KR20240092361A - Railway Vehicle Speed and Position Measurement System Using Single Accelerometer and GPS, Method for Measuring Railway Vehicle Speed and Position Using the Same - Google Patents

Abstract

The present invention is an accelerometer that is mounted on the axle of a railway vehicle and measures the vertical vibration acceleration of the railway vehicle, a GPS unit that measures the speed and position of the railway vehicle while operating in an open area, and receives measurement data from the accelerometer and the GPS unit. Calculate the speed of the railway vehicle by analyzing the acceleration signal measured in the STFT method, correct the GPS unit measured speed data in the shaded area where the GPS signal does not reach, and use the corrected GPS unit measured speed data to calculate the speed of the railway vehicle. Railroad vehicle speed using a single accelerometer and GPS, which consists of a microprocessor unit that corrects the position data of all sections, a communication module that transmits the corrected speed and position data values of the railroad vehicle generated by the microprocessor unit to the railroad vehicle control unit, and It is about a position measurement system.

Description

Railway Vehicle Speed and Position Measurement System Using Single Accelerometer and GPS, Method for Measuring Railway Vehicle Speed and Position Using the Same}

The present invention relates to a system for measuring the speed and position of a railway vehicle, and more specifically, to an accelerometer mounted on the axle of a railway vehicle and measuring the vertical vibration acceleration of the railway vehicle, and the speed and position of the railway vehicle during open ground operation. Receives measurement data from the GPS unit, accelerometer, and GPS unit that measures the speed, analyzes the acceleration signal measured from the accelerometer using the STFT method, calculates the speed of the railway vehicle, and measures the speed of the GPS unit in shaded areas where GPS signals do not reach. A microprocessor unit that corrects the data and corrects the position data of all sections in which the railway vehicle operates using the calibrated GPS unit measured speed data, and the corrected speed and position data values of the railway vehicle generated by the microprocessor unit are used to control the railway vehicle It relates to a railway vehicle speed and position measurement system using a single accelerometer and GPS, which consists of a communication module that transmits to the secondary station.

During the operation of the railway vehicle, the running speed of the railway vehicle is measured to prevent collision accidents by adjusting the running interval with the preceding vehicle, and the driving speed is adjusted through braking or propulsion of the railway vehicle to ensure safety established for each operation section. maintain speed.

The speed of a railway vehicle is mainly determined through a tachometer installed on the axle, and the tachometer calculates the running speed of the train using a speed pulse proportional to the rotational speed of the axle.

However, as the wheels of railway vehicles gradually wear out due to friction with the rail surface, the diameter of the wheels decreases. To ensure stable running of railway vehicles, the tread surface of the wheels is periodically turned to maintain the tread profile in an optimal state. In the process of maintaining the wheel diameter, a decrease occurs.

As the diameter of the wheel decreases, the error between the rotational speed of the axle measured through the tachometer and the running speed of the railway vehicle increases, especially when abnormal wheel behavior such as slip or slide between the wheel and rail occurs. Because the tachometer's speed measurement result is measured lower than the vehicle's actual running speed, it acts as a major risk factor for the safe operation of railroad vehicles.

In order to prevent this problem, Japanese Registered Patent Publication JP7125785 (registered on August 25, 2022) receives reflected waves from a speed measurement target through a plurality of receiving means, and then receives them from a receiving means consisting of a plurality of antennas through a signal processing means. A speed measurement device, speed measurement program, recording medium, and speed measurement method that can calculate the speed of the speed measurement object by calculating the phase variation between reflected waves are presented.

However, the above driving speed measurement method requires installing multiple receiving means in the speed measurement area, which increases the cost of building a speed measurement system, and has the disadvantage of not being able to calculate the speed of the speed measurement target in sections where the receiving means are not installed. has.

In addition, in Japanese Registered Patent Publication JP6349534 (registered on June 20, 2018), a laser beam is irradiated from a laser light source installed on a railway vehicle to an object on the rail laying side, and the scattered laser beam is received by a differential LDV light receiving element to extract a Doppler signal. , a railway vehicle speed measurement method and a measuring device for measuring the speed of a railway vehicle are proposed.

However, this method of measuring running speed also requires installing rail-laying objects in each speed measurement area, which increases the cost of building a speed measurement system. In sections where rail-laying objects are not installed, the speed of the speed measurement target cannot be calculated. In addition, in the event of bad weather such as fog, heavy snow, or heavy rain, the irradiation and reception of the laser light source could not be performed stably, making it difficult to calculate the speed of the speed measurement target.

