JP7715079B2 - Information processing device - Google Patents

Description

The present invention relates to an information processing device.

Technology has been proposed for determining the distance to an object near a vehicle through short-range communication. For example, Patent Document 1 discloses a technology that determines whether a mobile communication device that transmitted a signal is present near the vehicle based on changes in the strength of the signal received by an antenna.

Specifically, Patent Document 1 describes how arranging multiple antennas so that they are offset in the vehicle width direction prevents the overlap of minimum values in the power attenuation curve. Then, the system determines whether a mobile communication device is present near the vehicle based on whether the signal strength of the multiple antennas is increasing or decreasing.

Japanese Patent Application Laid-Open No. 2021-096119

However, the technology described in Patent Document 1 determines whether or not a mobile communication device is present in the vicinity of a vehicle based on signal strength, and does not take into account the direction of the signal received by the antenna, making it difficult to pinpoint the specific location of the mobile terminal. For example, when the technology described in Patent Document 1 is applied to a situation where there are multiple detection targets, if it is determined that the multiple detection targets are at the same distance, it is difficult to determine whether the multiple detection targets are present in the same location.

As such, when multiple wireless transmitting devices are targeted for detection, it is possible that when one of them moves outside the vehicle, the other may be determined to be at the same distance from the antenna, even if it is inside the vehicle. For this reason, it is difficult to use the technology described in Patent Document 1 to detect items left behind when a user exits a vehicle.

In light of the above issues, the objective is to provide a technology that calculates the location information of multiple wireless transmitting devices based on received signals from the multiple wireless transmitting devices, and then alerts the user when an object equipped with one of the wireless transmitting devices is present inside the vehicle when the user carrying the other wireless transmitting device moves outside the vehicle.

In order to achieve the above-mentioned object, one embodiment of the present disclosure provides an information processing device comprising : a first acquisition unit that acquires, from each of three or more wireless receiving devices provided at positions corresponding to each vertex of a rectangle formed by the sides in the vehicle's traveling direction and the sides in the vehicle's width direction , first signal strength information indicating the strength of a received signal received by the wireless receiving device from a first wireless transmitting device; a second acquisition unit that acquires, from each of the three or more wireless receiving devices, second signal strength information indicating the strength of a received signal received by the wireless receiving device from a second wireless transmitting device; a calculation unit that calculates first position information indicating the position where the first wireless transmitting device is located based on the first signal strength information and second position information indicating the position where the second wireless transmitting device is located based on the second signal strength information; and an output unit that outputs alarm information to a mobile communication device when the position indicated by the first position information is not included in the inner area of the vehicle and the position indicated by the second position information is included in the inner area of the vehicle.

The above-described embodiment provides technology that prevents a situation in which an object is left behind inside the vehicle by alerting the user if an object is present inside the vehicle when the user moves outside the vehicle.

FIG. 1 is a diagram showing an example of a schematic configuration of an object position detection system provided in a vehicle according to the first embodiment. FIG. 2 is a block diagram illustrating the configuration of an object position detection system for a vehicle according to the first embodiment. FIG. 3 is a diagram illustrating a method for calculating a position based on the intensity of radio waves in the position calculation unit according to the first embodiment. FIG. 4 is a flowchart showing control relating to notification when a left-behind item is detected by the in-vehicle device according to the first embodiment.

The following describes the embodiments of the invention with reference to the drawings.

[Configuration of the first embodiment]
Fig. 1 is a diagram showing an example of a schematic configuration of an object location detection system provided in a vehicle according to embodiment 1. The object location detection system shown in Fig. 1 has four receiving devices (examples of wireless receiving devices) 20_1 to 20_4 provided in a vehicle 10, an in-vehicle device 30, and a wireless communication device 31.

In the example shown in FIG. 1, a user (e.g., a vehicle driver) carries a mobile communication device 100 and a smart key 110 for the vehicle 10. Also in the example shown in FIG. 1, a wallet 111 is present in the vehicle.

The mobile communication device 100 is a terminal capable of sending and receiving signals via wireless communication, and is, for example, a general-purpose mobile terminal such as a tablet terminal or smartphone carried by a user. The mobile communication device 100 may also be a general-purpose stationary terminal such as a laptop computer terminal or a desktop computer.

