JP2003267220A - Moving object self-position detection method and moving object self-position detection system - Google Patents

Abstract

(57) [Problem] To provide a method and a system for detecting the position of a railway vehicle or the like based on GPS information or the like transmitted by radio waves from a plurality of GPS satellites orbiting the earth. SOLUTION: A DGPS is applied to a mobile traveling system, a first traveling of a railway vehicle 2 is performed, and after a ground marker 12 is detected, an information processing section 22 stores information at that time as known marker position coordinates. After the ground marker 12 is detected during the second and subsequent runs, the information processing unit 22 stores the known marker position coordinates closest to the current marker position coordinates at that time in the information storage unit 23. , And when the relative distance between the searched known marker position coordinate and the current marker position coordinate is equal to or smaller than the allowable value, the searched known marker position coordinate is output as the position coordinate of the ground marker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and system for detecting the position of a moving body based on GPS information or the like transmitted by radio waves from a plurality of GPS satellites orbiting the earth.

[0002]

2. Description of the Related Art Conventionally, as a method of detecting the traveling position of a railway vehicle in a railway, there is known a method of calculating a vehicle position based on a ground marker installed on the ground and an integrated distance from the ground marker. Has been. In this method, position coordinates and the like are measured in advance and a ground marker is set at a known position. As the ground marker, an ATS ground element or the like that transmits a radio wave to a railway vehicle is used.
In addition, the integrated distance from the ground marker is calculated by a speed generator or the like attached to the railway vehicle. The speed generator is a device that generates a pulse according to the number of rotations of an axle or an electric motor axle of a railway vehicle, and the rotation speed of the axle or the like is measured by this pulse. The position detection device mounted on the railway vehicle integrates the traveling distance of the railway vehicle from the rotation speeds of the axles obtained as described above, and identifies the current position of the railway vehicle from the position coordinates of the ground marker. To be done.

[0003]

However, in the above-mentioned conventional vehicle position detecting method, an error may be included in the accumulated distance due to wheel idling or sliding.
In addition, ground markers may be moved from their original position to other positions due to maintenance work or construction.In this case, the position coordinates after the relocation are measured and the data after the relocation is detected as the above-mentioned position detection. There was a problem that the obtained vehicle position would not be accurate unless it was reset in the system.

The present invention has been made to solve the above problems, and the problem to be solved by the present invention is based on GPS information or the like transmitted by radio waves from a plurality of GPS satellites orbiting the earth. It is to provide a method and system for detecting the position of a railway vehicle or the like.

[0005]

In order to solve the above-mentioned problems, a method for detecting a self-position of a moving body according to the present invention is directed to a plurality of ground markers installed in the vicinity of a traveling road and a moving body traveling on the traveling road. On-board mobile device, reference position station whose position is measured, and multiple GPs that orbit the earth
A method for detecting the position of the moving body by the moving body mounting apparatus using an S satellite, comprising:
Ground marker detecting means for detecting the ground marker, GPS information transmitted by radio waves from the GPS satellites,
GPS reception means for receiving position correction information transmitted by radio waves from the reference position station and calculating position coordinates based on the GPS information and the position correction information, an information storage means, and an information processing means are provided. When the first traveling of the mobile body is performed and the ground marker detecting means detects the ground marker, the information processing means stores the position coordinates at that time as known marker position coordinates in the information storage means. When the ground marker detection means detects the ground marker during the second and subsequent travels of the moving body, the information processing means stores the position coordinates at that time as the current marker position coordinates. The known marker position coordinate closest to the current marker position coordinate is searched from the information storage means, and the searched known marker position coordinate is the searched known marker position coordinate. When the relative distance between the position of the position coordinate and the position of the current marker position coordinate is less than or equal to the error allowable value, the search known marker position coordinate is set as the position coordinate of the ground marker detected by the ground marker detecting means. Is output.

In the above moving body self-position detecting method,
Preferably, the information processing means is based on the contents of the GPS information or the position correction information at the time of the first traveling of the moving body, at the time of reception of the ground marker detected by the ground marker detecting means. Of the GPS information and the position correction information, a reception reliability coefficient representing a reception reliability, which is a degree of reliability, is calculated, and the reception reliability is equal to or higher than a reliability reference value based on the value of the reception reliability coefficient. For the ground marker determined to be, the position coordinates relating to the ground marker are stored in the information storage means together with the reception reliability coefficient as the known marker position coordinates, and the reception reliability is based on the value of the reception reliability coefficient. For the ground marker that is determined to be lower than the reliability reference value, control is performed so that information is not stored in the information storage means.

Further, in the above-mentioned method for detecting the self-position of a mobile unit, preferably, the reception reliability coefficient is the GPS.
It is a function of the number n of the GPS satellites used for receiving information, and if n is a value of 4 or more, the larger the n is, the higher the reception reliability is. H, which is the rate of decrease in position accuracy in the horizontal direction at the observation point
It is a function of DOP, and is the time difference between the second term expressing that the smaller the HDOP is, the higher the reception reliability is, the latest time when the position correction information is received, and the calculation time of the reception reliability coefficient. It is a function of a certain differential correction data update time t, and is a function configured to have at least one of the third terms expressing that the reception reliability is higher as the t is smaller.

In the above moving body self-position detecting method, preferably, the reception reliability coefficient is a function obtained by multiplying the sum of the first term and the second term by the third term. Is.

Further, in the above moving body self-position detecting method, preferably, the information processing means is based on the contents of the GPS information or the position correction information when the moving body travels after the second time. Calculating the reception reliability coefficient for the ground marker detected by the ground marker detecting means, and the current marker reliability, which is the reception reliability at the position of the current marker position coordinate at the time of traveling this time, is the reliability reference value. When it is determined that it is the above, the search known marker reliability which is the reception reliability at the position of the search known marker position coordinates in which the relative distance between the position of the current marker position coordinates is equal to or less than the error tolerance value. And the current marker reliability are compared with each other, and when it is determined that the searched known marker reliability is equal to or higher than the current marker reliability, the ground detected by the ground marker detecting means is detected. Outputting the search known marker coordinates as the position coordinates of the over mosquitoes.

Further, in the above moving body self-position detecting method, preferably, the information processing means is a result of comparison between the retrieved known marker reliability and the current marker reliability,
When it is determined that the current marker reliability is higher than the searched known marker reliability, the current marker position coordinates are output as the position coordinates of the ground marker detected by the ground marker detecting means, and the current marker is also output. The position coordinates are stored as new known marker position coordinates in the information storage means together with the reception reliability coefficient thereof.

