WO2019201845A1

WO2019201845A1 - Device for synchronizing a primary position of a mobile object with a secondary position

Info

Publication number: WO2019201845A1
Application number: PCT/EP2019/059645
Authority: WO
Inventors: Richard Denis
Original assignee: Valeo Comfort And Driving Assistance
Priority date: 2018-04-16
Filing date: 2019-04-15
Publication date: 2019-10-24
Also published as: FR3080176B1; FR3080176A1

Abstract

The invention relates to a synchronization device (DISP) for synchronizing a primary position (POS1) of a mobile object (V1), at least one primary parameter (IP1) being associated with said primary position (POS1), according to which said synchronization device (DISP) is configured to: - receive cooperative perception messages (CPM) broadcast by at least one emitter (DIFF); - on the basis of at least part of said cooperative perception messages (CPM) received, determine a secondary position (POS2) of said mobile object (V1) and at least one associated secondary parameter (IP2); - synchronize said primary position (POS1) with said secondary position (POS2) as a function of a comparison of said at least one secondary parameter (IP2) with at least one threshold (TH).

Description

DEVICE FOR SYNCHRONIZING A PRIMARY POSITION OF A MOBILE OBJECT WITH A SECONDARY POSITION

DOMAI N E TECH N I QU E OF THE INVENTION

The present invention relates to a device for synchronizing a primary position of a moving object and an associated synchronization method.

It finds a particular but non-limiting application in the field of motor vehicles.

BACKGROUND TECH NOLOGY OF THE I NVENTION

In the field of motor vehicles, a device for calculating a primary position of a moving object such as a motor vehicle, known to those skilled in the art, is based on satellite signals and comprises a positioning system by satellite which makes it possible to obtain a geo-localized position. Such a position calculating device is used in motor vehicles to know the precise position of the motor vehicle. The geo-localized position of the motor vehicle is a parameter for various driving assistance or navigation functions.

A disadvantage of this state of the art is that in the case where the satellite signals are lost, the driving assistance or navigation functions are unusable.

In the case where the satellite signals are lost, the computing device further comprises, in a manner known to those skilled in the art, an inertial navigation device comprising one or more sensors which makes it possible to extrapolate the position of the motor vehicle .

A disadvantage of this state of the prior art is that the extrapolation is a function of the sensors present in the motor vehicle and may result in a significant error drift on the extrapolation of the position of the vehicle. motor vehicle, which renders the driving assistance or navigation functions equally unusable or which degrades the performance of the driving assistance or navigation functions.

In this context, the present invention aims to solve the aforementioned drawbacks.

D ESC RI PTION G EN E R A T E N G IN G IN I NVENTION

To this end, the invention proposes a device for synchronizing a primary position of a moving object, at least one primary parameter being associated with said primary position, according to which said synchronization device is configured to:

- receive cooperative perception messages broadcast by at least one transmitter;

from at least part of said received cooperative perception messages, determining a secondary position of said mobile object and at least one associated secondary parameter;

synchronizing said primary position with said secondary position as a function of a comparison of said at least one secondary parameter with at least one threshold.

Thus, as will be seen in detail later, the fact of using cooperative perception messages allows to know at any time a secondary position very close to the actual position of the mobile object or equal to it and of synchronizing its primary position with said secondary position so as to reduce location errors when the satellite signals are lost.

In addition, when the positioning calculation device also relies on an inertial navigation device, this also makes it possible to avoid having to correct the error drift in the extrapolation performed by the inertial navigation device. Thus, the driving assistance or navigation functions are maintained at a sufficient level of performance.

According to non-limiting embodiments, the synchronization device may further comprise one or more additional characteristics from the following.

According to a non-limiting embodiment, said primary position is a geo-localized position.

According to a non-limiting embodiment, said primary position is determined from an extrapolation of a geo-localized position.

According to a non-limiting embodiment, said at least one threshold is said minus one primary parameter.

According to a non-limiting embodiment:

said at least one primary parameter is a primary confidence level or a primary precision level; and

said at least one secondary parameter is a secondary confidence level or a secondary precision level.

According to a non-limiting embodiment, said synchronization device comprises:

a transmission unit configured to receive said cooperative perception messages;

an electronic control unit configured to determine said secondary position and said at least one associated secondary parameter;

a location unit configured to synchronize said primary position.

According to a non-limiting embodiment, said location unit is further configured to determine said primary position of said mobile object and at least one associated primary parameter.

According to a nonlimiting embodiment, said transmitter is part of another mobile object or another stationary object.

