Position acquisition device and recording medium having position acquisition program recorded thereon

Abstract

To suppress unnecessary consumption of power by performing positioning processing when a position signal from a satellite cannot be properly received.SOLUTION: The position acquisition device 1 is a position acquisition device 1 that is attached to a pallet 4 being transported and acquires position information PS indicating the position of the pallet 4 from the GNSS system 2, and is equipped with a movement determination unit 111 that determines the movement state of the pallet 4, a reception state determination unit 112 that determines the reception state of the position signal SP from the GNSS system 2, and an acquisition unit 113 that acquires the position information PS depending on the determination result of the movement determination unit 111 and the determination result of the reception state determination unit 112.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a position acquisition device and a recording medium on which a position acquisition program is recorded. [Background technology]

[0002] Patent document 1 describes that a location information acquisition terminal is attached to a pallet and equipped with an acceleration sensor, and when the acceleration sensor detects acceleration equal to or greater than a predetermined threshold, the location information acquisition terminal acquires location information. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-47932 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, positioning is performed when the movement of a pallet is detected, regardless of the environment in which the location information acquisition terminal is placed. Therefore, for example, even if the location signal from the satellite cannot be properly received, the positioning process is performed, which may result in unnecessary consumption of power. [Means for solving the problem]

[0005] One aspect of the present disclosure is a position acquisition device that is attached to an object being transported and acquires position information indicating the position of the object from a GNSS system, the position acquisition device comprising: a movement determination unit that determines the movement state of the object; a reception state determination unit that determines the reception state of a position signal from the GNSS system; and an acquisition unit that acquires the position information depending on the determination results of the movement determination unit and the reception state determination unit.

[0006] Another aspect of the present disclosure is a recording medium having a position acquisition program recorded thereon, the position acquisition device being attached to an object being transported and acquiring position information indicating the position of the object from a GNSS system, the position acquisition device having a processor, the processor functioning as a movement determination unit that determines the movement state of the object, a reception state determination unit that determines the reception state of a position signal from the GNSS system, and an acquisition unit that acquires the position information depending on the determination result of the movement determination unit and the determination result of the reception state determination unit. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a position acquisition device according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a diagram showing an example of an arrangement of position acquisition devices on a pallet. [Diagram 3] FIG. 4 is a diagram showing an example of an output of a gyro sensor. [Figure 4] FIG. 11 is a diagram showing another example of an output of a gyro sensor. [Diagram 5] 10 is a flowchart showing an example of processing of a control unit. [Figure 6] 10 is a flowchart showing an example of processing of a control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the present embodiment will be described with reference to the drawings. 1 is a diagram showing an example of the configuration of a position acquisition device 1 according to this embodiment. The position acquisition device 1 includes a control unit 11, a GNSS receiver 12, a gyro sensor 13, a communication interface 14, and a battery 15. The control unit 11 controls each part of the position acquisition device 1. The battery 15 supplies power to each part of the position acquisition device 1 according to instructions from the control unit 11.

[0009] The GNSS receiver 12 receives a GNSS signal from a Global Navigation Satellite System (GNSS) system 2 in accordance with an instruction from the control unit 11. The GNSS receiver 12 includes an antenna. The GNSS receiver 12 outputs the GNSS signal received from the GNSS system 2 to the control unit 11. The GNSS signal includes a position signal SP, an orbit signal SE, and a number signal SM. The position signal SP corresponds to position information PS indicating the position of the GNSS receiver 12. The orbit signal SE indicates satellite orbit information SF. The number signal SM indicates the number SN of satellites used to calculate the position information PS. Furthermore, the GNSS receiver 12 is turned on and off according to instructions from the control unit 11. The GNSS receiver 12 is formed, for example, from an integrated circuit (IC).

[0010] The gyro sensor 13 detects the angular velocity α of the position acquisition device 1 . The position acquisition device 1 is placed on a pallet 4 . The palette 4 and the angular velocity α will be further explained with reference to FIG.

[0011] The communication interface 14 includes a connector and an interface circuit, and is connected to the control unit 11. The communication interface 14 is an interface for communicating with the server device 3. The communication interface 14 is an interface for communicating with the server device 3 in accordance with, for example, the Wi-Fi (registered trademark) standard.

[0012] The server device 3 receives the position information PS of the pallet 4 from the position acquisition device 1. Then, the server device 3 tracks the position of the pallet 4 based on the received position information PS. The server device 3 is communicably connected to, for example, a smartphone (not shown), and transmits the position of the pallet 4 to the smartphone.

[0013] The control unit 11 includes a processor 11A and a memory 11B. The memory 11B is a storage device that non-volatilely stores programs and data executed by the processor 11A. The memory 11B is configured by a semiconductor storage element such as a magnetic storage device or a flash ROM (Read Only Memory), or other types of non-volatile storage devices. The memory 11B may also include a RAM (Random Access Memory) that configures the work area of ​​the processor 11A. The memory 11B stores data processed by the control unit 11, and the control program PG executed by the processor 11A, etc.

