Patent Application
20230280474
The present invention relates to a positioning device or the like that calculates a current position of a moving object.
There has been conventionally known a real-time kinematic system (RTK-GPS positioning system; hereinafter, referred to as “RTK system”) capable of measuring a position of a work vehicle such as a tractor with high accuracy. The RTK system can perform highly accurate positioning by using correction information corresponding to a base station (reference station) near the work vehicle.
A virtual reference station (VRS) system is also known as another positioning system. For example, Patent Document 1 discloses a technique in which a VRS information broadcasting center generates VRS reference information of antenna stations (Ak: A1 to An) by using satellite observation information from fixed reference stations (R1 to R4) and transmits the generated VRS reference information to a mobile station.
However, the conventional technique selects a base station closest to a work vehicle and calculates a current position of the work vehicle by using correction information corresponding to the base station, and thus, for example, in a case where a field where the work vehicle works exists at an intermediate point between two base stations, the base station corresponding to the correction information may be switched while the work vehicle is autonomously traveling in the field. When the base station is switched while the work vehicle is autonomously traveling, positioning by the RTK system is temporarily stopped to interrupt the autonomous traveling of the work vehicle, which is problematic. This problem is not limited to a work vehicle that autonomously travels in the field and may similarly occur in various systems that measure a position of a moving object by using correction information.
An object of the present invention is to provide a positioning device, a work vehicle, a positioning method, and a positioning program capable of preventing a base station from being switched in a case where a position of a moving object is measured on the basis of correction information corresponding to a specific base station.
A positioning device according to 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 performs first positioning for calculating a position of a moving object on the basis of a satellite signal received from a satellite. The transmission processing unit transmits positioning information corresponding to the position of the moving object calculated by the first positioning processing unit to a base station server that selects one base station from among a plurality of base stations on the basis of the position of the moving object calculated by the first positioning processing unit. The acquisition processing unit acquires, from the base station server, correction information generated based on a satellite signal received by the one base station from the satellite. The second positioning processing unit performs second positioning for calculating the position of the moving object on the basis of the correction information acquired by the acquisition processing unit. Further, when the second positioning of the moving object based on first correction information corresponding to a first base station that is the one base station becomes possible, the transmission processing unit transmits, to the base station server, the same positioning information as the positioning information obtained immediately before the second positioning of the moving object based on the first correction information becomes possible.
A work vehicle according to the present invention includes the positioning device and a control device that performs traveling processing on the basis of position information calculated by the positioning device.
A positioning method according to the present invention is a positioning method in which one or a plurality of processors executes: performing first positioning for calculating a position of a moving object on the basis of a satellite signal received from a satellite; transmitting positioning information corresponding to the calculated position of the moving object to a base station server that selects one base station from among a plurality of base stations on the basis of the calculated position of the moving object; acquiring, from the base station server, correction information generated based on a satellite signal received by the one base station from the satellite; and performing second positioning for calculating the position of the moving object on the basis of the correction information. Further, in the positioning method, when the second positioning of the moving object based on first correction information corresponding to a first base station that is the one base station becomes possible, the same positioning information as the positioning information obtained immediately before the second positioning of the moving object based on the first correction information becomes possible is transmitted to the base station server.
A positioning program according to the present invention is a positioning program for causing one or a plurality of processors to execute: performing first positioning for calculating a position of a moving object on the basis of a satellite signal received from a satellite; transmitting positioning information corresponding to the calculated position of the moving object to a base station server that selects one base station from among a plurality of base stations on the basis of the calculated position of the moving object; acquiring, from the base station server, correction information generated based on a satellite signal received by the one base station from the satellite; and performing second positioning for calculating the position of the moving object on the basis of the correction information. Further, in the positioning program, when the second positioning of the moving object based on first correction information corresponding to a first base station that is the one base station becomes possible, the same positioning information as the positioning information obtained immediately before the second positioning of the moving object based on the first correction information becomes possible is transmitted to the base station server.
According to the present invention, it is possible to provide a positioning device, a work vehicle, a positioning method, and a positioning program capable of preventing a base station from being switched in a case where a position of a moving object is measured on the basis of correction information corresponding to a specific base station.
The following embodiments are examples of embodying the present invention and do not limit the technical scope of the present invention.