In the mobile body self-position detecting method, preferably, the information processing means is based on the contents of the GPS information or the position correction information when the mobile body travels after the second time. Calculating the reception reliability coefficient for the ground marker detected by the ground marker detecting means, and the current marker reliability, which is the reception reliability at the position of the current marker position coordinate at the time of traveling this time, is the reliability reference value. If it is determined that the above is the above, the known marker position coordinate closest to the position of the current marker position coordinate is searched from the information storage means, and the searched known marker position which is the searched known marker position coordinate. When the relative distance between the coordinate position and the current marker position coordinate position is larger than the error tolerance, the position of the ground marker detected by the ground marker detecting means is detected. Outputs the current marker position coordinates as coordinates, the current marker position coordinates as a new known marker coordinates, is stored together with the received reliability index in the information storage means.

Further, in the above-mentioned mobile body self-position detecting method, preferably, the information processing means is based on the contents of the GPS information or the position correction information when the mobile body travels after the second time. Calculating the reception reliability coefficient for the ground marker detected by the ground marker detecting means, and the current marker reliability, which is the reception reliability at the position of the current marker position coordinate at the time of traveling this time, is the reliability reference value. When it is determined that it is less than the above, the control is performed so that the position coordinates of the ground marker detected by the ground marker detecting means are not output.

Further, the moving body self-position detecting system according to the present invention is installed in the vicinity of a traveling road, and a plurality of ground markers whose positions are previously measured and known,
A mobile body mounting device mounted on a mobile body traveling on the traveling path, a reference position station whose position is measured, and a plurality of GPS satellites orbiting the earth, and the position of the mobile body A system detected by an on-board device, wherein the mobile device-on-board device detects ground markers, ground marker detection means, GPS information transmitted by radio waves from the GPS satellites, and radio waves transmitted from the reference position station. GPS receiving means for receiving the position correction information, and calculating position coordinates based on the GPS information and the position correction information, information storing means for storing the position coordinates of the ground marker as known marker position coordinates, When the ground marker detecting means detects the ground marker, the position coordinates at that time are set as the current marker position coordinates, and the current marker position coordinates are most The known marker position coordinates are searched from the information storage means, and the relative distance between the position of the searched known marker position coordinates which is the searched known marker position coordinates and the position of the current marker position coordinates is an allowable error value. In the case of the following, it is characterized by comprising information processing means for outputting the search known marker position coordinates as the position coordinates of the ground marker detected by the ground marker detecting means.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a train vehicle position detection system which is an embodiment of the present invention.

As shown in FIG. 1, this train vehicle position detection system 100 includes a ground marker 12 and a vehicle-mounted device 2.
0, reference position station 3, GPS satellites G1, G2, G3
, Gn.

The ground marker 12 is installed near the railroad track 11. Further, the ground markers 12 are arranged at a plurality of positions in the longitudinal direction of the railroad track, respectively. As the ground marker 12, a ground child of an ATS (Automatic Train Stop) that transmits radio waves to a railway vehicle or an ATC (Automatic Train Stop).
An ic train control (automatic train control device) ground element or the like is used. Railroad track 11
Corresponds to the traveling path in the claims.

Further, the vehicle-mounted device 20 includes the railroad track 12
It is mounted on a railway vehicle 2 that travels. Here, the railway vehicle 2 corresponds to a moving body mounting device in the claims, and the vehicle mounting device 20 corresponds to a moving body mounting device in the claims.

The position of the reference position station 3 is measured in advance and known. The reference position station 3 has a transmission antenna 31, and transmits position correction information regarding the position, time, etc. of the reference position station 3 by radio waves.

The plurality of GPS satellites G1 to Gn are artificial satellites that orbit the earth, and their positioning codes, orbit information of the sender GPS satellite (three-dimensional position coordinates and time of the sender GPS satellite, etc.). GPS (including information about
Information is transmitted by radio waves.

Therefore, the ground marker 12, the vehicle-mounted device 20, the plurality of GPS satellites G1 to Gn, and the reference base station 3
Enables DGPS (Differential Glo
bal Positioning System).

The above-described vehicle-mounted device 20 includes a ground marker detection unit 21, an information processing unit 22, an information storage unit 23,
It has a first antenna 24, a second antenna 25, a GPS processing unit 26, and a differential receiving unit 27. Here, the ground marker detecting unit 21 corresponds to the ground marker detecting means in the claims, and the information processing unit 22.
Corresponds to the information processing means in the claims, and the information storage means 23 corresponds to the information storage means in the claims. The first antenna 24, the GPS processing unit 26, the second antenna 25, and the differential receiving unit 27 correspond to GPS receiving means in the claims.

The ground marker detecting section 21 is a section for detecting a pulse signal or the like transmitted from the ground marker 12 and outputting it to the information processing section 22. In addition, the first antenna 24
Detects radio waves transmitted from GPS satellites G1 etc.
It is output to the PS processing unit 26. In addition, the second antenna 25
Detects the radio wave transmitted from the reference position station 3 and outputs it to the differential receiving unit 27. The differential receiving unit 27 transmits the radio wave detected by the second antenna 25 to G
It is output to the PS processing unit 26. The GPS processing unit 26 extracts GPS information and position correction information from these inputs and outputs them to the information processing unit 22.

The information processing section 22 is a section for processing and analyzing the GPS information and the position correction information sent from the GPS processing section 26. Although not shown, the information processing unit 22 has a CPU (Central Processing).
Unit: central processing unit), RAM, interface, data / command input unit, image display unit, etc.

Although not shown, the CPU has an internal bus which is a signal line for exchanging currents (signals) inside the CPU. The internal bus has an arithmetic unit and a register. , A clock generation unit, an instruction processing unit, and the like. The arithmetic unit in the CPU generally performs four arithmetic operations (addition, subtraction, multiplication, and division) on various data stored in registers, or logical operations (logical product, logical sum, negation, exclusive). Is a part for performing processing such as data OR, data comparison, or data shift. The processing result is generally stored in a register.

The register is a part that generally stores one word of data. Usually, a plurality of registers are provided in the CPU. The clock generation unit is a unit that generates a clock signal (clock signal) for synchronizing the time of each unit of the CPU. The CPU operates based on this clock signal. The instruction processing unit is a unit that controls and processes fetching, decoding, and execution of an instruction to be executed by the arithmetic unit and the like.

The information storage unit 23 is not shown in the figure,
Hard disk drive (HDD), ROM (Read O
nly Memory: a read-only memory) and the like, and a control program for controlling the CPU and a CP
This is a part that stores various data used by U. Although not shown, the hard disk device has a disk-shaped magnetic disk inside, and this magnetic disk is rotationally driven by a disk drive mechanism, and a magnetic head is driven by a head drive mechanism at an arbitrary position of the magnetic disk. To record data by magnetizing the magnetic film on the surface of the magnetic disk with a write current from the magnetic head,
This is a device for reading recorded data by detecting a current flowing through a coil of the magnetic head when the magnetic head moves on the magnetized magnetic film. The ROM is generally composed of a semiconductor chip or the like.

