Positioning device

Abstract

To provide a positioning device capable of improving positioning accuracy even when an observation station is distant or even when some time has elapsed since last updating due to a long update interval of the observation data.SOLUTION: A positioning device for positioning the location of a movable body in a RTK-GNSS (Real Time Kinematic-Global Navigation Satellite System) for each positioning cycle comprises a data receiving unit for receiving observation data from an observation station which obtains the observation data on a plurality of positioning satellites and whose installation location has already been known; a signal receiving unit for receiving positioning signals from the plurality of positioning satellites; a positioning unit for positioning the location of the movable body, by a relative positioning where an installation location is regarded as a reference location with the use of the received observation data and the received positioning signals; and a determination unit for determining one of a fixing state or a floating state at the time of positioning. When the determination unit determines that it is the floating state, the positioning unit positions the location of the movable body and outputs it, by the relative positioning where the location of the movable body, positioned in a positioning cycle in which it is determined to be the fixing state last, is used as a reference location instead of the installation location.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a positioning device. [Background technology]

[0002] Conventionally, there has been a work vehicle equipped with a positioning unit that measures the carrier phase of transmission signals sent from multiple satellites, a relative displacement calculation unit that uses the carrier phase output from the positioning unit to determine the relative positional displacement of the vehicle body from a specific position that has been determined in advance, and an automatic driving control unit that controls the driving state of the vehicle body based on the calculation results of the relative displacement calculation unit so that the vehicle body drives along a predetermined linear target route (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-201612 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional work vehicle relative displacement calculation units have limitations in positioning accuracy because they do not use satellite information observed at reference stations (observation stations) or location information indicating the exact location of the reference stations. In addition, it is possible to obtain observation data from multiple positioning satellites and perform positioning using RTK-GNSS (Real Time Kinematic-Global Navigation Satellite System) using information from observation stations whose exact installation locations are known. Such observation stations include electronic reference points installed by the Geospatial Information Authority of Japan.

[0005] However, when the observation station is far away or when the observation data is updated at long intervals and a long time has passed since the last update, a fixed state cannot be obtained and the positioning accuracy decreases, resulting in a floating state.

[0006] Therefore, an object of the present invention is to provide a positioning device that can improve positioning accuracy even when the observation station is far away or when the update interval of the observation data is long and a long time has passed since the update. [Means for solving the problem]

[0007] A positioning device of an embodiment of the present invention is a positioning device that is mounted on a moving body and locates a position of the moving body using RTK-GNSS at every predetermined positioning cycle, and includes an observation data receiving unit that acquires observation data for a plurality of positioning satellites and receives the observation data from an observation station whose installation position is known, a positioning signal receiving unit that receives positioning signals from the plurality of positioning satellites, a positioning unit that uses the observation data received by the observation data receiving unit and the positioning signal received by the positioning signal receiving unit to locate the position of the moving body by relative positioning with the installation position as a reference position, and a state determination unit that determines whether the moving body was in a fixed state or a floating state when the positioning unit located the position of the moving body, when it is determined by the state determination unit that it was in the floating state, locates the position of the moving body by relative positioning using the position of the moving body measured in the positioning cycle in which it was last determined to be in the fixed state as the reference position instead of the installation position, and outputs the position as data representing the position of the moving body. Effect of the Invention

[0008] It is possible to provide a positioning device that can improve positioning accuracy even when the observation station is far away or when the update interval of the observation data is long and a long time has passed since the update. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a positioning system 1 including a positioning device 100 according to an embodiment. [Diagram 2] 1 is a diagram illustrating an example of the configuration of a positioning device 100. [Diagram 3]FIG. 4 is a flowchart showing the processing executed by the control device 130. [Figure 4] FIG. 13 is a diagram showing an example of a horizontal error of a position estimation result. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment to which the positioning device of the present invention is applied will be described.

