Positioning method, work vehicle and positioning system

Abstract

To provide a positioning method, a work vehicle and a positioning system capable of preventing switching of a base station when positioning a mobile body on the basis of correction information corresponding to the specific base station.SOLUTION: While RTK positioning for calculating a position of a work vehicle 10 is possible on the basis of first correction information generated on the basis of satellite signals received from a satellite by one base station, a positioning device 14 does not execute RTK positioning on the basis of second correction information generated on the basis of satellite signals received from a satellite by another base station.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a positioning device that calculates the current position of a moving object and the like.

Background Art

[0002] Conventionally, a real-time kinematic method (RTK-GPS positioning method, hereinafter referred to as "RTK method") capable of highly accurately positioning a work vehicle such as a tractor has been known. According to the RTK method, highly accurate positioning can be achieved by using correction information corresponding to a base station (reference station) close to the work vehicle.

[0003] Also, as another positioning method, a VRS (Virtual Reference Station) method is known. For example, Patent Document 1 discloses a technique of generating VRS reference information of an antenna station (Ak: A1 to An) by using satellite observation information from fixed base stations (R1 to R4) and transmitting the generated VRS reference information to a mobile station by a VRS information broadcast center.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional technology, since the base station closest to the work vehicle is selected and the current position of the work vehicle is calculated using the correction information corresponding to the base station, for example, when there is a farm field where the work vehicle works at an intermediate point between two base stations, there is a possibility that the base station corresponding to the correction information will be switched while the work vehicle is autonomously traveling in the farm field. When the base station is switched while the work vehicle is autonomously traveling, there arises a problem that the positioning by the RTK method is temporarily interrupted and the autonomous traveling of the work vehicle is interrupted. This problem is not limited to work vehicles that autonomously travel in farm fields, and can similarly occur in various systems that position a moving object using correction information.

[0006] An object of the present invention is to provide a positioning method, a work vehicle, and a positioning system capable of preventing switching of a base station when positioning a moving object based on correction information corresponding to a specific base station.

Means for Solving the Problems

[0007] The positioning method according to the present invention is a positioning method in which, while a specific positioning capable of calculating the position of a moving object based on first correction information generated based on satellite signals received by one base station from satellites is possible, another base station does not execute the specific positioning based on second correction information generated based on satellite signals received by the other base station from the satellites.

[0008] The work vehicle according to the present invention is a work vehicle that travels in a farm field as the moving object, and includes a positioning device that positions the work vehicle by the positioning method, and a control device that executes a traveling process based on position information calculated by the positioning device.

[0009] The positioning system according to the present invention does not execute the specific positioning based on second correction information generated based on satellite signals received by another base station from the satellites while a specific positioning capable of calculating the position of a moving object based on first correction information generated based on satellite signals received by one base station from the satellites is possible.

Effects of the Invention

[0010] According to the present invention, when positioning a mobile body based on correction information corresponding to a specific base station, it is possible to provide a positioning method, a work vehicle, and a positioning system that can prevent switching of the base station.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] The following embodiments are an example of embodying the present invention and do not limit the technical scope of the present invention.

[0013] As shown in FIG. 1, the positioning system 1 according to the embodiment of the present invention includes a work vehicle 10, a base station server 20, a base station 30, and a satellite 40. The work vehicle 10 and the base station server 20 can communicate via a communication network N1 (see FIG. 2) such as a mobile phone line network, a packet line network, or a wireless LAN.

[0014] In this embodiment, the case where the work vehicle 10 is a tractor will be described as an example. As another embodiment, the work vehicle 10 may be a rice transplanter, a combine, a construction machine, a snowplow, or the like. The work vehicle 10 is configured to be able to autonomously travel (automatically travel) along a travel route within the farm field F (see FIG. 4). For example, the work vehicle 10 can autonomously travel along a travel route generated in advance for the farm field F based on the position information of the current position of the work vehicle 10 calculated by the positioning system 1. The work vehicle 10 is an example of the moving body of the present invention.

[0015] The satellite 40 is a positioning satellite that constitutes a satellite positioning system such as GNSS (Global Navigation Satellite System), and transmits GNSS signals (satellite signals). The positioning system 1 includes a plurality of satellites 40. The base station 30 is a reference point (reference station) that constitutes a satellite positioning system, and is installed at a plurality of locations in advance. In the present embodiment, two base stations 30A and 30B are exemplified. The base station server 20 is a management server that manages a plurality of base stations 30, and transmits correction information for calculating the current position of the work vehicle 10 to the work vehicle 10. The base station 30A is an example of the first base station of the present invention, and the base station 30B is an example of the second base station of the present invention.

[0016] The work vehicle 10 executes a positioning process for calculating the current position (latitude and longitude) of the work vehicle 10 based on the GNSS signal transmitted from the satellite 40 and the correction information transmitted from the base station server 20. Here, in the present embodiment, the positioning system 1 positions the work vehicle 10 using a positioning method of the RTK system. Since the positioning method by the RTK system is a well-known method, a detailed description is omitted, and only an outline is described below. For example, when the work vehicle 10 receives a GNSS signal from the satellite 40, the work vehicle 10 calculates its position (single positioning) based on the GNSS signal. The base station server 20 generates correction information for correcting the position based on the positioning information (such as GNSS signals) obtained from the base station 30 closest to the work vehicle 10. The positioning system 1 corrects the calculated position of the work vehicle 10 based on the correction information, and calculates the current position of the work vehicle 10. The work vehicle 10 autonomously travels along the travel route while acquiring the current position within the farm field F.

[0017] [Work vehicle 10] As shown in FIGS. 2 and 3, the work vehicle 10 includes a vehicle control device 11, a traveling device 12, a working device 13, a positioning device 14, and the like. The vehicle control device 11 is electrically connected to the traveling device 12, the working device 13, the positioning device 14, and the like. Note that the vehicle control device 11 and the positioning device 14 may be capable of wireless communication.

[0018] The vehicle control device 11 is a computer system including one or more processors and a storage memory such as a non-volatile memory and a RAM. Then, the vehicle control device 11 controls the operation of the work vehicle 10 according to various user operations on the work vehicle 10. Further, the vehicle control device 11 executes autonomous driving processing of the work vehicle 10 based on the current position of the work vehicle 10 calculated by a positioning device 14 described later and a pre-generated travel route (see FIG. 4). The vehicle control device 11 is an example of the control device of the present invention, and the autonomous driving processing is an example of the driving processing of the present invention. The travel route is stored in the work vehicle 10 or a server (not shown) that manages the work vehicle 10.

[0019] The traveling device 12 is a driving unit that causes the work vehicle 10 to travel. As shown in FIG. 3, the traveling device 12 includes an engine 121, front wheels 122, rear wheels 123, a transmission 124, a front axle 125, a rear axle 126, a steering wheel 127, and the like. The front wheels 122 and the rear wheels 123 are respectively provided on the left and right sides of the work vehicle 10. Further, the traveling device 12 is not limited to a wheel type including the front wheels 122 and the rear wheels 123, and may be a crawler type including crawlers provided on the left and right sides of the work vehicle 10.