Japanese Registered Patent Publication JP7125785 (registered on August 25, 2022) Japanese Registered Patent Publication JP6349534 (registered on 2018.06.20)

In an embodiment of the present invention, the railroad car speed measurement system is formed on the railroad car, and a separate speed measurement means is not installed or provided in the running section of the railroad car, thereby minimizing the increase in the cost of building a speed measurement system. The purpose is to provide a railway vehicle speed and position measurement system and measurement method that can be used.

The purpose of the embodiment of the present invention is to provide a railway vehicle speed and position measurement system and measurement method in which speed measurement accuracy and reliability do not decrease due to external environmental factors such as bad weather.

A railway vehicle speed and position measurement system using a single accelerometer and GPS according to the present invention includes an accelerometer mounted on a railway vehicle axle to measure the vertical vibration acceleration of the railway vehicle; A GPS unit that measures the speed and position of railway vehicles while operating in open areas; By receiving measurement data from the accelerometer and GPS unit, ⅰ) calculate the speed of the railway vehicle by analyzing the acceleration signal measured from the accelerometer using the STFT (Short Time Fourier Transform) method ⅱ) GPS in shaded areas where GPS signals do not reach correcting the unit measured speed data iii) a microprocessor unit correcting the position data of the railway vehicle using the corrected GPS unit measured speed data; It consists of a communication module that transmits the corrected speed and position data values of the railway vehicle generated by the microprocessor unit to the railway vehicle control unit.

According to an embodiment of the present invention, vibration frequency analysis is performed by dividing the vibration signal measured through an accelerometer into regular time intervals, and the vibration frequency is i) generated by rolling vibration due to interaction between the wheels and rails of a railway vehicle. Wheel vibration frequency (f _w ) ⅱ) It consists of sleeper vibration frequency (f _s ) caused by the difference in rail track rigidity according to the distance from the sleeper supporting the rail, and the vibration frequency formula is: and And by calculating the speed (v) of the railway vehicle from the wheel diameter (d) and sleeper arrangement spacing (s) of the railway vehicle, and performing STFT analysis for each time section, errors in wheel diameter and sleeper arrangement spacing are compensated for. Calculate the speed of

According to an embodiment of the present invention, the speed data reception status of the GPS unit is detected in real time through a microprocessor unit, and when the speed data transmission of the GPS unit is interrupted due to the railway vehicle entering the shadow area, the speed data reception status of the railway vehicle calculated from the accelerometer is detected. The speed is corrected by adding or subtracting from the speed just before the GPS unit stopped receiving speed data.

The method for measuring the speed and position of a railway vehicle using a single accelerometer and GPS according to the present invention includes a vibration acceleration measurement step of measuring the vertical vibration acceleration of the railway vehicle through an accelerometer mounted on the axle of the railway vehicle; A GPS measurement step of measuring the running speed of a railway vehicle from a GPS unit mounted on the railway vehicle; A signal transmission step of transmitting the vibration acceleration measurement signal of the accelerometer and the GPS signal of the GPS unit to the microprocessor unit; A frequency analysis step using the STFT (Short Time Fourier Transform) method, in which the measurement signal of the vibration acceleration measured by the accelerometer through a microprocessor unit is divided into regular time intervals and the divided frequencies are analyzed by Fourier transformation; A traveling speed calculation step of calculating the traveling speed of the railway vehicle from the divided frequency analysis results through a microprocessor unit; The microprocessor unit detects GPS signal reception in real time, i) when GPS signal reception is detected, the driving position and speed data of the railway vehicle included in the GPS signal is confirmed as the final data ii) when GPS signal non-reception is detected, the shaded area It is judged as a driving state, and finally, the driving position and speed data of the railway vehicle generated by adding and subtracting the driving speed data of the railway vehicle calculated in the driving speed calculation stage to the GPS unit measured speed data included in the GPS signal for which reception was detected is the final result. A driving speed correction step confirmed by data; It consists of a data transmission step of transmitting the final data determined in the GPS signal detection and driving speed correction step to the control unit through a communication module; GPS signal detection is performed continuously from the vibration acceleration measurement step to the data transmission step. .

