FR3112443A1 - Vehicle communication method and device - Google Patents

Abstract

A vehicle communication method and device are provided. To this end, a first collective perception message, called the first CPM message, is transmitted by a second vehicle (12) to a first vehicle (11). The first CPM message comprises first information representative of the detection of an event by the second vehicle (12). The first vehicle (11) verifies the event detected by the second vehicle (12) using one or more on-board systems and/or sensors. A second level of quality to be associated with the detection of the event is determined from the first level of quality received and the result of the verification. A second CPM message is finally transmitted with the second associated quality level, the second CPM message comprising second information representing detection of the event. Figure for abstract: Figure 1

Description

Vehicle communication method and device

The invention relates to a communication method and device for a vehicle, in particular an automobile. The invention relates in particular to the communication of messages between vehicles to signal a particular event, for example a potential danger.

Technology background

With the development of connected vehicles capable of driving in an autonomous or semi-autonomous mode, that is to say without driver assistance for at least some traffic situations, knowledge of its environment by a vehicle is paramount.

Thus, new communication technologies are emerging that allow the exchange of information between vehicles and/or between vehicles and the infrastructure that surrounds them. New information and communication technologies applied to the field of transport have appeared, such as the ITS G5 (from the English "Intelligent Transportation System G5" or in French "Système de transport intelligent G5") in Europe or DSRC (Dedicated Short Range Communications) in the United States of America, both of which are based on the IEEE 802.11p standard or technology based on cellular networks named C-V2X (from English “Cellular - Vehicle to Everything” or in French “Cellulaire – Vehicule vers tout”) which is based on 4G based on LTE (from English “Long Term Evolution” or in French “Long-term evolution”) and soon 5G.

New standards or communication standards are also emerging to structure and standardize the exchange of data between vehicles. For example, the ETSI (from the English "European Telecommunication Standards Institute" or in French "Institut européen des norms de telecommunication") defines formats for collective perception messages, known as CPM messages (from the English "Collective Perception System "), which make it possible to transport data relating to the perception that a vehicle has of its environment, that is to say that such a message makes it possible to transport data relating to the detection of the environment by one or multiple vehicle sensors or systems that generate such a message. The format and the data transported by a CPM message are for example described in document ETSI TR 103 562 v2.1.1 published in December 2019 or in document ETSI TS 103 324.

One of the problems associated with the use of these collective perception data by the vehicle(s) using them concerns the trust that can be placed in such data, trust being linked to the quality of the data.

An object of the present invention is to be able to evaluate the confidence that it is possible to have in perceptual collaboration data emitted by a vehicle.

Another object of the present invention is to improve knowledge of its environment for a vehicle traveling in a road environment.

According to a first aspect, the invention relates to a communication method for a vehicle, the method being implemented by a first vehicle, the method comprising the following steps:

- reception of a first collective perception message, called first CPM message, the first CPM message being transmitted by a second vehicle according to a vehicle-to-everything type communication mode, called V2X, the first CPM message comprising first information representative of detection of an event by the second vehicle, a first detection quality level being associated with the first CPM message;

- verification of the event from at least one on-board system in the first vehicle;

- determination of a second level of quality to be associated with the detection of the event from the first level of quality and a result of the verification;

- transmission of a second CPM message comprising second information representing detection of the event, the second quality level being associated with the second CPM message.

According to a variant, the second quality level is higher than the first quality level when the verification confirms detection of the event by the at least one on-board system of the first vehicle; and the second quality level is lower than the first quality level when the verification does not confirm the detection of the event by the at least one on-board system of the first vehicle.

According to another variant, the first level of quality is determined from a set of criteria specific to the event, the event belonging to a set of events comprising:

- high-risk meteorological event;

- triggering of a security system;

- detection of a specific vehicle;

- traffic event.

According to an additional variant, the determination of the second quality level comprises the following steps:

- detection of the event from at least one on-board system in the first vehicle;

- determination of a third level of quality associated with the detection from the set of criteria specific to the event;

- determining the second quality level from the first quality level and the third quality level.

According to yet another variant, the first quality level is included in the first CPM message and the second quality level is included in the second CPM message.

According to an additional variant, the second CPM message corresponds to the first CPM message, the second information representative of detection of the event corresponding to the first information representative of detection of the event.

According to another variant, the at least one embedded system belongs to a set of systems comprising:

- an object detection system comprising at least one sensor, the at least one sensor belonging to a set of sensors comprising a camera, a radar and a LIDAR;

- a driving assistance system, known as the ADAS system;

- a control system for at least one member of the first vehicle;

- an environmental data measurement system.

According to a second aspect, the invention relates to a device comprising a memory associated with a processor configured for the implementation of the steps of the method as described above according to the first aspect of the invention.

According to a third aspect, the invention relates to a vehicle, for example of the automotive type, comprising a device as described above according to the second aspect of the invention.