[0014] The processor 11A may be configured as a single processor, or may be configured such that a plurality of processors function as the processor 11A. The processor 11A controls each part of the position acquisition device 1 by executing a control program PG. The control program PG corresponds to an example of a "position acquisition program". The memory 11B corresponds to an example of a "recording medium."

[0015] The processor 11A may be configured as a SoC (System on Chip) integrated with part or all of the memory 11B and other circuits. The processor 11A may also be configured as a combination of a CPU (Central Processing Unit) that executes a program and a DSP (Digital Signal Processor) that executes a predetermined arithmetic process. All of the functions of the processor 11A may be implemented in hardware, or may be configured using a programmable device. In the following, a case where the processor 11A controls each part of the position acquisition device 1 by executing the control program PG will be described.

[0016] Next, the pallet 4 and the angular velocity α will be described with reference to Fig. 2. Fig. 2 is a diagram showing an example of the arrangement of the position acquisition device 1 on the pallet 4. The pallet 4 is made of, for example, wood or plastic. 2, the position acquisition device 1 is disposed approximately at the center in the X-axis direction and the Y-axis direction of the pallet 4. In this embodiment, a case will be described in which the upper and lower surfaces of the pallet 4 are disposed parallel to the horizontal direction.

[0017] The X-axis, Y-axis, and Z-axis are perpendicular to each other. The X-axis and Y-axis are parallel to the horizontal direction. The Z-axis is parallel to the vertical direction. The X-axis is parallel to the front-to-back direction of the pallet 4. The Y-axis is parallel to the left-to-right direction of the pallet 4. The positive direction of the X-axis indicates the front direction of the pallet 4. The positive direction of the Y-axis indicates the right direction of the pallet 4. The positive direction of the Z-axis indicates the upward direction of the pallet 4. The pallet 4 corresponds to an example of an "object to be transported."

[0018] Cargo is placed on the top surface of the pallet 4. The pallet 4 is transported by a first transport device TE1 and a second transport device TE2. The first transport device TE1 includes a forklift FL. The second transport device TE2 is a transport device different from the first transport device TE1 and includes a truck TR. The first conveyance device TE1 is a conveyance device that allows the GNSS receiver 12 to receive a GNSS signal of appropriate strength from the GNSS system 2 when the pallet 4 is being conveyed by the first conveyance device TE1. The second conveyance device TE2 is a conveyance device in which the GNSS receiver 12 cannot receive a GNSS signal of appropriate strength from the GNSS system 2 when the pallet 4 is being conveyed by the second conveyance device TE2.

[0019] In this embodiment, a case will be described in which the first transfer device TE1 is a forklift FL and the second transfer device TE2 is a truck TR. For example, the forklift FL carries the pallet 4 loaded on the truck TR into the warehouse. Also, the forklift FL carries the pallet 4 placed in the warehouse out and loads it onto the truck TR. In this way, since the forklift FL moves outdoors or near the entrance / exit of the warehouse, the position acquisition device 1 of the pallet 4 being transported by the forklift FL can receive GNSS signals of appropriate strength from the GNSS system 2. The truck TR transports multiple pallets 4, for example, from a source to a warehouse, from a warehouse to another warehouse, or from a warehouse to a destination. A metal cargo storage is placed on the loading platform of the truck TR, and multiple pallets 4 are placed in the cargo storage. Therefore, the position acquisition device 1 of the pallet 4 being transported by the truck TR cannot receive a GNSS signal of appropriate strength from the GNSS system 2. The forklift FL corresponds to an example of a "first conveying device." The truck TR corresponds to an example of a "second transport device."

[0020] In addition, when the pallet 4 is transported by a forklift FL, the front direction of the pallet 4 coincides with the front direction of the forklift FL, the right direction of the pallet 4 coincides with the right direction of the forklift FL, and the upward direction of the pallet 4 coincides with the upward direction of the forklift FL. Furthermore, when the pallet 4 is transported by the truck TR, the front direction of the pallet 4 coincides with the front direction of the truck TR, the right direction of the pallet 4 coincides with the right direction of the truck TR, and the upward direction of the pallet 4 coincides with the upward direction of the truck TR.

[0021] The angular velocity α is composed of the X-axis angular velocity αX, the Y-axis angular velocity αY, and the Z-axis angular velocity αZ. The angular velocity α indicates the rotation angle per unit time.

[0022] The gyro sensor 13 of the position acquisition device 1 detects the X-axis angular velocity αX, the Y-axis angular velocity αY, and the Z-axis angular velocity αZ as the angular velocity α. The gyro sensor 13 also outputs the detected X-axis angular velocity αX, the Y-axis angular velocity αY, and the Z-axis angular velocity αZ to the control unit 11.

[0023] The X-axis angular velocity αX indicates a clockwise angular velocity α with respect to the positive direction of the X-axis. For example, when the inclination of the pallet 4 in the left-right direction changes, the X-axis angular velocity αX is generated. The Y-axis angular velocity αY indicates a clockwise angular velocity α with respect to the positive direction of the Y-axis. For example, when the inclination of the pallet 4 in the front-to-rear direction changes, the Y-axis angular velocity αY is generated. The Z-axis angular velocity αZ indicates a clockwise angular velocity α with respect to the positive direction of the Z-axis. For example, when the pallet 4 rotates around the Z-axis, the Z-axis angular velocity αZ is generated.