[0020] The engine 121 is a drive source such as a diesel engine or a gasoline engine that is driven using fuel supplied from a fuel tank (not shown). The traveling device 12 may include an electric motor as a drive source together with the engine 121 or instead of the engine 121. An alternator (not shown) is connected to the engine 121, and electric power is supplied from the alternator to electrical components such as the vehicle control device 11 provided in the work vehicle 10 and a battery. The battery is charged by the electric power supplied from the alternator. Electrical components such as the vehicle control device 11 and the positioning device 14 provided in the work vehicle 10 can be driven by the electric power supplied from the battery even after the engine 121 stops.

[0021] The driving force of the engine 121 is transmitted to the front wheels 122 via the transmission 124 and the front axle 125, and is transmitted to the rear wheels 123 via the transmission 124 and the rear axle 126. Further, the driving force of the engine 121 is also transmitted to the working device 13 via a PTO shaft (not shown). When the work vehicle 10 performs autonomous driving, the traveling device 12 performs a traveling operation according to an instruction from the vehicle control device 11.

[0022] The working device 13 is, for example, a tiller, a plow, a fertilizer applicator, a lawn mower, or a seeder, etc., and is detachable from the work vehicle 10. Thereby, the work vehicle 10 can perform various operations using each of the working devices 13.

[0023] Specifically, the working device 13 shown in FIG. 3 is a tiller provided with a plurality of tilling claws 132 that rotate around a rotating shaft 131 by the driving force from the engine 121 to till the field. Further, the working device 13 is supported by the work vehicle 10 so as to be liftable by a lifting mechanism (not shown). The vehicle control device 11 controls the lifting mechanism to lift and lower the working device 13. For example, when the work vehicle 10 moves forward in the work target area of the field, the vehicle control device 11 lowers the working device 13, and when the work vehicle 10 moves backward, the vehicle control device 11 raises the working device 13.

[0024] The steering wheel 127 is an operation unit operated by a user or the vehicle control device 11. For example, in the traveling device 12, according to the operation of the steering wheel 127 by the vehicle control device 11, the angle of the front wheels 122 is changed by a hydraulic power steering mechanism (not shown) or the like, and the traveling direction of the work vehicle 10 is changed.

[0025] In addition to the steering wheel 127, the traveling device 12 includes a shift lever, an accelerator, a brake, etc. (not shown) that are operated by the vehicle control device 11. In the traveling device 12, according to the operation of the shift lever by the vehicle control device 11, the gears of the transmission 124 are switched to forward gears or reverse gears, etc., and the gear ratio is operated to control the rotation speeds of the front wheels 122 and the rear wheels 123. The traveling mode of the work vehicle 10 is switched to forward or reverse, etc. Also, the vehicle control device 11 controls the rotation speed of the engine 121 by operating the accelerator. Further, the vehicle control device 11 operates the brake to brake the rotation of the front wheels 122 and the rear wheels 123 using an electromagnetic brake.

[0026] The positioning device 14 is a communication device including a control unit 141, a storage unit 142, a communication unit 143, a positioning antenna 144, etc. For example, as shown in FIG. 3, the positioning device 14 is provided above the cabin 17 where the user rides. Also, the installation location of the positioning device 14 is not limited to the cabin 17. Furthermore, the control unit 141, the storage unit 142, the communication unit 143, and the positioning antenna 144 of the positioning device 14 may be distributed and arranged at different positions in the work vehicle 10. As described above, the battery is connected to the positioning device 14, and the positioning device 14 can operate even when the engine 121 is stopped. Also, as the positioning device 14, for example, a mobile phone terminal, a smartphone, or a tablet terminal, etc. may be substituted.

[0027] The control unit 141 is a computer system including one or more processors and a storage memory such as a non-volatile memory and a RAM. The storage unit 142 is a non-volatile memory or the like that stores a positioning program for causing the control unit 141 to execute positioning processing (see FIG. 9) described later, and positioning information D1 (see FIG. 5), movement information D2 (see FIG. 6), and the like. For example, the positioning program is non-temporarily recorded on a computer-readable recording medium such as a CD or a DVD, and is read by a predetermined reading device (not shown) and stored in the storage unit 142. Note that the positioning program may be downloaded from a server (not shown) to the positioning device 14 via the communication network N1 and stored in the storage unit 142.

[0028] The communication unit 143 is a communication interface for connecting the positioning device 14 to the communication network N1 by wire or wirelessly and performing data communication according to a predetermined communication protocol with an external device such as the base station server 20 via the communication network N1.

[0029] The positioning antenna 144 is an antenna that receives radio waves (GNSS signals) transmitted from the satellite 40.

[0030] The control unit 141 includes various processing units such as a first positioning processing unit 151, a transmission processing unit 152, an acquisition processing unit 153, and a second positioning processing unit 154. Note that the control unit 141 functions as the various processing units by executing various processes according to the positioning program. Further, as another embodiment, some or all of the first positioning processing unit 151, the transmission processing unit 152, the acquisition processing unit 153, and the second positioning processing unit 154 may be configured by electronic circuits.

[0031] The first positioning processing unit 151 calculates the position of the work vehicle 10 based on the GNSS signals (an example of the satellite signals of the present invention) received by the positioning antenna 144 from the satellites 40. For example, when the work vehicle 10 autonomously travels within the farm field F, when the positioning antenna 144 receives radio waves (transmission time, orbital information, etc.) transmitted from each of the plurality of satellites 40, the first positioning processing unit 151 calculates the distance between the positioning antenna 144 and each satellite 40, and calculates the position (latitude and longitude) of the work vehicle 10 based on the calculated distances. In this way, the first positioning processing unit 151 calculates the position of the work vehicle 10 by so-called single positioning (corresponding to the first positioning of the present invention). The first positioning processing unit 151 records the positioning information (hereinafter referred to as "single positioning information") corresponding to the calculated position in the positioning information D1 of the storage unit 142. The first positioning processing unit 151 is an example of the first positioning processing unit of the present invention.

[0032] FIG. 5 is a diagram showing an example of the positioning information D1. The positioning information D1 includes single positioning information, transmission positioning information, and the like. The first positioning processing unit 151 calculates the single positioning information based on the GNSS signals received from the satellites 40. In FIG. 5, the single positioning information is indicated by X1 to X15 and Y1 to Y15, but the actual single positioning information includes latitude and longitude indicating the position of the work vehicle 10 instead of X1 to X15 and Y1 to Y15. Although the positioning information D1 shown in FIG. 5 shows time information, the time information may not be included in the positioning information D1.

[0033] The transmission processing unit 152 transmits the positioning information (single positioning information) corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151 to the base station server 20.

[0034] Specifically, the transmission processing unit 152 transmits the independent positioning information to the base station server 20 at a predetermined cycle (for example, a cycle of 1 second) in a predetermined transmission data format. For example, the transmission processing unit 152 transmits a GGA message (sentence) including the time, latitude, and longitude corresponding to the independent positioning information to the base station server 20 at a cycle of 1 second according to the data transmission standard of NMEA0183. The GGA message is an example of the positioning information (the independent positioning information) of the present invention. The transmission processing unit 152 is an example of the transmission processing unit of the present invention.

