Train autonomous differential positioning method and system based on transponder

Abstract

The invention discloses a train autonomous differential positioning method and system based on transponders, and the method comprises the steps: when a train passes through at least one transponder, a vehicle-mounted device located on the train reads a message of the transponder, and obtains the geographic coordinate values Pbalise (Xbalise, Ybalise and Zbalise) of the transponder; wherein Xbalise is the longitude of the transponder, Ybalise is the latitude of the transponder, and Zbalise is the elevation of the transponder; measuring the time when the navigation message is transmitted from at least four satellites to the vehicle-mounted equipment, and calculating the transmission distance to obtain a pseudo-range value rho i between the vehicle-mounted equipment and the ith satellite; calculating an actual distance Di between the transponder and each satellite according to the geographic coordinate value Pbalise of the transponder, and calculating a pseudo-range differential correction delta rhoi = Di-rhoi of each satellite; and based on the pseudo-range value rho i and the pseudo-range differential correction delta rho i, listing a pseudo-range calculation equation set and solving an actual coordinate P (X, Y, Z) of the vehicle-mounted equipment to finish train positioning. The method not only reduces the operation and maintenance cost, but also improves the satellite positioning precision of the train.

Description

Technical Field

[0001] The present invention relates to the field of train control, and in particular to a transponder-based train autonomous differential positioning method and system. Background Art

[0002] In the train operation control system, train positioning is a core safety function that directly affects the safety and availability of the overall train control system. Errors in train positioning will lead to catastrophic consequences such as collisions and derailments.

[0003] The Global Navigation Satellite System (GNSS) is an airborne radio navigation and positioning system that can provide users with all-weather three-dimensional coordinates, speed and time information at any location on the Earth's surface or in near-Earth space. The Beidou Satellite Navigation System (BDS) is a global satellite navigation system independently developed by China. The train control system based on Beidou satellites to achieve autonomous train positioning is a key component of my country's intelligent railway technology system. It can greatly reduce the trackside train positioning equipment and has typical advantages such as flexible engineering configuration, low investment, and less maintenance. In the train autonomous positioning train control system based on Beidou satellites, the on-board equipment has the function of detecting train speed, travel distance, and movement direction. It can also integrate satellite positioning, speed sensors, transponders and other information to achieve a multi-source fusion positioning function for trains that meets the safety and reliability requirements of train operation control.

[0004] Among them, the existing train positioning includes the following methods: (1) Speed ​​measurement positioning is a continuous positioning method, which achieves positioning by measuring the real-time running speed of the train and calculating the running distance of the train. The positioning accuracy is usually ±10m in each interval, but the error will accumulate over time. (2) Transponder positioning is an intermittent positioning method, which uses electromagnetic induction technology to transmit information between the ground and the vehicle at a specific location. The positioning accuracy is high (less than 0.3m), but it must be combined with other positioning technologies to achieve continuous positioning. (3) Satellite single-point positioning is a continuous positioning method that achieves autonomous positioning by receiving navigation messages sent by satellites, but the positioning accuracy is easily affected by error factors such as the propagation path and the receiver itself, making its positioning accuracy low and unable to meet the high-precision positioning requirements of the train control system.

[0005] Therefore, in the train control system, it is necessary to use differential technology to estimate the common error from the ground differential reference station with a known position, and weaken or eliminate some errors through relevant compensation algorithms to improve positioning accuracy. Therefore, it is necessary to continuously set up a corresponding number of ground differential reference stations along the railway and build a corresponding communication network to send differential information to the mobile station, that is, the train control on-board equipment installed on the train, through a wireless network in real time to meet the needs of real-time safety control of the train. If there is no existing differential system available near the railway, a new differential system needs to be built, which has huge investment, construction and maintenance costs.

[0006] The statements herein merely provide background art related to the present invention and do not necessarily constitute prior art. Summary of the invention

[0007] The purpose of the present invention is to provide a method and system for autonomous differential positioning of trains based on transponders, which uses autonomous differential technology implemented by existing transponders on railway lines to reduce the project investment and operation and maintenance costs of setting up ground differential reference stations, while improving the satellite positioning accuracy of trains and reducing the computing burden of on-board equipment.

