Communication system

Abstract

A plurality of first communication instruments are mounted on one of a drone (2) and a landing port (3). A plurality of second communication instruments are mounted on the other of the drone (2) and the landing port (3). A drone-side control device (21) or a port-side control device (31) identifies the location of the drone (2) with respect to a target location associated with the landing port (3) on the basis of a signal compliant with the UWB wireless communication standard and transmitted from each of the plurality of first communication instruments to the plurality of second communication instruments.

Description

Communication system

[0001] The present disclosure relates to a communication system that performs wireless communication between a moving object and a stationary object.

[0002] Patent Document 1 discloses a system that controls a drone, which is an example of a moving object, to reach a target position based on image information acquired by a camera mounted on the drone.

[0003] Japanese Patent Application Laid-Open No. 2024-139777

[0004] There is a need to improve the positioning accuracy of a moving object with respect to a target position without relying on image information.

[0005] One exemplary aspect that can be provided by the present disclosure is a communication system, including: a plurality of first communication devices mounted on one of a moving object and a stationary object; a plurality of second communication devices mounted on the other of the moving object and the stationary object; and a control device that specifies the position of the moving object with respect to a target position associated with the stationary object based on first signals compliant with the UWB wireless communication standard transmitted from each of the plurality of first communication devices to the plurality of second communication devices.

[0006] When positioning a moving object with respect to a target position based on image information acquired by a camera, the influence of poor visibility due to bad weather or building groups cannot be avoided. However, according to the above configuration, the position of the moving object with respect to a target position associated with the stationary object can be specified based on communication compliant with the UWB wireless communication standard that uses radio waves and is less affected by multipath reflection. Therefore, the positioning accuracy of the moving object with respect to the target position can be improved without relying on image information.

[0007] This shows an example of the appearance of a drone and landing port included in a communication system according to one embodiment. The functional configuration of the drone and landing port in Figure 1 is illustrated. The communication flow between the first port-side communication device and the first drone-side communication device in Figure 2 is illustrated. An example of the drone positioning process flow is shown. Another example of the drone positioning process flow is shown. Another example of the drone positioning process flow is shown. Another example of the drone positioning process flow is shown. Another example of the drone positioning process flow is shown. Another example of the drone positioning process flow is shown. Another example of the drone positioning process flow is shown. Another example of the drone positioning process flow is shown. Another example of the drone positioning process flow is shown. A diagram illustrating another example of the drone positioning process. A diagram illustrating another example of the drone positioning process.

[0008] The embodiments will be described in detail below with reference to the attached drawings. In the drawings used in the following description, the scale has been appropriately changed to make each element recognizable.

[0009] Figure 1 illustrates the external appearance of a drone 2 and a landing port 3 included in a communication system 1 according to one embodiment. The communication system 1 is configured to land the drone 2 at a target position at the landing port 3 using communication compliant with the UWB (Ultra-Wide Band) wireless communication standard. The drone 2 is an example of an aerial body and an example of a moving body. The landing port 3 is an example of a stationary body.

[0010] An example of a UWB wireless communication standard is channel number 9 in IEEE 802.15.4a (center frequency: 7987.2 MHz, frequency bandwidth: 499.2 MHz).

[0011] As illustrated in Figure 2, the drone 2 is equipped with multiple drone-side communication devices. In this example, the drone 2 is equipped with a first drone-side communication device D1, a second drone-side communication device D2, a third drone-side communication device D3, and a fourth drone-side communication device D4.

[0012] On the other hand, landing port 3 is equipped with multiple port-side communicators. In this example, landing port 3 is equipped with a first port-side communicator P1, a second port-side communicator P2, a third port-side communicator P3, and a fourth port-side communicator P4.

[0013] Each of the multiple drone-side communicators and multiple port-side communicators has a well-known configuration that enables bidirectional communication in accordance with the aforementioned UWB wireless communication standard. In other words, each of the multiple drone-side communicators and multiple port-side communicators has radio wave transmission and reception functions.

[0014] Drone 2 is equipped with a drone-side control device 21. The drone-side control device 21 is configured to control the radio wave transmission operation of each of the multiple drone-side communication devices. The drone-side control device 21 is configured to acquire information superimposed on the radio waves received by each of the multiple drone-side communication devices.

[0015] The landing port 3 is equipped with a port-side control device 31. The port-side control device 31 is configured to control the radio wave transmission operation of each of the multiple port-side communication devices. The port-side control device 31 is configured to acquire information superimposed on the radio waves received by each of the multiple port-side communication devices.

[0016] Referring to Figure 3, the positioning process performed between the first port-side communication device P1 and the first drone-side communication device D1 will be explained.

[0017] The port-side control device 31 causes the first port-side communicator P1 to transmit a first start signal p1 at time t1. The first start signal p1 is received by the first drone-side communicator D1 at time t2.

[0018] The drone-side control device 21, in response to the first start signal p1, causes the first drone-side communicator D1 to transmit a first response signal r1 at time t3. The first response signal r1 is received by the first port-side communicator P1 at time t4.

[0019] The port-side control device 31, in response to the first response signal r1, causes the first port-side communicator P1 to transmit a first completion signal f1 at time t5. The first completion signal f1 is configured to include information that identifies times t1, t4, and t5. The first completion signal f1 is received by the first drone-side communicator D1 at time t6.

[0020] The drone-side control device 21 holds information that identifies time points t2, t3, and t6. Adding the information that identifies time points t1, t4, and t5 provided by the first completion signal f1, the drone-side control device 21 calculates the following equation to obtain the distance d11 between the first port-side communicator P1 and the first drone-side communicator D1. The symbol c is the speed of light. d11 = c[(t4 - t1) - (t3 - t2) + (t6 - t3) - (t5 - t4)] / 4

[0021] Similarly, the drone-side control device 21 obtains the distance d21 between the second port-side communication device P2 and the first drone-side communication device D1, the distance d31 between the third port-side communication device P3 and the first drone-side communication device D1, and the distance d41 between the fourth port-side communication device P4 and the first drone-side communication device D1. Based on the distances between the first drone-side communication device D1 and each of the four port-side communication devices, the three-dimensional coordinates of the first drone-side communication device D1 can be determined by processing such as solving a system of three linear equations known in positioning technology.

