Information processing device

Abstract

To improve the positioning accuracy of a mobile with an inexpensive configuration.SOLUTION: An information processing device 100 used for positioning a mobile 1 moving along a predetermined route comprises: first positional information acquisition means 101 for acquiring first positional information about the position of the mobile 1 from a receiver 300 of a satellite positioning system 200 boarded on the mobile 1; second positional information acquisition means 102 for acquiring measurement results of an inertial measurement unit 300 boarded on the mobile 1, and second positional information including the speed information about the mobile 1; and computation means 105 for computing a difference between the position of the mobile 1 based on at least one of the first positional information and the second positional information and a reference position along the route when not in a prescribed highly-accurate positioning status. The reference positional information showing the reference position is previously generated using the actual position based on the first positional information and the second positional information that are acquired by moving the mobile 1 along the route multiple times.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an information processing device that is used to measure the position of a mobile object moving along a predetermined route. [Background technology]

[0002] When using a satellite positioning system to position a moving object, there are times when sufficient positioning accuracy cannot be obtained. For example, while a moving object is moving, the communication conditions with the positioning satellite may deteriorate due to the influence of tunnels or surrounding structures, resulting in a discrepancy (position error) between the actual position of the moving object and the position determined using the satellite positioning system. Even if a position error occurs while the moving object is moving and the communication conditions with the positioning satellite improve when the object returns to an open sky environment, the receiver does not have the function to repair the position error (a teleportation-like function that forcibly cancels the position discrepancy), so the effect of the position error remains.

[0003] In response to this, a technique has been proposed in which, when a satellite positioning system is used to determine the position of a moving object, the position of the moving object is corrected by using codes, markers, or the like fixed at multiple positions. Patent Document 1 discloses a technology for correcting the position of an autonomous vehicle using a reference position contained in a position code embedded in a road dividing line when the autonomous vehicle is traveling in a satellite invisible area where it is impossible to receive positioning signals from positioning satellites. Patent document 2 discloses a technology in which a first vehicle position is estimated based on absolute position information acquired from a GNSS, and a second vehicle position is estimated based on relative position information acquired from outside the vehicle (for example, a relative position based on the absolute position of a landmark recognized by an external recognition sensor), and the first vehicle position is corrected based on the difference between the first vehicle position and the second vehicle position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-56740 A [Patent Document 2] JP 2021-188914 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the use of cords or markers fixed at multiple locations requires high installation and maintenance costs.

[0006] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to improve the positioning accuracy of a moving object with an inexpensive configuration. [Means for solving the problem]

[0007] The information processing device of the present invention is an information processing device used to position a mobile body moving along a predetermined route, and is characterized in that it comprises a first position information acquisition means for acquiring first position information regarding the position of the mobile body from a receiver of a satellite positioning system mounted on the mobile body, a second position information acquisition means for acquiring second position information including measurement results of an inertial measurement unit mounted on the mobile body and speed information of the mobile body, and a reference position information generation means for generating reference position information representing a reference position along the route using an actual position based on the first position information and the second position information acquired by moving the mobile body along the route multiple times. In addition, the information processing device of the present invention is an information processing device used to position a mobile body moving along a predetermined route, and comprises a first position information acquisition means for acquiring first position information regarding the position of the mobile body from a receiver of a satellite positioning system mounted on the mobile body, a second position information acquisition means for acquiring second position information including measurement results of an inertial measurement unit mounted on the mobile body and speed information of the mobile body, and a calculation means for calculating the difference between the position of the mobile body based on at least one of the first position information and the second position information when the mobile body is not in a predetermined high-precision positioning state and a reference position along the route, and is characterized in that the reference position information representing the reference position is generated in advance using an actual position based on the first position information and the second position information acquired by moving the mobile body along the route multiple times. Effect of the Invention

[0008] According to the present invention, it is possible to improve the positioning accuracy of a moving object with an inexpensive configuration. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a schematic configuration of a positioning system according to an embodiment; [Diagram 2] 4 is a flowchart showing a process executed by the information processing apparatus according to the embodiment. [Diagram 3] 4 is a flowchart showing a process executed by the information processing apparatus according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, we will explain GNSS (Global Navigation Satellite System). In recent years, the Quasi-Zenith Satellite System "Michibiki" has been used in Japan. Satellite positioning requires four or more positioning satellites, and currently, they are operated in conjunction with other countries' GNSS such as GPS (Global Positioning System). In the future, a seven-satellite system is planned to be established for Michibiki, which means that there will always be four or more Michibiki positioning satellites in the sky above Japan, making it possible for Michibiki to perform positioning on its own. In addition, Michibiki offers a positioning augmentation service that enables highly accurate positioning. This service uses data from electronic reference points located throughout the country to calculate correction information that corrects for errors such as radio wave propagation delays caused by the ionosphere, and based on that, transmits positioning augmentation information from the positioning satellite to accurately determine the current position. By using a compatible receiver, users can achieve centimeter-level high-precision positioning.

