JP7800335B2 - In-vehicle device, notification control method - Google Patents

Description

This disclosure relates to an in-vehicle device and notification control method for providing driving assistance based on information distributed from roadside devices.

Patent Document 1 discloses a system including a roadside unit that distributes assistance information for passing through intersections to vehicles/onboard units. The roadside unit here refers to communication equipment installed along roads that performs road-to-vehicle communication. Roadside units are also sometimes called RSUs (Roadside Units). In addition to wireless equipment for communicating with onboard units, roadside units may also be equipped with monitoring sensors for detecting moving objects.

Assistance information for passing through an intersection includes information about the presence of oncoming vehicles and information indicating the shape of the intersection. When the vehicle-mounted device enters the service area (communication area) of the roadside device, it can receive assistance information from the roadside device and perform driving assistance control such as providing information to the driver and automatic acceleration/deceleration/steering. This configuration can improve safety and driver convenience.

Japanese Patent Application Laid-Open No. 2002-269699

If a roadside unit is installed at an intersection that drivers frequently pass through, it may become commonplace for the driver to receive assistance services from that roadside unit. As a result, when passing through that intersection, the driver may come to perform driving operations that rely on the assistance services provided by that roadside unit.

In the scenario described above, if a malfunction occurs in the roadside unit's radio system, the in-vehicle unit will be unable to receive assistance information and will be unable to provide driving assistance based on the received information. From the driver's perspective, this may feel like the assistance service they regularly use is suddenly no longer available. If a malfunction occurs in a roadside unit like this, it could be confusing for drivers who use that roadside unit on a daily basis.

For these reasons, from one perspective, if an onboard unit detects a malfunction in a roadside unit ahead of the vehicle, it is preferable for the onboard unit to notify the driver of this. On the other hand, even if a malfunction occurs in a roadside unit, the impact will be small for drivers who do not normally use that roadside unit. Drivers are likely to find it annoying to be notified of a malfunction in a roadside unit that they do not normally use.

The present disclosure has been made based on the above considerations and perspectives, and one of its purposes is to provide an in-vehicle device and notification control method that can reduce the risk of annoyance to the driver when notifying the driver of the operating status of a roadside device.

The vehicle-mounted device disclosed herein is configured to receive assistance data, which is data for assisting the vehicle's driving, distributed from each of multiple roadside devices installed along the road. It includes a roadside device detection unit (G31) that detects a forward roadside device that is a roadside device located in front of the vehicle; a roadside device diagnosis unit (G3) that determines whether a malfunction has occurred in the forward roadside device based on the content of a signal received from the forward roadside device, the reception status of a signal from the forward roadside device, or data received from an external device other than the forward roadside device; a recording processing unit (G2) that performs processing to store usage history data, which is data on roadside devices that have been used, in a history storage unit (M1); and a notification control unit (G5) that controls notifications to the driver regarding malfunctions in the forward roadside device, and the notification control unit changes the notification mode to the driver regarding the malfunction in the forward roadside device depending on whether the forward roadside device with the malfunction has been used in the past.

With the above configuration, when a malfunction is detected in the forward roadside unit, a notification of the malfunction is made in a manner that corresponds to the usage history of the forward roadside unit. This reduces the risk of annoyance to the driver when notifying the driver of the operating status of the roadside unit.

The notification control method disclosed herein is a notification control method implemented by at least one processor for notifying a driver of the operating status of a roadside unit that distributes assistance data to assist the vehicle's driving. The notification control method includes the following steps: detecting a forward roadside unit that is located in front of the host vehicle (the vehicle in use by the processor) (S21); storing usage history data, which is data about roadside units that have been used, in a history storage unit (M1) (S12); determining whether a malfunction has occurred in the forward roadside unit based on the content of a signal received from the forward roadside unit, the reception status of a signal from the forward roadside unit, or data received from an external device other than the forward roadside unit (S22); and changing the notification mode to the driver regarding the malfunction in the forward roadside unit depending on whether the forward roadside unit with the malfunction has been used in the past (S24-S28, S34-S39).

The above notification control method corresponds to the above-mentioned vehicle-mounted device and has the same effect as the above-mentioned vehicle-mounted device.

Note that the reference symbols in parentheses in the claims indicate a correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of this disclosure.

FIG. 1 is a diagram for explaining an overall view of a road-to-vehicle communication system. FIG. 2 is a block diagram showing an example of the configuration of an RSU. FIG. 2 is a functional block diagram of an RSU control unit. FIG. 1 is a block diagram showing a configuration of an in-vehicle system. FIG. 2 is a functional block diagram of a control module. FIG. 10 is a diagram showing an example of a warning image. FIG. 10 is a diagram for explaining the operation of the recording processing unit G2. FIG. 10 is a diagram illustrating an example of the contents of RSU data. FIG. 10 is a diagram for explaining the configuration of a malfunction detection message. 10 is a flowchart of a notification control process. FIG. 10 is a diagram illustrating an example of a discreet notification image. FIG. 10 is a diagram illustrating an example of an emphasis notification image. 10 is a flowchart illustrating another example of the notification control process. FIG. 10 is a block diagram showing another example of the configuration of the in-vehicle system.

One embodiment of the road-to-vehicle communication system Sys disclosed herein will be described below with reference to the accompanying drawings. As shown in FIG. 1, the road-to-vehicle communication system Sys includes multiple RSUs (Roadside Units) 1, multiple in-vehicle devices 2, and a management server 3.

RSU1 is a wireless communication device placed along a road and configured to perform short-range communication. In this disclosure, short-range communication refers to communication conducted directly between devices. Short-range communication refers to communication that complies with a specified wireless communication standard, with an effective communication distance of, for example, approximately 150 m or 250 m.

Any standard that can be used for short-range communications is possible, such as DSRC (Dedicated Short Range Communications), which corresponds to the IEEE 802.11p standard, WAVE (Wireless Access in Vehicular Environment), or Cellular V2X (PC5/SideLink). IEEE (registered trademark) is an abbreviation for the Institute of Electrical and Electronics Engineers, a US organization.

Short-range communications can be implemented in accordance with V2X communications standards. V2X stands for Vehicle to X and refers to communications technology that connects vehicles to various things. The first letter "V" in V2X refers to the vehicle/onboard device 2 as the vehicle itself, while "X" can refer to a variety of entities other than the vehicle, such as pedestrians, other vehicles, RSU 1, networks, and servers. "X" can be interpreted as everything/something.

RSU1 is sometimes called a roadside unit. Communication between RSU1 and in-vehicle unit 2 can also be called road-to-vehicle communication or V2I communication. The "I" in V2I stands for Infrastructure and refers to RSU1. In this disclosure, messages (wireless signals) that comply with short-range communication standards are referred to as V2X messages. Additionally, V2X messages sent from RSU1 to in-vehicle unit 2 are also referred to as RSU messages.

The RSU1 distributes assistance data, which is information for assisting driving operations/autonomous driving, to the in-vehicle device 2. Assistance data is, for example, a data set that indicates information about moving objects/obstacles within a specified distance from an intersection, road surface conditions, etc. The assistance data can also be called intersection-related data, as it indicates traffic conditions near the intersection where the RSU1 is installed. The assistance data can also be a data set that indicates traffic conditions near a merging/branching point on a highway. The content of the assistance data can vary depending on the installation location of the RSU1. In this disclosure, a collection of data for multiple items is referred to as a dataset. The term dataset can also be replaced with terms such as data unit, package, message, packet, or frame. In this disclosure, the process of wirelessly distributing assistance data is also referred to as an assistance service.

The RSU 1 communicates with the management server 3, for example, via a WAN (Wide Area Network) 9. The WAN 9 is a TCP (Transmission Control Protocol)/IP (Internet Protocol) network such as the Internet. The WAN 9 may also be other types of communication networks. The RSU 1 may be connected to the management server 3 via a virtual/physical private network/dedicated line. Some RSUs 1 may also be configured to be able to communicate indirectly with the management server 3 via road-to-road communication. Road-to-road communication refers to short-range communication between RSUs 1. The RSU 1 corresponds to a network-connected roadside unit. Note that some RSUs 1 are so-called stand-alone (SA) type RSUs that are not connected to the management server 3.

RSU1 can be placed anywhere along the road. Here, "along the road" includes not only the sides of the road, but also the air above the road surface. RSU1 may also be installed as a marker buried in the road surface.

The RSU 1 may be implemented as a multi-function utility pole equipped with devices such as cameras, sensors, and communication equipment that detect vehicles and pedestrians around the intersection. In one embodiment, the RSU 1 detects pedestrians and vehicles approaching the intersection in real time and transmits data indicating the location of the detected objects to the vehicle-mounted device 2.

A utility pole-type RSU1 may also be called a smart pole or an ITS (Intelligent Transport Systems) pole. Of course, the shape of the RSU1 is not limited to a pole type, and it may also be a box type, a signboard type, or the like. The RSU1 may also be additionally installed on a utility pole, or the like. The RSU1 may also be portable.

Each RSU1 is configured with a monitoring area, which is the range within which objects are detected, and a distribution area, which is the range within which assistance data is distributed. The distribution area can also be called a service area or a service spot. The RSU1 uses a camera 15 (described below) to identify the position, speed, direction of movement, type, etc. of moving objects within the monitoring area. Moving objects include pedestrians, kick scooters, vehicles, etc. Vehicles include bicycles, mopeds, electric kick scooters, motorcycles, etc.

The monitoring area and distribution area may be the same or different. The monitoring area of an RSU1 placed at an intersection can be designed appropriately taking into account the shape of the intersection where the RSU1 is installed. Similarly, the distribution area can be designed according to the characteristics of the location where the RSU1 is installed. For example, an RSU1 placed at an intersection detects moving objects within a specified distance from the intersection and distributes information about the detected moving objects to an in-vehicle unit 2 located within a specified distance from the intersection.

The vehicle-mounted device 2 is a communication device that has the function of conducting wireless communication with other vehicles and the RSU 1. The vehicle-mounted device 2 is installed and used in each of multiple vehicles. The vehicle-mounted device 2 is configured to be capable of short-range communication with other vehicle-mounted devices 2 and the RSU 1. While Figure 1 shows only one vehicle equipped with the vehicle-mounted device 2, there may actually be two or more vehicles in the entire system. In this disclosure, for a certain vehicle-mounted device 2, the vehicle in which the vehicle-mounted device 2 is installed is also referred to as the vehicle itself, and vehicles other than the vehicle itself are also referred to as other vehicles.

