can include an identification of the object of interest on the surface  108 , a location of a moving object of interest on the surface  108 , a moving speed of the object of interest, a size of the object of interest, or the like. For example, different objects, different locations of the objects, different speeds of the objects, and/or different sizes of the objects may be associated with different patterns or waveforms of the vibrations that are determined by the sensing processor  112  and detected using the sensing device  106 . 
     In order to account for changes in environmental conditions and the impact of these changes in the vibrations caused by objects of interest, the control system  102  can generate baseline vibrations into the ground where the sensing device  106  is located. These baseline vibrations may be generated at pre-designated times and/or during pre-designated time periods. The baseline vibrations may be generated with pre-designated amplitudes and/or frequencies. As described below, these baseline vibrations may be detected by the sensing system  104  and used to modify and correct changes to vibrations of interest that are caused by environmental conditions. 
       FIG. 2  schematically illustrates the sensing system  104  of the vibration monitoring system  100  shown in  FIG. 1  during movement of an object of interest  200  according to one embodiment. The object of interest  200  is shown as a vehicle, such as a rail vehicle, automobile, mining vehicle, or the like, but alternatively may be another object. For example, the sensing device  106  can extend along a route, such as a railway track, for sensing vibrations generated by a vehicle, such as a rail vehicle, traveling along the route. During movement of the object of interest  200  on or near the surface  108 , vibrations of interest  202  are generated in the ground beneath the surface  108 . The vibrations of interest are vibrations that differ from baseline vibrations, as described herein. These vibrations of interest  202  propagate through the ground to the sensing device  106 . The vibrations of interest  202  can change the manner in which light is reflected within the sensing device  106 . These changes are detected by the sensors  110  as changes in intensities of light, changes in intensities of light at different wavelengths, or the like. The sensors  110  output data representative of the light and/or changes in the manner in which the light is reflected within the sensing device  106 . This data is communicated to the sensing processor  112 . 
       FIG. 3  illustrates one example of a frequency spectrum of vibrations of interest  300  generated by movement of the object of interest  200  shown in  FIG. 2  as detected by the sensing system  104 . The vibrations of interest  300  are shown alongside a horizontal axis  302  representative of frequencies of the vibrations of interest  300  and a vertical axis  304  representative of amplitude or magnitude of the vibrations of interest  300  at the different frequencies. 
     The vibrations of interest  300  can represent the vibrations detected by the sensing system  104  during movement of the object of interest  200 . These vibrations of interest  300  can represent a signature or waveform that is associated with the object of interest  200 . When the vibrations of interest  300  are detected, the object of interest  200  can be identified by the sensing processor  112  by comparing the vibrations of interest  300  to different signatures or waveforms that are associated with different objects of interest  200 , and identifying the object of interest  200  based on this comparison. For example, the signatures or waveforms may be defined as designated peaks in the vibrations of interest  300  that are located at designated frequencies and/or within a designated range of frequencies. If the vibrations of interest  300  have peaks in the designated frequencies and/or designated range of frequencies, then the vibrations of interest  300  may be identified as the object of interest  200  that is associated with the designated frequencies and/or designated range of frequencies of the signature or waveform. Optionally, different objects of interest  200  may be associated with different signatures or waveforms, different speeds of different objects of interest  200  may be associated with different signatures or waveforms, different locations of objects of interest  200  may be associated with different signatures or waveforms, and the like, so that the sensing system  104  may be able to identify different objects of interest  200 , different speeds of objects of interest  200 , different locations of the objects of interest  200 , and the like. 
     The sensing processor  112  may not be able to identify the object of interest  200  due to changes in environmental conditions, however. For example, the density, makeup, mass, or the like, of the ground may change at different times of the day, during different seasons, and during different weather conditions (e.g., rain, snow, ice, dry weather, etc.). These different environmental conditions can impact the manner in which the vibrations of interest  202  (shown in  FIG. 2 ) propagate through the ground and are detected by the sensing system  104 . 
     For example, during first environmental conditions (e.g., dry weather during daylight of a summer month), the vibrations of interest may appear as the vibrations of interest  300  shown in  FIG. 3 . But, during different, second environmental conditions (e.g., wet weather during the night of a spring month), the same object of interest  200  may generate the vibrations of interest that are detected by the sensing system  104  as vibrations of interest  306  in  FIG. 3 . During different, third environmental conditions (e.g., ice on the ground during the winter), the same object of interest  200  may generate the vibrations of interest that are detected by the sensing system  104  as vibrations of interest  308  in  FIG. 3 . The changing environmental conditions can prevent the sensing system  104  from being able to accurately identify the object of interest  200  based on the vibrations that are detected. 
     Returning to the description of the vibration monitoring system  100  shown in  FIG. 1 , the system  100  can adapt to changes in the environmental conditions by repeatedly monitoring changes in baseline vibrations generated by the system  100  and using these changes to modify (e.g., correct) the information that is determined from the vibrations of interest generated by the objects  200  (shown in  FIG. 2 ). The control system  102  may generate baseline vibrations  114  in the ground by moving a weighted object  116  relative to the ground. The weighted object  116  can be a weight, a body with a moveable eccentric mass, or another type of body that can generate vibrations in the ground when moved relative to the ground. The weighted object  116  shown in  FIG. 1  can be moved toward the surface  108  of the ground to strike the ground and generate the baseline vibrations  114 . The weighted object  116  can then be moved away from the ground for preparation in striking the ground again to generate additional baseline vibrations  114 . 
     The control system  102  includes a controller  118  that represents one or more computer processors (e.g., microprocessors), hardware circuits or circuitry, or a combination thereof. The controller  118  controls generation of the baseline vibrations  114  by controlling movement of the object  116 . An actuator  120  moves the object  116  pursuant to instruction signals received from the controller  116 . The actuator  120  can include a motor, electromagnet, pneumatically controlled piston, or another device capable of moving the object  116  to generate the baseline vibrations  114 . The controller  118  generates the instruction signals and communicates the signals to the actuator  120  via one or more wired and/or wireless connections. The signals can indicate the times at which the actuator  120  is to move the object  116  to generate the baseline vibrations  114 , how long of a time period that the actuator  120  is to generate the baseline vibrations  114 , and/or how to move the object  116  to generate the baseline vibrations  114 . With respect to instructions on how to move the object  116 , these instructions can tell the actuator  120  how high to lift the object  116  off the surface  108  before dropping or moving the object  116  toward the surface  108 , how quickly to move the object  116  toward the surface  108  (or whether to drop the object  116  onto the surface  108 ), how many times to move the object  116 , and/or how frequently the object  116  should be moved. If the object  116  is to be dropped onto or otherwise moved into contact with the surface  108  or another object in contact with the surface  108  to generate the baseline vibrations  114 , then the instructions can dictate how fast the object  116  is moved toward the surface  108  or other object, how far the object  116  is away from the surface  108  when the object  116  is dropped or moved toward the surface  108 , and the like. If the object  116  is moved relative to the surface  108  without striking the surface  108  or an object on the surface  108  (e.g., the object  116  is an eccentric mass that is rotated or otherwise moved relative to the surface  108  to generate the baseline vibrations  114 ), then the instructions can dictate how rapidly the object  116  is moved, how long the object  116  is moved, or the like. 