[0035] Also, the transmission processing unit 152 records the independent positioning information to be transmitted to the base station server 20 as transmission positioning information in positioning information D1 (see FIG. 5). In FIG. 5, the transmission positioning information is indicated by X1 to X12 and Y1 to Y12, but the actual transmission positioning information includes the latitude and longitude indicating the position of the work vehicle 10 instead of X1 to X12 and Y1 to Y12. In addition, in the positioning information D1, the independent positioning information and the transmission positioning information are recorded in association with each other.

[0036] When the base station server 20 receives the transmission positioning information (the independent positioning information) transmitted from the transmission processing unit 152, it selects one base station 30 from among the plurality of base stations 30 based on the position of the work vehicle 10, and generates the correction information based on the GNSS signal received by the selected base station 30 from the satellite 40. The correction information includes positioning information of the position calculated by the base station 30 based on the GNSS signal, reference position information of the position where the base station 30 is installed, time information, and the like. The base station server 20 transmits the generated correction information to the work vehicle 10. The specific configuration of the base station server 20 will be described later.

[0037] The acquisition processing unit 153 acquires the correction information from the base station server 20. The acquisition processing unit 153 acquires the correction information from the base station server 20 in real time, for example, while the work vehicle 10 is autonomously traveling. The acquisition processing unit 153 records the acquired correction information in the movement information D2. The acquisition processing unit 153 is an example of the acquisition processing unit of the present invention.

[0038] FIG. 6 is a diagram showing an example of the movement information D2. The movement information D2 includes single positioning information, correction information, position information, and the like. When the acquisition processing unit 153 acquires the correction information from the base station server 20, it records the correction information in the movement information D2 in association with the single positioning information. In FIG. 6, the correction information is indicated by Xs3 to Xs15 and Ys3 to Ys15. However, the actual correction information includes latitude and longitude indicating the position of the base station 30 (such as positioning information and reference position information), time information, etc., instead of Xs3 to Xs15 and Ys3 to Ys15. Although the movement information D2 shown in FIG. 6 shows time information, the time information may not be included in the movement information D2.

[0039] The second positioning processing unit 154 executes RTK positioning (corresponding to the specific positioning and the second positioning of the present invention) for calculating the position of the work vehicle 10 based on the correction information acquired by the acquisition processing unit 153. For example, the second positioning processing unit 154 corrects the single positioning information of the work vehicle 10 based on the signal received from the satellite 40 based on the correction information corresponding to the positioning information of the selected base station 30, and calculates the current position of the work vehicle 10. The second positioning processing unit 154 records the position information indicating the calculated current position of the work vehicle 10 in the movement information D2 (see FIG. 6). The current position of the work vehicle 10 is calculated as described above. The vehicle control device 11 executes autonomous driving processing of the work vehicle 10 based on the current position and a previously generated travel route while the positioning device 14 calculates the current position of the work vehicle 10. The second positioning processing unit 154 is an example of the second positioning processing unit of the present invention.

[0040] [Base station server 20] As shown in FIG. 2, the base station server 20 is a server including a control unit 21, a storage unit 22, a communication unit 23, and the like. Note that the base station server 20 is not limited to a single computer, and may be a computer system in which a plurality of computers cooperate to operate. Also, various processes executed by the base station server 20 may be distributed and executed by one or a plurality of processors.

[0041] The communication unit 23 is a communication interface for connecting the base station server 20 to the communication network N1, either wired or wirelessly, and performing data communication according to a predetermined communication protocol with external devices such as one or more work vehicles 10 via the communication network N1.

[0042] The storage unit 22 is a non-volatile storage unit such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) that stores various types of information. A control program for causing the control unit 21 to execute various processes is stored in the storage unit 22. For example, the control program is non-temporarily recorded on a computer-readable recording medium such as a CD or a DVD, and is read by a reading device (not shown) such as a CD drive or a DVD drive provided in the base station server 20 and stored in the storage unit 22. Note that the control program may be downloaded from a server (not shown) to the base station server 20 via the communication network N1 and stored in the storage unit 22.

[0043] In addition, the storage unit 22 contains data such as base station information D3. FIG. 7 is a diagram showing an example of the base station information D3. The base station information D3 includes a base station name, reference position information, and the like. The base station name is the name (identification information) of each of all the base stations 30 included in the positioning system 1. The reference position information is position information (latitude and longitude) indicating the installation position of the base station 30. The base station 30 is installed by a communication carrier, a local government, or the like, and the base station name and the reference position information are registered in the base station information D3 when the base station 30 is installed.

[0044] The control unit 21 includes various processing units such as a reception processing unit 211, a selection processing unit 212, a generation processing unit 213, and a transmission processing unit 214. Note that the control unit 21 functions as the various processing units by executing various processes according to the control program. Further, as another embodiment, some or all of the reception processing unit 211, the selection processing unit 212, the generation processing unit 213, and the transmission processing unit 214 may be configured by an electronic circuit.

[0045] The reception processing unit 211 receives positioning information (independent positioning information) corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151 of the positioning device 14 mounted on the work vehicle 10 from the positioning device 14. Specifically, the reception processing unit 211 receives the independent positioning information (see FIG. 5) transmitted by the transmission processing unit 152 of the positioning device 14 at a predetermined cycle (for example, a cycle of 1 second).

[0046] The selection processing unit 212 selects one base station 30 from among a plurality of base stations 30 based on the position of the work vehicle 10. Specifically, the selection processing unit 212 selects, from among the plurality of base stations 30 included in the pre-registered base station information D3, the one base station 30 that is closest to the position of the work vehicle 10 corresponding to the independent positioning information received by the reception processing unit 211.

[0047] FIG. 8 illustrates a farm field F and a work vehicle 10 that performs work within the farm field F. The farm field F is located between two base stations 30A and 30B. When the work vehicle 10 is located at the starting point P1 of the work, the reception processing unit 211 receives the independent positioning information corresponding to the point P1 from the positioning device 14. In this case, the selection processing unit 212 selects, from among the plurality of base stations 30 included in the base station information D3, the base station 30 (here, the base station 30A) that is closest to the point P1.

[0048] The generation processing unit 213 generates the correction information for correcting the position (independent positioning information) of the work vehicle 10 calculated by the first positioning processing unit 151 of the positioning device 14. Specifically, the generation processing unit 213 generates the correction information based on the GNSS signal (satellite signal) received by the base station 30 selected by the selection processing unit 212 from the satellite 40. In the example shown in FIG. 8, the generation processing unit 213 generates the correction information for the work vehicle 10 based on the GNSS signal received by the base station 30A from the satellite 40. The correction information includes positioning information of the position calculated by the base station 30A based on the GNSS signal, reference position information of the position where the base station 30A is installed (see "Xa, Ya" in FIG. 7), and time information.

