Position acquisition system and position acquisition method

Abstract

The present invention comprises: a first position detection unit that acquires the position of a mobile body that is moving; a second position detection unit that acquires the position of a target landing point set on the mobile body; a third position detection unit that acquires the position of an aircraft that lands on the target landing point; and a control unit that acquires positional relationships among the mobile body, the target landing point, and the aircraft on the basis of detection results of the first position detection unit, the second position detection unit, and the third position detection unit. The control unit acquires the relative positions of the mobile body and the aircraft on the basis of the position of the mobile body detected by the first position detection unit and the position of the aircraft detected by the third position detection unit, and acquires, as an offset position, the positional relationship between the mobile body and the target landing point on the basis of the position of the mobile body detected by the first position detection unit and the position of the target landing point detected by the second position detection unit.

Description

Location acquisition system and location acquisition method

[0001] The present disclosure relates to a location acquisition system and a location acquisition method.

[0002] Conventionally, an automatic landing system for landing a vertical take-off and landing aircraft at a landing target point provided on a ship has been known (see, for example, Patent Document 1). The automatic landing system for a vertical take-off and landing aircraft disclosed in Patent Document 1 controls the vertical take-off and landing aircraft so that the relative position between the vertical take-off and landing aircraft and the landing target point becomes zero.

[0003] Japanese Patent Application Laid-Open No. 2021-062719

[0004] In the automatic landing system for a vertical take-off and landing aircraft disclosed in Patent Document 1, when the vertical take-off and landing aircraft is in approach mode away from the landing target point, the relative position is calculated based on the position of the vertical take-off and landing aircraft acquired by a navigation device and the position of the ship acquired by the navigation device. On the other hand, when the automatic landing system is in hovering mode, when the vertical take-off and landing aircraft is approaching the landing target point, the relative position is calculated based on an image of the landing target point captured by a camera mounted on the vertical take-off and landing aircraft. This requires multiple processes for calculating the relative position between the vertical take-off and landing aircraft and the landing target point, which creates a problem of system complexity. To simplify the system, it is conceivable to calculate the relative position using a navigation device in hovering mode, as in approach mode. However, this reduces the accuracy of position detection, making it difficult to accurately land the vertical take-off and landing aircraft at the landing target point.

[0005] Therefore, an object of the present disclosure is to provide a position acquisition system and a position acquisition method that can acquire the positions of an aircraft and a target landing point with high accuracy while simplifying the system.

[0006] The position acquisition system of the present disclosure comprises a first position detection unit that acquires the position of a moving mobile body, a second position detection unit that acquires the position of a target landing point set for the mobile body, a third position detection unit that acquires the position of an aircraft landing at the target landing point, and a control unit that acquires the positional relationship between the mobile body, the target landing point, and the aircraft based on the detection results of the first position detection unit, the second position detection unit, and the third position detection unit, and the control unit acquires the relative position between the mobile body and the aircraft based on the position of the mobile body detected by the first position detection unit and the position of the aircraft detected by the third position detection unit, and acquires the positional relationship between the mobile body and the target landing point as an offset position based on the position of the mobile body detected by the first position detection unit and the position of the target landing point detected by the second position detection unit.

[0007] The position acquisition method disclosed herein is a position acquisition method executed by a position acquisition system that acquires the positional relationship between the position of a moving mobile body, the position of a target landing point set for the mobile body, and the position of an aircraft landing at the target landing point, and acquires the relative position between the mobile body and the aircraft based on the position of the mobile body and the position of the aircraft, and acquires the positional relationship between the mobile body and the target landing point as an offset position based on the position of the mobile body and the position of the target landing point.

[0008] According to the present disclosure, the positions of the aircraft and the target landing point can be obtained with high accuracy.

[0009] Fig. 1 is a schematic diagram showing an example of a position acquisition system according to this embodiment. Fig. 2 is a flowchart relating to a position acquisition method according to this embodiment. Fig. 3 is an explanatory diagram relating to position acquisition according to this embodiment. Fig. 4 is a flowchart relating to another example of a position acquisition method according to this embodiment.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, this disclosure is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially identical. Furthermore, the components described below can be combined as appropriate, and when there are multiple embodiments, the respective embodiments can also be combined.