As illustrated in
In the present embodiment, an example where the work vehicle 10 is a tractor will be described. As another embodiment, the work vehicle 10 may be a rice transplanter, a combine harvester, a construction machinery, a snowplow, or the like. The work vehicle 10 can autonomously travel (automatically travel) along a traveling route in a field F (see
The satellite 40 is a positioning satellite included in a satellite positioning system such as a global navigation satellite system (GNSS) and transmits a GNSS signal (satellite signal). The positioning system 1 includes a plurality of satellites 40. The base station 30 is a reference point (reference station) included in the satellite positioning system and is installed at a plurality of points in advance. In the present embodiment, there are two base stations 30A and 30B as an example. The base station server 20 is a management server that manages the 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 a first base station of the present invention, and the base station 30B is an example of a second base station of the present invention.
The work vehicle 10 performs positioning processing of calculating the current position (latitude and longitude) of the work vehicle 10 on the basis of the GNSS signal transmitted from the satellite 40 and the correction information transmitted from the base station server 20. In the present embodiment, the positioning system 1 measures the position of the work vehicle 10 by using a positioning method by the RTK system. The positioning method by the RTK system is well known, and thus detailed description thereof will be omitted, and only an overview thereof will be described below. For example, when receiving a GNSS signal from the satellite 40, the work vehicle 10 calculates the position of the work vehicle 10 (point positioning) on the basis of the GNSS signal. The base station server 20 generates correction information for correcting the position on the basis of positioning information (e.g., GNSS signal) acquired from the base station 30 closest to the work vehicle 10. The positioning system 1 corrects the calculated position of the work vehicle 10 on the basis of the correction information, thereby calculating the current position of the work vehicle 10. The work vehicle 10 autonomously travels along the traveling route while acquiring the current position in the field F.
[Work Vehicle 10]
As illustrated in
The vehicle control device 11 is a computer system including one or a plurality of processors and storage memories such as a non-volatile memory and a RAM. The vehicle control device 11 controls operation of the work vehicle 10 in response to various user operations on the work vehicle 10. The vehicle control device 11 performs autonomous traveling processing of the work vehicle 10 on the basis of the current position of the work vehicle 10 calculated by the positioning device 14 described later and the traveling route (see
The travel device 12 is a drive unit that causes the work vehicle 10 to travel. As illustrated in
The engine 121 is a drive source such as a diesel engine or gasoline engine driven by using fuel supplied to a fuel tank (not illustrated). The travel device 12 may include an electric motor as a drive source together with the engine 121 or instead of the engine 121. The engine 121 is connected to a generator (not illustrated), and the generator supplies power to electric components such as the vehicle control device 11 provided in the work vehicle 10, a battery, and the like. The battery is charged with power supplied from the generator. The electric components such as the vehicle control device 11 and the positioning device 14 provided in the work vehicle 10 can be driven by power supplied from the battery even after the engine 121 is stopped.
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. The driving force of the engine 121 is also transmitted to the work device 13 via a PTO shaft (not illustrated). In a case where the work vehicle 10 autonomously travels, the travel device 12 performs a traveling operation in accordance with a command from the vehicle control device 11.
The work device 13 is, for example, a tiller, a plow, a fertilizer machine, a mower, or a seeder machine and is detachable from the work vehicle 10. Therefore, the work vehicle 10 can perform various works by using the respective work devices 13.
Specifically, the work device 13 in
The steering wheel 127 is an operation unit operated by a user or the vehicle control device 11. For example, in the travel device 12, an angle of the front wheels 122 is changed by a hydraulic power steering mechanism (not illustrated) or the like in response to an operation on the steering wheel 127 by the vehicle control device 11, thereby changing a traveling direction of the work vehicle 10.
The travel device 12 includes not only the steering wheel 127 but also, for example, a shift lever, an accelerator, and a brake (not illustrated) operated by the vehicle control device 11. In the travel device 12, in response to an operation on the shift lever by the vehicle control device 11, a gear of the transmission 124 is switched to a forward gear, a back gear, or the like, and a speed ratio is operated, thereby controlling a rotational speed of the front wheels 122 and the rear wheels 123. A traveling mode of the work vehicle 10 is switched to, for example, forward movement or backward movement. The vehicle control device 11 operates the accelerator to control a rotational speed of the engine 121. The vehicle control device 11 operates the brake to slow down the rotation of the front wheels 122 and the rear wheels 123 by using an electromagnetic brake.