According to a fourth aspect, the invention relates to a computer program which comprises instructions adapted for the execution of the steps of the method according to the first aspect of the invention, this in particular when the computer program is executed by at least one processor.

Such a computer program can use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other desirable form.

According to a fifth aspect, the invention relates to a computer-readable recording medium on which is recorded a computer program comprising instructions for the execution of the steps of the method according to the first aspect of the invention.

On the one hand, the recording medium can be any entity or device capable of storing the program. For example, the medium may comprise a storage means, such as a ROM memory, a CD-ROM or a ROM memory of the microelectronic circuit type, or even a magnetic recording means or a hard disk.

On the other hand, this recording medium can also be a transmissible medium such as an electrical or optical signal, such a signal being able to be conveyed via an electrical or optical cable, by conventional or hertzian radio or by self-directed laser beam or by other ways. The computer program according to the invention can in particular be downloaded from an Internet-type network.

Alternatively, the recording medium may be an integrated circuit in which the computer program is incorporated, the integrated circuit being adapted to execute or to be used in the execution of the method in question.

Brief description of figures

Other characteristics and advantages of the invention will emerge from the description of the non-limiting embodiments of the invention below, with reference to the appended figures 1 to 3, in which:

schematically illustrates a road environment in which a first vehicle travels, according to a first particular embodiment of the present invention;

schematically illustrates a device on board the first vehicle of FIG. 1, according to a particular embodiment of the present invention;

illustrates a flowchart of the different steps of a communication method implemented by the first vehicle of FIG. 1, according to a particular embodiment of the present invention.

A method and a communication device for a vehicle will now be described in what will follow with reference to FIGS. 1 to 3. The same elements are identified with the same reference signs throughout the description which will follow.

According to a particular and non-limiting embodiment of the invention, a communication method implemented by a first vehicle comprises the reception of a first collective perception message, called the first CPM message. This first CPM message is advantageously transmitted by a second vehicle according to a mode of communication of the vehicle-to-everything type, called V2X (from the English “Vehicle-to-Everything”). Such a first CPM message advantageously comprising first information representative of the detection of an event by the second vehicle, that is to say by a set of sensors of the second vehicle, a first level of detection quality being associated with the first CPM message. The first vehicle having received the first CPM message then verifies the event detected by the second vehicle using one or more systems on board the first vehicle, a set of sensors being associated with this or these on-board systems. A second level of quality to be associated with the detection of the event is determined from the first level of quality received and the result of the verification. This second level of quality takes for example a higher value than that of the first level of quality when the verification of the event makes it possible to observe that the event detected by the second vehicle is indeed observed by the first vehicle. A second CPM message is finally transmitted with the second associated quality level, the second CPM message comprising second information representing detection of the event.

The association of a quality level with each CPM message and the verification, by a first vehicle, of the event detected by a second vehicle to adjust the quality level associated with the detection of the event allows each vehicle receiving a CPM message to determine the level of confidence it may have in this received CPM message. This also allows any vehicle to improve knowledge or perception of its environment, using or not the information received in a CPM message depending on the associated quality level.

schematically illustrates a road environment 1 associated with a V2X (Vehicle-to-everything) type communication network, according to a particular and non-limiting embodiment of the present invention .

FIG. 1 illustrates a first vehicle 11 traveling in a road environment 1 comprising, for example, a first traffic lane 1001 and a second traffic lane 1002 in the opposite direction to that of the first traffic lane 1001. A second vehicle 12 also travels in the road environment 1, for example in front of the first vehicle 11 on the traffic lane 1001.

A third vehicle 13 also moves in the road environment 1, for example on the second traffic lane 1002.

The first vehicle 11 and the second vehicle 12 are advantageously each equipped with a communication device for transmitting and receiving data intended for another vehicle and/or a server of a network infrastructure. Each communication device can be likened to a node of a network, for example an ad hoc wireless network.

The vehicles 11 and 12 advantageously communicate using a communication system called V2X, short and/or long range, for example based on the 3GPP LTE-V or IEEE 802.11p standards of ITS G5 and/or C-V2X. In such a V2X communication system, each vehicle embeds a node to allow communication from vehicle to vehicle V2V (from the English “vehicle-to-vehicle”), from vehicle to infrastructure V2I (from the English “vehicle-to- -infrastructure”) and/or vehicle-to-pedestrian V2P, the pedestrians being equipped with mobile devices (for example a smart phone (“Smartphone”)) configured to communicate with vehicles.

The infrastructure of the network comprises for example communication devices 101, 102, each device 101, 102 corresponding for example to an antenna of a cellular network of the 4G or 5G LTE type or to a UBR ("Roadside Unit") , each corresponding to a network node, in addition to the nodes equipping vehicles or pedestrians.

