JP2004271255A - Train own-vehicle position detection method and train own-vehicle position detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a system for detecting the position of a train or the like based on GPS information or the like transmitted by radio from a plurality of satellites circulating around the earth. <P>SOLUTION: A DGPS is applied to a moving body running system, and running for information measurement of the train 2 is performed, to thereby create a line information database. At the operation running time, an information processing part 22 uses a DGPS distance, when reception reliability is high, specifies the distance by using the DGPS distance as a primary value, operates an operation time line curvature equivalent value and comparing it with a known line curvature equivalent value, when reception reliability is in the medium degree, and specifies the distance based on the axle distance based on the axle rotational frequency, when the reception reliability is low. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and a system for detecting the position of a train based on GPS information transmitted by radio waves from a plurality of GPS satellites orbiting the earth.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a railway, as a method of detecting a position where a train is traveling, a wheel diameter is set to a known value, the number of rotations of the wheel is detected, and each time the wheel makes one revolution, a circle of a circle that becomes the outer periphery of the wheel Assuming that the train moves by one lap, the principle of multiplying the traveling distance is adopted, and a ground rail of an ATS (Automatic Train Stop: automatic train stop device) or an ATC (Automatic Train Control: automatic) installed near the track. A method of calculating the current position (for example, the distance from the starting point of the track) of the own vehicle on the track based on the accumulated traveling distance from the position of the ATS ground track, etc. Are known. In this method, the position coordinates of the ATS ground element and the like are measured in advance and are known.
[0003]
The rotation speed of the wheels described above is detected and calculated by a speed generator or the like attached to the axle of the train or the like. The position detection device mounted on the train integrates the travel distance of the train from the obtained rotation speed of the axle and the like, and specifies the current position on the train track from the position coordinates of the ATS grounding element and the like (for example, see Patent Reference 1).
[0004]
[Patent Document 1]
JP-A-10-24846 (pages 1-4, FIG. 1-3)
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional method of detecting the position of the own vehicle, the wheels of the train are worn by running, so that it is difficult to maintain accurate wheel diameter values in all vehicles at the initial set values. There is a problem that an error occurs as the period elapses. In addition, an error may be mixed in the accumulated traveling distance due to idling or sliding of wheels. Also, due to maintenance work, construction, etc., the ATS grounding element may be relocated from the initial position to another position. In this case, the position coordinates after the relocation are measured, and the data after the relocation are referred to as described above. There is a problem that the obtained vehicle position will not be accurate unless the position detection system is reset. Further, once the current position of the vehicle is lost, the current position cannot be detected and the system cannot return unless the vehicle arrives at a specific station whose coordinates and the like are known.
[0006]
The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to solve the problem of a train or the like based on GPS information transmitted by radio waves from a plurality of GPS satellites orbiting the earth. It is to provide a method and a system for detecting a position.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a train self-position detecting method according to claim 1 of the present invention uses a train-mounted device mounted on a train and a plurality of GPS satellites orbiting the earth to determine a current position of the train on a track. Is detected by the train mounted device,
In the train mounted device,
GPS receiving means for receiving GPS information transmitted by radio waves from the GPS satellites and calculating GPS position coordinates based on the GPS information;
Azimuth angle detection means for detecting the azimuth angle of the vehicle body when the train is running,
Axle rotation speed detecting means for detecting the axle rotation speed of the train,
Information storage means for storing a line information database that associates the latitude and longitude, the known line curvature equivalent value that is a value corresponding to the curvature of the line, and the distance,
Providing information processing means,
The information processing means, when the train runs on the track, calculates a reception reliability coefficient representing a reception reliability which is a degree of reliability at the time of receiving the GPS information,
When the reception reliability is determined to be high, the information processing unit specifies a current position of the train in the traveling section based on the GPS position coordinates,
When the reception reliability is determined to be medium, the information processing means sets a distance value based on the GPS position coordinates as an initial value, and sets the azimuth angle and the axle rotation at each time during operation driving. By calculating the operating line curvature equivalent value that is a value corresponding to the line curvature during operation from the train traveling speed obtained from the number, and comparing it with the known line curvature equivalent value in the line information database, Identify the current position of the train in the travel section,
When the reception reliability is determined to be low, the information processing unit specifies the current position of the train in the traveling section based on a distance based on the axle rotation speed.
It is characterized by.
[0008]
Further, the train self-position detecting method according to claim 2 of the present invention,
The method for detecting the position of a train vehicle according to claim 1,
When the reception reliability is determined to be low, the information processing unit sets a distance based on the axle rotation speed as an initial value, and sets the azimuth angle at each time point during operation traveling and the axle rotation speed. By calculating the operating line curvature equivalent value that is a value corresponding to the line curvature during operation from the train traveling speed obtained from the number, and comparing it with the known line curvature equivalent value in the line information database, Identify the current position of the train in the travel section
It is characterized by.
[0009]
Further, the train self-position detecting method according to claim 3 of the present invention,
The method for detecting the position of a train vehicle according to claim 1,
The GPS receiving means includes the azimuth detecting means,
When the reception reliability is determined to be low, the information processing unit specifies the current position of the train in the traveling section by a distance based on the axle rotation speed.
It is characterized by.
[0010]
In addition, the train self-position detecting method according to claim 4 of the present invention,
The method for detecting the position of a train vehicle according to claim 1,
The information measurement travel is performed by the train, and the information processing means detects each position of a travel section based on the GPS position coordinates at each time, and travels from a reference position based on the axle rotation speed. And calculates the value corresponding to the line curvature at each position in the traveling section from the azimuth angle at each time point and the train traveling speed obtained from the axle rotation speed, and calculates the line curvature as a known line curvature equivalent value. To be stored in the information database
It is characterized by.
[0011]
Further, the train self-position detecting method according to claim 5 of the present invention comprises:
In the method of detecting the position of a train vehicle according to claim 4,
With a reference position station whose position is being measured,
The GPS receiving means receives GPS information transmitted by radio waves from the GPS satellites and position correction information transmitted by radio waves from the reference position station, and receives DGPS position coordinates based on the GPS information and the position correction information. Is calculated,
When the train travels on the track, the information processing means calculates a reception reliability coefficient representing a reception reliability which is a degree of reliability at the time of receiving the GPS information and the position correction information.
It is characterized by.
[0012]
Further, the train self-position detecting method according to claim 6 of the present invention comprises:
In the method of detecting the position of a train vehicle according to claim 4,
The reception reliability coefficient is:
A first term that is a function of the number n of the GPS satellites used for receiving the GPS information, and that the larger the n is, the higher the reception reliability is;
It is a function of HDOP, which is the rate of decrease in horizontal position accuracy at an observation point on the earth.
The function must have at least one
It is characterized by.
[0013]
Further, the train self-position detecting method according to claim 7 of the present invention,
In the method of detecting the position of a train vehicle according to claim 4,
The reception reliability coefficient is:
A first term that is a function of the number n of the GPS satellites used for receiving the GPS information, and that the larger the n is, the higher the reception reliability is;
A second term that is a function of HDOP, which is a rate of decrease in horizontal position accuracy at an observation point on the earth, and that the smaller the HDOP is, the higher the reception reliability is;
This is a function of a differential correction data update time t, which is a time difference between the most recent time at which the position correction information was received and the time at which the reception reliability coefficient was calculated, and the smaller the t, the higher the reception reliability. Out of the third term
The function must have at least one
It is characterized by.
[0014]
Further, the train self-position detecting method according to claim 8 of the present invention,
In the method for detecting the position of a train vehicle according to claim 7,
The value of the differential correction data update time t is set to a very large value.
It is characterized by.
[0015]
In addition, the train self-position detecting method according to claim 9 of the present invention,
In the method for detecting the position of a train vehicle according to claim 7,
The reception reliability coefficient is:
A function obtained by multiplying the sum of the first and second terms by the third term
It is characterized by.
[0016]
In addition, the train self-position detecting method according to claim 10 of the present invention,
In the method for detecting the position of a train vehicle according to claim 5,
When the information processing means specifies the current position of the train in the traveling section based on the DGPS position coordinates, the information processing means includes, among the DGPS coordinate information stored in the information storage means by the information measurement travel, the operation travel A line connecting the second position and the third position, which is a position of two pieces of coordinate information close to the first position which is a position obtained from the GPS information and the position correction information at the time, and connecting the second position and the third position The current position of the train shall be the position where the vertical line drawn from the first position crosses the line segment
It is characterized by.