[0008] In order to achieve the above objectives, the present invention provides a train autonomous differential positioning method based on a transponder, which comprises: when a train passes through at least one transponder, an on-board device located on the train reads a message from the transponder and obtains a geographic coordinate value P of the transponder. balise (X balise ,Y balise ,Z balise ), where X balise is the longitude of the transponder, Y balise is the latitude of the transponder, Z balise is the altitude of the transponder; measuring the time for the navigation message to be transmitted from at least four satellites to the vehicle-mounted device and calculating the propagation distance, and obtaining the pseudo-range value ρ between the vehicle-mounted device and the i-th satellite i , i is the satellite number; according to the geographic coordinate value P of the transponder balise , calculate the actual distance D between the transponder and each satellite i , and calculate the pseudorange differential correction Δρ of each satellite i =D i -ρ i Based on the pseudorange value ρ i and pseudorange differential correction Δρ i , list the pseudo-range calculation equations and solve the actual coordinates P(X,Y,Z) of the on-board equipment to complete the train positioning.

[0009] Optionally, from the time the train starts running until it passes the first balise, the on-board equipment sets the differential correction number to an invalid state.

[0010] Optionally, if the vehicle-mounted device does not read the message of the transponder, the validity state of the differential correction number is set according to a judgment condition.

[0011] Optionally, the judgment condition includes: judging whether the distance between the current position of the vehicle-mounted device and the position where a valid differential correction number was last obtained exceeds the maximum effective distance of the configured differential correction point; if it exceeds the maximum effective distance, setting the differential correction number to an invalid state; if it does not exceed the maximum effective distance, setting the differential correction number to a valid state.

[0012] Optionally, the maximum effective distance does not exceed 10 km.

[0013] Optionally, the navigation message includes at least satellite coordinates and delay errors.

[0014] Optionally, the calculation of the actual distance D between the geographic coordinate value of the transponder and each satellite i The calculation formula is as follows:

[0015]

[0016] Among them, Q i (X i ,Y i ,Z i ) are the satellite coordinates obtained from each corresponding satellite.

[0017] Optionally, the pseudo-range value ρ between the vehicle-mounted device and the i-th satellite i The calculation formula is as follows:

[0018]

[0019] Where c is the speed of light, is the time when the navigation message is sent from the satellite, The time when the vehicle-mounted device receives the navigation message.

[0020] Optionally, the pseudorange calculation equation group is expressed as follows:

[0021]

[0022] Where c is the speed of light, Δt is the clock error of the onboard equipment, and ε i is the delay error caused by the ionosphere and troposphere corresponding to the navigation message of the i-th satellite, Q i (X i ,Y i ,Z i ) are the satellite coordinates obtained from the corresponding satellite.

[0023] Optionally, the train autonomous differential positioning method further comprises: when the on-board device reads the message of the transponder, determining whether the message contains the geographic coordinate value P balise (X balise ,Y balise ,Z balise ), if included, the pseudorange differential correction number is calculated; if not included, the message of the next transponder is re-read.

[0024] Optionally, the time for the train to run from the current balise to the next balise and obtain the real-time pseudorange differential correction number does not exceed 10 minutes.

[0025] Optionally, completing the train positioning includes: matching the actual coordinates P (X, Y, Z) of the on-board equipment with the train electronic map to determine the position of the train on the railway line.