       FIG. 4  illustrates a frequency spectrum of baseline vibrations  400 ,  402 ,  404  generated by the control system  102  shown in  FIG. 1  during different environmental conditions according to one embodiment. The baseline vibrations  400 ,  402 ,  404  are shown alongside the horizontal and vertical axes  302 ,  304  described above in connection with  FIG. 3 . The baseline vibrations  400 ,  402 ,  404  are generated by the control system  102  by moving the same object  116  (shown in  FIG. 1 ) in the same manner, but at different times and under different environmental conditions. For example, the baseline vibrations  400  may be sensed by the sensing system  104  responsive to a ten pound (or 4.5 kilogram) object  116  being dropped onto the surface  108  (shown in  FIG. 1 ) from one foot (or thirty centimeters) above the surface  108  during dry conditions during the daytime. The baseline vibrations  402 ,  404  may be generated and sensed during other conditions. For example, the baseline vibrations  402  may be generated by dropping the same ten pound (or 4.5 kilogram) object  116  being onto the surface  108  from one foot (or thirty centimeters) above the surface  108  during rain, when there is snow on the surface  108 , during nighttime, or the like. The baseline vibrations  404  may be generated by dropping the same ten pound (or 4.5 kilogram) object  116  being onto the surface  108  from one foot (or thirty centimeters) above the surface  108  when there is ice on the surface  108 . 
     The control system  102  can generate the baseline vibrations at designated times, such as times that are known to the sensing system  104 . The control system  102  can generate the baseline vibrations at times that are known or communicated to the sensing system  104  (e.g., by the controller  118  of the control system  102  or another device) so that the sensing system  104  can differentiate between baseline vibrations and vibrations of interest. 
     In one aspect, the sensing processor  112  can determine that the system  100  is malfunctioning based at least in part on the baseline vibrations. For example, the sensing processor  112  may be aware of the times at which the baseline vibrations are generated by the control system  102 . If the sensing processor  112  does not detect the baseline vibrations at times that correspond to when the baseline vibrations are generated, then the sensing processor  112  can determine that the system  100  is malfunctioning. Responsive to determining this, the sensing processor  112  can communicate one or more warning signals to another location, such as a repair facility, dispatch facility, or the like, to warn of the malfunction of the system  100 , and/or to request inspection, repair, maintenance, or the like, of the system  100 . 
     The baseline vibrations  400  can be designated as a calibration signature. The sensing system  104  may periodically, regularly, randomly, or otherwise repeatedly re-determine the baseline vibrations that are used as the calibration signature. Subsequently obtained baseline vibrations  402 ,  404  can be compared to the calibration signature in order to determine how the vibrations sensed by the sensing system  104  change, due to the changing environmental conditions. For example, the sensing system  104  can sense the baseline vibrations  402  and compare the baseline vibrations  402  to the baseline vibrations  400  by comparing characteristics of the vibrations  400 ,  402  with each other. These characteristics can include, but are not limited to, locations (e.g., frequencies) of peaks  406  (e.g., peaks  406 A-H), widths of the peaks  406  (e.g., the ranges of frequencies over which one or more peaks  406  extend, heights of peaks  406  (e.g., the amplitude of one or more of the peaks  406  along the vertical axis  304 ), and the like. 
     In the illustrated example, the sensing system  104  can compare the baseline vibrations  400 ,  402  and determine that the peak  406 B in the baseline vibration  400  has moved to a lower frequency and/or has a reduced amplitude as the peak  406 A in the baseline vibration  402 , that the peak  406 E in the baseline vibration  400  has moved to a lower frequency and/or has a reduced amplitude as the peak  406 D in the baseline vibration  402 , and/or that the peak  406 F in the baseline vibration  400  has the same or similar frequency as the peak  406 G (e.g., is within a designated range of the peak  406 F, such as 1%, 5%, 10%, or the like) and/or has a reduced amplitude as the peak  406 G in the baseline vibration  402 . 
     The sensing system  104  can use these differences between the baseline vibrations  400 ,  402  to correct the information about the objects  200  that is determined from the vibrations of interest  300 ,  306 ,  308  shown in  FIG. 3 . For example, due to changing environmental conditions, the baseline vibrations  400 ,  402  appear to shift to lower frequencies and/or have reduced amplitudes, as described above. To correct for the impact of the changing environmental conditions on the vibrations of interest, the sensing system  104  can measure frequencies and/or amplitudes from the vibrations of interest, and then modify these frequencies and/or amplitudes. For example, the sensing system  104  can increase the value of the measured frequencies at which peaks appear in the vibrations of interest  300 ,  306 ,  308 , can increase the value of the amplitudes of the peaks in the vibrations of interest  300 ,  306 ,  308 , or the like. The frequencies and/or amplitudes of the peaks in the vibrations of interest  300 ,  306 ,  308  can be increased by the same amount that the frequencies and/or amplitudes of the peaks in the baseline vibrations  400 ,  402  decreased, or may be increased by an amount that is at least partially based on the decrease in the peaks in the baseline vibrations  400 ,  402 . While the sensing system  104  may not be actually changing the frequencies, amplitudes, or the like, of the peaks, the sensing system  104  can change the measured frequencies, amplitudes, or the like, that are measured from the vibrations of interest and used to identify information about the object  200 . 