The control program described above is an OS (Ope)
In addition to basic CPU software such as a rating system), a processing procedure such as an instruction for causing the CPU to execute image processing and analytical calculation is a set of characters and symbols described in a predetermined programming language.

Although not shown, the information processing unit 22 is a RAM (Random Access Memory).
ry: write / read memory as needed) and the like. RA
M is a portion for temporarily storing data and the like in the process of being calculated by the CPU. The RAM is generally composed of a semiconductor chip or the like.

Although not shown, the information processing section 22 has an interface (I / O). The interface has a signal line or a bus, which is a set of the lines, various connectors, various ports, a read / write control mechanism for the hard disk device, etc., and is a part for exchanging signals from the CPU and signals from each device. Is.

Although not shown, the information processing section 22 has a data / input section. The data / command input unit has a keyboard, a trackball, a pointing device including a touch pad, a stick pointer, or the like, a touch panel device, etc., and inputs a command signal to the CPU, data processed by the CPU, or the like from the outside. It is a part for.

The information processing unit 22 has an image display unit (not shown). The image display is a CRT
(Cathode Ray Tube: Cathode Ray Tube Display Device) It has a monitor, a liquid crystal display panel, a plasma display device, and the like, and is a part for displaying the calculation result of the CPU and the processed data on the screen as images and characters.

The information processing unit 22 has an output unit (not shown). The output unit includes a printer, an external output terminal, a communication device such as a modem, and a LAN (Local).
Area Network) port, etc.
It is a part that prints the calculation result of the CPU or the processed data on paper or the like, or outputs or transmits it as an electric signal to the outside. If an external recording device such as a flexible disk (FD) device, a magneto-optical disk device, or a PC card device is connected to the external output terminal, the recorded impact sound data, the result data processed by the CPU, and the like are recorded on the disk or the like. It can be recorded on the recording medium of and taken out.

Although not shown, the GPS processing unit 26 in the train own vehicle position detection system 100 of the present embodiment also has a configuration and operation similar to those described above.
It has a PU, a RAM, a ROM, an interface, a data / command input unit, and the like.

Next, the operation performed by the train vehicle position detection system 100 described above will be described in more detail with reference to FIGS. 2 to 4.

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.

The GPS satellites G1 and the like are about 200 above the earth.
It is an artificial satellite that orbits the earth at 00 km. The orbit has six different orbits, and the orbits of the orbits are shifted by 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, four or more GPS satellites can be seen at any point on the earth.

Radio signals for positioning are transmitted from the respective GPS satellites G1 and the like. This radio wave signal is a digital signal, and the digital signal includes a positioning code repeated every predetermined period (for example, 1 millisecond), orbit information of the transmitted GPS satellite, and the like. This positioning code is also generated inside the GPS processing unit 26. Therefore, if the time of the clock mounted on the GPS satellite G1 or the like and the time of the clock of the receiving side (for example, the GPS processing unit 26) match without error, the time difference of the positioning code (hereinafter, By detecting the “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.

That is, the pseudo distance from the radio wave reception position from the GPS satellite to a certain GPS satellite can be obtained by multiplying the time difference by the radio wave velocity (light velocity). The three-dimensional position coordinates of the GPS satellite at each time can be calculated from the above orbit information in the digital signal. If the three-dimensional position coordinate of a GPS satellite at a certain time is (α, β, γ), the three-dimensional position coordinate of the GPS radio wave reception position is (x, y, z), and the pseudo distance at that time is R. , The following equation (1) is established. (X-α) ² + (y-β) ² + (z-γ) ² = R ² ......... (1)

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 to calculate the pseudo distance, By obtaining three relational expressions similar to the above equation (1) and solving them, the values of x, y, z can be obtained. However, since there is a time error between the GPS satellite clock and the receiving device clock, the calculated pseudorange R includes an error ΔR. Therefore, the above method cannot uniquely determine the values of x, y, and z.

In order to solve this, radio waves from at least four different GPS satellites are simultaneously received to calculate a pseudorange, and at least four relational expressions similar to the above equation (1) are calculated.
If the number is obtained, the values of x, y, and z can be uniquely determined while considering ΔR. The GPS processing unit 26 in the train own vehicle position detection system 100 of the present embodiment is configured to output the number n of the received GPS satellites to the information processing unit 22.

Even if four or more GPS satellites are captured and their radio signals are obtained, the positioning accuracy is rather lowered depending on the relative arrangement of the GPS satellites. This is due to its geometrical nature. For this reason, the accuracy in such a case is determined by the geometric accuracy reduction rate (Geometry).
c Direction of Precision: Hereinafter referred to as "GDOP". ).

The smaller the value of GDOP, the higher the accuracy. For example, the greater the relative angle between the GPS radio signal reception position and the lines connecting the GPS satellites, the greater the GDO.
The value of P becomes smaller. Therefore, the larger the volume of the tetrahedron created by connecting the four GPS satellites, the smaller the GDOP value. Therefore, in the GPS processing unit 26, when five or more GPS satellites are captured, the GDO
A combination of four GPS satellites that minimizes the P value is selected, and this is adopted for positioning calculation.

The above GDOP is expressed by the following equation (2). GDOP ² = PDOP ² + TDOP ² ………… (2)

In the above equation (2), PDOP is the deterioration rate (Position) of the position accuracy at the observation point on the earth.
Dilution of Precision: Hereinafter referred to as "position accuracy reduction rate". ) Is shown, and TD
OP is the time accuracy reduction rate (Time Dilutio).
no of Precision: Hereinafter referred to as "time accuracy deterioration rate". ) Is shown.

PDOP is represented by the following equation (3). PDOP ² = HDOP ² + VDOP ² ……… (3)

In the above equation (3), HDOP is the rate of decrease in the position accuracy in the horizontal direction at the observation points on the earth (Ho.
rizontal dilution of prec
Ision: Hereinafter referred to as "horizontal position accuracy reduction rate". ), VDOP is the rate of decrease in vertical position accuracy (Vertical) at an observation point on the earth.
Dilution of Precision: Below,
This is called the "vertical position accuracy reduction rate." ) Is shown.

Train Vehicle Position Detection System 1 of this Embodiment
The GPS processing unit 26 in 00 is configured to output the HDOP value calculated using a predetermined proportional constant to the information processing unit 22.