According to a non-limiting embodiment, said other mobile object is a vehicle or a mobile phone.

According to a non-limiting embodiment, said other stationary object is a fixed infrastructure.

According to a nonlimiting embodiment, said synchronization device is further configured to identify the cooperative perception messages that correspond to said mobile object.

According to a non-limiting embodiment, said locating unit comprises a satellite navigation system.

According to a non-limiting embodiment, said locating unit further comprises an inertial navigation device.

According to a nonlimiting embodiment, said synchronization device is configured to receive cooperative perception messages broadcast by a plurality of transmitters.

According to a non-limiting embodiment, said synchronization device is part of said mobile object.

There is also provided a method for synchronizing a primary position of a moving object, at least one primary parameter being associated with said primary position, comprising:

the reception of cooperative perception messages broadcast by at least one transmitter;

from at least part of said cooperative perception messages, determining a secondary position of said mobile object and at least one associated secondary parameter;

the synchronization of said primary position with said secondary position as a function of a comparison of said at least one secondary parameter with at least one threshold.

B REVE D ESC RI PTION OF FI G URS

The invention and its various applications will be better understood by reading the following description and examining the figures that accompany it. - Figure 1 shows a state of the art in which an extrapolation of a calculated primary position of a motor vehicle on a road has an error drift with respect to the actual position of said motor vehicle;

FIG. 2 represents a device for synchronizing a primary position of a motor vehicle, according to one nonlimiting embodiment of the invention;

FIG. 3a shows a diagram of a motor vehicle on a road comprising the synchronization device of FIG. 2, illustrating said motor vehicle which receives cooperative perception messages broadcast by a transmitter that is part of a mobile object, said mobile object being another motor vehicle, according to a first non-limiting embodiment;

FIG. 3b represents a diagram of a motor vehicle on a road comprising the synchronization device of FIG. 2, illustrating said motor vehicle which receives cooperative perception messages broadcast by a transmitter which is part of a stationary object, said stationary object being a fixed infrastructure, according to a second non-limiting embodiment;

FIG. 4 represents a diagram of a motor vehicle on a road comprising the synchronization device of FIG. 2, illustrating said motor vehicle which filters the cooperative perception messages received by said transmitter of FIGS. 3a or 3b which correspond to it, according to a non-limiting embodiment;

FIG. 5 represents a diagram of a motor vehicle on a road comprising the synchronization device of FIG. 2, illustrating said motor vehicle which synchronizes its primary position with a secondary position derived from the cooperative perception messages received from said transmitter of FIGS. or 3b, according to a non-limiting embodiment;

- Figure 6 shows a diagram of a motor vehicle on a road comprising the synchronization device of FIG. 2, illustrating said motor vehicle with a synchronized primary position, according to a non-limiting embodiment;

FIG. 7 illustrates a first timing diagram of a synchronization method implemented by the synchronization device of FIG. 2, according to a nonlimiting embodiment.

D ESC RI PTION D E MODES D E REALIZA TION

THE I NVENTION

Identical elements, structure or function, appearing in different figures retain, unless otherwise specified, the same references.

The invention relates to a synchronization device DISP of a primary position POS1 of a mobile object V1, at least one primary parameter IP1 being associated with said primary position POS1.

In non-limiting embodiments, the mobile object V1 is a vehicle or a mobile phone.

In a non-limiting embodiment variant, the vehicle is a motor vehicle or a vehicle without engine (sail, solar cells, etc.). In a non-limiting example, the motor vehicle is a motor vehicle.

In a non-limiting embodiment variant, the mobile phone is a so-called smart smartphone mobile phone. The mobile phone can be worn by a user of a motor vehicle, a bicycle or by a user who is a pedestrian.

In the following description, the motor vehicle is taken as a non-limiting example for the mobile object V1. This motor vehicle V1 is also called in the following description of the primary vehicle V1.

Said synchronization device DISP is described with reference to FIGS. 2 to 6.

In a non-limiting embodiment, said synchronization device DISP is part of said mobile object V1. As illustrated in FIGS. 2 to 6, the synchronization device DISP is configured to:

receive cooperative CPM perception messages broadcast by at least one DIFF transmitter (function illustrated in FIG. 2 RX (DISP, DIFF, CPM));

from at least part of said cooperative perception messages CPM, determining a secondary position POS2 of said mobile object V1 and at least one associated secondary parameter IP2 (function illustrated in FIG. 2 DET (DISP, POS2, IP2));

synchronizing said primary position POS1 with said secondary position POS2 as a function of a comparison between said at least one primary parameter IP1 and at least one threshold TH (function illustrated in FIG. 2 SYNCH (DISP, POS1, POS2, IP2, TH) ).

