Secondary node location device for a vehicle

Abstract

The invention relates to a device for locating secondary nodes of a vehicle, comprising a primary node and secondary nodes connected together via at least one wired subnetwork, characterized in that: (a) - the primary node is configured to be connected to said at least one wired subnetwork and comprises: - a primary electronic control unit configured, during a learning phase, to: - send activation messages to the secondary nodes to switch their secondary switch, - send inventory broadcast messages to the secondary nodes to determine their presence on said at least one wired subnetwork, - receive presence messages from said secondary nodes comprising a unique identifier associated with each secondary node, (b) - each secondary node comprises: (i) - a secondary electronic control unit configured, during said learning phase, to: - control a secondary switch,- receive from said primary node an activation message to switch its secondary switch, - receive from said primary node an inventory broadcast message to determine its presence on said at least one wired subnet, - send to said primary node a presence message, (ii) - said secondary switch configured so that during said learning phase it takes a primary position in which said secondary node is connected to a previous node that is a secondary node or said primary node, and a secondary position in which said secondary node is connected to a subsequent secondary node if a subsequent secondary node exists.

Description

Title of the invention: Device for locating secondary nodes of a vehicle

[0001] The present invention relates to a device for locating secondary nodes of a vehicle. It finds a particular but non-limiting application in motor vehicles.

[0002] In the field of motor vehicles, a device for locating secondary nodes known to those skilled in the art comprises a main node and a plurality of secondary nodes connected to said main node via at least one wired subnetwork, all of the secondary nodes, said main node and said at least one wired subnetwork forming the vehicle network. The secondary nodes have different positions in the motor vehicle. The main node is configured to send location messages to the different secondary nodes and to receive their responses. Each secondary node is configured to send a response that includes a distance measurement between itself and a hands-free access device. From said distance measurements, the main node can make a geometric reconstruction (such as a triangulation) and thus determine the position of the hands-free access device relative to the motor vehicle.The hands-free access device allows in particular to carry out a function called PEPS (Passive Entry Passive Start). This PEPS function allows the unlocking of the motor vehicle when the hands-free access device approaches the vehicle, and thus allows access to said vehicle, and also authorization to start the motor vehicle.

[0003] Following the determination of the position of the hands-free access device, the PEPS function is authorized or not, or any other function using the hands-free access device such as starting the motor vehicle itself.

[0004] When producing secondary nodes in the factory, a unique identifier is associated with each secondary node.

[0005] One problem is to retrieve the unique identifiers of each secondary node and associate them with each position of the secondary nodes. By correctly identifying the different secondary nodes with respect to their position, the primary node can distinguish the different messages sent by the different nodes on the wired subnetwork and retrieve the distance measurement in a message sent by a secondary node while knowing from which secondary node this distance measurement comes. The primary node can then correctly perform the geometric reconstruction to locate the hands-free access device.

[0006] In this context, the present invention aims to propose a device for locating secondary nodes of a vehicle which makes it possible to solve the mentioned problem.

[0007] To this end, the invention proposes a device for locating secondary nodes of a vehicle, said locating device comprising a main node and secondary nodes connected together via at least one wired subnetwork, characterized in that: (a) - the main node is configured to be connected to said at least one wired subnetwork and comprises: - a main electronic control unit configured for during a learning phase: - send activation messages to secondary nodes to switch their secondary switch, - sending inventory broadcast messages to the secondary nodes to determine the presence of a secondary node on said at least one wired subnetwork, - receiving presence messages from said secondary nodes, said presence message comprising a unique identifier associated with each secondary node, (b)- each secondary node comprises: (i)- a secondary electronic control unit configured to, during said learning phase: - control a secondary switch, - receive from said primary node an activation message to switch its secondary switch, - receive from said main node an inventory broadcast message to determine its presence on said at least one wired subnetwork, - send to said main node a presence message including a unique identifier, (ii)- said secondary switch configured to, during said learning phase, take a primary position in which said secondary node is connected to a previous node which is a secondary node or said primary node, and a secondary position in which said secondary node is connected to a following secondary node if there is a following secondary node.

[0008] Thus, as we will see in detail later, the main node will be able to recover the unique identifier of each secondary node of a wired subnetwork by connecting itself to said secondary nodes as it goes along. By the set of switchings of the secondary switches of the secondary nodes, the main node will ask the secondary node that it has identified to connect it to a following unknown secondary node, namely one whose unique identifier it does not yet know.

[0009] According to non-limiting embodiments, said location device may further comprise one or more additional characteristics taken alone or in all technically possible combinations, among the following.

[0010] According to a non-limiting embodiment, each secondary node further comprises a secondary resistor and in the primary position of said secondary switch said at least one wired sub-network is connected to said secondary resistor, and in the secondary position of said secondary switch said at least one wired sub-network is disconnected from the secondary resistor.

[0011] According to a non-limiting embodiment, said main node further comprises at least one main resistor.

[0012] According to a non-limiting embodiment, said at least one main resistor and said secondary resistors have the same value.

[0013] According to a non-limiting embodiment, the connection of said main node to said at least one subnetwork is permanent.

[0014] According to a non-limiting embodiment, the connection of said main node to said at least one subnetwork is carried out by said main electronic control unit which is configured to control two main switches including: - a first main switch for, during said learning phase, taking a secondary position in which said main node is connected to said at least one wired subnetwork, and - a second main switch for, during said learning phase, taking a primary position in which said at least one sub-network is connected to a main resistor.

[0015] According to a non-limiting embodiment, said main node and the secondary nodes are connected together via a single wired subnetwork and said main electronic control unit is configured to control: - the first main switch to take a secondary position during said learning phase in which said main node is connected to said single wired subnetwork, and - the second main switch for, during said learning phase, taking a primary position in which said single sub-network is connected to a main resistor.

[0016] According to a non-limiting embodiment, said main node and said secondary nodes are connected together via at least two wired sub-networks and said main electronic control unit is configured to control: - the first main switch for, during said learning phase, taking a secondary position in which said main node is connected to said first wired sub-network, and a primary position in which said second wired sub-network is connected to a second main resistor, - the second main switch for, during said learning phase, taking a secondary position in which said first wired sub-network is connected to a first main resistance, and a primary position in which said main node is connected to said second wired sub-network.

[0017] According to a non-limiting embodiment, during an operating phase, said main node is configured to control the two main switches in the primary position to connect the main electronic control unit to said two corresponding wired sub-networks.

[0018] According to a non-limiting embodiment, said secondary nodes are beacons.

[0019] According to a non-limiting embodiment, said primary node uses an identifier derived from the unique identifier of a secondary node to send an activation message to said secondary node.

[0020] According to a non-limiting embodiment, during said operating phase, said secondary nodes are configured to carry out a distance measurement between themselves and a hands-free access device.

[0021] According to a non-limiting embodiment, when the main electronic control unit controls the first main switch in its secondary position, it simultaneously controls the second main switch in its primary position, and vice versa.

[0022] According to a non-limiting embodiment, the main electronic control unit is further configured to: - send a distance measurement request to a secondary node, - measuring the position of the hands-free access device relative to the vehicle based on a plurality of distance measurements of secondary nodes of said hands-free access device.

[0023] According to a non-limiting embodiment, the wired subnetwork is a CAN, LIN, LAN, I2C, or UART network.

[0024] According to a non-limiting embodiment, the secondary nodes are configured to communicate with said hands-free access device according to a UWB (“Ultra Wide Band” in English) communication protocol.

[0025] There is further provided a method for locating secondary nodes of a vehicle, said vehicle comprising a main node and secondary nodes connected together via at least one wired subnetwork, characterized in that said locating method comprises a learning phase comprising the steps of: - send by a secondary electronic control unit of a secondary node a presence message including a unique identifier, - receive by a main electronic control unit of said main node said presence message of said at least one secondary node, - memorize by said main electronic control unit said unique identifier of said at least one secondary node, - sending by said main electronic control unit to said at least one secondary node an activation message to switch an associated secondary switch except when it is the last secondary node of said at least one wired subnetwork, - receive by said secondary electronic control unit from said at least one secondary node said activation message, - switching by said secondary electronic control unit said secondary switch into a secondary position in which said secondary node is connected to a next secondary node if there is a next secondary node.

[0026] According to a non-limiting embodiment, said location method further comprises a step of controlling by said main electronic control unit of said main node a main switch in secondary position to connect said main node to said at least one wired subnetwork.

[0027] There is further provided a method for locating secondary nodes of a vehicle, said vehicle comprising a main node and secondary nodes connected together via at least one wired subnetwork, characterized in that said locating method comprises a learning phase comprising the steps of: - sending by a main electronic control unit of said main node an inventory broadcast message to said secondary nodes of said at least one wired subnetwork, - upon receipt of said inventory broadcast message, send by a secondary electronic control unit of a secondary node a presence message comprising a unique identifier, - receive by said main electronic control unit said message of presence of said at least one secondary node, - memorize by said main electronic control unit said unique identifier of said at least one secondary node, - sending by said main electronic control unit to said at least one secondary node an activation message to switch a secondary switch of said at least one secondary node, - receive by said secondary electronic control unit from said at least one secondary node said activation message, - switching by said secondary electronic control unit said secondary switch into a secondary position in which said secondary node is connected to a next secondary node if there is a next secondary node.

[0028] According to a non-limiting embodiment, said location method further comprises a step of controlling by said main electronic control unit of said main node at least one main switch in secondary position to connect said main node to said at least one wired subnetwork.