According to a particular exemplary embodiment, all the nodes (that is to say the communications devices associated with the vehicles 10 to 15 and the antennas or UBRs 101, 102) of the network form, for example, an ad hoc wireless network (also called WANET (from the English “Wireless Ad Hoc Network”) or MANET (from the English “Mobile Ad Hoc Network”)), corresponding to a decentralized wireless network. The ad hoc wireless network advantageously corresponds to a vehicular ad hoc network (or VANET, standing for “Vehicular Ad hoc NETwork”) or to an intelligent vehicular ad hoc network (or InVANET, standing for “Intelligent Vehicular Ad hoc NETwork”), also known as the “GeoNetworking” network. In such a network, 2 or more vehicles each carrying a node can communicate with each other in the context of V2V vehicle-to-vehicle communication; each vehicle can communicate with the infrastructure set up as part of a V2I vehicle-to-infrastructure communication; each vehicle can communicate with one or more pedestrians equipped with mobile devices (for example a smart phone (“Smartphone”)) as part of a V2P vehicle-to-pedestrian communication (“vehicle-to- walker”).

The nodes corresponding to the antennas (or UBR) 101 and 102 are advantageously connected to one or more remote servers or to the “cloud” 100 (or in French “cloud”) via a wired and/or wireless connection. The antennas or UBR 101 and 102 can thus act as a relay between the “cloud” 100 and each vehicle 11 to 13.

Vehicles 11 to 13 correspond for example to so-called autonomous vehicles, that is to say vehicles whose driving is, at least in part, managed by one or more automatic systems. The level of autonomy of vehicles 11 to 13 is for example between 0 and 5 (0 for a vehicle having no autonomy and whose driving is under the full supervision of the driver and 5 for a completely autonomous vehicle).

The 5 levels of autonomy of the classification of the federal agency in charge of road safety are:

- level 0: no automation, the driver of the vehicle fully controls the main functions of the vehicle (engine, accelerator, steering, brakes);

- level 1: driver assistance, automation is active for certain vehicle functions, the driver retaining overall control over the driving of the vehicle; cruise control is part of this level, like other aids such as ABS (anti-lock braking system) or ESP (programmed electro-stabilizer);

- level 2: automation of combined functions, the control of at least two main functions is combined in the automation to replace the driver in certain situations; for example, adaptive cruise control combined with lane centering allows a vehicle to be classified as level 2, as does automatic parking assistance;

- level 3: limited autonomous driving, the driver can hand over complete control of the vehicle to the automated system which will then be in charge of critical safety functions; however, autonomous driving can only take place under certain determined environmental and traffic conditions (only on the motorway, for example);

- level 4: complete autonomous driving under conditions, the vehicle is designed to carry out all the critical safety functions on its own over a complete journey; the driver provides a destination or navigation instructions but is not required to make himself available to regain control of the vehicle;

- level 5: completely autonomous driving without driver assistance in all circumstances.

The classification of the International Organization of Motor Vehicle Manufacturers is similar to that listed above, with the difference that it has 6 levels, level 3 of the American classification being divided into 2 levels in that of the International Organization of Car manufacturers.

The first vehicle 11 and the second vehicle 12 are each equipped with one or more on-board systems, each associated with one or more sensors configured to detect particular objects or events, to measure physical quantities.

The system(s) on board the first vehicle 11 and/or the second vehicle 12 correspond, for example, to one or more of the following systems:

- an object detection system comprising one or more sensors such as for example one or more cameras, one or more millimeter wave radars and/or one or more LIDAR (from the English "Light Detection And Ranging" or "Laser Detection And Ranging”);

- a driving assistance system, known as the ADAS system, for example:

● an electronic stability control system fitted to the vehicle, known by the acronyms ESC (from the English “Electronic Stability Control” or in French “Contrôle Electronique de la Stabilité”), DSC (from the English “Dynamic Stability Control” or in French "Dynamic Stability Control") or even ESP (from English "Electronic Stability Program" or in French "Electronic Stability Program"),

● a lane keeping assistance system, known as the LKA (Lane Keep Assist) system,

● a system that detects grip conditions, known as the DST system (from the English “Dynamic Steering Torque” or in French “Dynamic Steering Couple”),

● an electronic anti-skid system, known as the ASR system (from the English "Anti-Slip Regulation" or in French "Anti-skid Control"), such an ASR system regulating acceleration to limit the loss of grip of the drive wheels,

● an emergency braking assistance system configured to detect emergency braking and amplify the braking force exerted by the driver, such a system being for example coupled to an automatic hazard warning lights system,

● a system called ABS (from the German "Antiblockiersystem" or in French "system anti-locking wheels"),

● an automatic emergency braking system, known as the AEB (Advanced Emergency Braking) system,

● a speed limiter system,

● a cruise control system,

● an adaptive cruise control system, known as the ACC (Adaptive Cruise Control) system;

- a system for controlling at least one component of the first vehicle, for example for controlling any component such as the engine of the vehicle, the wheels, the indicators, the windscreen wipers, the lighting system (dipped beam , position lights, fog lights, etc.);

- an environmental data measurement system, for example using sensors to measure temperature, pressure, humidity, visibility.