In a non-limiting embodiment, said synchronization device DISP is configured to determine said secondary position POS2 from all the cooperative perception messages CPM. This is the case when for example only the mobile object V1 is in the environment perceived by the transmitter DIFF.

In a non-limiting embodiment, said synchronization device DISP is further configured to compare said at least one secondary parameter IP2 with said threshold TH (function illustrated in FIG. 2 COMP (DISP, IP2, TH)).

In a non-limiting embodiment, said synchronization device DISP is further configured to identify the cooperative perception messages CPM which correspond to said mobile object V1 (function illustrated in FIG. 2 IDT (DISP, CPM (V1))).

In the rest of the description, CPM cooperative cooperation messages are also referred to as CPM messages.

In order to perform the functions described above, as illustrated in FIG. 2, in a non-limiting embodiment, the synchronization device DISP comprises: - a COMU transmission unit;

- an ECU electronic control unit;

- a LOCU localization unit.

The COMU transmission unit is a transceiver.

In non-limiting embodiment:

said at least one primary parameter IP1 is a primary confidence level IC1 or a primary precision level PR1; and

said at least one secondary parameter IP2 is a secondary confidence level IC2 or a secondary precision level PR2.

In a nonlimiting embodiment, the primary position V1 is used for driving assistance or navigation functions such as a collision avoidance function, or a lane change function, or driving functions. automated etc. As described in detail in the remainder of the description, the synchronization device DISP will synchronize the primary position POS1 determined at a time t by the primary vehicle V1 with the secondary position POS2, namely it will correct at a time t + 1 a primary position V1 with said secondary position POS2 which will have been determined at a time t.

• Determination of Ja _. posj _. tion _. primary _. POS1 _.

In a nonlimiting embodiment, said locating unit LOCU is configured to determine the primary position POS1 and at least one associated primary parameter IP1 (function illustrated in FIG. 2 DET (DISP, POS1, IP1)).

^■ First non-limiting embodiment

In a first non-limiting embodiment, said primary position POS1 is a geo-localized position. For this purpose, the location unit LOCU comprises:

- A GNSS satellite navigation system called in English "Global Navigation Satellite System", as in non-limiting examples GPSTM, GLONASSTM, GALILEOTM, BEIDOUTM etc., configured to receive satellite signals. The satellite signals make it possible to determine the primary POS1 position of the primary vehicle V1 to within a few centimeters of the actual position of said primary vehicle V1, as well as at least one associated primary parameter IP1. The determination of a geo-localized position and at least one primary parameter IP1, from satellite signals being known to those skilled in the art, it is not described here.

In a non-limiting example, when the primary parameter IP1 is a primary confidence level IC1, it can be associated with a risk of internal failure or cyber-attack determined by the location unit LOCU.

In a non-limiting example, when the primary parameter IP1 is a primary precision level PR1, it may be a 2D confidence ellipse around the primary position POS1.

As will be seen later, the synchronization device DISP is used when the satellite signals are lost or when the latter are not reliable (in case of error from the satellites or cyber attack).

^■ Second non-limiting embodiment

In a second nonlimiting embodiment, said primary position POS1 is determined from an extrapolation of a geolocated position POS1 '.

For this purpose, the location unit LOCU comprises:

- a GNSS satellite navigation system; and

an inertial navigation device INS called "Inertial Navigation System" which comprises at least one sensor.

In non-limiting examples, the inertial navigation device INS comprises at least one motion sensor (accelerometer) and / or at least one rotation sensor (gyroscope) and / or at least one magnetic sensor (magnetometer).

Said inertial navigation device INS is configured to calculate the orientation and the velocity (direction and speed) of said primary vehicle V1, this which makes it possible to have an estimated position called "dead reckoning" in English which coupled to the GNSS satellite navigation system is configured to extrapolate the geo-localized position POS1 'of said motor vehicle V1 when:

- the satellite signals are lost;

the satellite signals comprise a bad signal-to-noise ratio;

- When the satellite signals are reflected on surfaces, which degrades their accuracy.

The satellite signals are lost when the primary vehicle V1 is in a tunnel, under a bridge or in an underground car park in non-limiting examples.

Satellite signals include poor signal-to-noise ratio in urban environments with tall buildings or tall trees, in a non-limiting example.

The satellite signals are reflected when the primary vehicle V1 is in a narrow street, for example. They are reflected on the walls of the buildings of the street for example.