[0029] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures:

[0030] [Fig-1] is a schematic view of a secondary node locating device of a vehicle, the location device comprising a main node and at least one secondary node connected to each other by at least one wired subnetwork, the schematic view illustrating said main node, a single secondary node, and a wired subnetwork connecting said main node to said secondary node, according to a non-limiting embodiment of the invention,

[0031] [Fig.2] is a schematic top view of a vehicle illustrating an example of positioning of the main node and several secondary nodes of the location device of [Fig.l], according to a non-limiting embodiment,

[0032] [Fig.3] is a schematic view of the architecture of the main node of said device of location of [Fig.l], according to a first non-limiting embodiment,

[0033] [Fig.4] is a schematic view of the architecture of the main node of said device of location of [Fig.l], according to a second non-limiting embodiment,

[0034] [Fig.5] is a schematic view of the architecture of the main node of said device of location of [Fig.l], according to a third non-limiting embodiment,

[0035] [Fig.6] is a schematic view of the architecture of a secondary node of said locating device of [Fig.l], according to a non-limiting embodiment,

[0036] [Fig.7] is a schematic view of the locating device of [Fig.l], said location device comprising said main node of [Fig.5], seven secondary nodes connected to said main node by a first wired subnetwork and a second wired subnetwork, according to a non-limiting embodiment,

[0037] [Fig.8] is a schematic view of the main node of said locating device of [Fig.7], when it is connected to a first wired subnetwork during a learning phase, according to a non-limiting embodiment,

[0038] [Fig.9] is a schematic view of a secondary node of said device of location of [Fig.7], when connected to a previous node during the learning phase, according to a non-limiting embodiment,

[0039] [Fig. 10] is a schematic view of the secondary node of said location device of [Fig.7], when it is connected to a following secondary node during a learning phase unless it is the last of said wired subnetwork, according to a non-limiting embodiment,

[0040] [Fig. 11] is a schematic view of the location device of [Fig.7], which illustrates the connection of the main node of [Fig.8] to a first secondary node via the first wired subnetwork, according to a non-limiting embodiment,

[0041] [Fig. 12] is a schematic view of the location device of [Fig.7], which illustrates the connection of said first secondary node to a second secondary node via the first wired subnetwork, according to a non-limiting embodiment,

[0042] [Fig. 13] is a schematic view of the location device of [Fig.7], which illustrates the connection of said second secondary node to a third secondary node via the first wired subnetwork, according to a non-limiting embodiment,

[0043] [Fig. 14] is a schematic view of the location device of [Fig.7], which illustrates the connection of said third secondary node to a fourth secondary node via the first wired subnetwork, according to a non-limiting embodiment,

[0044] [Fig. 15] is a schematic view of the main node of said location device of [Fig.7], when it is connected to a second wired subnetwork during the learning phase, according to a non-limiting embodiment,

[0045] [Fig. 16] is a schematic view of the location device of [Fig.7], which shows the connection of the primary node of [Fig. 15] to a fifth secondary node via the second wired subnetwork, according to a non-limiting embodiment,

[0046] [Fig. 17] is a schematic view of the location device of [Fig.7], which shows the connection of said fifth secondary node to a sixth secondary node via the second wired subnetwork, according to a non-limiting embodiment,

[0047] [Fig. 18] is a schematic view of the location device of [Fig.7], which shows the connection of said sixth secondary node to a seventh secondary node via the second wired subnetwork, according to a non-limiting embodiment,

[0048] [Fig. 19] is a schematic view of said main node of said location device of [Fig.7], when it is connected to the first wired subnetwork and to the second wired subnetwork during an operating phase, according to a non-limiting embodiment,

[0049] [Fig.20] is a flowchart of a first method for locating secondary nodes of a vehicle according to a first non-limiting embodiment, said first locating method being implemented by said locating device of [Fig.l],

[0050] [Fig.21] is a flowchart of a first method of locating nodes secondary of a vehicle according to a second non-limiting embodiment, said first location method being implemented by said location device of [Fig.l],

[0051] [Fig.22] is a flowchart of a second method of locating nodes secondary devices of a vehicle according to a first non-limiting embodiment, said second location method being implemented by said location device of [Fig.l],

[0052] [Fig.22] is a flowchart of a second method of locating nodes secondary devices of a vehicle according to a second non-limiting embodiment, said second location method being implemented by said location device of [Fig.l],

[0053] Identical elements, by structure or by function, appearing in different figures retain, unless otherwise specified, the same references.

[0054] In the description, balancing means electrical balancing by means of a load (otherwise called resistance). In the description, a wired sub-network Nw is otherwise called sub-network Nw.

[0055] The device 1 for locating secondary nodes 11 of a vehicle 2 according to the invention is described with reference to FIGS. 1 to 19. In a non-limiting embodiment, the vehicle 2 is a motor vehicle. By motor vehicle is meant any type of motorized vehicle. This embodiment is taken as a non-limiting example in the remainder of the description. In the remainder of the description, the vehicle 2 is thus otherwise called motor vehicle 2.

[0056] The secondary nodes 11 are used to determine the position of a hands-free access device 3 (illustrated in [Fig.2]) relative to the motor vehicle 2. Each secondary node 11 is configured to perform a distance measurement between itself and said hands-free access device 3. In non-limiting embodiments, the hands-free access device 3 is a Smartphone or a hands-free identifier.

[0057] When approaching said hands-free access device 3 of the motor vehicle 2, at least one hands-free function F can be executed. In non-limiting embodiments, the hands-free function F is: - a function called PEPS (“Passive Entry Passive Start” in English). This PEPS function allows in particular the unlocking of the motor vehicle when the hands-free access device 3 approaches the motor vehicle 2, and thus allows access to said vehicle, and also allows authorization to start the motor vehicle 2, or - a welcome scenario function in which lights or projectors of the motor vehicle 2 illuminate a certain so-called welcome area, or - an automatic parking function (otherwise called “Remote Parking” in English).

[0058] In a non-limiting embodiment, the hands-free access device 3 can combine several hands-free functions F.

[0059] The locating device 1 comprises: - a main node 10, - a plurality of secondary nodes 11, - at least one wired subnetwork Nw, otherwise called Nw subnetwork.

[0060] In [Fig. 1], a single secondary node 11 has been shown. In non-limiting embodiments, said at least one wired subnetwork Nw is a CAN, LIN, LAN, I2C or UART network or any other type of network. As can be seen in [Fig. 3] and the following figures, a wired subnetwork Nw is wired on two paths. The main node 10, the secondary nodes 11 and said at least one wired subnetwork Nw form a vehicle network. In a non-limiting embodiment, this vehicle network is a secondary vehicle network different from the main vehicle network used by the electronic control unit (not shown) which controls the engine control or which authorizes the starting of the motor vehicle 2.

[0061] As illustrated in [Fig.7], the secondary nodes 11 are connected to each other and to the main node 10 via said at least one wired subnetwork Nw. They are connected in series. Therefore, one or two secondary nodes 11 are connected directly to the main node 10, while the other secondary nodes 11 are connected indirectly to the main node 10 via other secondary nodes 11.

[0062] In a non-limiting embodiment, the secondary nodes 11 are beacons, otherwise called anchors or satellites. A secondary node 11 is configured to measure its distance relative to the hands-free access device 3. The main node 10 is configured to, from said distance measurements, make a geometric reconstruction (such as a triangulation in a non-limiting example) and thus determine the position PosO of the hands-free access device 3 relative to the motor vehicle 2.

[0063] In a non-limiting example illustrated in [Fig. 2], the main node 10 is arranged at the dashboard of the motor vehicle 2. It will be noted that the main node 10 initially knows the position Posl of the secondary nodes 11, namely the architecture or topology of the vehicle network. In a non-limiting example illustrated in [Fig. 2], the vehicle network comprises seven secondary nodes 11 i to 117. In a non-limiting embodiment illustrated in [Fig. 2], the secondary nodes 11 i to 117 are arranged respectively at the following positions: right front, left front, right front door, left front door, right rear door, left rear door, center of the trunk / tailgate.

[0064] In a non-limiting embodiment, the secondary nodes 11 are configured to communicate with the hands-free access device 3 according to an ultra-wideband communication protocol otherwise known as the UWB protocol (“Ultra Wide Band” in English). This allows a very short communication time between them. In addition, this communication protocol is difficult to hack.

[0065] In a first non-limiting embodiment, the vehicle network comprises a single wired sub-network Nw which is then simply called wired network Nw. In this case, the main node 10 is located at one end of the wired network Nw and is directly connected to a single secondary node 11.

[0066] In a second non-limiting embodiment, the vehicle network comprises two wired sub-networks Nwb Nw2. In this case, the main node 10 is located between these two wired sub-networks Nwb Nw2 and is directly connected to a secondary node 11 on each of the wired sub-networks Nwb Nw2.

[0067] In the non-limiting example of [Fig. 7], the vehicle network comprises two wired sub-networks Nwb Nw2 each comprising respectively four and three secondary nodes 11. Thus, the location device 1 comprises seven secondary nodes 111 to 117 and the main node 11 is located relatively at the center of the vehicle network. The four secondary nodes 111 to 114 are connected to the main node 10 via the wired sub-network Nwb and the three secondary nodes 115 to 117 are connected to the main node 10 via the wired sub-network Nw2. The secondary node 1 l4 is directly connected to the primary node 10 and the other secondary nodes 113>112 and 111 are indirectly connected to the primary node 10 via the wired subnetwork Nwb. The secondary node 1 l5 is directly connected to the primary node 10 and the other secondary nodes 1 l6> and 117 are indirectly connected to the primary node 10 via the wired subnetwork Nw2.

[0068] As illustrated in [Fig.l], the main node 10 comprises: - a main electronic control unit ECU1, otherwise known as the main control unit ECU1 or main unit ECU1, - an NCI network controller which is the physical electrical and protocol interface between said at least one subnetwork Nw and said main control unit ECU1.

[0069] In a non-limiting embodiment, the main node 10 further comprises: - two main switches Swli, Swl2, and - two corresponding network switching controllers SWCU, SWC12, each switching controller SWCli, SWC12 being the physical electrical and protocol interface between said at least one subnetwork Nw and said corresponding main switch Swli, Sw ^.

[0070] In [Fig.l], a single main switch Swl and a single network switching controller SWC1 have been illustrated. In a non-limiting embodiment, the main node 10 further comprises a rewritable programmable memory Mem, otherwise called Mem memory.

[0071] As illustrated in [Fig.l], each secondary node 11 comprises: - a secondary electronic control unit ECU2, otherwise known as a secondary control unit ECU2 or secondary unit ECU2, - a network controller NC2 which is the physical electrical and protocol interface between said at least one subnetwork Nw and said secondary control unit ECU2, - a secondary switch Sw2, and - a network switching controller SWC2 which is the physical electrical and protocol interface between said at least one subnetwork Nw and said at least one secondary switch Sw2.

[0072] The various elements of the main node 10 and of a secondary node 11 are described in detail below.

[0073] The main node 10 is described below.

[0074] The main node 10 is configured to be connected to at least one wired subnetwork Nw.

[0075] Connection to a wired subnetwork Nw allows messages to circulate on said wired subnetwork Nw via the main node 10. A disconnection prevents messages from circulating via said main node 10.

[0076] In a first non-limiting embodiment illustrated in [Fig. 3], the connection is permanent. When the connection is permanent, there is only one wired subnetwork Nw. In this case, the main node 10 does not include a main switch Swl or a corresponding network switching controller SWC1.