[0022] The drone-side control device 21 controls the flight of the drone 2 so that the three-dimensional coordinates of the identified first drone-side communication device D1 are brought closer to the three-dimensional coordinates corresponding to the target position of the landing port 3. This allows the drone 2 to land at the landing port 3.

[0023] In this embodiment, the distances of the second drone-side communication device D2, the third drone-side communication device D3, and the fourth drone-side communication device D4 to each of the four port-side communication devices are obtained in the same manner. Therefore, the three-dimensional coordinates of the four drone-side communication devices are obtained based on a total of 16 pieces of distance information. Furthermore, once the positions of the four drone-side communication devices are determined, the attitude of the drone 2 (which direction each specific position is facing) can also be determined.

[0024] Referring to Figure 4, we will explain an example of a specific wireless communication flow between multiple port-side communicators and multiple drone-side communicators. For simplicity, we will describe the case where the distance d11 between the first port-side communicator P1 and the first drone-side communicator D1, the distance d12 between the first port-side communicator P1 and the second drone-side communicator D2, the distance d21 between the second port-side communicator P2 and the first drone-side communicator D1, and the distance d22 between the second port-side communicator P2 and the second drone-side communicator D2 are obtained.

[0025] First, the port-side control device 31 causes the first port-side communicator P1 to transmit a first start signal p1 at time t1. The first start signal p1 is received by the first drone-side communicator D1 and the second drone-side communicator D2 at times t2 and t3, respectively.

[0026] Next, the drone-side control device 21 causes the first drone-side communication device D1 to transmit the first response signal r1 at time t4. The first response signal r1 is received by the first port-side communication device P1 at time t5.

[0027] Similarly, the drone-side control device 21 causes the second drone-side communication device D2 to transmit a second response signal r2 at time t6. The second response signal r2 is received by the first port-side communication device P1 at time t7.

[0028] Next, the port-side control device 31 causes the first port-side communicator P1 to transmit a first completion signal f1 at time t8. The first completion signal f1 is received by the first drone-side communicator D1 and the second drone-side communicator D2 at time t9 and t10, respectively. The first completion signal f1 is configured to include information that identifies time points t1, t5, t7, and t8.

[0029] Based on the information that identifies the time points t2, t4, and t9 and the information contained in the first completion signal f1, the drone-side control device 21 acquires the distance d11 between the first port-side communication device P1 and the first drone-side communication device D1 in the same manner as described with reference to Figure 3.

[0030] Similarly, the drone-side control device 21 obtains the distance d12 between the first port-side communicator P1 and the second drone-side communicator D2 based on information that identifies time points t3, t6, and t10 and information contained in the first completion signal f1.

[0031] Next, the port-side control device 31 causes the second port-side communication device P2 to transmit a second start signal p2 at time t11. The second start signal p2 is received by the first drone-side communication device D1 and the second drone-side communication device D2 at times t12 and t13, respectively.

[0032] Next, the drone-side control device 21 causes the first drone-side communicator D1 to transmit the first response signal r1 at time t14. The first response signal r1 is received by the second port-side communicator P2 at time t15. The first response signal r1 is also received by the first port-side communicator P1.

[0033] Similarly, the drone-side control device 21 causes the second drone-side communication device D2 to transmit the second response signal r2 at time t16. The second response signal r2 is received by the second port-side communication device P2 at time t17.

[0034] Next, the port-side control device 31 causes the second port-side communicator P2 to transmit a second completion signal f2 at time t18. The second completion signal f2 is received by the first drone-side communicator D1 and the second drone-side communicator D2 at time t19 and t20, respectively. The second completion signal f2 is configured to include information that identifies time points t11, t15, t17, and t18.

[0035] The drone-side control device 21 acquires the distance d21 between the second port-side communicator P2 and the first drone-side communicator D1 in the same manner as described with reference to Figure 3, based on the information that identifies the time points t12, t14, and t19 and the information contained in the second completion signal f2.

[0036] Similarly, the drone-side control device 21 obtains the distance d22 between the second port-side communicator P2 and the second drone-side communicator D2 based on the information that identifies the times t13, t16, and t20 and the information contained in the second completion signal f2.

[0037] At time t5 (t15), the first response signal r1 is also received by the second port-side communicator P2, and at time t7 (t17), the second response signal r2 is also received by the first port-side communicator P1. The port-side control device 31 can enable the reception of the response signal at one port-side communicator and disable the reception of the response signal at the other port-side communicator by referring to the reception time.

[0038] Alternatively, reception of the response signal at one port receiver can be enabled by switching control to enable signal reception at only one of the first port-side communicator P1 and the second port-side communicator P2, depending on the elapsed time from the time t1 when the first start signal p1 is transmitted (t11 when the second start signal p2 is transmitted).

[0039] Each response signal may include identification information that identifies the transmitting drone-side communication device. In this case, the port-side control device 31 can enable reception of the response signal on one port-side communication device and disable reception of the response signal on the other port-side communication device by referring to the identification information.

[0040] In other words, in this example, a start signal transmitted from one of the four port-side communicators is received by the four drone-side communicators, and a response signal is transmitted from each of the four drone-side communicators to the port-side communicator, thereby obtaining the distance between the port-side communicator and each of the four drone-side communicators. The same process is repeated for the remaining three port-side communicators, obtaining a total of 16 pieces of distance information, and identifying the position of each of the four drone-side communicators. In this example, the port-side communicator is an example of the first communicator, and the drone-side communicator is an example of the second communicator. The start signal is an example of the first signal, and the response signal is an example of the second signal.