Figure 1 illustrates:

a geo-localized position POS1 ';

a position POS1 (t-N) at time t-N (with N an integer) to which the primary vehicle V1 comes under a tunnel for example;

POS1 (t-N) extrapolation positions up to POS1 (t);

the actual position POSr of the primary vehicle V1 in the tunnel.

As illustrated in FIG. 1, the extrapolation can rapidly diverge as time passes relative to the actual position POSr of the primary vehicle V1 because of the lack of performance of the sensors and / or the algorithm of extrapolation used. An error drift on the extrapolation can thus quickly appear. As can be seen, over time, the extrapolated position POS (t-N) drifts to the position POS1 (t) extrapolated which is very far from the actual position POSr of the primary vehicle V1.

As described later, synchronization removes this error drift.

This makes it possible to no longer have errors in driving assistance or navigation functions for example.

Thus, in non-limiting embodiments, the synchronization device DISP is configured to perform the functions described in detail hereinafter when:

- the satellite signals are lost;

the satellite signals comprise a bad signal-to-noise ratio;

Thus, the synchronization device DISP is used when the locating unit LOCU comprises a GNSS satellite navigation system and an INS inertial navigation device notably during the extrapolation, but also when the locating unit LOCU only comprises that the GNSS satellite navigation system.

In a non-limiting embodiment, the synchronization device DISP is activated at the start of the primary vehicle V1.

The various functions performed by the synchronization device DISP are described in detail below.

• Fon _.Q tipn _. of jéceptipn des _. messages _. CPM

In a non-limiting embodiment, said COMU transmission unit is configured to receive said CPM messages (function illustrated in FIG. 1 RX (DISP, DIFF, CPM) of said at least one DIFF transmitter.

The mobile object V1, here the primary vehicle V1 in the nonlimiting example taken, is configured to perform a communication, via its COMU transmission unit, with at least one DIFF transmitter.

As illustrated in FIGS. 3a and 3b, in a non-limiting embodiment, the transmitter DIFF is part of another mobile object V2 or a stationary object BS.

In a variant of non-limiting embodiment illustrated in FIG. other mobile object V2 is another motor vehicle V2. The other motor vehicle V2 is also called secondary vehicle V2 in the following description. In another variant of non-limiting embodiment not illustrated, said other mobile object V2 is a mobile phone.

In a non-limiting embodiment variant illustrated in FIG. 3b, said stationary object BS is a fixed infrastructure. In a non-limiting exemplary embodiment, the fixed infrastructure BS is a basic transmission station. Thus, the COMU transmission unit is configured to perform a communication:

with at least one secondary vehicle V2, the communication is then a so-called V2V communication. The secondary vehicle V2 is a motor vehicle with capacities more efficient than the primary vehicle V1; and or

with at least one fixed infrastructure BS, here the base transmission station, the communication is then a V2I communication.

In a manner known to the person skilled in the art, a CPM message describes the perception of a communicating entity, here the transmitter DIFF, of its environment and therefore of the objects which surround it, such as in non-limiting examples of cars, pedestrians, signs, etc. Said communicating entity shares its perception of its environment with other surrounding entities X including the primary vehicle V1. Thus, the DIFF transmitter is configured to perform a V2X communication when it is a secondary vehicle V2 or I2X when it is a fixed infrastructure. The DIFF transmitter is configured to broadcast the CPM messages (function illustrated in Figure 1 TX (DIFF, DISP, CPM)).

In a non-limiting embodiment, the COMU transmission unit is configured to receive CPM messages from a plurality of DIFF transmitters. Thus, in a nonlimiting example, the primary vehicle V1 can receive CPM messages from a plurality of secondary vehicles V2, or from a plurality of secondary vehicles V2 and / or from at least one fixed infrastructure BS, or from a plurality of secondary vehicles V2 and a plurality of fixed infrastructures BS etc.

Thus, in a non-limiting embodiment, a CPM message notably comprises INF information on the objects surrounding the DIFF transmitter, such as:

a / INFa primary information:

an identifier of an object. Said identifier is in a non-limiting example the license plate;

- the type of an object (truck, bicycle, light vehicle etc.);

- the speed of an object;

- the acceleration of an object;

- the heading of an object;

- the dimensions of an object.