[0077] In a second non-limiting embodiment illustrated in [Fig.4] or [Fig.5], the connection is not permanent and is made via two main switches Swli, Swl2.

[0078] Thus, as illustrated in [Fig.5], a main switch Swl is configured to: - take a secondary position pl2 in which the main node 10 is connected to at least one wired subnetwork Nw (function illustrated in [Fig.l] fl2(Swl, pl2, 10, Nw), - take a primary position pli in which the main node 10 is connected to a main resistance RI (function illustrated in [Fig.l] fl3(Swl, pli, 10, RI).

[0079] In this case, the main electronic control unit ECU1 is configured to control two main switches Swli, Swl2 including: - a first main switch Swli to take a secondary position pl2 during a learning phase phO in which said main node 10 is connected audit at least one wired subnetwork Nw (function illustrated in [Fig.l] fl (ECU 1, Swli, pl2, Nw)), and - a second main switch Swl2 for, during said learning phase phO, taking a primary position pli in which said at least one sub-network Nw is connected to a main resistance RI (function illustrated in [Fig.l] f2(ECUl, Swl2, pli, RI)).

[0080] The learning phase phO makes it possible to identify the secondary nodes 11 with respect to positions Posl of said secondary nodes 11. It thus makes it possible to recover the unique identifiers Id of the different secondary nodes 11. In a non-limiting embodiment, the learning phase phO is triggered in the factory by a tool external to the location device 1. It is explained in detail later in the description.

[0081] In the remainder of the description, the first main switch Swli is otherwise called main switch Swli, and the second main switch Swl2 is otherwise called main switch Swl2.

[0082] When the connection is not permanent, in a first non-limiting variant embodiment illustrated in [Fig.4], the main node 10 and the secondary nodes 11 are connected together via a single wired subnetwork Nw. There is only one wired network Nw. The wired subnetwork Nw forms with said main node 10 and said secondary nodes 11 the vehicle network.

[0083] In this case, said main electronic control unit ECU is configured to control: - the first main switch Swli to take a secondary position pl2 during said learning phase phO in which said main node 10 is connected to said single wired subnetwork Nw, and - the second main switch Swl2 for during said learning phase phO taking a primary position pli in which said single sub-network Nw is connected to a main resistance RL

[0084] When the connection is not permanent, in a second non-limiting embodiment illustrated in [Fig.5], the main node 10 and the secondary nodes 11 are connected together via at least two wired subnetworks Nwb Nw2. The two wired subnetworks Nwb Nw2 form with said main node 10 and said secondary nodes 11 the vehicle network, and each wired subnetwork Nwb Nw2 connects in series one or more secondary nodes 11 to said main node 10. The wired subnetwork Nwi is also called the first wired subnetwork Nwb. The wired subnetwork Nw2 is also called the second wired subnetwork Nw2.

[0085] Thus, in the non-limiting example of [Fig.7] where there are seven secondary nodes 1 li to 117 distributed over two wired subnetworks Nwi and Nw2, the wired subnetwork Nwi comprises the secondary nodes 1 h to 114, the secondary node 1 F being the furthest from the main node 10, and the secondary node 114 being the closest to the main node 10 and connected directly to the main node 10; and the wired subnetwork Nw2 comprises the secondary nodes 115 to 117, the secondary node 1 l7 being the furthest from the main node 10, and the secondary node 115 being the closest to the main node 10 and connected directly to the main node 10.

[0086] In this case, said main electronic control unit ECU1 is configured to control: - the first main switch Swlipour during said learning phase phO takes a secondary position pl2 in which said main node 10 is connected to said first wired subnetwork Nwi (function fl described previously), and takes a primary position pli in which said second wired subnetwork Nw2is connected to a second main resistor Rl2 (function illustrated in [Fig.l] f3(ECUl, Swli, pli, RI)). In this primary position pli, the first main switch Swli is disconnected from the first wired subnetwork Nwb - the second main switch Swl2 to, during said learning phase phO, take secondary position pl2 in which said main node 10 is connected to said second wired subnetwork Nw2 (function illustrated in [Fig.l] f4(ECUl, Swl2, p 12, Nw2)), and take a primary position pl1 in which said first wired subnetwork Nwi is connected to a first main resistor Rli (function f2 described previously). In this primary position pl1, the second main switch Swl2 is disconnected from the second wired subnetwork Nw2.

[0087] In the remainder of the description, the first main resistor Rli is otherwise called main resistor Rli. The second main resistor Rl2 is otherwise called main resistor Rl2.

[0088] Thus, in the case of two sub-networks Nwi, Nw2, the location device 1 comprises two main resistors Rlb Rl2.

[0089] Note that a disconnection means that the main switch Swl has cut off the electrical signal which carries the messages on a wired subnetwork Nw.

[0090] It will be noted that when the main electronic control unit ECU1 controls the first main switch Swli in its secondary position pl2, it simultaneously controls the second main switch Swl2 in its primary position 11. And conversely, when the main electronic control unit ECU1 controls the second main switch Swl2 in its secondary position pl2, it simultaneously controls the first main switch Swli in its primary position 11.

[0091] Thus, as illustrated in [Fig.8], when the main switch Swli is in its secondary position pl2, the main switch Swl2 is in its primary position pl1. In this case, the main node 10 is connected to the wired subnetwork Nwi. It can communicate with the secondary nodes 111 to 114 of the wired subnetwork Nwi. In other words, its main electronic control unit ECU 1 is connected to the wired subnetwork Nwi and can communicate with the secondary electronic control units ECU2 of the secondary nodes 111 to 114. Furthermore, the wired subnetwork Nwi is connected to the first main resistor R1 b. This makes it possible to balance the wired subnetwork Nwi at the value of this first main resistor R1 b. The main node 10 is disconnected from the wired subnetwork Nw2. It cannot communicate with the secondary nodes 115 to 117 of the wired subnetwork Nw2.In other words, its main electronic control unit ECU1 is disconnected from the wired subnet Nw2 and cannot communicate with the secondary electronic control units ECU2 of the secondary nodes 115 to 117.

[0092] As illustrated in [Fig. 15], when the main switch Swl2 is in its secondary position pl2, the main switch Swli is in its primary position pl1. In this case, the main node 10 is connected to the wired subnetwork Nw2. It can communicate with the secondary nodes 115 to 117 of the wired subnetwork Nw2. In other words, its main electronic control unit ECU 1 is connected to the wired subnetwork Nw2 and can communicate with the secondary electronic control units ECU2 of the secondary nodes 115 to 117. Furthermore, the wired subnetwork Nw2 is connected to the second main resistor Rl2. This makes it possible to balance the wired subnetwork Nw2 at the value of this second main resistor Rl2. The main node 10 is disconnected from the wired subnetwork Nwi.It cannot communicate with the secondary nodes 111 to 114 of the wired subnetwork Nwb. In other words, its main electronic control unit ECU1 is disconnected from the wired subnetwork Nwi and cannot communicate with the secondary electronic control units ECU2 of the secondary nodes 111 to 114.

[0093] It will be noted that the same principle applies for N sub-networks Nw, the location device 1 comprising in this case: - N main switches Swl, each associated with a subnetwork Nw and configured to connect the main node 10 to the corresponding subnetwork Nw, in particular during the learning phase phO, - N main resistors RI to balance each of the N sub-networks Nw.

[0094] As illustrated in [Fig.l], the main electronic control unit ECU1 is further configured to during the phO learning phase: - send activation messages msgl to the secondary nodes 11 to switch their secondary switch Sw2 (function illustrated in [Fig.l] f5(ECUl, 11, msgl(Id'), Sw2)), - sending inventory broadcast messages msg2 to the secondary nodes 11 to determine the presence of a secondary node 11 on said at least one wired subnetwork Nw (function illustrated in [Fig.l] f6(ECUl, 11, msg2)), - receiving a presence message msg3 from said secondary nodes 11, said presence message msg3 comprising a unique identifier Id associated with each secondary node 11 (function illustrated in [Fig.l] f7(ECUl, 11, msg3(Id))).

[0095] It will be noted that an activation message msgl is thus addressed to a single secondary node 11, while an inventory broadcast message msg2 is addressed to all the secondary nodes 11 of the vehicle subnetwork Nw concerned. In a non-limiting embodiment, the main node 10 uses an identifier Id' derived from the unique identifier Id of a secondary node 11 to send the activation messages msgl to said secondary node 11. Furthermore, either the presence message msg3 is a broadcast message, namely addressed to any node on the subnetwork Nw, or it is a dedicated message addressed directly to the main node 10, which consequently includes the unique identifier of said main node 10. Thus, either the secondary nodes 11 do not know the unique identifier of said main node 10, or they do.

[0096] It will be noted that for good communication between the different nodes 10 and 11 of a vehicle network, good electrical balancing of this vehicle network is required. The wired subnetworks Nw of the vehicle network have a long wire length. If we want the communication between the different nodes 10 and 11 to be optimal, each wired subnetwork Nw must be balanced, otherwise there is a risk of having degraded communication between the different nodes 10 and 11. If a wired subnetwork Nw is not balanced, there is a risk of having an attenuated signal during the transmission of the unique identifier Id. The main node 10 thus risks not receiving the presence messages msg3 and their content, including the unique identifier Id in particular, in particular if the latter comes from the secondary node 11 of the wired subnetwork Nw that is furthest from the main node 10.Indeed, to send its unique identifier Id, a presence message msg3 sent by a secondary node 11 must pass over the wired subnetwork Nw and through all the other secondary nodes 11 located between it and the main node 10. In the same way, a secondary node 12 risks not receiving the activation messages msgl or the broadcast messages. msg2 inventory and not properly retrieve their content, including the message type.

[0097] To balance a wired subnetwork Nw, the amplitude of the electrical signal that carries the messages (msgl, msg2, msg3) must be uniform throughout the wired subnetwork Nw. The wired subnetwork Nw must be loaded in the same way. This means that it must have the same impedance on its right and left. This allows for robust communication between the different nodes 10 and 11 of the wired subnetwork Nw. Balancing a wired subnetwork Nw is done by means of a main resistor RI on one side of the wired subnetwork Nw, and by means of a secondary resistor R2 on the other side of the wired subnetwork Nw.

[0098] For this purpose, in a non-limiting embodiment, the main node 10 further comprises at least one main resistor RI for balancing a wired sub-network Nw.