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, and the like. For example, as illustrated in
The control unit 141 is a computer system including one or a plurality of processors and storage memories such as a non-volatile memory and a RAM. The storage unit 142 is, for example, a non-volatile memory that stores a positioning program for causing the control unit 141 to perform positioning processing (see
The communication unit 143 is a communication interface for connecting the positioning device 14 to the communication network N1 in a wired or wireless manner 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.
The positioning antenna 144 receives a radio wave (GNSS signal) transmitted from the satellite 40.
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. The control unit 141 functions as the various processing units by performing various kinds of processing according to the positioning program. 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 an electronic circuit.
The first positioning processing unit 151 calculates the position of the work vehicle 10 on the basis of a GNSS signal (an example of a satellite signal of the present invention) received by the positioning antenna 144 from the satellite 40. For example, in a case where the work vehicle 10 autonomously travels in the field F and the positioning antenna 144 receives a radio wave (transmission time, orbit information, and the like) transmitted from each of the plurality of satellites 40, the first positioning processing unit 151 calculates a distance between the positioning antenna 144 and each satellite 40 and calculates the position (latitude and longitude) of the work vehicle 10 on the basis of the calculated distance. In this manner, the first positioning processing unit 151 calculates the position of the work vehicle 10 by so-called point positioning (corresponding to first positioning of the present invention). The first positioning processing unit 151 records positioning information corresponding to the calculated position (hereinafter, referred to as “point positioning information”) in the positioning information D1 of the storage unit 142. The first positioning processing unit 151 is an example of a first positioning processing unit of the present invention.
The transmission processing unit 152 transmits the positioning information (point 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.
Specifically, the transmission processing unit 152 transmits the point positioning information to the base station server 20 on a predetermined cycle (e.g., one-second cycle) 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 point positioning information to the base station server 20 on a one-second cycle according to the data transmission standard of the NMEA 0183. The GGA message is an example of positioning information (the point positioning information) of the present invention. The transmission processing unit 152 is an example of a transmission processing unit of the present invention.
The transmission processing unit 152 records the point positioning information to be transmitted to the base station server 20 in the positioning information D1 (see
When receiving the transmission positioning information (the point positioning information) transmitted from the transmission processing unit 152, the base station server 20 selects one base station 30 from among the plurality of base stations 30 on the basis of the position of the work vehicle 10 and generates the correction information on the basis of a 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 on the basis of the GNSS signal, reference position information of a position in which 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. A specific configuration of the base station server 20 will be described later.
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 while, for example, 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 an acquisition processing unit of the present invention.
The second positioning processing unit 154 performs RTK positioning (corresponding to second positioning of the present invention) for calculating the position of the work vehicle 10 on the basis of the correction information acquired by the acquisition processing unit 153. For example, the second positioning processing unit 154 corrects the point positioning information of the work vehicle 10 based on the signal received from the satellite 40 on the basis of the correction information corresponding to the positioning information of the selected base station 30, thereby calculating 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
[Base Station Server 20]
As illustrated in
The communication unit 23 is a communication interface for connecting the base station server 20 to the communication network N1 in a wired or wireless manner and performing data communication according to a predetermined communication protocol with an external device such as one or a plurality of work vehicles 10 via the communication network N1.
The storage unit 22 is a non-volatile storage unit such as a hard disk drive (HDD) or a solid state drive (SSD) that stores various kinds of information. The storage unit 22 stores a control program for causing the control unit 21 to perform various kinds of processing. For example, the control program is non-temporarily recorded in a computer-readable recording medium such as a CD or DVD, is read by a reading device (not illustrated) such as a CD drive or DVD drive included in the base station server 20, and is stored in the storage unit 22. The control program may be downloaded from a server (not illustrated) to the base station server 20 via the communication network N1 and be stored in the storage unit 22.
The storage unit 22 includes data such as base station information D3.
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. The control unit 21 functions as the various processing units by performing various kinds of processing according to the control program. 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.
The reception processing unit 211 receives, from the positioning device 14, positioning information (point 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. Specifically, the reception processing unit 211 receives the point positioning information (see
The selection processing unit 212 selects one base station 30 from among the plurality of base stations 30 on the basis of the position of the work vehicle 10. Specifically, the selection processing unit 212 selects one base station 30 closest to the position of the work vehicle 10 corresponding to the point positioning information received by the reception processing unit 211 from among the plurality of base stations 30 included in the base station information D3 registered in advance.