[0026] The present invention also provides a transponder-based train autonomous differential positioning system, which is applicable to the above-mentioned train autonomous differential positioning method, comprising: a vehicle-mounted device, which is arranged on the train; the vehicle-mounted device is provided with a transponder antenna for reading the transponder message and calculating the pseudo-range differential correction number Δρ i ; Several transponders are arranged at intervals along the railway line; each of the transponders stores at least mileage information and geographic coordinate information; the geographic coordinate information includes the geographic coordinate value P corresponding to the transponder balise (X balise ,Y balise ,Z balise ), where X balise is the longitude of the transponder, Y balise is the latitude of the transponder, Z balise is the altitude of the transponder; a satellite system comprising at least four satellites, each of which is in communication with the vehicle-mounted device and is used to transmit navigation messages to the vehicle-mounted device to calculate the pseudo-range value ρ between the vehicle-mounted device and the i-th satellite i , i is the satellite number.

[0027] Optionally, the distance between two adjacent transponders is less than or equal to 10 km.

[0028] Optionally, the mileage information of the transponder includes at least: a distance / length resolution and a kilometer mark at the transponder installation location.

[0029] Compared with the prior art, the train autonomous differential positioning method and system based on balise provided by the present invention utilizes the existing balise 102 in the train control system and does not require differential systems such as differential reference stations, thereby significantly reducing project investment and operation and maintenance costs. i When the distance between two adjacent balises 102 is within 10 km, the positioning accuracy requirement of the train control system is still met, and the cumulative error of train positioning can be continuously eliminated between two adjacent balises 102;

[0030] Furthermore, compared with the existing train control system based on satellite positioning, the distance between the ground differential reference station and the train varies greatly with the operation of the train, which in turn causes the differential positioning accuracy to fluctuate. In the present invention, since the interval between two adjacent transponders 102 is short and certain, the satellite positioning accuracy of the train is relatively more stable. At the same time, compared with the existing train control system based on satellite positioning that requires transponders to be installed every 6 km on the line, the layout density of the transponders on the line can be further reduced, saving investment.

[0031] The autonomous differential technology based on the transponder 102 provided by the present invention does not rely on the differential system and the related differential information transmission network. The overall structure of the train autonomous differential positioning system is simple, and the on-board equipment 101 has a low computing burden, which can make the availability and stability of the satellite-based autonomous positioning function better. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of train satellite positioning based on ground differential reference stations;

[0033] Figure 2 It is a schematic diagram of the circuit of the train autonomous differential positioning system based on the balise of the present invention;

[0034] Figure 3 The present invention is a flow chart of the balise-based train autonomous differential positioning method. DETAILED DESCRIPTION

[0035] The following is a further detailed description of the autonomous differential positioning method and system for trains based on transponders proposed in the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purposes, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope of the technical content disclosed in the present invention.

[0036] In the existing train control system, the satellite positioning of trains based on differential reference stations requires the use of differential technology to estimate the common error from the ground differential reference stations with known positions. Figure 1As shown, the differential positioning technology in the existing GNSS (Global Navigation Satellite System) can be divided into three types according to the different information modes sent by the ground differential reference station 1: position differential, pseudorange differential and carrier phase differential. Specifically, the ground differential reference station 1 can calculate the differential correction number caused by errors such as orbit and clock errors of the satellite 3, atmospheric influence, and multipath effect based on its own precise coordinates. The ground differential reference station 1 sends the differential correction number through wireless communication, which is received by the mobile station 2 (i.e., the on-board equipment on the train). The on-board equipment corrects the coordinates of the user station (i.e., the train) solved in real time, and obtains the accurate coordinate value after differential correction to achieve safe positioning of the train.

[0037] As can be seen from the above, differential reference information (i.e., differential correction number) plays a decisive role in correcting satellite positioning errors and improving positioning accuracy. In principle, the coverage of the ground differential reference station 1 should be distributed as evenly as possible according to the shape, size and usage requirements of the target area, so that the entire area can receive high-quality differential signals, reduce signal blind spots, and ensure high error correlation. However, this requires the continuous establishment of differential reference stations along the railway and the construction of corresponding communication networks. If there is no existing differential system available near the railway, a new differential system needs to be built, and the investment, construction and maintenance costs are huge.