     As another example, the sensing system  104  can compare the baseline vibrations  400 ,  404  and determine that the peak  406 B in the baseline vibration  400  has moved to a higher frequency and/or has a reduced amplitude as the peak  406 C in the baseline vibration  404 , and/or that the peak  406 F in the baseline vibration  400  has moved to a higher frequency and/or has an increased amplitude as the peak  406 H in the baseline vibration  404 . The sensing system  104  can use these differences between the baseline vibrations  400 ,  404  to correct information determined from the vibrations of interest  300 ,  306 ,  308  shown in  FIG. 3 . For example, due to changing environmental conditions, the baseline vibrations  400 ,  402  appear to shift to higher frequencies and/or have increased amplitudes, as described above. To correct for the impact of the changing environmental conditions on the vibrations of interest, the sensing system  104  can modify the frequencies and/or amplitudes that are measured from the vibrations of interest. For example, the sensing system  104  can decrease the frequencies at which peaks appear in the vibrations of interest  300 ,  306 ,  308 , can decrease the amplitudes of the peaks in the vibrations of interest  300 ,  306 ,  308 , or the like. The frequencies and/or amplitudes of the peaks in the vibrations of interest  300 ,  306 ,  308  can be decreased by the same amount that the frequencies and/or amplitudes of the peaks in the baseline vibrations  400 ,  404  increased, or may be decreased by an amount that is at least partially based on the increase in the peaks in the baseline vibrations  400 ,  404 . 
     In one embodiment, the sensing system  104  can determine information about the environmental conditions based on the differences between the baseline vibrations. For example, based on decreases in frequency for one or more peaks in the baseline vibrations, the sensing system  104  can determine that the ground is becoming softer, such as due to rainfall. Alternatively, based on increases in frequency for one or more peaks in the baseline vibrations, the sensing system  104  can determine that the ground is becoming harder, such as due to ice forming on and/or in the ground. The sensing system  104  can use this information about the environmental conditions to change vibrations of interest, as described above. Additionally or alternatively, the sensing system  104  can use the information about the environmental conditions to warn operators of vehicles of dangerous conditions. For example, the sensing system  104  can generate signals that are communicated to vehicles to warn the vehicles of potential ice, rain, or the like, that the sensing system  104  may have detected. 
     Once the information determined from the vibrations of interest is corrected, the vibrations of interest can be referred to as corrected or modified vibrations of interest. For example, a waveform, measured frequency of a peak, measured amplitude of a peak, or the like, in the vibration of interest may be corrected by changing the measured waveform, measured frequency, and/or measured amplitude to a modified waveform, frequency and/or amplitude. This corrected or modified information can be compared to the signatures or waveforms associated with different objects of interest. Depending on which signatures or waveforms more closely match or otherwise correspond to the corrected or modified information, the sensing system  104  may be able to identify the object of interest, the speed of the object of interest, the location of the object of interest, the size of the object of interest, or the like, based at least in part on the corrected or modified information. The identified object, speed, location, size, or the like can be used for a variety of purposes, such as to activate a warning system or signal that a vehicle is approaching, to determine if a vehicle is traveling too fast or too slow, to generate control signals that automatically slow down or speed up the vehicle based on the speed that is determined, or the like. For example, based on the corrected information, the sensing system  104  can determine a size of a moving vehicle, the location of the vehicle, and/or how fast the vehicle is moving. The size of the vehicle may be used by the sensing system  104  to differentiate between different vehicles and thereby identify the vehicle. Based on the location of the vehicle and the speed of the vehicle, the sensing system  104  can generate control signals that are communicated to one or more locations, such as a dispatch center, where the identify, location, and/or speed of the vehicle can be displayed to one or more operators to monitor movements of the vehicle. Optionally, these control signals may be communicated to a signal (e.g., a light or a gate) to actuate the signal and warn other vehicles of the movement of the detected vehicle. 
       FIG. 5  illustrates a flowchart of a method  500  for monitoring vibrations according to one embodiment. The method  500  can be performed by the monitoring system  100  shown in  FIG. 1  and described above. At  502 , vibrations are sensed. For example, vibrations propagating through the ground may be detected. The vibrations can be sensed by examining changes in light being conveyed through a cable, such as a fiber optic cable. Alternatively, the vibrations may be sensed in another manner, such as by using one or more accelerometers or other devices. At  504 , a determination is made as to whether the sensed vibrations are baseline vibrations. The baseline vibrations may be generated at known or designated times, or within known or designated time periods. If the vibrations are sensed at the known or designated times, within a designated time period following the known or designated times (e.g., within thirty seconds or another time period), within the known or designated time periods, or the like, then the sensed vibrations may be identified as baseline vibrations. As a result, flow of the method  500  can proceed to  506 . On the other hand, if the sensed vibrations are not sensed at times that would correspond with the generation of the baseline vibrations, then flow of the method  500  can proceed to  512 , which is described below. 
     At  506 , the baseline vibrations are examined for changes from one or more previous baseline vibrations. For example, the baseline vibrations sensed at  502  can be compared with previously sensed baseline vibrations to determine if shapes, waveforms, peaks, or the like, in the previously sensed baseline vibrations have moved (e.g., changed which frequencies the peaks appear at), changed shape (e.g., have larger or smaller amplitudes, are wider or narrower, etc.), or otherwise changed. 
     At  508 , a determination is made as to whether the baseline vibrations have changed. If the baseline vibrations have changed from one or more previously sensed baseline vibrations, then environmental conditions may be altering the propagation of vibrations through the ground. As a result, the vibrations generated by objects of interest also may be altered by the environmental conditions in a similar manner. If the baseline vibrations have changed or have changed by at least a significant amount (e.g., the frequency of a peak changes by at least a designated, non-zero amount, such as 1%, 5%, 10%, or another amount), then flow of the method  500  can proceed to  510 . On the other hand, if the baseline vibrations have not changed, or have not changed by a significant amount, then flow of the method  500  can proceed to  512 , which is described below. 
     At  510 , corrections to sensed vibrations are determined from the changes in the baseline vibrations. For example, the change in the frequencies at which one or more peaks appear in the baseline vibrations, the change in amplitudes of the peaks, or other changes, may be calculated. At  512 , vibrations of interest are sensed. If the vibrations sensed at  504  are not baseline vibrations, then the sensing of vibrations at  504  and  512  may be the same operation of sensing the same vibrations. Because the vibrations are not baseline vibrations used to determine corrections to account for changing environmental conditions, the vibrations may be vibrations of interest. These vibrations may be used to identify an object of interest, speed of the object of interest, a location of the object of interest, or the like. 