[0011] FIG. 1 is a diagram showing a schematic configuration of a positioning system according to an embodiment. In this embodiment, a train 1 running on a track laid on a site for transporting raw materials and the like to various locations in a manufacturing industry is taken as an example of a moving object that moves on a predetermined route and is a positioning target. On the site, there are tunnels through which the train 1 running on the track passes, and structures such as buildings and pipes around the track.

[0012] As shown in FIG. 1, a train 1 is equipped with two receivers 300 and an information processing device 100. The receiver 300 receives information on latitude, longitude, and altitude, and information on satellite time from a positioning satellite using the satellite positioning system 200. In this embodiment, the satellite positioning system 200 includes Michibiki and GPS, but as described above, when positioning is possible using Michibiki alone, only Michibiki may be used. The receiver 300 can receive positioning augmentation information from the positioning satellite, and can perform centimeter-level high-precision positioning. In this embodiment, as described later, the two receivers 300 are operated with the one with the better positioning condition and in standby with the one with the worse condition, and during standby, the power is turned off and then turned on again to reacquire the satellite position and try to improve the positioning accuracy.

[0013] The receiver 300 also includes an inertial measurement unit (IMU) 301. When the train 1 enters a tunnel, travels near a structure, or the like, and communication conditions with the positioning satellite of the satellite positioning system 200 deteriorate, the receiver 300 is configured to be able to estimate the position of the train 1 based on the measurement results of the inertial measurement unit 301, the train 1's vehicle speed pulse, and the forward / backward signal of the train 1. Note that a known technique may be used to estimate the position using the inertial measurement unit, and detailed description thereof will be omitted here. In this way, the receiver 300 is a high-precision positioning terminal compatible with the Centi-meter Level Augmentation Service (CLAS). In addition to satellite positioning, the receiver 300 can perform combined positioning with an INS (autonomous navigation system) using the inertial measurement unit 301, making it possible to continue positioning even in places where radio waves from positioning satellites cannot reach.

[0014] The information processing device 100 is an information processing device used to measure the position of the train 1, and includes a first position information acquisition unit 101, a second position information acquisition unit 102, a reference position information generation unit 103, a judgment unit 104, a calculation unit 105, a decision unit 106, and a receiver control unit 107. The information processing device 100 is configured by a computer including, for example, a CPU, a ROM, a RAM, etc., and the functions of the units 101 to 107 are realized by the CPU executing a predetermined program stored in, for example, the ROM.

[0015] The first location information acquisition unit 101 acquires first location information on the location of the train 1 from the receiver 300. The first location information includes information on latitude, longitude, and altitude received from a positioning satellite, and also includes positioning augmentation information if it has been received from the positioning satellite. Note that the altitude information may be omitted, for example, when there is little change in altitude on the route or when there is no need to measure the change in altitude.

[0016] The second position information acquisition unit 102 acquires second position information including the measurement result of the inertial measurement unit 301 , a train speed pulse which is speed information of the train 1 , and a forward / backward signal of the train 1 .

[0017] The reference position information generating unit 103 generates reference position information representing a reference position along the route using the actual position based on the first position information and the second position information acquired by moving the train 1 along the route multiple times, and stores the generated reference position information in a recording medium (not shown). The process of generating the reference position information will be described later in detail.

[0018] The determining unit 104 determines the positioning state. Five positioning states are defined: FIX, FROAT, DR (Dead Reckoning), independent positioning+DR, and independent positioning. FIX is a state in which communication with the positioning satellites is good, and centimeter-level high-precision positioning is possible using the satellite positioning system 200 by using the positioning augmentation information. FROAT is the state until the estimation of the number of carriers from the positioning satellites is completed. Once this is completed, the positioning accuracy converges to the centimeter level and the state becomes FIX. DR is a state in which communication with the positioning satellite is poor, and the position of train 1 is estimated and located based on second information (measurement results of the inertial measurement unit 301, train 1's speed pulse, and train 1's forward / backward signal). The single point positioning +DR is a state in which the single point positioning is corrected by using second information to perform positioning. The standalone positioning is a state in which positioning is performed using the satellite positioning system 200 without using positioning augmentation information, and the positioning accuracy is about several meters to a dozen meters. In the following, the position of the train 1 measured by FIX, FROAT, and independent positioning will be referred to as the satellite position, and the position of the train 1 measured by DR and independent positioning+DR will be referred to as the estimated position.