[0011] <Embodiment> FIG. 1 is a diagram showing a positioning system 1 including a positioning device 100 according to an embodiment. In FIG. 1, the horizontal axis represents the time axis. Here, as an example, a form in which the positioning device 100 is mounted on a drone 20 as an example of a moving body will be described. The positioning system 1 enables highly accurate position measurement by RTK-GNSS (Real Time Kinematic-Global Navigation Satellite System). In positioning by RTK-GNSS, a positioning signal output from a positioning satellite 5 is received by an observation station 10 and a positioning device 100 mounted on the drone 20, the distance between the positioning satellite 5 and the positioning device 100 is measured, and three-dimensional coordinates of the positioning device 100 are calculated by solving simultaneous equations for the multiple positioning satellites 5.

[0012] Here, a form using GPS (Global Positioning System), which is an example of GNSS, is described, so the positioning signal output from the positioning satellite 5 is a GPS signal. However, the GNSS is not limited to GPS, and three-dimensional coordinates may be calculated using GLONASS, Beidou (BeiDou-2, Compass), Galileo, or other GNSS.

[0013] In the RTK-GNSS, the positioning device 100 uses observation data received from the observation station 10 and positioning signals received from the positioning satellite 5 to perform relative positioning using the installation position of the observation station 10 as a reference position to determine the position of the positioning device 100. Here, the position of the positioning device 100 is synonymous with the position of the drone 20.

[0014] The observation station 10 knows its exact installation location (coordinates representing latitude, longitude, and altitude), and receives (acquires) GPS radio waves from multiple positioning satellites 5 to measure the distance to each positioning satellite 5. The observation station 10 constantly outputs observation data including position data representing its installation location and distance data representing the distance to each positioning satellite 5. The distance data included in the observation data is updated at predetermined intervals. This is because the positional relationship between the observation station 10 and the multiple positioning satellites 5 changes. Such observation stations 10 may include electronic reference points of the Geospatial Information Authority of Japan.

[0015] The drone 20 is an example of a moving body, and is equipped with the positioning device 100. The drone 20 is equipped with, as an example, a navigation control device that performs navigation control of the drone 20 based on the coordinates of the drone 20 measured by the positioning device 100.

[0016] When calculating the three-dimensional coordinates of the positioning device 100, the positioning device 100 judges whether the state is a fixed state in which a fixed solution can be obtained, or a floating state in which a fixed solution cannot be obtained. For example, even if the state is a fixed state at time t-1 shown in FIG. 1, it may change to a floating state at time t, which is the next positioning period.

[0017] Generally, in a fixed state, RTK-GNSS can obtain a high positioning accuracy of about several centimeters by performing positioning based on observation data from the observation station 10. However, in a floating state, the positioning accuracy may deteriorate to about several meters due to factors such as the long distance to the observation station 10 and the long time elapsed since the observation data was last updated. The positioning device 100 of the embodiment improves the positioning accuracy in the floating state to about several centimeters.

[0018] <Configuration of positioning device 100> 2 is a diagram showing an example of the configuration of the positioning device 100. The positioning device 100 includes an observation data receiving unit 110, a positioning signal receiving unit 120, and a control device 130. The observation data receiving unit 110 is a receiver that receives observation data from the observation station 10 via a mobile phone line. The positioning signal receiving unit 120 is a GPS receiver that receives positioning signals output from at least four or more positioning satellites 5.

[0019] As an example, the positioning device 100 employs single-frequency RTK, which is a method of receiving a single-frequency positioning signal (GPS signal), receiving observation data from the observation station 10 via a mobile phone line, and locating the position of the positioning device 100 based on the received positioning signal (GPS signal) and the received observation data.

[0020] In order to position the position of the drone 20 using RTK-GNSS for each positioning period, the positioning device 100 cancels out the error contained in the positioning signal based on the received positioning signal and the received observation data, determines the relative position of the positioning device 100 with respect to the installation position of the observation station 10 based on the positioning signal with the error canceled out, and determines the position of the positioning device 100 based on the determined relative position and the installation position of the observation station 10.