Furthermore, in this disclosure, the vehicle-mounted device 2 itself will be referred to as the "own device" to distinguish it from other vehicle-mounted devices 2, and the vehicle-mounted device 2 used in another vehicle will be referred to as the "other device." Because there is a one-to-one relationship between the vehicle and the vehicle-mounted device 2, the term "vehicle" as the source/destination of a wireless signal/data/packet can be read as "vehicle device." Therefore, the terms "own device" and "other device" in the following description can also be interpreted as "own vehicle" and "other vehicle."

Each vehicle-mounted device 2 periodically transmits a vehicle status message indicating information about the vehicle via short-range communication. For example, each vehicle-mounted device 2 may periodically transmit a vehicle status message indicating sender information, transmission time, current location, direction of travel, driving speed, acceleration, steering angle, and blinker/wiper operation status. The message transmitted by the vehicle-mounted device 2 may be a CAM (Cooperative Awareness Message) defined in ETSI standard TS 102 637-2 or a BSM (Basic Safety Message) defined in SAE standard J 2735. Each message may include information indicating the transmission time.

Furthermore, each vehicle-mounted device 2 may transmit a message indicating information about the surrounding environment when a specific event is detected. The message transmitted by the vehicle-mounted device 2 may be an event message such as the Decentralized Environmental Notification Message (DENM) defined in the ETSI standard TS 102 637-3.

The management server 3 is a device that manages the RSU 1. The management server 3 can diagnose whether the RSU 1 is operating normally by communicating bidirectionally with the RSU 1, for example, via the WAN 9. Diagnostic methods include the watchdog timer method and the homework answer method. The watchdog timer method determines that a malfunction has occurred in the monitored device if the watchdog timer of the monitoring device expires without being cleared by a watchdog pulse input from the monitored device. The homework answer method determines whether the monitoring device is operating normally based on whether the answer returned from the monitored device is correct. In the homework answer method, the monitored device generates a response signal in response to the monitoring signal input from the monitoring device and returns it to the monitoring device. Here, the management server 3 corresponds to the monitoring device, and the RSU 1 corresponds to the monitored device.

Each RSU 1 may be equipped with a self-diagnosis function, as described below. For an RSU 1, the management server 3 may recognize the status of the reporting source by receiving the self-diagnosis results reported from that RSU 1. The management server 3 may also recognize the status of the RSU 1 based on reports from the vehicle-mounted device 2.

The status of RSU1 indicates whether it is operating normally or whether a malfunction has occurred in some of its functions. The status of RSU1 can be classified into five patterns, for example: (A) normal, (B) camera malfunction, (C) GNSS malfunction, (D) radar malfunction, and (E) other malfunction. Note that a malfunction here refers to an abnormal state. A malfunction can also be referred to as a breakdown, failure, or abnormality.

"Camera malfunction" means that there is a malfunction in the camera equipped in RSU1. "GNSS malfunction" means that there is a malfunction in the GNSS receiver equipped in RSU1. GNSS stands for Global Navigation Satellite System and refers to a global positioning satellite system. Possible GNSSs include GPS (Global Positioning System), GLONASS, Galileo, IRNSS, QZSS, and Beidou.

"Radar malfunction" means that there is a malfunction in the millimeter-wave radar/LiDAR equipped in RSU1. LiDAR is an abbreviation for Light Detection and Ranging or Laser Imaging Detection and Ranging. The concept of LiDAR can include a ToF (Time of Flight) camera that generates distance images using the round-trip time of light. Note that malfunctions with ToF cameras may be classified as camera malfunctions. "Other malfunctions" refers to malfunctions in areas other than those listed above, or malfunctions of unknown cause. A separate category for "unknown cause" may be prepared in addition to "other malfunctions."

The status of RSU1 may be categorized into "sonar failure," which indicates a sonar malfunction, and "jamming detected," which indicates that the device is being jammed. Furthermore, if various types of cameras are expected, such as color cameras, infrared cameras, and Time of Flight cameras, "camera failure" may be further subdivided according to the type. The status of RSU1 may be evaluated in two stages: normal/failure. The status of RSU1 may be expressed using a predetermined number of bit strings/codes.

When the management server 3 detects a malfunction in a certain RSU 1, it may notify an operator using a display, speaker, etc. An operator refers to a staff member engaged in work related to the OAM (Operation, Administration, and Maintenance) of the RSU 1. The management server 3 may also distribute information about the malfunctioning RSU 1 to an in-vehicle unit 2 moving toward that RSU 1. Information distribution to the in-vehicle unit 2 may be performed via road-to-vehicle communication using another RSU 1, or via cellular communication. The in-vehicle unit 2 may obtain information about the malfunctioning RSU 1 from the management server 3.

<Configuration and functions of RSU>
Here, we will explain the configuration and functions of the RSU 1. As shown in Figure 2, the RSU 1 includes an RSU control unit 11, a radio unit 12, a GNSS receiver 13, a millimeter-wave radar 14, a camera 15, an image analysis unit 16, and a WAN module 17.

The RSU control unit 11 is a module that controls the overall operation of the RSU 1. The RSU control unit 11 is configured to be able to communicate with each of the radio units 12 and others. The RSU control unit 11 is configured as a computer that includes, for example, a processor 111, memory 112, storage 113, and input/output (I/O) circuitry 114. The processor 111 is, for example, a CPU (Central Processing Unit). The memory 112 is, for example, a volatile storage medium such as RAM (Random Access Memory). The processor 111 accesses the memory 112 to perform various processes to realize the functions of each functional unit, described below. The storage 113 is configured to include a non-volatile storage medium such as flash memory. The storage 113 stores RSU programs, which are programs for realizing various functions/services. The input/output circuitry 114 is a circuit module that allows the RSU control unit 11 to send and receive signals with other devices.

In this disclosure, the RSU 1 that the RSU control unit 11 houses itself is also referred to as its own unit/belonging unit. Additionally, RSUs 1 other than the belonging unit are also referred to as other units. The functions of the RSU control unit 11 will be described later.

The radio unit 12 is a communication module for performing short-range communication. The radio unit 12 includes an antenna, a transmission processing unit, and a reception processing unit. The antenna is used to transmit and receive radio waves in the frequency band used for short-range communication. The transmission processing unit modulates data input from the RSU control unit 11 and outputs it to the antenna for wireless transmission. The reception processing unit demodulates signals received by the antenna and outputs them to the RSU control unit 11.

The GNSS receiver 13 is a device that sequentially calculates its current position (e.g., every 100 milliseconds) by receiving navigation signals transmitted from positioning satellites that make up the GNSS. The current position data can be expressed as latitude, longitude, altitude, etc. The GNSS receiver 13 transmits the calculated position data to the RSU control unit 11.

The GNSS receiver 13 also determines the current time based on the time information contained in the navigation signal and outputs it to the RSU control unit 11. For example, the GNSS receiver 13 may calculate the current time based on time error information determined during position calculation and output it to the RSU control unit 11.

The millimeter-wave radar 14 obtains information about objects present in the monitoring area by transmitting and receiving millimeter waves or quasi-millimeter waves. Specifically, it detects objects present in the monitoring area and estimates the direction, distance, relative speed, type, etc. of the detected object. The millimeter-wave radar 14 outputs radar detection data to the RSU 11 indicating the position, type, direction of movement, speed, etc. of each detected object.

Camera 15 is an optical camera configured to capture the entire monitoring area. Camera 15 may also be an infrared camera. The image data generated by camera 15 is input to image analysis unit 16. The term "image data" used here may also be interpreted as a video signal.

The image analysis unit 16 detects moving objects within the monitoring area by analyzing images generated by the camera 15. The image analysis unit 16 may be configured to detect not only moving objects, but also obstacles that affect vehicle travel. Obstacles include, for example, road construction signs, cones, puddles, snow-covered areas, and fallen objects. The image analysis unit 16 outputs camera detection data, which is a data set indicating the positions of moving objects/obstacles detected by analyzing the camera images, to the RSU 11. The camera detection data may include the position, type, direction of movement, and speed of each detected object. The functionality of the image analysis unit 16 may be built into the camera 16/RSU control unit 11.

The millimeter-wave radar 14 and camera 15 are examples of area monitoring sensors for detecting traffic conditions within a monitoring area. The RSU 1 may be equipped with multiple millimeter-wave radars 14 and multiple cameras 15. The RSU 1 may also be equipped with sonar, LiDAR, or other area monitoring sensors. The millimeter-wave radar 14 and camera 15 are not essential elements for the RSU 1 and may be omitted. The combination of area monitoring sensors equipped in the RSU 1 can be changed as appropriate.

The WAN module 17 is a communications module that connects the RSU 1 to the WAN 9. The WAN module 17 receives data from the management server 3 and outputs it to the RSU control unit 11, and also modulates data input from the RSU control unit 11 and transmits it to the management server 3. The RSU 1 may be connected to the WAN 9 via a wired or wireless connection. That is, the WAN module 17 may be a signal processing module that includes a connector for a wired connection, or a wireless module for cellular communication. In this disclosure, cellular communication refers to wireless communication that uses mobile phone lines provided by mobile communication carriers, such as LTE (Long Term Evolution), 4G, and 5G.

The RSU control unit 11 includes a support information distribution unit F1, a self-diagnosis unit F2, and a status notification unit F3, as functional units that are activated when the processor 111 executes the RSU program stored in the storage 113, as shown in FIG. 3.

The support information distribution unit F1 generates support data indicating traffic conditions within a monitoring area, for example, based on output data from an area monitoring sensor. Output data from an area monitoring sensor may include radar detection data, camera detection data, image data, etc. The support information distribution unit F1 may combine output data from multiple area monitoring sensors to detect traffic conditions within the monitoring area.

The assistance information distribution unit F1 also wirelessly transmits assistance data generated based on data from the area monitoring sensors to the in-vehicle device 2 in cooperation with the wireless unit 12. In this disclosure, the wireless signal/electrical signal equivalent to a communication packet containing assistance data is also referred to as an assistance message. In this disclosure, the term "assistance data" can be interpreted as an assistance message as appropriate. An assistance message corresponds to a MAP message, which is one type of RSU message.

The RSU1 broadcasts support messages. The support message generation/transmission period by the support information distribution unit F1 can be limited to approximately once every 100 milliseconds to 1 second.

The RSU 1 may distribute the assistance message in the form of unicast, multicast, or geocast. Geocast is a flooding communication method that specifies the destination using location information. With geocast, vehicle-mounted units 2 located within a range designated as the geocast area can receive the message. Geocasting makes it possible to distribute data without specifying the identification information of vehicle-mounted units 2 located in the area to which the information is to be distributed.

The RSU 1 may also be configured to periodically send advertising messages in addition to assistance messages. Advertising messages are messages for notifying the vehicle-mounted device 2 of the presence of the RSU 1, and indicate the RSU-ID, installation location, transmission time, service type, RSU type, etc. Advertising messages may be simple messages that focus on the contents of the header described above. Advertising messages can also be called service announcements, which are messages for notifying surrounding areas of the services provided by the RSU 1.