[0017]
Further, the train self-position detecting method according to claim 11 of the present invention,
In the method for detecting the position of a train vehicle according to claim 5,
The information processing means, when performing a comparison between the operational line curvature equivalent value and the known line curvature equivalent value, the known line curvature equivalent value data group and the operational line curvature equivalent value data group, Displaced by a certain distance, the deviation coefficient which is the sum of the squares of the differences between the operational line curvature equivalent value data and the known line curvature equivalent value data is minimized, or the operational line curvature equivalent value data and the Identifying the distance corresponding to the case where the value of the cross-correlation coefficient of the known track curvature equivalent value data is the maximum as the current position of the train on the track
It is characterized by.
[0018]
In addition, the train self-position detecting method according to claim 12 of the present invention,
In the method for detecting the position of a train vehicle according to claim 5,
The information processing means, when it is determined that the reception reliability is high, according to a ratio of the travel distance calculated by the DGPS position coordinates to the travel distance calculated by the axle rotation speed, Correcting the wheel diameter value of the train when calculating the running distance of the train from numbers
It is characterized by.
[0019]
In addition, the train self-position detection system according to claim 13 of the present invention,
A train-mounted device mounted on the train,
A system having a plurality of GPS satellites orbiting the earth, wherein the current position of the train on a track is detected by the train-mounted device,
The train mounted device,
GPS receiving means for receiving GPS information transmitted by radio waves from the GPS satellites and calculating GPS position coordinates based on the GPS information;
Azimuth angle detection means for detecting the azimuth angle of the vehicle body or bogie when the train is running,
Axle rotation speed detecting means for detecting the axle rotation speed of the train,
Information storage means for storing a line information database that associates the latitude and longitude, the known line curvature equivalent value that is a value corresponding to the curvature of the line, and the distance,
Equipped with information processing means,
The information processing means, when the train runs on the track, calculates a reception reliability coefficient representing a reception reliability which is a degree of reliability at the time of receiving the GPS information,
When the reception reliability is determined to be high, the information processing unit specifies a current position of the train in the traveling section based on the GPS position coordinates,
When the reception reliability is determined to be medium, the information processing means sets a distance value based on the GPS position coordinates as an initial value, and sets the azimuth angle and the axle rotation at each time during operation driving. By calculating the operating line curvature equivalent value that is a value corresponding to the line curvature during operation from the train traveling speed obtained from the number, and comparing it with the known line curvature equivalent value in the line information database, Identify the current position of the train in the travel section,
When the reception reliability is determined to be low, the information processing unit specifies the current position of the train in the traveling section based on a distance based on the axle rotation speed.
It is characterized by.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
FIG. 1 is a block diagram showing a configuration of a train vehicle position detection system according to an embodiment of the present invention.
[0022]
As shown in FIG. 1, the train-owned-vehicle position detection system 100 includes a train-mounted device 20, a reference position station 3, and GPS satellites G1, G2, G3,..., Gn.
[0023]
The train mounting device 20 is mounted on a train 2 running on a railway line 1. The reference position station 3 is a public reference station, and the position of the reference position station 3 is known in advance by measurement or the like. The reference position station 3 has a transmission antenna 31, and transmits position correction information on the position, time, and the like of the reference position station 3 by radio waves.
[0024]
The plurality of GPS satellites G1 to Gn are artificial satellites orbiting the earth, and their positioning codes, orbit information of the transmitting GPS satellite (information about the three-dimensional position coordinates and time of the transmitting GPS satellite, etc. GPS information is transmitted by radio waves.
[0025]
Therefore, the train-mounted device 20, the plurality of GPS satellites G1 to Gn, and the reference base station 3 constitute a DGPS (Differential Global Positioning System).
[0026]
The above-described train mounting device 20 includes an information processing unit 22, an information storage unit 23, a first antenna 24, a second antenna 25, a GPS processing unit 26, a differential reception unit 27, an azimuth detection unit 28, And an axle rotation speed detecting unit 29. Here, the information processing unit 22 corresponds to an information processing unit in the claims, and the information storage unit 23 corresponds to an information storage unit in the claims. The first antenna 24, the GPS processing unit 26, the second antenna 25, and the differential receiving unit 27 correspond to a GPS receiving unit in the claims. Further, the azimuth angle detection unit 28 corresponds to an azimuth angle detection unit in the claims. Further, the axle rotation speed detecting section 29 corresponds to an axle rotation speed detecting means in the claims.
[0027]
The first antenna 24 detects a radio wave transmitted from the GPS satellite G1 or the like, and outputs the detected radio wave to the GPS processing unit 26. The second antenna 25 detects a radio wave transmitted from the reference position station 3 and outputs the detected radio wave to the differential receiving unit 27. The differential receiving unit 27 obtains the position correction information from the radio wave detected by the second antenna 25 and outputs this to the GPS processing unit 26. The GPS processing unit 26 detects the position coordinates of the vehicle using the GPS information and the position correction information, and outputs the coordinates to the information processing unit 22.
[0028]
Here, the azimuth angle refers to an angle between a geographical direction line toward the North Pole and a traveling direction line of the train 2. The azimuth detecting unit 28 has a geomagnetic sensor (not shown). The geomagnetic sensor is one of magnetic sensors that measure the strength of the earth's magnetic field. As the geomagnetic sensor, a search coil type magnetic sensor, a Hall element type magnetic sensor, a magnetic modulator type magnetic sensor, or the like is used. These geomagnetic sensors detect the direction of the north pole (magnetic north pole) of the earth's magnetic field.
[0029]
As one of the magnetic modulator type magnetic sensors described above, a flux gate type magnetic sensor is used. The flux-gate type magnetic sensor uses an AC drive coil wound around a core made of a material with high magnetic permeability to magnetically saturate the core, and generates an external magnetic field from the output voltage appearing on other magnetic field detection coils wound around the core. It is a sensor to detect. By providing two sets of magnetic field detection coils (x direction magnetic field detection coil and y direction magnetic field detection coil) and arranging the x direction magnetic field detection coil and the y direction magnetic field detection coil perpendicular to each other, the x direction component of the external magnetic field And y-direction components can be detected.
[0030]
By utilizing this principle, the direction of the north pole (magnetic north pole) of the earth's magnetic field can be detected. Since the positional relationship between the magnetic North Pole and the geographic North Pole is known, the direction to the Magnetic North Pole is determined to detect the azimuth angle, which is the angle between the geographic North Pole direction and the train 2 travel direction line. can do. When the azimuth detecting unit 28 has another type of geomagnetic sensor, the principle is different, but the direction of the magnetic north pole can be detected, and the azimuth of the train 2 can be detected based on this. Has become. An output indicating the azimuth detected by the azimuth detection unit 28 is sent to the information processing unit 22.
[0031]
In addition, the axle rotation speed detection unit 29 has a speed generator (not shown). The speed generator is a device attached to the axle 21a of the train 2, and generates pulses (for example, ν pulses per rotation; ν: a positive integer) according to the rotation speed of the axle 21a. With this pulse, the rotation speed of the axle 21a is detected. The output indicating the axle rotation speed is sent to the information processing unit 22.
[0032]
The information processing unit 22 is a unit that processes and analyzes the GPS information and the position correction information sent from the GPS processing unit 26. Although not shown, the information processing unit 22 includes a CPU (Central Processing Unit), a RAM, a data / command input unit, an image display unit, an output unit, and the like.
[0033]
Although not shown, the CPU performs four arithmetic operations (addition, subtraction, multiplication, and division) on various data, or performs logical operations (logical product, logical sum, negation, exclusive logical sum, and the like). It is a part that performs processing such as data comparison or data shift.
[0034]
Although not shown, the information storage unit 23 includes a hard disk drive (HDD), a ROM (Read Only Memory), and the like, and includes a control program for controlling the CPU and various types of information used by the CPU. This part stores data and the like. Further, the ROM is generally constituted by a semiconductor chip or the like.
[0035]
Although not shown, the information processing unit 22 includes a RAM (Random Access Memory: random access memory). The RAM is a part for temporarily storing data and the like calculated by the CPU. The RAM is generally constituted by a semiconductor chip or the like.