[0011] 1 is a schematic diagram showing an example of a position acquisition system according to this embodiment. The position acquisition system 100 is a system for acquiring the positional relationship between an aircraft 1 and a ship 5, and also a system for acquiring the positional relationship between the ship 5 and a target landing point where the aircraft 1 will land.

[0012] The aircraft 1 is a rotary-wing aircraft (e.g., a helicopter, a drone, etc.). In this embodiment, the aircraft 1 is an unmanned aerial vehicle (UAV). The aircraft 1 may be any aircraft capable of forward, backward, sideways, turning, and hovering, and may be a manned aircraft. The aircraft 1 is equipped with a position acquisition system 100, and its flight is controlled based on position information acquired by the position acquisition system 100.

[0013] The target landing point is provided on the ship 5. Therefore, the aircraft 1 lands (docks) on the ship 5, which is a mobile body that moves on water. However, the target landing point is not limited to the ship 5, and may be provided on a mobile body that moves on land, such as a vehicle, or may be provided on stationary equipment or the ground.

[0014] The position acquisition system 100 according to this embodiment acquires the positional relationship between the aircraft 1 and the ship 5, which is a moving body, and also acquires the positional relationship between the ship 5 and a target landing point on the ship 5. As shown in Fig. 1 , the position acquisition system 100 is configured as a system provided across the aircraft 1, the ship 5, and a portable position detection device 120. Note that although this embodiment is applied to the ship 5 as a moving body, it may also be applied to a land vehicle such as a car as a moving body. First, the ship 5 will be described.

[0015] (Ship) As shown in FIG. 1 , the ship 5 includes a navigation device 60 , an RTK positioning processing unit (first position detection unit) 70 , a data transmission device 80 , and an operation display unit 90 .

[0016] The navigation device 60 is, for example, an inertial navigation system (INS) (registered trademark), and acquires the pitch and roll attitude angles, heading, speed, acceleration, and position coordinates in a global coordinate system of the ship 5. In the present embodiment, the navigation device 60 is described as being an inertial navigation system, but is not particularly limited thereto, and any navigation device 60 may be used. In the present embodiment, the navigation device 60 is an inertial navigation system including a GPS (Global Positioning System) to improve the accuracy of position measurement. In the present embodiment, the navigation device 60 is described as being an inertial navigation system including a GPS, but is not particularly limited to a GPS, and any system capable of measuring position with high accuracy may be used. For example, a system using a quasi-zenith satellite system may be used. Alternatively, a configuration omitting a GPS or the like may be used as long as the position can be measured with high accuracy using only the navigation device 60. The navigation device 60 may also acquire at least some of the various data using a sensor.

[0017] The RTK positioning processing unit 70 is included in the position acquisition system 100, which will be described later, and is a positioning method that uses a satellite positioning system including artificial satellites. The RTK positioning processing unit 70 is an RTK (Real Time Kinematic)-GPS, which uses the position of the artificial satellite as a reference point and measures the position coordinates of the ship 5 based on carrier phase data transmitted from the artificial satellite to the ship 5. RTK-GPS receives signals from multiple artificial satellites using receivers in two mobile stations. RTK-GPS corrects for deviations and obtains high-precision position information by exchanging information between two receivers based on signals received from multiple artificial satellites. RTK-GPS is capable of suppressing errors to within a few centimeters.

[0018] The data transmission device 80 is included in a position acquisition system 100 (described later), and exchanges various signals via wireless communication with a data transmission device 40 mounted on the aircraft 1. The data transmission device 80 transmits the position coordinates of the ship 5 measured by the RTK positioning processing unit 70 to the data transmission device 40.