Smart key 110 (an example of a first wireless transmitting device) is a terminal capable of locking and unlocking the doors of vehicle 10, and includes a wireless transmitting/receiving device capable of transmitting and receiving signals via wireless communication with receiving devices 20_1 to 20_4 installed in vehicle 10. Smart key 110 according to this embodiment transmits and receives signals via wireless communication with receiving devices 20_1 to 20_4 at predetermined intervals.

Wallet 111 stores wireless transmitting tag 111A. Wireless transmitting tag 111A is a wireless transmitting device (an example of a second wireless transmitting device) capable of transmitting signals via wireless communication. Wireless transmitting tag 111A in this embodiment transmits and receives signals via wireless communication with receiving devices 20_1 to 20_4 at predetermined intervals.

Vehicle 10 may be any vehicle that a user can board. In Figure 1, a four-wheeled automobile is used as an example of vehicle 10. Furthermore, vehicle 10 is not limited to automobiles with gasoline engines, and may also be a hybrid vehicle or an electric vehicle. Furthermore, vehicle 10 is not limited to automobiles, and may also be other vehicles (for example, railroad cars).

The vehicle 10 shown in Figure 1 has doors on both the left and right sides to allow users to get in and out of the vehicle. Users can get in and out of the vehicle 10 freely by opening the doors provided on the vehicle 10.

Each of the receiving devices 20_1 to 20_4 has a receiving antenna and is configured to detect radio waves transmitted by the smart key 110 and the radio transmitting tag 111A. In this embodiment, the receiving devices 20_1 to 20_4 acquire the strength (RSSI) of the received radio waves when the receiving antenna receives the radio waves.

The four receiving devices 20_1 to 20_4 are composed of a right front receiving device 20_1, a left front receiving device 20_2, a right rear receiving device 20_3, and a left rear receiving device 20_4. Specifically, each of the four receiving devices 20_1 to 20_4 is located near the vertices of a rectangle formed by a side in the direction of travel of the vehicle 10 (X-axis direction) and a side in the width direction of the vehicle 10 (Y-axis direction) on a plane approximately parallel to the plane on which the vehicle 10 is traveling.

Specifically, the receiving antenna of the right front receiving device 20_1 is located near the right front end of the vehicle 10. The receiving antenna of the left front receiving device 20_2 is located near the left front end of the vehicle 10. The receiving antenna of the right rear receiving device 20_3 is located near the right rear end of the vehicle 10. The receiving antenna of the left rear receiving device 20_4 is located near the left rear end of the vehicle 10. In other words, because the four receiving antennas are located at different positions in the traveling direction and width direction of the vehicle 10, the received signal strength changes depending on the changes in the traveling direction and width direction positions of the smart key 110 and the wireless transmitting tag 111A.

In other words, in this embodiment, changes in the location of the smart key 110 and the wireless transmitting tag 111A inside or around the vehicle 10 can be detected based on changes in the radio wave intensity received by the receiving antennas of the receiving devices 20_1 to 20_4.

These are examples of locations where the receiving antennas of the four receiving devices 20_1 to 20_4 according to this embodiment may be installed, and are not limited to these locations. The receiving antennas of the four receiving devices 20_1 to 20_4 may be installed so that their locations can be identified from the radio waves transmitted by the smart key 110 and the wireless transmitting tag 111A. For example, the receiving antennas of the four receiving devices 20_1 to 20_4 may be installed on the front pillars and rear pillars of the vehicle 10.

The receiving devices 20_1 to 20_4 and the in-vehicle device 30 are connected via an external bus 25. The external bus 25 may be, for example, a Controller Area Network (CAN), or may be connected via another network.

The wireless communication device 31 performs wireless communication with an external communication device (mobile communication device 100). Examples of wireless communication include short-range wireless communication lines such as Wi-Fi (registered trademark) and Bluetooth (registered trademark). Furthermore, the wireless communication device 31 may use communication standards such as 5G (fifth generation mobile communication system), LTE (Long Term Evolution), or Wi-Fi (registered trademark).