[0036]
Although not shown, the information processing unit 22 includes a data / input unit such as a keyboard, various keys and switches, and an image display unit such as a CRT (Cathode Ray Tube) monitor or a liquid crystal display panel. have. The information processing unit 22 has an output unit (not shown). The output unit has a printer, an external output terminal, a communication device such as a modem, a LAN (Local Area Network) port, and the like, and prints a calculation result of the CPU and processed data on paper or the like, or outputs an electric signal. It is a part that is output or transmitted to the outside. If an external recording device such as a flexible disk (FD) device, a magneto-optical disk device such as an MO or CD-RW, or an IC card device is connected to the external output terminal, data to be set and processing by the CPU are performed. Result data and the like can be recorded on a recording medium such as a disk and taken out.
[0037]
Further, although not shown, the GPS processing unit 26 in the train vehicle position detection system 100 of the present embodiment also has a CPU, RAM, ROM, data / command input unit, It has an output unit and the like.
[0038]
The information processing unit 22 detects the axle rotation speed from the output sent from the axle rotation speed detection unit 29. Further, the information processing unit 22 calculates the rotation speed of the axle from the number of axle rotations per unit time. The information processing unit 22 calculates the traveling speed of the train 2 from the calculated rotation speed of the axle and the known value of the diameter of the wheel 21.
[0039]
For example, when the axle rotation speed per unit time is N (times / second), the axle angular speed ω is ω = 2πN (radians / second). Here, π indicates the pi. In this case, assuming that the diameter of the wheels 21 of the train 2 is D (meters), the speed V at the outer periphery of the wheels 21 _O Is V _O = (D / 2) × ω = πND (meters / second). Since there is no slippage between the wheel 21 and the rail 11, the traveling speed of the train 2 is equal to the speed V _O Becomes equal to
[0040]
The information processing unit 22 integrates the number of pulses from the axle rotation speed detection unit 29. For example, when the diameter of the wheels 21 of the train 2 is D (meters), the length of the outer circumference (circumference) of the wheels 21 is πD (meters). When the axle rotation number detecting unit 29 generates ν pulses in one rotation of the axle, the information processing unit 22 outputs πMD / ν (meters) when the number of integrated pulses is M. ) Is calculated, it is assumed that there is no slippage between the wheel 21 and the rail 11, and the value of πMD / ν (meter) is output as the travel distance of the train 2. Further, the information processing unit 22 uses the calculated moving distance to calculate a distance from the starting point (distance: zero) to the point or a distance from an intermediate point where the distance is known to the point. . Here, the “distance” is not a linear distance but a length traveled along the railway line 1, and is a value corresponding to a so-called “distance”. Further, the above-described respective calculation results are stored in the information storage unit 23, the RAM in the information processing unit 22, or the like. The distance calculated from the rotation of the axle as described above is hereinafter referred to as “axle distance”.
[0041]
Next, the operation performed by the train vehicle position detection system 100 will be described in more detail with reference to FIGS.
[0042]
Prior to the description of the operation performed by the train vehicle position detection system 100, the configuration and operation of the DGPS will be described.
[0043]
The GPS satellite G1 and the like are artificial satellites orbiting the earth at about 20,000 km above the earth. The orbit has six different orbits, each of which is shifted 60 degrees in longitude across the equatorial plane of the earth. The total number of GPS satellites is 24, and four GPS satellites are arranged in each orbit. With such a configuration, at any point on the earth, four or more GPS satellites can be seen.
[0044]
Radio signals for positioning are transmitted from the respective GPS satellites G1 and the like. This radio signal is a digital signal, and the digital signal includes a positioning code repeated every predetermined period (for example, 1 millisecond), orbit information of a transmitted GPS satellite, and the like. This positioning code is also generated inside the GPS processing unit 26. For this reason, if the time of the clock mounted on the GPS satellite G1 or the like and the time of the clock on the receiving side (for example, the GPS processing unit 26) match without error, the time lag of the positioning code (hereinafter, referred to as the time) By detecting “time difference”, the distance between the received GPS satellite and the position of the received device (hereinafter, referred to as “pseudo distance”) can be calculated.
[0045]
That is, the pseudo distance from the reception position of the radio wave from the GPS satellite to a certain GPS satellite can be obtained by multiplying the above time difference by the speed (light speed) of the radio wave. The three-dimensional position coordinates of the GPS satellite at each time can be calculated from the orbit information in the above digital signal. If the three-dimensional position coordinates of a certain GPS satellite at a certain time are (α, β, γ), the three-dimensional position coordinates of the GPS radio wave reception position are (x, y, z), and the pseudo distance at that time is R, , The following equation (1) holds.
(X-α) ² + (Y-β) ² + (Z-γ) ² = R ² ……… (1)
[0046]
Since the number of variables of the three-dimensional position coordinates (x, y, z) of the GPS radio wave reception position is three, radio waves from three different GPS satellites are simultaneously received and the pseudo distance is calculated. By obtaining three relational expressions similar to 1) and solving them, the values of x, y, and z can be obtained. However, since there is a time error between the clock of the GPS satellite and the clock of the receiving device, the calculated pseudo distance R includes an error ΔR. Therefore, in the above method, the values of x, y, and z cannot be uniquely determined.
[0047]
In order to solve this, if radio waves from at least four different GPS satellites are received at the same time and the pseudo distance is calculated, and at least four relational expressions similar to the above expression (1) are obtained, ΔR is considered. Meanwhile, the values of x, y, and z can be uniquely determined. The GPS processing unit 26 in the train vehicle position detection system 100 of the present embodiment is configured to output the received number n of GPS satellites to the information processing unit 22.
[0048]
Even if four or more GPS satellites are captured and their radio signals are obtained, the positioning accuracy is rather reduced depending on the relative arrangement of the GPS satellites. This is due to geometric properties. For this reason, the accuracy in such a case is referred to as a geometric accuracy reduction rate (hereinafter, referred to as “GDOP”).
[0049]
The smaller the value of GDOP, the higher the accuracy. For example, the value of GDOP decreases as the relative angle formed between the GPS radio signal receiving position and the line connecting each GPS satellite increases. Therefore, the larger the volume of a tetrahedron created by connecting four GPS satellites, the smaller the GDOP value. For this reason, when five or more GPS satellites are captured, the GPS processing unit 26 selects a combination of four GPS satellites that minimizes the GDOP value, and adopts this combination for positioning calculation. I have to.
[0050]
The above GDOP is expressed by the following equation (2).
GDOP ² = PDOP ² + TDOP ² ............ (2)
[0051]
In the above equation (2), PDOP indicates a rate of decrease in position accuracy at an observation point on the earth (Position Dilution of Precision: hereinafter, referred to as “rate of decrease in position accuracy”), and TDOP indicates a decrease in time accuracy. Rate (Time Dilution of Precision: hereinafter, referred to as “time precision reduction rate”).
[0052]
PDOP is represented by the following equation (3).
PDOP ² = HDOP ² + VDOP ² ……… (3)
[0053]
In the above equation (3), HDOP represents a horizontal direction of precision (hereinafter referred to as “horizontal position accuracy reduction rate”) at an observation point on the earth, and VDOP. Indicates a vertical direction of precision (hereinafter referred to as “vertical direction accuracy reduction rate”) at a vertical position at an observation point on the earth.
[0054]
The GPS processing unit 26 in the train vehicle position detection system 100 according to the present embodiment is configured to output the HDOP value calculated using a predetermined proportional constant to the information processing unit 22.
[0055]
The above description relates to the general configuration and operation of a GPS (Global Positioning System). A radio signal from a normal GPS satellite includes a radio wave delay due to the influence of the ionosphere and the convection layer, a clock error on the GPS receiver side, and a clock error in the GPS satellite. Therefore, due to these effects, the positioning result also includes an error. DGPS aims to reduce such errors and increase the accuracy of the positioning result.
[0056]
In the DGPS, in addition to the GPS satellite and the receiving device, the above-described positioning by GPS (single positioning) is performed at a reference position where accurate position data (latitude, longitude, height on the earth ellipsoid) is measured by surveying or the like. Do. Thereby, both the known position data of the reference position (reference position data) and the position data by GPS at that time (GPS position data) are obtained. The difference between the reference position data and the GPS position data can be used as a correction amount at another position.