[0038] Based on the above defects, the present invention proposes a train autonomous differential positioning system 100 that does not rely on various traditional satellite differential systems and is only based on existing transponder devices, such as Figure 2 As shown, it includes: an on-board device 101, which is arranged on the train; the on-board device 101 is provided with a transponder antenna (not shown in the figure), which is used to read the message of the transponder 102 and calculate the pseudo-range differential correction number Δρ i ; A plurality of transponders 102 are arranged at intervals along the railway line; each of the transponders 102 stores at least mileage information and geographic coordinate information; the geographic coordinate information includes the geographic coordinate value P corresponding to the transponder balise (X balise ,Y balise ,Z balise ), which is the WGS-84 geodetic coordinate system; the X in the geographic coordinate value balise is the longitude of the transponder, Y balise is the latitude of the transponder, Z balise is the elevation of the transponder; the mileage information of the transponder 102 includes at least: the distance / length resolution and the kilometer mark at the transponder installation location; the satellite system 103, which includes at least four satellites 131, each satellite 131 is connected to the vehicle-mounted device 101 for transmitting navigation messages to the vehicle-mounted device 101 to calculate the pseudo-range value ρ between the vehicle-mounted device 101 and the i-th satellite 131 i, i is the satellite number. The number of satellites 131 is no less than 4, because the pseudo-range between the vehicle-mounted device 101 and the satellite 131 is composed of the real distance and the clock error, that is, it includes the three-dimensional coordinates x, y, z and the clock error, a total of 4 unknown quantities, and at least four satellites are required to list four pseudo-range calculation equations to solve the pseudo-range value.

[0039] The train autonomous differential positioning system 100 based on the transponder provided by the present invention adds the geographic coordinate information of the actual installation location of the transponder in the transponder 102, and calculates the pseudo-range value ρ according to the geographic coordinate information. i and pseudorange differential correction Δρ i , lists the pseudorange calculation equations and solves the actual coordinates P(X, Y, Z) of the vehicle-mounted device 101, realizing the autonomous differential technology based on the transponder, which does not rely on the differential system and the related differential information transmission network. The overall structure of the system is simple, and the computational burden of the vehicle-mounted equipment is low, which can make the availability and stability of the satellite-based autonomous positioning function better.

[0040] Among them, the number and installation position of the transponder 102 can be reasonably arranged according to the train positioning accuracy requirements, the train autonomous differential principle and the line conditions. Furthermore, in order to ensure the positioning accuracy of the train and based on the consideration of high precision requirements, the distance between two adjacent transponders 102 is less than or equal to 10km. This is because when the distance between the on-board equipment 101 and the transponder 102 is less than or equal to 10km, the correction effect on the ionosphere or stratosphere is best, and the positioning accuracy can reach the sub-meter level (0.5-1 meter), achieving more accurate train positioning. At the same time, compared with the existing satellite positioning-based train control system, which requires transponders to be set every 6km on the line, the layout density of transponders on the railway line can be further reduced, saving investment.

[0041] Based on the transponder-based train autonomous differential positioning system 100 in the above embodiment, the present invention further provides a transponder-based train autonomous differential positioning method, which comprises: when the train passes through at least one transponder 102, the on-board device 101 located on the train reads the message of the transponder 102 and obtains the geographic coordinate value P of the transponder 102 balise (X balise ,Y balise ,Z balise ), where X balise is the longitude of the transponder, Y balise is the latitude of the transponder, Z balise is the elevation of the transponder; according to the principle of satellite positioning, by measuring the time it takes for the navigation message to be transmitted from at least four satellites to the vehicle-mounted device 101 and calculating the propagation distance, the pseudo-range value ρ between the vehicle-mounted device and the i-th satellite is obtained i, i is the satellite number; the navigation message at least includes the satellite coordinates and the delay error; according to the geographic coordinate value P of the transponder 102 balise , calculate the actual distance D between the transponder 102 and each satellite 131 i , and calculate the pseudo-range differential correction Δρ of each satellite 131 i =D i -ρ i Based on the pseudorange value ρ i and pseudorange differential correction Δρ i , list the pseudo-range calculation equations and solve the actual coordinates P (X, Y, Z) of the on-board device 101 to complete the train positioning.