[0019] The calculation unit 105 calculates the difference EL between the position of the train 1 based on at least one of the first position information and the second position information when not FIX or FROAT, and the reference position represented by the reference position information stored in a recording medium (not shown). Specifically, when DR, independent positioning+DR, or independent positioning is selected, the calculation unit 105 calculates the difference EL between the estimated position when DR is selected, the estimated position when independent positioning+DR, or the satellite position when independent positioning is selected, and the reference position represented by the reference position information at the closest point.

[0020] When the satellite position is FIX or FROAT, the determination unit 106 determines the satellite position as the position of the train 1. That is, the determination unit 106 determines the position of the train 1 based on the first position information. Furthermore, when the determination unit 106 is in DR, independent positioning+DR, or independent positioning, if the difference EL calculated by the calculation unit 105 is not equal to or greater than a predetermined threshold value EL0, the determination unit 106 determines the estimated position when the determination unit 105 is in DR, the estimated position when the determination unit 105 is in independent positioning+DR, or the satellite position when the determination unit 106 is in independent positioning, as the position of the train 1. That is, the determination unit 106 determines the position of the train 1 based on at least one of the first position information and the second position information. On the other hand, when the determination unit 106 is in DR, independent positioning+DR, or independent positioning, if the difference EL calculated by the calculation unit 105 is equal to or greater than a predetermined threshold value EL0, the determination unit 106 determines the position of the train 1 based on the reference position information. Furthermore, in the case of DR or independent positioning+DR, if it is detected that the train 1 is stopped based on the vehicle speed pulse, the determination unit 106 holds the position of the train 1 before the detection.

[0021] When the difference EL calculated by the calculation unit 105 is equal to or greater than a predetermined threshold value EL0 in DR, independent positioning+DR, or independent positioning, the receiver control unit 107 turns on the power of the standby receiver 300. Then, the receiver control unit 107 selects the satellite position and estimated position of the receiver with the better positioning state from among the two receivers 300. The order of positioning state selection is FIX>FROAT>DR>independent positioning+DR>independent positioning. The receiver control unit 107 also turns off the power of the receiver 300 that was not selected. In independent positioning, fluctuations occur that may become disturbances, and it can be said that it is unsuitable for positioning a train 1 traveling on a track, so DR and independent positioning+DR, which have less fluctuations, are given higher priority than independent positioning.

[0022] Next, the process executed by the information processing device 100 according to the embodiment will be described with reference to FIGS. Fig. 2 is a flowchart showing a process executed by the information processing device 100 according to the embodiment, and shows a process for generating reference position information. The flowchart in Fig. 2 shows a process executed in advance by running the train 1 in order to generate reference position information (hereinafter, referred to as route movement). This route movement differs from the operation (which involves low-speed running and stopping) in which the train 1 transports raw materials and the like to various locations, in that the train 1 does not stop at a position where communication with the positioning satellite is lost, but is preferably performed at a constant vehicle speed.

[0023] In step S1, the first location information acquisition unit 101 acquires first location information from the receiver 300. Furthermore, the second location information acquisition unit 102 acquires second location information.

[0024] In step S2, the reference position information generating unit 103 obtains the actual position of the train 1 at each point, for example, at a constant distance or time interval, based on the first position information and the second position information acquired in step S1. Specifically, the satellite position when FIX or FROAT, the estimated position when DR or independent positioning + DR, or the satellite position when independent positioning is used is set as the actual position of the train 1. If the train 1 travels at a low speed or stops in a tunnel or near a structure, the communication state with the positioning satellite deteriorates and the accuracy of the measurement results of the inertial measurement unit 301 decreases. However, by moving the train 1 along the route, preferably at a constant vehicle speed, without stopping at a position where communication with the positioning satellite is lost, it is possible to obtain the actual position with good positioning accuracy.

[0025] In step S3, the reference position information generating unit 103 judges whether the route movement has reached a predetermined number N (N: a positive number equal to or greater than 2). If the route movement has reached N, the process proceeds to step S4. If the route movement has not reached N, the process returns to step S1.

[0026] In step S4, the reference position information generating unit 103 calculates a cumulative average value of the actual positions at each point using the actual positions acquired by moving along the route N times.

[0027] In step S5, the reference position information generating unit 103 calculates, for each point, a distance L between the cumulative average value calculated in step S4 and the instantaneous value of the train 1, which is the actual position obtained in step S2.