[0057]
Therefore, if the data of the difference between the reference position data and the GPS position data is calculated in real time and transmitted by radio waves as position correction information, at other places where the position correction information is received, the GPS alone performs positioning. By performing correction by subtracting from the calculated position coordinates by the correction amount shown in the position correction information, more accurate three-dimensional position coordinates are calculated, and these three-dimensional position coordinates are converted into latitude and longitude on the earth The position coordinates (hereinafter, referred to as “DGPS position coordinates”) can be obtained. Such a system is DGPS. In the train vehicle position detection system 100 of the present embodiment, the position of the reference position station 3 is known, and the reference position station 3 transmits position correction information in real time. Here, the DGPS position coordinates correspond to the GPS position coordinates in the claims.
[0058]
In DGPS, it is ideal to use the position correction information from the reference position station for the correction of the GPS positioning position at the same time, but actually, the position correction information from the reference position station is used for a certain time. Will be used for correcting the GPS positioning position at the time point when. However, since the GPS satellites are moving every moment, an error is included in the position correction information as time passes. When the time at which other parts are corrected based on the transmission time of the position correction information from the reference position station is referred to as “delay time” and is represented by τ, the error of the position correction information is τ ² Is known to be proportional to The GPS processing unit 26 in the train-owned-vehicle position detection system 100 according to the present embodiment uses the time difference between the latest time at which the position correction information is received and the time of the data to be corrected as a differential correction data update time t as information processing. It is configured to output to the unit 22.
[0059]
Further, the information processing section 22 can obtain the distance from the DGPS position coordinates (latitude, longitude). That is, if the distance between two points on the track is sufficiently small, the straight line distance between the two points is equal to the distance. Therefore, the distance is calculated by using the distance, and the distance is calculated by adding them. can do. The distance obtained from the DGPS position coordinates in this manner is hereinafter referred to as “DGPS distance”.
[0060]
Next, the operation of the train vehicle position detection system 100 of the present embodiment including the above-described DGPS will be described in more detail.
[0061]
First, in order to create a database of track information, as shown in FIG. 1, a train 2 travels for information measurement on the railroad track 1. In FIG. 1, a railroad track 1 is installed in the left-right direction in the figure, and a train 2 is illustrated as traveling from left to right in the figure.
[0062]
In this information measurement run, the information processing unit 22 calculates the “correspondence to track curvature” at each position of the running section at each time from the train running speed obtained from the axle rotation speed at each time and the azimuth at each time. Value ”. Also, the axle distance at that time is calculated.
[0063]
Hereinafter, the line curvature equivalent value will be described with reference to FIG. As shown in FIG. 2A, consider a point A on the track and a point B on the track separated from the point A by a very small distance. In this case, the curve AB can be regarded as an arc, and assuming that the radius of curvature is R (unit: meter), the center of the circle is O and the center angle of the arc AB is a minute angle Δθ (unit: radian). , The length L of the arc AB _AB (Unit: meter) can be calculated by R × Δθ. Therefore, Δθ is (L _AB / R).
[0064]
Further, as shown in FIG. 2B, the azimuth at the point A is represented by θ in units of radians. _A And the azimuth at point B is expressed in radians as θ _B Then, the change amount of the azimuth angle when moving from the point A to the point B (θ _B −θ _A ) Is equal to Δθ. The value (Δθ / ΔT) obtained by dividing the azimuth angle change Δθ by the elapsed time ΔT (unit: second) is hereinafter referred to as “azimuth angle change rate” θ ′. This azimuth angle change rate θ ′, that is, (Δθ / ΔT) is calculated based on the relationship of FIG. _AB / ΔT) × (1 / R).
[0065]
Here, (L _AB / ΔT) is the train traveling speed v (unit: meters / second) when moving on the route of the curve AB. Also, (1 / R) is the reciprocal of the radius of curvature R, and if this is defined as "corresponding value of line curvature", the equivalent value (1 / R) of line curvature is obtained by the following equation (4).
1 / R = θ '/ v (4)
[0066]
In this way, for each point (hereinafter, referred to as "pointer") of the measured distance (for example, 1 meter) on the track, the axle distance and the track curvature equivalent value (1 / R : Hereafter referred to as “corresponding value of known track curvature”). A data table in which the pointer, the distance, and the known track curvature equivalent value are associated with each other is hereinafter referred to as a “curvature equivalent value map table”. In the curvature equivalent value map table, a line segment code is also stored. The line section code is a code for specifying each line section of the railway, and different codes are assigned to the up line and the down line even for the same line section.
[0067]
Further, DGPS position coordinates (latitude value, longitude value) can be obtained at each pointer for each traveling distance of 1 meter. The CPU (not shown) of the information processing unit 22 calculates the pointer and the latitude from these data. A data table in which only data is arranged (hereinafter, referred to as “latitude index”) and a data table in which only pointers and longitude data are arranged (hereinafter, referred to as “longitude index”) are created, and these are stored in the above-mentioned line information database. Incorporate in.
[0068]
Next, the track information database created as described above is mounted on the train 2, and operation is performed. Here, it is assumed that the created track information database is subsequently stored in the information storage unit 23 of the train 2. In the operation traveling of the train 2, a CPU (not shown) in the information processing unit 22 calculates a reception reliability coefficient from the GPS information and the position correction information input from the GPS processing unit 26 at that time. . The reception reliability coefficient is a value representing the reception reliability which is the degree of reliability of the GPS information and the position correction information.
[0069]
When the reception reliability coefficient is represented by c, the reception reliability coefficient c is represented by the following equation (5). c = {f (n) + g (HDOP)} × h (t) (5)
In this case, the larger the value of c, the higher the reliability of reception.
[0070]
In the above equation (5), the first term, f (n), indicates a function of the number n of GPS satellites used for receiving GPS information. The value of f (n) is zero when the value of n is between zero and three. When the value of n is 4 or more, the value of f (n) is equal to n. That is, when the value of n is 4, the value of f (n) is 4, and when the value of n is 5, the value of f (n) is 5. The following is the same.
[0071]
As described above, in order to obtain the DGPS position coordinates at the reception position in the DGPS, at least four GPS satellites are required as in the case of general positioning of a general GPS. Therefore, when n is 3 or less, the degree of reliability of the positioning is the lowest, so that it is set to zero. If n is 4 or more, a combination (4) of GPS satellites can be selected so that GDOP (or HDOP) becomes the best, and a more accurate combination can be selected as the value of n increases. Therefore, the degree of reliability of positioning increases. In order to express this property, when n is 4 or more, f (n) = n.
[0072]
The function of f (n) may be other than the above. For example, when n is 3 or less, a fixed value k other than zero may be set. In this case, when n is 4 or more, f (n) = n ² It may be + k. Alternatively, when n is 3 or less, a fixed value k other than zero is set. When n is 4 or more, f (n) = n ^a It may be + k. In this case, a is an integer of 1 or more. Alternatively, when n is 3 or less, a fixed value k other than zero may be set, and when n is 4 or more, f (n) = f1 (n) + k. In this case, f1 (n) is a function that increases as n increases. In short, the function f (n) is a constant value k when n is 3 or less, and any function that increases from k when n is 4 or more. There may be.
[0073]
In the above equation (5), g (HDOP), which is the second term, indicates a function of the horizontal position accuracy decrease rate HDOP. If HDOP is represented as p for simplicity, g (p) is a function whose value increases as p decreases. For example, g (p) may be a function inversely proportional to p, and g (p) = 1 / p. Alternatively, g (p) is p ² G (p) = 1 / p ² It may be. In general, g (p) is p ^b G (p) = 1 / p ^b It may be. In this case, b is an integer of 1 or more.
[0074]
As described above, in the DGPS, in order to increase the horizontal position accuracy at the reception position, the smaller the value of the horizontal position accuracy reduction rate HDOP is, the more advantageous it is. For this reason, g (p) is set to be a function having a larger value as the HDOP is smaller.
[0075]
Note that the function of g (p) may be other than the above. For example, in general, g (p) is p ^b G (p) = 1 / (p + e), which is inversely proportional to and has an intercept when b is zero ^b It may be. In this case, b is an integer of 1 or more, and e is a positive real number. In short, the function g (HDOP) may be any function as long as the smaller the HDOP, the larger the value.