[0049] The transmission processing unit 214 transmits the correction information generated by the generation processing unit 213 to the work vehicle 10. When the work vehicle 10 acquires the correction information first transmitted from the base station server 20, the positioning by the RTK method (RTK positioning) is started. That is, when the work vehicle 10 acquires the correction information corresponding to the selected base station 30 first transmitted from the base station server 20, the RTK positioning based on the correction information corresponding to the base station 30 becomes possible. In the present embodiment, the state where "RTK positioning based on the correction information corresponding to the selected one base station 30 (base station 30A in the above example) is possible" is also referred to as "the state where the communication between the work vehicle 10 and the base station 30 (base station 30A) is established".

[0050] As described above, the positioning system 1 positions the work vehicle 10 by the RTK method. Further, the work vehicle 10 performs autonomous driving using the positioning information by the RTK method.

[0051] Incidentally, for example, when the farm field F is located at the midpoint between two base stations 30, the base station 30 may switch while the work vehicle 10 is autonomously traveling within the farm field F. For example, as shown in FIG. 8, when the intermediate point C0 between the base station 30A and the base station 30B is located within the farm field F, the farm field F includes a first region F1 on the base station 30A side of the intermediate point C0 and a second region F2 on the base station 30B side of the intermediate point C0. In this case, the work vehicle 10 autonomously travels while acquiring the position information calculated using the correction information corresponding to the base station 30A within the first region F1. However, when the work vehicle 10 crosses the intermediate point C0 and enters the second region F2, the base station 30B becomes the base station closest to the work vehicle 10, so the base station 30 that establishes communication with the work vehicle 10 switches. As a result, the correction information in the work vehicle 10 switches and the positioning calculation by the RTK method temporarily stops, and the autonomous driving of the work vehicle 10 is interrupted. In the example shown in FIG. 8, it is possible to perform RTK positioning of the work vehicle 10 using the correction information corresponding to the base station 30A when the work vehicle 10 is located in the first region F1 and when it is located in the second region F2. Also, it is possible to perform RTK positioning of the work vehicle 10 using the correction information corresponding to the base station 30B. That is, in the farm field F, RTK positioning using the respective correction information corresponding to a plurality of base stations 30 is possible.

[0052] On the other hand, as described below, according to the positioning device 14 according to the present embodiment, when positioning the work vehicle 10 based on the correction information corresponding to a specific base station 30, it is possible to prevent the switching of the base station 30.

[0053] Here, an example shown in FIG. 8 will be described. When the work vehicle 10 is located at the point P1 in the first area F1, the base station server 20 selects the base station 30A (the base station closest to the point P1) based on the individual positioning information corresponding to the point P1 received from the work vehicle 10, generates correction information corresponding to the selected base station 30A, and transmits it to the work vehicle 10. When the acquisition processing unit 153 of the positioning device 14 acquires the first correction information from the base station server 20, RTK positioning corresponding to the base station 30A becomes possible. That is, communication between the work vehicle 10 and the base station 30A is established.

[0054] When RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A (corresponding to the second positioning of the present invention) becomes possible, the transmission processing unit 152 of the positioning device 14 transmits the same positioning information as the individual positioning information immediately before RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible to the base station server 20. The individual positioning information includes at least latitude information, longitude information, and time information. For example, when RTK positioning of the work vehicle 10 becomes possible, the transmission processing unit 152 transmits the same latitude information and longitude information as the longitude information and the latitude information immediately before RTK positioning of the work vehicle 10 becomes possible to the base station server 20.

[0055] For example, assume that the positioning device 14 transmits the single positioning information "X3, Y3" (see FIG. 5) to the base station server 20, the base station server 20 selects the base station 30A based on the single positioning information "X3, Y3", and the selected base station 30A generates correction information based on the GNSS signal received from the satellite 40 and transmits the first correction information to the work vehicle 10. The positioning device 14 can perform RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A by acquiring the first correction information from the base station server 20. In this case, as shown in FIG. 5, the transmission processing unit 152 of the positioning device 14 transmits the same positioning information "X3, Y3" as the single positioning information "X3, Y3" transmitted immediately before the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible to the base station server 20. That is, the transmitted positioning information transmitted from the positioning device 14 to the base station server 20 is fixed to the single positioning information "X3, Y3" immediately before the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible (see FIG. 5).

[0056] As a result, while the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A is possible, the transmission processing unit 152 continues to transmit the same independent positioning information "X3, Y3" to the base station server 20 regardless of the position of the work vehicle 10. For example, in the example shown in FIG. 8, when the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A is possible at all positions within the farm field F, even when the work vehicle 10 moves from the first area F1 to the point P2 in the second area F2, the transmission processing unit 152 continues to transmit the independent positioning information "X3, Y3" corresponding to the position within the first area F1 to the base station server 20. For this reason, since the base station server 20 receives the same independent positioning information "X3, Y3" (transmitted positioning information) regardless of the actual position of the work vehicle 10, it continues to select the base station 30A and does not select the base station 30B. Then, the base station server 20 continues to transmit the correction information corresponding to the base station 30A to the work vehicle 10. As a result, the positioning device 14 continues to receive the correction information corresponding to the base station 30A without interruption while the work vehicle 10 is at least traveling within the farm field F, and continues to calculate the current position of the work vehicle 10. Therefore, it is possible to prevent the autonomous driving of the work vehicle 10 from being interrupted within the farm field F.

[0057] In this way, when RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible, the acquisition processing unit 153 of the positioning device 14 acquires, from the base station server 20, the correction information generated based on the GNSS signal received by the base station 30A from the satellite 40, and the second positioning processing unit 154 positions the work vehicle 10 based on the correction information corresponding to the base station 30A acquired by the acquisition processing unit 153. Specifically, when RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible, in each case where the work vehicle 10 is located at a location closer to the base station 30A than the base station 30B (the first region F1 in FIG. 8) and at a location closer to the base station 30B than the base station 30A (the second region F2 in FIG. 8), the acquisition processing unit 153 acquires the correction information corresponding to the base station 30A from the base station server 20, and the second positioning processing unit 154 calculates the position of the work vehicle 10 based on the correction information corresponding to the base station 30A acquired by the acquisition processing unit 153. In other words, when RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible, in each case where the work vehicle 10 travels in the first region F1 and travels in the second region F2, the second positioning processing unit 154 positions the position of the work vehicle 10 based on the correction information corresponding to the base station 30A.

[0058] Also, when RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible, even when the work vehicle 10 moves from a location close to the base station 30A (the first region F1 in FIG. 8) to a location close to the base station 30B (the second region F2 in FIG. 8), the acquisition processing unit 153 acquires the correction information corresponding to the base station 30A from the base station server 20, and the second positioning processing unit 154 positions the position of the work vehicle 10 based on the correction information corresponding to the base station 30A acquired by the acquisition processing unit 153. In this way, the positioning device 14 calculates the current position of the work vehicle 10.

[0059] [Positioning Processing] Next, with reference to FIG. 9, an example of the positioning process executed by the control unit 141 of the positioning device 14 will be described. For example, the positioning process is started by the control unit 141 when the control unit 141 receives a satellite signal (GNSS signal) from the satellite 40. Further, the positioning process may be started in response to a predetermined user operation on the work vehicle 10 equipped with the positioning device 14.