[0021] The control device 130 has a main control unit 131, a positioning unit 132, a state determination unit 133, and a memory 134. The control device 130 is realized by a computer or microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input / output interface, an internal bus, and the like. The main control unit 131, the positioning unit 132, and the state determination unit 133 are functional blocks showing the functions of a program executed by the control device 130. The memory 134 is a functional representation of the memory of the control device 130.

[0022] The main control unit 131 is a processing unit that controls the processing of the control device 130, and executes processing other than that executed by the positioning unit 132 and the state determination unit 133. The main control unit 131 outputs, for example, a command to the observation data receiving unit 110 to receive observation data, and outputs a command to the positioning signal receiving unit 120 to receive a positioning signal.

[0023] The positioning unit 132 uses the observation data received by the observation data receiving unit 110 and the positioning signal received by the positioning signal receiving unit 120 to locate the position of the positioning device 100 by relative positioning using the installation position of the observation station 10 as the reference position.

[0024] In addition, when the state determination unit 133 determines that the positioning device 100 is in a floating state, the positioning unit 132 determines the position of the positioning device 100 by relative positioning, using the position of the positioning device 100 determined in the positioning cycle in which the positioning device 100 was last determined to be in a fixed state as a reference position instead of the installation position of the observation station 10, and outputs the position of the positioning device 100 as data representing the position of the positioning device 100.

[0025] More specifically, when the state determination unit 133 determines that the positioning device 100 is in the floating state, in the relative positioning using the position of the positioning device 100 determined in the last positioning cycle determined to be in the fixed state as the reference position instead of the installation position of the observation station 10, the positioning unit 132 cancels the error contained in the positioning signal based on the observation data received by the observation station 10 in the current positioning cycle and the positioning signal received by the positioning signal receiving unit 120 in the current positioning cycle, obtains the position of the positioning device 100 relative to the reference position using the positioning signal with the error canceled, and determines the position of the positioning device 100 based on the reference position and the position of the positioning device 100 relative to the reference position. The determined position of the positioning device 100 can be obtained by adding the difference of the coordinates representing the position of the positioning device 100 relative to the reference position to the coordinates of the reference position. The positioning unit 132 outputs the data representing the determined position of the positioning device 100.

[0026] In addition, when the state determination unit 133 determines that the positioning unit 132 is in a fixed state, the positioning unit 132 uses the observation data received by the observation data receiving unit 110 and the positioning signal received by the positioning signal receiving unit 120, and outputs the position of the positioning device 100, which has been positioned by relative positioning using the installation position of the observation station 10 as a reference position, as data representing the position of the positioning device 100.

[0027] More specifically, when the state determination unit 133 determines that the positioning unit 132 is in the fixed state, the positioning unit 132 cancels out the error contained in the positioning signal using the observation data received by the observation data receiving unit 110 and the positioning signal received by the positioning signal receiving unit 120, obtains the position of the positioning device 100 relative to a reference position using the positioning signal with the error canceled, and determines the position of the positioning device 100 based on the reference position and the position of the positioning device 100 relative to the reference position. The determined position of the positioning device 100 can be obtained by adding the difference between the coordinates of the reference position and the coordinates representing the position of the positioning device 100 relative to the reference position. The positioning unit 132 outputs the data representing the determined position of the positioning device 100. The reference position in this case is the installation position of the observation station 10.

[0028] The state determination unit 133 determines whether the state was a fixed state or a floating state when the positioning unit 132 located the position (three-dimensional coordinates) of the positioning device 100. Depending on whether a fix solution was obtained when the positioning device 100 was located, the state determination unit 133 determines whether the state was a fixed state in which a fix solution was obtained, or a floating state in which a fix solution was not obtained.

[0029] The memory 134 stores programs and data used by the main control unit 131, the positioning unit 132, and the status determination unit 133 when executing the above-mentioned processes, and also temporarily stores the positioning signals and observation data received by the observation data receiving unit 110 and the positioning signal receiving unit 120.