According to an embodiment of the present invention, in the frequency analysis step, the vibration signal measured by the accelerometer is divided into regular time intervals and vibration frequency analysis is performed using the STFT method for each time section. In the traveling speed calculation step, i) the wheels of the railway vehicle Wheel vibration frequency (f _w ) formula generated by rolling vibration due to interaction between rails and rails , d is the wheel diameter of the railway vehicle ⅱ) The sleeper vibration frequency (f _s ) caused by the difference in rail track stiffness according to the distance from the sleeper supporting the rail is the formula , s calculates the speed (v) of the railway vehicle from the sleeper placement interval.

According to an embodiment of the present invention, when a railway vehicle is driven in an open area where GPS signals can be easily received, the speed and position of the railway vehicle are measured from the GPS signal, and when the GPS signal is not detected due to driving in a shaded area, the shape error of the wheels is measured. The speed of the railway vehicle is calculated by analyzing the vibration acceleration using the STFT method from the vibration resulting from the rolling vibration and the change in the rigidity of the rail depending on whether or not it is supported between the sleeper and the rail, and then the final received GPS data is corrected using the calculation result. By doing so, there is an effect of accurately measuring the traveling speed and position of the railway vehicle in the shaded area.

According to an embodiment of the present invention, since the speed measurement system is mounted on the axle of a railway vehicle, system installation is easy and system construction costs can be reduced.

According to an embodiment of the present invention, there is no need to build a separate measurement system on the track to measure the speed of railway vehicles, thereby reducing system construction costs and maintaining consistent accuracy and reliability regardless of external environmental changes such as bad weather. It has the effect of obtaining speed and position measurement results.

According to an embodiment of the present invention, the vibration frequency is analyzed using the STFT method to calculate the speed, so that even if the irregularity of the vibration frequency increases due to slip between wheels and rails while the railway vehicle is running, the speed is calculated individually for each local section, It has the effect of obtaining highly reliable measurement results compared to speeds calculated collectively from the entire measured section.

According to an embodiment of the present invention, the vibration frequency is analyzed using the STFT method to calculate the speed, thereby reducing the load on the microprocessor unit during the driving speed calculation process.

Figure 1 is a diagram showing the configuration of a railway vehicle speed and position measurement system using a single accelerometer and GPS according to an embodiment of the present invention.
Figure 2 is a diagram showing the cross-sectional structure of the wheels and axles of a railway vehicle.
Figure 3 is a diagram showing the error between the cross-sectional shape of a railway vehicle wheel tread in a design that forms a complete circle and the cross-sectional shape of an actual railway vehicle wheel tread.
Figure 4 is a diagram showing the planar structure of a track composed of a rail and a sleeper and the change in rail stiffness according to the distance from the support point of the sleeper.
Figure 5 is a graph showing the change in railway vehicle speed over time measured through an accelerometer.
Figure 6 is a graph showing the results of analysis of the vibration acceleration in the height direction of a railway vehicle through the STFT method.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

A detailed explanation will be given focusing on the parts necessary to understand the operation and action according to the present invention.

While describing embodiments of the present invention, description of technical content that is well known in the technical field to which the present invention belongs and that is not directly related to the present invention will be omitted.

This is to convey the gist of the present invention more clearly without obscuring it by omitting unnecessary explanation.

Additionally, when describing the components of the present invention, different reference numerals may be assigned to components with the same name depending on the drawings, and the same reference numerals may be assigned to different drawings.

However, even in this case, it does not mean that the corresponding components have different functions depending on the embodiment or that they have the same function in different embodiments, and the function of each component is different in the corresponding embodiment. The judgment should be made based on the description of each component in .

In addition, the technical terms used in this specification, unless specifically defined differently in this specification, should be interpreted as meanings commonly understood by those skilled in the art in the technical field to which the present invention pertains, and should not be overly comprehensive. It should not be interpreted as meaningless or in an excessively reduced meaning.

Additionally, as used herein, singular expressions include plural expressions, unless the context dictates otherwise.

In the present application, terms such as “consists of” or “comprises” should not be construed as necessarily including all of the various components or steps described in the specification, and some of the components or steps may include It may not be included, or it should be interpreted as including additional components or steps.

The railway vehicle speed and position measurement system using a single accelerometer and GPS according to an embodiment of the present invention includes an accelerometer (1) that measures the vertical vibration acceleration of the railway vehicle, as shown in FIG. 1, and an open area operation of the railway vehicle. A GPS unit (2) that measures speed and position, and a microprocessor unit (MPU) that receives measurement data from the accelerometer (1) and GPS unit (2) to correct the speed and position data of the railway vehicle. 3), and a communication module (4) that transmits the corrected speed and position data values of the railway vehicle to the railway vehicle control unit.