In-vehicle device 30 (an example of an information processing device) has the function of acquiring reception information based on signals received by receiving devices 20_1 to 20_4 and performing various processes based on the received information. In addition, in-vehicle device 30 is connected to wireless communication device 31, and is capable of outputting information via wireless communication to an external communication device via wireless communication device 31.

The example shown in Figure 1 shows a situation in which the user leaves the vehicle 10 while carrying the smart key 110 and the mobile communication device 100. At that time, the user forgets to carry the wallet 111.

In other words, when the in-vehicle device 30 detects that the smart key 110 is outside the vehicle 10 and that the wireless transmitting tag 111A of the wallet 111 is inside the vehicle, the in-vehicle device 30 transmits notification information to the mobile communication device 100 via the wireless communication device 31, indicating that an item has been left behind inside the vehicle 10. This allows the user to recognize that an item has been left behind inside the vehicle 10.

Note that this embodiment shows an example of a notification of a lost item and is not limited to the above-mentioned situation. For example, if the in-vehicle device 30 detects that the wallet 111 is outside the vehicle 10 and that the smart key 110 is inside the vehicle, the in-vehicle device 30 may send notification information to the mobile communication device 100 indicating that a lost item is inside the vehicle 10.

Furthermore, in this embodiment, the detection targets of the receiving devices 20_1 to 20_4 are not limited to the smart key 110 and the wireless transmitting tag 111A of the wallet 111, but may be any device capable of transmitting wireless communication signals.

Figure 2 is a block diagram illustrating the configuration of an object position detection system for a vehicle 10 according to this embodiment. As shown in Figure 1, the vehicle 10 includes a right front receiving device 20_1, a left front receiving device 20_2, a right rear receiving device 20_3, a left rear receiving device 20_4, a wireless communication device 31, and an in-vehicle device 30.

The in-vehicle device 30 has a CPU (Central Processing Unit) 301, a storage device 302, a RAM (Random Access Memory) 304, an in-vehicle communication I/F (interface) 305, and an input/output I/F 303. The CPU 301, storage device 302, RAM 304, in-vehicle communication I/F 305, and input/output I/F 303 are connected to each other so that they can communicate with each other via an internal bus 306.

For example, the CPU 301 performs various controls related to detecting the position of an object by executing various programs stored in the storage device 302. The CPU 301 may allocate a working area in the RAM 304 for storing data used to execute the various programs.

The storage device 302 pre-stores various programs and data such as initial setting values. The various programs stored in the storage device 302 include a control program for controlling the in-vehicle device 30. The storage device 302 is used as a work area for the CPU 301, and temporarily stores work data, programs, etc.

The storage device 302 includes an antenna information storage unit 321 and an area information storage unit 322.

The antenna information storage unit 321 stores position information for the receiving antennas of the receiving devices 20_1 to 20_4, based on a predetermined position of the vehicle 10. For example, the antenna information storage unit 321 stores information indicating the position coordinates of each of the receiving antennas of the receiving devices 20_1 to 20_4 in a coordinate system that has a predetermined position of the vehicle 10 (e.g., the center of gravity of the vehicle 10) as the origin and includes the X-axis direction (direction of travel) and the Y-axis direction (vehicle width direction). Note that the coordinate system used in this embodiment only needs to include the X-axis direction (direction of travel) and the Y-axis direction (vehicle width direction), and may be a two-dimensional coordinate system or a three-dimensional coordinate system that also includes the Z-axis direction (height direction).

The area information storage unit 322 stores coordinate information indicating areas inside the vehicle 10 in the coordinate system held by the antenna information storage unit 321. Furthermore, the area information storage unit 322 may store coordinate information corresponding to each area within the vehicle 10 (e.g., rear left seat, rear right seat, front left seat, front right seat).

The in-vehicle communication I/F 305 is connected to multiple receiving devices 20_1 to 20_4 via the external bus 25. For example, the in-vehicle communication I/F 305 transmits and receives communication frames based on the CAN protocol between the in-vehicle device 30 and each of the receiving devices 20_1 to 20_4. Note that the in-vehicle communication I/F 305 may also perform communication using Ethernet (registered trademark).