[0099] Thus, in the first non-limiting embodiment illustrated in [Fig.3] where there is only one wired sub-network Nw and no main switch Swl, the main node 10 comprises a single main resistor RI connected to said wired sub-network Nw.

[0100] Thus, in the first non-limiting variant embodiment of the second non-limiting embodiment illustrated in [Fig.4] where there is only one wired sub-network Nw and two main switches Swli and Swl2, the main node 10 comprises a single main resistor RI connected to said wired sub-network Nw when the second main switch Swl2 is in its primary position pli.

[0101] Thus, in the second non-limiting variant embodiment of the second non-limiting embodiment illustrated in [Fig. 5] where the secondary nodes 11 are distributed over two wired sub-networks Nwb Nw2, and where the main node 10 comprises two main switches Swl, Sw2 each connected to a wired sub-network Nwb Nw2, the main node 10 comprises two main resistors Rlb Rl2 each associated with one of the two wired sub-networks Nwb Nw2, one of which Rli is connected to the first wired sub-network Nwj when the second main switch Swl2 is in its primary position pl 1, and the other of which Rl2 is connected to the second wired sub-network Nw2 when the first main switch Swl2 is in its primary position pl. Thus, the main resistance Rli allows the first wired sub-network Nwb to be balanced and the main resistance Rl2 allows the second wired sub-network Nw2 to be balanced.

[0102] It will be noted that the same principle applies for N sub-networks Nw, the location device 1 comprising in this case N main resistors RI, each associated with a sub-network Nw.

[0103] The secondary nodes 11 are now described below.

[0104] As illustrated in [Fig.l], a secondary electronic control unit ECU2 is configured to during said learning phase phO: - control a secondary switch Sw2 (function illustrated in [Fig.l] f8(ECU2, Sw2)), - receive from said main node 10 activation messages msgl to switch its secondary switch Sw2 (function illustrated in [Fig.l] f9(ECU2, 10, msgl(id'), Sw2)), - receiving from said main node 10 inventory broadcast messages msg2 to determine its presence on said at least one wired subnetwork Nw (function illustrated in [Fig.l] flO(ECU2, 10, msg2)), - send to said main node 10 a presence message msg3 including a unique identifier Id (function illustrated in [Fig.l] fll(ECU2, 10, msg3(Id))).

[0105] As illustrated in [Fig.6], said secondary switch Sw2 configured to: - take a primary position p21 in which the secondary node 11 is connected to a previous node which is a secondary node 11 or said primary node 10 (function illustrated in [Fig.l] fl2'(Sw2, p21, 11, 10). The previous secondary node 11 is connected to the output IN of the current secondary node 11, - a secondary position p22 in said secondary node 11 is connected to a following secondary node 11 if there is a following secondary node 11 (function illustrated in [Fig.l] fl3'(Sw2, p22, 11). The following secondary node 11 is connected to the output OUT of the current secondary node 11. If it is the last secondary node 11 of said at least one wired subnetwork Nw there is no following secondary node 11. In this case, in the secondary position 22, it is not connected to any following secondary node 11.

[0106] Connection to a wired subnetwork Nw allows messages to circulate on said wired subnetwork Nw via the secondary node 11. A disconnection prevents messages from circulating via said secondary node 11.

[0107] For balancing the vehicle network, in a non-limiting embodiment, each secondary node 11 further comprises a secondary resistor R2, otherwise called internal resistor R2.

[0108] As illustrated in [Fig.6]: - in the primary position p21 said at least one wired sub-network Nw is connected to the secondary resistance R2 of said secondary node 11, - in the secondary position p22 said at least one wired sub-network Nw is disconnected from the secondary resistance R2.

[0109] Connecting to the secondary resistance R2 allows the sub-network Nw to be balanced on one of its sides. This secondary resistance R2 is that of the node secondary node 11 to which the primary node 10 connects to retrieve the unique identifier Id. In each secondary node 11, the same value of the secondary resistance R2 is propagated.

[0110] Thus, thanks to a main resistance RI of the main node 10 and the secondary resistances R2 of each secondary node 11, a wired sub-network Nw is loaded in the same way at each of its sides and therefore at each of its ends.

[0111] In a non-limiting embodiment, said at least one main resistor RI and the secondary resistors R2 have the same value. Their value is fixed and depends on the type of wired subnetwork Nw implemented. In a non-limiting example, their value is substantially equal to 120Ω (Ohms) for a CAN-type wired subnetwork Nw. Said at least one main resistor RI and the secondary resistors R2 are balancing resistors. Thus, said at least one main resistor RI and secondary resistors R2 make it possible to balance a wired subnetwork Nw as the main node 10 connects to an unknown secondary node 11 (of said at least one wired subnetwork Nw) to recover its unique identifier Id.

[0112] The learning phase phO makes it possible to retrieve the unique identifiers Id of the different secondary nodes 11. In order to know the unique identifier Id of each secondary node 11, the main node 10 connects progressively to the different secondary nodes 11 of a wired subnetwork Nw. When there are two wired subnetworks Nwb Nw2, the main node 10 only connects to one of the two wired subnetworks Nwb Nw2 at a time. It thus disconnects simultaneously from the other wired subnetwork Nw2, Nwb II will thus retrieve the unique identifiers Id of the secondary nodes 11 of the wired subnetwork Nw to which it has connected. Then, when it is finished, it disconnects from this wired subnet Nw and connects to the other wired network Nw to retrieve the unique identifiers Id of the secondary nodes 11 of this other wired subnet Nw.The primary node 10 can connect first to the wired subnet Nwi or to the wired subnet Nw2.

[0113] Thus, in a non-limiting embodiment, during a learning phase PhO, the main node 10 is configured to control a single main switch Swl, Sw2 in the secondary position pl2 to connect the main electronic control unit ECU1 to said corresponding wired subnetwork Nwb Nw2, and to control the other main switch Sw2, Swl in the primary position pl1 to disconnect the main electronic control unit ECU1 from the other corresponding wired subnetwork Nw2, Nwi as seen previously.

[0114] This PhO learning phase is carried out only once when the location device 1 is installed in the motor vehicle 2 at the assembly plant of said vehicle. motor vehicle 2, or in the event of repair or replacement of the main node 10 or the secondary nodes 11 in the car garage for example.

[0115] The main node 10 will gradually connect to the secondary nodes 11 of a wired subnetwork Nw, starting with the secondary node 11 closest to it. It will be noted that initially at the start of the learning phase phO, the secondary switches Sw2 of the secondary nodes 11 are in their primary position p21 as illustrated in [Fig.9].

[0116] Thus, in the non-limiting example illustrated in [Fig. 11], in the case of the seven secondary nodes 111 to 117 distributed over two wired subnetworks Nwi and Nw2, to connect to the wired subnetwork Nwi and disconnect from the wired subnetwork Nw2, the main node 10 controls the main switch Swli in its secondary position pl2 and controls the main switch Swl2 in its primary position pl1. In this case, the first main resistor Rli is connected to the wired subnetwork Nwb which makes it possible to balance the wired subnetwork Nwp

[0117] The main node 10 will gradually connect to the secondary nodes 11 of this wired subnetwork Nwi, starting with the nearest secondary node 11.

[0118] Thus, in the non-limiting example illustrated in [Fig. 11], the primary node 10 connects first to the secondary node 114 only, which thus becomes the current secondary node 11. The secondary node 114 is the closest secondary node 11. The primary node 10 is for the moment disconnected from the following secondary nodes 11, namely nodes 113, 112 and 11b. The primary node 10 can communicate with this secondary node 114 to retrieve its unique identifier Id. Note that the secondary switch Sw2 of the secondary node 114 is in its primary position p21. The secondary resistance R2 of the secondary node 114 makes it possible to balance the wired subnetwork Nwi with the main resistance R1 b

[0119] After having retrieved the unique identifier Id of a secondary node 11, the main node 10 asks it to connect it to the next secondary node 11 whose unique identifier Id it does not yet know.

[0120] To communicate with the next secondary node of a wired subnetwork Nw, the main node 10 sends an activation message msgl to the secondary node 11 to which it is connected to ask it to switch its secondary switch Sw2 to its secondary position p22 as illustrated in [Fig. 10]. The wired subnetwork Nwest in this case disconnected from the secondary resistance R2 of this secondary node 11, but will be connected to the secondary resistance R2 of the next secondary node 11 to keep the wired subnetwork Nw balanced. It will be noted that as it has recovered the unique identifier Id of the current secondary node 11, it can send it this activation message msgl using an identifier Id' derived from this unique identifier Id.

[0121] Thus, in the non-limiting example of the seven secondary nodes 111 to 117 distributed over two wired subnetworks Nwi and Nw2, to communicate with the next secondary node 11 of the wired subnetwork Nwb, namely with the secondary node 113, the main node 10 sends an activation message msgl to the secondary node 114; the latter switches its secondary switch Sw2 to its secondary position p22, and thus connects to the next secondary node 113 as illustrated in [Fig. 12], which becomes the current secondary node 11. The wired subnetwork Nwi is in this case disconnected from the secondary resistance R2 of the secondary node 114, but will be connected to the secondary resistance R2 of the next secondary node 113 to keep the wired subnetwork Nwi balanced. The primary node 10 is thus connected to the secondary node 114, whose unique identifier Id it knows, and to the secondary node 113, whose unique identifier Id it does not yet know.It can then communicate with the secondary node 113 to retrieve its unique identifier Id. Note that since it has retrieved the unique identifier Id of the secondary node 114, it can send it this activation message msgl using an identifier Id' derived from this unique identifier Id.

[0122] Figures 13 and 14 illustrate on the same principle the connection of the main node 10 with the following secondary nodes 11, namely the following secondary nodes 112 and 111, and this up to the last secondary node 11 of the wired subnetwork Nwb, the secondary node 111 being the last node of the wired subnetwork Nwb

[0123] It will be noted that in the primary position p21 of the secondary switch Sw2, a secondary node 11 is connected either to the main node 10 in the case where it is the secondary node 11 closest to the main node 10, or to a previous secondary node 11. Thus, it can be seen that the secondary nodes 114, 113, 112, 111 are respectively connected to the main node 10, and to the secondary nodes 114, 113, and 112.

