Control device, control method, and program

Abstract

[Problem] To provide a mechanism capable of improving the estimation accuracy of positional relationships in a multipath environment. [Solution] The control device includes a control unit that is disposed inside a target space partitioned by an object, receives an impulse radio signal including one or more pulses transmitted by another communication device, and estimates a position of the another communication device on the basis of an integrated value of a received power from the impulse radio signal received with a communication device over a prescribed time period.

Description

Control device, control method, and program

[0001] The present invention relates to a control device, a control method, and a program.

[0002] In recent years, techniques have been developed for estimating the positional relationship between a transmitter and a receiver by transmitting and receiving wireless signals. For example, Patent Literature 1 discloses a technique for estimating the distance between a transmitter and a receiver based on the power attenuation rate of received power relative to transmitted power.

[0003] Japanese Patent Application Laid-Open No. 2021-085719

[0004] However, since the received power can vary greatly in a multipath environment, the technique disclosed in Patent Document 1 may result in a decrease in the accuracy of distance estimation.

[0005] Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to provide a mechanism that can improve the accuracy of estimating positional relationships in a multipath environment.

[0006] In order to solve the above problem, according to one aspect of the present invention, there is provided a control device that is placed inside a target space partitioned by an object, receives an impulse radio signal including one or more pulses transmitted by another communication device, and estimates the position of the other communication device based on an integrated value of received power of the impulse radio signal received by the communication device over a predetermined time width.

[0007] In order to solve the above-mentioned problems, according to another aspect of the present invention, there is provided a control device that is placed inside a target space partitioned by an object, receives an impulse radio signal including one or more pulses transmitted by another communication device, and estimates the position of the other communication device based on an integrated value of CIR (Channel Impulse Response) values ​​calculated based on the impulse radio signal received by the communication device over a predetermined time width.

[0008] In order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a control method executed by a computer, the control method including: a communication device that is placed inside a target space partitioned by an object, receiving an impulse radio signal including one or more pulses transmitted by another communication device, and estimating a position of the other communication device based on an integrated value of received power of the impulse radio signal received by the communication device over a predetermined time width.

[0009] In order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a control method executed by a computer, the control method including: a communication device that is placed inside a target space partitioned by an object and receives an impulse radio signal including one or more pulses transmitted by another communication device; and estimating a position of the other communication device based on an integrated value over a predetermined time width of CIR values ​​calculated based on the impulse radio signal received by the communication device.

[0010] In order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a program for causing a computer to function as a control unit that is placed inside a target space partitioned by an object, receives an impulse radio signal including one or more pulses transmitted by another communication device, and estimates the position of the other communication device based on an integrated value of received power of the impulse radio signal received by the communication device over a predetermined time width.

[0011] In order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a program for causing a computer to function as a control unit that is placed inside a target space partitioned by an object, receives an impulse radio signal including one or more pulses transmitted by another communication device, and estimates the position of the other communication device based on an integrated value over a predetermined time width of CIR values ​​calculated based on the impulse radio signal received by the communication device.

[0012] As described above, according to the present invention, a mechanism is provided that can improve the accuracy of estimating the positional relationship in a multipath environment.

[0013] FIG. 1 is a block diagram showing an example of the functional configuration of a control system according to an embodiment of the present invention. FIG. 2 is a diagram for explaining detailed functions of the control system according to the present embodiment. FIG. 3 is a diagram for explaining detailed functions of the control system according to the present embodiment. FIG. 4 is a flowchart showing an example of the flow of processing executed by the control system according to the present embodiment. FIG. 5 is a diagram for explaining a modified example of the placement of communication devices. FIG. 6 is a diagram for explaining a modified example of the placement of communication devices.

[0014] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant explanations will be omitted.

[0015] In addition, in this specification and drawings, when multiple identical components are to be described separately, letters or the like may be added to the end of the reference numerals. On the other hand, when it is not necessary to distinguish between multiple identical components, the letters or the like may be omitted and a description common to all of the multiple identical components may be given.

[0016] <1. Embodiment> <1.1. System Configuration Example> First, a functional configuration example of a control system 1 according to an embodiment of the present invention will be described.