[0028] In step S6, the reference position information generating unit 103 judges whether the distance L calculated in step S5 is less than a predetermined distance L0. If the distance L is less than the predetermined distance L0, the process proceeds to step S7. If the distance L is out of the predetermined range by more than the predetermined distance L0, the process proceeds to step S8.

[0029] In step S7, the reference position information generating unit 103 sets the cumulative average value of the achieved positions calculated in step S4 as the reference position, stores the reference position information representing this reference position in a recording medium (not shown), and ends this flow chart.

[0030] In step S8, the reference position information generating unit 103 removes, as an abnormal value, the actual position of a point where the distance L deviates by a predetermined distance L0 or more. In response to this, in step S4, the reference position information generating unit 103 recalculates the cumulative average value by removing the actual position where the distance L deviates by the predetermined distance L0 or more.

[0031] As described above, reference position information representing a reference position along the route can be generated using an actual position based on the first position information and the second position information obtained by moving the train 1 along the route multiple times.

[0032] FIG. 3 is a flowchart showing a process executed by the information processing device 100 according to the embodiment, and shows a process of locating the position of the train 1 during operation (with low-speed running and stops) in which raw materials and the like are transported to various locations by the train 1.

[0033] In step S11, the first location information acquisition unit 101 acquires first location information, and the second location information acquisition unit 102 acquires second location information.

[0034] In step S12, the determination unit 104 determines whether the positioning state is FIX or FROAT. If the positioning state is FIX or FROAT, the process proceeds to step S13. If the positioning state is not FIX or FROAT but independent positioning+DR or independent positioning due to a non-open sky environment or the like, the process proceeds to step S14.

[0035] In step S13, the determination unit 106 determines the satellite position in FIX or FROAT as the position of the train 1.

[0036] In step S14, the calculation unit 105 calculates the difference EL between the estimated position when DR, the estimated position when single-unit positioning+DR, or the satellite position when single-unit positioning, and the reference position represented by the reference position information at the closest point.

[0037] In step S15, the determination unit 106 determines whether the difference EL calculated in step S14 is equal to or greater than a predetermined threshold value EL0. If the difference EL is equal to or greater than the predetermined threshold value EL0, the process proceeds to step S16. If the difference EL is less than the predetermined threshold value EL0, the process proceeds to step S19. Note that a requirement that EL≧EL0 continues for a certain period of time or more may be added.

[0038] In step S16, the determination unit 106 sets the position of the train 1 as the reference position.

[0039] In step S17, the receiver control section 107 turns on the power of the standby receiver 300 and receives the latitude, longitude and altitude information, satellite time information and positioning augmentation information, if any, from the positioning satellite.

[0040] In step S18, the receiver control unit 107 selects the satellite position and estimated position from the receiver with the better positioning state from among the two receivers 300. As described above, the selection order of positioning states is FIX>FROAT>DR>Standalone positioning+DR>Standalone positioning. The receiver control unit 107 also turns off the power of the receiver 300 that was not selected.

[0041] In step S19, the determination unit 104 determines whether the positioning state is independent positioning. If the positioning state is independent positioning, the process proceeds to step S20. If the positioning state is not independent positioning but is DR or independent positioning+DR, the process proceeds to step S21.

[0042] In step S20, the determination unit 106 determines the satellite position in the single point positioning as the position of the train 1.

[0043] In step S21, the decision unit 106 determines whether the train 1 is stopped. For example, when a vehicle speed pulse is not input for a certain period of time or more, it is determined that the train 1 is stopped. If it is detected that the train 1 has stopped, the process proceeds to step S22. If it is not detected that the train 1 has stopped, the process proceeds to step S23. Here, the situation in which the train 1 is determined to be stopped is when the train 1 is stopped in a tunnel or next to a structure.

[0044] In step S22, the determination unit 106 holds the position of the train 1 before the stop of the train 1 is detected. Even when the train 1 is stopped, the inertial measurement unit 301 cannot be attached and maintained completely horizontally, so that the gravitational acceleration is resolved due to the tilted state, and some acceleration occurs in the horizontal direction, the integral of which becomes large, causing the estimated position to move, which may result in a position error. Therefore, by fixing the position of the train 1 to the position before the stop of the train 1 is detected, the estimated position is prevented from moving when the train 1 is stopped.

[0045] In step S23, the determination unit 106 determines the position estimated by DR or independent positioning+DR as the position of the train 1.