[0124] Furthermore, in the secondary position p22 of the secondary switch Sw2, a secondary node 11 is connected to a following secondary node 11 if there is a following secondary node 11, except for the last of said wired subnetwork Nw since in this case there is no following secondary node 11. Thus, it can be seen that the secondary nodes 114, 113, 112 are respectively connected to the secondary nodes 113, 112, and 111 while the secondary node 111 is not connected to any following secondary node 11. It will be noted that a following secondary node 11 is a secondary node which moves away from the main node 10 with respect to the current secondary node 11. It will be noted that a previous secondary node 11 is a secondary node that is closer to the primary node 10 than the current secondary node 11.

[0125] After having retrieved the unique identifiers Id of all the secondary nodes 11 of the wired subnetwork Nwb, the main node 10 does the same with the secondary nodes 11 of the other wired subnetwork Nw2.

[0126] As illustrated in [Fig.15], to connect to the wired subnetwork Nw2 and disconnect from the wired subnetwork Nwb, the main node 10 controls the main switch Swl2 in its secondary position pl2 and controls the main switch Swli in its primary position pl1. In this case, the second main resistor Rl2 is connected to the wired subnetwork Nw2j, which makes it possible to balance the wired subnetwork Nw2.

[0127] The main node 10 will gradually connect to the secondary nodes 11 of this wired subnetwork Nw2, starting with the secondary node 11 closest to it.

[0128] Thus, in the non-limiting example illustrated in [Fig. 16], it connects first to the secondary node 115 only, which becomes the current secondary node 11. The secondary node 115 is the closest secondary node 11. The primary node 10 is currently disconnected from the following secondary nodes 11, namely nodes 116 and 117. The primary node 10 can then communicate with this secondary node 115 to retrieve its unique identifier Id. Note that the secondary switch Sw2 of the secondary node 115 is in its primary position p21. The secondary resistance R2 of the secondary node 115 makes it possible to balance the wired subnetwork Nw2 with the primary resistance Rl2.

[0129] After having retrieved the unique identifier Id of a secondary node 11, the main node 10 asks it to connect it to the next secondary node 11 whose unique identifier Id it does not yet know.

[0130] To communicate with the next secondary node 11 of the wired subnetwork Nw2, namely with node 116, the main node 10 sends an activation message msgl to the secondary node 115; the latter switches its secondary switch Sw2 to its secondary position p22, and thus connects to the next secondary node 116 as illustrated in [Fig. 17]. The wired subnetwork Nw2 is in this case disconnected from the secondary resistance R2 of the secondary node 115, but will be connected to the secondary resistance R2 of the next secondary node 116 to keep the wired subnetwork Nw2 balanced. The main node 10 is thus connected to the secondary nodes 115 and 116. It can then communicate with the secondary node 116 to retrieve its unique identifier Id. It will be noted that since it has retrieved the unique identifier Id of the secondary node 115, it can send it this activation message msgl using an identifier Id' derived from this unique identifier Id.

[0131] [Fig.18] illustrates on the same principle the connection of the main node 10 with the following secondary node 117, the secondary node 117 being the last node of the wired subnetwork Nw2.

[0132] It will be noted that in the primary position p21 of the secondary switch Sw2, a secondary node 11 is connected either to the main node 10 in the case where it is the secondary node 11 closest to the main node 10, or to a previous secondary node 11. Thus, it can be seen that the secondary nodes 115, 116, 117 are respectively connected to the main node 10, and to the secondary nodes 115 and 116

[0133] Furthermore, in the secondary position p22 of the secondary switch Sw2, a secondary node 11 is connected to a following secondary node 11 except for the last of said wired subnetwork Nw. Thus, it can be seen that the secondary nodes 115, 116 are respectively connected to the secondary nodes 116, and 117 while the secondary node 117 is not connected to any following secondary node 11.

[0134] It will be noted that the main node 10 only communicates with one unknown secondary node 11 at a time (of a wired subnetwork Nw), namely of which it does not know the unique identifier Id.

[0135] When the main node 10 has retrieved the unique identifiers Id of all the secondary nodes 11 located on the vehicle network, it associates their position Posl with them. The learning phase phO is then completed.

[0136] Thus, the main electronic control unit ECU1 of the main node 10 is further configured to associate a position Posl with the unique identifier Id of each secondary node 11 (function illustrated in [Fig.l] fl4(ECUl, 1 l(Id, Posl)).

[0137] In a first non-limiting embodiment, the main node 10 knows the architecture of the vehicle network, namely it knows the number of secondary nodes 11 of the (when there is only one) or of each of the wired sub-networks Nw of the vehicle network. In this case, the main node 10 knows when to stop the switching of the secondary switches Sw2. In this first non-limiting embodiment, the main node 10 also knows the positions Posl of the secondary nodes 11.

[0138] In a second non-limiting embodiment, the main node 10 does not know the architecture of the vehicle network, namely it does not know the number of secondary nodes 11 of the (when there is only one) or of each of the wired sub-networks Nw of the vehicle network. In this second non-limiting embodiment, the main node 10 knows the positions Posl of the secondary nodes 11 for a determined number of secondary nodes 11. Thus, different configurations cg of positions Posl are saved in memory Mem, according to a number Nb of nodes secondary nodes 11. When it retrieves the number Nb of secondary nodes 11 present on the motor vehicle 2, the main node 10 will thus be able to retrieve the corresponding cg configuration and associate with the unique identifier Id of each secondary node 11 a position Posl saved in this cg configuration. Thus, in a non-limiting embodiment, the main electronic control unit ECU1 is further configured to associate with a number Nb of secondary nodes 11 a cg configuration of positions Posl (function illustrated in [Fig.l] fl5(ECUl, 11, Nb, cg(Posl)).

[0139] When the learning phase phO is completed, the location device 1 can then operate in a phase, called the operating phase phi, in which the main node 10 communicates with all the secondary nodes 11 of the vehicle network, namely with all the secondary nodes 11 of the wired subnetwork(s) Nw. The operating phase phi is triggered in the factory when the learning phase phO is completed. In the operating phase phi, the main node 10 locates the hands-free access device 3 with the help of the secondary nodes 11. This operating phase phi is activated automatically by the main electronic control unit ECU1 when the learning phase phO is completed.

[0140] To activate the operating phase phi, the main node 10 is configured to control all the main switches Swl in their secondary position p 12 to connect the main node 10 to all said corresponding wired subnetworks Nw (function illustrated in [Fig.l] fl6(ECUl, phi, Swl, pl2)). Thus, in the non-limiting example of the seven secondary nodes 11 i to ll7 distributed over two wired subnetworks Nwb Nw2, as illustrated in [Fig. 19], the two main switches Swl 1 and Swl2 are in their secondary position pl2. The main node 10 is thus connected to the two wired subnetworks Nwl and Nw2. In other words, the primary node 10 is connected to the secondary nodes 111 to 114 of the wired subnetwork Nwl, and to the secondary nodes 115 to 117 of the wired subnetwork Nw2. It can communicate with all the secondary nodes 111 to 117.Thus, the main node 10 can request from the secondary nodes 11 distance measurements between said secondary nodes 11 and the hands-free access device 3, retrieve them and measure the position PosO of the hands-free access device 3 according to said distance measurements.

[0141] Thus, in a non-limiting embodiment, the main electronic control unit ECU 1 is further configured to: - send a request msg4 for measuring distance d to a secondary node 11 (function illustrated in [Fig.l] fl7(ECUl, ll,msg4(d)), - measuring the position PosO of the hands-free access device 3 relative to the motor vehicle 2 as a function of a plurality of distance measurements of secondary nodes 11 of said hands-free access device 3 (function illustrated in [Fig.l] fl8(ECUl, 11, d, PosO)). Such a position measurement being known to those skilled in the art, it is not described here.

[0142] Depending on the location of the hands-free access device 3 around the motor vehicle 2, the main electronic control unit ECU1 authorizes or not the PEPS function, or any other hands-free function F described previously.

[0143] Thus, the location device 1 is configured to implement a first location method 5 according to a non-limiting embodiment, otherwise called location method 5. The first location method 5 is implemented when the main node 10 knows the number of secondary nodes 11 in the vehicle network.

[0144] Furthermore, the location device 1 is configured to implement a second location method 6 according to a non-limiting embodiment, otherwise called location method 6. The second location method 6 is implemented when the main node 10 does not know the number of secondary nodes 11 in the vehicle network. This second location method 6 thus makes it possible to make an inventory of the secondary nodes 11 present in the vehicle network.

[0145] The first localization method 5 and the second localization method 6 comprise a learning phase phO and an operating phase phi.

[0146] The location method 5 is described according to a first non-limiting embodiment illustrated in [Fig.20] and according to a second non-limiting embodiment in [Fig.21].

[0147] According to the first non-limiting embodiment illustrated in [Fig.20], there is only one sub-network Nw. In a non-limiting example, this single sub-network Nw comprises seven secondary nodes 111 to 117, the secondary node 111 being the closest to the main node 10 and the secondary node 117 being the furthest away and being the last secondary node 11 of the sub-network Nw.

[0148] Thus, as illustrated in [Fig.20], in the case where there is only one wired sub-network Nw, during the learning phase phO, the following steps are carried out.

[0149] In an illustrated step E1 F1(ECU2, 10, msg3(Id)), the secondary electronic control unit ECU2 of the secondary node 1 returns a presence message msg3 comprising the unique identifier Id of said secondary node 1 lp. By default, the secondary nodes 111 to 117 have their secondary switch Sw2 in the primary position p21. The presence messages msg3 of the secondary nodes 112 to 117 do not go back to the main node 10. Only the presence message msg3 of the secondary node 11 goes back to the main node 10 because it is directly connected to the main node 10 on the subnetwork Nw. The main node 10 thus receives only the unique identifier Id of the first secondary node 11p.

[0150] In a step E2 illustrated F2(ECU1, 11, msg3(Id)), the main electronic control unit ECU1 of the main node 10 receives said presence message msg3 and in a step E3 illustrated F3(ECU1, Mem, Id), stores said unique identifier Id of said secondary node 111 in its memory Mem. In a non-limiting embodiment, the main control unit ECU1 waits for said presence message msg3 for a waiting time equal to 250ms (milliseconds) in a non-limiting example.

[0151] In a step E4 illustrated F4(ECU1, 11, msgl(Id')), the main electronic control unit ECU1 of the main node 10 sends to said secondary node 1 h an activation message msgl so that it switches its secondary switch Sw2, except when it is the last node of said wired subnetwork Nw, which is not the case for the secondary node 11p. The activation message msgl is addressed only to said secondary node 1 h thanks to the derived identifier Id' of said unique identifier Id. It will be noted that for the last secondary node 117, no activation message msgl is sent to it.