Based on the data received from one or more sensors of one or more of the systems listed above, the first vehicle 11 and/or the second vehicle 12 is able to detect the presence of event(s) such as For example :

- high-risk meteorological event, for example an area of fog, an area of freezing fog, an area of precipitation (rain, snow), an area with ice, etc. ;

- triggering of a safety system, for example one or more of the ESC, ABS, DST, AEB systems;

- detection of a specific vehicle, for example an emergency vehicle (for example an ambulance, fire brigade, police);

- detection of a pedestrian or an object on the traffic lane;

- traffic event, for example an accident, a traffic jam, an area with high traffic density.

The presence or detection of one or more events is advantageously signaled from one vehicle to another by exchanging one or more so-called CPM messages, such a CPM message being for example described in document ETSI TR 103 562 v2.1.1 published in December 2019.

A CPM message includes a PDU (Protocol Data Unit) header or in French “Protocol Data Unit” compliant with the ITS (English "Intelligent Transport Systems" or in French "Intelligent Transport Systems"), and 4 containers (from the English "container"), namely: a management container (from the English "Management Container"), a data container station (from the English "Station Data Container"), a sensor information container, called SICs (from the English "Sensor Information Containers") and a container of perceived objects, called POCs (from the English “Perceived Object Containers”).

The header includes data elements such as the protocol version, the message identifier and the identifier of the transmitting station (for example the first vehicle 11 or the second vehicle 12).

The management container is essential and provides basic information about the transmitting vehicle, for example its position. Position information is used as a reference for objects detected by the transmitting vehicle.

The station data container is optional and includes additional information about the transmitting vehicle, for example its speed, direction or acceleration.

A SIC container includes data describing the capabilities of the sensors on board the transmitting vehicle. A CPM message can include up to 10 SICs.

A POC container includes information on an object detected by the sensors on board the vehicle sending the CPM message, for example the distance between the detected object and the sending vehicle, the speed and dimensions of the detected object, and the time at which the measurements were taken. A CPM message can include up to 255 POCs.

A detected object corresponds for example to a particular event, for example the detection of an object in the road environment 1 (vehicle, obstacle, pedestrian), the detection of the triggering of a security system of the transmitting vehicle, the detection of an event or a climatic zone at risk, the detection of a traffic event (accident, works, traffic jam).

The exchange of one or more CPM messages between vehicles thus allows the vehicles concerned to have a better knowledge of their environment.

The process described below and relating to the communication of CPM messages between vehicles is advantageously implemented by the first vehicle 11, for example by one or more computers of the on-board system of the first vehicle 11.

In a first operation, the first vehicle 11, for example a computer of the on-board system of the first vehicle 11, receives from the second vehicle 12 a first CPM message via a wireless link according to a V2X communication mode.

The first CPM message is for example received from the network infrastructure, for example from the element 101, the second vehicle 12 having transmitted this first CPM message to the network infrastructure which then retransmits it to the first vehicle 11.

According to another exemplary embodiment, the first vehicle 11 communicates with the second vehicle according to a V2V type direct communication mode and the first CPM message is received directly from the second vehicle 12. A direct communication mode is for example in accordance with:

- ITS G5 in Europe or DSRC (Dedicated Short Range Communications) in the United States of America, both of which are based on the IEEE 802.11p standard; Or

- LTE-V Mode 4 (from English “Long-Term Evolution – Vehicle Mode 4” or in French “Evolution à long terme –véhicle Mode 4”) which allows V2V communications, also called “sidelink” communications (or in French "side link")) based on a direct communication interface of LTE called PC5; such technology is described for example in the article entitled "Analytical Models of the Performance of C-V2X Mode 4 Vehicular Communications", written by Manuel Gonzalez-Martin, Miguel Sepulcre, Rafael Molina-Masegosa and Javier Gozalvez, and published in 2018 .

The first message comprises a set of first information relating to the detection of one or more events by the second vehicle 12, that is to say by one or more on-board systems (and the sensors associated with this or these systems) in the vehicle 12. The event corresponds for example to the detection of a high-risk weather zone 110 and/or to the detection of an emergency vehicle 13.

Concerning the meteorological zone at risk 110, the first data associated with its detection are for example obtained by the activation of one or more organs or components (lighting lights, fog lights, windscreen wipers, front de-icing system or rear) of the second vehicle 12, either automatically or manually by the driver of the second vehicle 12.

For example, the first information corresponds to data obtained following the activation of the fog lights of the second vehicle 12. The activation of the fog lights thus makes it possible to characterize the zone 110 as being a zone of fog. The first data resulting from the activation of the fog lights are thus representative of the detection of a meteorological zone at risk 110 corresponding to a zone of fog.