The input/output I/F 303 is connected to a wireless communication device 31 or the like installed in the vehicle 10, and transmits and receives various information. Note that the input/output I/F 303 in this embodiment is not limited to connecting to the wireless communication device 31, and may also be connected to, for example, a speaker, a monitor, etc.

The CPU 301 calculates the location information of the smart key 110 and the wireless transmitting tag 111A of the wallet 111 based on the strength of the radio waves (RSSI) received from each of the multiple receiving devices 20_1 to 20_4 via the in-vehicle communication I/F 305.

The CPU 301 according to this embodiment includes, for example, a key information acquisition unit 311, a tag information acquisition unit 312, a position calculation unit 313, a determination unit 314, and an output unit 315 as functional units realized by executing one or more programs installed in the storage device 302.

The key information acquisition unit 311 (an example of a first acquisition unit) acquires information about the smart key 110 from radio waves received by each of the multiple receiving devices 20_1 to 20_4. The acquired information includes first signal strength information (RSSI) that indicates the strength of the received signal from the smart key 110 (an example of a first wireless transmitting device) received by each of the receiving devices 20_1 to 20_4.

Any method, including well-known methods, may be used to identify the signal transmitted by the smart key 110 from among the signals acquired by the multiple receiving devices 20_1 to 20_4 (an example of a wireless receiving device). For example, the source of the radio waves received by each of the receiving devices 20_1 to 20_4 may be identified based on the signal contained in the radio waves. For this reason, the smart key 110 may include information identifying the smart key 110 (e.g., an ID) in the radio waves it transmits.

The tag information acquisition unit 312 (an example of a second acquisition unit) acquires information about the wireless transmitting tag 111A from the radio waves received by each of the multiple receiving devices 20_1 to 20_4. The acquired information includes second signal strength information (RSSI) that indicates the strength of the received signal from the wireless transmitting tag 111A (an example of a second wireless transmitting device) received by each of the receiving devices 20_1 to 20_4. The method for identifying the signal transmitted by the smart key 110 from the signals acquired by the multiple receiving devices 20_1 to 20_4 is the same as the method for identifying the signal transmitted by the wireless transmitting tag 111A.

The position calculation unit 313 calculates position coordinates (an example of first position information) indicating the location of the smart key 110 (an example of a first wireless transmitting device) based on the first signal strength information, and position coordinates (an example of second position information) indicating the location of the wireless transmitting tag 111A (an example of a second wireless transmitting device) based on the second signal strength information.

For example, the position calculation unit 313 calculates the position coordinates of the wireless transmitting tag 111A based on the second signal strength information (RSSI) acquired by the tag information acquisition unit 312 and the position coordinates of each of the receiving antennas of the receiving devices 20_1 to 20_4 stored in the antenna information storage unit 321.

There is a correspondence between the strength of the radio waves received by a receiving antenna and the distance to the receiving antenna. For example, in free space, RSSI tends to attenuate inversely proportional to the square of the distance. For this reason, the position calculation unit 313 calculates the distance from the wireless transmitting tag 111A to each of the four receiving antennas based on the first signal strength information (RSSI). Then, the position calculation unit 313 calculates the position coordinates of the wireless transmitting tag 111A based on the distance to each of the four receiving antennas and the position coordinates of the receiving antennas.

Figure 3 is a diagram illustrating a method for calculating a position based on radio wave intensity in the position calculation unit 313 according to this embodiment. In the example shown in Figure 3, the receiving antennas of receiving devices 20_1 to 20_4 are placed at the four corners of the vehicle 10. As a result, if a device is within the range of area 250 inside the receiving antennas of receiving devices 20_1 to 20_4, it can be recognized as being inside the vehicle 10.

In the example shown in FIG. 3, distance 200_1 (from the receiving antenna) calculated from the strength (RSSI) of the received signal received by the right front receiving device 20_1 is shown. Also shown is distance 200_2 (from the receiving antenna) calculated from the strength (RSSI) of the received signal received by the left front receiving device 20_2. Also shown is distance 200_3 (from the receiving antenna) calculated from the strength (RSSI) of the received signal received by the right rear receiving device 20_3. Also shown is distance 200_4 (from the receiving antenna) calculated from the strength (RSSI) of the received signal received by the left rear receiving device 20_4.