The self-diagnosis unit F2 is a functional unit that diagnoses whether its associated unit is functioning normally. It is configured to be able to perform either image-based diagnostic processing or time-based diagnostic processing, or both, as self-diagnosis processing. Details of the self-diagnosis unit F2 will be described separately below.

If the self-diagnosis unit F2 determines that a malfunction has occurred in its own unit, it may identify the location of the malfunction. The self-diagnosis unit F2 may be configured to identify whether the malfunction has occurred in, for example, the radio unit 12, the GNSS receiver 13, the millimeter-wave radar 14, the camera 15, or the RSU control unit 11. In other words, the self-diagnosis unit F2 may determine whether each of the devices that make up its own unit is functioning normally.

The status notification unit F3 is configured to notify the vehicle-mounted device 2, management server 3, and other RSUs 1 of the diagnostic results of the self-diagnosis unit F2. For example, the status notification unit F3 periodically transmits, from the wireless unit 12, a support message whose header contains a status code corresponding to the diagnostic result. This allows the vehicle-mounted device 2 to recognize the status of the RSU 1 that sent the support message based on the received support message.

In addition, RSU1 may send a dedicated message to notify the status of its own unit, separate from the assistance message. In this disclosure, an RSU message containing data indicating the status of RSU1 is also referred to as a status message. Among status messages, an RSU message containing a code indicating a malfunction is also referred to as a malfunction notification message, and an RSU message containing a code indicating normal operation is also referred to as a normal operation notification message. RSU1 may make an advertisement message function as a status message by inserting a status code into a specified field of the advertisement message, for example, an options field.

The status message must contain at least the RSU-ID, transmission time, and status code in the header or payload. The RSU-ID is the identification number (ID) of the RSU1 as the sender. The transmission time indicates the time the message was sent. The status code is a code that indicates the status of the sender. The status message may also include information such as the installation location, target area, and message size. The target area indicates the area to which RSU1 provides services, i.e., the distribution area. The target area can be expressed, for example, by the location coordinates of the area center and the area radius. The target area may also be expressed only by the distance (radius) from the RSU installation location.

The status notification unit F3 may omit sending a status message if the unit is operating normally. The status notification unit F3 may also be configured to send a malfunction notification message to the vehicle-mounted unit 2 only if a malfunction is detected in its own unit. This configuration reduces the risk of inadvertently consuming short-range communication resources.

In this embodiment, the RSU1 not only notifies the user that a malfunction has occurred, but also sends a malfunction notification message indicating the details of the malfunction, i.e., the location of the malfunction. In another embodiment, the malfunction notification message may be a message indicating that some kind of malfunction has occurred in the RSU1. The malfunction notification message may simply be a message indicating that service is currently suspended. The status notification unit F3 may transmit self-diagnosis results and data related to moving objects/obstacles within the monitoring area to the management server 3 periodically or in response to an inquiry from the management server 3.

<About image-based diagnostic processing>
The image-based diagnostic process is a process for determining the operating state of the camera 15 by comparing a current camera image with a camera image captured in the past. The image-based diagnostic process requires a reference image registration process as a preparatory process. The reference image registration process is a process for generating a reference image as a criterion for verifying whether the camera 15 (e.g., an image sensor) is functioning normally and registering the reference image in the storage 113.

A reference image is image data of fixed and stationary objects, with moving objects such as cars and pedestrians removed from the image captured by camera 15. A reference image can also be called a fixed image. A reference image may be generated by combining multiple camera images captured at different times. By generating a comparison image based on multiple images captured at different times (frames), a road surface image of an area in which a moving object was captured in a certain frame can be supplemented with an image from another frame. This reference image registration process can be triggered by a specific operation by the installer, such as pressing the record button, when installing RSU1. The reference image registration process may also be performed periodically, such as once a month.

Image-based diagnostic processing includes a step of generating a comparison image based on the current image, which is the most recent image generated by camera 15. The comparison image is an image from which moving objects have been removed, in other words, an image from which areas containing fixed/still objects have been extracted from the current image. The comparison image may also be generated by combining multiple images captured within a certain period of time. Self-diagnosis unit F2 compares the comparison image with a reference image registered in storage 113, and if the difference between them is equal to or greater than a predetermined value, self-diagnosis unit F2 determines that a malfunction has occurred in camera 15/its own unit.

The time-based diagnostic process determines whether the GNSS receiver 13 is operating normally by comparing the time information received from the vehicle-mounted device 2 with the time information held by the unit itself. The time-based diagnostic process can be performed at regular intervals. If a malfunction occurs in the GNSS receiver 13, the error between the internal time, which is the time information held by the RSU control unit 11, and the actual time may exceed a predetermined value. The internal time of the RSU 1 can also be called the RSU time.

The time-based diagnostic process may include a step of calculating the average time, which is the average value of the vehicle time information contained in messages received from the vehicle-mounted unit 2 within a fixed time period (e.g., 200 milliseconds), as a population. The vehicle time information is the time information contained in messages received from the vehicle-mounted unit 2. The average time corresponds to the average value of the times held by multiple vehicle-mounted units 2 present within the communication area of the RSU1. If the difference between the internal time and the average time is equal to or greater than a specified value, the self-diagnosis unit F2 determines that a malfunction has occurred in the GNSS receiver 13/its own unit.

In addition, the self-diagnosis unit F2 may diagnose the millimeter-wave radar 14 by comparing the detection results of the millimeter-wave radar 14 with information about moving objects/obstacles within the intersection received from the vehicle-mounted unit 2. The self-diagnosis unit F2 may also diagnose the camera 15 or the millimeter-wave radar 14 by comparing camera detection data with radar detection data. For example, the self-diagnosis unit F2 may detect a malfunction of the millimeter-wave radar 14 based on the fact that something detected by the camera 15 is not detected by the millimeter-wave radar 14. Similarly, the self-diagnosis unit F2 may detect a malfunction of the camera 15 based on the fact that something detected by the millimeter-wave radar 14 is not detected by the camera 15.

The self-diagnosis unit F2 may also detect a malfunction of the radio unit 12 based on whether the noise level observed by the radio unit 12 remains above a predetermined value for a predetermined period of time. A malfunction of the radio unit 12 may include a malfunction in the radio unit 12 itself, as well as a malfunction when jamming radio waves are being received.

The self-diagnosis unit F2 may detect a malfunction of the GNSS receiver 13 by comparing the registered installation position, which is the installation position coordinates registered in advance by the administrator/installer, with the latest positioning calculation result input from the GNSS receiver 13. For example, if the difference between the registered installation position and the positioning calculation result is equal to or greater than a predetermined value, it may determine that a malfunction has occurred in the GNSS receiver 13. It may also determine that a malfunction has occurred in the GNSS receiver 13 based on the fact that current position data has not been input from the GNSS receiver 13 for a certain period of time (e.g., one hour).

Furthermore, the self-diagnosis unit F2 may detect malfunctions in the RSU control unit 11 or the communication partner by performing two-way communication with the microcomputers provided in the wireless unit 12 and image analysis unit 16. Methods for detecting malfunctions via two-way communication include a watchdog timer method and a homework answer method.

<Configuration and functions of the in-vehicle device>
As shown in FIG. 4 , the in-vehicle device 2 is connected to a locator 41, a perimeter monitoring sensor 42, a vehicle sensor 43, a cellular communication unit 44, a display 45, a speaker 46, and a drive system 47 via an in-vehicle network VN so that they can communicate with each other. Various standards, such as Controller Area Network (CAN: registered trademark), Ethernet (registered trademark), and FlexRay (registered trademark), can be adopted for the in-vehicle network VN. Note that some devices may be directly connected to the in-vehicle device 2 via dedicated cables. The connection between devices shown in this disclosure is merely an example, and the specific connection between devices can be changed as appropriate. In this disclosure, a system including various devices mounted on a vehicle, including the in-vehicle device 2, is also referred to as an in-vehicle system VS. The in-vehicle device 2 includes a V2X module 21 and a control module 22.

The V2X module 21 is a communications module for performing short-range communications. Similar to the radio unit 12, the V2X module 21 includes an antenna, a transmission processing unit, and a reception processing unit for performing short-range communications. The V2X module 21 is connected to the control module 22. The V2X module 21 transmits radio signals obtained by performing signal processing such as modulation on baseband signals input from the control module 22. The V2X module 21 also outputs received data to the control module 22 by performing signal processing such as demodulation on signals received via the antenna. For example, the V2X module 21 receives assistance messages/data distributed from the RSU 1 and inputs the data to the control module 22.

The control module 22 is configured as a computer including a processor 221, memory 222, storage 223, input/output circuit (I/O) 224, etc. The processor 221 is, for example, a CPU. The memory 222 is, for example, a volatile storage medium such as RAM. The processor 221 accesses the memory 222 to execute various processes to realize the functions of each functional unit described below. The storage 223 is configured to include a non-volatile storage medium such as flash memory. A vehicle program, which is a program for the vehicle-mounted device 2, is stored in the storage 223. Execution of the vehicle program by the processor 221 corresponds to execution of a notification control method. The storage 223 corresponds to a memory unit. The input/output circuit 224 is a circuit module that enables the vehicle-mounted device 2 to send and receive signals to and from other devices. The functions of the control module 22, in other words, the functions of the vehicle-mounted device 2, will be described separately below.

In this embodiment, the V2X module 21 and the control module 22 are implemented as a single device (ECU: Electronic Control Unit), but this is not limited to this. The V2X module 21 and the control module 22 may be separated into separate devices. For example, the V2X module 21 may be implemented as a V2X in-vehicle device, and the control module 22 may be implemented as a driving assistance ECU, each implemented separately.

The locator 41 is a device that calculates and outputs the position coordinates of the vehicle using navigation signals transmitted from positioning satellites that make up the GNSS. The locator 41 includes, for example, a GNSS receiver, an inertial sensor, and a map memory. The inertial sensor is, for example, a gyro sensor or an acceleration sensor. The map memory is a storage medium in which map data is saved. The locator 41 sequentially determines the position of the vehicle (hereinafter referred to as the vehicle position) and direction of movement of the vehicle equipped with the locator 41 by combining the positioning signals received by the GNSS receiver, the detection values of the inertial sensor, and the road shape shown in the map data. The vehicle position is expressed, for example, in three-dimensional coordinates of latitude, longitude, and altitude. The vehicle position data detected by the locator 41 is input to the vehicle-mounted device 2. The locator 41 may also be a navigation device.