[0042] The train autonomous differential positioning method based on the transponder provided by the present invention calculates the pseudo-range value ρ according to the geographic coordinate information i and pseudorange differential correction Δρ i , the pseudo-range calculation equations are listed and the actual coordinates P(X, Y, Z) of the on-board device 101 are solved. This method utilizes the existing transponder equipment in the train control system and does not set up differential systems such as ground differential reference stations, which greatly reduces project investment and operation and maintenance costs, while improving the positioning accuracy of the train.

[0043] Specifically, the pseudo-range value ρ between the vehicle-mounted device 101 and the i-th satellite 131 is i The calculation formula is as follows:

[0044]

[0045] Where c is the speed of light, is the time when the navigation message is sent from the satellite, The time when the vehicle-mounted device receives the navigation message.

[0046] Specifically, the actual distance D between the geographic coordinate value of the transponder 102 and each satellite 131 is calculated. i The calculation formula is as follows:

[0047]

[0048] Among them, Q i (X i ,Y i ,Z i ) are the satellite coordinates obtained from each corresponding satellite.

[0049] Specifically, based on the pseudorange value ρ i and pseudorange differential correction Δρ i , the expression of the pseudorange calculation equation group is as follows:

[0050]

[0051] Where c is the speed of light, Δt is the clock error of the onboard equipment, and ε i is the delay error caused by the ionosphere and troposphere corresponding to the navigation message of the i-th satellite, Q i (X i ,Y i ,Z i ) are satellite coordinates obtained from the corresponding satellite. The actual coordinates P(X, Y, Z) of the vehicle-mounted device 101 can be obtained by solving the above pseudo-range calculation equations.

[0052] Furthermore, based on the actual coordinates P (X, Y, Z) of the on-board device 101 obtained, the actual coordinates P (X, Y, Z) of the on-board device 101 are matched with the electronic map of the train, so that the position of the train on the railway line can be determined, thereby realizing autonomous differential positioning of the train, improving the positioning accuracy of the train, and reducing the real-time satellite positioning error.

[0053] In a specific embodiment, if Figure 3 As shown, the train autonomous differential positioning method based on balise includes:

[0054] S1. The train starts running, i.e. the on-board device 101 starts running; wherein, when the train starts running and before it passes the first transponder 102, the on-board device 101 sets the differential correction number to an invalid state; this is because the on-board device 101 cannot read the geographic coordinate value stored in the transponder 102. At this time, the train is actually processed as non-differential, and the horizontal and elevation positioning errors are usually around ±10 meters.

[0055] S2, when the train passes a transponder 102, the onboard device 101 on the train reads the message of the transponder. If the onboard device 101 reads the message of the transponder 102, step S3 is executed;

[0056] S3, judging whether the message contains the geographic coordinate value P balise (X balise ,Y balise ,Z balise ), if included, the pseudorange differential correction number is calculated; if not included, the message of the next transponder 102 is re-read.

[0057] S4. Calculate the pseudo-range differential correction number according to the geographic coordinate value and real-time positioning; specifically including:

[0058] S41, calculating the pseudo-range value ρ between the vehicle-mounted device 101 and the i-th satellite 131 i ;

[0059] S42, calculating the actual distance D between the geographic coordinate value of the transponder 102 and each satellite 131 i ;

[0060] S43, calculate the pseudo-range differential correction Δρ of each satellite 131 i .

[0061] S5, based on the pseudorange value ρ i and pseudorange differential correction Δρ i , list the pseudo-range calculation equations and solve the actual coordinates P(X,Y,Z) of the on-board equipment to complete the train positioning and reduce the satellite real-time positioning error.

[0062] Further, in step S2, if the vehicle-mounted device 101 does not read the message of the transponder, the validity state of the differential correction number is set according to the judgment condition.