[0024] Next, returning to Fig. 1, a functional configuration of the control unit 11 will be described with reference to Fig. 1. The control unit 11 includes a movement determination unit 111, a reception state determination unit 112, an acquisition unit 113, a first communication control unit 114, a second communication control unit 115, a trajectory information storage unit 116, and a position information storage unit 117. Specifically, the processor 11A executes the control program PG to function as a movement determination unit 111, a reception state determination unit 112, an acquisition unit 113, a first communication control unit 114, and a second communication control unit 115. In addition, the processor 11A executes the control program PG to cause the memory 11B to function as a trajectory information storage unit 116 and a position information storage unit 117.

[0025] The orbit information storage unit 116 stores orbit information SF of the satellite. The orbit information SF corresponds to the orbit signal SE. The orbit signal SE is included in the GNSS signal that the GNSS receiver 12 receives from the GNSS system 2. The orbit information SF corresponds to so-called ephemeris. The orbit information SF corresponds to the orbit signal SE acquired from the GNSS receiver 12 by the acquisition unit 113. The orbit information SF is stored in the orbit information storage unit 116 by the acquisition unit 113. The orbit information SF stored in the orbit information storage unit 116 is updated by the acquisition unit 113. The trajectory information storage unit 116 corresponds to an example of a "storage unit."

[0026] The position information storage unit 117 stores position information PS indicating the position of the GNSS receiver 12. The position information PS corresponds to a position signal SP acquired from the GNSS receiver 12 by the acquisition unit 113. In addition, the position information PS is stored in the position information storage unit 117 by the acquisition unit 113.

[0027] The movement determination unit 111 determines the movement state of the pallet 4. For example, the movement determination unit 111 determines the movement state of the pallet 4 according to the output of the gyro sensor 13. Furthermore, the movement determination unit 111 determines whether the pallet 4 is being moved by a forklift FL or a truck TR according to the output of the gyro sensor 13. The processing of the movement determination unit 111 will be further described with reference to FIGS.

[0028] The reception state determination unit 112 determines the reception state of the signal from the GNSS system 2. The reception state determination unit 112 determines the reception state of the signal from the GNSS system 2, for example, depending on whether or not the satellite orbit information SF is stored in the orbit information storage unit 116. Furthermore, for example, when the number SN of satellites used to calculate the position information PS is three or less, the reception state determination unit 112 determines that the reception state of the position signal SP is not good.

[0029] For example, when the number SN of satellites used to calculate the position information PS is four or more, the reception state determination unit 112 executes the following process. That is, for example, when the orbit information SF is stored in the orbit information storage unit 116, the reception state determination unit 112 determines that the reception state of the position signal SP is good if the S / N ratio of the position signal SP is equal to or greater than the first threshold value TH1. The first threshold value TH1 is, for example, "10." The orbit information SF being stored in the orbit information memory unit 116 means that the orbit information SF of each satellite is stored in the orbit information memory unit 116 for all satellites used to calculate the position information PS.

[0030] Furthermore, for example, when the orbit information SF is not stored in the orbit information storage unit 116, the reception state determination unit 112 determines that the reception state of the position signal SP is good if the S / N ratio of the position signal SP is equal to or greater than the second threshold value TH2. The second threshold value TH2 is greater than the first threshold value TH1. The second threshold value TH2 is, for example, "30." When the orbit information SF is not stored in the orbit information memory unit 116, it means that for the multiple satellites used to calculate the position information PS, the orbit information SF of at least one satellite is not stored in the orbit information memory unit 116. The processing of the reception state determination unit 112 will be further described with reference to FIG.

[0031] The acquisition unit 113 acquires position information PS according to the determination results of the movement determination unit 111 and the reception state determination unit 112. The position information PS corresponds to the position signal SP. The position signal SP is included in the GNSS signal received by the GNSS receiver 12 from the GNSS system 2. That is, for example, when the GNSS receiver 12 receives a GNSS signal from the GNSS system 2, the acquisition unit 113 acquires the position information PS based on the position signal SP included in the GNSS signal.

[0032] The acquisition unit 113 acquires the position information PS, for example, when the movement determination unit 111 determines that the pallet 4 is being moved by a forklift FL and the reception status determination unit 112 determines that the reception status of the position signal SP is good. When acquiring the position information PS, the acquiring unit 113 stores the acquired position information PS in the position information storage unit 117 .

[0033] Furthermore, for example, when the GNSS receiver 12 receives a GNSS signal from the GNSS system 2, the acquisition unit 113 acquires the orbit information SF based on the orbit signal SE included in the GNSS signal. When acquiring the orbit information SF, the acquiring unit 113 stores the acquired orbit information SF in the orbit information storage unit 116 .