According to another example, the first information corresponds to data obtained following the activation of the windscreen wipers of the second vehicle 12. The activation of the windscreen wipers thus makes it possible to characterize the zone 110 as being a zone of precipitation. The first data resulting from the activation of the windshield wipers are thus representative of the detection of a meteorological risk zone 110 corresponding to a precipitation zone, for example a rain zone.

A first quality level representative of the quality of the detection of the event or events signaled in the first CPM message is associated with the first CPM message. The first quality level is transmitted by the second vehicle 12 to the first vehicle 11 with the first CPM message. According to a particular example of implementation, the first quality level is included in the first CPM message, for example integrated in the header or in a container, for example in the SIC or POC container.

The first quality level is for example determined by the second vehicle 12 from a set of criteria or rules specific to the detected event. All of the criteria, rules, evaluation conditions and index tables necessary for determining the first level of quality are stored in the memory of the computer of the second vehicle 12 implemented for the evaluation of the third level of quality.

As examples, a set of events is provided below with for each event the possible quality levels and the associated rules to determine the quality level.

Example 1: fog

Table 1 below lists all the quality levels that can be associated with a fog detection type event and the conditions to be met to validate each quality level of the set.

Event detection Quality Score value No compatible implementation 0 Condition a) is met 1 Condition b) is met 2 Condition c) is met 3 Condition d) is met 4

Driver reaction and lighting status:

a) the driver triggers the switching on of the front and rear foglamps, the switching on being maintained for a duration greater than a threshold, for example 20 seconds;

b) the driver switches on the front and rear foglamps and the speed of the vehicle is below a threshold, for example below 20 km/h, these criteria being fulfilled for a duration above a threshold, for example 20 seconds ;

Visibility distance measuring device:

c) the visibility due to fog is below a threshold, for example below 80 meters with a tolerance of plus or minus 40 meters for a duration above a threshold, for example above 5 seconds;

d) the visibility due to fog is below a threshold, for example below 80 meters with a tolerance of plus or minus 40 meters and the speed of the vehicle is below a threshold, for example below 60 km/h, for a duration greater than a threshold, for example greater than 5 seconds.

Example 2: precipitation

Table 2 below lists all the quality levels that can be associated with a precipitation detection type event and the conditions to be met to validate each quality level of the set.

Event detection Quality Score value No compatible implementation 0 Condition a) is met 1 Condition b) is met 2 Condition c) is met 3 Condition d) is met 4

Wiper intensity and light status:

a) the intensity of the windscreen wipers is at the highest level, the front fog lamps are on, all for a duration greater than a threshold, for example 20 seconds;

b) the intensity of the windshield wipers is at the highest level, the front fog lamps are on and the speed of the vehicle is below a threshold, for example below 60 km/h, all for a period greater than one threshold, for example 20 seconds;

Device for detecting rain, wiper intensity level and lighting status:

c) the amount of precipitation is at a minimum at, for example, 90% of the maximum precipitation detection capacity and the intensity level of the windscreen wipers is at the highest level, all for a duration greater than a threshold, by example longer than 20 seconds;

d) the amount of precipitation is at a minimum at, for example, 90% of the maximum precipitation detection capacity, the intensity level of the windscreen wipers is at the highest level, the front fog lamps are on and the vehicle speed is less than a threshold, for example less than 60 km/h, all for a duration greater than a threshold, for example 20 seconds.

Example 3: loss of traction

Table 3 below lists all the quality levels that can be associated with an event of the detection type of a loss of traction or grip and the conditions to be met to validate each quality level of all.

Event detection Quality Score value No compatible implementation 0 Condition a) or e) is met 1 Condition b) is met 2 Condition c) or f) is met 3 Condition g) is met 4 Condition d) or h) is met 5 Condition i) is met 6 Condition j) is met 7

=> Positive acceleration:

a) ASR system, accelerator pedal, vehicle acceleration and vehicle speed:

the ASR system must be active for at least 200 ms for example; the accelerator pedal is depressed on average for more than 30% of its travel while the ASR regulation is in progress; the acceleration of the vehicle is less than 40% of the acceleration of the vehicle on a surface with a high grip index (hard asphalt: 0.85 for example).

b) ASR system, accelerator pedal, vehicle acceleration and vehicle speed:

the ASR system must be active for at least 200 ms for example; the accelerator pedal is depressed on average for more than 30% of its travel while the ASR regulation is in progress; the acceleration of the vehicle is less than 20% of the acceleration of the vehicle on a surface with a high grip index (hard asphalt: 0.85 for example).

c) ASR system, accelerator pedal, vehicle acceleration and vehicle speed:

the ASR system must be active for at least 200 ms for example; the accelerator pedal is depressed on average for more than 30% of its travel while the ASR regulation is in progress; the acceleration of the vehicle is less than 10% of the acceleration of the vehicle on a surface with a high grip index (hard asphalt: 0.85 for example).

d) ASR system and accelerator pedal:

the ASR system must be active for at least 200 ms for example; the accelerator pedal is depressed on average more than 30% of its stroke while the ASR regulation is in progress.