[0152] In a step E5 illustrated F5(ECU2, 10, msgl(Id')), the secondary electronic control unit ECU2 of the secondary node 111 receives this activation message msgl, except when it is the last node of said wired subnetwork Nw, which is not the case for the secondary node 1 h.

[0153] In a step E6 illustrated F6(ECU2, Sw2, p22), the secondary control unit ECU2 of the secondary node 111 switches its secondary switch Sw2 to the secondary position p22 in which said secondary node 111 is connected to the next secondary node 112 unless there is no next secondary node 11, which is not the case for the secondary node 111p. This switching causes the wired subnetwork Nw to be disconnected from the secondary resistor R2 associated with said secondary node 11h and is connected to the secondary resistor R2 associated with said next secondary node 112. The main node 10 can then communicate with this next secondary node 112 to retrieve its unique identifier Id. If there is no next secondary node 11, the switching is carried out but there is no connection to a next secondary node 11.

[0154] Steps E1 to E6 are thus repeated with the next secondary node 11 up to the penultimate secondary node 116 of the wired subnetwork Nw. The main electronic control unit ECU1 knows that there are seven secondary nodes 11 for the wired subnetwork Nw. Thus, if there are q secondary nodes 11, there are q-2 repetitions of steps E4 to E6. Steps E1 to E3 are repeated for the last secondary node 117. Thus, if there are q secondary nodes 11, there are q-1 repetitions of steps E1 to E3. Steps E4 to E6 are not executed for the last secondary node 117. secondary switch Sw2 of the last secondary node 1 l7 will always remain in primary position p21.

[0155] When it has retrieved all the unique identifiers Id of each secondary node 11, in a step E7 illustrated F7(ECU1, Id, Posl(ll)), the main electronic control unit ECU1 of the main node 10 associates with them the corresponding positions Posl of the secondary nodes 11. It will be noted that this step can be executed as soon as an identifier Id has been retrieved instead of waiting until all have been retrieved.

[0156] The learning phase PhO is completed. The location device 10 can then operate in its operating phase phi. Thus, in a step E8 illustrated F8(ECU1, phi), the main electronic control unit ECU1 of the main node 10 activates the operating phase phi.

[0157] According to the second non-limiting embodiment illustrated in [Fig. 21], there are two sub-networks Nwb Nw2. In a non-limiting example, the sub-networks Nwb Nw2 each comprise the nodes 111 to 114 and the nodes 115 to 117 respectively. The secondary node 114 and the secondary node 115 are the closest to the main node 10. They are each arranged on either side of the main node 10. The secondary node 111 and the secondary node 117 are the furthest from the main node 10 and are respectively the last secondary node 11 of the sub-network Nwi and of the sub-network Nw2.

[0158] Initially the main switches Swli, Swl2 of the main node 10 are positioned in the primary position p11: the main node 10 is not connected to any wired subnetwork Nwb Nw2. Furthermore, initially, the secondary switches Sw2 of each secondary node 11 are switched to their primary position p21. They are connected to the corresponding secondary resistor R2.

[0159] According to this second non-limiting embodiment, the main node 10 connects first to the subnetwork Nwb. It will be noted that the choice of connecting first to the subnetwork Nwi is random. In a non-limiting embodiment, the choice is configured in the main electronic control unit ECU1 of the main node 10.

[0160] Thus, as illustrated in [Fig.21], in the case where there are two wired sub-networks Nwi, Nw2, during the learning phase phO, the following steps are carried out.

[0161] In a step E0 illustrated F0(ECUl, Swli, pl2, Swl2, pli), the main electronic control unit ECU1 of the main node 10 switches the main switch Swli to the secondary position pl2 to connect said main node 10 to the wired subnetwork Nwb At the same time, the main control unit ECU1 switches the main switch Swl2 to the primary position pli to disconnect said node main 10 to the wired subnet Nw2 and to connect the wired subnet Nwi to the main resistor Rli.

[0162] In an illustrated step E1 F1(ECU2, 10, msg3(Id)), the secondary electronic control unit ECU2 of the secondary node 114 sends a presence message msg3 comprising the unique identifier Id of said secondary node 114.

[0163] In a step E2 illustrated F2(ECU1, 11, msg3(Id)), the main electronic control unit ECU1 of the main node 10 receives said presence message msg3 and in a step E3 illustrated F3(ECU1, Mem, Id), stores said unique identifier Id of said secondary node 114 in its memory Mem. In a non-limiting embodiment, the main control unit ECU1 waits for said presence message msg3 for a waiting time equal to 250ms in a non-limiting example.

[0164] In a step E4 illustrated F4(ECU1, 11, msgl(Id')), the main electronic control unit ECU1 of the main node 10 sends to said secondary node 114 an activation message msgl so that it switches its secondary switch Sw2, except when it is the last node of said wired subnetwork Nwb which is not the case for the secondary node 114. The activation message msgl is addressed only to said secondary node 114 thanks to the derived identifier Id' of said unique identifier Id. It will be noted that for the last secondary node 114 of the subnetwork Nwi, no activation message msgl is sent to it.

[0165] In a step E5 illustrated F5(ECU2, 10, msgl(Id')), the secondary electronic control unit ECU2 of the secondary node 114 receives this activation message msgl.

[0166] In a step E6 illustrated F6(ECU2, Sw2, p22), the secondary electronic control unit ECU2 of the secondary node 114 switches its secondary switch Sw2 to the secondary position p22 in which said secondary node 114 is connected to the next secondary node 113 unless there is no next secondary node 11 (in which case there is no connection to a next secondary node 11) which is not the case for the secondary node 114. This switching causes the wired subnetwork Nwi to be disconnected from the secondary resistor R2 associated with said secondary node 114 and is connected to the secondary resistor R2 associated with said next secondary node 113. The main node 10 can then communicate with this next secondary node 113 to retrieve its unique identifier Id.

[0167] Steps E1 to E6 are thus repeated with the secondary node 1 l3 up to the penultimate secondary node ll2 of the wired subnetwork Nwb. The main electronic control unit ECU1 knows that there are four secondary nodes 11 for the wired subnetwork Nwi. Thus, if there are p secondary nodes 11, there are p-2 repetitions of steps E4 to E6. Steps E1 to E3 are repeated for the last secondary node lli. Thus, if there are p secondary nodes 11, there are p-1 repetitions of steps E1 to E3. Steps E4 to E6 are not executed for the last secondary node 1 lb. The secondary switch Sw2 of the last secondary node 1 ^will always remain in the primary position p21.

[0168] After having retrieved the unique identifiers Id of all the secondary nodes 11 of the wired subnetwork Nwb, the main node 10 connects to the other subnetwork Nw2.

[0169] Thus, in a step E7 illustrated F7(ECU1, Swl2, pl2, Swli, pli), the main electronic control unit ECU1 of the main node 10 switches the main switch Swl2 to the secondary position pl2 to connect said main node 10 to the wired subnetwork Nw2. At the same time, the main control unit ECU1 switches the main switch Swli to the primary position pli to disconnect said main node 10 from the wired subnetwork Nwi and to connect the wired subnetwork Nw2 to the main resistance Rl2.

[0170] In a step E8 illustrated F8(ECU2, 10, msg3(Id)), the secondary electronic control unit ECU2 of the secondary node 115 sends a presence message msg3 comprising the unique identifier Id of said secondary node 115.

[0171] In a step E9 illustrated F9(ECU1, 11, msg3(Id)), the main electronic control unit ECU1 of the main node 10 receives said presence message msg3 and in a step E10 illustrated F10(ECU1, Mem, Id), stores said unique identifier Id of said secondary node 115 in its memory Mem.

[0172] In a step El 1 illustrated Fl 1(ECU1, 11, msgl(Id')), the main electronic control unit ECU1 of the main node 10 sends to said secondary node 115 an activation message msgl so that it switches its secondary switch Sw2, except when it is the last node of said wired subnetwork Nw2, which is not the case for the secondary node 115. The activation message msgl is addressed only to said secondary node 115 thanks to the derived identifier Id' of said unique identifier Id. It will be noted that for the last secondary node 117 of the subnetwork Nw2, no activation message msgl is sent to it.

[0173] In a step E12 illustrated F12(ECU2, 10, msgl(Id')), the secondary electronic control unit ECU2 of the secondary node 115 receives this activation message msgl.

[0174] In a step E13 illustrated F13(ECU2, Sw2, p22), the secondary electronic control unit ECU2 of the secondary node 114 switches its secondary switch Sw2 to the secondary position p22 in which said secondary node 115 is connected to the next secondary node 116 unless there is no next secondary node 11 (in which case there is no connection to a next secondary node 11) which is not the case for the secondary node 115. This switching causes that the wired subnetwork Nw2 is disconnected from the secondary resistance R2 associated with said secondary node 115 and is connected to the secondary resistance R2 associated with said next secondary node 116. The main node 10 can then communicate with this next secondary node 116 to retrieve its unique identifier Id.

[0175] Steps E8 to E13 are thus repeated with the secondary node 116 which is the penultimate secondary node 111 of the wired subnetwork Nw2. The electronic control unit ECU1 knows that there are three secondary nodes 11 for the wired subnetwork Nw2. Thus, if there are k secondary nodes 11, there are k-2 repetitions of steps E1 to E6. Steps E8 to E10 are repeated for the last secondary node 117. Thus, if there are k secondary nodes 11, there are k-1 repetitions of steps E8 to E10. Steps E11 to E13 are not executed for the last secondary node 117. The secondary switch Sw2 of the last secondary node 117 will always remain in the primary position p21.

[0176] When it has recovered all the unique identifiers Id of each secondary node 11 of each wired subnetwork Nwb Nw2, in a step E14 illustrated F14(ECU1, Id, Posl(ll)), the main electronic control unit ECU1 of the main node 10 associates with them the corresponding positions Posl of secondary nodes IL. It will be noted that this step can be executed at the end of each loop for each subnetwork Nwi, Nw2, or as soon as an identifier Id has been recovered instead of waiting until all have been recovered, and this at each loop for each subnetwork Nwb Nw2.

[0177] The learning phase phO is completed. The location device 10 can then operate in its operating phase phi. Thus, in a step E15 illustrated F15(ECU1, phi), the main electronic control unit ECU1 of the main node 10 activates the operating phase phi.

[0178] It will be noted that in the case where there is only one wired subnetwork Nw, but two main switches Swl, Sw2, only steps E1 to E6, and E14, E15 are carried out.