[0019] The operation and display unit 90 is a user interface through which an operator on board the vessel 5 grasps the control status and inputs various instructions. The instructions input on the operation and display unit 90 are transmitted from the data transmission device 80 to the data transmission device 40. The control status of the aircraft 1 is transmitted from the data transmission device 40 to the data transmission device 80. In other words, the data transmission devices 40 and 80 are capable of two-way communication.

[0020] (Aircraft) Next, a description will be given of the aircraft 1. As shown in Fig. 1 , the aircraft 1 includes a navigation device 20, a control unit 30, a data transmission device 40, and an RTK positioning processing unit (third position detection unit) 50.

[0021] Like the navigation device 60, the navigation device 20 is, for example, an inertial navigation system including a GPS. Like the navigation device 60, the navigation device 20 may also be an inertial navigation system including a GPS or the like, or an inertial navigation system excluding a GPS or the like; there is no particular limitation. The navigation device 20 including a GPS acquires the pitch and roll attitude angles of the aircraft 1, the aircraft's heading, the aircraft's speed, the aircraft's acceleration, and position coordinates in the Earth's coordinate system. The navigation device 20 may also include an attitude angle sensor that detects the attitude angle of the aircraft 1, a speed detection sensor that detects the aircraft's speed, an acceleration detection sensor that detects the aircraft's acceleration, and a sensor that detects the aircraft's heading. The navigation device 20 outputs the acquired attitude angle, aircraft's speed, the aircraft's acceleration, and position coordinates of the aircraft 1 to the control unit 30.

[0022] The control unit 30 includes an integrated circuit such as a CPU (Central Processing Unit), etc. The control unit 30 has a guidance calculation unit 34 and a flight control unit 36.

[0023] The guidance calculation unit 34 calculates control variables for the aircraft 1 to guide the aircraft 1 to the target landing point. The control variables are variables for adjusting the aircraft speed, attitude angle, rate of change of attitude angle, etc. of the aircraft 1. To calculate the control variables, the guidance calculation unit 34 calculates the relative coordinate position between the aircraft 1 and the target landing point. Specifically, the guidance calculation unit 34 calculates the relative position between the aircraft 1 and the target landing point and the relative altitude between the aircraft 1 and the target landing point as the relative coordinate position. The guidance calculation unit 34 also calculates the relative speed between the aircraft 1 and the target landing point, etc. The relative position is the distance between the aircraft 1 and the target landing point of the ship 5 in the horizontal direction. To calculate the relative position between the aircraft 1 and the target landing point, the guidance calculation unit 34 uses the relative position between the aircraft 1 and the ship 5 and the offset position between the ship 5 and the target landing point, which are acquired by the position acquisition system 100 described below. The relative altitude is the distance between the aircraft 1 and the target landing point of the ship 5 in the vertical direction. The guidance calculation unit 34 calculates the relative altitude to the landing target point based on the altitude of the aircraft 1 detected by the altitude sensor 25.

[0024] The guidance calculation unit 34 also calculates the relative speed between the aircraft 1 and the target landing point. More specifically, the guidance calculation unit 34 calculates the relative speed between the aircraft 1 and the target landing point based on the relative position and the aircraft speed.

[0025] The guidance calculation unit 34 then calculates a control amount by feedback control (e.g., PID control) based on the relative position, relative altitude, relative speed, and aircraft acceleration. Note that the feedback control is not limited to PID control, but may be P control, PI control, PD control, etc. The guidance calculation unit 34 outputs the calculated control amount to the flight control unit 36.

[0026] The flight control unit 36 ​​controls each component of the aircraft 1 in accordance with the control amount calculated by the guidance calculation unit 34 to fly the aircraft 1. The flight control unit 36 ​​controls the blade pitch angle, rotation speed, etc. of each rotor in accordance with the control amount, and adjusts the aircraft speed, attitude angle, rate of change of attitude angle, etc. of the aircraft 1. In this way, the aircraft 1 is guided to the target landing point. Note that in this embodiment, the guidance calculation unit 34 is described as a functional unit separate from the flight control unit 36, but the flight control unit 36 ​​and the guidance calculation unit 34 may be an integrated functional unit. In other words, the processing of the guidance calculation unit 34 may be performed in the flight control unit 36.