[0034] Furthermore, when a predetermined time has elapsed since the acquisition unit 113 acquired the orbit information SF, the acquisition unit 113 updates the orbit information SF stored in the orbit information storage unit 116. The predetermined time is, for example, four hours. In other words, when a predetermined time has elapsed since the acquisition unit 113 acquired the orbit information SF, the acquisition unit 113 causes the GNSS receiver 12 to receive a GNSS signal from the GNSS system 2, and acquires the orbit information SF based on the orbit signal SE included in the GNSS signal. Also, the acquisition unit 113 updates the orbit information SF stored in the orbit information storage unit 116 to the acquired orbit information SF. In addition, if the GNSS receiver 12 is unable to receive GNSS signals from the GNSS system 2 after a predetermined time has elapsed since the orbit information SF was acquired, the acquisition unit 113 deletes the orbit information SF stored in the orbit information memory unit 116.

[0035] The first communication control unit 114 controls the communication of the GNSS receiver 12 with the GNSS system 2 . For example, when the movement determination unit 111 determines that the pallet 4 is being moved by a forklift FL, the first communication control unit 114 powers on the GNSS receiver 12. In other words, when the movement determination unit 111 determines that the pallet 4 is being moved by a forklift FL, communication between the GNSS receiver 12 and the GNSS system 2 is established. For example, when the movement determination unit 111 determines that the pallet 4 is being moved by the truck TR, the first communication control unit 114 turns off the power of the GNSS receiver 12. Also, for example, when the movement determination unit 111 determines that the pallet 4 is not being moved, the first communication control unit 114 turns off the power of the GNSS receiver 12.

[0036] The second communication control unit 115 transmits the position information PS to the server device 3 via the communication interface 14, for example. For example, the second communication control unit 115 transmits the position information PS to the server device 3 every time the acquisition unit 113 acquires the position information PS. In this case, when the acquisition unit 113 acquires the position information PS, the second communication control unit 115 turns on the power of the communication interface 14. In other words, when the acquisition unit 113 acquires the position information PS, communication between the communication interface 14 and the server device 3 is established. Furthermore, the second communication control unit 115 may transmit the position information PS to the server device 3, for example, every time a predetermined period has elapsed. The predetermined period is, for example, 10 minutes.

[0037] Next, the processing of the movement determination unit 111 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing an example of the output of the gyro sensor 13 when the pallet 4 is transported by a forklift FL. Fig. 4 is a diagram showing an example of the output of the gyro sensor 13 when the pallet 4 is transported by a truck TR.

[0038] In each of the three graphs shown in Fig. 3, the horizontal axis represents time T. In the graph shown in the top part of Fig. 3, the vertical axis represents X-axis angular velocity αX. In the graph shown in the middle part of Fig. 3, the vertical axis represents Y-axis angular velocity αY. In the graph shown in the bottom part of Fig. 3, the vertical axis represents Z-axis angular velocity αZ. The units of the X-axis angular velocity αX, the Y-axis angular velocity αY, and the Z-axis angular velocity αZ are deg / sec. Graph G11 shown in the upper part of Fig. 3 shows the change in X-axis angular velocity αX. Graph G12 shown in the middle part of Fig. 3 shows the change in Y-axis angular velocity αY. Graph G13 shown in the lower part of Fig. 3 shows the change in Z-axis angular velocity αZ.

[0039] The X-axis amplitude WX1 indicates the amplitude of the X-axis angular velocity αX in graph G11. The Y-axis amplitude WY1 indicates the amplitude of the Y-axis angular velocity αY in graph G12. The Z-axis amplitude WZ1 indicates the amplitude of the Z-axis angular velocity αZ in graph G13. As shown in FIG. 3, the Z-axis amplitude WZ1 is larger than the X-axis amplitude WX1 and the Y-axis amplitude WY1, and satisfies, for example, the following formulas (1), (2), and (3). WZ1≧THA (1) WZ1 / WX1≧THB (2) WZ1 / WY1≧THB (3) The amplitude threshold THA is, for example, 50 deg / sec, and the amplitude ratio threshold THB is, for example, 5.

[0040] When the X-axis amplitude WX1, the Y-axis amplitude WY1, and the Z-axis amplitude WZ1 satisfy the formulas (1), (2), and (3), the movement determining unit 111 determines that the pallet 4 is transported by the forklift FL.

[0041] When the pallet 4 is transported by the forklift FL, the reason that the Z-axis amplitude WZ1 is larger than the X-axis amplitude WX1 and the Y-axis amplitude WY1 is as follows. The X-axis amplitude WX1 and the Y-axis amplitude WY1 correspond to the angle at which the pallet 4 is tilted with respect to the horizontal plane. Since multiple cargoes (e.g., cardboard boxes) may be stacked on the pallet 4, when the pallet 4 is transported by the forklift FL, the running path of the forklift FL is formed substantially horizontal so that the angle at which the pallet 4 is tilted with respect to the horizontal plane is equal to or smaller than a predetermined value. In other words, the X-axis angular velocity αX and the Y-axis angular velocity αY are limited to a predetermined range. On the other hand, when the forklift FL changes its direction of travel, the rotation angle about the Z-axis changes significantly, resulting in a Z-axis angular velocity αZ that is larger than the X-axis angular velocity αX and the Y-axis angular velocity αY. Therefore, as shown in FIG. 3, the Z-axis amplitude WZ1 becomes larger than the X-axis amplitude WX1 and the Y-axis amplitude WY1.