=> Negative acceleration:

e) ABR system, brake pressure and vehicle deceleration:

the ABS system must be active for at least 200 ms for example; the brake pressure is 20% higher than the maximum permissible brake pressure; the deceleration of the vehicle is less than 50% of the deceleration of the vehicle on a surface with a high grip index (hard asphalt: 0.85 for example).

f) ABR system, brake pressure and vehicle deceleration:

the ABS system must be active for at least 200 ms for example; the brake pressure is 20% higher than the maximum permissible brake pressure; the deceleration of the vehicle is less than 25% of the deceleration of the vehicle on a surface with a high grip index (hard asphalt: 0.85 for example).

g) ABR system, brake pressure and vehicle deceleration:

the ABS system must be active for at least 200 ms for example; the brake pressure is 20% higher than the maximum permissible brake pressure; the deceleration of the vehicle is less than 10% of the deceleration of the vehicle on a surface with a high grip index (hard asphalt: 0.85 for example).

h) ABS system and brake pressure:

the ABS system must be active for at least 200 ms for example; the brake pressure is 20% higher than the maximum permissible brake pressure.

=> Estimation of the coefficient of friction:

i) the coefficient of friction is less than 0.3 for at least 5 seconds.

j) the coefficient of friction is less than 0.2 for at least 5 seconds.

Example 4: automatic triggering of hazard warning lights

Table 4 below lists all the quality levels that can be associated with an event such as automatic triggering of the hazard warning lights in the event of emergency braking and the conditions to be met to validate each level of overall quality.

Event detection Quality Score value No compatible implementation 0 Condition a) is met 1 Condition a) is met and the current longitudinal acceleration of the vehicle is less than – 4m/s² 2 Condition b) is met 3

a) detection of a signal triggering the automatic activation of the hazard warning lights in the event of emergency braking, as defined in the European standard "ECE regulations No. 48, No. 13 and 13H" published on 18 January 2013;

b) the current speed of the vehicle is greater than a threshold, for example greater than 20 km/h and the current acceleration is less than a threshold, for example less than -7 m/s² for a minimum duration of 500 ms for example .

Example 5: triggering emergency braking

Table 5 below lists all the quality levels that can be associated with an event of the emergency braking trigger type and the conditions to be met to validate each quality level of the set.

Event detection Quality Score value No compatible implementation 0 Condition a) is met 1 Condition a) is met and the current longitudinal acceleration of the vehicle is less than – 4m/s² 2

a) detection of a signal requiring the automatic activation of the emergency braking system.

Example 6: detection of an emergency vehicle in intervention

Table 6 below lists all the quality levels that can be associated with an event of the detection type of an emergency vehicle in intervention and the conditions to be met to validate each level of quality of the 'together.

Event detection Quality Score value No compatible implementation 0 Condition a) is met 1 Conditions a) and b) are met 2 Conditions a) and c) are met 3 Conditions a), b) and c) are met 4

(a) the emergency vehicle's flashing light is on;

b) the emergency vehicle siren is on;

(c) the emergency vehicle is not stopped.

Of course, the examples listed above are provided for purely illustrative purposes and are not limiting. Furthermore, the invention relates to the detection of any event relating to any particular situation encountered in a road environment, for example:

- detection of a stationary intervention vehicle;

- detection of a stationary intervention vehicle with the driver of the vehicle outside the vehicle (detected for example from a camera on board the vehicle or a sensor in the driver's seat);

- detection of a stationary vehicle on the roadway or the edge of the roadway;

- detection of a broken down or damaged vehicle;

- detection of a line of stationary vehicles, for example the end of the line;

- the detection of a pedestrian on the roadway or on the edge of the roadway;

- the detection of an object on the road or on the edge of the road.

In a second operation, the first vehicle 11 decodes the first information received in the first CPM message. The first vehicle 11 then triggers the verification of the event(s) signaled by the second vehicle 12 in the first CPM message using one or more on-board systems and/or on-board sensors (for example radar, LIDAR, camera), depending on the type of reported event.

In a third operation, the first vehicle 11 determines a second quality level to be associated with the detection of the event or events signaled by the second vehicle 12 in the first CPM message from the result of the verification of the second operation and the first level of quality received and associated with the first CPM message.

For example, if the verification result confirms the detection of the event by the first vehicle 11 in addition to the detection by the second vehicle signaled in the first CPM message, then the second quality level takes a higher value than that of the first level. A higher value of the quality level indicates that the confidence in the first information representative of the detection of the event by the second vehicle 12 is high since the detection of the event is confirmed by the first vehicle 11.

Conversely, if the result of the verification invalidates, or at least does not confirm, the detection of the event by the first vehicle 11, then the second level of quality takes on a lower value than that of the first level.