[0060] Note that the invention of the present application may be regarded as an invention of a positioning method for executing part or all of the positioning process by the control unit 141, or an invention of a positioning program for causing the control unit 141 to execute part or all of the positioning method. Further, the positioning process may be executed by one or a plurality of processors. For example, the positioning process may be executed in cooperation by the control unit 141 of the positioning device 14 and the control unit 21 of the base station server 20.

[0061] In step S1, the control unit 141 starts a reception process of receiving a GNSS signal from the satellite 40. For example, the control unit 141 receives radio waves (GNSS signals) including transmission times, orbital information, etc. from each of a plurality (4) of satellites 40.

[0062] In step S2, the control unit 141 (first positioning processing unit 151) starts independent positioning for calculating the position of the work vehicle 10 based on the GNSS signal received from the satellite 40. The control unit 141 records positioning information (independent positioning information) corresponding to the calculated position in the positioning information D1 (see FIG. 5) of the storage unit 142.

[0063] In step S3, the control unit 141 (transmission processing unit 152) starts a transmission process of transmitting the independent positioning information corresponding to the position of the work vehicle 10 calculated in step S2 to the base station server 20. For example, the control unit 141 transmits a GGA message including the time, latitude, and longitude corresponding to the independent positioning information to the base station server 20 at a cycle of 1 second according to the data transmission standard of NMEA0183. Further, the control unit 141 records the independent positioning information to be transmitted to the base station server 20 in the positioning information D1 (see FIG. 5) as transmitted positioning information.

[0064] The base station server 20 selects the base station 30 closest to the work vehicle 10 based on the individual positioning information transmitted from the positioning device 14, generates correction information corresponding to the selected base station 30, and transmits it to the work vehicle 10.

[0065] In step S4, the control unit 141 determines whether RTK positioning has become possible. For example, when the control unit 141 acquires the first correction information from the base station server 20, it determines that RTK positioning has become possible (S4: Yes), and the process proceeds to step S5. The control unit 141 waits until it acquires the first correction information from the base station server 20 (S4: No). For example, in the example shown in FIG. 8, when the control unit 141 acquires the first correction information corresponding to the base station 30A from the base station server 20, it determines that RTK positioning based on the correction information corresponding to the base station 30A has become possible.

[0066] In step S5, the control unit 141 (transmission processing unit 152) fixes the individual positioning information (transmission positioning information) to be transmitted to the base station server 20 to the individual positioning information immediately before RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible (refer to "X3, Y3" in FIG. 5). That is, in the above example, the control unit 141 transmits the individual positioning information "X3, Y3" (GGA message) to the base station server 20 at a cycle of 1 second. Also, the control unit 141 transmits only the latitude information and longitude information ("X3, Y3") of the individual positioning information to the base station server 20 at a cycle of 1 second. Note that the time information included in the GGA message is updated.

[0067] In step S6, the control unit 141 (acquisition processing unit 153) determines whether it has acquired the correction information from the base station server 20. Here, the control unit 141 determines whether it has acquired the correction information corresponding to the base station 30A. When the control unit 141 acquires the correction information (S6: Yes), the process proceeds to step S7. The control unit 141 waits until it acquires the correction information (S6: No).

[0068] After the individual positioning information is fixed, the control unit 141 continues to transmit the same individual positioning information ("X3, Y3") to the base station server 20. Further, the base station server 20 selects the base station 30A based on the individual positioning information ("X3, Y3") transmitted from the positioning device 14, and continues to generate correction information corresponding to the selected base station 30A and transmit it to the work vehicle 10. Thereby, the control unit 141 continues to acquire the correction information corresponding to the same base station 30A regardless of the position of the work vehicle 10.

[0069] In step S7, the control unit 141 (the second positioning processing unit 154) corrects the position corresponding to the individual positioning information of the work vehicle 10 calculated in step S2 based on the correction information acquired in step S6, and calculates the current position of the work vehicle 10. Here, the control unit 141 corrects the position corresponding to the individual positioning information based on the correction information corresponding to the base station 30A, and calculates the current position of the work vehicle 10. Further, as shown in FIG. 8, even when the work vehicle 10 is located in the first region F1 or in the second region F2, the control unit 141 calculates the current position of the work vehicle 10 using the correction information corresponding to the base station 30A.

[0070] In step S8, the control unit 141 determines whether the work by the work vehicle 10 has ended. For example, when the work vehicle 10 has completed the work in all regions within the farm field F, that is, when the autonomous driving on the set travel route has been completed, the control unit 141 determines that the work by the work vehicle 10 has ended (S8: Yes). When the work ends, the control unit 141 ends the positioning process. On the other hand, when the control unit 141 determines that the work by the work vehicle 10 has not ended (S8: No), the process proceeds to step S6. When the process proceeds to step S6, the control unit 141 continues the process of acquiring the correction information from the base station server 20 and calculating the current position of the work vehicle 10. As described above, the control unit 141 executes the positioning process.

[0071] Incidentally, when the distance L10 between the positioning device 14 and the base station 30 becomes equal to or greater than a predetermined distance, the communication environment with the base station 30 deteriorates, and it becomes impossible to perform positioning (RTK positioning) of the moving object to be positioned (the work vehicle 10 in this embodiment). For example, when the work vehicle 10 (positioning device 14) is more than 5 km away from the base station 30A, the positioning device 14 cannot perform RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A.

[0072] Here, in the example shown in FIG. 8, for example, when the distance L10 between the work vehicle 10 and the base station 30A is less than the predetermined distance regardless of the position of the work vehicle 10 in the field F, the positioning device 14 can perform RTK positioning based on the correction information corresponding to the base station 30A. However, for example, as shown in FIG. 10, when the work vehicle 10 moves to a point P4 outside the field F or the like and the distance L10 between the work vehicle 10 and the base station 30A becomes equal to or greater than the predetermined distance, a problem occurs in that the positioning device 14 cannot perform RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A. Note that the predetermined distance at which the positioning device 14 can perform RTK positioning based on the correction information corresponding to the base station 30A varies depending on the communication environment between the positioning device 14 and the base station 30. Therefore, for example, when the work vehicle 10 moves too far away from the base station 30A while the positioning device 14 is in a state where it can perform RTK positioning based on the correction information corresponding to the base station 30A, the positioning device 14 becomes unable to perform the RTK positioning at that time.

[0073] Therefore, when it becomes impossible to perform RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A, the transmission processing unit 152 releases the fixation of the single positioning information and transmits the single positioning information corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151 to the base station server 20 after it becomes impossible to perform RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A.

[0074] For example, in FIG. 5, time t9 represents the time when the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes impossible due to the movement of the work vehicle 10. When the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes impossible, the transmission processing unit 152 releases the fixation of the single positioning information "X3, Y3", and transmits the single positioning information "X9, Y9" corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151 after the release to the base station server 20. Thereafter, the transmission processing unit 152 sequentially transmits new single positioning information calculated by the first positioning processing unit 151 according to the position of the work vehicle 10 to the base station server 20.