[0042] In each of the three graphs shown in Fig. 4, the horizontal axis represents time T. In the graph shown in the top part of Fig. 4, the vertical axis represents X-axis angular velocity αX. In the graph shown in the middle part of Fig. 4, the vertical axis represents Y-axis angular velocity αY. In the graph shown in the bottom part of Fig. 4, the vertical axis represents Z-axis angular velocity αZ. The units of the X-axis angular velocity αX, the Y-axis angular velocity αY, and the Z-axis angular velocity αZ are deg / sec. Graph G21 shown in the upper part of Fig. 4 shows the change in X-axis angular velocity αX. Graph G22 shown in the middle part of Fig. 4 shows the change in Y-axis angular velocity αY. Graph G23 shown in the lower part of Fig. 4 shows the change in Z-axis angular velocity αZ.

[0043] The X-axis amplitude WX2 indicates the amplitude of the X-axis angular velocity αX in graph G21. The Y-axis amplitude WY2 indicates the amplitude of the Y-axis angular velocity αY in graph G22. The Z-axis amplitude WZ2 indicates the amplitude of the Z-axis angular velocity αZ in graph G13. As shown in FIG. 4, the X-axis amplitude WX2, the Y-axis amplitude WY2, and the Z-axis amplitude WZ2 are smaller than the Z-axis amplitude WZ1 shown in FIG. 3, and satisfy, for example, the following formulas (4), (5), and (6). WZ2 <THA (4) WZ2 / WX2 <THB (5) WZ2 / WY2 <THB (6) The amplitude threshold THA is, for example, 50 deg / sec, and the amplitude ratio threshold THB is, for example, 5.

[0044] That is, when the pallet 4 is transported by a truck TR, the Z-axis amplitude WZ2 is approximately equal to or smaller than the X-axis amplitude WX2 and the Y-axis amplitude WY2. When the pallet 4 is transported by truck TR, the pallet 4 is placed on the bed of the truck TR. When the pallet 4 is transported by truck TR, the rotation angles around the X-axis and the Y-axis are smaller than when the pallet 4 is transported by forklift FL, but the moving speed is faster, so the frequency of vibration is higher. As a result, the X-axis amplitude WX2 is larger than the X-axis amplitude WX1, and the Y-axis amplitude WY2 is larger than the Y-axis amplitude WY1. On the other hand, since the truck TR mainly travels on public roads, the change per unit time in the traveling direction is small, so the Z-axis amplitude WZ2 is smaller than the X-axis amplitude WX2 and the Y-axis amplitude WY2. As a result, the X-axis amplitude WX2, the Y-axis amplitude WY2, and the Z-axis amplitude WZ2 satisfy the formulas (4), (5), and (6).

[0045] When the X-axis amplitude WX2, the Y-axis amplitude WY2, and the Z-axis amplitude WZ2 satisfy the formulas (4), (5), and (6), the movement determination unit 111 determines that the pallet 4 is transported by the truck TR. In addition, when the X-axis amplitude WX2, the Y-axis amplitude WY2, and the Z-axis amplitude WZ2 satisfy at least one of equations (4), (5), and (6), the movement determination unit 111 may determine that the pallet 4 is transported by the truck TR.

[0046] Next, the processing of the control unit 11 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 and Fig. 6 are flowcharts showing an example of the processing of the control unit 11. 5, in step S101, the movement determination unit 111 acquires the output of the gyro sensor 13. The output of the gyro sensor 13 is an X-axis angular velocity αX, a Y-axis angular velocity αY, and a Z-axis angular velocity αZ. Next, in step S103, the movement determination unit 111 calculates the X-axis amplitude WX, the Y-axis amplitude WY, and the Z-axis amplitude WZ. The X-axis amplitude WX indicates the amplitude of the X-axis angular velocity αX at a predetermined time. The Y-axis amplitude WY indicates the amplitude of the Y-axis angular velocity αY at a predetermined time. The Z-axis amplitude WZ indicates the amplitude of the Z-axis angular velocity αZ at a predetermined time. The predetermined time is, for example, 10 seconds.

[0047] Next, in step S105, the movement determination unit 111 determines whether or not each of the X-axis amplitude WX, the Y-axis amplitude WY, and the Z-axis amplitude WZ is less than the amplitude threshold value THA. When the movement determination unit 111 determines that each of the X-axis amplitude WX, the Y-axis amplitude WY, and the Z-axis amplitude WZ is less than the amplitude threshold value THA (step S105; YES), the process proceeds to step S107. Then, in step S107, the movement determination unit 111 determines that the pallet 4 has not been transported, and then the process ends. When the movement determination unit 111 determines that at least one of the X-axis amplitude WX, the Y-axis amplitude WY, and the Z-axis amplitude WZ is equal to or greater than the amplitude threshold value THA (step S105; NO), the process proceeds to step S109.