The generation processing unit 213 generates the correction information for correcting the position (point 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 on the basis of a GNSS signal (satellite signal) received from the satellite 40 by the base station 30 selected by the selection processing unit 212. In the example of
The transmission processing unit 214 transmits the correction information generated by the generation processing unit 213 to the work vehicle 10. In a case where the work vehicle 10 acquires the correction information transmitted first from the base station server 20, positioning by the RTK system (RTK positioning) is started. That is, when the work vehicle 10 acquires the correction information corresponding to the selected base station 30 transmitted first 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, a “state in which RTK positioning based on correction information corresponding to one selected base station 30 (the base station 30A in the above example) can be performed” is also referred to as a “state in which communication between the work vehicle 10 and the base station 30 (base station 30A) is established”.
As described above, the positioning system 1 measures the position of the work vehicle 10 by the RTK system. The work vehicle 10 performs autonomous traveling by using positioning information by the RTK system.
By the way, for example, in a case where the field F is located at an intermediate point between the two base stations 30, the base station 30 may be switched while the work vehicle 10 is autonomously traveling in the field F. For example, as illustrated in
Meanwhile, as described below, in a case where the position of the work vehicle 10 is measured based on correction information corresponding to a specific base station 30, the positioning device 14 according to the present embodiment can prevent the base station 30 from being switched.
Here, the example of
When the 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, to the base station server 20, the same positioning information as the point positioning information obtained immediately before the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible. The point positioning information includes at least latitude information, longitude information, and time information. For example, when the RTK positioning of the work vehicle 10 becomes possible, the transmission processing unit 152 transmits, to the base station server 20, the same latitude information and longitude information as the longitude information and the latitude information obtained immediately before the RTK positioning of the work vehicle 10 becomes possible.
For example, the positioning device 14 is assumed to transmit point positioning information “X3, Y3” (see
Therefore, regardless of the position of the work vehicle 10, the transmission processing unit 152 continues to transmit the same point positioning information “X3, Y3” to the base station server 20 while the RTK positioning of the work vehicle 10 can be performed based on the correction information corresponding to the base station 30A. For example, in the example of
As described above, when the 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 a GNSS signal received by the base station 30A from the satellite 40, and the second positioning processing unit 154 measures the position of the work vehicle 10 on the basis of the correction information corresponding to the base station 30A acquired by the acquisition processing unit 153. Specifically, when the 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 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 on the basis of the correction information corresponding to the base station 30A acquired by the acquisition processing unit 153 in each case where: the work vehicle 10 is located in a place (the first region F1 in
When the 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 acquires the correction information corresponding to the base station 30A from the base station server 20, and the second positioning processing unit 154 measures the position of the work vehicle 10 on the basis of the correction information corresponding to the base station 30A acquired by the acquisition processing unit 153 even in a case where the work vehicle 10 moves from the place (the first region F1 in
[Positioning Processing]
Hereinafter, an example of the positioning processing performed by the control unit 141 of the positioning device 14 will be described with reference to
The invention of the present application may be regarded as an invention of a positioning method for performing a part or all of the positioning processing by the control unit 141 or an invention of a positioning program for causing the control unit 141 to perform a part or all of the positioning method. The positioning processing may be performed by one or a plurality of processors. For example, the positioning processing may be cooperatively performed by the control unit 141 of the positioning device 14 and the control unit 21 of the base station server 20.
In step S1, the control unit 141 starts reception processing of receiving a GNSS signal from the satellite 40. For example, the control unit 141 receives a radio wave (GNSS signal) including transmission time, orbit information, and the like from each of the plurality of (four) satellites 40.
In step S2, the control unit 141 (first positioning processing unit 151) starts point positioning for calculating the position of the work vehicle 10 on the basis of the GNSS signal received from the satellite 40. The control unit 141 records positioning information (point positioning information) corresponding to the calculated position in the positioning information D1 (see
In step S3, the control unit 141 (transmission processing unit 152) starts transmission processing of transmitting the point 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 point positioning information to the base station server 20 on a one-second cycle according to the data transmission standard of the NMEA 0183. The control unit 141 records the point positioning information to be transmitted to the base station server 20 in the positioning information D1 (see
The base station server 20 selects the base station 30 closest to the work vehicle 10 on the basis of the point positioning information transmitted from the positioning device 14, generates correction information corresponding to the selected base station 30, and transmits the correction information to the work vehicle 10.