As shown in Figure 2, the accelerometer (1) is mounted on the axle of the railway vehicle, which is the rotation axis of the wheel (10) that transmits the driving force of the railway vehicle to the rail of the track, and is a size sensor system consisting of an elastic element such as a spring and a mass body. It consists of a structure that measures acceleration through mass displacement measurement.

The accelerometer (1) is a moving coil type that measures the electromotive force generated when the relative positions of the magnet and coil mounted on the mass body change, and the displacement of the mass body is measured through a piezoelectric element, capacitance, strain gauge, or differential transformer, respectively. It operates in any one of the typical, capacitive, strain gauge, servo, or differential transform types, or in a combination thereof.

The cross-sectional shape of the thread of the wheel 10 of a railway vehicle is designed to be completely circular, but complex factors such as errors occurring during processing of the tread surface of the wheel 10 or wear caused by contact with the rail surface while the railway vehicle is running For some reason, the actual cross-sectional shape of the tread surface of the wheel 10 does not form a circular cross-section as shown in FIG. 3.

Accordingly, the distance from the center of the axle to the tread surface of the wheel 10 is formed differently, so that rolling vibration occurs as the height from the upper surface of the rail to the center of the axle changes when the railway vehicle is running.

In addition, as shown in Figure 4, the railway track includes a rail that supports the wheels 10 and guides the direction of travel of the railway vehicle, and a plurality of sleepers (20) installed between the ground and the rail to support the lower part of the rail. ), and each sleeper 20 is spaced apart from each other at regular intervals along the length of the rail.

When the load of the railway vehicle is transferred to the track through the contact point with the wheel 10, the rigidity of the rail is formed differently depending on the distance from the point supported by the sleeper 20, and the rigidity of the rail is formed differently depending on the distance from the point supported by the sleeper 20. The rail stiffness reaches its maximum level at the support point and gradually decreases as the distance from the sleeper 20 increases, reaching its minimum level at the midpoint between adjacent sleepers 20.

When a railway vehicle is running, the farther the wheel position moving along the rail is from the sleeper 20, the more vertical displacement of the rail occurs, and the closer the wheel 10 position is to the sleeper 20. As the amount of vertical displacement of the rail decreases, vertical vibration of the wheel 10 occurs.

The accelerometer 1 measures the vibration acceleration generated from rolling vibration caused by the tread shape of the wheel 10 and the vertical vibration acceleration of the railway vehicle generated by changes in the rigidity of the rail.

The GPS unit (2) analyzes the radio waves received from each of the four artificial satellites, calculates the time information contained in the radio waves received from the three satellites using the triangulation method, measures the distance between each satellite and the measurement location, and then It consists of a GPS (Global Positioning System) device that can determine the exact location and moving speed of railway vehicles by correcting errors through radio waves received from satellites, and measures the running speed and position of railway vehicles while operating in open areas.

The microprocessor unit (MPU, Micro Processor Unit, 3) receives the measured data from the accelerometer (1) and the GPS unit (2), and converts the acceleration signal measured from the accelerometer (1) into STFT (Short Time Fourier Transform). Conversion) method is used to calculate the speed of the railway vehicle.

The acceleration signal measured by the accelerometer (1) varies over time due to changes in speed due to acceleration or deceleration of the railway vehicle, rolling vibration due to the shape of the tread of the wheels (10), or changes in the rigidity of the rail according to the relative position with the sleeper (20). Since it continuously changes according to the flow, the acceleration signal consists of a signal whose frequency continuously changes over time, and as shown in Figure 5, the speed of the railway vehicle calculated from the acceleration signal also continuously changes over time. .

When the acceleration signal measured by the accelerometer (1) is analyzed collectively for the entire signal section, it is difficult for the analyzed result to properly reflect the change in frequency over time, which may cause errors in the calculated speed of the railway vehicle. .

Therefore, in the microprocessor unit 3 of the present invention, the acceleration signal measured by the accelerometer 1 is divided into a plurality of sections at regular time intervals through the STFT method, and Fourier transform is performed for each signal of the divided local section, so that the accelerometer ( The size of the error that occurs in the process of calculating the speed of the railway vehicle from the acceleration signal measured in 1) can be reduced.