[0041] In addition to the four distance information points obtained in the processing example explained with reference to Figure 4, the remaining 12 distance information points that can be obtained in the same manner are as follows. Distance d13 between the first port side communicator P1 and the third drone side communicator D3 Distance d14 between the first port side communicator P1 and the fourth drone side communicator D4 Distance d23 between the second port side communicator P2 and the third drone side communicator D3 Distance d24 between the second port side communicator P2 and the fourth drone side communicator D4 Distance d31 between the third port side communicator P3 and the first drone side communicator D1 Distance d32 between the third port side communicator P3 and the second drone side communicator D2 Distance d33 between the third port side communicator P3 and the third drone side communicator D4 Distance d34 between the fourth port side communicator P4 and the first drone side communicator D1 Distance d41 between the fourth port side communicator P4 and the second drone side communicator D2 Distance d42 between the fourth port side communicator P4 and the third drone side communicator D3 The distance between the fourth port-side communicator P4 and the fourth drone-side communicator D4 is d44.

[0042] When positioning a drone relative to a target location based on image information acquired by a camera, the effects of poor visibility due to bad weather or buildings are unavoidable. However, according to the configuration of this embodiment, the position of the drone 2 relative to the target location associated with the landing port 3 can be determined based on communication compliant with the UWB wireless communication standard, which uses radio waves and is less susceptible to multipath reflection. Therefore, the positioning accuracy of the drone 2 relative to the target location can be improved without relying on image information.

[0043] In addition, in this example, the positional relationship between each of the multiple drone-side communicators and each of the multiple port-side communicators is determined based on the bidirectional communication between the port-side communicator and the drone-side communicator, so that the position of the drone 2 relative to the landing port 3 can be determined more precisely.

[0044] In this processing example, the process of transmitting the first start signal p1 from the first port-side communication device P1 and the process of transmitting the second start signal p2 from the second port-side communication device P2 can be executed independently as long as interference between the first start signal p1 and the second start signal p2 can be avoided. In other words, the transmission process of the start signal can be separated from under the control of the port-side control device 31. In this case, for the process of transmitting a plurality of start signals from a plurality of port-side communication devices, the process related to cooperation can be made unnecessary, so that the complication of the algorithm design of the port-side control device 31 and the increase in the processing load can be suppressed.

[0045] While referring to FIG. 5, a separate example of the specific flow of wireless communication performed between a plurality of port-side communication devices and a plurality of drone-side communication devices will be described. The same reference numerals are assigned to the elements common to FIG. 4, and repeated descriptions are omitted.

[0046] First, the port-side control device 31 causes the first port-side communication device P1 to transmit the first start signal p1 at time t1. The first start signal p1 is received by the first drone-side communication device D1 and the second drone-side communication device D2 at times t2 and t3, respectively.

[0047] [[ID=;9]] Subsequently, the port-side control device 31 causes the second port-side communication device P2 to transmit the second start signal p2 at time t4. The second start signal p2 is received by the first drone-side communication device D1 and the second drone-side communication device D2 at times t5 and t6, respectively.

[0048] The drone-side control device 21 can identify from which port-side communication device the received start signal was transmitted by referring to the reception time or the reception order. Note that the start signal may be identified by including identification information for identifying the source port-side communication device in each start signal and causing the drone-side control device 21 to refer to the identification information.

[0049] Next, the drone-side control device 21 causes the first drone-side communication device D1 to transmit the first response signal r1 at time t7. The first response signal r1 is received by the first port-side communication device P1 and the second port-side communication device P2 at times t8 and t9, respectively.

[0050] Next, the drone-side control device 21 causes the second drone-side communication device D2 to transmit a second response signal r2 at time t10. The second response signal r2 is received by the first port-side communication device P1 and the second port-side communication device P2 at times t11 and t12, respectively.

[0051] The port-side control device 31 can identify which drone-side communication device transmitted the received response signal by referring to the reception time or reception order. Alternatively, each response signal may include identification information that identifies the source drone-side communication device, and the source of the start signal may be identified by having the port-side control device 31 refer to this identification information.

[0052] Next, the port-side control device 31 causes the first port-side communicator P1 to transmit a first completion signal f1 at time t13. The first completion signal f1 is received by the first drone-side communicator D1 and the second drone-side communicator D2 at time t14 and t15, respectively. The first completion signal f1 is configured to include information that identifies time points t1, t8, t11, and t13.

[0053] Next, the port-side control device 31 causes the second port-side communicator P2 to transmit a second completion signal f2 at time t16. The second completion signal f2 is received by the first drone-side communicator D1 and the second drone-side communicator D2 at times t17 and t18, respectively. The second completion signal f2 is configured to include information that identifies times t4, t9, t12, and t16.

[0054] The drone-side control device 21 can identify which port-side communicator transmitted the received completion signal by referring to the reception time or reception order. Alternatively, each start signal may include identification information that identifies the source port-side communicator, and the source of the start signal may be identified by having the drone-side control device 21 refer to this identification information.

[0055] Based on the information that identifies the time points t2, t7, and t14 and the information contained in the first completion signal f1, the drone-side control device 21 acquires the distance d11 between the first port-side communication device P1 and the first drone-side communication device D1 in the same manner as described with reference to Figure 3.

[0056] Similarly, the drone-side control device 21 obtains the distance d21 between the second port-side communicator P2 and the first drone-side communicator D1 based on the information that identifies the time points t5, t7, and t17 and the information contained in the second completion signal f2.

[0057] On the other hand, the drone-side control device 21 acquires the distance d12 between the first port-side communicator P1 and the second drone-side communicator D2 in the same manner as described with reference to Figure 3, based on the information that identifies the time points t3, t10, and t15 and the information contained in the first completion signal f1.