In step S4, the control unit 141 determines whether or not RTK positioning has become possible. For example, when acquiring the first correction information from the base station server 20 (S4: Yes), the control unit 141 determines that the RTK positioning has become possible, and the processing proceeds to step S5. The control unit 141 waits until acquiring the first correction information from the base station server 20 (S4: No). For example, in the example of
In step S5, the control unit 141 (transmission processing unit 152) fixes the point positioning information (transmission positioning information) to be transmitted to the base station server 20 to the point positioning information (see “X3, Y3” in
In step S6, the control unit 141 (acquisition processing unit 153) determines whether or not the correction information has been acquired from the base station server 20. Here, the control unit 141 determines whether or not the correction information corresponding to the base station 30A has been acquired. When the control unit 141 acquires the correction information (S6: Yes), the processing proceeds to step S7. The control unit 141 waits until acquiring the first correction information from the base station server 20 (S6: No).
After the point positioning information is fixed, the control unit 141 continues to transmit the same point positioning information (“X3, Y3”) to the base station server 20. The base station server 20 continues to select the base station 30A on the basis of the point positioning information (“X3, Y3”) transmitted from the positioning device 14, generate correction information corresponding to the selected base station 30A, and transmit the correction information to the work vehicle 10. Therefore, 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.
In step S7, the control unit 141 (second positioning processing unit 154) corrects the position corresponding to the point positioning information of the work vehicle 10 calculated in step S2 on the basis of the correction information acquired in step S6 and calculates a current position of the work vehicle 10. Here, the control unit 141 corrects the position corresponding to the point positioning information on the basis of the correction information corresponding to the base station 30A and calculates the current position of the work vehicle 10. As illustrated in
In step S8, the control unit 141 determines whether or not work by the work vehicle 10 has been finished. For example, when the work vehicle 10 completes the work in the whole region of the field F, that is, when the work vehicle completes autonomous traveling along the set traveling route, the control unit 141 determines that the work by the work vehicle 10 has been finished (S8: Yes). When the work is completed, the control unit 141 ends the positioning processing. Meanwhile, when the control unit 141 determines that the work by the work vehicle 10 has not been finished (S8: No), the processing proceeds to step S6. When the processing proceeds to step S6, the control unit 141 continues the processing 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 performs the positioning processing.
By the way, when a distance L10 between the work vehicle 10 and the base station 30 is equal to or more than a predetermined distance, a communication environment with the base station 30 deteriorates, and the positioning device 14 cannot perform positioning (RTK positioning) on a moving object of which the position is to be measured (the work vehicle 10 in the present embodiment). For example, when the work vehicle 10 (positioning device 14) is away from the base station 30A by 5 km or more, the positioning device 14 cannot perform RTK positioning on the work vehicle 10 on the basis of the correction information corresponding to the base station 30A.
Here, in the example of
Therefore, 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 point positioning information and transmits, to the base station server 20, point positioning information corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151 after the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes impossible.
For example, in
When the fixation of the point positioning information “X3, Y3” is released, for example, when the work vehicle 10 moves to the base station 30B side beyond the intermediate point CO, the base station server 20 selects the base station 30B in order to acquire the point positioning information on the base station 30B side. Then, the base station server 20 generates correction information on the basis of a 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 measures the position corresponding to the point positioning information of the work vehicle 10 calculated by the first positioning processing unit 151 on the basis of 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.
The above configuration in which the base station 30 that establishes communication with the work vehicle 10 is switched to calculate the current position of the work vehicle 10 is effective in a case where, for example, the work vehicle 10 finishes work in a field Fa, then moves to a field Fb, and works in the field Fb as illustrated in
In a case where the work vehicle 10 is located at the point P5 where the work vehicle starts work, the transmission processing unit 152 transmits point positioning information “X12, Y12” (see
As illustrated in
Therefore, regardless of the position of the work vehicle 10, the transmission processing unit 152 continues to transmit the same point positioning information “X12, Y12” to the base station server 20 while the RTK positioning of the work vehicle 10 can be performed based on the correction information corresponding to the base station 30B. In a case where the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B can be performed at all positions in the field Fb, the transmission processing unit 152 continues to transmit the same point positioning information “X12, Y12” to the base station server 20. Therefore, the base station server 20 continues to select the base station 30B and does not select another base station 30 because the base station server receives the same point positioning information “X12, Y12” (transmission positioning information), regardless of the actual position of the work vehicle 10. Then, the base station server 20 continues to transmit the correction information corresponding to the base station 30B to the work vehicle 10. Therefore, 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 while the work vehicle 10 is traveling at least in the field Fb. This makes it possible to prevent the autonomous traveling of the work vehicle 10 from being interrupted in the field Fb.