The position calculation unit 313 then calculates the intersection of the calculated distances 200_1 to 200_4 as the position coordinates of the detection target (e.g., the wireless transmitting tag 111A).

Similarly, the position calculation unit 313 calculates the position coordinates of the smart key 110 based on the first signal strength information (RSSI) acquired by the key information acquisition unit 311 and the position coordinates of each of the receiving antennas of the receiving devices 20_1 to 20_4 stored in the antenna information storage unit 321.

In this embodiment, the receiving antennas of receiving devices 20_1 to 20_4 are located at the four corners of vehicle 10. This makes it possible to determine whether a detection target is inside vehicle 10 based on whether it is within area 250. Note that the method for determining whether a detection target is inside vehicle 10 is not limited to this method, and any method that stores coordinate information for an area corresponding to the inside of vehicle 10 will do.

In this embodiment, the receiving devices 20_1 to 20_4 installed on the vehicle 10 are arranged as described above so that the distance between them is as great as possible. In other words, because the receiving devices 20_1 to 20_4 are far apart, the difference in the strength of the received signals between the receiving devices 20_1 to 20_4 can be made even greater depending on the position of the detection target. This improves the accuracy with which the position calculation unit 313 calculates the position coordinates of the detection target.

Returning to Figure 2, the determination unit 314 determines whether the smart key 110 and the wireless transmitting tag 111A are present in an area (e.g., area 250) representing the space within the vehicle 10, which is stored in the area information storage unit 322.

For example, the determination unit 314 determines whether the position coordinates of the smart key 110 calculated by the position calculation unit 313 are included in an area representing the inside of the vehicle 10 (e.g., area 250) stored in the area information storage unit 322. Furthermore, if the determination unit 314 determines that the smart key 110 is located in an area representing the inside of the vehicle 10, it may specify whether the smart key 110 is located in an area offset from the inside of the vehicle 10 (e.g., the rear left seat, rear right seat, front left seat, or front right seat).

The determination unit 314 also determines whether the position coordinates of the wireless transmitting tag 111A calculated by the position calculation unit 313 are included in an area representing the inside of the vehicle 10 (e.g., area 250) stored in the area information storage unit 322. Furthermore, if the determination unit 314 determines that the wireless transmitting tag 111A is present in an area representing the inside of the vehicle 10, it may specify in which area inside the vehicle 10 the wireless transmitting tag 111A is present (e.g., rear left seat, rear right seat, front left seat, front right seat).

The output unit 315 performs processing to output (transmit) information to an external device via the wireless communication device 31. When the determination unit 314 determines that there is a left-behind item inside the vehicle 10, the output unit 315 transmits notification information to the mobile communication device 100 via the wireless communication device 31.

For example, if the determination unit 314 determines that the position indicated by the position coordinates of the smart key 110 is not included in the area inside the vehicle 10 (e.g., area 250), but that the position indicated by the wireless transmitting tag 111A is included in the area inside the vehicle 10 (e.g., area 250), the output unit 315 outputs notification information to the mobile communication device 100.

The notification information according to this embodiment may be screen information that can be displayed by the mobile communication device 100, a message on a social networking site, an email, or the like.

In addition, the storage device 302 of the in-vehicle device 30 may store information identifying the detection target (for example, an ID contained in the radio waves) and the name of the detection target in association with each other. For example, the storage device 302 may store an ID identifying the wireless transmitting tag 111A in association with "wallet." As a result, if the determination unit 314 determines that the location coordinates of the wireless transmitting tag 111A are within the interior area of the vehicle 10, even though the location coordinates of the smart key 110 are within the exterior area of the vehicle 10, the output unit 315 can send a message to the mobile communication device 100 as notification information stating, "Your wallet is inside the vehicle, but it has been removed from the vehicle. Please make sure you have not forgotten it."