[0058] Similarly, the drone-side control device 21 obtains the distance d22 between the second port-side communicator P2 and the second drone-side communicator D2 based on the information that identifies the times t6, t10, and t18 and the information contained in the second completion signal f2.

[0059] In other words, in this example, after N start signals are transmitted from the four port-side communicators, M response signals are transmitted from the four drone-side communicators, thereby obtaining the distance between each of the N port-side communicators and each of the M drone-side communicators. Here, N is an integer greater than or equal to 2, and M is an integer less than or equal to N. In the example shown in Figure 5, N = M = 2.

[0060] For example, after start signals are sequentially transmitted from each of the four port-side transmitters and received by each of the four drone-side communicators, response signals are sequentially transmitted from each of the four drone-side communicators to the four port-side communicators, thereby obtaining the distance between each of the four port-side communicators and each of the four drone-side communicators. In this case, N = M = 4.

[0061] This configuration requires coordinated control for transmitting the start signal, but it reduces the amount of communication traffic needed to acquire the desired number of distance information devices. This effect becomes more pronounced as the number of N increases. Therefore, it can suppress the increase in communication traffic and power consumption that accompanies an increase in the number of communication devices.

[0062] Furthermore, in the processing example explained with reference to Figures 4 and 5, in order to satisfy the condition that M is less than N, a configuration may be adopted in which the total number of drone-side communication devices is less than the total number of port-side communication devices. In this case, the increase in the weight and power consumption of drone 2 can be suppressed.

[0063] As an example, consider the case where there are 3 port-side communicators and 2 drone-side communicators. In this case, in the processing example explained with reference to Figure 4, the distances d13, d14, d23, d24, d33, d34, d41, d42, d43, and d44 related to the fourth port-side communicator P4, the third drone-side communicator D3, and the fourth drone-side communicator D4 are excluded from acquisition.

[0064] In the example process described with reference to Figure 5, distance information is acquired in the order illustrated in Figure 6. That is, after the start signals transmitted sequentially from each of the three port-side transmitters are received by the two drone-side communicators, response signals are sequentially transmitted from each of the two drone-side communicators to the three port-side communicators.

[0065] In the positioning process example described with reference to Figures 3 to 6, a start signal is transmitted from multiple port-side communicators mounted on the landing port 3. However, the start signal may also be transmitted from multiple drone-side communicators mounted on the drone 2.

[0066] Referring to Figure 7, another example of the specific flow of such wireless communication between multiple port-side communicators and multiple drone-side communicators will be described. Elements common to Figure 4 will be given the same reference numerals, and redundant explanations will be omitted.

[0067] First, the drone-side control device 21 causes the first drone-side communicator D1 to transmit a first start signal p1 at time t1. The first start signal p1 is received by the first port-side communicator P1 and the second port-side communicator P2 at times t2 and t3, respectively.

[0068] Next, the port-side control device 31 causes the first port-side communication device P1 to transmit the first response signal r1 at time t4. The first response signal r1 is received by the first drone-side communication device D1 at time t5.

[0069] Similarly, the port-side control device 31 causes the second port-side communicator P2 to transmit the second response signal r2 at time t6. The second response signal r2 is received by the first drone-side communicator D1 at time t7.

[0070] Next, the drone-side control device 21 causes the first drone-side communicator D1 to transmit a first completion signal f1 at time t8. The first completion signal f1 is received by the first port-side communicator P1 and the second port-side communicator P2 at times t9 and t10, respectively. The first completion signal f1 is configured to include information that identifies times t1, t5, t7, and t8.

[0071] Based on the information that identifies the time points t2, t4, and t9 and the information contained in the first completion signal f1, the port-side control device 31 acquires the distance d11 between the first port-side communication device P1 and the first drone-side communication device D1 in the same manner as described with reference to Figure 3.

[0072] Similarly, the port-side control device 31 obtains the distance d21 between the second port-side communicator P2 and the first drone-side communicator D1 based on information that identifies time points t3, t6, and t10 and information contained in the first completion signal f1.

[0073] The first response signal r1 and the second response signal r2 are also received by the second drone-side communicator D2 at time t5 and time t7, respectively. The drone-side control device 21 can enable the reception of the response signals at the first drone-side communicator D1 and disable the reception of the response signals at the second drone-side communicator D2 by referring to the reception time.

[0074] Alternatively, the reception of the response signal by the second drone-side communicator D2 can be disabled by switching only the first drone-side communicator D1 to receive signals according to the elapsed time from the time t1 when the first start signal p1 was transmitted.

[0075] Each response signal may include identification information that identifies the first drone-side communicator D1. In this case, the drone-side control device 21 can disable the reception of the response signal at the second drone-side communicator D2 by referring to the identification information.

[0076] Next, the drone-side control device 21 causes the second drone-side communication device D2 to transmit a second start signal p2 at time t11. The second start signal p2 is received by the first port-side communication device P1 and the second port-side communication device P2 at times t12 and t13, respectively.

[0077] Next, the port-side control device 31 causes the first port-side communication device P1 to transmit the first response signal r1 at time t14. The first response signal r1 is received by the second drone-side communication device D2 at time t15.

[0078] Similarly, the port-side control device 31 causes the second port-side communication device P2 to transmit the second response signal r2 at time t16. The second response signal r2 is received by the second drone-side communication device D2 at time t17.

[0079] Next, the drone-side control device 21 causes the second drone-side communication device D2 to transmit a second completion signal f2 at time t18. The second completion signal f2 is received by the first port-side communication device P1 and the second port-side communication device P2 at time t19 and t20, respectively. The second completion signal f2 is configured to include information that identifies time points t11, t15, t17, and t18.

[0080] Based on the information that identifies the time points t12, t14, and t19 and the information contained in the second completion signal f2, the port-side control device 31 acquires the distance d12 between the first port-side communicator P1 and the second drone-side communicator D2 in the same manner as described with reference to Figure 3.