[0030] <Processing Executed by the Control Device 130 of the Positioning Device 100> FIG. 3 is a flowchart showing the process executed by the control device 130. As shown in FIG.

[0031] When the flow starts, the main control unit 131 outputs a command to the observation data receiving unit 110 to receive observation data (step S1). This causes the observation data receiving unit 110 to receive the observation data.

[0032] The main control unit 131 outputs a command to the positioning signal receiving unit 120 to receive the positioning signal (step S2). This causes the positioning signal receiving unit 120 to receive the positioning signal. The distance to the positioning satellite 5 included in the observation data received by the command output in step S1 and the distance to the positioning satellite 5 obtained by the positioning signal received by the command output in step S2 are distances obtained based on the positioning signals received by the observation data receiving unit 110 and the positioning signal receiving unit 120 at the same time.

[0033] The positioning unit 132 uses the observation data received by the observation data receiving unit 110 and the positioning signal received by the positioning signal receiving unit 120 to locate the position of the positioning device 100 by relative positioning using the installation position of the observation station 10 as a reference position (step S3). The positioning in step S3 is a process performed by RTK-GNSS, and the position thus determined represents an estimated position of the positioning device 100 estimated by the observation data and the positioning signal.

[0034] The state determination unit 133 determines whether the state was a fixed state or a floating state when the positioning unit 132 measured the position (three-dimensional coordinates) of the positioning device 100 in step S3 (step S4).

[0035] If the state determination unit 133 determines in step S4 that the state is fixed, the positioning unit 132 outputs data representing the position of the positioning device 100 determined in step S3 as data representing the current position of the positioning device 100 (step S5).

[0036] On the other hand, if the state determination unit 133 determines that the positioning device 100 was in a floating state in step S4, the positioning unit 132 determines the position of the positioning device 100 by relative positioning using the position of the positioning device 100 determined in the positioning cycle in which the positioning device 100 was last determined to be in a fixed state as a reference position instead of the installation position of the observation station 10, and outputs the position as data representing the position of the positioning device 100 (step S6). The positioning in step S6 is a process performed by RTK-GNSS using the position of the positioning device 100 determined in the positioning cycle in which the positioning device 100 was last determined to be in a fixed state as a reference position, and the position thus determined represents an estimated position of the positioning device 100 estimated by the observation data and the positioning signal.

[0037] When the process of step S5 or S6 ends, the main control unit 131 determines whether or not to end the series of processes (step S7). The series of processes ends when, for example, the power supply of the drone 20 is turned off. When the main control unit 131 determines that the series of processes is not to end, the flow returns to step S1. When the power supply of the drone 20 is turned off, the main control unit 131 ends the series of processes (end).

[0038] <Horizontal error of position estimation result> Fig. 4 is a diagram showing an example of horizontal error in the position estimation result. Fig. 4(A) shows the result of estimating the position of the positioning device 100 by fixing the position of the positioning device 100 and performing positioning for 5 minutes. The positioning period is 1 second as an example. As shown in Fig. 4(A), the standard deviation of the horizontal error is 1.98 cm.

[0039] For comparison, Fig. 4(B) shows the results of a comparative example in which the reference position for positioning is fixed to the installation position of the observation station 10, the position of the positioning device is fixed, positioning is performed for 5 minutes, and the position of the positioning device is estimated. The positioning period is, for example, 1 second. As shown in Fig. 4(B), the standard deviation of the horizontal error is 14.86 cm.

[0040] In this way, when the positioning device 100 enters a floating state, it determines the position of the positioning device 100 by relative positioning, using the position of the positioning device 100 determined in the positioning cycle in which it was last determined to be in a fixed state as the reference position instead of the installation position of the observation station 10, thereby reducing the horizontal error of the position estimation result to approximately 13.3% compared to when the reference position is fixed to the installation position of the observation station 10.