[0076]
In the above equation (5), h (t), which is the third term, represents a function of the differential correction data update time t. h (t) is t ² Becomes larger, the value becomes smaller, and the function has an intercept when t is zero. For example, h (t) is given by h (t) = 1 / (t ² + Q) ^r It may be. In this case, q is a positive real number, and r is an integer of 1 or more.
[0077]
As described above, in the DGPS, in order to increase the position accuracy at the reception position, it is more advantageous as the value of the differential correction data update time t is smaller. Also, t ² The error increases in proportion to the value of. Therefore, h (t) becomes t ² The function is set so that the smaller the is, the larger the function becomes.
[0078]
Note that the function of h (t) may be other than the above. In short, the function h (t) is t ² Any function may be used as long as the function is such that the smaller the value, the larger the value.
[0079]
Note that the reception reliability coefficient c is not limited to the function of the above equation (5). In general, if the function has at least one of the first term f (n), the second term g (HDOP), and the third term h (t) in the above equation (5), Any function may be used. For example, it may be the sum of the first term f (n), the second term g (HDOP), and the third term h (t). Alternatively, it may be obtained by multiplying the first term f (n), the second term g (HDOP) and the third term h (t). Alternatively, it may be a function obtained by multiplying the sum of the first term f (n) and the third term h (t) by the second term g (HDOP). Alternatively, it may be a function obtained by multiplying the sum of the second term g (HDOP) and the third term h (t) by the first term f (n). Alternatively, it may be a function obtained by multiplying any two terms and adding the remaining one term.
[0080]
Next, a CPU (not shown) in the information processing unit 22 compares the calculated value of the reception reliability coefficient c with a determination value stored in the information storage unit 23 in advance. As the discrimination values, for example, two real numbers s1 satisfying s1 <s2 (hereinafter, referred to as “first discrimination value”) and s2 (hereinafter, referred to as “second discrimination value”) are used.
[0081]
In this case, if the calculated reception reliability coefficient c is larger than the second determination value s2, that is, if s2 <c, the CPU (not shown) in the information processing unit 22 determines the reliability of the DGPS reception. The degree is determined to be “high”. In this case, the CPU (not shown) in the information processing unit 22 specifies the current position (for example, the distance) of the train in this traveling section based on the DGPS position coordinates. This is because if the reliability of the data from the DGPS is high, it is considered that specifying the position using only the DGPS data has higher accuracy.
[0082]
When the calculated reception reliability coefficient c is equal to or greater than the first determination value s1 and equal to or less than the second determination value s2, that is, when s1 ≦ c ≦ s2, the DGPS reception reliability is “medium”. Degree ”. In this case, the CPU (not shown) in the information processing unit 22 sets the DGPS distance obtained from the DGPS position coordinates as an initial value, and obtains the azimuth at each time point during operation and the axle rotation speed. The current position of the train in the running section is specified by calculating the equivalent value of the track curvature during operation running from the train running speed and comparing it with the known equivalent value of the track curvature. This is because if the reliability of the data from the DGPS is not so high, it is better to add the azimuth data to specify the position as much as the DGPS distance obtained from the DGPS than to the method using only the DGPS data. This is because the accuracy is considered to be high.
[0083]
When the calculated reception reliability coefficient c is smaller than the first determination value s1, that is, when c <s1, it is determined that the DGPS reception reliability is “low”. In this case, the CPU (not shown) in the information processing unit 22 specifies the current position of the train in the traveling section based on the axle distance based on the axle rotation speed. This is because if the reliability of the data from the DGPS is low, DGPS data is not used, and specifying the position based on the axle distance, which is the distance based on the axle rotation speed, is more accurate. Because it is possible.
[0084]
Next, the first of the above three methods for specifying the current position of the vehicle, that is, the method for specifying the current position (distance) of the train in the traveling section based on the DGPS position coordinates will be described in further detail. .
[0085]
In FIG. 3, reference numeral 1 indicates a planar shape of the railway line. In this case, it is assumed that the train is traveling upward from below in FIG. At this time, it is assumed that DGPS position coordinates (latitude λ, longitude μ) have been obtained. Further, it is assumed that this position is a point C which is not a point on the railway line 1 in FIG. The process so far is hereinafter referred to as “first step”.
[0086]
In this case, the CPU (not shown) of the information processing section 22 sets n pointers having a latitude smaller than the latitude λ from the above-mentioned latitude index so that A total of 2n pointers are selected, with n pointers having a larger latitude. The process so far is hereinafter referred to as “second step”.
[0087]
Also, the CPU (not shown) of the information processing section 22 sets the longitude μ to be included in the middle of the above-mentioned longitude index, and sets n pointers having a longitude smaller than the longitude μ, Also, n pointers having a large longitude are selected, that is, a total of 2n pointers are selected. The process so far is hereinafter referred to as “third step”.
[0088]
Next, the CPU (not shown) of the information processing unit 22 selects only a matching (identical) pointer from the pointers selected as described above. Next, the CPU (not shown) of the information processing unit 22 calculates the distance between these pointers and the point C.
[0089]
For example, the DGPS position coordinates of the point C are converted into an xy coordinate system based on a certain position to calculate (x1, y1), and the DGPS position coordinates of the pointer for which the distance is to be calculated are calculated in the xy coordinate system. And calculating (x2, y2), the distance L between the point C and the two points of this pointer can be calculated by the following equation (6).
L = ｛(x2-x1) ² + (Y2-y1) ² ｝ ^1/2 ............ (6)
[0090]
After the distance L between the point C and each pointer is obtained in this manner, two points are selected: a point (pointer) where the distance L is the minimum, and a point (pointer) where the distance L is next smaller. FIG. 3 shows point A and point B as these two points (pointers). In this case, the distance of the point B is larger than the distance of the point A. The process up to this point is hereinafter referred to as “fourth step”.
[0091]
In FIG. 3, the distance between points A and C is a, the distance between points C and B is b, and the distance between points A and B is c. In this case, assuming that a point at which a perpendicular line drawn from the point C to the line segment AB intersects the line segment P is P, the distance d between the point A and the point P can be calculated by the following equation (7). The process so far is hereinafter referred to as “fifth step”.
d = (a ² -B ² + C ² ) / 2c ............ (7)
[0092]
The CPU (not shown) of the information processing section 22 outputs the distance obtained by adding the value d calculated by the above equation (7) to the distance of the point A as the distance at the current time, and stores the information. It is stored in the unit 23. The process up to this point is hereinafter referred to as “sixth step”.
[0093]
In the above description, the position of the point C corresponds to the first position in the claims, the position of the point A corresponds to the second position in the claims, and the position of the point B corresponds to the position in the claims. This corresponds to the third position. Alternatively, the position of point A may be the third position in the claims, and the position of point A may be the second position in the claims.
[0094]
In the fourth step of the above-described method, the distance between each of the selected pointers and the point C is calculated, and the point having the smallest distance (pointer) and the point having the next smaller distance (pointer) are calculated. When two points are selected, the line segment code is also determined, and a predetermined process is performed according to the line segment code. That is, when the line segment code of each selected pointer is the same as the line segment code of the track on which the train is currently running, the above-described method is applied as it is.
[0095]
However, if any of the selected pointers has a line segment code different from the line segment code of the track on which the train is currently traveling, the distance to the point C is calculated after the distance to the point C is calculated. A predetermined penalty value m is added to the distance value. The value of m is a large value such as m = 20 meters when the distance between pointers is 1 meter. This is to prevent the distance of another branching line and the distance of the main line from being confused at a branching point or the like.
[0096]
Next, the second method of the three vehicle current position specifying methods described above, that is, the DGPS distance obtained from the DGPS position coordinates is used as the initial value, and the azimuth and the axle at each time point during operation driving are calculated. A train curvature equivalent value during operation (hereinafter, referred to as “operating line curvature equivalent value”) is calculated from the train traveling speed obtained from the rotation speed, and is compared with the known line curvature equivalent value in the above-mentioned line information database. By doing so, a method for specifying the current position of the train in the traveling section will be described in more detail.