The above explanation is based on the GPS (Global P
(positioning System: Global Positioning System). A radio signal from a normal GPS satellite includes a delay of a radio wave due to the influence of an ionosphere and a convection layer, an error of a clock on the GPS receiving device side, and an error of a clock on the GPS satellite. For this reason,
Due to these influences, the positioning result also includes an error. The purpose of DGPS is to reduce such errors and increase the accuracy of positioning results.

In the DGPS, in addition to the GPS satellite and the receiver, at the reference position where accurate position data (latitude, longitude, height on the earth ellipsoid) is measured by surveying or the like, positioning by the above GPS (single Positioning). As a result, both known position data of the reference position (reference position data) and position data by the GPS at that time (GPS position data) are obtained. Reference position data and GPS
The difference in position data can be used as a correction amount at another position.

Therefore, if the data of the difference between the reference position data and the GPS position data is calculated in real time and transmitted as radio wave as the position correction information, the GPS of the position correction information is received at other locations. By performing correction by subtracting the correction amount indicated in the position correction information from the position coordinates calculated by the independent positioning, a more highly accurate value can be obtained. Such a system is DGP
It is S. Train own vehicle position detection system 10 of the present embodiment
In 0, the position of the reference position station 3 is known, and the reference position station 3 transmits the position correction information in real time.

In the DGPS, it is ideal to use the position correction information from the reference position station to correct the GPS positioning position at the same time, but in reality, the position correction information from the reference position station is used. , GPS at a certain time
It will be used to correct the positioning position. However, since the GPS satellites are moving every moment, an error will appear in the position correction information as time passes. The time at which other locations are corrected when the transmission time of the position correction information from the reference position station is used as the reference is the "delay time", and τ
It is known that the error of the position correction information is proportional to τ ² when expressed by. The GPS processing unit 26 in the train vehicle position detection system 100 according to the present embodiment determines the time difference between the latest time when the position correction information is received and the time of the data to be corrected as the differential correction data update time t.
Is configured to be output to the information processing unit 22.

Next, the operation of the train vehicle position detection system 100 of the present embodiment equipped with the DGPS as described above will be described in more detail.

First, as shown in FIG. 2 (A), the railway vehicle 2 travels the railroad track 11 for the first time. In FIG. 2, the railroad track 11 is installed in the left-right direction of the drawing, and the railcar 2 is illustrated as traveling from the left to the right of the drawing. In this first run, the ground marker detector 21 (see FIG. 1) causes the ground marker m1 (see FIG. 2).
(B)), the pulse signal transmitted from the ground marker m1 is detected by the ground marker detector 21 (see FIG. 2C).

Upon receiving the pulse signal detection from the ground marker, the CPU (not shown) in the information processing unit 22 receives from the GPS information and the position correction information input from the GPS processing unit 26 at that time. Calculate the reliability coefficient. 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.

When the reception reliability coefficient is represented by c, the reception reliability coefficient c is expressed by the following equation (4). c = {f (n) + g (HDOP)} × h (t) ... (4) In this case, the larger the value of c, the higher the reliability of reception.

In the above equation (4), the first term f
(N) shows 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 from 0 to 3. 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.
When the value of n is 5, the value of f (n) is 5. The following is the same.

As described above, in order to obtain the position coordinates at the receiving position in DGPS, the number n of GPS satellites must be at least 4 as in the case of general GPS single positioning. Therefore, when n is 3 or less, the degree of positioning reliability is the lowest, and thus it is set to zero. Also, if n is 4 or more, GDOP (or HDO
The combination of GPS satellites (4) is the best (4)
Can be selected, and the larger the value of n,
Since it is possible to select an accurate combination,
The degree of reliability of positioning increases. To express this property,
When n is 4 or more, f (n) = n.

The function of f (n) may be other than the above. For example, when n is 3 or less, a constant value k other than zero may be set. Further, in this case, when n is 4 or more, f (n) = n ² + k may be set. Alternatively, when n is 3 or less, and a constant value k other than zero, when n of 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 constant value k other than zero is set, and when n is 4 or more, f (n) = f1 (n)
It may be + 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 may be any function that increases from k when n is 4 or more.

In the above equation (4), the second term g (HDOP) represents a function of the horizontal position accuracy reduction rate HDOP. When HDOP is represented by p for simplification, g (p) is a function whose value increases as p decreases. For example, g (p) is p
The function may be inversely proportional to, g (p) = 1 / p. Alternatively, g (p) is a function inversely proportional to p ² , g (p)
= 1 / p ² may be used. In general, g (p) may be a function inversely proportional to p ^b , g (p) = 1 / p ^b . In this case, b is an integer of 1 or more.

As described above, in the DGPS, in order to increase the horizontal position accuracy at the reception position, the smaller the horizontal position accuracy reduction rate HDOP is, the more advantageous it is. Therefore, g (p) is set to be a function that takes a larger value as HDOP becomes smaller.

The function of g (p) may be other than the above. For example, in general, g (p) is a function that is inversely proportional to p ^b and that has an intercept when b is zero,
It may be g (p) = 1 / (p + e) ^b . 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 it has a larger value as HDOP becomes smaller.

In the above equation (4), the third term h (t) is the differential correction data update time t.
Shows the function of. The value of h (t) decreases as t ² increases, and becomes a function having an intercept when t is zero. For example, h (t) is h (t) =
It may be 1 / (t ² + q) ^r . In this case, q is a positive real number and r is an integer of 1 or more.

As described above, in DGPS, the smaller the value of the differential correction data update time t, the more advantageous it is to increase the position accuracy at the reception position. Also, the error increases in proportion to the value of t ² . Therefore, h (t) is set to be a function that takes a larger value as t ² is smaller.

The function of h (t) may be other than the above. In short, the function h (t) may be any function as long as t ² has a smaller value.

The reception reliability coefficient c is not limited to the function of the above equation (4). Generally, if the function is configured to have at least one of the first term f (n), the second term g (HDOP), and the third term h (t) of the above equation (4),
It can be any function. For example, the first term f
It may be the sum of (n), the second term g (HDOP), and the third term h (t). Alternatively, the first term f (n) and the second term g
It may be a product of (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, the second term g (HDO
It may be a function obtained by multiplying the sum of P) 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.

CPU in information processing unit 22 (not shown)
2D, after calculating the reception reliability coefficient c11 at the time of the ground marker m1 in which the pulse signal is detected, the reliability reference value stored in the information storage unit 23 and The calculated reception reliability coefficient c11 is compared. As a result, if the calculated reception reliability coefficient c11 is greater than or equal to the reliability reference value, the CPU (not shown) in the information processing unit 22 is the original data from which the reception reliability coefficient c11 is calculated. It is determined that the GPS information and the position correction information have high reliability, and from the GPS information and the position correction information in this case, the latitude value a11, the longitude value b11, and the reception reliability coefficient c11 of the ground marker m1 at the time of reception. Information storage unit 2
3 is stored in the reference data table.