[0048] Then, in step S109, the movement determination unit 111 determines whether or not the following formula (7) is satisfied. (WZ / WX)≧THB (7) If the movement determination unit 111 determines that the formula (7) is not satisfied (step S109; NO), the process proceeds to step S111. Then, in step S111, the movement determination unit 111 determines that the pallet 4 is being transported by the second transport device TE2 such as a truck TR, and then the process ends. If the movement determination unit 111 determines that the formula (7) is satisfied (step S109; YES), the process proceeds to step S113.

[0049] Then, in step S113, the movement determination unit 111 determines whether or not the following formula (8) is satisfied. (WZ / WY)≧THB (8) If the movement determination unit 111 determines that the formula (8) is not satisfied (step S113; NO), the process proceeds to step S111. Then, in step S111, the movement determination unit 111 determines that the pallet 4 is being transported by the second transport device TE2 such as a truck TR, and then the process ends. If the movement determination unit 111 determines that the formula (8) is satisfied (step S113; YES), the process proceeds to step S115. Then, in step S115, the movement determination unit 111 determines that the pallet 4 is being transported by the first transport device TE1 such as a forklift FL, and then the process proceeds to step S117 in FIG.

[0050] Next, as shown in FIG. 6, in step S117, the first communication control unit 114 turns on the power of the GNSS receiver 12 and causes the GNSS receiver 12 to establish communication with the GNSS system 2. Next, in step S119, the reception state determination unit 112 causes the GNSS receiver 12 to receive GNSS signals from the GNSS system 2. The GNSS signals include a position signal SP, an orbit signal SE, and a number signal SM. The position signal SP corresponds to position information PS indicating the position of the GNSS receiver 12. The orbit signal SE indicates satellite orbit information SF. The number signal SM indicates the number SN of satellites used to calculate the position information PS.

[0051] Next, in step S121, the reception state determination unit 112 determines whether or not the number SN of satellites used to calculate the position information PS is four or more. If the reception state determination unit 112 determines that the number of satellites SN is three or less (step S121; NO), the process proceeds to step S123. Then, in step S123, the reception state determination unit 112 determines that the reception state is not good, and then the process ends. If the reception state determination unit 112 determines that the number of satellites SN is four or more (step S121; YES), the process proceeds to step S125. Then, in step S125, the reception state determination unit 112 determines whether or not the orbit information SF is stored in the orbit information storage unit 116 for each of the satellites used to calculate the position information PS.

[0052] If the reception state determination unit 112 determines that the orbit information SF is stored in the orbit information storage unit 116 for each of the satellites used to calculate the position information PS (step S125; YES), the process proceeds to step S129. If the reception state determination unit 112 determines that the orbit information SF is not stored in the orbit information storage unit 116 for at least one of the multiple satellites used to calculate the position information PS (step S125; NO), the process proceeds to step S127. Then, in step S127, the reception state determination unit 112 determines whether the S / N ratio of the position signal SP is equal to or greater than a second threshold value TH2. The second threshold value TH2 is, for example, "30." If the reception state determination unit 112 determines that the S / N ratio of the position signal SP is equal to or greater than the second threshold value TH2 (step S127; YES), the process proceeds to step S131. If the reception state determination unit 112 determines that the S / N ratio of the position signal SP is not equal to or greater than the second threshold value TH2 (step S127; NO), the process proceeds to step S123. Then, in step S123, the reception state determination unit 112 determines that the reception state is not good, and then the process ends.

[0053] If the result of step S125 is YES, then in step S129, the reception state determination unit 112 determines whether the SN ratio of the position signal SP is equal to or greater than a first threshold value TH1. The first threshold value TH1 is, for example, "10." If the reception state determination unit 112 determines that the SNR of the position signal SP is not equal to or higher than the first threshold value TH1 (step S129; NO), the process proceeds to step S123. Then, in step S123, the reception state determination unit 112 determines that the reception state is not good, and then the process ends. If the reception state determination unit 112 determines that the SNR of the position signal SP is equal to or greater than the first threshold value TH1 (step S129; YES), the process proceeds to step S131.

[0054] If the result is YES in step S127 and if the result is YES in step S129, then in step S131, the reception state determination unit 112 determines that the reception state is good. Then, in step S133, the acquisition unit 113 acquires the position information PS. Furthermore, the acquisition unit 113 stores the acquired position information PS in the position information storage unit 117. Furthermore, the second communication control unit 115 transmits the position information PS acquired by the acquisition unit 113 to the server device 3. Thereafter, the process ends.

[0055] [Present embodiment and effects] As explained above with reference to Figures 1 to 6, the position acquisition device 1 of this embodiment is attached to a pallet 4 being transported and acquires position information PS indicating the position of the pallet 4 from the GNSS system 2, and is equipped with a movement determination unit 111 that determines the movement state of the pallet 4, a reception state determination unit 112 that determines the reception state of the position signal SP from the GNSS system 2, and an acquisition unit 113 that acquires the position information PS depending on the determination result of the movement determination unit 111 and the determination result of the reception state determination unit 112.