[0179] The location method 6 is now described according to a first non-limiting embodiment illustrated in [Fig.22] and according to a second non-limiting embodiment in [Fig.23].

[0180] In the same way as for the first location method 5, either the presence message msg3 is a broadcast message, namely addressed to any node on the subnetwork Nw, or it is a dedicated message addressed directly to the main node 10, which consequently includes the unique identifier of said main node 10. Thus, either the secondary nodes 11 do not know the unique identifier of said main node 10, or they do know it.

[0181] According to the first non-limiting embodiment illustrated in [Fig.22], there is only one sub-network Nw. In a non-limiting example, this single sub-network Nw comprises seven secondary nodes 1 li to 117, with secondary node 111 being closest to primary node 10.

[0182] Thus, as illustrated in [Fig.22], in the case where there is only one wired sub-network Nw, during the learning phase phO, the following steps are carried out.

[0183] In an illustrated step El F1(ECU1, 11, msg2), the main electronic control unit ECU1 of the main node 10 sends an inventory broadcast message msg2 to said secondary nodes 11 of said wired subnetwork Nw.

[0184] Upon receipt of the inventory broadcast message msg2, in a step E2 illustrated F2(ECU2, 10, msg3(Id)), the secondary electronic control unit ECU2 of the secondary node 1 returns a presence message msg3 comprising the unique identifier Id of said secondary node 1 lb. This presence message msg3 is sent following receipt of an inventory broadcast message msg2 by the secondary node 111. It is not sent automatically by the secondary nodes 11. By default, the secondary nodes 111 to 117 have their secondary switch Sw2 in the primary position p21. The inventory broadcast message msg2 from primary node 10 does not travel up to secondary nodes 112 to 117. Only secondary node 111 receives the inventory broadcast message msg2 because it is connected directly to primary node 10 on subnet Nw. The other secondary nodes 112 to 117 will receive this inventory broadcast message msg2 when they are connected to primary node 10.

[0185] In a step E3 illustrated F3(ECU1, 11, msg3(Id)), the main electronic control unit ECU1 of the main node 10 receives said presence message msg3 and in a step E4 illustrated F4(ECU1, Mem, Id), stores said unique identifier Id of said secondary node 11i in its memory Mem. In a non-limiting embodiment, the main control unit ECU1 waits for said presence message msg3 for a waiting time equal to 250ms in a non-limiting example.

[0186] In a step E5 illustrated F5(ECU1, 11, msgl(Id')), the main electronic control unit ECU1 of the main node 10 sends to said secondary node 111 an activation message msgl so that it switches its secondary switch Sw2. The activation message msgl is addressed only to said secondary node IC using the derived identifier Id' of said unique identifier Id. It will be noted that even for the last secondary node 117 of the subnetwork Nw2, an activation message msgl is sent to it.

[0187] In a step E6 illustrated F6(ECU2, 10, msgl(Id')), the secondary electronic control unit ECU2 of the secondary node 111 receives this activation message msgl.

[0188] In a step E7 illustrated F7(ECU2, Sw2, p22), the secondary electronic control unit ECU2 of the secondary node 11 switches its secondary switch Sw2 in the secondary position p22 in which said secondary node 111 is connected to the next secondary node 112. This switching causes the wired subnetwork Nw to be disconnected from the secondary resistance R2 associated with said secondary node 111 and is connected to the secondary resistance R2 associated with said next secondary node 112. The main node 10 can then communicate with this next secondary node 112 to retrieve its unique identifier Id.

[0189] Steps E1 to E7 are repeated with the secondary node 11 up to the last secondary node 117 of the wired subnetwork Nw. Thus, if there are q secondary nodes 11, there are q-1 repetitions of steps E1 to E7. As the main node 10 does not know the number of secondary nodes 11 present on the vehicle network, it repeats step EL one last time. If it does not receive any presence message msg3 (after the waiting time of 250ms for example), this means that there are no more other secondary nodes 11. Consequently, the main electronic control unit ECU1 of the main node 10 re-switches the secondary switch Sw2 of the last secondary node 1 l7 so that it returns to its primary position p21 (step not illustrated) to rebalance the wired sub-network Nw. By re-switching its switch to position p21, the last secondary node 1 l7 makes its secondary resistor R2 reappear at the end of the line of the wired sub-network Nw in order to rebalance it.

[0190] When it has retrieved all the unique identifiers Id of each secondary node 11, in a step E8 illustrated F8(ECU1, Id, Posl(ll)), the main electronic control unit ECU1 of the main node 10 associates with them the corresponding positions Posl of secondary nodes 11 thanks to a stored configuration cg of positions Posl which corresponds to the number Nb of secondary nodes 11 found. It will be noted that this step is executed after having retrieved all the unique identifiers Id and after having associated the number Nb of secondary nodes 11 with a given configuration cg of positions Posl. It is indeed necessary to know how many secondary nodes 11 there are on the vehicle network to find the correct configuration cg.

[0191] The learning phase phO is completed. The location device 10 can then operate in its operating phase phi. Thus, in a step E9 illustrated F9(ECU1, phi), the main electronic control unit ECU1 of the main node 10 activates the operating phase phi.

[0192] According to the second non-limiting embodiment illustrated in [Fig.23], there are two sub-networks Nwb Nw2 In a non-limiting example, the sub-networks Nwb Nw2 each comprise respectively the nodes 111 to 114 and the nodes 115 to 117. The secondary node 114 and the secondary node 115 are the closest to the main node 10. They are each arranged on either side of the main node 10.

[0193] Initially the main switches Swli, Swl2 of the main node 10 are positioned in the primary position p11: the main node 10 is not connected to any wired subnetwork Nwb Nw2. Furthermore, initially, the secondary switches Sw2 are switched to their primary position p21. They are connected to the corresponding secondary resistor R2.

[0194] According to this second non-limiting embodiment, the main node 10 connects first to the subnetwork Nwb. It will be noted that the choice of connecting first to the subnetwork Nwi is random. In a non-limiting embodiment, the choice is configured in the main electronic control unit ECU1 of the main node 10.

[0195] Thus, as illustrated in [Fig.23], in the case where there are two wired sub-networks Nwi, Nw2, during the learning phase phO, the following steps are carried out.

[0196] In a step E0 illustrated F0(ECUl, Swli, pl2, Swl2, pli), the main electronic control unit ECU1 of the main node 10 switches the main switch Swli to the secondary position pl2 to connect said main node 10 to the wired subnetwork Nwb At the same time, the main control unit ECU1 switches the main switch Swl2 to the primary position pli to disconnect said main node 10 from the wired subnetwork Nw2 and to connect the wired subnetwork Nwi to the main resistance Rlb

[0197] In an illustrated step El F1(ECU1, 11, msg2), the main electronic control unit ECU1 of the main node 10 sends an inventory broadcast message msg2 to said secondary nodes 11 of said first wired subnetwork Nwp

[0198] Following the reception of this inventory broadcast message msg2, in a step E2 illustrated F2(ECU2, 10, msg3(Id)), the secondary electronic control unit ECU2 of the secondary node 114 sends a presence message msg3 comprising the unique identifier Id of said secondary node 114. This presence message msg3 is sent following the reception of an inventory broadcast message msg2 by the secondary node 114. It is not sent automatically by the secondary nodes 11. By default, the secondary nodes 111 to 114 have their secondary switch Sw2 in the primary position p21. The inventory broadcast message msg2 of the primary node 10 does not reach the secondary nodes 111 to 113.Only secondary node 114 receives the inventory broadcast message msg2 because it is connected directly to primary node 10 on subnet Nwb. The other secondary nodes 111 to 113 will receive this inventory broadcast message msg2 when they are connected to primary node 10.

[0199] In a step E3 illustrated F3(ECU1, 11, msg3(Id)), the main electronic control unit ECU1 of the main node 10 receives said presence message msg3 and in a step E4 illustrated F4(ECU1, Mem, Id), stores said unique identifier Id of said secondary node 114 in its memory Mem. In a non-limiting embodiment, the main control unit ECU1 waits for said presence message msg3 for a waiting time equal to 250ms in a non-limiting example.

[0200] In a step E5 illustrated F5(ECU1, 11, msgl(Id')), the main electronic control unit ECU1 of the main node 10 sends to said secondary node 114 an activation message msgl so that it switches its secondary switch Sw2. The activation message msgl is addressed only to said secondary node 114 thanks to the derived identifier Id' of said unique identifier Id. It will be noted that even for the last secondary node lli of the subnetwork Nwi, an activation message msgl is sent to it.

[0201] In a step E6 illustrated F6(ECU2, 10, msgl(Id')), the secondary electronic control unit ECU2 of the secondary node 114 receives this activation message msgl.

[0202] In a step E7 illustrated F7(ECU2, Sw2, p22), the secondary electronic control unit ECU2 of the secondary node 1 l4 switches its secondary switch Sw2 to the secondary position p22 in which said secondary node 114 is connected to the next secondary node 1 l3 if there is a next secondary node 11. If it is the last secondary node 11 of said at least one wired subnetwork Nwi (which is not the case for the secondary node 114), it executes, but it will not be connected to any next secondary node 11. This switching causes the wired subnetwork Nwi to be disconnected from the secondary resistor R2 associated with said secondary node 114 and is connected to the secondary resistor R2 associated with said next secondary node 113 (except for the last secondary node 1 li since there is no next secondary node 11). The main node 10 can then communicate with this following secondary node 113 to retrieve its unique identifier Id.

[0203] Steps E1 to E7 are repeated with the secondary node 1 l3 until the last secondary node lli of the wired subnetwork Nwi. Thus, if there are p secondary nodes 11, there are p-1 repetitions of steps E1 to E7. As the main node 10 does not know the number Nb of secondary nodes 11 present on the vehicle network, it repeats step E1 one last time. If it does not receive any presence message msg3 (after the waiting time of 250ms for example), this means that there are no more other secondary nodes 11. Consequently, the main electronic control unit ECU1 of the main node 10 switches the secondary switch Sw2 of the last secondary node 1 C so that it returns to its primary position p21 (step not shown) to rebalance the wired subnetwork Nwi. By switching its switch back to position p21, the last secondary node 11 makes its secondary resistance R2 reappear at the end of the line of the wired subnetwork Nwi in order to rebalance it.

[0204] After repeating steps E1 to E7 for all the secondary nodes 11 of the wired subnetwork Nwb, the main node 10 connects to the other subnetwork Nw2.