FIG. 3 shows the structure of the reference data table of the information storage unit 23. As shown in FIG. 3, the marker having the latitude a11, the longitude b11, and the reception reliability coefficient c11 is stored in the reference data table of the information storage unit 23 as the known marker M1 (see FIG. 2E). In this case, the latitude a11 and the longitude b11 are the known marker position coordinates of the known marker M1. The reception reliability coefficient c11 in this case is the known marker reliability.

Next, the railway vehicle 2 moves to the right in FIG. 1, and the ground marker detecting section 21 (see FIG. 1) reaches a position near the ground marker m2 (see FIG. 2B). In this case, the pulse signal transmitted from the ground marker m2 is detected by the ground marker detection unit 21 (see FIG. 2 (C)).
Then, the CPU (not shown) in the information processing unit 22 calculates the reception reliability coefficient c12 from the GPS information and the position correction information input from the GPS processing unit 26 at that time.

CPU in information processing unit 22 (not shown)
2D, as shown in FIG. 2D, after calculating the reception reliability coefficient c12 at the time of the ground marker m2 where the pulse signal is detected, the reliability reference value stored in the information storage unit 23, The calculated reception reliability coefficient c12 is compared. As a result, when the calculated reception reliability coefficient c12 is less than the reliability reference value, the CPU (not shown) in the information processing unit 22 uses the original data obtained by calculating the reception reliability coefficient c12. It is determined that the reliability of certain GPS information and position correction information is low, and the data of this ground marker m2 is not stored in the reference data table of the information storage unit 23.

Next, the railway vehicle 2 moves further to the right in FIG. 2 (A), and the ground marker detecting unit 21 (see FIG. 1) is located near the ground marker m3 (see FIG. 2B). Reach In this case, the pulse signal transmitted from the ground marker m3 is detected by the ground marker detector 21 (FIG. 2).
(See (C)) and the CPU (not shown) in the information processing unit 22 uses the reception reliability coefficient c1 from the GPS information and the position correction information input from the GPS processing unit 26 at that time.
Calculate 3.

CPU in information processing unit 22 (not shown)
2D, after calculating the reception reliability coefficient c13 at the time of the ground marker m3 where the pulse signal is detected, the reliability reference value stored in the information storage unit 23, The calculated reception reliability coefficient c13 is compared. As a result, if the calculated reception reliability coefficient c13 is greater than or equal to the reliability reference value, the CPU (not shown) in the information processing unit 22 is the original data from which the reception reliability coefficient c13 is calculated. It is determined that the reliability of the GPS information and the position correction information is high, and from the GPS information and the position correction information in this case, the latitude value a13, the longitude value b13, and the reception reliability coefficient c13 of the ground marker m3 at the time of reception. Information storage unit 2
3 is stored in the reference data table.

Therefore, as shown in the reference data table of FIG. 3, the marker having the latitude a13, the longitude b13, and the reception reliability coefficient c13 is a known marker M2 (see FIG. 2E) in the information storage unit 23. It is stored in the reference data table. In this case, the latitude a13 and the longitude b13 correspond to the known marker position coordinates of the known marker M2 in the claims.

By performing the first run of the railway vehicle 2 as described above, the value of the reception reliability coefficient c becomes equal to or higher than the predetermined reliability reference value as shown in the reference data table of FIG. The ground marker is stored as the known marker M, and the known marker position coordinates (latitude a, longitude b) that is the position data thereof and the value of the reception reliability coefficient c are stored in the reference data table. This first run is a preparatory work for detecting the own vehicle position of the train by the train own vehicle position detection system 100 of the present embodiment. By this first run,
After the reference data table is created and stored in the information storage unit 23, the vehicle position can be detected by this system.

FIG. 4 is a diagram for explaining the operation of the train vehicle position detection system 100 of this embodiment in the case where the railway vehicle 2 is traveling for the second time and thereafter. As shown in FIG. 4 (A), during the second and subsequent runnings of the railway vehicle 2, the railway vehicle 2 moves to the right in FIG. 4 (A), and the ground marker detection unit 21 (see FIG. 1). Known ground marker, eg M1
(See FIG. 4B) near position P1 (see FIG. 4C)
Reach In this case, the pulse signal is the ground marker detection unit 2
1 (see FIG. 4C), the CPU (not shown) in the information processing unit 22 receives from the GPS information and the position correction information input from the GPS processing unit 26 at that time. The reliability coefficient c21 is calculated.

CPU in information processing unit 22 (not shown)
4D, the reception reliability coefficient c21 at the time of the position P1 (see FIG. 4C) where the pulse signal is detected is calculated and then stored in the information storage unit 23. The reliability reference value that is present is compared with the calculated reception reliability coefficient c21. As a result, the calculated reception reliability coefficient c21
Is greater than or equal to the reliability reference value, C in the information processing unit 22
The PU (not shown) determines that the reliability of the GPS information and the position correction information at the time of reception of the current travel, which is the original data obtained by calculating the reception reliability coefficient c21, is high, and the GP in this case
Based on the S information and the position correction information, the latitude value a2 of the pulse signal detection position P1 (see FIG. 4C) at the time of the current reception
1 and the value of the longitude value b21 are calculated. In this case, the latitude a21 and the longitude b21 correspond to the current marker position coordinates in the claims.

Next, the CPU (not shown) in the information processing unit 22 selects from the reference data table of the information storage unit 23,
This time's current marker position coordinates (latitude a21, longitude b21)
The known marker position coordinate closest to is searched. Examples of the search method include a method of calculating the distance between the point represented by the current marker position coordinates and the point represented by the known marker position coordinates, and searching for the known marker position coordinates that minimizes the value. For example, the current marker position coordinate of this time is (latitude a2
1, longitude b21) and the known marker position coordinates are (latitude a1
1, the longitude b11), the distance L between these two points (hereinafter, referred to as "relative distance") is represented by the following equation (5). L = {(a21-a11) 2 + (b21-b11) 2} 1/2 ......... (5)

Alternatively, the current marker position coordinates (latitude a21, longitude b21) of this time are set as xy with respect to a certain position.
The coordinate system is converted to calculate (x21, y21), and the known marker position coordinates (latitude a11, longitude b11) are converted to the above xy coordinate system to calculate (x11, y11), and 2
The relative distance L between the points may be calculated by the following equation (6). L = {(x21-x11) 2 + (y21-y11) 2} 1/2 ......... (6)

Next, the CPU (not shown) in the information processing section 22 obtains the minimum value L1 of the relative distance calculated as described above (see FIG. 4E), and the known marker at that time is obtained. Is identified as M1 and its position coordinates are identified. Next, the CPU (not shown) in the information processing unit 22 compares the minimum value L1 of the relative distance described above with the allowable error value stored in the information storage unit 23. The allowable error value is, for example, 5 to 10
It is about meters. This is because, when the ground marker is not relocated, it is known from the positioning accuracy by GPS that the positioning result at the same point falls within the range of about 5 to 10 meters.