     At  514 , the vibrations of interest are corrected based on the corrections determined from the baseline vibrations. For example, one or more frequencies, amplitudes, waveforms, or the like, that are determined from the vibrations of interest can be modified based on the corrections determined from the baseline vibrations. If no corrections were determined based on changes in the baseline vibrations (e.g., the baseline vibrations were not affected by the environmental conditions or were not significantly affected such that one or more peaks did not shift frequencies and/or change amplitudes by at least a designated, non-zero amount), then the information obtained from the vibrations of interest may not be modified. On the other hand, if corrections were determined based on changes in the baseline vibrations, then these corrections may be applied to the information determined from the vibrations of interest to form corrected or modified information from the vibrations of interest. 
     At  516 , the corrected vibrations of interest (or vibrations of interest that were not corrected due to the lack of significant changes to the baseline vibrations) are compared to one or more designated signatures or waveforms. As described above, different signatures or waveforms may include different patterns, arrangements, or the like, of peaks, and may be representative of different types of objects of interest, different moving speeds of different objects of interest, different locations of objects of interest, etc. 
     At  518 , a determination is made as to whether the corrected vibrations of interest (or vibrations of interest that were not corrected due to the lack of significant changes to the baseline vibrations) match one or more of the signatures or waveforms. For example, a determination may be made as to whether the peaks or other shapes of the frequency spectrum of the corrected vibrations of interest more closely match the peaks or other shapes of a signature or waveform than one or more other signatures or waveforms. If so, then flow of the method  500  can proceed to  520 . For example, the corrected vibrations of interest may closely match the peaks of a signature or waveform representative of a particular object of interest, a particular speed of an object of interest, a particular location of an object of interest, or the like. On the other hand, if the corrected vibrations of interest do not match one or more of the signatures or waveforms, then the vibrations of interest may not represent an object of interest, a speed of an object of interest, a location of an object of interest, or the like. As a result, flow of the method  500  can return to  502  for additional vibrations to be sensed. 
     At  520 , information about an object of interest is determined based at least in part on the vibrations of interest. For example, the object of interest, the location of the object of interest, the speed of the object of interest, or the like, that is associated with a signature or waveform that more closely matches the corrected vibrations of interest than other signatures or waveforms may be identified. After this identification, flow of the method  500  can return to  502  so that additional vibrations can be sensed, corrected, and/or used to identify information about an object of interest. 
     Returning to the description of the vibration monitoring system  100  shown in  FIG. 1 , the system  100  can adapt to changes in the location of the sensing device  106  and/or other components of the sensing system  104  by continuously and repeatedly verifying integrity of the sensing device signals. Accordingly, in another aspect, the system  100  may also include a calibration device  122  that is placed in the vicinity of the sensing device  106  and which can be utilized by the system  100  as a vital way to ensure that movements in either the calibration device  122  or the sensing device  106  and/or other components of the sensing system  104  are detected and accounted for. The calibration device  122  may interface with a wayside bungalow  124  containing communication equipment that relays health information of the calibration device  122  to the sensing processor  112 . While the calibration device  122  and wayside bungalow  124  are illustrated as being separate from control system  102 , in an embodiment, the calibration device  122  and wayside bungalow  124 , including the communication equipment contained therein, may be integrated with the control system  102 . By integrating the calibration device and communication equipment with the control system  102 , duplication of components performing related functions may be obviated. 
     In one embodiment, the calibration device  122  includes an acoustic device configured to generate and amplify an analog tone  126  that propagates, through air and/or sub-terrain, to the sensing device  106 , and is utilized as a regular calibration or reference point, as discussed hereinafter. The acoustic device may be, for example, a low frequency acoustic transducer that is configured to impart a low frequency acoustic signal (e.g., 1 to 30 Hz) to ground or otherwise. Alternatively or additionally, the acoustic device may utilize so-called ground penetrating sonar, such as described in U.S. Pat. No. 5,719,823, issued Feb. 17, 1998 and incorporated by reference herein in its entirety. Part of the acoustic device may be buried in the ground surface to facilitate transmission of acoustic energy from the device to soil. Additionally, soil around the buried portion may be made uniform or otherwise augmented to facilitate transfer of acoustic energy from the buried portion to non-augmented soil in which the fiber optic cable is buried. 
     The calibration device  122  may be installed on a moving platform or fixed anywhere along the wayside route and provides a reference point or location point through either a mile post marking, survey marker, GPS, or other known reference point. The exact location of the calibration device  122  is stored by the sensing processor  112  as a repeatable reference point and verified as needed for system integrity checking. Once calibrated, a window threshold may be set and, when exceeded, the system  100  will be alerted that the sensing device  106  has moved or the calibration device  122  has moved or is being interfered with. In an embodiment, the calibration device  122  may send a continuous signal to the sensing device  106 . In other embodiments, the calibration device  122  may output the reference tone  126  at defined intervals. 
     In particular, in one embodiment, the calibration device  122  may have an on-board, real-time precision clock  128 . Embedded software/firmware utilizes the on-board clock  128  to energize the acoustic output at defined intervals. The device  122  has communication abilities, which allow for the syncing of the device  122  with a wayside location or to the back office to ensure drift of the clock  128  is accommodated. 
     In another embodiment, the calibration device  122  receives communication protocol at regular intervals in the event that the system  100  needs to verify the accuracy and location of the device  122 . The calibration device  122  will then generate the analog signal, and report back to the sensor processor  112  once it has generated the signal. The sensor processor  112  will then confirm that a signal was received both from the sensors  110  as well as the status from the calibration device  122  to confirm the output was successfully energized. 
     In the event that the sensing device  106  is moved, and to prevent a false positive signal from the calibration device  122  to the sensing device  106 , the calibration device  122  is provided as a constant power output device that monitors the output signal  126  and ensures that a failure mode of the device does not falsely output an increase in energy or signal level such that the sensing device  106  will detect the reference signal from a greater distance away. 
     The calibration device  122  may be arranged within a housing (not shown) capable of withstanding the harsh environment of an external wayside (e.g., rail) location. In certain embodiments, the calibration device  122  accepts either standard DC or AC input to energize the device using common connector types such as Wago or Phoenix, and has the ability to communicate either fiber optically or over Ethernet back to a wayside bungalow  126  or back office to report the status of the device  122  as a form of health indication and monitoring. 