[0017] FIG. 1 is a block diagram showing an example of the functional configuration of a control system 1 according to an embodiment of the present invention.

[0018] As shown in FIG. 1, a control system 1 according to this embodiment includes a moving object 10 and a portable device 20 .

[0019] As shown in FIG. 1, a mobile object 10 according to this embodiment is equipped with a communication device 110, a control device 120, and a controlled device 130.

[0020] The portable device 20 according to this embodiment is also equipped with a communication device 210 and has a control application 220 installed therein.

[0021] (Mobile object 10) The mobile object 10 according to this embodiment may be a vehicle such as a car, an aircraft, or a ship.

[0022] (Communication Device 110) The communication device 110 according to this embodiment performs wireless communication with a communication device 210 mounted on the portable device 20 in accordance with a prescribed communication standard.

[0023] The prescribed communication standard may be, for example, one that uses an impulse radio signal. An impulse radio signal is a signal that includes short, wideband pulses. Specifically, the prescribed communication standard may be one that uses an ultra-wide band (UWB) radio signal.

[0024] However, the prescribed communication standard is not limited to the above example, and may be set arbitrarily.

[0025] The mobile object 10 may be equipped with one or more communication devices 110 .

[0026] (Control Device 120 ) The control device 120 according to this embodiment includes a control unit that controls the execution of a prescribed operation by the controlled device 130 based on the result of communication by the communication device 110 .

[0027] The functions of the control device 120 according to this embodiment are realized by various processors. The details of the functions of the control device 120 according to this embodiment will be described later.

[0028] (Controlled Device 130 ) The controlled device 130 according to this embodiment may be any of various devices that perform a specified operation under the control of the control device 120 .

[0029] As shown in Figure 1, when the controlled device 130 is mounted on a mobile body 10, the controlled device 130 may be, for example, a locking / unlocking device that locks / unlocks a door provided on the mobile body 10 as the above-mentioned specified operation.

[0030] However, controlled device 130 and the prescribed operation are not limited to the above example.

[0031] For example, controlled device 130 may be an engine. In this case, the specified action may be to permit or restrict engine start.

[0032] Furthermore, for example, controlled device 130 may be a lighting device. In this case, the specified operation may be to turn on or off the light.

[0033] (Portable Device 20) The portable device 20 according to this embodiment is carried by the user of the mobile object 10 (for example, the owner of the mobile object 10, or a person authorized by the owner to use the mobile object 10, etc.).

[0034] The portable device 20 according to this embodiment may be, for example, a smartphone, a tablet, a wearable device, or the like.

[0035] (Communication Device 210) The communication device 210 according to this embodiment performs wireless communication with the communication device 110 mounted on the mobile object 10 in accordance with a prescribed communication standard.

[0036] (Control Application 220) The control application 220 according to this embodiment includes at least a program for controlling the above-described wireless communication by the communication device 210.

[0037] The above has described an example of the functional configuration of the control system 1 according to this embodiment. Note that the functional configuration described above with reference to Fig. 1 is merely an example, and the functional configuration of the control system 1 according to this embodiment is not limited to this example.

[0038] The functional configuration of the control system 1 according to this embodiment can be flexibly modified according to specifications, operation, and the like.

[0039] <1.2. Detailed Functions> Next, the functions of the control system 1 according to this embodiment will be described in detail with reference to FIGS.

[0040] 2 to 4 are diagrams for explaining detailed functions of the control system 1 according to this embodiment.

[0041] 2 , a communication device 110 is disposed on a ceiling portion inside a vehicle cabin 11 of a vehicle serving as a moving body 10. The vehicle cabin 11 is an example of a target section partitioned by an object. The vehicle is an example of an object that partitions the vehicle cabin 11.

[0042] However, the vehicle interior 11 is also partitioned by a member that transmits radio waves, such as a window glass 12. Therefore, even when the portable device 20 is located outside the vehicle interior 11, communication between the portable device 20 and the communication device 110 is possible.