This primary information INFa will identify the primary vehicle V1 among other objects surrounding the transmitter DIFF.

b / secondary information INFb:

an absolute position of the transmitter DIFF in a geocentric repository for example and a relative position of the detected objects in a repository centered on the transmitter DIFF making it possible to deduce an absolute position POS2 'of the detected objects. In a nonlimiting example, the relative position is given by measurements of angles and distances relative to the transmitter DIFF; or

an absolute position POS2 ', in a common repository of the objects detected by the transmitter DIFF.

c / tertiary information INFc on the detection capacity of the transmitter DIFF. In non-limiting examples, this tertiary INFc information is:

- the field of view of a sensor;

- the type of sensors used;

the quality level of a sensor, for example an error rate.

Note that in order to determine a relative position of an object, the DIFF transmitter needs sensors such as in non-limiting examples a radar, a lidar, an image sensor such as a camera, an ultrasonic sensor, etc.

This tertiary information INFc will be used to calculate the said at least one secondary parameter IP2 '.

In a non-limiting embodiment, for each secondary information INFb and tertiary INFc, a message CPM comprises at least one secondary parameter IP2 'associated, namely a confidence level IC2' and / or a precision PR2 'associated.

It will be noted that a CPM message is produced by a direct propagation known as Adhoc. It spreads through a tunnel, bridge, or underground parking.

Thus, the primary vehicle V1 can receive a CPM message even when it passes in a tunnel, under a bridge, or is in an underground parking, namely when the satellite signals are lost.

The broadcast of a CPM message by the transmitter DI FF is carried out via a wireless communication protocol. In non-limiting embodiments, the wireless communication protocol is a 5G or WIFI communication protocol.

Said transmitter DI FF periodically sends said CPM messages. In a non-limiting embodiment, it sends them every 100 milliseconds. In one embodiment, the DI FF transmitter is configured to determine information about objects around it that are within a one kilometer radius.

It will be noted that when the COMU transmission unit receives CPM messages from a plurality of DIFF transmitters, it will receive a plurality of absolute or relative positions POS2 'with their said at least one associated secondary parameter IP2'.

Furthermore, in a non-limiting embodiment, said COMU transmission unit is configured to transmit said CPM messages to said electronic control unit ECU (function illustrated in FIG. 1 TX (CPM (INFa, INFb, INFc)). • F nçtj nd dentificatlon

In a non-limiting embodiment, said electronic control unit ECU is configured to identify the CPM messages that correspond to the primary vehicle V1.

In the non-limiting examples of Figures 3a and 3b, the transmitter DI FF is surrounded by five objects 01 to 05 which are here motor vehicles, the object 01 being the primary vehicle V1.

The primary vehicle V1 must be able to retrieve the corresponding CPM messages, that is to say who describe it, from among all the CPM messages broadcast by the transmitter DI FF. It must sort through all the CPM messages it receives. In the nonlimiting examples illustrated in FIGS. 3a and 3b, it indeed receives from the transmitter DI FF the messages CPM which describes it but also those which describe the other objects 02 to 05.

In a non-limiting embodiment, the identification of the CPM messages is performed with at least one of the primary information INFa of said CPM message.

Thus, in a non-limiting example, the identification can be done with the license plate.

Thus, in another nonlimiting example, if the type and / or dimensions in the set of CPM messages except one only correspond to trucks, the primary vehicle V1 will take only the single CPM message which includes a type of vehicle that is a light vehicle.

Thus, in another nonlimiting example, if the speed and / or heading, and / or acceleration in a CPM message is substantially equal to that of the primary vehicle V1 over time, the latter can deduce that it is a message CPM corresponding to it. Otherwise, it can classify this CPM message as not describing it and thus not select it.

Note that the identification can be done on a set of CPM messages broadcast by a single transmitter DI FF or a plurality of transmitters DI FF. Thus, the identification of the CPM messages that correspond to said primary vehicle V1 results from the analysis of the multiple CPM messages received over time and coming from one or more DI FF transmitters.

• Determination function _. of POS2 secondary position

In a non-limiting embodiment, said electronic control unit ECU is configured to determine said secondary position POS2 and said at least one secondary parameter IP2 associated.

The secondary position POS2 thus corresponds to the actual POSr position of the primary vehicle V1 or is closest to the said actual position POSr with an error margin better than that of the primary position POS1.

The determination is made from at least a portion of said CPM messages identified as corresponding to said primary vehicle V1 which has been sent by one or more transmitters DI FF.

Said POS2 secondary position and said at least one associated secondary parameter IP2 are thus determined from secondary information INFb of said identified CPM messages.

Thus, the POS2 secondary position is:

determined from the absolute position of the transmitter DI FF and from the relative position of the primary object V1 in the reference centered on the transmitter DI FF making it possible to deduce an absolute position POS2 'of the primary object V1; or

determined from the absolute position POS2 'of the primary object V1 in the common repository.