The perimeter monitoring sensor 42 outputs a signal indicating the environment surrounding the vehicle. Examples of perimeter monitoring sensors 42 include cameras that capture images outside the vehicle, millimeter-wave radar, LiDAR, and sonar. The perimeter monitoring sensor 42 detects objects within a detection range around the vehicle and inputs data indicating the position, movement speed, type, size, etc. of the detected object to the in-vehicle device 2. For example, the in-vehicle system VS includes a forward-facing camera and forward-facing radar as the perimeter monitoring sensor 42. The forward-facing camera is, for example, an optical/infrared camera positioned to capture images in front of the vehicle at a predetermined angle of view. The forward-facing camera is positioned on the upper edge of the windshield facing the interior of the vehicle, the front grille, the rooftop, etc. The forward-facing radar is a millimeter-wave radar installed on the front of the vehicle, such as the front grille or front bumper. The forward-facing radar detects the distance, relative speed, relative position, size, etc. of objects in front of the vehicle, such as a preceding vehicle.

The vehicle sensors 43 are a group of sensors that detect information related to the state of the host vehicle. The vehicle sensors 43 include a vehicle speed sensor, steering angle sensor, acceleration sensor, yaw rate sensor, etc. The vehicle speed sensor detects the speed of the host vehicle. The steering angle sensor detects the steering angle. The acceleration sensor detects acceleration such as longitudinal acceleration and lateral acceleration of the host vehicle. The yaw rate sensor detects the angular velocity of the host vehicle. The vehicle sensors 43 input data indicating the current value of the physical state quantity to be detected (i.e., the detection result) to the in-vehicle device 2. The types of vehicle sensors 43 connected to the in-vehicle device 2 may be designed as appropriate. It is not necessary for signals from all of the sensors described above to be input to the in-vehicle device 2. A signal indicating the gear position or the operation status of the turn signal may also be input to the in-vehicle device 2.

The cellular communication unit 44 is a communication module for implementing cellular communication. For example, the cellular communication unit 44 transmits and receives radio waves to and from base stations around the vehicle via wireless communication conforming to cellular communication standards such as 5G. The cellular communication unit 44 transmits data input from the onboard unit 2 to the management server 3. The cellular communication unit 44 also receives data addressed to the onboard unit 2 from the management server 3 and inputs the data to the onboard unit 2.

The display 45 is, for example, a liquid crystal display or an organic EL display. The display 45 may also be a head-up display. The in-vehicle system VS may be equipped with a meter display and a head-up display (HUD) as displays. At least one display 45 displays an image corresponding to an input signal from the in-vehicle device 2. The speaker 46 is a device that converts an electrical signal into sound and outputs the sound. The speaker 46 outputs sound corresponding to the electrical signal input from the in-vehicle device 2. Sounds in the present disclosure include voice messages, notification sounds, warning sounds, sound effects, music, etc.

The drive system 47 is a system that includes actuators for driving the vehicle and ECUs for controlling them. The components of the drive system 47 may include some or all of the following: a power unit ECU that controls drive sources such as the engine and traction motor, a brake actuator, a brake ECU, an EPS (Electric Power Steering) motor, and a steering ECU.

As shown in FIG. 5, the control module 22 includes functional units realized by the processor 221 executing the vehicle program: a support processing unit G1, a recording processing unit G2, an RSU diagnosis unit G3, a communication processing unit G4, and a notification control unit G5. The RSU diagnosis unit G3 includes an RSU detection unit G31 as a sub-functional unit.

The support processing unit G1 provides driving support based on the support data received from the RSU1. For example, the support processing unit G1 notifies the driver of other moving objects approaching the vehicle within an intersection. More specific examples include notifying the driver of the presence of pedestrians or cyclists who may be in contact with the vehicle, or notifying the driver of the presence of oncoming vehicles when turning right. Furthermore, at intersections without traffic lights, the support processing unit G1 may also notify the driver of the presence of vehicles approaching from the right or left based on a support message from the RSU1.

Notification of assistance information to the driver can be achieved by displaying an image on the display 45, outputting a voice message/warning sound from the speaker 46, lighting up an indicator, applying vibrations, etc. The device that generates the vibrations may be provided in a location that the driver's body comes into contact with, such as the seat, seat belt, or steering wheel.

For example, if the support processing unit G1 detects another moving object that may be in contact with the vehicle based on a message from RSU1, it will sound an alarm and display a warning image Im1 on the display 45. Figure 6 shows an example of the warning image Im1. 45a in the figure indicates the display screen/display area of the display.

When the vehicle-mounted device 2 is able to receive a signal from the RSU1, the notification control unit G5 displays a service-in image Im2 at a predetermined position on the display 45. The service-in image Im2 is an icon image indicating that data is being received from the RSU1. The service-in image Im2 can be, for example, an image in which a radio wave icon, an element that resembles radio waves, is placed near an RSU icon, an element that resembles the RSU1.

The driving assistance processing performed by the assistance processing unit G1 may not only notify the driver, but may also include control that intervenes in driving operations such as braking and steering. In this disclosure, the term "driver" refers to the person sitting in the driver's seat, i.e., the driver's seat occupant. The concept of driver can also include a person remotely operating the vehicle.

As shown in FIG. 7, when the recording processing unit G2 receives an RSU message (S11), it stores data related to the sender RSU1 in the history memory unit M1 of storage 223 (S12). In this disclosure, the list of RSU1s that have received messages is referred to as usage history data. The history memory unit M1 is a storage area for storing usage history data. The storage area for the history memory unit M1 may be allocated dynamically, or may be allocated in advance with a predetermined size. The history memory unit M1 may be implemented using a storage device independent of storage 223.

The usage history data includes RSU data, which is detailed data for each RSU1. For example, as shown in FIG. 8, each RSU data may include the installation location, RSU-ID, number of uses, number of warnings, number of interventions, distribution area, etc. The number of uses may include the number of times the service provided by the RSU1 has been used. The number of uses may correspond to the number of times a distribution area has been passed through. The number of uses can also be referred to as the number of times an area has been passed through, or the number of times an assistance message has been received. Using an RSU1 may correspond to receiving an assistance message distributed from the RSU1.

The number of warnings refers to the number of times that warning processing has been performed based on a received assistance message. Warning processing corresponds to, for example, notifying the driver of the presence of a moving object that may come into contact with the vehicle using the display 45, speaker 46, vibrator, etc. The conditions for performing warning processing can be designed as appropriate.

The number of interventions refers to the number of times an operation intervention process has been performed based on a received assistance message. An operation intervention process refers to automatic vehicle control by the system, for example, to avoid contact between the vehicle and a moving object or to reduce the damage of a collision. An example of an operation intervention process is automatic braking. An operation intervention process may include steering control in a direction to avoid a collision. An operation intervention process can also be called collision damage reduction control/collision avoidance control. The conditions for performing an operation intervention process can be designed as appropriate. For example, it can be performed when there is a moving object whose remaining time to collision (TTC: Time To Collision) is less than a predetermined value.

The above usage history data may correspond to data mapping RSU1s that the vehicle-mounted device 2 has used. The recording processing unit G2 updates the usage history data as it receives an RSU message. For example, if it receives an RSU message from an RSU1 that has never been used before, it adds information about that RSU1 to the usage history data. When the size of the usage history data exceeds a predetermined value, the recording processing unit G2 prioritizes retaining data about RSU1s that have been used frequently. In other words, when the storage capacity is full, the recording processing unit G2 prioritizes deleting data about RSU1s that have been used least frequently.

It is preferable that the recording processing unit G2 only increases the number of times the RSU 1 is used by 1 even if it receives multiple RSU messages from the same RSU 1 within a predetermined time period (e.g., 5 minutes). This control reduces the risk of the number of times the RSU 1 is used increasing by 2 or more, even if it receives multiple messages from the same RSU 1 while waiting at a traffic light, etc.

Furthermore, the recording processing unit G2 does not need to record all of the number of uses, number of warnings, and number of interventions. The RSU data does not need to include the number of warnings or number of interventions. In addition, the RSU data may include data indicating the observed value of the reception strength according to the distance from RSU1. For example, the recording processing unit G2 may record the reception strength at points where the remaining distance to RSU1 is 25 m, 15 m, and 5 m. Furthermore, the usage history data may also include farthest reception position information. The farthest reception position information is the coordinates of the position where a message from RSU1 could be received furthest.

The RSU diagnostic unit G3 determines whether the RSU 1 located ahead of the host vehicle is operating normally. The RSU diagnostic unit G3 corresponds to the roadside unit diagnostic unit. The RSU 1 located ahead of the host vehicle refers to an RSU 1 located ahead of the host vehicle and in a position where short-range communication with the host vehicle is possible. This also includes an RSU located diagonally ahead of the host vehicle. Hereinafter, the RSU 1 that the RSU diagnostic unit G3 targets for diagnosis will also be referred to as the target RSU. The target RSU can also be referred to as the forward RSU (forward roadside unit) or the communication partner. The forward RSU/target RSU can also be interpreted as the RSU 1 installed in a road section that the host vehicle will pass through within a specified time. For example, the RSU 1 installed at an intersection ahead of the host vehicle corresponds to the target RSU.

The RSU diagnosis unit G3 may recognize the presence of the target RSU by receiving an RSU message. The RSU diagnosis unit G3 may also detect the target RSU based on map data showing the installation location of RSU1. The RSU diagnosis unit G3 may also detect the target RSU based on usage history data. The configuration that detects the forward RSU as the diagnosis target based on map data/reception of V2I messages/usage history data corresponds to the RSU detection unit G31 (roadside unit detection unit). The RSU diagnosis unit G3 corresponds to the malfunction detection unit.

The RSU diagnostic unit G3 can diagnose the target RSU using a variety of methods. The RSU diagnostic unit G3 may diagnose the target RSU based on data included in a message received from the target RSU. For example, the RSU diagnostic unit G3 may determine that a malfunction has occurred in the target RSU based on the difference between the time information included in the message received from the target RSU and the time held by the RSU diagnostic unit G3 being equal to or greater than a predetermined value. Diagnosis based on this difference in time information corresponds to the time-based diagnostic processing described above. The RSU diagnostic unit G3 may also determine that a malfunction has occurred in the target RSU based on the difference between the installation location information included in the message received from the target RSU and the location of the target RSU recognized by the vehicle being equal to or greater than a predetermined value. Furthermore, the RSU diagnostic unit G3 may determine that a malfunction has occurred in the target RSU if the security information in the received RSU message is inappropriate. Examples of cases where the security information is inappropriate include when an electronic certificate is not assigned or when the electronic certificate has expired.