[0043] The portable device 20 transmits an impulse radio signal S including one or more pulses. The communication device 110 receives the impulse radio signal S transmitted by the portable device 20.

[0044] The control device 120 then estimates the position of the portable device 20 based on the received power (e.g., RSSI (Received Signal Strength Indicator)) of the impulse radio signal S received by the communication device 110. In this case, the control device 120 estimates the position of the portable device 20 based on the integrated value of the received power of the impulse radio signal S received by the communication device 110 within a predetermined time width T. With this configuration, it is possible to improve the accuracy of estimating the position of the portable device 20, as will be described below.

[0045] Graph G shows the time series transition of the received power of the impulse radio signal S received by the communication device 110, with the horizontal axis representing time and the vertical axis representing received power. Referring to graph G shown in Fig. 2, it can be seen that multiple waveforms W1 to W3 are received spaced apart in the time direction.

[0046] W1 is a waveform corresponding to a direct wave. A direct wave is a signal that travels the shortest path between the transmitter and receiver and is received directly (i.e., without being reflected) by the receiver.

[0047] W2 and W3 are waveforms corresponding to reflected waves, which are signals received by the receiving side via a path that includes reflections.

[0048] As described above with respect to Patent Document 1, the received power may fluctuate significantly in a multipath environment, which may result in a decrease in the accuracy of the estimation if the position of the portable device 20 is estimated based only on the received power of the waveform W1, which corresponds to the direct wave.

[0049] By using the impulse radio signal S, it becomes possible to separate multipath waves in terms of time, improving estimation accuracy. However, when the portable device 20 is located near the moving body 10 even if it is outside the vehicle compartment 11, there is a risk that the portable device 20 will be erroneously estimated to be located inside the vehicle compartment 11. This is because in such a positional relationship, the distance between the transmitter and receiver is short, resulting in a large received power, and the difference from the received power when the portable device 20 is located inside the vehicle compartment 11 is small.

[0050] Therefore, the control device 120 according to this embodiment estimates the position of the portable device 20 based on the integrated value of the received power of the impulse radio signal S received within a predetermined time width T, i.e., the integrated value of the received power of the waveforms W1 to W3. With this configuration, the relationship in magnitude of the received power corresponding to the relationship in magnitude of the distance between the transmitter and receiver becomes so clear that it can be easily distinguished by the integration, and therefore it is possible to improve the accuracy of estimating the position of the portable device 20.

[0051] 2, the predetermined time width T is longer than the time width of the pulses contained in the impulse radio signal S. With this configuration, it is possible to integrate the received power of multiple pulses and use the integrated power for position estimation.

[0052] On the other hand, the predetermined time width T is shorter than the transmission interval of the impulse radio signal S. With this configuration, even if the portable device 20 transmits the impulse radio signal S multiple times, the object of integration can be limited to the received power when the impulse radio signal S is transmitted once. As a result, it is possible to suppress variations in the accuracy of the location estimation of the portable device 20.

[0053] It should be noted that estimation based on the integrated value is effective precisely because the transmitted and received signals are impulse radio signals S. This is because, as shown in graph G in Fig. 2, multiple impulse radio signals S received by the receiving side after passing through multiple paths can be separated in the time domain. If the transmitted and received signals were sine waves, signals with opposite phases would cancel each other out, making it difficult to separate multiple sine waves received by the receiving side after passing through multiple paths in the time domain, and making estimation based on the integrated value difficult.

[0054] 3, when the portable device 20 is located inside the vehicle interior 11, the impulse radio signal S that has passed through many paths is received by the communication device 110 as a direct wave indicated by the solid line or a reflected wave indicated by the dashed line. As a result, as shown in graph G in FIG. 3, a waveform W1 corresponding to the direct wave and waveforms W2 and W3 corresponding to the reflected waves are received by the communication device 110, and the integrated value over a predetermined time width T becomes large.