Furthermore, the output unit 315 may include information regarding the location of the wireless transmitting tag 111A in the notification information. For example, if the determination unit 314 references the area information storage unit 322 and determines that the location coordinates of the wireless transmitting tag 111A are included in the area indicated by "rear left seat" (an example of information regarding the interior position of the vehicle 10), the output unit 315 may send a message to the mobile communication device 100 as notification information stating, "Your wallet is on the rear left seat, but it is away from the vehicle. Please check to make sure you have not forgotten it."

In this embodiment, an example has been described in which the output unit 315 transmits notification information to the mobile communication device 100 via the wireless communication device 31 when it is determined that a lost item exists. However, this embodiment is not limited to an example in which notification information is transmitted to the mobile communication device 100, and notification information may be output using, for example, a speaker or the like provided in the vehicle 10.

Next, we will explain the control flow for reporting when a left-behind item is detected in the in-vehicle device 30 according to this embodiment.

Figure 4 is a flowchart showing the control of the in-vehicle device 30 according to this embodiment regarding notification when it detects a lost item.

The key information acquisition unit 311 acquires information about the smart key 110 (including first signal strength information) from the radio waves received by each of the multiple receiving devices 20_1 to 20_4 (S3001).

The location calculation unit 313 calculates the location coordinates of the smart key 110 based on the first signal strength information (RSSI) acquired by the key information acquisition unit 311 and the antenna information storage unit 321 (S3002).

Next, the tag information acquisition unit 312 acquires information about the wireless transmitting tag 111A from the radio waves received by each of the multiple receiving devices 20_1 to 20_4 (S3003).

The position calculation unit 313 calculates the position coordinates of the wireless transmitting tag 111A based on the second signal strength information (RSSI) acquired by the tag information acquisition unit 312 and the antenna information storage unit 321 (S3004).

The determination unit 314 determines whether the smart key 110 is present in the area representing the inside of the vehicle 10 stored in the area information storage unit 322 (i.e., whether the area 250 includes the position coordinates of the smart key 110) (S3005).

If the determination unit 314 determines that the smart key 110 is not present in the area representing the inside of the vehicle 10 (S3005: NO), it determines whether the wireless transmitting tag 111A is present in the area representing the inside of the vehicle 10 stored in the area information storage unit 322 (whether the area 250 includes the position coordinates of the wireless transmitting tag 111A) (S3006).

If the determination unit 314 determines that the wireless transmitting tag 111A is present in the area representing the inside of the vehicle 10 (S3006: YES), the output unit 315 outputs notification information to the mobile communication device 100 indicating that an object (e.g., a wallet) with the wireless transmitting tag 111A is present in the vehicle 10 (S3007).

On the other hand, if the determination unit 314 determines that the wireless transmitting tag 111A is not present in the area representing the inside of the vehicle 10 (S3006: NO), it recognizes that the user has left the vehicle 10 while carrying the smart key 110 and an object to which the wireless transmitting tag 111A is attached, and terminates the processing.

In S3005, if the determination unit 314 determines that the smart key 110 is present in the area representing the inside of the vehicle 10 (S3005: YES), it determines whether the wireless transmitting tag 111A is present in the area representing the inside of the vehicle 10 stored in the area information storage unit 322 (i.e., whether the area 250 includes the position coordinates of the wireless transmitting tag 111A) (S3008).

If the determination unit 314 determines that the wireless transmitting tag 111A is not present in the area representing the inside of the vehicle 10 (S3008: NO), the output unit 315 outputs notification information to the mobile communication device 100 that the smart key 110 is present in the vehicle 10 (S3009).

On the other hand, if the determination unit 314 determines that the wireless transmitting tag 111A is present in the area representing the space within the vehicle 10 (S3008: YES), it assumes that the user is present in the vehicle 10 and terminates processing.

In this embodiment, by performing the above-described processing, if the user leaves something behind in the vehicle 10, the mobile communication device 100 is notified, allowing the user to be aware of the presence of the item.

(Modification)
In the above-described embodiment, the detection target is the smart key 110 and the wireless transmitting tag 111A. However, the above-described embodiment does not limit the detection target to the smart key 110 and the wireless transmitting tag 111A, but may include any wireless transmitting device capable of transmitting a signal. Therefore, in a modified example, the detection target may include the mobile communication device 100.