       FIG. 6  illustrates a flowchart of a method  600  for verifying the integrity of the sensing system  104 . The method  600  can be performed by the monitoring system  100  shown in  FIG. 1  and described above. At  602 , the sensing processor  112  continuously monitors the sensing device  106  for signals, in the manner described above, to determine vehicle movement or for calibration information generated by the calibration device  122 . At step  604 , the calibration device outputs an analog signal to be received by the sensing device  106  at a given location. At step  606 , the sensing processor  112  receives the signal generated by the calibration device  122  through the sensing device  106 . The sensing processor  112 , at step  608 , then verifies that the signal level of the received signal is within a predetermined threshold, which signifies that the calibration device  122  and the sensing device  106  have not moved. 
       FIG. 7  illustrates a flowchart of a method  700  for determining the location status of the calibration device  122 . The method  700  can be performed by the monitoring system  100  shown in  FIG. 1  and described above. At step  702 , the calibration device  122  may utilize GPS or other time-based location to determine status. Mile post may also be programmed into the calibration device  122 . At step  704 , the calibration device  122  syncs with the sensing processor  112  or wayside equipment to confirm date, time and location. At step  706 , the acoustic signal sent through the sensing device  106  is utilized to verify that the sensing device (i.e., the fiber optic cable) has not moved and the calibration device  122  has not moved. If the sync does not occur or the sensing processor  112  determines that the signal level is unacceptable (e.g., outside of a predefined threshold window), the sensing processor  112  will alert the system  100 , at step  708 , that the calibration device  122  cannot be trusted. 
     As discussed above, to ensure the safety integrity level is maintained and the calibration device  122  has not been relocated, the calibration device  122  includes a form of self-location, such as GPS or other time-based synchronization system similar to that contained in aircraft navigation systems. This self-location information may be communicated either to the fiber interrogation equipment (i.e., the sensing processor  112 ) or stored in the sensing processor  112  which will validate the reported position versus the allowable position. This will provide notification in the instance that the calibration device  122  has been moved to maintain vitality of the system  100 . 
     In one embodiment, a system includes an acoustic device that outputs an analog signal to a fiber cable for calibration and location verification. The acoustic device utilizes GPS or communication from wayside bungalow equipment to verify GPS location or real-time clock information. The wayside bungalow contains communication equipment that interfaces with the acoustic device and relays health information to a sensing processor. The sensing processor is configured to detect the acoustic signal output by the acoustic device at a known location and verifies that the cable and device have not moved location by comparing the signal level received against a threshold stored in memory. When the threshold is exceeded, the sensing processor sends an alert that the fiber optic cable or acoustic device at the location have changed. 
       FIG. 8  is a schematic diagram of a vibration monitoring system  800 , i.e. of a detecting system for detecting the presence of a vehicle on a railway track, according to one embodiment. The detecting system  800  includes a control system  802  configured for generating and emitting signals into the ground  808 . The signals correspond for example to vibrations produced into the ground and/or to analog tones. The signals correspond notably to baseline vibrations that are used to detect changes in environmental conditions and/or initialization vibrations that are used to initialize a sensing system  804  of the detecting system, and/or analog tones that propagate, through air and/or sub-terrain, to the sensing system  804  and are utilized as a regular calibration or reference point. 
     The sensing system  804  is adapted for detecting vibration into ground and notably for detecting vehicles circulating on the track inducing second signals, i.e. vibrations of interest, also called second signals. 
     The sensing system  804  is also adapted for detecting first, third and fourth signals corresponding respectively to initialization vibrations V 1  that are used to initialize the sensing system  804 , analog tones used to detect if the control system or the sensing system has moved in an unexpected manner, baseline vibrations V 2  that are used to detect changes in environmental conditions. 
     The sensing system  804  comprises a sensing device  806  and sensors  810  ( 810 A,  810 B,  810 C) comprising respectively the same elements, arranged in a same manner, than the sensing system  104  and the sensing device  106 , described above in the first embodiment described. 
     The sensing system  804  is associated with a sensing processor  812 , also called sensing module, monitoring the sensing system  804 , the sensing processor comprising the same elements, arranged in a same manner, than the sensing processor  112 , described above in the first embodiment described. 
     The control system  802  comprises a controller  822  that represents one or more computer processors (e.g., microprocessors), hardware circuits or circuitry, or a combination thereof, which is associated with a central memory  824 . 
     Advantageously the controller  822  is adapted for executing software programming instructions comprised in the central memory  824 . 
     The control system  802  comprises a moving object  830  adapted for generating vibrations into the ground and notably baseline vibrations V 2  that are used to detect changes in environmental conditions of the track and initialization vibrations V 1  that are used to initialize the sensing processor  812 . 
     The control system  802  comprises an actuator  832  configured for controlling the movement of the moving object  830 . Advantageously, the actuator comprises two functioning mode a track configuration mode in which it commands the moving object to emit the first signal corresponding to the initialization vibrations V 1  and a supervision mode in which it commands the moving object to emit the fourth signal corresponding to the baseline vibrations V 2 . 
     The control system  802  comprises also a communication device  836  adapted for communicating data and notably exchanging messages with the sensing processor  812  and a calibration device  838  corresponding to the calibration device  122  described above. The calibration device  838  is adapted for sending the third signal corresponding to an analog tone T 1  that propagates, through air and/or sub-terrain, to the sensing system  804  and is utilized as a regular calibration or reference point. 
     Advantageously the control system  802  comprises a localization device  839 , such as a GPS device, adapted for determining the position of the control system  802 . 
     The control system  802  is preferably movable and mounted on wheels, in order that an operator can move the control system  802  along the railway track. 
     Advantageously the control system  802  is adapted to be taken off the wheels and installed along the track close to a sensing system  804  after the initialization of the sensing processor  812 . 
     The sensing processor  812  comprises a detection module  840  for detecting a vehicle on the railway track, a configuration device  842  adapted for configuring the detection module  840 , a security module  844  to determine if at least one of the calibration device  838  or the sensing device  806  has moved and a control module  846  adapted for supervising changes in the environmental conditions of the sensing system  804 . 
     The central memory  824  comprises initialization programming instructions  850  and controlling programming instructions  856 . 
     The initialization programming instructions  850  and the controller  822  form with the moving object  830 , the actuator  832  and the communication device  836  an initialization device. 
     The initialization programming instructions  850  are configured, while they are executed, to command the actuator  832 , to emit the first signal into the ground  808  towards the sensing processor  812  through the sensing device  806 , which is for example a fiber optic cable. 