[0075] Also, when the fixation of the single positioning information "X3, Y3" is released, for example, when the work vehicle 10 moves beyond the intermediate point C0 toward the base station 30B side, the base station server 20 selects the base station 30B in order to acquire the single positioning information on the base station 30B side. Then, the base station server 20 generates correction information based on the GNSS signal received by the base station 30B from the satellite 40 and transmits it to the positioning device 14. In the positioning device 14, the acquisition processing unit 153 acquires the correction information corresponding to the base station 30B from the base station server 20, and the second positioning processing unit 154 positions the position corresponding to the single positioning information of the work vehicle 10 calculated by the first positioning processing unit 151 based on the correction information corresponding to the base station 30B acquired by the acquisition processing unit 153, and calculates the current position of the work vehicle 10.

[0076] The configuration of switching the base station 30 for establishing communication with the work vehicle 10 as described above and calculating the current position of the work vehicle 10 is effective, for example, when the work vehicle 10 moves to the field Fb after finishing the work in the field Fa and performs work in the field Fb as shown in FIG. 11. In the example shown in FIG. 11, the work vehicle 10 starts working at the point P5 in the field Fb. Note that at the point P5, the distance L10 between the work vehicle 10 and the base station 30B is less than a predetermined distance.

[0077] When the work vehicle 10 is located at the point P5 where the work starts, the transmission processing unit 152 transmits the independent positioning information "X12, Y12" (see Fig. 5) corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151 to the base station server 20. The reception processing unit 211 of the base station server 20 receives the independent positioning information "X12, Y12" corresponding to the point P5 from the positioning device 14. In this case, the selection processing unit 212 selects the base station 30B closest to the point P5 from among the plurality of base stations 30 included in the base station information D3. The generation processing unit 213 generates the correction information for the work vehicle 10 based on the GNSS signal received by the base station 30B from the satellite 40, and the transmission processing unit 214 transmits the generated correction information corresponding to the base station 30B to the work vehicle 10. When the work vehicle 10 acquires the correction information corresponding to the selected base station 30B transmitted from the base station server 20 for the first time, RTK positioning based on the correction information corresponding to the base station 30B becomes possible.

[0078] Also, as shown in Fig. 5, the transmission processing unit 152 of the positioning device 14 transmits the same positioning information "X12, Y12" as the independent positioning information "X12, Y12" transmitted immediately before the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B becomes possible to the base station server 20. That is, the transmitted positioning information transmitted from the positioning device 14 to the base station server 20 is fixed to the independent positioning information "X12, Y12" immediately before the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B becomes possible (see Fig. 5).

[0079] As a result, while the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B is possible, the transmission processing unit 152 continues to transmit the same single positioning information "X12, Y12" to the base station server 20 regardless of the position of the work vehicle 10. And when the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B is possible at all positions within the farm field Fb, the transmission processing unit 152 continues to transmit the same single positioning information "X12, Y12" to the base station server 20. For this reason, since the base station server 20 receives the same single positioning information "X12, Y12" (transmitted positioning information) regardless of the actual position of the work vehicle 10, it continues to select the base station 30B and does not select other base stations 30. And the base station server 20 continues to transmit the correction information corresponding to the base station 30B to the work vehicle 10. As a result, while the work vehicle 10 is traveling at least within the farm field Fb, the positioning device 14 continues to receive the correction information corresponding to the base station 30B without interruption and continues to calculate the current position of the work vehicle 10. Therefore, it is possible to prevent the autonomous driving of the work vehicle 10 from being interrupted within the farm field Fb.

[0080] An example of the positioning process corresponding to the examples shown in FIGS. 10 and 11 will be described with reference to FIG. 12. In the positioning process shown in FIG. 12, the same step numbers are assigned to the same processes as those shown in FIG. 9 and the description thereof is omitted. In the positioning process shown in FIG. 12, the processes of steps S81 and S82 are further added to the positioning process shown in FIG. 9.

[0081] In step S8, when the control unit 141 determines that the work by the work vehicle 10 has not ended (S8: No), the process proceeds to step S81.

[0082] In step S81, the control unit 141 determines whether it has become impossible to perform RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A with which the work vehicle 10 has established communication. If the control unit 141 determines that RTK positioning corresponding to the base station 30A has become impossible (S81: Yes), the process proceeds to step S82. On the other hand, if the control unit 141 determines that RTK positioning corresponding to the base station 30A is possible (S81: No), the process proceeds to step S6.

[0083] In step S82, the control unit 141 releases the fixation of the independent positioning information. For example, as shown in FIG. 10, when the work vehicle 10 moves from point P3 to point P4 and the work vehicle 10 cannot obtain the correction information from the base station 30A and RTK positioning becomes impossible, the control unit 141 releases the fixation of the independent positioning information "X3, Y3" (see FIG. 5). After the control unit 141 releases the fixation of the independent positioning information "X3, Y3", then in step S3, it starts transmitting independent positioning information corresponding to the position of the work vehicle 10.

[0084] Thereafter, in step S4, the control unit 141 determines whether RTK positioning of the work vehicle 10 has become possible. Here, for example, in the examples shown in FIGS. 10 and 11, when the control unit 141 acquires the first correction information corresponding to the base station 30B from the base station server 20, it determines that RTK positioning based on the correction information corresponding to the base station 30B has become possible (S4: Yes).

[0085] Also, in step S5, the control unit 141 fixes the independent positioning information (transmitted positioning information) to be transmitted to the base station server 20 to the independent positioning information immediately before RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B becomes possible (see "X12, Y12" in FIG. 5). Then, the control unit 141 acquires the correction information corresponding to the base station 30B (step S6), and corrects the position corresponding to the independent positioning information of the work vehicle 10 calculated in step S2 based on the correction information acquired in step S6 to calculate the current position of the work vehicle 10 (step S7).

[0086] As described above, the positioning device 14 calculates (single positioning) the position (single positioning information) of the moving body (work vehicle 10) based on the satellite signals (GNSS signals) received from the satellites 40, and transmits the calculated single positioning information to the base station server 20. The base station server 20 selects one base station 30 from among a plurality of base stations 30 based on the single positioning information, generates correction information corresponding to the selected base station 30, and transmits the correction information to the positioning device 14. When the positioning device 14 acquires the correction information from the base station server 20, the positioning device 14 positions the work vehicle 10 based on the correction information. Further, when RTK positioning of the moving body based on the correction information corresponding to the selected base station 30 becomes possible, the positioning device 14 transmits the same positioning information as the single positioning information transmitted immediately before the RTK positioning of the moving body based on the correction information becomes possible to the base station server 20. In this way, the positioning device 14 fixes the position information of the single positioning information so that the base station 30 cannot be switched in the base station server 20. Thereby, for example, when the farm field F is located at an intermediate point between two base stations (see FIG. 8), it is possible to prevent the base station 30 corresponding to the correction information from being switched while the work vehicle 10 is autonomously traveling within the farm field F. For this reason, for example, it is possible to prevent the reception of the correction information from being interrupted from the base station server 20 and the autonomous driving of the work vehicle 10 from being interrupted.

[0087] [Other Embodiments] Hereinafter, other embodiments of the positioning system 1 according to the present embodiment will be described.