[0055] On the other hand, as shown in Fig. 4, when the portable device 20 is located outside the vehicle interior 11, the impulse radio signal S, which has traveled through fewer paths than in the example shown in Fig. 3, is received by the communication device 110 as a direct wave indicated by the solid line or a reflected wave indicated by the dashed line. This is because the signal cannot reach the communication device 110 unless it has passed through the window glass 12. As a result, as shown in graph G in Fig. 4, a waveform W1 corresponding to a direct wave and a waveform W2 corresponding to a reflected wave are received by the communication device 110, and therefore the integrated value over a predetermined time width T is smaller than in the example shown in Fig. 3.

[0056] In this way, the difference in the integrated value of the received power over a predetermined time period T between when the portable device 20 is located inside the vehicle compartment 11 and when it is located outside the vehicle compartment 11 is larger than the difference in the received power of only the direct wave.

[0057] Therefore, when the integrated value of the received power of the impulse radio signal S received by the communication device 110 during the predetermined time interval T is greater than a predetermined threshold, the control device 120 estimates that the portable device 20 is located inside the vehicle interior 11. On the other hand, when the integrated value of the received power of the impulse radio signal S received by the communication device 110 during the predetermined time interval T is smaller than or equal to the predetermined threshold, the control device 120 estimates that the portable device 20 is located outside the vehicle interior 11.

[0058] This configuration makes it possible to improve the accuracy of estimating whether the portable device 20 is located inside or outside the vehicle interior 11. In particular, even if the communication device 110 is placed in a position that can be seen from outside the vehicle interior 11, such as on the ceiling inside the vehicle interior 11, it is possible to accurately determine whether the portable device 20 is located inside or outside the vehicle interior 11.

[0059] <1.3. Processing Flow> Next, an example of the processing flow executed by the control system 1 according to this embodiment will be described with reference to FIG.

[0060] FIG. 5 is a flowchart showing an example of the flow of processing executed by the control system 1 according to this embodiment.

[0061] As shown in FIG. 5, first, the portable device 20 transmits an impulse radio signal S, and the communication device 110 receives the impulse radio signal S transmitted from the portable device 20 (step S102).

[0062] Next, the control device 120 calculates the integrated value of the received power of the impulse radio signal S received by the communication device 110 within the predetermined time duration T (step S104).

[0063] Next, the control device 120 estimates the location area of ​​the portable device 20 based on the calculated integrated value (step S106). For example, if the integrated value is greater than a predetermined threshold, the control device 120 estimates that the portable device 20 is located inside the vehicle interior 11, and if not, the control device 120 estimates that the portable device 20 is located outside the vehicle interior 11.

[0064] Then, the control device 120 controls the operation of the controlled device 130 based on the result of estimating the location area of ​​the portable device 20 (step S108). For example, when the control device 120 estimates that the portable device 20 is located inside the vehicle interior 11, the control device 120 permits the engine to start.

[0065] <2. Supplementary Information> Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical idea described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0066] (First Modification) The portable device 20 may transmit a plurality of impulse radio signals S. In this case, the communication device 110 receives the plurality of impulse radio signals S. The control device 120 may then calculate an integrated value over a predetermined time width T for each of the plurality of impulse radio signals S received by the communication device 110, and estimate the position of the portable device 20 based on the calculated integrated values.

[0067] In this case, the control device 120 may estimate the position of the portable device 20 based on a statistical value of a plurality of integrated values ​​calculated for a plurality of impulse radio signals S. Examples of the statistical value here include an average value, a weighted average value, or a median value.

[0068] According to this configuration, it is possible to further improve the accuracy of estimating the position of the portable device 20.

[0069] (Second Modification) A plurality of communication devices 110 may be arranged inside the vehicle interior 11. In this case, the control device 120 may calculate an integrated value for a predetermined time width T for each of a plurality of impulse radio signals S received by the plurality of communication devices 110, and estimate the position of the portable device 20 based on the calculated integrated values.

[0070] In this case, the control device 120 may estimate that the portable device 20 is located inside the vehicle interior 11 when all of the multiple integrated values ​​calculated for the multiple communication devices 110 are greater than a predetermined threshold. On the other hand, the control device 120 may estimate that the portable device 20 is located outside the vehicle interior 11 when at least some of the multiple integrated values ​​calculated for the multiple communication devices 110 are smaller than or equal to the predetermined threshold.