[0027] The RTK positioning processing unit 50 employs a positioning method that uses a satellite positioning system including artificial satellites, similar to the above-described RTK positioning processing unit 70. The RTK positioning processing unit 50 is an RTK (Real Time Kinematic)-GPS, and measures the position coordinates of the aircraft 1 based on carrier wave phase data transmitted from the artificial satellite to the aircraft 1, using the position of the artificial satellite as a reference point.

[0028] The data transmission device 40, like the data transmission device 80 described above, is included in the position acquisition system 100 described below, and exchanges various signals with the data transmission device 80 installed on the ship 5 via wireless communication.

[0029] (Position Acquisition System) Next, a description will be given of the position acquisition system 100. The position acquisition system 100 includes an RTK positioning processing unit 50 and a data transmission device 40 of the aircraft 1, an RTK positioning processing unit 70 and a data transmission device 80 of the ship 5, and a portable position detection device 120.

[0030] The position detection device 120 is installed at a target landing point on the ship 5. The position detection device 120 has an operation button 121, an RTK positioning processing unit (second position detection unit) 122, and a data transmission device (communication unit) 123.

[0031] The operation button 121 is a user interface through which an operator on board the vessel 5 inputs data. The operation button 121 is a button that is operated to acquire the position of the position detection device 120.

[0032] The RTK positioning processing unit 122 employs a positioning method using a satellite positioning system including artificial satellites, similar to the above-described RTK positioning processing units 50 and 70. The RTK positioning processing unit 122 is an RTK (Real Time Kinematic)-GPS, and measures the position coordinates of the position detection device 120, i.e., the position coordinates of the target landing point, based on carrier wave phase data transmitted from the artificial satellite to the position detection device 120, using the position of the artificial satellite as a reference point.

[0033] Similar to the data transmission devices 40 and 80 described above, the data transmission device 123 exchanges various signals via wireless communication with the data transmission devices 40 and 80 mounted on the aircraft 1 and the ship 5. The data transmission device 123 transmits the position coordinates of the target landing point measured by the RTK positioning processing unit 122 to the data transmission device 80.

[0034] (Position Acquisition Method) Next, a position acquisition method executed by the position acquisition system 100 according to this embodiment will be described with reference to Figures 2 and 3. Figure 2 is a flowchart relating to the position acquisition method according to this embodiment. Figure 3 is an explanatory diagram relating to position acquisition according to this embodiment. The position acquisition method is a method for acquiring an offset position between the ship 5 and the target landing point P, which is necessary for calculating the relative position between the aircraft 1 and the target landing point P. In this embodiment, the position acquisition method is executed by the position detection device 120, and therefore the position detection device 120 functions as a control unit of the position acquisition system 100.

[0035] First, in the position acquisition method, the position detection device 120 is installed at the target landing point P. Next, the position detection device 120 determines whether the operation button 121 has been operated (step S1). If the position detection device 120 determines that the operation button 121 has not been operated (step S1: No), it repeats step S1 until the operation button 121 is operated. On the other hand, if the position detection device 120 determines in step S1 that the operation button 121 has been operated (step S1: Yes), it acquires position information (position coordinates) of the target landing point P (step S3).

[0036] After executing step S3, the position detection device 120 acquires the position information (position coordinates) of the ship 5 (step S5). In step S5, the position detection device 120 acquires the position coordinates of the ship 5 acquired by the RTK positioning processing unit 70 of the ship 5 via the data transmission device 80 and the data transmission device 123. Then, the position detection device 120 acquires an offset position (relative position) which is the distance between the ship 5 and the target landing point P, as shown in FIG. 3, from the acquired position information of the ship 5 and the acquired position information of the target landing point P (step S6). Thereafter, the position detection device 120 outputs the acquired offset position to the aircraft 1 (step S7). In step S7, the position detection device 120 transmits the acquired offset position to the aircraft 1 via the data transmission device 123 and the data transmission device 40. After executing step S7, the position acquisition system 100 ends the processing related to the position acquisition method.