When it has several CPM sent by several transmitters DI FF, the secondary position POS2 is determined from the set of absolute positions POS2 'received. In a non-limiting example, the secondary position POS2 'is equal to the center of gravity of all the absolute positions POS2' given in the identified CPMs. Similarly, said at least secondary parameter IP2 is determined from the set of secondary parameters IP2 'associated with the absolute positions POS2' received.

When the secondary parameter IP2 is a confidence level IC2, in non-limiting embodiments, the confidence level IC2 is determined from: - 1) tertiary information INFc, from the detection capabilities / sensor types of the transmitter (s) DI FF that detected the primary vehicle V1 and their quality / error rate) indicated in the identified CPM messages; and or

- 2) on the number of different sources of CPM messages identified, namely the number of transmitters DI FF; and or

- 3) on the number of identified CPM messages received over time; and or

- 4) on a cyber attack risk assessed by the electronic control unit ECU ("corrupted CPM message"); and or

- 5) on the coherence (in time) and the plausibility of the INF information received, evaluated by ECU (for example, a car detected by the transmitter DI FF does not disappear suddenly in the middle of the highway); and or

6) primary information INFa, secondary INFb, tertiary INFc. In a non-limiting example, we give a weight to each of these criteria 1) to 6) and we sum it to determine the level of confidence.

It will be noted that the calculated level of confidence IC2 reflects the reliability to be accorded to the determined POS2 secondary position.

When the secondary parameter IP2 is a precision level PR2, in non-limiting embodiments, the accuracy level PR2 is determined from the accuracy levels PR2 'of the INF information mentioned in the CPM messages, for example, the accuracy on measuring the absolute position of the transmitter. Thus, in non-limiting embodiments, the precision level PR2 corresponds to:

at the barycentre of the precision information PR2 'on at least one secondary information INFb, and / or tertiary INFc given, between several messages CPM sent by different transmitters DI FF. These have different detection capabilities, and therefore different precision capabilities; or

at the barycentre of precision information PR2 'on at least one INFb secondary information, and / or tertiary information INFc given between several CPM messages issued by the same DI FF transmitter over time; or

at worst, precision information PR2 'on at least one secondary information INFb, and / or tertiary IN Fc data deduced from the CPM messages sent by all the DIFF transmitters.

• Function _. synchronization

In a nonlimiting embodiment, said locating unit LOCU is configured to synchronize said primary position POS1 with said secondary position POS2 as a function of a comparison between said at least one secondary parameter IP2 and a threshold TH.

Thus, in a nonlimiting embodiment, said locating unit LOCU is further configured to perform a comparison between said at least one secondary parameter IP2 and at least one TH threshold (function illustrated in FIG. 1 COMP (DISP, IP2 , TH)).

In a non-limiting embodiment, said at least one threshold TH is said at least one primary parameter IP1.

As illustrated in FIG. 1, when the primary vehicle V1 loses its satellite coverage (it passes in a tunnel, under a bridge, or it is in an underground car park, etc.), the current POS1 primary position (illustrated POS1 (t) in Figure 1) is different from the actual POSr position of the primary vehicle V1 when there is an extrapolation.

In another case, when the primary vehicle V1 loses its satellite coverage (it passes in a tunnel, under a bridge, or it is in an underground car park, etc.), the current POS1 primary position is no longer available. In non-limiting embodiments, the primary position POS1 is synchronized with the secondary position POS2 at a given time t + 1, namely the primary position POS1 is reset with the secondary position POS2, if at time t1:

the primary position POS1 is unavailable and the said at least one secondary parameter IP2 is greater than or equal to a threshold TH (by for example, the secondary confidence level IC2 and the secondary accuracy level PR2 are greater than or equal to a respective secondary threshold (which can be respectively the primary confidence level IC1 and the primary precision level PR1 in a non-limiting example); or

the secondary precision level PR2 is greater than or equal to threshold TH (which may be the primary precision level PR1 in a non-limiting example) and the secondary confidence level IC2 is greater than or equal to a given threshold (which may be the primary confidence level IC1 in a non-limiting example);

if the secondary confidence level IC2 is greater than or equal to a threshold TH (which may be the primary confidence level IC1 in a nonlimiting example) and the primary accuracy level PR1 is below a given threshold.

Thus, in these non-limiting cases, the value of the primary position POS1 is replaced with the value of the secondary position POS2; otherwise, there is no synchronization.