[0097]
In this method, first, a DGPS distance obtained from DGPS position coordinates is set as an initial value. This is because the reliability of the DGPS data is not high, but is moderate, and the DGPS distance is more reliable as an initial value than the axle distance obtained from the axle rotation speed. This is because
[0098]
Next, a comparison is made between the operating line curvature equivalent value calculated during operation traveling and the known line curvature equivalent value. This method will be described in detail with reference to FIG.
[0099]
First, in the current operation traveling, the CPU (not shown) of the information processing unit 22 calculates a curvature equivalent value from the train traveling speed v obtained from the axle rotation speed and the azimuth change rate θ ′ by the above equation (4). Calculate 1 / R.
[0100]
Next, the CPU (not shown) of the information processing section 22 compares the equivalent value of the line curvature during the current operation and the equivalent value of the known line curvature in the equivalent curvature map table. In this case, first, a deviation coefficient is calculated for the current line curvature equivalent value during operation and the data of the known line curvature equivalent value in the line information database.
[0101]
This deviation coefficient is calculated as follows. That is, first, from the known curvature equivalent value data, a section including the initial value of the distance, for example, the distance K in the curvature equivalent value map table is included. ₁ To K ₂ Select the section up to. It is assumed that this section includes i (i: an integer of 2 or more) continuous pointers. The known curvature equivalent value data of these pointers are arranged in order from the curvature equivalent value data of the smallest pointer about the distance to the curvature equivalent value data of the largest pointer about the distance, and δ ₁ 1, δ ₂ ,…, Δ _i Assume that
[0102]
Next, the i corresponding curvature equivalent value data immediately before being sampled at a constant distance during the current operation traveling is calculated from the curvature equivalent value data of the smallest pointer of the distance to the curvature equivalent value data of the largest pointer of the distance. Up to 順 に ₁ 1, ξ ₂ ,…, Ξ _i Assume that
[0103]
Next, using the known curvature equivalent value data and the current curvature equivalent value data, the square value of the difference between the corresponding data values, for example, (δ ₁ −ξ ₁ ) ² , (Δ ₂ −ξ ₂ ) ² ,…, (Δ _i −ξ _i ) ² Ask for. Since the number of pointers is i, i square values are obtained. Next, the sum of these i square values is calculated. This is a deviation coefficient, and when this is w, the deviation coefficient w can be calculated by the following equation (8).
w = Σ (δ _k −ξ _k ) ² ............ (8)
[0104]
The CPU (not shown) of the information processing section 22 increases or decreases the distance of the section selected from the known curvature equivalent value data by, for example, one pointer or one pointer. Calculate the deviation coefficient for the case. As a result, when the section where the deviation coefficient is the smallest is found, the moving amount (the amount indicating how many pointers are shifted from the initial value of the distance) in that case is obtained, and the initial value of the distance is calculated by the corresponding value. And the distance at the time of comparison.
[0105]
The above processing will be described with reference to the graph of FIG. FIG. 4A is a graph illustrating a set S1 of known line curvature equivalent value data extracted for comparison between the known line curvature equivalent value and the operating line curvature equivalent value in relation to the traveling distance. The horizontal axis is the running distance (unit: 10) ⁴ Meters), and the vertical axis indicates a line curvature equivalent value (unit: 1 / meter). The cut-out known line curvature equivalent value data set S1 is the distance value initial value K in the above description. _c Known curve curvature equivalent value data δ corresponding to _c , And the number of data is j (an integer satisfying j: j> i) which is several times larger than i. In FIG. 4A, the entire known line curvature equivalent value is indicated by a solid line for easy recognition, and the known curvature equivalent value data set S1 cut out therefrom is indicated by a thick solid line.
[0106]
Next, FIG. 4B shows i data sets S2 of the operation-time track curvature equivalent value data during the current operation run, for example, ξ in the above description. ₁ 1, ξ ₂ ,…, Ξ _i Is a graph illustrating the relationship with the traveling distance, where the horizontal axis represents the traveling distance (unit: 10). ⁴ Meters), and the vertical axis indicates a line curvature equivalent value (unit: 1 / meter). In FIG. 4 (B), the line curvature equivalent value data set S2 during operation is shown by a thick solid line for easy recognition.
[0107]
Next, FIG. 4 (C) shows the data set S1 of the known line curvature equivalent value cut out in FIG. 4 (A) described above and the i-th data set in the operational line curvature equivalent value data of FIG. 4 (B). S2 is shown at the same time, and the horizontal axis represents the traveling distance (unit: 10). ⁴ Meters), and the vertical axis indicates a line curvature equivalent value (unit: 1 / meter). In FIG. 4 (C), the entire known line curvature equivalent value is indicated by a solid line, and the known curvature equivalent value data set S1 cut out therefrom is indicated by a thick solid line so as to be easily recognized. The value data set S2 is illustrated by a thick solid line.
[0108]
The waveforms of the data set S1 and the data set S2 substantially overlap each other if they are moved by a distance U in a direction from left to right in FIG. At this time, since the waveforms substantially overlap, as described above, the value of the deviation coefficient w calculated based on the two data becomes minimum (for example, substantially zero). In FIG. 4C, the set S1 (the set of data corresponding to the curvature of the line during operation) is moved by the correction amount U in the direction from left to right (in the direction in which the distance increases) in the figure. (The data set of the equivalent values of the curvature of the known track) and the distance K at the time of comparison in the current operation run is almost equal to the initial value K. _c The distance obtained by adding the distance U to the above is the distance output by the CPU (not shown) of the information processing section 22 at the time of this comparison.
[0109]
As the third method among the three methods of specifying the current position of the vehicle, two methods can be adopted. One of the methods is to calculate the distance distance at the current time by adding the distance distance specified at the previous time as an initial value and adding the axle distance value obtained from the axle rotation speed to this value. It is.
[0110]
Further, another method of the third method of the own vehicle current position specifying method will be described below. First, an axle distance obtained from the axle rotation speed is set as an initial value. Then, in the subsequent process, that is, the azimuth at each point of time during operation and the train running speed obtained from the axle rotation speed, the line curvature equivalent value during operation, which is the line curvature equivalent value during operation, is calculated, The current position of the train in the traveling section is identified by comparing the current position with the equivalent value of the known track curvature. This process is exactly the same as in the above-described second method.
[0111]
Next, other functions of the train vehicle position detection system 100 of the present embodiment will be described. The train vehicle position detection system 100 of the present embodiment has a function of automatically correcting the value of the wheel diameter D when calculating the axle distance.
[0112]
When the reception reliability is determined to be high, for example, as described above, when the reception reliability coefficient c is larger than the second determination value s2, that is, when s2 <c, Driving distance L calculated by DGPS position coordinates _G And travel distance L calculated from axle rotation speed _W And the ratio L _G / L _W Is calculated.
[0113]
The above ratio L _G / L _W If the value of (hereinafter, referred to as R) is 1, no correction is performed. Otherwise, the travel distance L calculated from the DGPS position coordinates _G Is correct, the value D of the diameter of the wheel 21 is corrected.
[0114]
For example, if the value of the ratio R is greater than 1, the traveling distance L calculated from the axle rotation speed is used. _W Indicates that the wheel diameter value D used in the current calculation is smaller than the correct value. For this reason, the information processing unit 22 performs correction so as to increase the value of the wheel diameter value D stored in the information storage unit 23. As a correction method, the stored value D at that time is multiplied by the correction rate E. This correction rate E1 is represented by the following equation (9).
E1 = 1 + (R-1) × J1 (9)
[0115]
In this case, the value of the ratio R is larger than 1, for example, about 1.1, so that (R-1) in the above equation (9) is a small positive value, for example, 0.1. It becomes such a value. J1 in the above equation (9) is a small positive value, for example, a value such as 0.05 or 0.1.
[0116]
The reason for multiplying (R-1) by the small value of J1 as described above is as follows. If the value of the ratio R is 1.1 and the wheel diameter value D at that time is directly multiplied by 1.1, the change in the axle distance may be too large. Therefore, in order to gradually increase the wheel diameter value, the wheel diameter is multiplied by J1 which is a small value corresponding to 1/20 or 1/10 of the value of (R-1). If the degree of increase in the wheel diameter value is not enough, the ratio R will be greater than 1 even at the next time point, so that the correction rate E1 for the new increase may be multiplied again.