     The initialization programming instructions  850  are also configured, while they are executed, to generate a first message comprising configuration data chosen among, location of the initialization device, intensity/magnitude of the first signal, emission time of the first signal and type of objects corresponding to the first signal, and to command the sending of the first message to the sensing processor  812  through the communication device  836 . 
     Advantageously, the configuration data comprise at least the first signal intensity/magnitude. 
     Preferentially, the initialization programming instructions  850  are configured for commanding the emission of the first signal and the sending of the first message approximately simultaneously. 
     Advantageously, the controller  822  is adapted for executing the initialization programming instructions  850  several times for a given location of the control system  802 , in order to successively emit different first signals having different intensity levels. The initialization programming instructions  850  are for example executed at predetermined time intervals, or each time an activator on the control system is activated, or when the initialization device is not moving for a predetermined amount of time. 
     The fact that the control system  802  can send the first signal at times that are known to the sensing system  804  and notably communicated to the sensing system  804  allows to differentiate first signals from other signals. 
     The controlling programming instructions  856  are configured, while they are executed, to command the actuator  832 , to send the fourth signal into the ground towards the sensing processor  812  through the sensing device  806  which is for example a fiber optic cable. 
     The controlling programming instructions  856  are also configured, while they are executed, to generate a second message comprising control data chosen among, location of the control system  802 , intensity/magnitude of the fourth signal, emission time of the fourth signal, and to command the sending of the second message to the sensing processor  812  through the communication device  836 . 
     Preferentially, the controlling programming instructions  856  are configured for commanding the emission of the fourth signal and the sending of the second message approximately simultaneously. 
     Advantageously, the fourth signal is outputted at predetermined times and/or during predetermined time periods, the fourth signal having advantageously a predetermined amplitude, i.e. intensity/magnitude, and/or frequency. 
     The fact that the control system  802  can send the fourth signal at times that are known to the sensing system  804  and notably communicated to the sensing system  804  and with specific amplitude and/or frequency allows to differentiate fourth signals from other signals. 
     The calibration device  838  is configured for outputting the third signal towards the sensing processor  812  through the sensing device  806 . 
     Advantageously the intensity/magnitude of the third signal is predetermined for a given location of the control system and the sensing processor. 
     The calibration device  838  includes an acoustic device  860  configured to generate and amplify the analog tone that propagates, through air and/or sub-terrain, to the sensing device, and is utilized as a regular calibration or reference point, as discussed hereinafter. The acoustic device may be, for example, a low frequency acoustic transducer that is configured to impart a low frequency acoustic signal (e.g., 1 to 30 Hz) to ground or otherwise. Alternatively or additionally, the acoustic device may utilize so-called ground penetrating sonar, such as described in U.S. Pat. No. 5,719,823, issued Feb. 17, 1998 and incorporated by reference herein in its entirety. Part of the acoustic device may be buried in the ground surface to facilitate transmission of acoustic energy from the device to soil. Additionally, soil around the buried portion may be made uniform or otherwise augmented to facilitate transfer of acoustic energy from the buried portion to non-augmented soil in which the fiber optic cable is buried. 
     The calibration device  838  is adapted for providing a reference point or location point to the sensing processor thanks to the localization device  839  and the communication device  836 . The exact location of the calibration device is stored by the sensing processor as a repeatable reference point and verified as needed for system integrity checking. For example, the calibration device  838  is adapted for sending to the sensing processor  812  the position of the control system  802  determined by the localization device  839 . Once calibrated, a window threshold may be set in the sensing processor  812  and, when intensity/magnitude level of the third signal exceeded, the security module  844  is adapted to determine that the sensing device has moved or the calibration device has moved or is being interfered with. The window threshold may depend on the control system position sent by the control system  802 . In an embodiment, the calibration device  838  may send the third signal continuously to the sensing device  806 . In other embodiments, the calibration device  838  may output the third signal, i.e. the reference tone at defined intervals and approximately at the same time send the location of the control system  802  to the sensing processor  812 . 
     Advantageously, the frequency of the third signal is not comprised in the frequency spectrum of the first and fourth signals so that the sensing processor  812  can differentiate the three signals. 
     More advantageously, the first, third and fourth signals are emitted at times that are known or communicated to the sensing processor  812  (e.g., by the control system  802 ) and with predefined frequency spectrum and intensity/magnitude intervals so that the sensing processor  812  can differentiate between first, third, fourth signals and second signals, corresponding to a second signal induced by a vehicle moving on the track close to the sensing system  804 . 
     The configuration device  842  is adapted for configuring the detection module  840  in function of the received first signal and the received configuration data. 
     The configuration device  842  is notably adapted for memorizing in a comparison unit  870  of the detection module  840  a set of measured data relative to the received first signal and to associate to the memorized set of measured data the received configuration data. 
     Advantageously when the configuration device  842  received several first signals having the same intensity and sent from the same location it determines the set of measured data to memorize in function of the different first signals received, by performing for example an averaging algorithm. 
     Advantageously in the comparison unit  870 , the memorized set of measured data is associated with a type of detected object, according to the signal intensity comprised in the associated configuration data and preferentially is associated also with a location of the type of detected object determined in function of the location of the initialization device comprised in the configuration data. 
     The comparison unit  870  memorizes, for example, a set of measured data for each first signal received having a different value of signal intensity comprised in the associated configuration data and/or a different location comprised in the associated configuration data. 
     The sensing processor  812  and notably the comparison unit  870  is configured for comparing a received second signal, generated by an object moving near the sensing processor, with each memorized set of measured data in order to determine a type of detected object circulating on the railway track and preferentially also its location. 
     More advantageously, the memorized set of measured data is relative to a general form of the first signal monitored by the sensing processor  812  through the sensing device  806  and corresponds to a signal signature or waveform which is associated with a type of detected object, notably in function of the signal intensity/magnitude comprised in the associated configuration data. The signatures or waveforms may be defined as designated peaks that are located at designated frequencies and/or within a designated range of frequencies. If the vibrations of interest, i.e. the second signals, have peaks in the designated frequencies and/or designated range of frequencies, then the vibrations of interest may be identified as the object of interest that is associated with the designated frequencies and/or designated range of frequencies of the set of measured data. Optionally, different objects of interest may be associated with different set of measured data, different speeds of different objects of interest may be associated with different set of measured data, different locations of objects of interest may be associated with different set of measured data, and the like, so that the sensing system  804  and notably the detection module  840  may be able to identify different objects of interest, different speeds of objects of interest, different locations of the objects of interest, and the like comparing second signals with memorized sets of measured data. 