As a result of the above comparison, the minimum value L1 of the relative distance
Is less than or equal to the error tolerance, the CPU (not shown) in the information processing unit 22 determines that the point P1 (see FIG. 4A) where the pulse signal is detected during the current traveling is the known marker M.
It is determined to be 1.

Next, the CPU (not shown) in the information processing unit 22 operates at the point P1 where the pulse signal is detected during the current traveling.
The current reference data table as the position of (see Figure 3)
The known marker position coordinates (latitude a11, longitude b11) of the known marker M1 stored in
It is determined whether to adopt the current marker position coordinates (latitude a21, longitude b21) of the point P1 where the pulse signal is detected during traveling this time.

This determination is performed by using the reception reliability coefficient c11 (known marker reliability) of the known marker M1 stored in the current reference data table (see FIG. 3) and the point P1 at which the pulse signal is detected during the current traveling. The value of the reception reliability coefficient c21 (current marker reliability) at the time of is compared.

As a result of the above comparison, the known marker reliability c11, which is the reception reliability coefficient of the known marker M1, is the reception reliability coefficient at the time when the vehicle was traveling at the point P1 where the pulse signal was detected during traveling this time. Current marker reliability c2
When the value is 1 or more, that is, when c11 ≧ c21, the CPU (not shown) in the information processing unit 22 determines that the data stored in the current reference data table (see FIG. 3) is better. Determined to be highly reliable.

As a result, the CPU (not shown) in the information processing unit 22 finds the position coordinates of the ground marker at the point P1 at which the pulse signal is detected during the current traveling, in the current reference data table (see FIG. 3). ) Is stored in the position coordinates (latitude a11, longitude b11). As a result, the CPU (not shown) in the information processing unit 22
The position coordinates of the railway vehicle 2 at the time of traveling at the point P1 where the pulse signal is detected during traveling this time are (latitude a
11, the longitude b11) is output. These times and the position coordinates at that time are also stored in a predetermined storage area in the information storage unit 23. In this case, the data of the known marker M1, the latitude a11, the longitude b11, and the reception reliability coefficient c11 stored in the current reference data table (see FIG. 3) are stored as they are without being changed. (See FIG. 4 (F)).

If the magnitude relationship between the relative distance and the error tolerance or the magnitude relationship between the known marker reliability and the current marker reliability is different, the CPU (not shown) in the information processing unit 22 is different from the above. Do different processing.

When the railroad vehicle 2 moves to the right in FIG. 4A, the ground marker detecting section 21 (see FIG. 1) causes a position P2 near a known ground marker, for example, M2 (see FIG. 4B). (See FIG. 4C). In this case, the pulse signal is detected by the ground marker detector 21 (FIG. 4).
(See (C)) and the CPU (not shown) in the information processing unit 22 receives the reception reliability coefficient c2 from the GPS information and the position correction information input from the GPS processing unit 26 at that time.
Calculate 2.

CPU in information processing unit 22 (not shown)
4D, the reception reliability coefficient c22 at the time of the position P2 (see FIG. 4C) where the pulse signal is detected is calculated and then stored in the information storage unit 23. The calculated reliability standard value is compared with the calculated reliability standard value. As a result, the calculated reception reliability coefficient c22
Is greater than or equal to the reliability reference value, C in the information processing unit 22
The PU (not shown) determines that the reliability of the GPS information and the position correction information at the time of reception of the current travel, which is the original data obtained by calculating the reception reliability coefficient c22, is high, and the GP in this case
From the S information and the position correction information, the value of the current marker position coordinates (latitude a22, longitude b22) of the pulse signal detection position P2 (see FIG. 4C) at the time of this reception is calculated.

Next, the CPU (not shown) in the information processing unit 22 selects from the reference data table of the information storage unit 23,
This time's current marker position coordinates (latitude a22, longitude b22)
The known marker position coordinate closest to is searched for by the same method as above.

In this case, the CPU (not shown) in the information processing unit 22 performs the minimum value L2 of the relative distance between the current marker position and the known marker position in the same manner as described above (FIG. 4 (E)).
Reference), and the known marker at that time is specified as M2,
The position coordinates are specified. Next, C in the information processing unit 22
PU (not shown) is the minimum value L2 of the above relative distance,
The allowable error values stored in the information storage unit 23 are compared.

As a result of the above comparison, the minimum relative distance L2
Is less than or equal to the error allowable value, the CPU (not shown) in the information processing unit 22 determines that the point P2 (see FIG. 4A) where the pulse signal is detected during the current traveling is the known marker M.
It is determined to be 2.

Next, the CPU (not shown) in the information processing unit 22 operates at the point P2 where the pulse signal is detected during traveling this time.
The current reference data table as the position of (see Figure 3)
The known marker position coordinates (latitude a13, longitude b13) of the known marker M2 stored in
Whether to adopt the current marker position coordinates (latitude a22, longitude b22) of the point P2 where the pulse signal is detected during traveling this time is determined by the same method as described above.

As a result of this comparison, the known marker reliability c13 which is the reception reliability coefficient of the known marker M2 (see FIG. 3).
Is less than the value of the current marker reliability c22 which is the reception reliability coefficient at the time of traveling at the point P2 where the pulse signal was detected during traveling this time, that is, c13 <c
In the case of No. 22, the CPU (not shown) in the information processing unit 22 is more reliable than the data currently stored in the reference data table (see FIG. 3) at the time of traveling this time. To determine.

As a result, the CPU (not shown) in the information processing unit 22 determines that the position coordinates of the ground marker at the point P2 where the pulse signal is detected during the current traveling are the positions received and calculated during the current traveling. Coordinates (latitude a22, longitude b2
2) is determined. As a result, the information processing unit 22
A CPU (not shown) therein outputs that the position coordinates of the railway vehicle 2 at the time of traveling at the point P2 where the pulse signal is detected during traveling this time are (latitude a22, longitude b22). These times and the position coordinates at that time are also stored in a predetermined storage area in the information storage unit 23. Further, in this case, the data of the known marker M2 stored in the current reference data table (see FIG. 3) includes the known marker M2 ′ and the latitude a2 as shown in FIG.
2, longitude b22, and reception reliability coefficient c22 are changed and stored (see FIG. 4 (F)).

In some cases, it may be different from the above.
In that case, a CPU (not shown) in the information processing unit 22
Performs processing different from the above.