[0117]
If the value of the ratio R is smaller than 1, the travel distance L calculated from the axle rotation speed is used. _W Indicates that the value of the wheel diameter value D used in the current calculation is larger than the correct value. For this reason, the information processing unit 22 performs correction so as to decrease the value of the wheel diameter value D stored in the information storage unit 23. As a correction method, the stored value D at that time is multiplied by the correction rate E2. This correction rate E2 is represented by the following equation (10).
E2 = 1− (1−R) × J2 (10)
[0118]
In this case, the value of the ratio R is a value smaller than 1, for example, a value of about 0.9. Therefore, (1-R) in the above equation (10) is a small positive value, for example, 0.1. It becomes such a value. J2 in the above equation (10) is a small positive value, for example, a value such as 0.05 or 0.1.
[0119]
As described above, the reason for multiplying (1-R) by the small value of J2 is exactly the same as in the case of J1 described above.
[0120]
As described above, the use of the train vehicle position detection system 100 of the present embodiment makes it possible to detect the distance of a train using only a GPS satellite, a reference position station, and a train-mounted device. The ground child etc. becomes unnecessary. For this reason, there is an advantage that even if the ATS ground element is moved from the initial position to another position, the own vehicle position can be detected without any trouble.
[0121]
Note that the present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the claims of the present invention, and any device having the same operation and effect can be realized by the present invention. It is included in the technical scope of the invention.
[0122]
For example, in the above-described embodiment, the GPS receiving means receives GPS information transmitted by radio waves from GPS satellites and position correction information transmitted by radio waves from the reference position station, and based on the GPS information and the position correction information. Although the means for calculating the DGPS position coordinates has been described as an example, the present invention is not limited to this. For example, the GPS receiving means of another configuration, for example, receiving only GPS information without using position correction information Alternatively, means for calculating position coordinates (GPS position coordinates) based on GPS information may be used.
[0123]
In this case, the reception reliability coefficient can be a function that does not include the function h (t) of the differential correction data update time t described above. For example, the following c1, c2, c3 and the like can be mentioned.
c1 = f (n)
c2 = g (HDOP)
c3 = f (n) + g (HDOP)
[0124]
In the case of a general GPS other than the DGPS, the reception reliability coefficient includes a function h (t) of the differential correction data update time t, but a very large numerical value close to infinity is used as the value of t. It can be used. Even in this case, the effect of the function h (t) of the differential correction data update time t can be made substantially zero.
[0125]
Further, in the above embodiment, as the axle rotation speed detecting means, the one having a speed generator attached to the axle of the train has been described as an example, but the present invention is not limited to this, and other configurations are provided. For example, when the train is an electric car, a speed generator may be attached to the rotating shaft of the main motor. When the train is a railcar, a speed generator may be attached to the rotating shaft of the prime mover.
[0126]
Further, in the above-described embodiment, the description has been given by taking the railroad train as an example. However, the present invention can be applied to other transportation systems, for example, a new transportation system, a monorail, and the like.
[0127]
The information storage unit 23 includes a flexible disk (FD) device, a magneto-optical disk device such as an MO or a CD-RW, and an IC card device, in addition to the above-described configuration, and records information by loading the device. Or a disk (recording medium) for reading or reading. In this case, the above-mentioned line information database (a database for associating the distance and the known track curvature equivalent value, which is the curvature equivalent value of the track, with the latitude and longitude, for example, the above-mentioned curvature equivalent value map table, latitude index , Longitude index, etc.) may be stored in a recording medium such as each disk, and the data in the line information database may be read from the recording medium. As described above, if the data of the track information database is recorded on the recording medium, the track information database obtained by the information measurement travel can be widely used in other trains other than the train that performed the information measurement travel. Can be convenient.
[0128]
Further, instead of the deviation coefficient w of the equation (8) in the above embodiment, a cross-correlation coefficient ρ represented by the following equations (11) to (14) is calculated, and the cross-correlation coefficient ρ is The data set S1 of the known curve curvature equivalent value thus cut out and the i data sets S2 of the circuit curvature equivalent value data during operation are shifted, and the distance obtained during operation traveling is corrected by the shifted amount of movement. You may. The cross-correlation coefficient ρ is ² ≦ 1, the value of ρ becomes substantially 1 when the cut-out known line curvature equivalent value data set S1 and the i data sets S2 of the operation-time line curvature equivalent value data substantially overlap with each other. .
[0129]
ρ = V _ab / (√V _aa × √V _bb ) …… (11)
V _aa = {1/1 / (i-1)}) × Σ ｛(δ _k -M ₁ ) ² ｝ ……… (12)
V _bb = {1 / (i-1)}) × Σ ｛(ξ _k -M ₂ ) ² ｝ ……… (13)
V _ab = {1/1 / (i-1)}) × Σ ｛(δ _k -M ₁ ) × (ξ _k -M ₂ )｝… (14)
[0130]
Equation (12) gives the average value m in the data set of δ ₁ Represents the "variance" indicating the degree of variation from. In addition, the above equation (13) gives the average value m in the data set of ξ ₂ Represents the "variance" indicating the degree of variation from. The above equation (14) represents the “covariance” in the two data sets, the data set of δ and the data set of ξ.
[0131]
In the above equations (12) to (14), Σ represents the sum total from k = 1 to k = i. Also, m ₁ Is i data δ ₁ ~ Δ _i Mean value. Also, m ₂ Is i data ξ ₁ ~ Ξ _i Mean value.
[0132]
Note that the method of searching for a substantially overlapping state while shifting the cut-out known line curvature equivalent value data set S1 and the i data set S2 of operation-time line curvature equivalent value data from each other is limited to the method of the above embodiment. Not done. Other methods may be used. For example, as the distance, the initial value K _c May be selected as the minimum value of the set of δ in a certain section as the known line curvature equivalent value data corresponding to. Alternatively, the initial value K for the distance _c May be selected as the maximum value from the set of δ in a certain section as the known line curvature equivalent value data corresponding to.
[0133]
The present invention can also use a GPS device in which the GPS processing unit 26 outputs an azimuth angle from GPS information. In this case, the azimuth detecting unit 28 in FIG. 1 is included in the GPS processing unit 26. That is, in this case, the GPS receiving means in the claims includes the azimuth detecting means in the claims.
[0134]
The line curvature equivalent value is calculated using the azimuth angle change rate, and the azimuth angle change amount (θ _B −θ _A = Δθ). When the time interval ΔT at which the azimuth is output is a constant value, for example, when the azimuth is output every one second, the azimuth change rate θ ′ (= Δθ / ΔT) Instead of using the azimuth angle change amount Δθ, the line curvature equivalent value (1 / R) can be obtained in exactly the same manner as in the case of the azimuth angle change rate θ ′.
[0135]
【The invention's effect】
As described above, according to the present invention, the GPS is applied to the train traveling system, and the azimuth angle detection means, the axle rotation speed detection means, the latitude and longitude, the equivalent value of the known track curvature, and the distance are related. Information storage means for storing a track information database to be attached, and an information processing means, wherein the information processing means calculates a reception reliability coefficient indicating the degree of reliability of the GPS information during operation of the train, and If the distance is high, the distance is specified on the basis of the GPS position coordinates. If the reception reliability is medium, the GPS distance is set as an initial value, a value corresponding to the line curvature during operation is calculated, and the known line is calculated. The distance range is specified by comparing with the curvature equivalent value, and when the reception reliability is low, the distance range is specified based on the distance range based on the axle rotation speed. Reference position And as the train distance just train mounting device can be detected, the ATS ground element and the like as in the conventional system is not required. For this reason, there is an advantage that even if the ATS ground element is moved from the initial position to another position, the own vehicle position can be detected without any trouble.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the configuration of a train vehicle position detection system according to an embodiment of the present invention.
FIG. 2 is a conceptual diagram illustrating an azimuth angle change rate in the train vehicle position detection system shown in FIG.