Furthermore, for an RSU1 with a usage history, the RSU diagnostic unit G3 may compare past reception conditions with current reception conditions to determine whether the target RSU is functioning normally. For example, the RSU diagnostic unit G3 may estimate the communication area of the target RSU based on a set of locations where messages from the target RSU have been received in the past. Then, if the vehicle is located within that communication area but is unable to receive a message from the target RSU, it may determine that a malfunction has occurred in the target RSU.

Furthermore, for an RSU1 with a usage history, the RSU diagnostic unit G3 determines whether the vehicle is located within the distribution area of the target RSU based on distribution area information acquired during past use. If the vehicle is located within the distribution area of the target RSU but is unable to receive a message from the target RSU, it may determine that a malfunction has occurred in the target RSU. This corresponds to reception status-based diagnostic processing (determination processing) that diagnoses the target RSU based on the reception status of messages from the target RSU.

Note that if a large vehicle such as a truck is present in front of the vehicle, it may be difficult to receive messages from the target RSU. Therefore, if a forward camera or the like detects that a large vehicle is present within a predetermined distance in front of the vehicle, the RSU diagnostic unit G3 may cancel the implementation of the reception status-based diagnostic process. In other words, it is preferable that the reception status-based diagnostic process be implemented on the condition that no large vehicle is present within a predetermined distance in front of the vehicle. This configuration reduces the risk of erroneously determining that a malfunction has occurred in an RSU 1 that is operating normally. Note that a large vehicle may be a vehicle with a height of a predetermined value (e.g., 3 m) or more. Whether a vehicle is a large vehicle or not may be defined by vehicle classification prescribed by law.

The RSU diagnostic unit G3 may determine whether the target RSU is operating normally by comparing the detection results of the vehicle's perimeter monitoring sensor 42 with the location information of the moving object notified by the target RSU. The RSU diagnostic unit G3 may determine that a malfunction has occurred in the target RSU based on the detection of a moving object by the vehicle's perimeter monitoring sensor 42 that has not been notified by the target RSU. In addition, the RSU diagnostic unit G3 may determine whether the target RSU is operating normally by comparing the location information of the moving object obtained from another vehicle via vehicle-to-vehicle communication with the location information of the moving object obtained from the target RSU.

The RSU diagnosis unit G3 may determine that a malfunction has occurred in the target RSU based on receiving a malfunction notification message from the target RSU. This configuration also corresponds to a configuration that detects a malfunction in a forward RSU based on data received from the forward RSU.

Furthermore, the RSU diagnostic unit G3 may determine that a malfunction has occurred in the front RSU based on receiving data indicating that a malfunction has occurred in the front RSU from an external device such as another in-vehicle unit 2 or the management server 3. The RSU diagnostic unit G3 may confirm the determination that a malfunction has occurred in the target RSU if it receives information from the target RSU itself that a malfunction is occurring and the RSU diagnostic unit G3 itself determines that a malfunction has occurred in the target RSU. One or more of the various methods described above can be used as an RSU diagnosis method by the in-vehicle unit 2.

The communication processing unit G4 controls data communication with the management server 3, the RSU 1, and other onboard devices 2. For example, when the RSU diagnosis unit G3 detects a malfunction in the RSU 1, the communication processing unit G4 sends a malfunction detection report to the management server 3 as a reporting process. The malfunction detection report is a communication packet indicating that the target RSU may not be functioning normally. The communication processing unit G4 corresponds to the report processing unit.

As shown in Figure 9, a malfunction detection report includes source information, the identification number (RSU-ID) of the RSU 1 to be reported, and the time the malfunction was detected. The malfunction detection report may also include some or all of the installation location of the RSU 1 to be reported, a status code, and an environmental code. Each piece of data may be written in the header, or some or all of the data may be stored in the payload section. The source information may be expressed, for example, as a vehicle ID/MAC address/IP address of the onboard unit 2. The environmental code is information indicating the surrounding environment when the status of the RSU 1 is determined, such as the presence or absence of a preceding vehicle, the type of preceding vehicle (large or not), and the weather. D21 to D26 in Figure 9 represent data fields in which various data are placed in the message/communication packet that serves as the malfunction detection report.

The malfunction detection report may be sent to the management server 3 via cellular communication. Alternatively, the malfunction detection report may be transmitted to the management server 3 via the RSU 1. Each RSU 1 may forward the malfunction detection report received from the vehicle-mounted device 2 to the management server 3.

The communication processing unit G4 may also transmit a malfunction detection message, which is a V2X message containing the same content as a malfunction detection report, to another device via short-range communication. The communication processing unit G4 may also add information about the RSU in which the malfunction has been detected to the header/payload of the host vehicle status message that is periodically transmitted. In other words, the communication processing unit G4 may cause the host vehicle status message to function as a malfunction detection message.

A configuration in which the diagnostic results of the forward RSU are shared via vehicle-to-vehicle communication allows the in-vehicle device 2 to respond (e.g., notify the driver) based on a notification from the preceding vehicle, taking into account the possibility that the forward RSU 1 may not be functioning properly even before the vehicle enters the communication area of the target RSU. Furthermore, a configuration in which the diagnostic results of the RSU diagnostic unit G3 are shared between in-vehicle devices 2 via vehicle-to-vehicle communication allows the RSU diagnostic unit G3 to more accurately determine whether a malfunction has occurred in the target RSU by integrating the diagnostic results from multiple in-vehicle devices 2. For example, the RSU diagnostic unit G3 may determine whether the target RSU is operating normally by majority vote. The communication processing unit G4 may transmit a data set indicating this to other devices or the management server 3, not only when it is determined that a malfunction has occurred in the target RSU, but also when it is determined that the target RSU is operating normally. The message indicating the determination result of the RSU diagnostic unit G3 may also be called a diagnostic result report.

The notification control unit G5 performs a malfunction notification process, which notifies the driver of a malfunction detected by the RSU diagnosis unit G3 in the front RSU (target RSU). Notification of a malfunction in the front RSU can be achieved using one or more of the following: displaying an image on the display 45, outputting a warning sound, turning on an indicator, applying vibrations, and applying a steering reaction force. Hereinafter, an RSU in which a malfunction has been detected will also be referred to as an error RSU.

For example, if the error RSU is an RSU1 that has been used in the past, the notification control unit G5 displays a specified malfunction notification image as a malfunction notification process. An RSU1 that has been used in the past is an RSU1 from which a support message has been received during a past trip. A trip here refers to a series of trips from when the driving power source is turned on to when it is turned off. The number of times the error RSU has been used is determined by referencing the usage history data stored in storage 113. An RSU1 that is not registered in the usage history data, in other words, an RSU1 that has been used zero times, corresponds to an RSU1 that the vehicle has never used in the past.

Furthermore, if the number of times the error RSU has been used is 0, the notification control unit G5 may not notify the driver that a malfunction has occurred in the RSU 1. Furthermore, if the error RSU is an RSU 1 that has been used a predetermined number of times or more in the past, the notification control unit G5 may notify the driver of the malfunction of the RSU 1 in a stronger manner than when the number of times it has been used is less than the predetermined number. The notification control unit G5 may change the notification manner regarding the malfunction of the RSU 1 depending on the number of times it has been used in the past. Elements that make up the manner of notification using images include the display position, display size, whether or not to blink, and color. Elements that make up the manner of notification using sound include the volume, the output interval of the warning sound, and frequency (pitch) of the sound.

When a malfunction is detected in an RSU 1 that is used frequently, the notification control unit G5 preferably notifies the driver in a more prominent (stronger) manner than when a malfunction is detected in an RSU 1 that is used infrequently. The notification control unit G5 may be configured to change the notification manner to a more prominent manner as the number of uses increases. With this configuration, if an RSU 1 along a road that the driver regularly travels is not functioning properly, the driver will be more likely to recognize this. As a result, the driver will be more likely to take action, such as driving more carefully than usual or checking the surrounding area. In other words, the risk of the driver placing excessive trust in an RSU 1 that is not functioning properly can be reduced. Paradoxically, when a malfunction is detected in an RSU 1 that is used infrequently or has no usage history, the notification control unit G5 may weaken the intensity of the notification or omit the notification altogether compared to when a malfunction is detected in an RSU 1 that is used regularly. With this configuration, the risk of the driver being annoyed can be reduced.

If the notification control unit G5 receives an RSU message and the sender of the received message is functioning normally, it displays a service-in image Im2 at a predetermined position on the display 45. The notification control unit G5 may be provided in the support processing unit G1 as one of its functions. The notification control unit G5 may also be provided as an HMI control unit that controls the HMI (Human Machine Interface) of the display 45, etc.

<Supplementary information on the operation of the notification control unit>
The notification control unit G5 may perform a notification control process based on the detection of a malfunction of the front RSU by the RSU diagnosis unit G3. In one aspect, the notification control process is a process for notifying the driver of the malfunction of the front RSU. For example, the notification control process may include steps S21 to S28 as shown in FIG. 10.

Step S21 is a step in which the RSU detection unit G31 searches for a forward RSU. For example, the RSU detection unit G31 searches for a forward RSU based on map data showing the installation location of RSU1 or usage history data. Step S61 may be a process of sending a message to RSU1 requesting that it return a response signal. The vehicle-mounted device 2/RSU diagnosis unit G3 as the RSU detection unit G31 may perform an active scan in step S61. If a forward RSU is not found, this flow ends. On the other hand, if a forward RSU is found, step S22 is executed.

Step S22 is a step in which the RSU diagnostic unit G3 determines whether or not a malfunction has occurred in the front RSU. As mentioned above, whether or not a malfunction has occurred in the front RSU can be determined in a variety of ways. In addition, a variety of information can be used as information for determining whether or not a malfunction has occurred in the front RSU. The RSU diagnostic unit G3 can determine whether or not a malfunction has occurred in the front RSU using the content of the signal received from the front RSU, the reception status of the signal from the front RSU, or data received from the management server 3 or other devices.

If no malfunction is detected in the front RSU (S22 NO), this flow ends. If no malfunction is detected in the front RSU, the assistance processing unit G1 performs appropriate driving assistance processing using the assistance message received from the front RSU. On the other hand, if it is determined that a malfunction has occurred in the front RSU (S22 YES), the vehicle-mounted unit 2 performs step S23.

Step S23 is a step in which the notification control unit G5 references the usage history data stored in storage 113 and obtains the number of times the forward RSU has been used as the error RSU. The number of times the error RSU has been used can be determined by searching the usage history data using the RSU-ID/installation location of the error RSU as a search key. Nu in the figure indicates the number of times the error RSU has been used.