[0037] As shown in Figure 3, the aircraft 1 offsets its position based on the acquired offset position (the relative position between the ship 5 and the target landing point P) relative to the relative position between the aircraft 1 and the ship 5, thereby acquiring the relative position between the aircraft 1 and the target landing point P on the ship 5, and performs flight control based on this relative position.

[0038] In this embodiment, the offset position is output from the position detection device 120 to the aircraft 1, but this configuration is not particularly limited. For example, the offset position may be acquired in the ship 5 and output from the ship 5 to the aircraft 1, or the offset position may be acquired in the aircraft 1. In these cases, the control unit 30 provided in the aircraft 1 and the ship 5 functions as the control unit of the position acquisition system 100.

[0039] Here, when the aircraft 1 lands at the target landing point P on the ship 5, there is a possibility that communication failure will occur between the aircraft 1 and the satellites used in the RTK-GPS at the target landing point P due to structures around the target landing point P or the like. Therefore, the position detection device 120 may evaluate the communication status with a satellite positioning system including multiple satellites at the target landing point P. If there is a satellite with which communication is unstable, the position detection device 120 may detect the position of the target landing point without using the positioning information of the unstable satellite. Hereinafter, with reference to FIG. 4 , another example of a position acquisition method executed by the position acquisition system 100 according to this embodiment will be described. FIG. 4 is a flowchart illustrating another example of the position acquisition method according to this embodiment. In FIG. 4 , after execution of step S1, the communication status with the satellite positioning system is evaluated. Note that, in the following description, descriptions of parts similar to those in FIG. 2 will be omitted.

[0040] In step S1, the position detection device 120 determines that the operation button 121 has been operated (step S1: Yes), and then determines whether there is any artificial satellite of a satellite positioning system with which communication becomes unstable (step S2). If the position detection device 120 determines that there is no artificial satellite of a satellite positioning system with which communication becomes unstable (step S2: Yes), the position detection device 120 proceeds to step S3. On the other hand, if the position detection device 120 determines that there is any artificial satellite of a satellite positioning system with which communication becomes unstable (step S2: No) in step S2, the position detection device 120 excludes the artificial satellite of the satellite positioning system with which communication becomes unstable (step S4), and then executes step S3.

[0041] As described above, the position acquisition system 100 and the position acquisition method described in this embodiment can be understood, for example, as follows.

[0042] The position acquisition system 100 of the first aspect comprises a first position detection unit (RTK positioning processing unit 70) that acquires the position of a moving mobile body, a second position detection unit (RTK positioning processing unit 122) that acquires the position of a target landing point set for the mobile body, a third position detection unit (RTK positioning processing unit 50) that acquires the position of an aircraft 1 landing at the target landing point, and a control unit that acquires the positional relationship between the mobile body, the target landing point, and the aircraft based on the detection results of the first position detection unit, the second position detection unit, and the third position detection unit, and the control unit acquires the relative position between the mobile body and the aircraft based on the position of the mobile body detected by the first position detection unit and the position of the aircraft 1 detected by the third position detection unit, and acquires the positional relationship between the mobile body and the target landing point as an offset position based on the position of the mobile body detected by the first position detection unit and the position of the target landing point detected by the second position detection unit.

[0043] According to this configuration, the system can be simplified by performing position acquisition using a position detection unit, and by using an offset position, the position between the aircraft 1 and the target landing point can be acquired with high accuracy.

[0044] As a second aspect, in the position acquisition system 100 according to the first aspect, the moving body is a ship.

[0045] With this configuration, the positions of the target landing point on the moving ship 5 and the aircraft 1 can be acquired with high accuracy.

[0046] As a third aspect, in the position acquisition system 100 according to the first or second aspect, each of the first position detection unit, the second position detection unit, and the third position detection unit includes an RTK-GPS.

[0047] According to this configuration, by using a highly accurate RTK-GPS, the positions of the aircraft 1 and the target landing point can be acquired with higher accuracy.