[0205] Thus, in a step E8 illustrated F8(ECU1, Swl2, pl2, Swli, pli), the main electronic control unit ECU1 of the main node 10 switches the main switch Swl2 to the secondary position pl2 to connect said main node 10 to the wired subnetwork Nw2. At the same time, the main electronic control unit ECU1 switches the main switch Swli to the primary position pli to disconnect said main node 10 from the wired subnetwork Nwi and to connect the wired subnetwork Nw2 to the main resistor Rl2.

[0206] In a step E9 illustrated F9(ECU1, 11, msg2), the main electronic control unit ECU1 of the main node 10 sends an inventory broadcast message msg2 to said secondary nodes 11 of said first wired subnetwork Nw2.

[0207] Following the reception of this inventory broadcast message msg2, in a step E10 illustrated F10(ECU2, 10, msg3(Id)), the secondary electronic control unit ECU2 of the secondary node 115 sends a presence message msg3 comprising the unique identifier Id of said secondary node 115. This presence message msg3 is sent following the reception of an inventory broadcast message msg2 by the secondary node 115. It is not sent automatically by the secondary nodes 11. By default, the secondary nodes 115 to 117 have their secondary switch Sw2 in the primary position p21. The inventory broadcast message msg2 from primary node 10 does not travel up to secondary nodes 116 and 117. Only secondary node 115 receives the inventory broadcast message msg2 because it is connected directly to primary node 10 on subnet Nw2.The other secondary nodes 116 and 117 will receive this inventory broadcast message msg2 when they are connected to the primary node 10. .

[0208] In a step El 1 illustrated Fl 1(ECU1, 11, msg3(Id)), the main electronic control unit ECU1 of the main node 10 receives said presence message msg3 and in a step E12 illustrated F12(ECU1, Mem, Id), stores said unique identifier Id of said secondary node 115 in its memory Mem. In a non-limiting embodiment, the main control unit ECU1 waits for said presence message msg3 for a waiting time equal to 250ms in a non-limiting example.

[0209] In a step E13 illustrated F13(ECU1, 11, msgl(Id')), the main electronic control unit ECU1 of the main node 10 sends to said secondary node 115 an activation message msgl so that it switches its secondary switch Sw2. The activation message msgl is addressed only to said secondary node 115 thanks to the derived identifier Id' of said unique identifier Id. It will be noted that even for the last secondary node ll7 of the subnet Nw2, an activation message msgl is sent to it.

[0210] In a step E14 illustrated F14(ECU2, 10, msgl(Id')), the secondary electronic control unit ECU2 of the secondary node 115 receives this activation message msgl.

[0211] In a step E15 illustrated F15(ECU2, Sw2, p22), the secondary electronic control unit ECU2 of the secondary node 115 switches its secondary switch Sw2 to the secondary position p22 in which said secondary node 115 is connected to the next secondary node 116 if there is a next secondary node 11. If it is the last secondary node 11 of said at least one wired subnetwork Nwi (which is not the case for the secondary node 115), it executes, but it will not be connected to any next secondary node 11. This switching causes the wired subnetwork Nw2 to be disconnected from the secondary resistance R2 associated with said secondary node 115 and is connected to the secondary resistance R2 associated with said next secondary node 116 (except for the last secondary node 117 since there is no next secondary node 11). The main node 10 can then communicate with this following secondary node 116 to retrieve its unique identifier Id.

[0212] Steps E9 to E15 are repeated with the secondary node 1 up to the last secondary node 117 of the wired subnetwork Nw2. Thus, if there are k secondary nodes 11, there are k-1 repetitions of steps E9 to E15. As the main node 10 does not know the number Nb of secondary nodes 11 present on the vehicle network, it repeats step E9 one last time. If it does not receive any presence message msg3 (after the waiting time of 250 ms for example), this means that there are no more other secondary nodes 11. Consequently, the main electronic control unit ECU1 of the main node 10 switches the secondary switch Sw2 of the last secondary node 117 so that it returns to its primary position p21 (step not shown) to rebalance the wired subnetwork Nw2. By switching its switch back to position p21, the last secondary node 1 l7 makes its secondary resistance R2 reappear at the end of the line of the wired subnetwork Nw2 in order to rebalance it.

[0213] When it has retrieved all the unique identifiers Id of each secondary node 11, in a step E16 illustrated F16(ECU1, Id, Posl(ll)), the main electronic control unit ECU1 of the main node 10 associates with them the corresponding positions Posl of secondary nodes 11 thanks to a configuration cg of memorized positions Posl which corresponds to the number of secondary nodes 11 found. It will be noted that this step is executed after having retrieved all the unique identifiers Id and after having associated the number Nb of secondary nodes 11 with a configuration cg of positions Posl given. In fact, you need to know how many secondary nodes 11 there are on the vehicle network to find the correct cg configuration.

[0214] The learning phase phO is complete. The location device 10 can then operate in its operating phase phi.

[0215] Thus, in a step E17 illustrated F17(ECU1, phi), the main electronic control unit ECU1 of the main node 10 activates the operating phase phi.

[0216] It will be noted that in the case where there is only one wired subnetwork Nw, but two main switches Swl, Sw2, only steps E1 to E7 and E16, E17 are carried out.

[0217] Of course, the description of the invention is not limited to the embodiments described above and to the field described above.

[0218] Thus, the invention described presents in particular the following advantages: - it makes it possible to identify each secondary node 11 present on the vehicle network and to associate a position Posl with it so that the main node 10 can, during the operating phase phi, know from which secondary node 11 a message is coming to it, in particular a message comprising a measurement of distance in relation to the hands-free access device 3, - it allows balancing the wired sub-network(s) Nw of the vehicle network in order to have optimal transmission of messages without degradation, the balancing being done with the internal resistance R2 of the secondary node 11 to which the main node 10 connects and with a primary resistor RI associated with a sub-network Nw to which the main node 10 connects, - it is a solution that adapts to different vehicle network topologies: it is a solution that works with any position of the main node in the vehicle network, whether it is in the center or at the end of the vehicle network, - it is a solution which allows to address only one wired subnetwork Nw at a time to recover the unique identifiers Id of the secondary nodes 11 of this wired subnetwork Nw, - it is an easy solution to implement with simple circuitry.

Claims

Claims

1. Device (1) for locating secondary nodes (11) of a vehicle (2), said locating device (1) comprising a main node (10) and secondary nodes (11) connected together via at least one wired subnetwork (Nw), characterized in that: (a) - the main node (10) is configured to be connected to said at least one wired subnetwork (Nw) and comprises: - a main electronic control unit (ECU1) configured to, during a learning phase (phO): - send to the secondary nodes (11) activation messages (msgl) to switch their secondary switch (Sw2), - send to the secondary nodes (11) inventory broadcast messages (msg2) to determine the presence of a secondary node (11) on said at least one wired subnetwork (Nw), - receive presence messages (msg3) from said secondary nodes (11), said presence messages (msg3) including a unique identifier (Id) associated with each secondary node (11),- a main resistor (RI), (b)- each secondary node (11) comprises: (i)- a secondary electronic control unit (ECU2) configured to, during said learning phase (phO): - control a secondary switch (Sw2), - receive from said main node (10) an activation message (msgl) to switch its secondary switch (Sw2), - receive from said main node (10) an inventory broadcast message (msg2) to determine its presence on said at least one wired subnetwork (Nw), - send to said main node (10) a presence message (msg3) comprising a unique identifier (Id), (ii)- said secondary switch (Sw2) configured to, during said learning phase (phO), take a primary position (p21) in which said secondary node (11) is connected to a previous node which is a secondary node (11) or said main node (10),and a secondary position (p22) in which said secondary node (11) is connected to a following secondary node (11) if there is a following secondary node (11), (iii)- a secondary resistance (R2),

2.

3.

4. in the primary position (p21) of said secondary switch (Sw2) said at least one wired sub-network (Nw) being connected to said secondary resistance (R2), and in the secondary position (p22) of said secondary switch (Sw2) said at least one wired sub-network (Nw) being disconnected from the secondary resistance (R2), according to which said at least one main resistance (RI) and said secondary resistances (R2) have the same value. Location device (1) according to claim 1, wherein the connection of said main node (10) to said at least one subnetwork (Nw) is permanent. Location device (1) according to any one of the preceding claims 1 to 2, according to which the connection of said main node (10) to said at least one subnetwork (Nw) is carried out by said main electronic control unit (ECU1) which is configured to control two main switches (Swli, Swl2) including: - a first main switch (SwlJ) for, during said learning phase (phO), taking a secondary position (pl2) in which said main node (10) is connected to said at least one wired subnetwork (Nw), and - a second main switch (Swl2) for, during said learning phase (phO), taking a primary position (pli) in which said at least one sub-network (Nw) is connected to a main resistor (RI). Locating device (1) according to claim 3, wherein said main node (10) and said secondary nodes (11) are connected together via a single wired subnetwork (Nw) and said main electronic control unit (ECU1) is configured to control: - the first main switch (SwlJ) for, during said learning phase (phO), taking a secondary position (pl2) in which said main node (10) is connected to said single wired subnetwork (Nw), and - the second main switch (Swl2) to take a primary position (pli) during said learning phase (phO) in which said single sub-network (Nw) is connected to a main resistance (RI).

5. Location device (1) according to claim 3, wherein said main node (10) and said secondary nodes (11) are connected together via at least two wired sub-networks (Nwb Nw2 ) and said main electronic control unit (ECU1) is configured to control: - the first main switch (Swli) to, during said learning phase (phO), take a secondary position (pl2) in which said main node (10) is connected to said first wired sub-network (Nwi), and a primary position (pli) in which said second wired sub-network (Nw2) is connected to a second main resistor (Rl2), - the second main switch (Swl2) to, during said learning phase (phO), take a secondary position (pl2) in which said first wired sub-network (Nwi) is connected to a first main resistor (RIO,and a primary position (fold) in which said primary node (10) is connected to said second wired subnetwork (Nw2).,

6. Location device (1) according to the preceding claim, according to which during an operating phase (Phi), said main node (10) is configured to control the two main switches (Swl, Sw2) in the primary position (pl2) to connect the main electronic control unit (ECU1) to said two corresponding wired sub-networks (Nwb Nw2).

7. A location device (1) according to any preceding claim, wherein said secondary nodes (11) are beacons.

8. A location device (1) according to any preceding claim, wherein said primary node (10) uses an identifier (Id') derived from the unique identifier (Id) of a secondary node (11) to send an activation message (msgl) to said secondary node (11).

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