FIG. 3 is a first diagram illustrating the operation of the train vehicle position detection system shown in FIG. 1;
FIG. 4 is a second diagram illustrating the operation of the train vehicle position detection system shown in FIG. 1;
[Explanation of symbols]
1 railway tracks
2 train
3 Reference position station
11 rails
20 Train mounted equipment
21 wheels
21a axle
22 Information Processing Department
23 Information storage unit
24 First antenna
25 Second antenna
26 GPS processing unit
27 Differential receiver
28 Azimuth angle detector
29 Axle speed detector
31 transmitting antenna
100 Train position detection system
G1 to Gn GPS satellites
K ₁ The minimum value of the distance corresponding to the extracted known line curvature equivalent value data set
K ₂ The maximum value of the distance corresponding to the extracted data set of known curvature equivalent values
K _c Initial value for distance
S1 Data set of known curve curvature equivalent value extracted
S2 i data sets of line curvature equivalent value data during operation
U correction amount

Claims (13)

A method of detecting a current position on a track of the train using the train mounted device and a plurality of GPS satellites orbiting the earth using the train mounted device,
In the train mounted device,
GPS receiving means for receiving GPS information transmitted by radio waves from the GPS satellites and calculating GPS position coordinates based on the GPS information;
Azimuth angle detection means for detecting the azimuth angle of the vehicle body when the train is running,
Axle rotation speed detecting means for detecting the axle rotation speed of the train,
Information storage means for storing a line information database that associates the latitude and longitude, the known line curvature equivalent value that is a value corresponding to the curvature of the line, and the distance,
Providing information processing means,
The information processing means, when the train runs on the track, calculates a reception reliability coefficient representing a reception reliability which is a degree of reliability at the time of receiving the GPS information,
When the reception reliability is determined to be high, the information processing unit specifies a current position of the train in the traveling section based on the GPS position coordinates,
When the reception reliability is determined to be medium, the information processing means sets a distance value based on the GPS position coordinates as an initial value, and sets the azimuth angle and the axle rotation at each time during operation driving. By calculating the operating line curvature equivalent value that is a value corresponding to the line curvature during operation from the train traveling speed obtained from the number, and comparing it with the known line curvature equivalent value in the line information database, Identify the current position of the train in the travel section,
The train is characterized in that, when the reception reliability is determined to be low, the information processing means specifies a current position of the train in the traveling section based on a distance based on the axle rotation speed. Vehicle position detection method. The method for detecting the position of a train vehicle according to claim 1,
When the reception reliability is determined to be low, the information processing unit sets a distance based on the axle rotation speed as an initial value, and sets the azimuth angle at each time point during operation traveling and the axle rotation speed. By calculating the operating line curvature equivalent value that is a value corresponding to the line curvature during operation from the train traveling speed obtained from the number, and comparing it with the known line curvature equivalent value in the line information database, A method for detecting the position of a train vehicle, comprising identifying a current position of a train in a traveling section. The method for detecting the position of a train vehicle according to claim 1,
The GPS receiving means includes the azimuth detecting means,
The information processing means, when the reception reliability is determined to be low, identifies the current position of the train in the traveling section by a distance based on the axle rotation speed. Position detection method. The method for detecting the position of a train vehicle according to claim 1,
The information measurement travel is performed by the train, and the information processing means detects each position of a travel section based on the GPS position coordinates at each time, and travels from a reference position based on the axle rotation speed. And calculates the value corresponding to the line curvature at each position in the traveling section from the azimuth angle at each time point and the train traveling speed obtained from the axle rotation speed, and calculates the line curvature as a known line curvature equivalent value. A method for detecting a position of a train vehicle, wherein the method is stored in an information database. In the method of detecting the position of a train vehicle according to claim 4,
With a reference position station whose position is being measured,
The GPS receiving means receives GPS information transmitted by radio waves from the GPS satellites and position correction information transmitted by radio waves from the reference position station, and receives DGPS position coordinates based on the GPS information and the position correction information. Is calculated,
When the train travels on the track, the information processing means calculates a reception reliability coefficient representing a reception reliability which is a degree of reliability at the time of receiving the GPS information and the position correction information. A method for detecting the position of a train vehicle. In the method of detecting the position of a train vehicle according to claim 4,
The reception reliability coefficient is:
A first term that is a function of the number n of the GPS satellites used for receiving the GPS information, and that the larger the n is, the higher the reception reliability is;
A function of HDOP, which is a rate of decrease in horizontal position accuracy at an observation point on the earth, and has at least one of the second term expressing that the smaller the HDOP is, the higher the reception reliability is. A method for detecting the position of a train vehicle, characterized in that the function is a function constituted by: In the method of detecting the position of a train vehicle according to claim 4,
The reception reliability coefficient is:
A first term that is a function of the number n of the GPS satellites used for receiving the GPS information, and that the larger the n is, the higher the reception reliability is;
A second term that is a function of HDOP, which is a rate of decrease in horizontal position accuracy at an observation point on the earth, and that the smaller the HDOP is, the higher the reception reliability is;
This is a function of a differential correction data update time t, which is a time difference between the most recent time at which the position correction information was received and the time at which the reception reliability coefficient was calculated, and the smaller the t, the higher the reception reliability. A method of detecting the position of a train vehicle, characterized in that the function is a function configured to include at least one of the following three terms: In the method for detecting the position of a train vehicle according to claim 7,
The method of detecting the position of the train vehicle, wherein the value of the differential correction data update time t is set to a very large value. In the method for detecting the position of a train vehicle according to claim 7,
The reception reliability coefficient is:
A method of detecting the position of a train vehicle, wherein the function is a function obtained by multiplying the sum of the first and second terms by the third term. In the method for detecting the position of a train vehicle according to claim 5,
When the information processing means specifies the current position of the train in the traveling section based on the DGPS position coordinates, the information processing means includes, among the DGPS coordinate information stored in the information storage means by the information measurement travel, the operation travel A line connecting the second position and the third position, which is a position of two pieces of coordinate information close to the first position which is a position obtained from the GPS information and the position correction information at the time, and connecting the second position and the third position A position at which a perpendicular line from the first position intersects with the line segment at a minute is defined as a current position of the train. In the method for detecting the position of a train vehicle according to claim 5,
The information processing means, when performing a comparison between the operational line curvature equivalent value and the known line curvature equivalent value, the known line curvature equivalent value data group and the operational line curvature equivalent value data group, Displaced by a certain distance, the deviation coefficient which is the sum of the squares of the differences between the operational line curvature equivalent value data and the known line curvature equivalent value data is minimized, or the operational line curvature equivalent value data and the A method for detecting a position of a train vehicle, wherein a distance corresponding to a case where the value of the cross-correlation coefficient of the known track curvature equivalent value data is maximum is specified as a current position of the train on the track. In the method for detecting the position of a train vehicle according to claim 5,
The information processing means, when it is determined that the reception reliability is high, according to a ratio of the travel distance calculated by the DGPS position coordinates to the travel distance calculated by the axle rotation speed, A method for detecting the position of a train vehicle, comprising correcting a value of a wheel diameter of the train when calculating a travel distance of the train from a number. A train-mounted device mounted on the train,
A system having a plurality of GPS satellites orbiting the earth, wherein the current position of the train on a track is detected by the train-mounted device,
The train mounted device,
GPS receiving means for receiving GPS information transmitted by radio waves from the GPS satellites and calculating GPS position coordinates based on the GPS information;
Azimuth angle detection means for detecting the azimuth angle of the vehicle body or bogie when the train is running,
Axle rotation speed detecting means for detecting the axle rotation speed of the train,
Information storage means for storing a line information database that associates the latitude and longitude, the known line curvature equivalent value that is a value corresponding to the curvature of the line, and the distance,
Equipped with information processing means,
The information processing means, when the train runs on the track, calculates a reception reliability coefficient representing a reception reliability which is a degree of reliability at the time of receiving the GPS information,
When the reception reliability is determined to be high, the information processing unit specifies a current position of the train in the traveling section based on the GPS position coordinates,
When the reception reliability is determined to be medium, the information processing means sets a distance value based on the GPS position coordinates as an initial value, and sets the azimuth angle and the axle rotation at each time during operation driving. By calculating the operating line curvature equivalent value that is a value corresponding to the line curvature during operation from the train traveling speed obtained from the number, and comparing it with the known line curvature equivalent value in the line information database, Identify the current position of the train in the travel section,
The train is characterized in that, when the reception reliability is determined to be low, the information processing means specifies a current position of the train in the traveling section based on a distance based on the axle rotation speed. Vehicle position detection system.

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