Thus, if the secondary position POS2 is better than the primary position POS1 at time t, said secondary position POS2 is retained rather than the primary position POS1, and is used to improve the computation performance of the primary POS1 positions, namely at the instant t + 1.

In particular :

if the accuracy of the primary position POS1 calculated at time t by the inertial navigation device INS deteriorates more and more (in a tunnel, underground car park, etc.), said inertial navigation device INS extrapolates a new position primary POS1 from the secondary position POS2 held at time t + 1 when the latter is better than said primary position POS1 extrapolated. This makes it possible to eliminate the drift of the error in the extrapolation of the inertial navigation device INS. It will be noted that in a manner known to those skilled in the art, the extrapolation is calculated from a known position previous and acceleration measurements and / or speed and / or rotation by adding each time an error (which cumulates so);

if the primary position POS1 is lost at a time t, the location unit LOCU directly uses the secondary position POS2 instead of the primary position POS1 at time t + 1 for the functions requiring the primary position POS1 (functions help with driving, navigation etc.).

Thus, as the secondary position POS2 is better than the primary position POS1 at time t + N (N whole), said primary position POS1 is replaced by said secondary position POS2 at time t + N + 1.

Note that it is the primary vehicle V1 itself which deduces its position in the CPM messages and makes the decision to synchronize its primary position POS1 with said POS2 secondary position.

• PR method

FIG. 7 illustrates a time diagram of a synchronization method PR implemented by the synchronization device DISP described above, according to one nonlimiting embodiment.

The different elements of the synchronization device DISP (COMU transmission unit, ECU electronic control unit, LOCU location unit) which participate in the steps of the synchronization method PR are described below.

In this nonlimiting embodiment illustrated:

the transmitter DIFF is another motor vehicle, namely here the secondary vehicle V2.

- the synchronization is performed during the execution of a driver assistance function;

the threshold TH for the comparison is said at least one primary parameter IP1 including a primary confidence level IC1 and a primary precision level PR1.

In a non-limiting embodiment, the PR method is executed when: - the satellite coverage is lost, ie the satellite signals are lost;

the satellite signals include a bad signal-to-noise ratio;

- when the satellite signals are reflected.

In a previous step 0), the location unit LOCU determined the primary position POS1 of the primary vehicle V1 and said at least one associated primary parameter IP1 (by extrapolation or not).

In step 1 '), the COMU transmission unit receives CPM messages broadcast by the secondary vehicle V2 in step 1) and sends them to the electronic control unit ECU in step 1 "). The CPM messages comprise the primary information INFa, secondary INFb and tertiary INFc described above.

In step 2), the electronic control unit ECU filters the received CPM messages. It identifies the CPM messages that correspond to the primary vehicle V1 and retrieves them.

In step 3), from said identified CPM messages, in particular INF information that they contain, the ECU electronic control unit determines a secondary position POS2 and said at least one associated secondary parameter IP2.

In step 4), the location unit LOCU compares said at least one secondary parameter IP2 with said threshold TH which is said at least one primary parameter IP1.

In the non-limiting embodiment, the secondary confidence level IC2 is greater than the primary confidence level IC1 and the secondary accuracy level PR2 is greater than the primary accuracy level PR1. The secondary position POS2 thus has better reliability and better accuracy than the primary position POS1.

In step 5), the location unit LOCU synchronizes said primary position POS1 with said secondary position POS2. That is, it updates the value of the primary position POS1 at time t + 1 with the value of the secondary position POS2 determined at time t. This new value is going thus be used for driving assistance functions for example.

It should be noted that steps 1 to 5 are executed in real time and are repeated over time.

Note that what has been described in this embodiment with the secondary vehicle V2 can be applied for the base transmission station BS.

Of course, the description of the invention is not limited to the application, the embodiments and the examples described above. Thus, in another non-limiting embodiment, the other mobile object V2 is a truck, a motorcycle, a bicycle, a boat, etc.

Thus, in another non-limiting embodiment, the mobile object V1 is a truck, a motorcycle, a bicycle, a boat, etc.

Thus, in another non-limiting embodiment, the fixed infrastructure BS is a marine infrastructure.

Thus, in other non-limiting embodiments, the broadcast of a CPM message by the transmitter DI FF is performed via a wireless communication protocol 3G / 4G / XG or Bluetooth ™.

Thus, in another non-limiting embodiment, the primary position POS1 can be replaced by a primary speed, a primary acceleration, or a primary heading of the moving object V1 because these data are also calculated by the locating unit LOCU. . For this purpose, a secondary speed, a secondary acceleration, a secondary heading can be determined from the CPM messages as well as at least one associated secondary parameter IP2 as described for the secondary position POS2. Finally, in the same way, a synchronization of the primary velocity, the primary acceleration, and / or the primary heading can be performed according to a comparison of their secondary parameter with a threshold.