According to a variant embodiment, the determination of the second quality level is a function of a third quality level associated with the detection of the event signaled in the first CPM message by the first vehicle 11, that is to say by one or more systems on board the first vehicle 11 and/or one or more sensors on board the first vehicle 11. The determination of the third level of quality is advantageously obtained by using the criteria specific to the event which were also used for the determination of the first quality level by the second vehicle 12, examples of such criteria or conditions being provided in examples 1 to 6 above. According to this variant, the second quality level is obtained as a combination of the first quality level and the third quality level. For example, the second level of quality corresponds to the average of the first and second level of quality, rounded up to the upper integer for example. According to another example, if the value of the third quality level is greater than the value of the first quality level, then the second quality level takes the value of the third quality level. According to this variant, all the criteria, rules and conditions for evaluating the level of quality are stored in the memory of the computer of the first vehicle 11 implemented for the evaluation of the third level of quality.

In a fourth operation, the first vehicle 11 transmits a second CPM message comprising a set of second information representative of the detection of the event. The first vehicle 11 also transmits the second quality level associated with this second CPM message, the second quality level being for example included in the second CPM message.

The second CPM message is transmitted via a wireless link according to the V2X communication mode, either via the network infrastructure in V2I mode or in direct V2V communication mode. The second CPM message is for example transmitted to all the vehicles present in the coverage area of the antenna 101 and/or of the antenna 102 or to all the vehicles present in the transmission area covered by the first vehicle 11 when the transmission takes place in direct V2V communication mode.

According to a particular embodiment, the second CPM message corresponds to the first CPM message, that is to say that the first vehicle 11 retransmits the first CPM message received, the second information corresponding to the first information.

According to another exemplary embodiment, the second information included in the second CPM message is different from the first information and corresponds to the data received from the system(s) and/or sensors on board the first vehicle 11 implemented for the detection of the event by the first vehicle 11.

The transmission of a second CPM message or the retransmission of the first CPM message by the first vehicle makes it possible to confirm the detection of the event carried out initially by the second vehicle 12, which allows other vehicles receiving this second message to enrich their knowledge of the environment with an adjusted level of confidence via the reception of the second level of quality associated with the detection of the event.

schematically illustrates a communication device 2 for a vehicle, according to a particular and non-limiting embodiment of the present invention. The device 2 corresponds for example to a device on board the first vehicle 11 and the second vehicle 12, for example a computer. The device 2 is for example configured to determine a level of quality to be associated with data or information representative of one or more events detected by sensors on board the vehicle and to transmit and/or receive data according to a V2X type link. .

The device 2 is for example configured for the implementation of the operations described with regard to FIG. 1 and/or the steps of the method described with regard to FIG. 3. Examples of such a device 2 comprise, without being limited thereto , a server, a computer, a computing device, on-board electronic equipment such as a vehicle on-board computer, an electronic calculator such as an ECU, a telematics control unit TCU (from the English "Telematic Control Unit”), a smart phone (“smartphone”), a tablet, a laptop or a combination of several of the items listed above. The elements of device 2, individually or in combination, can be integrated in a single integrated circuit, in several integrated circuits, and/or in discrete components. The device 2 can be made in the form of electronic circuits or software (or computer) modules or else a combination of electronic circuits and software modules. According to different particular embodiments, the device 2 is coupled in communication with other similar devices or systems, for example via a communication bus or through dedicated input/output ports.

The device 2 comprises one (or more) processor(s) 20 configured to execute instructions for carrying out the steps of the method and/or for executing the instructions of the software or software embedded in the device 2. The processor 20 can include integrated memory, an input/output interface, and various circuits known to those skilled in the art. The device 2 further comprises at least one memory 21 corresponding for example to a volatile and/or non-volatile memory and/or comprises a memory storage device which can comprise volatile and/or non-volatile memory, such as EEPROM, ROM, PROM, RAM, DRAM, SRAM, flash, magnetic or optical disk.

The computer code of the on-board software or software comprising the instructions to be loaded and executed by the processor is for example stored on the memory 21. The tables of indexes and criteria or rules for evaluating the level of quality are for example also stored on the memory 21.

According to a particular and non-limiting embodiment, the device 2 comprises a block 22 of interface elements for communicating with external devices, for example a remote server or the "cloud", a vehicle communication system, a computer, a TCU. Block 22 interface elements include one or more of the following interfaces:

- RF radio frequency interface, for example of the Bluetooth® or Wi-Fi® type, LTE (from English "Long-Term Evolution" or in French "Evolution à long terme"), LTE-Advanced (or in French LTE-advanced ), 3GPP 5G;

- USB interface (from the English "Universal Serial Bus" or "Universal Serial Bus" in French);

- HDMI interface (from the English “High Definition Multimedia Interface”, or “Interface Multimedia Haute Definition” in French).