Step S24 is a step for determining whether the number of times the error RSU has been used is 0. Step S24 corresponds to a step for determining whether the error RSU has been used in the past. The notification control unit G5 can determine that the number of times the error RSU has been used is 0 based on the fact that information about the error RSU is not registered in the usage history data. Furthermore, the notification control unit G5 can determine that the number of times the error RSU has been used is 1 or more based on the fact that information about the error RSU is registered in the usage history data.

If the number of times the error RSU has been used is 0 (S24 YES), the notification control unit G5 hides the service-in image (S25). In addition, the support processing unit G1 changes the operation settings so that driving support processing based on messages from the error RSU is not performed. Step S25 corresponds to control that ignores the existence of the RSU 1 in which a malfunction has been detected if the RSU 1 has not been used before.

On the other hand, if the number of uses of the error RSU is not 0 (S24 NO), the notification control unit G5 determines in step S26 whether the number of uses is less than a predetermined switching threshold (Th). The switching threshold is a threshold for switching between providing a discreet notification of a malfunction in the front RSU and providing a relatively noticeable notification. The switching threshold is set to a value that indicates, based on past usage history, that the driver is aware of the presence of the relevant RSU 1 and is expecting assistance from that RSU 1. For example, the switching threshold can be set to 5 or 10 times.

Notification in a conspicuous manner refers to notification in a manner intended to make the driver clearly aware that a malfunction has occurred in the front RSU. Notification in a conspicuous manner involves outputting a voice message/sound effect at a volume above a predetermined value, or applying vibration. A conspicuous manner corresponds to outputting a stimulus of sufficient intensity to attract the driver's attention. On the other hand, notification in a modest manner refers to notification in a manner that is relatively less stimulating than a notification in a conspicuous manner. A modest manner refers to a notification mode that aims to not bother the occupants. Notification in a modest manner refers to notification in a manner that mainly involves displaying an image, does not apply vibration to the driver, and sets the output volume below a predetermined value. Setting the output volume below a predetermined value includes not outputting any sound.

A discreet mode can also be described as an inconspicuous mode. The notification control unit G5 of this embodiment is configured to be able to control the notification mode in two stages: a noticeable mode and a discreet mode. Of course, the notification control unit G5 may be configured to be able to select from three or more notification modes, each with a different stimulus intensity, according to the type of malfunction, the driver's reliance on the support of RSU1, and the number of uses. The malfunction notification process can be divided into a discreet notification process and an emphasis notification process depending on the intensity of the notification mode (stimulus).

If the number of times the error RSU has been used is less than the switching threshold (S26 YES), the notification control unit G5 performs a discreet notification process (S27). The discreet notification process is a process for discreetly notifying that a malfunction has occurred in the front RSU. The discreet notification process includes displaying a discreet notification image Im3 at a predetermined position on the display 45. The discreet notification image Im3 is a malfunction notification image formed in a discreet manner. The malfunction notification image is an image that indicates that a malfunction has occurred in the front RSU. This configuration corresponds to a configuration for displaying a malfunction notification image in a discreet manner.

The discreet notification image Im3 can be, for example, as shown in Figure 11, an image in which a cross (x) is placed to the side of the RSU icon and text Tx3 is placed nearby to indicate that the RSU is out of service. A combined image in which a cross is placed to the side of the RSU icon is also referred to as an RSU outage icon. In one aspect, the discreet notification image Im3 shown in Figure 11 can be understood as an image in which text Tx3 is placed to the side of the RSU outage icon. The display position of the discreet notification image Im3 can be the same as that of the service in image Im2. For example, the discreet notification image Im3 can be displayed so that the RSU icon is in the same position as that of the service in image Im2.

In this disclosure, the display positions of the service-in image Im2 and the discreet notification image Im3 are referred to as the basic display positions. The basic display positions may be set to relatively inconspicuous locations, such as the top, bottom, right, or left edge of the display area of the display 45. Note that the color of the RSU icon in the service-in image Im2 may be set to white, blue, or green, while the RSU icon in the discreet notification image Im3 may be set to gray, yellow, red, or the like. The status of the RSU in front may be expressed by the different colors of the RSU icons.

In this embodiment, the notification control unit G5 performs discreet notification processing and does not output a warning sound (notification sound). In other words, if the number of uses of the error RSU is less than the switching threshold, the notification control unit G5 does not output a warning sound (notification sound). Notifications regarding malfunctions in RSU1 whose number of uses is below a predetermined value are limited to displaying an icon image, thereby reducing the risk of bothering the driver. Furthermore, because a malfunction notification image is displayed even though no sound is output, a driver who notices that assistance by RSU1 is not being provided can recognize the system's operating status by visually checking the basic display position. Alternatively, the discreet notification processing may be accompanied by the output of sound effects at a volume that is not bothersome.

Furthermore, if the number of times the error RSU has been used is equal to or greater than the switching threshold (S26 NO), the notification control unit G5 performs an emphasis notification process (S28). The emphasis notification process corresponds to a process of notifying in a conspicuous manner that a malfunction has occurred in the front RSU. The emphasis notification process includes displaying an emphasis notification image Im4, which is a malfunction notification image formed in a conspicuous manner, at a predetermined position on the display 45. The emphasis notification process also includes outputting a warning sound (notification sound) from the speaker 46 simultaneously with, prior to, or a predetermined time after the display of the emphasis notification image.

For example, as shown in FIG. 12, the notification control unit G5 displays an image containing text directly or indirectly indicating that the front RSU has failed as an emphasis notification image Im4 in the center of the display screen of the display 45. This configuration corresponds to a configuration in which a malfunction notification image is displayed in a conspicuous manner. The display position of the emphasis notification image is referred to as the temporary display position. The temporary display position may be a position that is more easily visible to a driver facing forward of the vehicle than the basic display position. The size of the emphasis notification image Im4 is larger than the modest notification image Im3. The notification control unit G5 may also display an RSU pause icon Im4a at the basic display position in parallel with the emphasis notification image Im4. Furthermore, if the in-vehicle system VS has a meter display and a HUD as the display 45, the display destination of the emphasis notification image Im4 may be set to the HUD.

<About the effects>
Drivers tend to become familiar with the support services of RSUs 1 on frequently used routes. Consequently, when passing through a service spot of a frequently used RSU 1, the driver may tend to operate the vehicle assuming that the support service from that RSU 1 is available. However, if a malfunction occurs in the RSU 1, the service may be completely stopped or the service quality (e.g., object detection accuracy) may be reduced. From the driver's perspective, whether the frequently used RSU 1 is operating normally can be important information.

On the other hand, it is highly likely that a malfunction in an RSU 1 that has never been used before will not be of importance to the driver. This is because the driver does not expect or anticipate receiving support services from an RSU 1 that they have never used before. In addition, it is difficult for the driver to even realize that an RSU 1 is installed on a road that they are traveling on for the first time. A notification of a malfunction in an RSU 1 that they have never used will be of little importance to the driver and may actually be a nuisance to them.

In other words, the importance/impact of a malfunction in the forward RSU 1 may differ depending on the number of times the driver has used that RSU 1. The present disclosure was created based on this idea, and when the vehicle-mounted device 2 detects that a malfunction has occurred in the RSU 1 located in front of the vehicle, it changes the notification mode to the driver depending on the number of times that RSU 1 has been used. Note that changing the notification mode here also includes ceasing notification.

For example, if the above-mentioned in-vehicle device 2 detects a malfunction in an RSU 1 that has never been used before, it will not notify the driver of the malfunction. This control mode can reduce the risk of causing inconvenience to the driver.

Furthermore, when the onboard device 2 recognizes that a malfunction has occurred in an RSU 1 that has been used a predetermined number of times or more, it notifies the driver that a malfunction is occurring in the forward RSU in a more noticeable manner than when it recognizes that a malfunction has occurred in an RSU 1 that has been used a predetermined number of times or more. For RSUs 1 that are used frequently, the driver is likely to rely on the support services of that RSU 1, and the impact of a malfunction occurring can be significant. With the above configuration, the driver can easily recognize in advance any malfunctions in the RSU 1 that they use on a daily basis. As a result, it is expected that the driver will perform driving operations more carefully than usual without relying on the support of the RSU 1.

Furthermore, notifications regarding malfunctions in RSU1 that have been used less than a predetermined number of times are limited to displaying an icon image. This configuration reduces the risk of causing inconvenience to the driver. Furthermore, because the malfunction notification image is displayed, a driver who notices that assistance by RSU1 is not being provided can recognize the operating status of the front RSU based on the image display.

One possible configuration is one in which, when the vehicle-mounted unit 2 is able to receive a signal from the RSU 1, a specific reception icon is displayed on the meter display. The reception icon is an icon image indicating that the RSU 1 service is available/that radio waves from the roadside unit are being received, and may correspond to the service-in image Im2. The display of the reception icon can be used as a means of determining that the roadside unit ahead is operating normally.

However, it is difficult for the driver to determine whether the RSU in front is operating normally just by whether the reception icon is displayed. Outside the distribution area of RSU1, the reception icon will be hidden even if RSU1 is operating normally. In other words, there are two cases in which the reception icon will be hidden: when outside the distribution area, or when RSU1 is malfunctioning. For this reason, it is difficult for the driver to determine the status of the RSU in front just by whether the reception icon is displayed. Furthermore, the driver may not always be paying attention to the display position of the reception icon.

To address the above issue, the in-vehicle device 2 displays a malfunction notification image, which is separate from the service-in image, upon detecting a malfunction in the forward RSU. With this configuration, if the driver is unable to receive service from RSU 1, they can distinguish whether the reason is due to their location (outside the distribution area) or a malfunction in RSU 1.

Furthermore, in the assumed configuration, even if there is a malfunction in the area monitoring sensor, the receiving icon itself may be displayed normally if the wireless equipment is functioning normally. Therefore, the driver will not notice a malfunction in the area monitoring sensor, or a deterioration in the object recognition ability of RSU1. Furthermore, even if the wireless equipment of RSU1 is normal, if there is a malfunction in the monitoring sensor, it is possible that the driver will not be notified of a moving object (for example, an oncoming vehicle or a pedestrian) that should have been notified.

To address this issue, the vehicle-mounted device 2 can also detect malfunctions in components other than the wireless unit 12. The vehicle-mounted device 2 also displays a malfunction notification image when it detects a malfunction in a component other than the wireless unit 12. Therefore, with this configuration, the driver can recognize that a malfunction has occurred in a component other than the communication function.