[0081] Similarly, the port-side control device 31 obtains the distance d22 between the second port-side communicator P2 and the second drone-side communicator D2 based on the information that identifies the times t13, t16, and t20 and the information contained in the second completion signal f2.

[0082] The first response signal r1 and the second response signal r2 are also received by the first drone-side communicator D1 at time t15 and time t17, respectively. The drone-side control device 21 can enable the reception of the response signals at the second drone-side communicator D2 and disable the reception of the response signals at the first drone-side communicator D1 by referring to the reception time.

[0083] Alternatively, the reception of the response signal at the first drone-side communicator D1 can be disabled by switching only the second drone-side communicator D2 to receive signals according to the elapsed time from the time t11 when the second start signal p2 was transmitted.

[0084] Each response signal may include identification information that identifies the second drone-side communication device D2. In this case, the drone-side control device 21 can disable the reception of the response signal at the first drone-side communication device D1 by referring to the identification information.

[0085] In other words, in this example, a start signal transmitted from one of the four drone-side communicators is received by the four port-side communicators, and a response signal is transmitted from each of the four port-side communicators to the drone-side communicator, thereby obtaining the distance between the drone-side communicator and each of the four port-side communicators. The same process is repeated for the remaining three drone-side communicators, thereby obtaining a total of 16 pieces of distance information. In this example, the drone-side communicator is an example of the first communicator, and the port-side communicator is an example of the second communicator. The start signal is an example of the first signal, and the response signal is an example of the second signal. Since the process of obtaining distance information can be performed by the port-side control device 31, the computational load and power consumption of the drone-side control device 21 can be suppressed.

[0086] Since the acquired distance information is located at the landing port, the acquired distance information is transmitted from the landing port 3 to the drone 2 in order for the drone 2 to determine its own position. For example, the transmission of distance information is performed using communication compliant with the UWB wireless communication standard.

[0087] However, communication compliant with the UWB wireless communication standard has the characteristic that the power consumption burden is greater on the receiving side than on the transmitting side. As an alternative to avoid this problem, distance information can be transmitted using signals that do not comply with the UWB wireless communication standard.

[0088] Specifically, as illustrated in Figure 2, the drone 2 and the landing port 3 may be equipped with auxiliary communication devices 22 and 32, respectively. The auxiliary communication devices 22 and 32 are configured to send and receive an auxiliary signal ax via short-range wireless communication that does not conform to the UWB wireless communication standard. Examples of such short-range wireless communication include Bluetooth®, Bluetooth Low Energy®, ZigBee®, and Wi-Fi®. The auxiliary signal ax is an example of a third signal.

[0089] In this example, although the amount of communication traffic increases as drone 2 ultimately determines its own position, it has the advantage that drone 2 can determine the timing of when to start the processing. For example, it may be possible to control the process so that it starts when environmental factors that hinder positioning processing are eliminated.

[0090] In this example, the process of transmitting the first start signal p1 from the first drone-side communicator D1 and the process of transmitting the second start signal p2 from the second drone-side communicator D2 can be executed independently, provided that interference between the first start signal p1 and the second start signal p2 can be avoided. In other words, the start signal transmission process can be separated from the control of the drone-side control device 21. In this case, the process of coordinating multiple start signals transmitted from multiple drone-side communicators can be made unnecessary, thereby suppressing the complexity of the algorithm design and the increase in processing load of the drone-side control device 21.

[0091] Referring to Figure 8, we will now describe another example of the specific flow of wireless communication between multiple port-side communicators and multiple drone-side communicators. Elements common to Figure 5 are given the same reference numerals, and redundant explanations are omitted.

[0092] First, the drone-side control device 21 causes the first drone-side communicator D1 to transmit a first start signal p1 at time t1. The first start signal p1 is received by the first port-side communicator P1 and the second port-side communicator P2 at times t2 and t3, respectively.

[0093] Next, the drone-side control device 21 causes the second drone-side communication device D2 to transmit a second start signal p2 at time t4. The second start signal p2 is received by the first port-side communication device P1 and the second port-side communication device P2 at times t5 and t6, respectively.

[0094] The port-side control device 31 can identify which drone-side communicator transmitted the received start signal by referring to the reception time or reception order. Alternatively, each response signal may include identification information that identifies the source drone-side communicator, and the port-side control device 31 may refer to this identification information to identify the source of the start signal.

[0095] Next, the port-side control device 31 causes the first port-side communicator P1 to transmit the first response signal r1 at time t7. The first response signal r1 is received by the first drone-side communicator D1 and the second drone-side communicator D2 at time t8 and t9, respectively.

[0096] Next, the port-side control device 31 causes the second port-side communication device P2 to transmit the second response signal r2 at time t10. The second response signal r2 is received by the first drone-side communication device D1 and the second drone-side communication device D2 at times t11 and t12, respectively.

[0097] The drone-side control device 21 can identify which port-side communicator transmitted the received response signal by referring to the reception time or reception order. Alternatively, each start signal may include identification information that identifies the source port-side communicator, and the source of the start signal may be identified by having the drone-side control device 21 refer to this identification information.

[0098] Next, the drone-side control device 21 causes the first drone-side communicator D1 to transmit a first completion signal f1 at time t13. The first completion signal f1 is received by the first port-side communicator P1 and the second port-side communicator P2 at times t14 and t15, respectively. The first completion signal f1 is configured to include information that identifies times t1, t8, t11, and t13.

[0099] Next, the drone-side control device 21 causes the second drone-side communication device D2 to transmit a second completion signal f2 at time t16. The second completion signal f2 is received by the first port-side communication device P1 and the second port-side communication device P2 at times t17 and t18, respectively. The second completion signal f2 is configured to include information that identifies times t4, t9, t12, and t16.

[0100] The port-side control device 31 can identify which drone-side communicator transmitted the received completion signal by referring to the reception time or reception order. Alternatively, each response signal may include identification information that identifies the source drone-side communicator, and the source of the start signal may be identified by having the port-side control device 31 refer to this identification information.