As shown in FIG. 6, the microprocessor unit 3 performs vibration frequency analysis of the vibration signal measured by the accelerometer 1 through the STFT method, and the analyzed vibration frequency is the difference between the wheel 10 and the rail of the railway vehicle. The wheel vibration frequency (f _w ) generated by rolling vibration due to interaction, and the sleeper vibration frequency (f _s ) generated by the difference in rail track stiffness depending on the distance from the sleeper 20 supporting the rail. It comes true.

The wheel vibration frequency (f _w ) is It is expressed in the formula, and the speed (v) of the railway vehicle can be calculated from the wheel vibration frequency (f _w ) and the diameter (d) of the wheel (10) of the railway vehicle, and the tread surface of the wheel (10) that does not form a complete circle. As rolling vibration occurs due to the shape, the vibration frequency (f _w ) data according to the diameter (d) that changes with time is analyzed using the STFT method to calculate the velocity individually for each local section.

In particular, if slip occurs between the wheel 10 and the rail while the railway vehicle is running, the irregularity of the measured wheel vibration frequency (f _w ) increases, and the speed of the vibration frequency by local section by the STFT method Through calculation, the influence of errors caused by slip can be reduced.

Additionally, the sleeper vibration frequency (f _s ) is It is expressed in the formula, and the speed of the railway vehicle (v) can be calculated from the sleeper vibration frequency (f _s ) and the sleeper 20 arrangement spacing (s), and the sleepers are not spaced at exactly the same intervals, so changes occur. (20) The sleeper vibration frequency (f _s ) data according to the arrangement spacing (s) is analyzed using the STFT method to calculate the speed individually for each local section.

For example, if the design diameter (d) of the wheel 10 is 850 mm and the running speed (v) of the railway vehicle is 300 km/h, a wheel vibration frequency (f _w ) of 31.2 Hz occurs, and the wheel vibration frequency (f _w ) forms a vibration that includes a frequency of integer multiples of 31.2 Hz in addition to the frequency of 31.2 Hz.

And when the sleeper 20 arrangement spacing (s) is 0.6 m and the running speed (v) of the railway vehicle is 300 km/h, a sleeper vibration frequency (f _s ) of 138 Hz is formed, and the wheel vibration frequency (f _w ) The sleeper vibration frequency (f _s ) must form a constant vibration pattern over time, but the occurrence of rolling vibration due to the non-uniformity of the tread shape of the actual wheel 10, the error in the arrangement interval s of the sleeper 20, and the wheel 10 ) and the occurrence of slip between rails, the acceleration signal measured by the accelerometer 10 consists of a signal whose frequency changes continuously over time, causing an error in the calculated running speed of the railway vehicle.

Therefore, by compensating for errors in the diameter of the wheel 10 and the arrangement spacing of the sleepers 20 by calculating the speed of the wheel vibration frequency (f _w ) and the sleeper vibration frequency (f _s ) for each local section using the STFT method, Compared to measuring the speed of railway vehicles all at once, it allows the speed of railway vehicles to be calculated more accurately.

When a railway vehicle is driven in a shaded area such as a tunnel where the GPS signal does not reach the GPS unit (2), it is impossible to form location and speed data of the railway vehicle through the GPS signal, so the railway calculated by the microprocessor unit (3) Based on the speed of the vehicle, the GPS unit (2) corrects the railway vehicle speed data on the GPS signal finally received, and corrects the location data of the railway vehicle based on the calibrated GPS unit (2) measured speed data. Generates calibrated rail vehicle speed and position data.

The corrected speed and position data values of the railway vehicle generated by the microprocessor unit (3) are transmitted to the railway vehicle control unit through the communication module (4), allowing the running speed and position of the railway vehicle in the shaded area to be more accurately identified. Let it happen.

At this time, the microprocessor unit 3 detects in real time whether the GPS unit 2 receives speed and position data from the GPS signal, and when it detects that the speed and position data of the GPS unit 2 are not received, the railway vehicle It is judged to be driving in this shaded area, and the speed of the railway vehicle calculated from the accelerometer (1) through the microprocessor unit (3) is added and subtracted from the speed and position data of the GPS unit (2) that was finally confirmed to be received just before the reception was stopped. Correct it.