[0048] As a fourth aspect, in the position acquisition system 100 relating to the third aspect, the second position detection unit evaluates the communication status with a satellite positioning system including multiple satellites at the target landing point, and if there is a satellite with which communication is unstable, detects the position of the target landing point without using the positioning information of the unstable satellite.

[0049] According to this configuration, the position of the target landing point can be detected by excluding satellites with unstable communication, thereby suppressing a decrease in the accuracy of detecting the position at the target landing point.

[0050] As a fifth aspect, in the position acquisition system 100 relating to any one of the first to fourth aspects, the second position detection unit is provided in a portable position detection device 120, and the position detection device 120 has an operation unit (operation button 121), the second position detection unit that acquires position information based on operation of the operation unit, and a communication unit (data transmission device 123) that transmits the position information acquired by the second position detection unit to at least one of the mobile body and the aircraft 1.

[0051] According to this configuration, the position detection device 120 can be easily installed at the target landing point, and the position of the target landing point can be easily acquired.

[0052] A position acquisition method according to a sixth aspect is a position acquisition method executed by a position acquisition system that acquires the positional relationship between the position of a moving mobile body, the position of a target landing point set on the mobile body, and the position of an aircraft landing at the target landing point, and acquires the relative position between the mobile body and the aircraft based on the position of the mobile body and the position of the aircraft, and acquires the positional relationship between the mobile body and the target landing point as an offset position based on the position of the mobile body and the position of the target landing point.

[0053] According to this configuration, the system can be simplified by performing position acquisition of the relative position and the offset position, and by using the offset position, the position between the aircraft 1 and the target landing point can be acquired with high accuracy.

[0054] REFERENCE SIGNS LIST 1 Aircraft 5 Ship 20 Navigation device 30 Control unit 34 Guidance calculation unit 36 ​​Flight control unit 40 Data transmission device 50 RTK positioning processing unit 60 Navigation device 70 RTK positioning processing unit 80 Data transmission device 90 Operation display unit 100 Position acquisition system 120 Position detection device 121 Operation button 122 RTK positioning processing unit 123 Data transmission device

Claims

1. A position acquisition system comprising: a first position detection unit that acquires the position of a moving mobile body; a second position detection unit that acquires the position of a target landing point set on the mobile body; a third position detection unit that acquires the position of an aircraft landing at the target landing point; and a control unit that acquires the positional relationship between the mobile body, the target landing point, and the aircraft based on the detection results of the first position detection unit, the second position detection unit, and the third position detection unit, wherein the control unit acquires the relative position of the mobile body and the aircraft based on the position of the mobile body detected by the first position detection unit and the position of the aircraft detected by the third position detection unit, and acquires the positional relationship between the mobile body and the target landing point as an offset position based on the position of the mobile body detected by the first position detection unit and the position of the target landing point detected by the second position detection unit.

2. The position acquisition system according to claim 1, wherein the moving body is a ship.

3. The position acquisition system according to claim 1, wherein each of the first position detection unit, the second position detection unit, and the third position detection unit includes an RTK-GPS.

4. A position acquisition system as described in claim 3, wherein the second position detection unit evaluates the communication status with a satellite positioning system including a plurality of satellites at the target landing point, and if there is a satellite with which communication is unstable, detects the position of the target landing point without using the positioning information of the unstable satellite.

5. The position acquisition system of claim 1, wherein the second position detection unit is provided in a portable position detection device, and the position detection device has: an operation unit; the second position detection unit that acquires position information based on operation of the operation unit; and a communication unit that transmits the position information acquired by the second position detection unit to at least one of the mobile body and the aircraft.

6. A position acquisition method executed by a position acquisition system that acquires the positional relationship between the position of a moving mobile body, the position of a target landing point set for the mobile body, and the position of an aircraft landing at the target landing point, the method acquiring the relative position between the mobile body and the aircraft based on the position of the mobile body and the position of the aircraft, and acquiring the positional relationship between the mobile body and the target landing point as an offset position based on the position of the mobile body and the position of the target landing point.

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