For example, when the pulse signal is detected by the ground marker detecting section 21 at the above-mentioned point P2 (see FIG. 4).
(See (C)), a CPU (not shown) in the information processing unit 22 receives a reception reliability coefficient c2 from the GPS information and the position correction information input from the GPS processing unit 26 at that time.
When 2 is calculated, the calculated reception reliability coefficient c22
Is less than the reliability reference value, the information processing unit 2
The CPU (not shown) in 2 judges that the reliability of the GPS information and the position correction information at the time of the reception of the current traveling, which is the original data for calculating the reception reliability coefficient, is low, and the subsequent processing is performed. Absent. Therefore, the own vehicle position of the train at this time is not detected and is not output. The stored data in the reference data table is not changed either.

Alternatively, as shown in FIG. 6, a certain point P
In *, the pulse signal is detected by the ground marker detector 21 (see FIG. 6C), and the reception reliability coefficient c32 (see FIG. 6).
(See (D)) is greater than or equal to the reliability reference value, the minimum value of the relative distance between the current marker position and the known marker position may exceed the allowable error value. In such a case, "the existing ground marker was relocated for some reason" or "it was not stored in the reference data table because the reception reliability coefficient was less than the reliability reference value in the previous run. The situation such as "is possible. In this case, as shown in FIG. 7, the CPU (not shown) in the information processing unit 22 uses the position coordinates (latitude a32, longitude b32) and the reception reliability coefficient as another new marker M *. c32 is stored in the reference data table in the information storage unit 23. As a result, the CP in the information processing unit 22
U (not shown) outputs that the position coordinates of the railway vehicle 2 at the time of traveling at the point P * where the pulse signal was detected during traveling this time are (latitude a32, longitude b32). These times and the position coordinates at that time are also stored in a predetermined storage area in the information storage unit 23.

Train own vehicle position detection system 1 of this embodiment
According to 00, every time the ground marker is reached, DGPS
It has an advantage that the position coordinates can be detected by the positioning using, and the position can be accurately detected even when the ground marker is relocated.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and has a configuration substantially the same as the technical idea described in the scope of claims of the present invention, and those having the same operational effect,
Anything is included in the technical scope of the present invention.

For example, in the above-mentioned embodiment, the ATS ground element and the ATC ground element are described as examples of ground markers, but the present invention is not limited to this, and ground markers of other configurations, for example, It may be a ground marker newly installed exclusively for this system. The ground marker may have any configuration as long as it has a function of transmitting a radio wave such as a pulse signal to the railway vehicle.

Further, in the above embodiment, the CPU (not shown) of the information processing unit 22 which is the information processing means calculates the reception reliability coefficient after the pulse signal from the ground marker is detected and calculates the reliability. Although the processing procedure for executing the comparison process of comparing with the degree reference value has been described as an example, the present invention is not limited to this, and the information processing means may perform the processing procedure of other contents. . For example, the processing procedure may be such that the calculation of the reception reliability coefficient and the comparison with the reliability reference value are not performed. In this case, during the first travel, after the pulse signal from the ground marker is detected, the position coordinate at that time is stored in the information storage means as the known marker position coordinate. Further, in the second and subsequent runs, after the pulse signal from the ground marker is detected, the position coordinate at that time is set as the current marker position coordinate, and the known marker position coordinate closest to the current marker position coordinate is stored in the information. If the relative distance between the position of the search known marker position coordinate which is the known marker position coordinate searched and the position of the current marker position coordinate is less than the error tolerance, the ground marker detection is performed. The search known marker position coordinates are output as the position coordinates of the ground marker detected by the means.

Further, in the above-mentioned embodiment, the railcar is taken as an example of the moving body, but the present invention is not limited to this, and a moving body having another structure, for example, a new transportation system or a monorail. Etc. may be applied.

[0102]

As described above, according to the present invention,
When the DGPS is applied to the moving body traveling system, the information processing means and the information storing means are provided, the first traveling of the moving body is performed, and the ground marker detecting means detects the ground marker, the information processing means: The position coordinates at that time are stored in the information storage unit as known marker position coordinates, and when the ground marker detection unit detects the ground marker during the second and subsequent traveling of the moving body, the information processing unit, The position coordinate at that time is set as the current marker position coordinate, the known marker position coordinate closest to the current marker position coordinate is searched from the information storage means, and the position of the searched search known marker position coordinate and the current marker position coordinate are calculated. If the relative distance of is less than or equal to the error tolerance, the search known marker position coordinates are output as the position coordinates of the ground marker, so the ground marker is reached. Each time, it is possible to detect the position coordinates by the positioning using DGPS, even if such ground marker is moved, can be accurately performed position detection, there is an advantage.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a train vehicle position detection system that is an embodiment of the present invention.

FIG. 2 is a first diagram illustrating the operation of the train vehicle position detection system shown in FIG.

FIG. 3 is a second diagram for explaining the operation of the train vehicle position detection system shown in FIG.

FIG. 4 is a third diagram illustrating the operation of the train vehicle position detection system shown in FIG.

5 is a fourth diagram for explaining the operation of the train vehicle position detection system shown in FIG.

FIG. 6 is a fifth diagram illustrating the operation of the train vehicle position detection system shown in FIG.

FIG. 7 is a sixth diagram for explaining the operation of the train vehicle position detection system shown in FIG.

[Explanation of symbols]

1 railroad track 2 railway vehicles 3 reference position stations 11 rails 12 ground markers 20 Vehicle-mounted device 21 Ground marker detector 22 Information Processing Department 23 Information Storage 24 1st antenna 25 Second antenna 26 GPS processing unit 27 Differential receiver 31 transmitting antenna 100 Train own vehicle position detection system G1-Gn GPS satellite

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kimi Sasaki             38-8, Hikarimachi, Kokubunji, Tokyo 38 Foundation             Corporate Railway Technical Research Institute (72) Inventor Isamu Okamoto             38-8, Hikarimachi, Kokubunji, Tokyo 38 Foundation             Corporate Railway Technical Research Institute (72) Inventor Satoshi Nakano             38-8, Hikarimachi, Kokubunji, Tokyo 38 Foundation             Corporate Railway Technical Research Institute (72) Inventor Masako Kamiyama             38-8, Hikarimachi, Kokubunji, Tokyo 38 Foundation             Corporate Railway Technical Research Institute (72) Inventor Nobuo Sugawara             38-8, Hikarimachi, Kokubunji, Tokyo 38 Foundation             Corporate Railway Technical Research Institute F term (reference) 2F029 AA03 AB07 AC02 AC16 AD01                 5H161 AA01 BB03 CC13 DD12 DD23                 5H301 AA03 AA09 BB20 CC03 EE02                       EE12 FF02 FF08 FF11                 5J062 AA01 AA02 AA08 AA13 BB01                       CC07 DD15 DD22 DD24 EE04                       FF00 FF01