Thus, in another non-limiting embodiment, the secondary electronic control unit ECU is configured to synchronize said primary position POS1 with said secondary position POS2. Thus, in another non-limiting embodiment, the secondary electronic control unit ECU is configured to make a comparison between said at least one secondary parameter IP2 and at least one threshold TH.

Thus, the described invention has the following advantages in particular: it is simple to implement;

it makes it possible to improve the navigation quality of the primary vehicle V1, in particular for driving assistance or navigation functions;

it makes it possible to correct the error drifts during the extrapolation made by an inertial navigation device INS of the locating unit LOCU when such an inertial navigation device INS is used;

it makes it possible to obtain a more precise position of the primary vehicle V1, especially in the event of loss of satellite coverage;

it makes the driving assistance or navigation functions always operational.

Claims

1. Device for synchronizing (DISP) a primary position (POS1) of a mobile object (V1), at least one primary parameter (IP1) being associated with said primary position (POS1), according to which said synchronization device (DISP) is configured for:

- receive cooperative perception messages (CPM) broadcast by at least one transmitter (DIFF);

from at least part of said received cooperative perception messages (CPM), determining a secondary position (POS2) of said mobile object (V1) and at least one associated secondary parameter (IP2);

synchronizing said primary position (POS1) with said secondary position (POS2) according to a comparison of said at least one secondary parameter (IP2) with at least one threshold (TH).

2. synchronization device (DISP) according to claim 1, wherein said primary position (POS1) is a geolocated position.

3. synchronization device (DISP) according to claim 1, wherein said primary position (POS1) is determined from an extrapolation of a geo-localized position (POST).

4. synchronization device (DISP) according to any one of claims 1 to 3, wherein said at least one threshold (TH) is said minus a primary parameter (IP1).

The synchronization device (DISP) according to any one of claims 1 to 4, wherein:

said at least one primary parameter (IP1) is a level of primary trust or primary level of accuracy; and

said at least one secondary parameter (IP2) is a secondary confidence level or a secondary precision level.

The synchronization device (DISP) according to any one of claims 1 to 5, wherein said synchronization device (DISP) comprises:

a transmission unit (COMU) configured to receive said cooperative perception messages (CPM);

an electronic control unit (ECU) configured to determine said secondary position (POS2) and said at least one associated secondary parameter (IP2);

a locating unit (LOCU) configured to synchronize said primary position (POS1).

The synchronization device (DISP) according to claim 6, wherein said locating unit (LOCU) is further configured to determine said primary position (POS1) of said mobile object (V1) and at least one associated primary parameter (IP1). .

8. synchronization device (DISP) according to any one of claims 1 to 7, wherein said transmitter (DI FF) is part of another mobile object (V2) or another stationary object (BS).

9. synchronization device (DISP) according to claim 8, wherein said other mobile object (V2) is a vehicle or a mobile phone.

The synchronization device (DISP) according to claim 8, wherein said other stationary object (BS) is a fixed infrastructure.

1 1. A synchronization device (DISP) according to any one of claims 1 to 10, wherein said synchronization device (DISP) is further configured to identify the cooperative perception messages (CPMs) that correspond to said mobile object (V1).

12. synchronization device (DISP) according to any one of claims 1 to 11, wherein said locator unit (LOCU) comprises a satellite navigation system (GNSS).

13. Synchronization device (DISP) according to any one of claims 1 to 12, wherein said locating unit (LOCU) further comprises an inertial navigation device (INS).

The synchronization device (DISP) according to any one of claims 1 to 13, wherein said synchronization device (DISP) is configured to receive cooperative perception messages (CPM) broadcast by a plurality of transmitters (DIFF). .

15. synchronization device (DISP) according to any one of claims 1 to 14, wherein said synchronization device (DISP) is part of said moving object (V1).

16. A method for synchronizing (PR) a primary position (POS1) of a moving object (V1), at least one primary parameter (IP1) being associated with said primary position (POS1), comprising:

- the reception of cooperative perception messages (CPM) broadcast by at least one transmitter (DIFF);

from at least part of said cooperative perception messages (CPM), determining a secondary position (POS2) of said mobile object (V1) and at least one associated secondary parameter (IP2);

the synchronization of said primary position (POS1) with said secondary position (POS2) as a function of a comparison of said at least one secondary parameter (IP2) with at least one threshold (TH).