[0063] Among them, the judgment condition includes: judging whether the distance between the current position of the vehicle-mounted device 101 and the position where a valid differential correction number was obtained most recently exceeds the maximum effective distance of the configured differential correction point; if it exceeds the maximum effective distance, setting the differential correction number to an invalid state; if it does not exceed the maximum effective distance, setting the differential correction number to a valid state.

[0064] As an optional embodiment, the maximum effective distance does not exceed 10 km. This is because if it exceeds 10 km, the pseudo-range differential correction number Δρ stored in the vehicle-mounted device 101 i , the condition for eliminating the error will not be met, the vehicle-mounted device 101 will reset the differential correction number to an invalid state, that is, there is no available differential information, then return to step S2, and re-read the message of the next transponder 102, repeat steps S3 to S4, and calculate the pseudorange value ρ i and pseudorange differential correction Δρ i , list the pseudo-range calculation equations and solve the actual coordinates P(X,Y,Z) of the on-board equipment to complete the train positioning.

[0065] Among them, if the vehicle-mounted device 101 runs from the current transponder 102 to the next transponder 102, because the distance between two adjacent transponders is small (no more than 10 km), the pseudo-range differential correction Δρ obtained by the vehicle-mounted device 101 from the previous transponder 102 is i It can still be regarded as real-time and effective, and can still be used to make real-time corrections to the current positioning. In a specific embodiment, based on the high-precision requirement, the train running speed is 80km / h, the distance between two adjacent transponders is 10km, and when the train runs to the next transponder and obtains the real-time pseudo-range differential correction Δρ iIt does not exceed 10 minutes, and the differential lag during this period can be ignored, so as to realize real-time correction of the accumulated positioning error of the train within the line range between the two balises, thereby obtaining the ideal train positioning accuracy.

[0066] In summary, the train autonomous differential positioning method and system based on balise provided by the present invention utilizes the existing balise 102 in the train control system and does not require differential systems such as differential reference stations, thereby significantly reducing project investment and operation and maintenance costs. i When the distance between two adjacent balises 102 is within 10 km, the positioning accuracy requirement of the train control system is still met, and the cumulative error of train positioning can be continuously eliminated between two adjacent balises 102;

[0067] Furthermore, compared with the existing train control system based on satellite positioning, the distance between the ground differential reference station and the train varies greatly with the operation of the train, which in turn causes the differential positioning accuracy to fluctuate. In the present invention, since the interval between two adjacent transponders 102 is short and certain, the satellite positioning accuracy of the train is relatively more stable. At the same time, compared with the existing train control system based on satellite positioning that requires transponders to be installed every 6 km on the line, the layout density of the transponders on the line can be further reduced, saving investment.

[0068] The autonomous differential technology based on the transponder 102 provided by the present invention does not rely on the differential system and the related differential information transmission network. The overall structure of the train autonomous differential positioning system is simple, and the on-board equipment 101 has a low computing burden, which can make the availability and stability of the satellite-based autonomous positioning function better.

[0069] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0070] In the description of the present invention, it should be understood that the terms "center", "height", "thickness", "up", "down", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0071] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0073] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A train autonomous differential positioning method based on a balise, characterized in that: include: When a train passes by at least one transponder, the onboard equipment on the train reads the message of the transponder and obtains the geographic coordinate value P of the transponder. balise (X balise ,Y balise ,Z balise ), where X balise is the longitude of the transponder, Y balise is the latitude of the transponder, Z balise is the elevation of the transponder; Measure the time it takes for the navigation message to be transmitted from at least four satellites to the vehicle-mounted device and calculate the propagation distance to obtain the pseudo-range value ρ between the vehicle-mounted device and the i-th satellite i , i is the satellite number; According to the geographic coordinate value P of the transponder balise , calculate the actual distance D between the transponder and each satellite i , and calculate the pseudorange differential correction Δρ of each satellite i =D i -ρ i ; Based on the pseudorange value ρ i and pseudorange differential correction Δρ i , list the pseudo-range calculation equations and solve the actual coordinates P(X,Y,Z) of the on-board equipment to complete the train positioning.