The railway vehicle speed and position measurement system using a single accelerometer and GPS according to the present invention can be installed on a bogie or axle of a railway vehicle, thereby lowering the difficulty of installation and reducing installation costs by not requiring structural changes to the railway vehicle. It has the advantage of being able to

The method of measuring the speed and position of a railway vehicle using a railway vehicle speed and position measurement system using a single accelerometer and GPS according to the present invention configured as above will be described as follows.

In the vibration acceleration measurement step (S10), the rolling vibration generated from the surface shape of the wheel 10 and the vibration generated from the change in the rigidity of the rail according to the position of the support point of the sleeper 20 are measured through the accelerometer 1 mounted on the axle of the railway vehicle. Measure the vertical vibration acceleration of the railway vehicle generated from.

In the GPS measurement step (S11), the running speed of the railroad car is measured from the GPS unit mounted on the railroad car, and in the signal transmission step (S20), the vibration acceleration measurement signal from the accelerometer (1) and the GPS signal from the GPS unit (2) are measured. It is transmitted to the microprocessor unit (3).

In the frequency analysis step (S30), the vibration acceleration measurement signal of the accelerometer 1 transmitted to the microprocessor unit 3 is divided at regular time intervals to form a plurality of vibration acceleration signal local sections, and the divided vibration acceleration signal local sections are formed. Vibration acceleration signal analysis is performed using the STFT (Short Time Fourier Transform) method, which performs Fourier transformation and analysis.

In the running speed calculation step (S40), the running speed of the railway vehicle is calculated from the results of the frequency analysis divided by the microprocessor unit 3.

The vibration acceleration measurement step (S10) to the traveling speed calculation step (S40) are performed continuously while the railway vehicle is running, and the vibration acceleration measurement step (S10) to the traveling speed calculation step (S40) are performed simultaneously with the GPS unit (2). Whether GPS signals are received is detected in real time through the microprocessor unit (3).

In the driving speed correction step (S50), whether a GPS signal is received is detected, and whether to perform driving speed correction is determined depending on whether the GPS signal is detected.

1. Detect GPS signal reception

When GPS signal reception is detected, the driving position and speed data of the railway vehicle included in the GPS signal are confirmed as the final data, and the final data of the confirmed driving position and speed of the railway vehicle are transmitted to the control unit through the communication module (4). A data transmission step (S60) is performed.

2. Detection of non-receipt of GPS signal

When non-reception of a GPS signal is detected, it is determined that the railway vehicle is driving in a shaded area, and the vibration acceleration is calculated in the traveling speed calculation step (S40) based on the GPS unit (2) measured speed data included in the GPS signal for which reception was last detected. By adding or subtracting the running speed data of the railway vehicle calculated through STFT analysis of the measurement signal, correction data for the running speed of the railway vehicle is generated.

Then, based on the generated running speed correction data, the position data of the final received GPS signal is corrected to generate correction data for the railway vehicle running position, final data of the railway vehicle running position and speed data are confirmed, and data is transmitted. In step S60, the final data of the confirmed railway vehicle driving position and speed data is transmitted to the control unit through the communication module 4.

GPS signal detection is performed continuously during the vibration acceleration measurement step (S10) to the data transmission step (S60), and during the driving speed correction step (S50) or data transmission step (S60) according to the detection of GPS signal non-reception, When the microprocessor unit (3) detects the GPS signal transmitted from the GPS unit (2), it determines that the railroad car has passed the shaded area, and the driving position and speed data of the railroad car included in the re-received GPS signal are finalized. It is confirmed as data, and the final data of the confirmed running position and speed of the railway vehicle is transmitted to the control unit through the communication module (4).

Although embodiments of the present invention have been described with reference to the above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features.

Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive, and the scope of the present invention described in the detailed description is indicated by the claims described later, and the meaning and meaning of the claims. The scope and all changes or modified forms derived from the equivalent concept should be construed as being included in the scope of the present invention.