[0101] Based on the information that identifies time points t2, t7, and t14 and the information contained in the first completion signal f1, the port-side control device 31 acquires the distance d11 between the first port-side communication device P1 and the first drone-side communication device D1 in the same manner as described with reference to Figure 3.

[0102] Similarly, the port-side control device 31 obtains the distance d12 between the first port-side communicator P1 and the second drone-side communicator D2 based on the information that identifies the times t5, t7, and t17 and the information contained in the second completion signal f2.

[0103] On the other hand, the port-side control device 31 acquires the distance d21 between the second port-side communication device P2 and the first drone-side communication device D1 in the same manner as described with reference to Figure 3, based on the information that identifies the time points t3, t10, and t15 and the information contained in the first completion signal f1.

[0104] Similarly, the port-side control device 31 obtains the distance d22 between the second port-side communicator P2 and the second drone-side communicator D2 based on the information that identifies the times t6, t10, and t18 and the information contained in the second completion signal f2.

[0105] In other words, in this example, after N start signals are transmitted from the four drone-side communicators, M response signals are transmitted from the four port-side communicators, thereby obtaining the distance between each of the N drone-side communicators and each of the M port-side communicators. Here, N is an integer greater than or equal to 2, and M is an integer less than or equal to N. In the example shown in Figure 7, N = M = 2.

[0106] For example, after start signals are sequentially transmitted from each of the four drone-side transmitters and received by each of the four port-side communicators, response signals are sequentially transmitted from each of the four port-side communicators to the four drone-side communicators, thereby obtaining the distance between each of the four port-side communicators and each of the four drone-side communicators. In this case, N = M = 4.

[0107] This configuration requires coordinated control for transmitting the start signal, but it reduces the amount of communication traffic needed to acquire the desired number of distance information devices. This effect becomes more pronounced as the number of N increases. Therefore, it can suppress the increase in communication traffic and power consumption that accompanies an increase in the number of communication devices.

[0108] In the processing example described with reference to Figures 7 and 8, a configuration may be adopted in which the total number of port-side communicators is less than the total number of drone-side communicators in order to satisfy the condition that M is less than N.

[0109] As an example, consider the case where there are 3 drone-side communication devices and 2 port-side communication devices. In this case, in the processing example explained with reference to Figure 7, the distances d14, d24, d31, d32, d33, d34, d41, d42, d43, and d44 related to the fourth drone-side communication device D4, the third port-side communication device P3, and the fourth port-side communication device P4 are excluded from acquisition.

[0110] In the example process described with reference to Figure 8, distance information is acquired in the order illustrated in Figure 9. That is, after the start signals transmitted sequentially from each of the three drone-side transmitters are received by the two port-side communicators, response signals are sequentially transmitted from each of the two port-side communicators to the three drone-side communicators.

[0111] In each of the embodiments described so far, the position of the drone 2 relative to the target location is determined based on bidirectional communication between multiple drone-side communicators and multiple port-side communicators. However, the position of the drone 2 relative to the target location may also be determined based on unidirectional communication between multiple drone-side communicators or multiple port-side communicators.

[0112] Referring to Figure 10, we will now describe an example of the specific flow of such wireless communication between multiple port-side communicators and multiple drone-side communicators. Elements common to Figure 4 are given the same reference numerals, and redundant explanations are omitted.

[0113] First, the port-side control device 31 causes the first port-side communicator P1 to transmit a first start signal p1 at time t1. The first start signal p1 is configured to include information that identifies time t1. The first start signal p1 is received by the first drone-side communicator D1 and the second drone-side communicator D2 at times t2 and t3, respectively.

[0114] Next, the port-side control device 31 causes the second port-side communication device P2 to transmit a second start signal p2 at time t4. The second start signal p2 is configured to include information that identifies time t4. The second start signal p2 is received by the first drone-side communication device D1 and the second drone-side communication device D2 at times t5 and t6, respectively.

[0115] The drone-side control device 21 can identify which port-side communicator transmitted the received start signal by referring to the reception time or reception order. Alternatively, each start signal may include identification information that identifies the transmitting port-side communicator, and the source of the start signal may be identified by having the drone-side control device 21 refer to this identification information.

[0116] The drone-side control device 21 acquires the time T12 (time from time t1 to time t2) from when the first start signal p1 is transmitted from the first port-side communication device P1 until it is received by the first drone-side communication device D1.

[0117] Similarly, the time T13 (time from time t1 to time t3) from when the first start signal p1 is transmitted from the first port-side communicator P1 to when it is received by the second drone-side communicator D2, the time T12 (time from time t4 to time t5) from when the second start signal p2 is transmitted from the second port-side communicator P2 to when it is received by the first drone-side communicator D1, the time T45 (time from time t4 to time t5) from when the second start signal p2 is transmitted from the second port-side communicator P2 to when it is received by the second drone-side communicator D2, and the time T46 (time from time t4 to time t6) from when the second start signal p2 is transmitted from the second port-side communicator P2 to when it is received by the second drone-side communicator D2 are obtained.

[0118] Although this time information does not allow for obtaining information about the distance between specific communication devices, it does allow for obtaining information about the difference between the distance between one pair of communication devices and the distance between another pair of communication devices, based on the time difference. The drone-side control device 21 obtains four sets of time difference information (T12-T13), (T12-T45), (T13-T46), and (T45-T46) based on the four sets of time information. As a result, information about the distance difference for the four pairs of communication devices can be obtained, and the three-dimensional coordinates of the drone 2 can be determined by solving a system of three equations known in positioning technology.

[0119] The drone control device 21 performs flight control to bring the identified three-dimensional coordinates of the drone 2 closer to the three-dimensional coordinates corresponding to the target position of the landing port 3. This allows the drone 2 to land at the landing port 3.