[0046] In step S24, the information processing device 100 determines whether or not an end condition for positioning of the train 1 is satisfied. For example, the end of operation is an end condition for positioning of the train 1. If the end condition is satisfied, this flowchart is ended. If the end condition is not satisfied, the process returns to step S11.

[0047] As described above, when the communication state with the positioning satellite deteriorates due to the influence of a tunnel or surrounding structures while the train 1 is traveling, and a deviation occurs between the actual position of the train 1 and the measured position, the position deviation is automatically detected based on the reference position information generated in advance. In addition, when the train 1 is in a predetermined high-precision positioning state (when the train 1 is in FIX or FROAT), the satellite position is used as the position of the train 1, and when the train 1 is not in a predetermined high-precision positioning state (when the train 1 is in DR, independent positioning + DR, or independent positioning), the train 1 can autonomously select to use the estimated position, satellite position, or reference position as the position of the train 1 according to the difference from the reference position. Furthermore, when the train 1 is not in a predetermined high-precision positioning state, in this embodiment, when the train 1 is in DR, independent positioning + DR, or independent positioning, and the difference from the reference position is large, the receiver 300 in standby can be powered on to select the receiver 300 in a better positioning state, and the first information can be reacquired. Furthermore, the reference position information representing the reference position is generated using an actual position based on the first position information and the second position information obtained by moving the train 1 along the route multiple times, so no equipment or maintenance costs are required and it is less expensive than using codes or markers fixed to multiple positions. In this way, it is possible to improve the positioning accuracy of the train 1 with an inexpensive configuration.

[0048] Although the present invention has been described above with reference to the embodiments, the above embodiments are merely illustrative of the specific examples of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these embodiments. In other words, the present invention can be embodied in various forms without departing from its technical concept or main features. For example, the functions of each of the units 101 to 107 may be realized by a plurality of computer devices. The present invention can also be realized by supplying a program for implementing one or more of the functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions. [Explanation of symbols]

[0049] 1: train, 100: information processing device, 101: first position information acquisition unit, 102: second position information acquisition unit, 103: reference position information generation unit, 104: judgment unit, 105: calculation unit, 106: decision unit, 107: receiver control unit, 200: satellite positioning system, 300: receiver, 301: inertial measurement unit

Claims

1. An information processing device used to measure the position of a moving object moving along a predetermined route, a first position information acquisition means for acquiring first position information relating to a position of the mobile object from a receiver of a satellite positioning system mounted on the mobile object; a second position information acquisition means for acquiring second position information including a measurement result of an inertial measurement unit mounted on the moving body and speed information of the moving body; and a reference position information generation means for generating reference position information representing a reference position along the route using an actual position based on the first position information and the second position information obtained by moving the mobile body along the route multiple times.

2. 2. The information processing apparatus according to claim 1, wherein said reference position information generating means calculates a cumulative average value of said achieved positions and sets this as said reference position.

3. 3. The information processing apparatus according to claim 2, wherein, when the actual position deviates from the cumulative average value by a predetermined distance or more, the reference position information generating means removes the actual position and recalculates the cumulative average value.

4. An information processing device used to measure the position of a moving object moving along a predetermined route, a first position information acquisition means for acquiring first position information relating to a position of the mobile object from a receiver of a satellite positioning system mounted on the mobile object; a second position information acquisition means for acquiring second position information including a measurement result of an inertial measurement unit mounted on the moving body and speed information of the moving body; a calculation means for calculating a difference between a position of the moving object based on at least one of the first position information and the second position information and a reference position along the route when the moving object is not in a predetermined high-precision positioning state, An information processing device characterized in that the reference position information representing the reference position is generated in advance using an actual position based on the first position information and the second position information obtained by moving the mobile body along the route multiple times.

5. determining a position of the moving object based on the first position information when the moving object is in the predetermined high-accuracy positioning state; The information processing device according to claim 4, further comprising a determination means for determining the position of the moving body based on at least one of the first position information and the second position information if the difference is not equal to or greater than a predetermined threshold when the predetermined high-precision positioning state is not being maintained, and for determining the position of the moving body based on the reference position information if the difference is equal to or greater than the predetermined threshold.

6. The mobile object is equipped with a plurality of the receivers, 6. The information processing apparatus according to claim 4, further comprising a receiver control means for turning on the power of the receiver in standby mode if the difference is equal to or greater than a predetermined threshold value when the predetermined high-precision positioning state is not reached.

7. The information processing apparatus according to claim 5 , wherein, when the predetermined high-precision positioning state is not in effect and the stoppage of the moving object is detected, the determination means holds the position of the moving object before the detection.

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