     Depending on which set of measured data, i.e. signatures or waveforms more closely match or otherwise correspond to the received second signal, the sensing processor  812  may be able to identify the object of interest, the speed of the object of interest, the location of the object of interest, the size of the object of interest, or the like. 
     The security module  844  is adapted for comparing the third signal amplitude with a window threshold to determine if at least one of the calibration device or the sensing device  806  has moved. When intensity level of the third signal exceeds the window threshold, the security module  844  is adapted to determine that the sensing device has moved or the calibration device has moved or is being interfered with. 
     The calibration device  838  and the security module are, for example, adapted for implementing the method  700 . 
     The control module  846  is adapted for supervising changes in the environmental conditions of the sensing system  804 . The control module  846  is notably configured for comparing the received fourth signal with pre-memorized data in order to detect changing in environmental conditions of the railway track. 
     The control module  846  is adapted for amending the memorized set of measured data or data relative to a received second signal in function of the detected changes in environmental conditions of the railway track. The control module  846  is adapted to obtain information about environmental conditions and detect changes as described for the sensing processor  112  above. The baseline vibrations  400  can be for example designated as a calibration signature. The sensing processor  812  may periodically, regularly, randomly, or otherwise repeatedly re-determine the baseline vibrations that are used as the calibration signature. Subsequently obtained baseline vibrations  402 ,  404  through sensing device  806  can be compared to the calibration signature in order to determine how the vibrations sensed by the sensing system  804  change due to the changing environmental conditions. For example, the control module  846  can sense the baseline vibrations  402  and compare the baseline vibrations  402  to the baseline vibrations  400  by comparing characteristics of the vibrations  400 ,  402  with each other. These characteristics can include, but are not limited to, locations (e.g., frequencies) of peaks  406  (e.g., peaks  406 A-H), widths of the peaks  406  (e.g., the ranges of frequencies over which one or more peaks  406  extend, heights of peaks  406  (e.g., the amplitude of one or more of the peaks  406  along the vertical axis  304 ), and the like. 
     In one embodiment, the control module  846  is adapted for amending a received second signal, induced by a vehicle moving on the track close to the sensing system  804 , in function of the detected changes in environmental conditions of the railway track. 
     The control module  846  can use differences between the baseline vibrations  400 ,  402  to correct data relative to received second signals, that are determined from the vibrations of interest  300 ,  306 ,  308  shown in  FIG. 3 . For example, due to changing environmental conditions, the baseline vibrations  400 ,  402  appear to shift to lower frequencies and/or have reduced amplitudes, as described above. To correct for the impact of the changing environmental conditions on the vibrations of interest, the control module  846  can measure frequencies and/or amplitudes from the vibrations of interest, and then modify these frequencies and/or amplitudes. For example, the control module  846  can increase the value of the measured frequencies at which peaks appear in the vibrations of interest  300 ,  306 ,  308 , can increase the value of the amplitudes of the peaks in the vibrations of interest  300 ,  306 ,  308 , or the like. The frequencies and/or amplitudes of the peaks in the vibrations of interest  300 ,  306 ,  308  can be increased by the same amount that the frequencies and/or amplitudes of the peaks in the baseline vibrations  400 ,  402  decreased, or may be increased by an amount that is at least partially based on the decrease in the peaks in the baseline vibrations  400 ,  402 . 
     The control module  846  can repeatedly monitoring changes in baseline vibrations generated by the control system  802  to monitor changes in the environmental conditions and using these changes to modify (e.g., correct) the information that is determined from the vibrations of interest generated by an object  200  circulating close to the sensing system  804 . 
     In one aspect, the control module  846  is configured to determine that the system  100  is malfunctioning based at least in part on the baseline vibrations. For example, the sensing control module  846  may be aware of the times at which the baseline vibrations are generated by the control system  802 . If the control module  846  does not detect the baseline vibrations at times that correspond to when the baseline vibrations are generated, then the control module  846  can determine that the system  800  is malfunctioning. Responsive to determining this, the sensing processor  812  can communicate one or more warning signals to another location, such as a repair facility, dispatch facility, or the like, to warn of the malfunction of the system  800 , and/or to request inspection, repair, maintenance, or the like, of the system  800 . 
     As a variant, the initialization programming instructions  850  are configured, while they are executed, to command the actuator  832 , to emit successively several first signals having the same intensity levels, while the control system stays preferably at the same location. In this variant the memorized set of measured data are determined by using averaging algorithm for example. 
     As a variant, the control system  802  is devoid of calibration device and the actuator comprises only one functioning mode which is the track configuration mode. In this variant after the initialization of the sensing processor  812 , control systems  102  are installed along the track for each sensing system  804  and functions has described in the first embodiment described above. In this variant, the memorized sets of measured data correspond to the designated signatures or waveforms of  FIG. 5 . 
       FIG. 9  illustrates a flowchart of the steps of a method for detecting the presence of a vehicle on a railway track realized by the detecting system  800 . 
     First, the method comprises an initialization step  900 , then after the finalization of the initialization step the method comprises, a security step  902 , a control step  904  and a detecting step  906 . 
     The initialization step is presented in more details on  FIG. 10 . The initialization step comprises:
         an emission sub-step  900 A, during which, the controller executes the initialization programming instructions  850  in order to emit the first signal;   a sending sub-step  900 B, the controller  822  executing the initialization programming instructions  850  in order to send the first message to the sensing processor  812 ;   a monitoring sub-step  900 C, the sensing processor  812  monitoring the sensing system; and   a configuring sub-strep  900 D, during which the configuration device  842  configures the detection module  840  in function of the received first signal and the received configuration data. More especially, a set of measured data relative to the received first signal are memorized and are associated with the configuration data and notably with a type of detected object, according to, for example, the signal intensity comprised in the associated configuration data. Preferentially the memorized set of measured data is associated also with a location of the type of detected object determined in function of the location of the control system  802  comprised in the configuration data.       

     During the initialization step the actuator  832  is configured in the track configuration mode. 
     After the initialization, step the sensing processor  812  is initialized and is configured for detecting objects moving on the track close to the sensing system  804 . Advantageously, after the initialization step the control system  802  is taken off the wheels and installed close to the sensing system  804  at a predetermined location. 