[0120] According to the configuration in this example, although the accuracy is inferior to positioning based on bidirectional communication, the amount of communication traffic between the drone and the landing port 3, and the processing load on the drone-side control device 21 can be reduced.

[0121] Furthermore, in the processing example explained with reference to Figure 10, a configuration may be adopted in which the total number of drone-side communication devices is less than the total number of port-side communication devices. As an example, consider the case where the number of port-side communication devices is 3 and the number of drone-side communication devices is 2.

[0122] In this case, as illustrated in Figure 11, the time T78 (time from time t7 to time t8) from when the third start signal p3 is transmitted from the third port side communicator P3 until it is received by the first drone side communicator D1, and the time T79 (time from time t7 to time t9) from when the third start signal p3 is transmitted from the third port side communicator P3 until it is received by the second drone side communicator D2 are acquired. Therefore, the drone side control device 21 acquires five more sets of time difference information, including (T78-T79), (T12-T78), (T45-T78), (T13-T79), and (T46-T79), and identifies the three-dimensional coordinates of the drone 2 based on a total of nine sets of time difference information.

[0123] Even when the positioning of drone 2 is performed based on one-way communication, the start signal may be transmitted from multiple drone-side communicators mounted on drone 2. Referring to Figure 12, another example of the specific flow of such wireless communication between multiple port-side communicators and multiple drone-side communicators will be described. Elements common to Figure 10 are given the same reference numerals, and repeated explanations are omitted.

[0124] First, the drone-side control device 21 causes the first drone-side communication device D1 to transmit a first start signal p1 at time t1. The first start signal p1 is configured to include information that identifies time t1. The first start signal p1 is received by the first port-side communication device P1 and the second port-side communication device P2 at times t2 and t3, respectively.

[0125] Next, the drone-side control device 21 causes the second drone-side communication device D2 to transmit a second start signal p2 at time t4. The second start signal p2 is configured to include information that identifies time t4. The second start signal p2 is received by the first port-side communication device P1 and the second port-side communication device P2 at times t5 and t6, respectively.

[0126] The port-side control device 31 can identify which drone-side communicator transmitted the received start signal by referring to the reception time or reception order. Alternatively, each start signal may include identification information that identifies the source drone-side communicator, and the port-side control device 31 may refer to this identification information to identify the source of the start signal.

[0127] The port-side control device 31 acquires the time T12 (time from time t1 to time t2) from when the first start signal p1 is transmitted from the first drone-side communication device D1 until it is received by the first port-side communication device P1.

[0128] Similarly, the time T13 (time from time t1 to time t3) from when the first start signal p1 is transmitted from the first drone-side communicator D1 until it is received by the second port-side communicator P2, the time T12 (time from time t4 to time t5) from when the second start signal p2 is transmitted from the second drone-side communicator D2 until it is received by the first port-side communicator P1, and the time T46 (time from time t4 to time t6) from when the second start signal p2 is transmitted from the second drone-side communicator D2 until it is received by the second port-side communicator P2 are obtained.

[0129] The port-side control device 31 acquires four sets of time difference information (T12-T13), (T12-T45), (T13-T46), and (T45-T46) based on four time information. As a result, it can acquire distance difference information for the four sets of communication devices.

[0130] Similar to the processing example described with reference to Figure 7, the acquired distance difference information is transmitted from the landing port 3 to the drone 2. Transmission may be performed using communication compliant with the UWB wireless communication standard, or it may be transmitted from the auxiliary communication device 32 of the landing port 3 to the auxiliary communication device 22 of the drone 2 using the auxiliary signal ax. The drone-side control device 21 performs processing to determine the position of the drone 2 based on the received distance difference information.

[0131] In this processing example, compared to the processing example explained with reference to Figure 10, the amount of communication traffic increases in order for the drone 2 to ultimately determine its own position, but it has the advantage that the timing of when the processing starts can be determined by the drone 2. For example, it may be possible to control the process so that it starts when environmental factors that hinder the positioning process are eliminated.

[0132] As illustrated in Figure 13, even in this case, a configuration can be adopted in which the total number of port-side communication devices is less than the total number of drone-side communication devices.

[0133] As illustrated in Figure 1, the communication system 1 can be configured to cooperate with GPS (Global Positioning System) 4. The drone-side control device 21 can acquire its own position information PS via GPS 4.

[0134] On the other hand, as illustrated in Figure 14, a first region A1 having a specific range based on the target position associated with the landing port 3 may be set. In this case, the drone-side control device 21 may be configured to perform flight control based on position information PS provided via GPS 4 until it enters the first region A1.

[0135] Specifically, the drone-side control device 21 compares the coordinates corresponding to the first region A1, which are pre-stored in a storage device (not shown), with the coordinates corresponding to the position information PS, to determine whether the drone 2 has entered the first region A1. When the drone-side control device 21 determines that the drone 2 has entered the first region A1, it may be configured to start positioning processing using communication compliant with the UWB wireless communication standard. The processing to be executed may be any of the processing examples described with reference to Figures 4 to 13.

[0136] If the position information PS acquired by the drone 2 can be provided to the landing port 3 using, for example, the auxiliary signal ax described above, the decision to switch from positioning using GPS 4 to positioning using communication compliant with the UWB wireless communication standard may be made by the port-side control device 31.

[0137] With this configuration, power consumption associated with positioning processing using communication compliant with the UWB wireless communication standard can be kept to a minimum.

[0138] As illustrated in Figure 14, a second region A2 may be set within the first region A1. The second region A2 is narrower than the first region A1. In this case, the drone-side control device 21 or the port-side control device 31 may be configured to start positioning processing based on one-way communication as described with reference to Figures 10 to 13 when it is determined that the drone 2 has entered the first region A1, and to start positioning processing based on two-way communication as described with reference to Figures 4 to 9 when it is determined that the drone 2 has entered the second region A2.