Claims (9)

[Claims] 1. A plurality of ground markers installed in the vicinity of a travel path, a mobile object mounting device mounted on a mobile object traveling on the travel path, a reference position station whose position is measured, and an earth. A method of detecting the position of the moving body by the moving body-mounted device using a plurality of orbiting GPS satellites, comprising: a ground marker detecting unit for detecting the ground marker in the moving body-mounted device; GPS information transmitted from the reference position station by radio waves and position correction information transmitted by radio waves from the reference position station, and GPS receiving means for calculating position coordinates based on the GPS information and the position correction information; Means and information processing means are provided, the first traveling of the mobile body is performed, and when the ground marker detecting means detects the ground marker, the information processing means The position coordinates at a point are stored in the information storage means as known marker position coordinates, and when the ground marker detection means detects the ground marker in the second and subsequent traveling of the moving body, The information processing means uses the position coordinates at that time as the current marker position coordinates, searches the information storing means for the known marker position coordinates closest to the current marker position coordinates, and searches the known marker position coordinates. When the relative distance between the position of the search known marker position coordinate and the position of the current marker position coordinate is less than or equal to the error tolerance, A method for detecting a self-position of a moving body, which is characterized in that position coordinates of a known search marker are output. 2. The moving body self-position detecting method according to claim 1, wherein the information processing means is based on contents of the GPS information or the position correction information at the time of the first traveling of the moving body,
Calculating a reception reliability coefficient representing a reception reliability which is a degree of reliability of the GPS information and the position correction information at the time of reception of the ground marker detected by the ground marker detecting means, and the reception reliability coefficient For the ground marker determined that the reception reliability is equal to or higher than the reliability reference value based on the value of, the position coordinates of the ground marker are stored in the information storage unit together with the reception reliability coefficient as the known marker position coordinates. The mobile object characterized by controlling the ground marker for which the reception reliability is determined to be lower than the reliability reference value based on the value of the reception reliability coefficient so as not to store information in the information storage means. Self-position detection method. 3. The mobile body self-position detecting method according to claim 2, wherein the reception reliability coefficient is the number n of the GPS satellites used for receiving the GPS information.
The first term expressing that the reception reliability is higher as n is larger when n is a value of 4 or more, and the rate of decrease in horizontal position accuracy at an observation point on the earth. The second term expressing that the reception reliability is higher as the HDOP is smaller, the latest time when the position correction information is received, and the calculation time of the reception reliability coefficient. It is a function of the differential correction data update time t, which is a time difference, and is a function configured to have at least one of the third terms expressing that the smaller the t is, the higher the reception reliability is. A characteristic method for detecting the self-position of a moving body. 4. The mobile body self-position detecting method according to claim 3, wherein the reception reliability coefficient is obtained by multiplying the sum of the first term and the second term by the third term. A method for detecting the position of a moving body, which is a function. 5. The moving body self-position detecting method according to claim 2, wherein the information processing unit is based on the contents of the GPS information or the position correction information when the moving body travels after the second time. Then, the reception reliability coefficient for the ground marker detected by the ground marker detecting means is calculated, and the current marker reliability, which is the reception reliability at the position of the current marker position coordinate at the time of traveling this time, is the reliability reference. If it is determined that the value is equal to or more than the value, the search known marker reliability that is the reception reliability at the position of the search known marker position coordinate in which the relative distance to the position of the current marker position coordinate is equal to or less than the error allowable value. Of the ground marker detected by the ground marker detecting means when it is determined that the searched known marker reliability is equal to or higher than the current marker reliability. Mobile self-position detecting method and outputs the search known marker coordinates as the position coordinates. 6. The moving body self-position detection method according to claim 5, wherein the information processing unit determines that the current marker reliability is the result of the comparison between the searched known marker reliability and the current marker reliability. When it is determined that it is higher than the search known marker reliability, the current marker position coordinate is output as the position coordinate of the ground marker detected by the ground marker detecting means, and the current marker position coordinate is changed to a new known marker. A mobile body self-position detecting method characterized by storing the position coordinates in the information storage means together with the reception reliability coefficient thereof. 7. The mobile body self-position detecting method according to claim 2, wherein the information processing unit is based on the contents of the GPS information or the position correction information when the mobile body travels after the second time. Then, the reception reliability coefficient for the ground marker detected by the ground marker detecting means is calculated, and the current marker reliability, which is the reception reliability at the position of the current marker position coordinate at the time of traveling this time, is the reliability reference. When it is determined that the value is equal to or larger than the value, the known marker position coordinate closest to the position of the current marker position coordinate is searched from the information storage unit, and the searched known marker that is the searched known marker position coordinate. If the relative distance between the position of the position coordinate and the position of the current marker position coordinate is larger than the error allowable value, the position coordinate of the ground marker detected by the ground marker detecting means. And outputting the current marker position coordinates, and storing the current marker position coordinates as new known marker position coordinates in the information storage means together with the reception reliability coefficient. . 8. The moving body self-position detecting method according to claim 2, wherein the information processing unit is based on contents of the GPS information or the position correction information when the moving body travels after the second time. Then, the reception reliability coefficient for the ground marker detected by the ground marker detecting means is calculated, and the current marker reliability, which is the reception reliability at the position of the current marker position coordinate at the time of traveling this time, is the reliability reference. When it is determined that the value is less than the value, the moving body self-position detecting method is controlled so as not to output the position coordinates of the ground marker detected by the ground marker detecting means. 9. A plurality of ground markers which are installed in the vicinity of a traveling road and whose position is measured in advance and are known, a moving body mounting device mounted on a moving body traveling on the traveling road, and a position A system that has a reference position station being measured and a plurality of GPS satellites that orbit the earth, and in which the mobile body mounting device detects the position of the mobile body, wherein the mobile body mounting device is the ground marker. Ground marker detecting means for detecting the position, GPS information transmitted by radio waves from the GPS satellite, and position correction information transmitted by radio waves from the reference position station, and based on the GPS information and the position correction information. GPS receiving means for calculating position coordinates, information storage means for storing the position coordinates of the ground marker as known marker position coordinates, and the ground marker detecting means. When the upper marker is detected, the position coordinates at that time are set as the current marker position coordinates, and the known marker position coordinates closest to the current marker position coordinates are searched from the information storage means and searched. When the relative distance between the position of the search known marker position coordinate which is the known marker position coordinate and the position of the current marker position coordinate is less than or equal to the error allowable value, the ground marker detected by the ground marker detecting means is detected. A mobile body self-position detection system comprising an information processing means for outputting the search known marker position coordinates as position coordinates.