     After the initialization step the actuator  832  is configured in the supervision mode. 
     Advantageously, the initialization step  900  is repeated: at predetermined time intervals, or each time an activator on the initialization device is activated, or when the initialization device is not moving for a predetermined amount of time. 
     Advantageously the control system  802  is moved along the track at predetermined locations and the initialization step  900  is repeated several times with first signals having different intensity levels, corresponding to different type of objects, such as a car, an animal, a train, a road vehicle . . . 
     The security step  902  is presented in more details on  FIG. 11 . The security step  902  comprises:
         a sending sub-step  902 A, during which the calibration device output the third signal;   a monitoring sub-step  902 B, the sensing processor monitoring the sensing system; and   a determining step  902 C, during which the security module compares the third signal amplitude with a window threshold to determine if at least one of the calibration device or the sensing device  806  has moved. When intensity level of the third signal exceeds the window threshold, the security module  844  determines that the sensing device has moved or the calibration device has moved. Thus, this determining sub-step includes verifying if at least one of the calibration device or sensing system has moved.       

     Advantageously, when the window threshold is exceeded, the sensing processor  812  sends an alert, that the fiber optic cable or acoustic device at the location have changed, to a supervision central of the railway track. 
     The control step  904  is presented in more details on  FIG. 12 . The control step  904  comprises:
         an emitting sub-step  904 A, during which the control system  802  output the fourth signal;   a sending sub-step  904 B, the control system  802 , sending to the sensing processor  812 , a second message comprising control data chosen among, location of the control device, intensity/magnitude of the fourth signal, emission time of the fourth signal;   a monitoring sub-step  904 C, the sensing processor monitoring the sensing system;   a modifying sub-step  904 D, during which the sensing processor modifies the memorized set of measured data or measured data relative to a received second signal in function of the received fourth signal. During the modifying sub-step the sensing processor compares the received fourth signal with pre-memorized data in order to detect changing in environmental conditions of the railway track, then at least one of the memorized set of measured data or measured data relative to the received second signal being modified in function of the detected changes in environmental conditions of the railway track.       

     The detecting step  906  is presented in more details on  FIG. 13 . The detecting step  906  comprises:
         a commissioning step  906 A, during which an object, notably a train, moves on the track close to the sensing system; The movement of the train induces vibrations corresponding to a second signal measured by the sensing system,   a monitoring sub-step  906 B, the sensing processor monitoring the sensing system; and   a determination sub-step  906 C, during which the sensing processor compares the received second signal with each memorized set of measured data in order to determine a type of detected object circulating on the railway track and preferentially also its location.       

     Advantageously, before the determination sub-step, the control step  904  is realized to amend the measured data relative to a received second signal in function of detected changes in environmental conditions. 
     At step  904 C, for example, a determination may be made as to whether the peaks or other shapes of the frequency spectrum of the vibrations of interest more closely match the peaks or other shapes of a signature or waveform than one or more other signatures or waveforms. For example, the corrected vibrations of interest may closely match the peaks of a signature or waveform representative of a particular object of interest, a particular speed of an object of interest, a particular location of an object of interest, or the like. On the other hand, if the corrected vibrations of interest do not match one or more of the signatures or waveforms, then the vibrations of interest may not represent an object of interest, a speed of an object of interest, a location of an object of interest, or the like. Then, flow of the method can return to  906 A and  906 B for additional vibrations to be sensed. 
     At step  904 C, information about an object of interest is determined based at least in part on the vibrations of interest. For example, the object of interest, the location of the object of interest, the speed of the object of interest, or the like, that is associated with a signature or waveform that more closely matches the corrected vibrations of interest than other signatures or waveforms may be identified. 
     Therefore, it appears that the control step  904  impact the detecting step  906  and allows to adapt the detecting step to changes in environmental conditions of the railway track. 
     Clearly, the principle of the invention remaining the same, the embodiments and the details of production can be varied considerably from what has been described and illustrated purely by way of non-limiting example, without departing from the scope of protection of the present invention as defined by the attached claims. 
     Components of the systems described herein may include or represent hardware circuits or circuitry that include and/or are connected with one or more processors, such as one or more computer microprocessors. The operations of the methods described herein and the systems can be sufficiently complex such that the operations cannot be mentally performed by an average human being or a person of ordinary skill in the art within a commercially reasonable time period. For example, the examination of the vibrations may take into account a large amount of information, may rely on relatively complex computations, and the like, such that such a person cannot complete the examination of the vibrations within a commercially reasonable time period to correct vibrations measured during passage of a vehicle. The hardware circuits and/or processors of the systems described herein may be used to significantly reduce the time needed to obtain and examine the vibrations. 
     As used herein, a structure, limitation, or element that is “configured to” perform a task or operation is particularly structurally formed, constructed, programmed, or adapted in a manner corresponding to the task or operation. For purposes of clarity and the avoidance of doubt, an object that is merely capable of being modified to perform the task or operation is not “configured to” perform the task or operation as used herein. Instead, the use of “configured to” as used herein denotes structural adaptations or characteristics, programming of the structure or element to perform the corresponding task or operation in a manner that is different from an “off-the-shelf” structure or element that is not programmed to perform the task or operation, and/or denotes structural requirements of any structure, limitation, or element that is described as being “configured to” perform the task or operation. 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the inventive subject matter without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the inventive subject matter, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to one of ordinary skill in the art upon reviewing the above description. As used herein, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, as used herein, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 
     This written description uses examples to disclose several embodiments of the inventive subject matter and also to enable a person of ordinary skill in the art to practice the embodiments of the inventive subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the inventive subject matter may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the clauses if they have structural elements that do not differ from the literal language of the clauses, or if they include equivalent structural elements with insubstantial differences from the literal languages of the clauses. 
     The foregoing description of certain embodiments of the inventive subject matter will be better understood when read in conjunction with the appended drawings. To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between hardware circuitry. Thus, for example, one or more of the functional blocks (for example, processors or memories) may be implemented in a single piece of hardware (for example, a general purpose signal processor, microcontroller, random access memory, hard disk, and the like). Similarly, the programs may be stand-alone programs, may be incorporated as subroutines in an operating system, may be functions in an installed software package, and the like. The various embodiments are not limited to the arrangements and instrumentality shown in the drawings. 
     As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “an embodiment” or “one embodiment” of the inventive subject matter are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.