[0041] In the comparative positioning device, when the observation station 10 is far away or when the device becomes floating due to the passage of time since the observation data update time, the reference position is fixed to the installation position of the observation station 10, resulting in a large measurement error. In contrast, when the positioning device 100 becomes floating, the position of the positioning device 100 measured in the positioning cycle in which it was last determined to be in a fixed state is used as the reference position instead of the installation position of the observation station 10, which is thought to be the reason for the above-mentioned difference.

[0042] Therefore, it is possible to provide a positioning device 100 that can improve positioning accuracy even when the observation station 10 is far away or when the update interval of the observation data is long and a long time has passed since the update.

[0043] In addition, when the positioning device 100 is in a floating state, it is possible to use the measurement values ​​of a gyro sensor, an acceleration sensor, etc. to estimate the current position of the positioning device 100 with high accuracy, but the positioning device 100 can improve the positioning accuracy without using the measurement values ​​of a gyro sensor, an acceleration sensor, etc.

[0044] Furthermore, mounting a measuring device such as a gyro sensor or acceleration sensor on a moving body such as the drone 20 causes problems such as increased weight, securing space for mounting, and difficulty in mounting the device itself when the moving body is small. In contrast, when the positioning device 100 is installed on a moving body such as the drone 20, there is no need to mount a measuring device such as a gyro sensor or acceleration sensor, and therefore the above-mentioned various problems do not occur, and the device can be realized at low cost.

[0045] The above describes an exemplary embodiment of a positioning device of the present invention. However, the present invention is not limited to the specifically disclosed embodiment, and various modifications and variations are possible without departing from the scope of the claims. [Explanation of symbols]

[0046] 1 Positioning System 5. Positioning satellites 10 Observation Stations 20. Drone 100 Positioning device 110 Observation data receiving unit 120 Positioning signal receiver 130 Control device 131 Main control unit 132 Positioning unit 133 Status determination unit 134 Memory

Claims

1. A positioning device that is mounted on a moving object and measures a position of the moving object by an RTK-GNSS at a predetermined positioning period, an observation data receiving unit that acquires observation data about a plurality of positioning satellites and receives the observation data from an observation station whose installation position is known; a positioning signal receiving unit that receives positioning signals from the plurality of positioning satellites; a positioning unit that uses the observation data received by the observation data receiving unit and the positioning signal received by the positioning signal receiving unit to measure the position of the moving object by relative positioning with the installation position as a reference position; a state determination unit that determines whether the moving object was in a fixed state or a floating state when the positioning unit determined the position of the moving object; Including, When the state determination unit determines that the moving body was in the floating state, the positioning unit determines the position of the moving body by relative positioning, using the position of the moving body determined in the positioning cycle in which the moving body was last determined to be in the fixed state as the reference position instead of the installation position, and outputs the positioning device as data representing the position of the moving body.

2. 2. The positioning device according to claim 1, wherein when the state determination unit determines that the fixed state has been established, the positioning unit uses the observation data received by the observation data receiving unit and the positioning signal received by the positioning signal receiving unit to output the position of the moving body determined by the relative positioning using the installation position as a reference position as data representing the position of the moving body.

3. 3. The positioning device according to claim 1, wherein, when the state determination unit determines that the positioning unit is in the fixed state, the positioning unit cancels out an error contained in the positioning signal using the observation data received by the observation data receiving unit and the positioning signal received by the positioning signal receiving unit, and outputs, using the positioning signal in which the error has been canceled, the position of the moving body determined by the relative positioning with the installation position as a reference position, as data representing the position of the moving body.

4. 4. The positioning device according to claim 1, wherein, when the state determination unit determines that the moving body was in the float state, in the relative positioning in which the position of the moving body measured in the positioning cycle in which the moving body was last determined to be in the fixed state is used as the reference position instead of the installation position, the positioning unit cancels out an error contained in the positioning signal based on the observation data received by the observation data receiving unit and the positioning signal received by the positioning signal receiving unit, determines the position of the moving body using the positioning signal in which the error has been canceled, and outputs the positioning signal as data representing the position of the moving body.

5. The positioning device according to claim 1 , wherein the positioning unit measures the position of the moving object by single-frequency RTK.

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