[0088] As another embodiment, the positioning device 14 may preset a range in which RTK positioning is possible (hereinafter referred to as "positioning possible range AR"). For example, the positioning device 14 sets a range with a radius R (for example, 5 km) centered on the work vehicle 10 (positioning device 14) as the positioning possible range AR.

[0089] Here, in the example shown in FIG. 13, for example, when the base station 30A is included in the positioning range AR regardless of the position of the work vehicle 10 in the field F, RTK positioning is possible. However, for example, when the work vehicle 10 is located at a point P4 outside the field F, the base station 30A is out of the positioning range AR. In FIG. 13, “AR4” indicates the positioning range AR corresponding to the point P4, and “AR3” indicates the positioning range AR corresponding to the point P3. In this case, the positioning device 14 cannot perform RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A.

[0090] The control unit 141 determines whether the base station 30A is within the positioning range AR based on the positioning information of the base station 30A included in the correction information. When the base station 30A is out of the positioning range AR, it is determined that RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes impossible. That is, when the base station 30A is located within a predetermined range (positioning range AR) from the work vehicle 10, RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible, and when the base station 30A is located outside the predetermined range from the work vehicle 10, RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes impossible.

[0091] When RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes impossible, the transmission processing unit 152 releases the fixation of the single positioning information and transmits the single positioning information corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151 after RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes impossible to the base station server 20.

[0092] After that, for example, when the work vehicle 10 moves beyond the intermediate point C0 toward the base station 30B, the base station server 20 selects the base station 30B in order to acquire the individual positioning information on the base station 30B side. Then, the base station server 20 generates correction information based on the GNSS signal received by the base station 30B from the satellite 40 and transmits the correction information to the positioning device 14. In the positioning device 14, the acquisition processing unit 153 acquires the correction information corresponding to the base station 30B from the base station server 20, and the second positioning processing unit 154 positions the position corresponding to the individual positioning information of the work vehicle 10 calculated by the first positioning processing unit 151 based on the correction information corresponding to the base station 30B acquired by the acquisition processing unit 153, and calculates the current position of the work vehicle 10.

[0093] Here, as shown in FIG. 14, when a farm field Fb exists on the base station 30B side and the work vehicle 10 moves to the farm field Fb after finishing the work in the farm field Fa and performs work in the farm field Fb, the positioning device 14 executes the same processing as in the above-described embodiment to calculate the current position of the work vehicle 10.

[0094] Further, as another embodiment, the positioning device 14 may be configured to measure the distance between the work vehicle 10 and the base station 30 and switch the base station 30 that is the target of RTK positioning to the base station 30 closer to the work vehicle 10. For example, as shown in FIG. 11, when the work vehicle 10 is located within the farm field Fb, the positioning device 14 switches the base station 30 that is the target of RTK positioning from the base station 30A to the base station 30B when the work vehicle 10 moves beyond the intermediate point C0 toward the base station 30B side.

[0095] Specifically, when the base station 30 closest to the work vehicle 10 changes from the base station 30A to the base station 30B, the transmission processing unit 152 releases the fixation of the individual positioning information and transmits the individual positioning information corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151 to the base station server 20. Thereby, the base station server 20 selects the base station 30B in order to acquire the individual positioning information on the base station 30B side. Then, the base station server 20 generates correction information based on the GNSS signal received from the satellite 40 by the base station 30B and transmits it to the positioning device 14. In the positioning device 14, the acquisition processing unit 153 acquires the correction information corresponding to the base station 30B from the base station server 20, and the second positioning processing unit 154 positions the position corresponding to the individual positioning information of the work vehicle 10 calculated by the first positioning processing unit 151 based on the correction information corresponding to the base station 30B acquired by the acquisition processing unit 153, and calculates the current position of the work vehicle 10.

[0096] In this way, the positioning device 14 may monitor the distance between the work vehicle 10 and the base station 30 and automatically switch the base station 30 that is the target of RTK positioning to the base station 30 closest to the work vehicle 10.

[0097] For example, as shown in FIG. 15, there may be a case where the farm field F located between the two base stations 30A and 30B is located on the side of one of the base stations (here, the base station 30B side). That is, the farm field F includes two divided areas divided at the midpoint between the base station 30A and the base station 30B, and the area of one divided area is larger than that of the other divided area. Here, the farm field F is divided into a first area F1 on the base station 30A side and a second area F2 on the base station 30B side, and the area of the second area F2 is larger than that of the first area F1. When positioning the work vehicle 10 traveling in such a farm field F, from the viewpoint of positioning accuracy, it is desirable to position the work vehicle 10 using the correction information corresponding to the base station 30B on the side of the second area F2 with a larger area.

[0098] However, for example, when the base station server 20 selects the base station 30A at the timing when the work vehicle 10 is located at the point P1 and generates correction information corresponding to the base station 30A and transmits it to the positioning device 14, the positioning device 14 calculates the current position of the work vehicle 10 using the correction information corresponding to the base station 30A regardless of the position of the work vehicle 10 within the farm field F. Therefore, for example, when the work vehicle 10 is located in the second region F2, the distance between the work vehicle 10 and the base station 30A becomes long, so there is a risk that the positioning accuracy of the work vehicle 10 may decrease.

[0099] Therefore, as another embodiment, the transmission processing unit 152 transmits the independent positioning information corresponding to the second region F2 (an example of the first divided region of the present invention) with a large area to the base station server 20. Further, the acquisition processing unit 153 acquires correction information generated based on the GNSS signal received by the base station 30B close to the second region F2 with a large area from the satellite 40. Then, the second positioning processing unit 154 calculates (positions) the position of the work vehicle 10 based on the correction information acquired by the acquisition processing unit 153.

[0100] Specifically, when the work vehicle 10 is first located in the first region F1 with a small area, the positioning device 14 calculates the current position of the work vehicle 10 based on the independent positioning information. That is, when the work start point of the work vehicle 10 is the first region F1, while traveling in the first region F1, the work vehicle 10 performs autonomous driving using the position information calculated based on the independent positioning information calculated by the first positioning processing unit 151. Therefore, the transmission processing unit 152 does not transmit the independent positioning information to the base station server 20 while the work vehicle 10 is traveling in the first region F1.

[0101] After that, when the work vehicle 10 enters the large-area second region F2, the transmission processing unit 152 transmits the independent positioning information within the second region F2 calculated by the first positioning processing unit 151 to the base station server 20. As a result, the base station server 20 selects the base station 30B, generates correction information corresponding to the base station 30B, and transmits it to the positioning device 14. When the positioning device 14 acquires the correction information from the base station server 20 and RTK positioning of the work vehicle 10 based on the correction information becomes possible, the transmission processing unit 152 transmits the same positioning information as the independent positioning information transmitted immediately before the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B becomes possible to the base station server 20. That is, the transmitted positioning information transmitted from the positioning device 14 to the base station server 20 is fixed to the independent positioning information immediately before the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B becomes possible.

[0102] Then, when RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B becomes possible, in each case where the work vehicle 10 travels in the first region F1 and the second region F2, the second positioning processing unit 154 calculates the position of the work vehicle 10 based on the correction information corresponding to the base station 30B.