Unlike traffic lights and electronic bulletin boards, the operating status of the RSU 1 is often not visually recognizable. In fact, the driver may not even be aware of the location of the RSU 1. This makes it difficult for the driver to determine whether an RSU installed at an intersection or other location they are about to pass is operating normally. To address this issue, the configuration of the in-vehicle device 2 described above notifies the driver of any malfunctioning RSU 1 via image and audio. This makes it easier for the driver to determine whether an RSU installed at an intersection or other location they are about to pass is operating normally.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and the various modifications described below are also included within the technical scope of the present disclosure. Furthermore, various modifications other than those described below can be implemented without departing from the gist of the present disclosure. For example, the various supplements and modifications described below can be implemented in appropriate combinations as long as no technical contradictions arise. Note that components having the same functions as those described above will be assigned the same reference numerals, and their description may be omitted. Furthermore, when only part of the configuration is mentioned, the above description can be applied to the other parts.

<Modification (1)>
In the above embodiment, the configuration for changing the mode of the malfunction notification process (notification mode) based on the number of times the error RSU is used has been described. However, the vehicle-mounted device 2 may also change the notification mode based on the number of warnings. For example, if the number of times the warning process based on the assistance message received from the error RSU has been performed is zero, the malfunction notification process is canceled, whereas if the number of past warnings is one or more, the malfunction notification process is performed. Furthermore, similar to the aforementioned number of uses, the intensity of the warning may be changed in conjunction with the number of warnings. For example, if the number of warnings is equal to or greater than a predetermined value (e.g., three times), an emphasis notification process is performed, whereas if the number of warnings is less than the predetermined value, a more subdued notification process is performed. This configuration also achieves the same effects as the above embodiment. It is also assumed that some drivers have the RSU 1's assistance message-based warning function turned off. Drivers who routinely turn off the assistance message-based warning function are less interested in the operating status of the RSU 1 and therefore likely do not need the malfunction notification process. A configuration for determining the mode of the malfunction notification process based on the number of warnings can reduce the risk of causing inconvenience to drivers who routinely turn off the assistance message-based warning function.

As another example, the vehicle-mounted device 2 may change the notification mode using both the number of uses and the number of warnings. For example, the notification control process may be configured as shown in Figure 13. The notification control process shown in Figure 13 includes steps S33 to S39. Steps S31 to S35 are the same as steps S21 to S25.

Step S36 is a step for determining whether the number of uses is less than a predetermined first switching threshold (Th1). The first switching threshold can be set to 5, 10, 15, etc. Step S37 is a step for determining whether the number of warnings is less than a predetermined second switching threshold (Th2). The second switching threshold can be set to 1, 3, 5, etc. The second switching threshold is set to a value smaller than the first switching threshold. Steps S38 to S39 are similar to steps S27 to S28. Each step can be executed in the order indicated by the arrows in Figure 13.

According to the flow shown in Figure 13, the vehicle-mounted device 2 performs emphasis notification processing if the number of warnings is equal to or greater than the second switching threshold, even if the number of uses is less than the first switching threshold. For locations where warning processing has been performed, the driver is likely aware that an RSU 1 is installed and that assistance services are available. There is also a high likelihood that the driver expects to be able to receive similar assistance services again. In this way, if a malfunction occurs in an RSU 1 that has performed warning processing, even if the number of uses is low, safety can be improved by performing emphasis notification processing rather than discreet notification processing.

In addition, the notification control unit G5 may change the notification mode based on the number of interventions. For example, if the number of interventions based on the support message received from the error RSU is zero, the malfunction notification process is canceled, while if the number of past interventions is one or more, the malfunction notification process is performed. Furthermore, as with the number of uses described above, the intensity may be changed in conjunction with the number of interventions, such as by performing an emphasis notification process if the number of interventions is a predetermined value (e.g., two) or more, or by performing a more subdued notification process if the number of warnings is less than the predetermined value. The vehicle-mounted unit 2 may be configured to perform an emphasis notification process if the number of interventions is one or more, even if the number of uses/warnings is below the predetermined value. The vehicle-mounted unit 2 may change the notification mode regarding a malfunction of the RSU 1 by appropriately combining the number of uses, warnings, and interventions of the RSU 1 in which a malfunction has been detected.

<Modification (2)>
The vehicle-mounted device 2 may notify the location/cause of the malfunction. For example, if an abnormality is detected in the camera 15, the vehicle-mounted device 2 may display a malfunction notification image including text/icon indicating that the camera 15 of the RSU 1 is malfunctioning. The vehicle-mounted device 2 may also determine whether the malfunction type of the RSU 1 will result in a service outage. The malfunction type may be classified into a service outage type and a quality (reliability) degradation type. The service outage type includes malfunctions in all or a predetermined number or more of the area monitoring sensors, a failure of the radio unit 12, a failure of the RSU control unit 11, etc. A malfunction that corresponds to a quality degradation type includes a failure of some of the area monitoring sensors, a failure of the GNSS receiver 13, etc.

If the malfunction occurring in the front RSU corresponds to a service outage type, the vehicle-mounted unit 2 may display an outage image, which is a malfunction notification image indicating that service is out of service. Furthermore, if the malfunction occurring in the front RSU corresponds to a quality degradation type, the vehicle-mounted unit 2 may display a quality degradation image. The quality degradation image is a malfunction degradation image indicating that service quality is degraded (function is degraded).

The vehicle-mounted device 2 may also change the image displayed depending on whether the RSU 1 in which the malfunction has occurred has stopped or is continuing to distribute assistance messages. If the RSU 1 in which the malfunction has been detected is continuing to distribute assistance messages, a degraded quality image is displayed. On the other hand, if the RSU 1 in which the malfunction has been detected has stopped distributing assistance messages, an inactive image is displayed. Whether or not assistance message distribution is continuing can be determined based on the reception status of assistance messages from the RSU 1 in question and notifications from the RSU 1, management server 3, or other vehicle-mounted devices 2.

<Modification (3)>
Although the above description has been given of an embodiment in which both the RSU 1 and the onboard device 2 each have a function for diagnosing the RSU 1, this is not limiting. The onboard device 2 does not have to have the RSU diagnosis unit G3. The RSU 1 does not have to have the self-diagnosis unit F2. It is sufficient that any of the RSU 1, the onboard device 2, or the management server 3 has a function for diagnosing the RSU 1.

<Modification (4)>
The on-board device 2 may display a bad environment icon when a forward camera or the like detects the presence of a large vehicle within a predetermined distance ahead of the vehicle. The bad environment icon is an icon image indicating that the environment is bad for road-to-vehicle communication, and in reality, that there is a risk that road-to-vehicle communication will fail/that assistance via road-to-vehicle communication may not be available. This configuration is expected to have the effect of encouraging the driver to perform more careful driving operations.

<Modification (5)>
The content of the assistance data/the services of the RSU1 can be changed as appropriate. The assistance data may be traffic light-related data indicating the lighting status of a traffic light. The traffic light-related data may include lighting cycle information such as the remaining time for which the current lighting status will be maintained and the next lighting status in addition to the current lighting status. The message/communication packet/communication frame indicating the assistance data may correspond to an SPaT (Signal Phase and Timing) message. The RSU1 may be provided integrally with the traffic light.

The assistance data may also be control data for assisting the vehicle in autonomous driving within an intersection. The assistance services provided by RSU1 may be used to implement/continue autonomous driving. For example, the assistance data transmitted by RSU1 may be data related to driving control, such as stopping/starting/target speed/steering angle of the autonomous vehicle. The assistance data may also be camera image data or map data showing the shape of the intersection, etc.

While the operation of each component of the RSU 1 was described assuming that it was installed at an intersection in the above embodiment, the RSU 1 may also be installed at locations other than intersections. The RSU 1 may be located at a junction or branching point on a highway. The RSU 1 may distribute assistance data such as a data set indicating traffic conditions near the junction or branching point, such as the location and speed of vehicles within the monitoring area. The RSU 1 may also be located near the exit of a tunnel. In this case, the RSU 1 may distribute assistance data such as a data set indicating wind speed, rainfall, road surface conditions, and the presence or absence of traffic congestion near the tunnel exit. An RSU 1 installed in a road section with poor visibility may distribute a data set notifying of moving objects and road shape within the monitoring area. The content of the assistance data may differ for each RSU 1. Road sections with poor visibility include intersections with fences, trees, or buildings at the corners, gradient changes from an uphill to a downhill slope, and sharp curves with a curvature greater than a predetermined value. The monitoring area can be set to cover areas that are likely to be blind spots for the vehicle driver/camera.

<Modification (7)>
As shown in Fig. 14, the in-vehicle system VS may include an automatic driving ECU 48. The in-vehicle device 2 may be configured to be able to communicate with the automatic driving ECU 48 via the in-vehicle network VN or directly via a dedicated cable. The automatic driving ECU 48 is an ECU that controls the drive system 47 based on the detection results of the perimeter monitoring sensor 42 and map data, thereby causing the vehicle to automatically drive. The automatic driving ECU 48 is also called an automatic driving device.

In a configuration in which the in-vehicle device 2 is connected to the autonomous driving ECU 48, an error signal may be sent to the autonomous driving ECU 48 based on the detection of a malfunction in the front RSU. The error signal indicates that a malfunction has occurred in the front RSU. ErrSg in Figure 14 represents an error signal.

With this configuration, the autonomous driving ECU 48 can implement emergency control such as reducing speed, making a handover request, changing route, or initiating a Minimal Risk Maneuver (MRM) based on receiving an error signal. In other words, the autonomous driving ECU 48 can plan and implement a response based on the operating status of the forward RSU with ample time to spare. This configuration makes it possible to improve the safety of the autonomous driving system. Note that a handover request is a process that requests the driver to take over driving operations, and may also be referred to as a driving change request/handover request.

<Modification (8)>
The management server 3 may determine that a malfunction has occurred in one RSU 1 based on the receipt of malfunction detection reports from multiple onboard devices 2 within a certain period of time for that RSU 1. A configuration in which the status of the RSU 1 is determined based on reports from multiple onboard devices 2 can reduce the risk of erroneously determining the status of the RSU 1.

In addition, information about the RSU 1 in which a malfunction is detected may be delivered in advance from the management server 3 to the in-vehicle device 2. This configuration makes it possible to perform malfunction notification processing early, and to perform processing such as proposing/selecting a driving route that avoids the RSU 1 in which the malfunction has occurred. In particular, if the RSU 1 in which the malfunction has occurred is an RSU 1 that provides information essential for implementing/continuing autonomous driving, the autonomous driving ECU 48 may be able to select an alternative route or make a handover request early based on the notification from the management server 3.

<Modification (9)>
The RSU 1 does not need to be equipped with an area monitoring sensor such as a camera 15. The RSU 1 for distributing traffic light-related data only needs to be connected to a lighting control unit that controls the lighting state of the traffic light, and the area monitoring sensor can be an optional element. The hardware/functions equipped in the RSU 1 can be changed as appropriate depending on the service of the RSU 1.