An example of the positioning processing corresponding to the examples of
In step S8, when the control unit 141 determines that work by the work vehicle 10 has not been finished (S8: No), the processing proceeds to step S81.
In step S81, the control unit 141 determines whether or not the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A that has established communication with the work vehicle 10 has become impossible. When the control unit 141 determines that the RTK positioning corresponding to the base station 30A has become impossible (S81: Yes), the processing proceeds to step S82. Meanwhile, when the control unit 141 determines that the RTK positioning corresponding to the base station 30A is possible (S81: No), the processing proceeds to step S6.
In step S82, the control unit 141 releases the fixation of the point positioning information. For example, as illustrated in
Thereafter, in step S4, the control unit 141 determines whether or not the RTK positioning of the work vehicle 10 has become possible. Here, for example, in the examples of
In step S5, the control unit 141 fixes the point positioning information (transmission positioning information) to be transmitted to the base station server 20 to the point positioning information (see “X12, Y12” in
As described above, the positioning device 14 calculates (point positioning) the position (point positioning information) of the moving object (work vehicle 10) on the basis of a satellite signal (GNSS signal) received from the satellite 40 and transmits the calculated point positioning information to the base station server 20. The base station server 20 selects one base station 30 from among the plurality of base stations 30 on the basis of the point positioning information, generates correction information corresponding to the selected base station 30, and transmits the correction information to the positioning device 14. When acquiring the correction information from the base station server 20, the positioning device 14 measures the position of the work vehicle 10 on the basis of the correction information. In a case where RTK positioning of the moving object based on the correction information corresponding to the selected base station 30 becomes possible, the positioning device 14 transmits, to the base station server 20, the same positioning information as the point positioning information transmitted immediately before the RTK positioning of the moving object based on the correction information becomes possible. In this manner, the positioning device 14 fixes the position information of the point positioning information so that the base station 30 is not switched in the base station server 20. Therefore, for example, in a case where the field F is located at an intermediate point between two base stations (see
Hereinafter, other embodiments of the positioning system 1 according to the present embodiment will be described.
As another embodiment, the positioning device 14 may set in advance a range in which RTK positioning can be performed (hereinafter, referred to as a “positionable range AR”). For example, the positioning device 14 sets a range having a radius R (e.g., 5 km) around the work vehicle 10 (positioning device 14) as the positionable range AR.
In an example of
The control unit 141 determines whether or not the base station 30A falls within the positionable range AR on the basis of the positioning information of the base station 30A included in the correction information, and, in a case where the base station 30A does not fall within the positionable range AR, the control unit determines that the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A has become impossible. That is, when the base station 30A is located within a predetermined range (positionable range AR) from the work vehicle 10, the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes possible. Meanwhile, when the base station 30A is located outside the predetermined range from the work vehicle 10, the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes impossible.
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 fixation of the point positioning information and transmits, to the base station server 20, point positioning information corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151 after the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30A becomes impossible.
Thereafter, for example, when the work vehicle 10 moves to the base station 30B side beyond the intermediate point CO, the base station server 20 selects the base station 30B in order to acquire the point positioning information on the base station 30B side. Then, the base station server 20 generates correction information on the basis of a 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 measures the position corresponding to the point positioning information of the work vehicle 10 calculated by the first positioning processing unit 151 on the basis of 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.
Here, as illustrated in
As still another embodiment, the positioning device 14 may measure the distance between the work vehicle 10 and the base station 30 and switch the base station 30 to be subjected to the RTK positioning to the base station 30 closer to the work vehicle 10. For example, as illustrated in
Specifically, in a case where 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 point positioning information and transmits, to the base station server 20, point positioning information corresponding to the position of the work vehicle 10 calculated by the first positioning processing unit 151. Therefore, the base station server 20 selects the base station 30B in order to acquire the point positioning information on the base station 30B side. Then, the base station server 20 generates correction information on the basis of a 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 measures the position corresponding to the point positioning information of the work vehicle 10 calculated by the first positioning processing unit 151 on the basis of 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.