[0103] As a result, after the independent positioning information is fixed, the positioning device 14 can calculate the current position of the work vehicle 10 using the correction information corresponding to the base station 30B regardless of the position of the work vehicle 10 (first region F1, second region F2) within the farm field F. In this way, the positioning device 14 calculates the current position of the work vehicle 10 by independent positioning in the narrow-area first region F1, and then, when it moves to the large-area second region F2, thereafter, it calculates the current position of the work vehicle 10 by RTK positioning using the correction information corresponding to the base station 30B close to the second region F2.

[0104] Note that when the work vehicle 10 is initially located in the large-area second region F2, according to the configuration shown in the above embodiment, it is possible to calculate the current position of the work vehicle 10 using the correction information corresponding to the base station 30B throughout the farm field F.

[0105] In each of the above-described embodiments, a work vehicle has been taken as an example of the moving body (mobile station) of the present invention. However, the moving body of the present invention is not limited to a work vehicle. For example, the moving body of the present invention may be an operator who moves while possessing the positioning device 14. Further, the positioning device of the present invention may be a device pre-mounted on a vehicle, or may be a portable device that can be brought into (detachable from) the vehicle. Further, in each of the above-described embodiments, a case where the work vehicle 10 performs autonomous driving based on the position information calculated by the positioning device 14 has been taken as an example. However, the usage form of the position information calculated by the positioning device 14 is not limited to the autonomous driving of the work vehicle 10. For example, the position information calculated by the positioning device 14 may be used for the creation process of the travel route of the work vehicle 10, the creation process of the travel locus traveled by the work vehicle 10 during work, and the like.

[0106] A positioning device according to an aspect of the present invention includes a first positioning processing unit, a transmission processing unit, an acquisition processing unit, and a second positioning processing unit. The first positioning processing unit executes a first positioning for calculating the position of a moving body based on satellite signals received from satellites. The transmission processing unit transmits positioning information corresponding to the position of the moving body calculated by the first positioning processing unit to a base station server that selects one base station based on the position of the moving body calculated by the first positioning processing unit from a plurality of base stations. The acquisition processing unit acquires correction information generated based on satellite signals received by the one base station from the satellites from the base station server. The second positioning processing unit executes a second positioning for calculating the position of the moving body based on the correction information acquired by the acquisition processing unit. Further, when the second positioning of the moving body based on the first correction information corresponding to the first base station, which is the one base station, becomes possible, the transmission processing unit transmits the same positioning information as the positioning information immediately before the second positioning of the moving body based on the first correction information becomes possible to the base station server.

[0107] A work vehicle according to an aspect of the present invention includes the positioning device and a control device that executes a travel process based on the position information calculated by the positioning device.

[0108] A positioning method according to an aspect of the present invention includes executing a first positioning for calculating the position of a moving object based on satellite signals received from satellites, and transmitting positioning information corresponding to the calculated position of the moving object to a base station server that selects one base station from a plurality of base stations based on the calculated position of the moving object, obtaining correction information generated based on the satellite signals received by the one base station from the satellites from the base station server, and executing a second positioning for calculating the position of the moving object based on the correction information, which is executed by one or more processors. Further, in the positioning method, when the second positioning of the moving object based on the first correction information corresponding to the first base station, which is the one base station, becomes possible, the same positioning information as the positioning information immediately before the second positioning of the moving object based on the first correction information becomes possible is transmitted to the base station server.

[0109] A positioning program according to an aspect of the present invention causes one or more processors to execute a first positioning for calculating the position of a moving object based on satellite signals received from satellites, transmitting positioning information corresponding to the calculated position of the moving object to a base station server that selects one base station from a plurality of base stations based on the calculated position of the moving object, obtaining correction information generated based on the satellite signals received by the one base station from the satellites from the base station server, and executing a second positioning for calculating the position of the moving object based on the correction information. Further, in the positioning program, when the second positioning of the moving object based on the first correction information corresponding to the first base station, which is the one base station, becomes possible, the same positioning information as the positioning information immediately before the second positioning of the moving object based on the first correction information becomes possible is transmitted to the base station server.

[0110] The positioning method according to the present invention is such that when one or more processors can perform specific positioning to calculate the position of a moving object based on correction information generated based on satellite signals received by a base station in a field, by using the positioning information of the position of the moving object in the field calculated based on the satellite signals immediately before the specific positioning becomes possible, the specific positioning is performed based on the correction information corresponding to the same base station at all positions in the field.

[0111] The work vehicle according to the present invention is such that the moving object is a work vehicle that travels in the field, and includes a positioning device that positions the work vehicle by the positioning method, and a control device that executes travel processing based on the position information calculated by the positioning device.

[0112] The positioning device according to the present invention is such that when specific positioning to calculate the position of a moving object based on correction information generated based on satellite signals received by a base station in a field becomes possible, by using the positioning information of the position of the moving object in the field calculated based on the satellite signals immediately before the specific positioning becomes possible, the specific positioning is performed based on the correction information corresponding to the same base station at all positions in the field.

[0113] The positioning program according to the present invention is a positioning program for causing one or more processors to perform the specific positioning based on the correction information corresponding to the same base station at all positions in the field by using the positioning information of the position of the moving object in the field calculated based on the satellite signals immediately before the specific positioning becomes possible when the specific positioning to calculate the position of the moving object based on the correction information generated based on the satellite signals received by a base station in a field becomes possible.

Explanation of Signs

[0114] 1: Positioning system 10: Work vehicle 14: Positioning device 20: Base station server 30: Base station 40: Satellite 144: Positioning antenna 151: First positioning processing unit 152: Transmission processing unit 153: Acquisition processing unit 154: Second positioning processing unit 211: Reception processing unit 212: Selection processing unit 213: Generation processing unit 214: Transmission processing unit

Claims

1. While one or more processors are capable of performing specific positioning to calculate the position of a mobile object based on first correction information generated based on satellite signals received by one base station from a satellite, other base stations do not perform the specific positioning based on second correction information generated based on satellite signals received by the other base stations from the satellite. Positioning method.

2. The one or more processors When the specific positioning becomes possible, while the specific positioning is possible, obtain the first correction information from a base station server that selects one base station based on positioning information of the position of the mobile object from among a plurality of base stations, and perform the specific positioning based on the obtained first correction information. The positioning method according to Claim 1.

3. The positioning information includes at least longitude information, latitude information, and time information. When the specific positioning of the mobile object becomes possible, the one or more processors transmit the longitude information and the latitude information immediately before the specific positioning of the mobile object becomes possible to the base station server. The positioning method according to Claim 2.

4. The mobile object is a work vehicle that travels in a farm field, A positioning device that positions the work vehicle by the positioning method according to any one of Claims 1 to 3, A control device that executes a travel process based on position information calculated by the positioning device, A work vehicle comprising the same.

5. While one or more processors are capable of performing specific positioning to calculate the position of a mobile object based on first correction information generated based on satellite signals received by one base station from a satellite, other base stations do not perform the specific positioning based on second correction information generated based on satellite signals received by the other base stations from the satellite. Positioning system.

Images