Data are for example loaded to the device 2 via the block 22 interface using a 4G (or LTE Advanced according to 3GPP release 10 – version 10) or 5G network.

According to another particular embodiment, the device 2 comprises a communication interface 23 which makes it possible to establish communication with other devices, such as for example the GPS-type location system, the mobile communication system (GSM, GPRS, Wi-Fi, Bluetooth, LTE, LTE-V, ITS G5)) or the radars of the radar system via a communication channel 230. The communication interface 23 corresponds for example to a transmitter configured to transmit and receive information and/or data via the communication channel 230. The communication interface 23 corresponds for example to a wired network of the CAN type (from the English “Controller Area Network” or in French “Network of controllers”), CAN FD (from the English "Controller Area Network Flexible Data-Rate" or in French "Réseau de Contrôleurs à Flow de Data Flexible"), Ethernet Automotive (or in French "Ethernet automobile"), FlexRay (according to the ISO 17458 standard) or Ethernet (depending on a standard ISO/IEC 802.3).

According to an additional particular embodiment, the device 2 can supply output signals to one or more external devices, such as a display screen, one or more loudspeakers and/or other peripherals respectively via interfaces output not shown.

illustrates a flowchart of the different steps of a communication method for a vehicle, according to a particular and non-limiting embodiment of the present invention. The method is for example implemented by a device on board the first vehicle 11 or by the device 2 of FIG. 2.

In a first step 31, a first collective perception message, called the first CPM message, is received. This first CPM message is for example transmitted by a second vehicle according to a communication mode of the vehicle-to-everything type, called V2X. The first CPM message advantageously comprises first information representing detection of an event by the second vehicle, a first level of detection quality being associated with the first CPM message.

In a second step 32, the event signaled in the first CPM message is verified by the first vehicle from at least one system and/or sensor on board the first vehicle.

In a third step 33, a second level of quality to be associated with the detection of the event is determined from the first level of quality and a result of the verification.

In a fourth step 34, a second CPM message comprising second information representing detection of the event is transmitted, the second quality level being associated with the second CPM message.

Of course, the invention is not limited to the embodiments described above but extends to a method for detecting an event or an object by a vehicle and to the device configured for the implementation of the method. . The invention also relates to a method for determining a level of quality or a level of confidence to be associated with the detection of an event by a vehicle, and to the device configured for the implementation of the method.

The invention also relates to a vehicle, for example an automobile or more generally a land motor vehicle, comprising the device 2 of FIG. 2.

Claims (10)

A vehicle communication method, said method being implemented by a first vehicle (11), said method comprising the following steps:
- reception (31) of a first collective perception message, said first CPM message, said first CPM message being transmitted by a second vehicle (12) according to a vehicle-to-everything type communication mode, said V2X, said first CPM message comprising first information representative of detection of an event by said second vehicle (12), a first quality level of said detection being associated with said first CPM message;
- verification (32) of said event from at least one on-board system in said first vehicle (11);
- determination (33) of a second quality level to be associated with said detection of said event from said first quality level and a result of said verification;
- transmission (34) of a second CPM message comprising second information representative of detection of said event, said second quality level being associated with said second CPM message. Process according to Claim 1, in which:
- said second quality level is higher than said first quality level when said verification confirms detection of said event by said at least one on-board system of the first vehicle (11);
- said second quality level is lower than said first quality level when said verification does not confirm the detection of said event by said at least one embedded system of the first vehicle (11). Method according to claim 1 or 2, for which said first level of quality is determined from a set of criteria specific to said event, said event belonging to a set of events comprising:
- high-risk meteorological event;
- triggering of a security system;
- detection of a specific vehicle;
- traffic event. Method according to claim 3, wherein said determination of the second quality level comprises the following steps:
- detection of said event from said at least one on-board system in said first vehicle (11);
- determination of a third level of quality associated with said detection from said set of criteria specific to said event;
- determining said second quality level from said first quality level and said third quality level. Method according to one of Claims 1 to 4, for which the said first quality level is included in the said first CPM message and the said second quality level is included in the said second CPM message. Method according to one of Claims 1 to 5, for which said second CPM message corresponds to said first CPM message, said second information representative of detection of said event corresponding to said first information representative of detection of said event. Method according to one of Claims 1 to 6, for which the said at least one embedded system belongs to a set of systems comprising:
- Object detection system comprising at least one sensor, said at least one sensor belonging to a set of sensors comprising a camera, a radar and a LIDAR;
- driving assistance system, known as the ADAS system;
- control system of at least one member of said first vehicle;
- environmental data measurement system. Device (2) comprising a memory (21) associated with at least one processor (20) configured for implementing the steps of the method according to any one of Claims 1 to 7. Vehicle (11) comprising the device (2) according to claim 8. Computer program product comprising instructions adapted for the execution of the steps of the method according to one of Claims 1 to 7, when the computer program is executed by at least one processor.