[0056] That is, the position information PS is obtained according to the result of determining the moving state of the pallet 4 and the result of determining the receiving state of the position signal SP. Therefore, the position information PS can be acquired in an appropriate state. Therefore, for example, when the position signal from the satellite cannot be properly received, the execution of the positioning process is suppressed, so that unnecessary consumption of power can be suppressed.

[0057] The position acquisition device 1 also includes a gyro sensor 13 , and the movement determination unit 111 determines the movement state of the pallet 4 according to the output of the gyro sensor 13 . Therefore, since the movement state of the pallet 4 is determined according to the output of the gyro sensor 13, the movement state of the pallet 4 can be determined appropriately.

[0058] In addition, in the position acquisition device 1, the movement determination unit 111 determines, based on the output of the gyro sensor 13, whether the pallet 4 is being moved by the first conveying device TE1 or by the second conveying device TE2 which is different from the first conveying device TE1. Therefore, it can be properly determined whether the pallet 4 is being moved by the first transfer device TE1 or the second transfer device TE2, and therefore the movement state of the pallet 4 can be properly determined.

[0059] In the position acquisition device 1, the first conveyance device TE1 includes a forklift FL, and the second conveyance device TE2 includes a truck TR. Therefore, it is possible to properly determine whether the pallet 4 is being moved by the forklift FL or the truck TR, depending on the output of the gyro sensor 13. Therefore, the movement state of the pallet 4 can be properly determined.

[0060] In addition, in the position acquisition device 1, when the movement determination unit 111 determines that the pallet 4 is being moved by the first conveying device TE1, the reception status determination unit 112 determines the reception status of the position signal SP, and when the movement determination unit 111 determines that the pallet 4 is being moved by the second conveying device TE2, the reception status determination unit 112 does not determine the reception status of the position signal SP. Therefore, when the pallet 4 is being moved by the second conveyance device TE2, the reception state of the position signal SP is not determined. When the pallet 4 is being moved by, for example, a truck TR as the second conveyance device TE2, the pallet 4 is covered with a metal cover, so there is a high possibility that the position signal SP cannot be received. Therefore, when the position signal from the satellite cannot be properly received, the execution of the positioning process can be suppressed.

[0061] The position acquisition device 1 also includes an orbit information memory unit 116, an acquisition unit 113 acquires satellite orbit information SF from the GNSS system 2 and stores the orbit information SF in the orbit information memory unit 116, and a reception status determination unit 112 determines the reception status of the position signal SP depending on whether or not the orbit information SF is stored in the orbit information memory unit 116. Therefore, since the reception state of the position signal SP is determined depending on whether or not the orbit information SF is stored, the reception state of the position signal SP can be determined appropriately.

[0062] In addition, in the position acquisition device 1, when the orbit information SF is stored in the orbit information memory unit 116, the reception condition determination unit 112 determines that the reception condition of the position signal SP is good if the S / N ratio of the position signal SP is greater than or equal to the first threshold value TH1. Therefore, when the orbit information SF is stored, by setting the first threshold value TH1 to an appropriate value, it is possible to properly determine whether the reception state of the position signal SP is good or not.

[0063] In addition, in the position acquisition device 1, when the orbit information SF is not stored in the orbit information memory unit 116, the reception condition determination unit 112 determines that the reception condition of the position signal SP is good if the S / N ratio of the position signal SP is equal to or greater than a second threshold value TH2 that is greater than the first threshold value TH1. Therefore, when the orbit information SF is not stored, by setting the second threshold TH2 to an appropriate value larger than the first threshold TH1, it is possible to properly determine whether the reception state of the position signal SP is good or not.

[0064] The memory 11B having the control program PG recorded therein in this embodiment is attached to the pallet 4 being transported, and the position acquisition device 1 which acquires position information PS indicating the position of the pallet 4 from the GNSS system 2 has a processor 11A, and causes the processor 11A to function as a movement determination unit 111 which determines the movement state of the pallet 4, a reception state determination unit 112 which determines the reception state of the position signal SP from the GNSS system 2, and an acquisition unit 113 which acquires the position information PS depending on the determination results of the movement determination unit 111 and the reception state determination unit 112. Therefore, the memory 11B in which the control program PG according to this embodiment is recorded can achieve the same effects as the position acquisition device 1 according to this embodiment.

[0065] [Other embodiments] The above-described embodiment is a preferred embodiment, however, the present invention is not limited to the above-described embodiment and various modifications are possible without departing from the scope of the present invention.

[0066] In this embodiment, a case will be described in which the "object to be transported" is a pallet 4, but the embodiment is not limited to this. The "object to be transported" may be a so-called "cage cart." A "cage cart" is also called a cage dolly, cargo container, etc. Furthermore, the "object to be transported" may be cargo placed on the pallet 4.

[0067] In this embodiment, the first conveying device TE1 is a forklift FL, and the second conveying device TE2 is a truck TR, but the embodiment is not limited to this. The first conveying device TE1 may be, for example, a dolly. The second conveying device TE2 may be, for example, a train.