As described above, the positioning device 14 may monitor the distance between the work vehicle 10 and the base station 30 and switch the base station 30 to be subjected to the RTK positioning to the base station 30 closest to the work vehicle 10 by itself.
For example, as illustrated in
However, for example, in a case where the base station server 20 selects the base station 30A at a timing when the work vehicle 10 is located at the point P1, generates correction information corresponding to the base station 30A, and transmits the correction information to the positioning device 14, the positioning device 14 calculates the current position of the work vehicle 10 by using the correction information corresponding to the base station 30A, regardless of the position of the work vehicle 10 in the field F. Therefore, for example, in a case where the work vehicle 10 is located in the second region F2, the distance between the work vehicle 10 and the base station 30A increases, which may reduce the positioning accuracy of the work vehicle 10.
In view of this, as still another embodiment, the transmission processing unit 152 transmits point positioning information corresponding to the second region F2 having a larger area (an example of the first divided region of the present invention) to the base station server 20. The acquisition processing unit 153 acquires correction information generated based on a GNSS signal received from the satellite 40 by the base station 30B closer to the second region F2 having a larger area. Then, the second positioning processing unit 154 calculates (measures) the position of the work vehicle 10 on the basis of the correction information acquired by the acquisition processing unit 153.
Specifically, in a case where the work vehicle 10 is initially located in the first region F1 having a smaller area, the positioning device 14 calculates the current position of the work vehicle 10 on the basis of the point positioning information. That is, in a case where a work start point is in the first region F1, the work vehicle 10 autonomously travels by using position information calculated based on the point positioning information calculated by the first positioning processing unit 151 while traveling in the first region F1. Therefore, the transmission processing unit 152 does not transmit the point positioning information to the base station server 20 while the work vehicle 10 is traveling in the first region F1.
Thereafter, when the work vehicle 10 enters the second region F2 having a larger area, the transmission processing unit 152 transmits the point positioning information in the second region F2 calculated by the first positioning processing unit 151 to the base station server 20. Therefore, the base station server 20 selects the base station 30B, generates correction information corresponding to the base station 30B, 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 and the RTK positioning of the work vehicle 10 based on the correction information becomes possible, the transmission processing unit 152 transmits, to the base station server 20, the same positioning information as the point 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. That is, the transmission positioning information transmitted from the positioning device 14 to the base station server 20 is fixed to the point positioning information obtained immediately before the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B becomes possible.
Then, when the RTK positioning of the work vehicle 10 based on the correction information corresponding to the base station 30B becomes possible, the second positioning processing unit 154 calculates the position of the work vehicle 10 on the basis of the correction information corresponding to the base station 30B in each case where: the work vehicle 10 travels in the first region F1; and the work vehicle 10 travels in the second region F2.
Therefore, after the point positioning information is fixed, the positioning device 14 can calculate the current position of the work vehicle 10 by using the correction information corresponding to the base station 30B, regardless of the position (the first region F1 or the second region F2) of the work vehicle 10 in the field F. In this manner, the positioning device 14 calculates the current position of the work vehicle 10 by point positioning in the first region F1 having a smaller area, and thereafter, in a case where the work vehicle moves to the second region F2 having a larger area, then the positioning device 14 calculates the current position of the work vehicle 10 by RTK positioning using the correction information corresponding to the base station 30B closer to the second region F2.
Note that, in a case where the work vehicle 10 is initially located in the second region F2 having a larger area, it is possible to calculate the current position of the work vehicle 10 by using the correction information corresponding to the base station 30B in the entire field F by the configuration described in the above embodiment.
In each of the above embodiments, the work vehicle is taken as an example of the moving object (mobile station) of the present invention. However, the moving object of the present invention is not limited to the work vehicle. For example, the moving object of the present invention may be a worker who moves while carrying the positioning device 14. The positioning device of the present invention may be a device mounted on a vehicle in advance or may be a portable device that can be brought into (detachable from) the vehicle. In each of the above embodiments, there has been described the example where the work vehicle 10 autonomously travels based on the position information calculated by the positioning device 14. However, the use form of the position information calculated by the positioning device 14 is not limited to the autonomous traveling of the work vehicle 10. For example, the position information calculated by the positioning device 14 may be used for processing of creating a traveling route of the work vehicle 10 or processing of creating a traveling track along which the work vehicle 10 has traveled during work.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-139843 | Aug 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/027860 | 7/28/2021 | WO |