<Modification (10)>
Road-to-vehicle communication may be implemented using, for example, Bluetooth (registered trademark), Wi-Fi (registered trademark), ZigBee (registered trademark), UWB-IR (Ultra Wide Band - Impulse Radio), EnOcean (registered trademark), Wi-SUN (registered trademark), etc. Bluetooth standards include BLE (Bluetooth Low Energy) and Bluetooth Classic. Various Wi-Fi standards can also be adopted, such as IEEE802.11n, IEEE802.11ac, and IEEE802.11ax (so-called Wi-Fi 6).

<Additional remarks (1)>
The above-described vehicle-mounted device 2 can be used in various vehicles traveling on roads. The vehicle-mounted device 2 of the present disclosure can be mounted on various vehicles that can travel on roads, such as four-wheeled vehicles, two-wheeled vehicles, three-wheeled vehicles, etc. A motorized bicycle can also be included in the category of two-wheeled vehicles. The vehicle-mounted device 2 may be used in a robot taxi, an unmanned bus, a vehicle serving as an unmanned delivery robot, or a patrol car that automatically travels a predetermined route for road facility inspection/crime prevention. The vehicle-mounted device 2 may be configured to be detachable by the user. The vehicle-mounted device 2 may be a smartphone, tablet, laptop, or the like equipped with the above-described short-range communication function that is brought into the vehicle by the user.

<Additional remarks (2)>
The present disclosure also includes the following technical ideas: The following technical ideas are also applicable to a communication control method.

[Technical thought 1]
An in-vehicle device configured to be able to receive assistance data, which is data for assisting a vehicle in traveling, distributed from each of a plurality of roadside devices installed along a road,
a roadside device detection unit (G31) that detects a roadside device in front of the vehicle, the roadside device being the roadside device;
a roadside device diagnosis unit (G3) that determines whether or not a malfunction has occurred in the forward roadside device based on the content of a signal received from the forward roadside device, a reception status of the signal from the forward roadside device, or data received from an external device other than the forward roadside device;
a record processing unit (G2) for storing usage history data, which is data about the roadside device that has been used, in a history storage unit (M1);
a notification control unit (G5) that controls a notification to a driver regarding a malfunction of the forward roadside device,
The notification control unit
The vehicle-mounted device changes a mode of notifying the driver about the malfunction of the forward roadside device depending on whether the driver has used the forward roadside device in the past in which the malfunction has occurred.

[Technical philosophy 2]
The vehicle-mounted device according to Technical Idea 1,
the recording processing unit records the number of times of use for each roadside device,
The notification control unit is an on-board device that changes the notification mode depending on the number of times the forward roadside device in which a malfunction has occurred is used.

[Technical philosophy 3]
The vehicle-mounted device according to Technical Idea 1 or 2,
The notification control unit is an in-vehicle device that makes the notification more noticeable as the number of times the road side ahead where a problem occurs increases.

[Technical thought 4]
The vehicle-mounted device according to any one of technical concepts 1 to 3,
The recording processing unit is an in-vehicle device that stores data of the roadside device as the source of the received assistance data as the usage history data.

[Technical philosophy 5]
The vehicle-mounted device according to any one of technical concepts 1 to 4,
the recording processing unit stores, as the usage history data for each roadside device, information indicating whether or not a warning process has been performed based on the assistance data received from the roadside device;
The notification control unit is an on-board device that changes the notification mode depending on whether or not the warning process has been performed using the assistance data from the forward roadside device in which a malfunction has occurred.

[Technical philosophy 6]
The vehicle-mounted device according to Technical Idea 5,
The notification control unit is an on-board device that, if the warning process has been performed using the assistance data from the forward roadside device in which a malfunction has occurred, makes the notification manner more noticeable than if the warning process has not been performed.

[Technical Thought 7]
The vehicle-mounted device according to Technical Idea 5,
the recording processing unit records the number of warnings, which is the number of times the warning process has been performed;
The notification control unit is an in-vehicle device that makes the notification more noticeable as the number of times the warning using the assistance data from the forward roadside device in which a malfunction occurs increases.

[Technical Thought 8]
The vehicle-mounted device according to any one of technical concepts 1 to 7,
the recording processing unit stores, as the usage history data for each roadside device, information on whether or not an operation intervention process based on the assistance data received from the roadside device has been performed;
The notification control unit is an on-board device that changes the notification mode depending on whether or not the operation intervention process has been performed using the assistance data from the forward roadside device in which a malfunction has occurred.

[Technical Thought 9]
The vehicle-mounted device according to Technical Concept 8,
The notification control unit is an on-board device that, if the operation intervention process has been performed using the assistance data from the forward roadside device in which a malfunction has occurred, makes the notification mode more noticeable than if the operation intervention process has not been performed.

[Technical Thought 10]
The vehicle-mounted device according to any one of technical concepts 1 to 9 is used in connection with an automatic driving device,
The notification control unit is an on-board device configured to, when it determines that a malfunction has occurred in the forward roadside device, transmit an error signal to the automatic operation device indicating that a malfunction has occurred in the forward roadside device.

<Additional remarks (3)>
The various flowcharts shown in this disclosure are merely examples, and the number of steps constituting the flowcharts and the execution order of the processes can be changed as appropriate. Furthermore, the devices, systems, and methods described in this disclosure may be implemented by a special-purpose computer comprising a processor programmed to execute one or more functions embodied in a computer program. The devices and methods described in this disclosure may be implemented using dedicated hardware logic circuits. The devices and methods described in this disclosure may be implemented by one or more special-purpose computers configured by combining a processor that executes a computer program with one or more hardware logic circuits. Examples of processors (computation cores) that can be used include a CPU, MPU, GPU, and DFP (Data Flow Processor). Some or all of the functions of this disclosure may be implemented using a system-on-chip (SoC), an integrated circuit (IC), or an FPGA (Field-Programmable Gate Array). The concept of IC also includes an application-specific integrated circuit (ASIC). The computer program may be stored as instructions executed by a computer on a computer-readable, non-transient tangible storage medium. Examples of storage media for the program include hard disk drives (HDDs), solid state drives (SSDs), and flash memory. The scope of the present disclosure also includes programs for causing a computer to function as the RSU control unit 11, control module 22, and management server 3, as well as non-transient tangible storage media such as semiconductor memory on which the programs are stored.

1 RSU (roadside unit), 2 In-vehicle unit, 3 Management server (external device), 11 RSU control unit, F1 Support information distribution unit, F2 Self-diagnosis unit, F3 Status notification unit, 22 Control module, 223 Storage, M1 History memory unit, G1 Support processing unit, G2 Recording processing unit, G3 RSU diagnosis unit (roadside unit diagnosis unit), G31 RSU detection unit (roadside unit detection unit), G4 Communication processing unit, G5 Notification control unit

Claims (11)

An in-vehicle device configured to be able to receive assistance data, which is data for assisting a vehicle in traveling, distributed from each of a plurality of roadside devices installed along a road,
a roadside device detection unit (G31) that detects a roadside device in front of the vehicle, the roadside device being the roadside device;
a roadside device diagnosis unit (G3) that determines whether or not a malfunction has occurred in the forward roadside device based on the content of a signal received from the forward roadside device, a reception status of the signal from the forward roadside device, or data received from an external device other than the forward roadside device;
a record processing unit (G2) for storing usage history data, which is data about the roadside device that has been used, in a history storage unit (M1);
a notification control unit (G5) that controls a notification to a driver regarding a malfunction of the forward roadside device,
The notification control unit
The vehicle-mounted device changes a mode of notifying the driver about the malfunction of the forward roadside device depending on whether the driver has used the forward roadside device in the past in which the malfunction has occurred. 2. The vehicle-mounted device according to claim 1,
the recording processing unit records the number of times of use for each roadside device,
The notification control unit is an on-board device that changes the notification mode depending on the number of times the forward roadside device in which a malfunction has occurred is used. 3. The vehicle-mounted device according to claim 2,
The notification control unit is an in-vehicle device that makes the notification more noticeable as the number of times the forward roadside device in which a malfunction occurs increases. 3. The vehicle-mounted device according to claim 1,
The recording processing unit is an in-vehicle device that stores data of the roadside device as the source of the received assistance data as the usage history data. 3. The vehicle-mounted device according to claim 1,
the recording processing unit stores, as the usage history data for each roadside device, information indicating whether or not a warning process has been performed based on the assistance data received from the roadside device;
The notification control unit is an on-board device that changes the notification mode depending on whether or not the warning process has been performed using the assistance data from the forward roadside device in which a malfunction has occurred. 6. The vehicle-mounted device according to claim 5,
The notification control unit is an on-board device that, if the warning process has been performed using the assistance data from the forward roadside device in which a malfunction has occurred, makes the notification manner more noticeable than if the warning process has not been performed. 6. The vehicle-mounted device according to claim 5,
the recording processing unit records the number of warnings, which is the number of times the warning process has been performed;
The notification control unit is an in-vehicle device that makes the notification more noticeable as the number of times the warning using the assistance data from the forward roadside device in which a malfunction occurs increases. 3. The vehicle-mounted device according to claim 1,
the recording processing unit stores, as the usage history data for each roadside device, information on whether or not an operation intervention process, such as automatic braking or steering, based on the assistance data received from the roadside device has been performed;
The notification control unit is an on-board device that changes the notification mode depending on whether or not the operation intervention process has been performed using the assistance data from the forward roadside device in which a malfunction has occurred. 9. The vehicle-mounted device according to claim 8,
The notification control unit is an on-board device that, if the operation intervention process has been performed using the assistance data from the forward roadside device in which a malfunction has occurred, makes the notification mode more noticeable than if the operation intervention process has not been performed. 3. The vehicle-mounted device according to claim 1 or 2, which is used in connection with an automatic driving device,
The notification control unit is an on-board device configured to transmit an error signal indicating that a malfunction has occurred in the forward roadside unit to the automatic operation device based on the roadside unit diagnosis unit determining that a malfunction has occurred in the forward roadside unit. 1. A notification control method implemented by at least one processor for notifying a driver of an operation state of a roadside device that distributes assistance data, which is data for assisting vehicle driving, comprising:
Detecting a forward roadside device that is the roadside device located in front of a vehicle that is a vehicle in which the processor is used (S21);
Executing a process of storing usage history data, which is data about the roadside device that has been used, in a history storage unit (M1) (S12);
determining whether or not a malfunction has occurred in the roadside device ahead based on the content of a signal received from the roadside device ahead, a reception status of the signal from the roadside device ahead, or data received from an external device other than the roadside device ahead (S22);
and changing a notification mode to the driver regarding the malfunction of the forward roadside unit depending on whether or not the driver has used the forward roadside unit in the past in which the malfunction has occurred (S24 to S28, S34 to S39).