In other words, in this modified example, if the in-vehicle device 30 detects that the mobile communication device 100 is outside the vehicle 10 and detects that one or more of the smart key 110 and the wireless transmitting tag 111A of the wallet 111 are inside the vehicle, the in-vehicle device 30 transmits notification information to the mobile communication device 100 indicating that an item has been left behind inside the vehicle 10.

Specifically, the in-vehicle device 30 acquires information about the mobile communication device 100 from the radio waves received by each of the multiple receiving devices 20_1 to 20_4. The position calculation unit 313 then calculates the position coordinates of the mobile communication device 100 from the strength of the signal received by the mobile communication device 100.

If the determination unit 314 determines that the mobile communication device 100 is not present in the area representing the space within the vehicle 10, and that one or more of the smart key 110 and the wireless transmitting tag 111A are present in the area representing the space within the vehicle 10, the output unit 315 transmits notification information to the mobile communication device 100.

In this variant, the user can determine whether or not they have left an item in the vehicle 10 as long as they are carrying at least the mobile communication device 100.

In the above-described embodiment and modified examples, an example in which four receiving devices (including receiving antennas) are provided has been described. However, the above-described embodiment and modified examples are not limited to an example in which four receiving devices (including receiving antennas) are provided. In other words, as long as it is possible to identify the position coordinates of the detection target on at least a two-dimensional coordinate system, for example, three receiving devices may be provided. Furthermore, five or more receiving devices may also be provided.

In the above-described embodiment and variants, when the in-vehicle device 30 determines that one detection target is present outside the vehicle 10 and the other detection target is present in an area inside the vehicle 10, it transmits notification information to the mobile communication device 100. This allows the user to recognize that there is an item left behind in the vehicle 10. In other words, the user can retrieve the item from the vehicle 10. This prevents third parties from retrieving the item, thereby improving safety.

In the above-described embodiment and variants, the radio waves emitted by each detection target include information identifying that detection target. This allows the in-vehicle device 30 to calculate the position coordinates of multiple detection targets.

Instead of the CPU 301, the in-vehicle device 30 may have another processor, or may have an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). In other words, the functions of the in-vehicle device 30 may be realized by hardware. The FPGA or ASIC may also include a communication interface function or an input/output interface function.

In the above-described embodiment, the program executed by the CPU 301 may be stored on a computer-readable recording medium. In this case, the program is downloaded from the recording medium to a memory such as the storage device 302. Examples of recording media include a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a USB (Universal Serial Bus) memory. The program may also be downloaded to at least one of the in-vehicle devices 30 via a network.

The above describes in detail the mode for carrying out the present invention, but the present invention is not limited to such specific embodiments, and various modifications and improvements are possible within the scope of the gist of the present invention.

10 Vehicle 20_1 Right front receiving device 20_2 Left front receiving device 20_3 Right rear receiving device 20_4 Left rear receiving device 25 External bus 30 In-vehicle device 31 Wireless communication device 301 CPU
302 Storage device 303 Input/output I/F
304 RAM
305 In-vehicle communication I/F
306 Internal bus 311 Key information acquisition unit 312 Tag information acquisition unit 313 Position calculation unit 314 Determination unit 315 Output unit 321 Antenna information storage unit 322 Area information storage unit

Claims (1)

a first acquisition unit that acquires, from each of three or more wireless receiving devices provided at positions corresponding to vertices of a rectangle formed by sides in the vehicle's traveling direction and sides in the vehicle's width direction , first signal strength information indicating the strength of a received signal received by the wireless receiving device from a first wireless transmitting device;
a second acquisition unit that acquires, from each of the three or more wireless receiving devices, second signal strength information indicating the strength of a received signal received by the wireless receiving device from a second wireless transmitting device;
a calculation unit that calculates first location information indicating a location where the first wireless transmission device is located based on the first signal strength information, and second location information indicating a location where the second wireless transmission device is located based on the second signal strength information;
An information processing device comprising: an output unit that outputs notification information to a mobile communication device when the position indicated by the first position information is not included in the inner area of the vehicle and the position indicated by the second position information is included in the inner area of the vehicle.