2. The train autonomous differential positioning method according to claim 1, characterized in that: From the time the train starts running until it passes the first balise, the on-board equipment sets the differential correction number to an invalid state.

3. The train autonomous differential positioning method according to claim 2, characterized in that: If the vehicle-mounted device does not read the message of the transponder, the validity state of the differential correction number is set according to the judgment condition.

4. The train autonomous differential positioning method according to claim 3, characterized in that: The judgment condition includes: judging whether the distance between the current position of the vehicle-mounted device and the position where a valid differential correction number was obtained most recently exceeds the maximum effective distance of the configured differential correction point; if it exceeds the maximum effective distance, setting the differential correction number to an invalid state; if it does not exceed the maximum effective distance, setting the differential correction number to a valid state.

5. The train autonomous differential positioning method according to claim 4, characterized in that: The maximum effective distance does not exceed 10km.

6. The train autonomous differential positioning method according to claim 1, characterized in that: The navigation message at least includes satellite coordinates and delay errors.

7. The train autonomous differential positioning method according to claim 6, characterized in that: The actual distance D between the geographic coordinates of the transponder and each satellite is calculated. i The calculation formula is as follows: Among them, Q i (X i ,Y i ,Z i ) are the satellite coordinates obtained from each corresponding satellite.

8. The train autonomous differential positioning method according to claim 6, characterized in that: The pseudo-range value ρ between the vehicle-mounted device and the i-th satellite i The calculation formula is as follows: Where c is the speed of light, is the time when the navigation message is sent from the satellite, The time when the vehicle-mounted device receives the navigation message.

9. The train autonomous differential positioning method according to claim 6, characterized in that: The pseudorange calculation equations are expressed as follows: Where c is the speed of light, Δt is the clock error of the onboard equipment, and ε i is the delay error caused by the ionosphere and troposphere corresponding to the navigation message of the i-th satellite, Q i (X i ,Y i ,Z i ) are the satellite coordinates obtained from the corresponding satellite.

10. The train autonomous differential positioning method according to claim 1, characterized in that: Also includes: When the vehicle-mounted device reads the message from the transponder, it determines whether the message contains the geographic coordinate value P balise (X balise ,Y balise ,Z balise ), if included, the pseudorange differential correction number is calculated; if not included, the message of the next transponder is re-read.

11. The train autonomous differential positioning method according to claim 1, characterized in that: The time for the train to run from the current balise to the next balise and obtain the real-time pseudo-range differential correction number shall not exceed 10 minutes.

12. The train autonomous differential positioning method according to claim 1, characterized in that: The train positioning includes: matching the actual coordinates P (X, Y, Z) of the on-board equipment with the train electronic map to determine the position of the train on the railway line.

13. A train autonomous differential positioning system based on a balise, applicable to the train autonomous differential positioning method according to any one of claims 1 to 12, characterized in that: include: The on-board device is arranged on the train; the on-board device is provided with a transponder antenna for reading the transponder message and calculating the pseudo-range differential correction number Δρ i ; A plurality of transponders are arranged at intervals along the railway line; each of the transponders stores at least mileage information and geographic coordinate information; the geographic coordinate information includes the geographic coordinate value P corresponding to the transponder balise (X balise ,Y balise ,Z balise ), where X balise is the longitude of the transponder, Y balise is the latitude of the transponder, Z balise is the elevation of the transponder; A satellite system comprising at least four satellites, each of which is in communication with the vehicle-mounted device and is used to transmit navigation messages to the vehicle-mounted device to calculate the pseudo-range value ρ between the vehicle-mounted device and the i-th satellite i , i is the satellite number.

14. The train autonomous differential positioning system according to claim 13, characterized in that: The distance between two adjacent transponders is less than or equal to 10 km.

15. The train autonomous differential positioning system according to claim 13, characterized in that: The mileage information of the transponder includes at least: distance / length resolution and kilometer mark at the transponder installation location.

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