[0068] In this embodiment, the case where the "recording medium" is the memory 11B will be described, but the embodiment is not limited to this. The "recording medium" may be any recording medium on which the control program PG is recorded so as to be readable by a computer. For example, the recording medium may be a magnetic or optical recording medium or a semiconductor memory device. Specific examples include portable or fixed recording media such as a flexible disk, HDD, CD-ROM (Compact Disk Read Only Memory), DVD, Blu-ray (registered trademark) Disc, magneto-optical disk, flash memory, and card-type recording medium. The recording medium may also be a non-volatile storage device such as a RAM, ROM, or HDD, which is an internal storage device provided in the position acquisition device 1. The control program PG can be stored in a server device or the like, and each functional unit of the position acquisition device 1 can be realized by downloading the control program PG from the server device to the position acquisition device 1.

[0069] Moreover, each functional unit shown in FIG. 1 indicates a functional configuration, and the specific implementation form is not particularly limited. In other words, it is not necessarily necessary to implement hardware corresponding to each functional unit individually, and it is also possible to implement a configuration in which one processor executes a program to realize the functions of multiple functional units. Also, some of the functions realized by software in the above embodiment may be realized by hardware, or some of the functions realized by hardware may be realized by software. In addition, the specific detailed configuration of each unit of the position acquisition device 1 can be arbitrarily changed within the scope of the gist.

[0070] In addition, the processing units in the flowcharts shown in Figures 5 and 6 are divided according to the main processing contents in order to make the processing of the control unit 11 easier to understand. There is no limitation to the manner of division or names of the processing units shown in the flowcharts in Figures 5 and 6, and the processing units can be divided into more processing units according to the processing contents, or one processing unit can be divided to include more processes. In addition, the processing order of the above flowcharts is not limited to the example shown in the figures. [Explanation of symbols]

[0071] 1...position acquisition device, 11...control unit, 12...GNSS receiver, 13...gyro sensor, 14...communication interface, 15...battery, 11A...processor, 11B...memory (recording medium), 111...movement determination unit, 112...reception status determination unit, 113...acquisition unit, 114...first communication control unit, 115...second communication control unit, 116...trajectory information storage unit (storage unit), 117...position information storage unit, 2...GNSS system, 3...server device, 4...pallet (object to be transported), FL...forklift (first transport device), PG...control program (position acquisition program), SP...position signal, SE...trajectory signal, SM...number signal, PS...position information, SF...trajectory information, SN...number, TE1...first transport device, TE2...second transport device, TH1...first threshold, TH2...second threshold, THA...amplitude threshold, THB...amplitude ratio threshold, TR...truck (second transport device).

Claims

1. A position acquisition device that is attached to an object to be transported and acquires position information indicating a position of the object from a GNSS system, A movement determination unit that determines a movement state of the object; A reception state determination unit that determines a reception state of a position signal from the GNSS system; an acquisition unit that acquires the location information according to a determination result of the movement determination unit and a determination result of the reception state determination unit; A position acquisition device comprising:

2. Equipped with a gyro sensor, The movement determination unit determines a movement state of the object according to an output of the gyro sensor. The position acquisition device according to claim 1 .

3. The movement determination unit determines whether the object is being moved by a first conveying device or a second conveying device different from the first conveying device, according to an output of the gyro sensor. The position acquisition device according to claim 2 .

4. the first transport device includes a forklift; the second transport device includes a truck; The position acquisition device according to claim 3 .

5. When the movement determination unit determines that the object is being moved by the first conveying device, the reception state determination unit determines a reception state of the position signal, When the movement determination unit determines that the object is being moved by the second conveying device, the reception state determination unit does not determine the reception state of the position signal. The position acquisition device according to claim 3 or 4.

6. A memory unit is provided, The acquisition unit acquires satellite orbit information from the GNSS system, and stores the orbit information in the storage unit; the reception state determination unit determines a reception state of the position signal depending on whether the orbit information is stored in the storage unit. The position acquisition device according to claim 1 .

7. 7. The position acquisition device according to claim 6, wherein, when the orbit information is stored in the memory unit, the reception state determination unit determines that the reception state of the position signal is good if the signal-to-noise ratio of the position signal is equal to or greater than a first threshold value.

8. 8. The position acquisition device according to claim 7, wherein when the orbit information is not stored in the memory unit, the reception condition determination unit determines that the reception condition of the position signal is good if the signal-to-noise ratio of the position signal is equal to or greater than a second threshold value that is greater than the first threshold value.

9. A position acquisition device is attached to the object to be transported and acquires position information indicating the position of the object from the GNSS system, the position acquisition device comprising: a processor; The processor, A movement determination unit that determines a movement state of the object; A reception state determination unit that determines a reception state of a signal from the GNSS system; and an acquisition unit that acquires the location information in accordance with a determination result of the movement determination unit and a determination result of the reception state determination unit; A recording medium having a location acquisition program recorded thereon, the location acquisition program causing the device to function as a location acquisition device.

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