[0139] With this configuration, processing based on bidirectional communication, which enables more precise positioning when the drone 2 is closer to the target position, can be initiated, allowing for efficient use of the power required for positioning processing using communication compliant with the UWB wireless communication standard.

[0140] Referring to Figure 15, another example of processing performed by the drone-side control device 21 or the port-side control device 31 will be described.

[0141] The drone-side control device 21 or the port-side control device 31 repeatedly determines the position of the drone 2 relative to the target position by periodically executing the positioning process described with reference to Figures 3 to 14. If this repetition period is T, the drone-side control device 21 or the port-side control device 31 may be configured to repeat the positioning process while slightly changing this period.

[0142] Specifically, the positioning process is initiated when the first start signal p1 is transmitted. Therefore, the drone-side control device 21 or the port-side control device 31 performs at least one of the following processes: lengthening the transmission period T of the first start signal p1 (changing it to T + ΔT) or shortening the transmission period T (changing it to T - ΔT).

[0143] This reduces the possibility of communication interference occurring due to the timing of the transmission of the first start signal p1 coincidentally matching that of other drones. This effect is particularly noticeable, for example, when multiple drones are landed at a base equipped with multiple landing ports.

[0144] To further reduce this possibility, it is preferable that the transmission timing of the first start signal p1 be determined randomly within the range of ΔT.

[0145] At least one of the drone-side control device 21 and the port-side control device 31, which have the various functions described above, is implemented by at least one dedicated integrated circuit equipped with a memory element on which a computer program for realizing the said function is pre-installed. Examples of dedicated integrated circuits include microcontrollers, ASICs, FPGAs, etc.

[0146] Alternatively, at least one of the drone-side control device 21 and the port-side control device 31 may be implemented by at least one general-purpose microprocessor operating in cooperation with at least one general-purpose memory. Examples of general-purpose microprocessors include CPUs, MPUs, and GPUs. Examples of general-purpose memory include ROMs and RAMs. In this case, the ROM may store a computer program for implementing the function. The general-purpose microprocessor selects at least a portion of the program stored in the ROM and loads it onto the RAM, and then executes the above-described process in cooperation with the RAM.

[0147] At least one of the drone-side control device 21 and the port-side control device 31 may be implemented by a combination of a general-purpose microprocessor and a dedicated integrated circuit.

[0148] The configurations described herein are merely examples to facilitate understanding of this disclosure. Each configuration example may be modified and combined with other configuration examples as appropriate, without departing from the spirit of this disclosure.

[0149] The "UWB wireless communication standard" used in the above embodiment example originates from a standardization standard compliant with IEEE 802.15. However, this expression is not intended to limit the scope to that standard. Any short-range wireless communication standard that has the advantages of being able to determine the relative positions of communication devices with high precision and having low power consumption and interference with other communications may be adopted.

[0150] In the above embodiment, the communication system 1 is used to determine the position of the drone 2 relative to the target position. However, the communication system 1 may also be used to determine the position of an aircraft capable of carrying a person. Alternatively, the communication system 1 may be used to determine the position of a mobile body other than the drone 2. Examples of such mobile bodies include vehicles, trains, and ships. Such mobile bodies do not necessarily require a driver.

[0151] The landing port 3 does not necessarily have to be installed on a permanent, stationary surface such as the ground or floor. The landing port 3 can be installed on part of a moving object such as a vehicle, train, or ship, as long as the relative positions of the multiple port-side communication devices do not change. In other words, the term "stationary object" as used in this disclosure includes any entity that can be considered substantially stationary from the perspective of the drone 2.

[0152] In part with respect to this disclosure, the contents of Japanese Patent Application No. 2024-232500, filed on 27 December 2024, are incorporated herein by reference.

Claims

1. A communication system comprising: a plurality of first communication devices mounted on one of a moving body and a stationary body; a plurality of second communication devices mounted on the other of the moving body and the stationary body; and a control device that determines the position of the moving body relative to a target position associated with the stationary body based on a first signal compliant with the UWB wireless communication standard transmitted from each of the plurality of first communication devices to the plurality of second communication devices.

2. The communication system according to claim 1, wherein the control device determines the position of the moving object relative to the target position based on a second signal compliant with the UWB wireless communication standard, which is transmitted from each of the plurality of second communication devices to the plurality of first communication devices as a response to the first signal.

3. The communication system according to claim 2, wherein the control device starts identifying the position using the second signal when the moving body enters a predetermined range from the target position.

4. The communication system according to claim 1, wherein the control device starts identifying the position using the first signal when the moving body enters a predetermined range from the target position.

5. The communication system according to any one of claims 1 to 4, wherein the control device determines the position of the moving body using position information provided by GPS until the moving body enters a predetermined range from the target position.

6. The communication system according to claim 2, wherein after the first signal is transmitted from N (where N is an integer of 2 or more) communication devices included in the plurality of first communication devices, the second signal is transmitted from M (where M is an integer less than or equal to N) communication devices included in the plurality of second communication devices.

7. The communication system according to any one of claims 1 to 6, wherein the plurality of first communication devices and the plurality of second communication devices are mounted on the stationary body and the mobile body, respectively, and the number of the plurality of second communication devices is less than the number of the plurality of first communication devices.

8. The communication system according to any one of claims 1 to 7, wherein the position of the moving object is repeatedly determined while changing the timing at which the first signal is transmitted.

9. The communication system according to claim 8, wherein the timing change is performed randomly within a predetermined range.

10. The communication system according to any one of claims 1 to 9, wherein the plurality of first communication devices are mounted on the immovable body.

11. The communication system according to any one of claims 1 to 9, wherein the plurality of first communication devices are mounted on the mobile body, and the control device transmits information relating to the location of the identified mobile body to the mobile body in a third signal that does not conform to the UWB wireless communication standard.

12. The communication system according to any one of claims 1 to 11, wherein the moving body is an aerial vehicle.

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