1: Accelerometer 2: GPS unit
3: Microprocessor unit 4: Communication module
10: wheel 20: sleeper

Claims (5)

An accelerometer (1) mounted on the axle of a railway vehicle to measure the vertical vibration acceleration of the railway vehicle;
A GPS unit (2) that measures the speed and position of a railway vehicle while operating in an open area;
By receiving measurement data from the accelerometer (1) and GPS unit (2),
ⅰ) Calculate the speed of the railway vehicle by analyzing the acceleration signal measured by the accelerometer (1) using the STFT (Short Time Fourier Transform) method.
ⅱ) Calibrate the GPS unit (2) measured speed data in shaded areas where GPS signals do not reach.
iii) Calibrated position data of railway vehicles using calibrated GPS unit (2) measured speed data
A microprocessor unit (MPU, Micro Processor Unit, 3);
a communication module (4) that transmits the corrected speed and position data values of the railway vehicle generated by the microprocessor unit (3) to the railway vehicle control unit;
A railway vehicle speed and position measurement system using a single accelerometer and GPS, characterized in that it consists of. According to paragraph 1,
Vibration frequency analysis is performed by dividing the vibration signal measured through the accelerometer (1) into regular time intervals.
The vibration frequency is
ⅰ) Wheel vibration frequency (f _w ) generated by rolling vibration due to interaction between the wheels 10 of a railway vehicle and the rail.
ii) Sleeper vibration frequency (f _s ) caused by the difference in rail track stiffness depending on the distance from the sleeper 20 supporting the rail
It consists of the vibration frequency formula and And by calculating the speed (v) of the railway vehicle from the diameter (d) of the wheel (10) of the railway vehicle and the arrangement interval (s) of the sleeper (20), and performing STFT analysis for each time section, the diameter of the wheel (10) and the sleeper (20) are calculated. (20) A railway vehicle speed and position measurement system using a single accelerometer and GPS, which calculates the speed of the railway vehicle by compensating for errors in placement intervals. According to paragraph 2,
The speed data reception status of the GPS unit (2) is detected in real time through the microprocessor unit (3), and when the speed data transmission of the GPS unit (2) is interrupted due to the railroad vehicle entering the shaded area, the accelerometer (1) A railway vehicle speed and position measurement system using a single accelerometer and GPS, characterized in that the calculated speed of the railway vehicle is corrected by adding to or subtracting from the speed immediately before the GPS unit (2) stops receiving speed data. A vibration acceleration measurement step (S10) of measuring the vertical vibration acceleration of the railway vehicle through an accelerometer (1) mounted on the railway vehicle axle;
A GPS measurement step (S11) of measuring the running speed of the railway vehicle from the GPS unit mounted on the railway vehicle;
A signal transmission step (S20) of transmitting the vibration acceleration measurement signal of the accelerometer (1) and the GPS signal of the GPS unit (2) to the microprocessor unit (3);
The frequency analysis step of the STFT (Short Time Fourier Transform) method in which the measurement signal of the vibration acceleration measured by the accelerometer (1) is divided into regular time intervals through the microprocessor unit (3), and the divided frequencies are analyzed by Fourier transform ( S30);
A traveling speed calculation step (S40) of calculating the traveling speed of the railway vehicle from the results of frequency analysis divided by the microprocessor unit (3);
Detects in real time whether GPS signals are received through the microprocessor unit (3),
ⅰ) When GPS signal reception is detected, the driving position and speed data of the railway vehicle included in the GPS signal are confirmed as final data.
ⅱ) When non-reception of a GPS signal is detected, it is determined to be in a shaded area driving state, and finally, the driving speed of the railway vehicle calculated in the driving speed calculation step (S40) is added to the measured speed data of the GPS unit (2) included in the GPS signal for which reception was detected. Confirm the railway vehicle driving position and speed data generated by adding and subtracting data as final data
A driving speed correction step (S50);
A data transmission step (S60) of transmitting the final data confirmed in the GPS signal detection and driving speed correction step (S50) to the control unit through the communication module (4);
A method of measuring railway vehicle speed and position using a single accelerometer and GPS, wherein GPS signal detection is performed continuously during the vibration acceleration measurement step (S10) to the data transmission step (S60). According to clause 4,
In the frequency analysis step (S30), the vibration signal measured by the accelerometer 1 is divided into regular time intervals and vibration frequency analysis is performed using the STFT method for each time section,
In the driving speed calculation step (S40),
ⅰ) Wheel vibration frequency (f _w ) formula generated by rolling vibration due to interaction between the wheels 10 of a railway vehicle and the rail , d is the wheel diameter of the railway vehicle
ⅱ) Sleeper vibration frequency (f _s ) formula generated by the difference in rail track stiffness depending on the distance from the sleeper 20 supporting the rail , s is the sleeper 20 placement interval
A railway vehicle speed and position measurement method using a single accelerometer and GPS, characterized in that the speed (v) of the railway vehicle is calculated from .