[0071] According to this configuration, it is possible to further improve the accuracy of estimating the position of the portable device 20.

[0072] It should be noted that this modification and the first modification may be combined.

[0073] (Third Modification) The control device 120 may calculate a channel impulse response (CIR) based on the impulse radio signal S received by the communication device 110. The control device 120 may calculate the CIR by performing a sliding correlation between the received signal and a known transmitted signal. The control device 120 may then estimate the position of the portable device 20 based on an integrated value of the CIR value over a predetermined time interval T.

[0074] The processing by the control device 120 according to this modification is the same as that of the above embodiment, except that the CIR value is used instead of the received power.

[0075] With this configuration, the magnitude relationship of the CIR values ​​corresponding to the magnitude relationship of the distance between the transmitter and receiver becomes clear enough to be easily distinguished by accumulation, making it possible to improve the accuracy of estimating the position of the portable device 20.

[0076] This modification may be combined with the first modification and / or the second modification.

[0077] 2 to 4, the communication device 110 may be disposed on the ceiling of the vehicle interior 11. In this case, it is possible to ensure a wide communication area with the portable device 20 outside the vehicle interior 11.

[0078] However, the arrangement of the communication device 110 is not limited to this example. Modified examples of the arrangement of the communication device 110 will be described with reference to FIGS.

[0079] Fig. 6 is a diagram illustrating a modified example of the arrangement of the communication device 110. As shown in Fig. 6, multiple communication devices 110 (110L and 110R) may be arranged on the ceiling of the vehicle interior 11 at positions spaced apart in the left-right direction of the vehicle as the moving body 10. With such an arrangement, a wide communication area with the portable device 20 outside the vehicle interior 11 can be secured, and the accuracy of estimating the position of the portable device 20 can be improved.

[0080] Specifically, since communication device 110L is disposed to the left of the center and near left window glass 12L, it is possible to ensure a wide communication area with portable device 20 in the left direction. Similarly, since communication device 110R is disposed to the right of the center and near right window glass 12R, it is possible to ensure a wide communication area with portable device 20 in the right direction.

[0081] Furthermore, with such an arrangement, it is possible to refer to multiple received powers obtained by multiple communication devices 110, thereby further improving the accuracy of estimating whether the portable device 20 is located inside or outside the vehicle cabin 11.

[0082] 7 is a diagram illustrating another example of the placement positions of the communication devices 110. As shown in Fig. 7, multiple communication devices 110 (110F and 110B) may be placed on the ceiling of the vehicle interior 11 at positions spaced apart in the fore-and-aft direction of the vehicle as the moving body 10. This placement can ensure a wide communication area with the portable device 20 outside the vehicle interior 11 and improve the accuracy of estimating the position of the portable device 20.

[0083] Specifically, because communication device 110F is disposed forward of the center, it is possible to ensure a wide communication area in the forward direction with portable device 20. Similarly, because communication device 110B is disposed rearward of the center, it is possible to ensure a wide communication area in the rearward direction with portable device 20. When mobile object 10 is long in the front-to-rear direction, such as a vehicle, this arrangement is advantageous in that it can ensure a long communication area in the front-to-rear direction.

[0084] Furthermore, with such an arrangement, it is possible to refer to multiple received powers obtained by multiple communication devices 110, thereby further improving the accuracy of estimating whether the portable device 20 is located inside or outside the vehicle cabin 11.

[0085] (Other) The application of the present invention is not limited to the moving body 10. In other words, the communication device 110 may be placed inside a target space partitioned by an object, and the placement of the communication device 110 is not limited to inside the vehicle cabin 11. For example, the communication device 110 may be placed inside a room, and the control device 120 may estimate whether the portable device 20 is located inside or outside the room.

[0086] The series of processes performed by each device described herein may be implemented using software, hardware, or a combination of software and hardware. The software programs may be stored in advance, for example, on a recording medium (more specifically, a non-transitory computer-readable storage medium) internal or external to each device. Each program is then loaded into a random access memory (RAM) and executed by a processing circuit such as a central processing unit (CPU). The recording medium may be, for example, a magnetic disk, an optical disk, a magneto-optical disk, or a flash memory. The computer program may also be distributed, for example, via a network, without using a recording medium. The computer may be, for example, an application-specific integrated circuit (ASIC), a general-purpose processor that executes functions by loading a software program, or a computer on a server used in cloud computing. The series of processes performed by each device described herein may be centrally processed by a single computer or distributed across multiple computers. Furthermore, in each of the above embodiments, two or more communication means present in a single device may be physically implemented on a single medium.

[0087] Furthermore, the processes described herein using flowcharts or sequence diagrams do not necessarily have to be performed in the order shown. Some process steps may be performed in parallel. Furthermore, additional process steps may be employed, and some process steps may be omitted.

[0088] 1: Control system, 10: Mobile object, 11: Vehicle interior, 12: Window glass, 110: Communication device, 120: Control device, 130: Controlled device, 20: Portable device, 210: Communication device, 220: Control application

Claims

1. A control device comprising: a control unit that is placed inside a target space partitioned by an object, receives an impulse radio signal including one or more pulses transmitted by another communication device, and estimates the position of the other communication device based on an integrated value of the received power of the impulse radio signal received by the communication device over a specified time width.

2. The control device according to claim 1, wherein the predetermined time width is longer than the time width of the pulse contained in the impulse radio signal and shorter than a transmission interval of the impulse radio signal.

3. The control device according to claim 1, wherein the control unit estimates that the other communication device is located inside the target space when the integrated value is greater than a predetermined threshold value.

4. The control device according to claim 1, wherein the communication device receives a plurality of the impulse radio signals, and the control unit calculates the integrated value for each of the plurality of impulse radio signals received by the communication device, and estimates the position of the other communication device based on the plurality of integrated values.

5. The control device according to claim 1, wherein a plurality of the communication devices are arranged within the target space, and the control unit calculates the integrated value for each of a plurality of the impulse radio signals received by the plurality of the communication devices, and estimates the position of the other communication device based on the plurality of integrated values.

6. The control device according to any one of claims 1 to 5, wherein the object is a vehicle, and the target space is a vehicle interior.

7. The control device according to claim 6, wherein the communication device is disposed on a ceiling of the vehicle compartment.

8. The control device according to claim 6, wherein a plurality of the communication devices are arranged on the ceiling of the vehicle compartment at positions spaced apart in the left-right direction of the vehicle.

9. The control device according to claim 6, wherein a plurality of the communication devices are arranged on the ceiling of the passenger compartment at positions spaced apart in the fore-and-aft direction of the vehicle.

10. A control device comprising: a control unit that is placed within a target space partitioned by an object, receives an impulse radio signal including one or more pulses transmitted by another communication device, and estimates the position of the other communication device based on an integrated value of a channel impulse response (CIR) value calculated based on the impulse radio signal received by the communication device over a specified time period.

11. A control method executed by a computer, comprising: a communication device that is placed within a target space partitioned by an object and receives an impulse radio signal including one or more pulses transmitted by another communication device, and estimating a position of the other communication device based on an integrated value of received power of the impulse radio signal received by the communication device over a predetermined time width.

12. A control method executed by a computer, comprising: a communication device that is placed within a target space partitioned by an object and receives an impulse radio signal including one or more pulses transmitted by another communication device, and estimating a position of the other communication device based on an integrated value over a predetermined time width of a CIR value calculated based on the impulse radio signal received by the communication device.

13. A program for causing a computer to function as a control unit that is placed inside a target space partitioned by an object, receives an impulse radio signal containing one or more pulses transmitted by another communication device, and estimates the position of the other communication device based on the integrated value of the received power of the impulse radio signal received by the communication device over a specified time width.

14. A program for causing a computer to function as a control unit that is placed inside a target space partitioned by an object, receives an impulse radio signal containing one or more pulses transmitted by another communication device, and estimates the position of the other communication device based on an integrated value over a specified time width of a CIR value calculated based on the impulse radio signal received by the communication device.

Images