METHOD AND SYSTEM FOR AUTOMATIC LOCALIZATION BY MEANS OF RADIOELECTRIC SIGNALS, CORRESPONDING PROGRAM AND PROGRAM MEDIUM

Description

[0001] The present invention relates to the field of localization of electrical signal transmitters and receivers. BACKGROUND OF THE INVENTION

[0002] This is known to be a system comprising equipment distributed in a location, each equipped with a transmitter / receiver of radio signals. The radio signals are, for example, of the UWB type, that is to say, ultra-wideband.

[0003] In these systems, it is known to implement self-localization processes comprising the following steps: to have each piece of equipment emit signals containing an equipment identifier and time information enabling the equipment receiving the signals to determine a measurement of a distance separating them from the emitting equipment, to determine a relative position of the emitting equipment from the distances measured by the equipment receiving the signals, to establish a list of the equipment with their relative position and a list of distance measurements between the equipment.

[0004] The signals are usually sent in bursts.

[0005] The distance measurement between the signal emitting equipment and the signal receiving equipment is obtained by calculation from the time of flight (the time elapsed between the moment of signal emission, determinable by the receiving equipment from the time information, and the reception of the signal by the receiving equipment) and the speed of propagation of the signal in the ambient medium.

[0006] The position is obtained through a trilateration calculation. However, it appears that the accuracy of the positions thus obtained is not always sufficient, while being improvable in most cases.

[0007] It is known from document no. US-A-2016 / 061933 that a self-location method implemented by communication equipment programmed to communicate with each other and determine distances between them from the signals thus exchanged, as in the preamble of claim 1. The same is true of documents US-B-8717952 and WO-A-2012 / 131744. SUBJECT OF THE INVENTION

[0008] The invention aims in particular to improve the accuracy of positions calculated using such methods. SUMMARY OF THE INVENTION

[0009] To this end, the invention provides a method for the self-location of electronic equipment distributed in a location, each equipped with a radio signal transmitter / receiver having at least one available operating mode that determines the transmission and reception characteristics of the radio signals, the method comprising the steps of: to have each piece of equipment emit a signal containing an equipment identifier and timing information enabling at least some of the equipment receiving the signal to determine a distance measurement separating them from the emitting equipment, to determine a relative position of the emitting equipment from the distances measured by the signal receiving equipment, to establish a list of the equipment with its relative position and a list of distance measurements between the equipment,

[0010] The process includes the steps, implemented by at least one computer program, of: List, for each piece of equipment, the available operating mode(s) of the transmitter / receiver, detect from the list at least one unmeasured distance between a first piece of equipment and a second piece of equipment whose transmitter / receiver has several available operating modes, change the operating mode of the transmitter / receiver of the second piece of equipment and attempt to measure the distance between the first piece of equipment and the second piece of equipment, if successful, recalculate the positions and update the list with the last measured distance.

[0011] It has been observed that, quite often, measurements are not available for the distances between certain pieces of equipment. However, the greater the number of distance measurements, the more precise the calculated positions. The method of the invention makes it possible to detect these distances and attempt to measure them, thereby improving the accuracy of equipment location.

[0012] Preferably, the radio interface of the equipment, or of certain pieces of equipment, can advantageously have different operating modes, for example, activatable by software control to modify the transmission and / or reception characteristics of the signal. It is thus possible to provide several transmitting and / or receiving antennas, activated via a software-controlled switching component (relay, electronic switch, various outputs of an RF front-end component, etc.). These antennas have significantly different characteristics (angular sector coverage, polarization, directivity, etc.), such that one or another of the selected antennas will be more or less suitable for transmitting the radio signal under optimal conditions across the space separating the equipment.Advantageously, using two omnidirectional antennas, each covering a different polarization, allows the link budget to be modified by about ten dB, depending on which one is selected. One of the antennas will then be used by default by the system.

[0013] It is also possible to include one or more transmit and / or receive amplifiers with selectable or adjustable total gain, controlled by software to adapt the transmitted and / or received signal level and maximize the link performance between two devices. Advantageously, with an amplification gain varying within a range of approximately ten decibels, the choice of amplifier allows for the transmission of a radio signal between two nearby devices without saturation (by selecting the amplifier with the lowest gain), or between two more distant devices or devices located behind an obstacle that interferes with radio transmission (by selecting the amplifier with the highest gain). The minimum interface gain will then be used by default by the system.It is also possible to use multiple carrier frequencies for the radio signal, selectable via software to allow the radio signal to penetrate obstacles of varying types. For example, a radio signal in the 4 GHz band will be better able to penetrate a typical home environment, while a radio signal in the 6 GHz band will be better able to penetrate larger obstacles than those usually encountered in a typical home. The carrier frequency offering the best propagation through the air will then be used by default by the system.

[0014] Finally, it is also possible to include several types of software-selectable preambles in the data transmitted by the radio signal to increase the likelihood of receiver synchronization when the received signal is weak. For example, implementing a long preamble will ensure communication at the edge of range, providing a significant gain compared to a received signal with a short preamble. Since this longer preamble increases radio interface usage time and power consumption, the standard short preamble will preferably be used by default by the system.

[0015] The invention also relates to a localization system, a computer program for implementing the above process, and a data carrier containing said program.

[0016] Other features and advantages of the invention will become apparent from the following description of a particular and non-limiting embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Reference will be made to the attached drawings, including: [ Fig. 1 ] there figure 1 is a schematic view of a self-localization system according to the invention; [ Fig. 2 ] there figure 2 is a schematic view of an initial piece of equipment for this system; [ Fig. 3 ] there figure 3 is a schematic view of a second piece of equipment in this system; [ Fig. 4 ] there figure 4 is a block diagram illustrating the update of the equipment list; [ Fig. 5 ] there figure 5 is a block diagram illustrating the addition of a distance to the list of distances; [ Fig. 6 ] there figure 6 is a block diagram illustrating the removal of a distance from the list of distances; [ Fig. 7 ] there figure 7 is a block diagram illustrating the use of the distance list; [ Fig. 8 ] there figure 8 is a block diagram illustrating the adaptation of the operating modes of the transmitters / receivers. DETAILED DESCRIPTION OF THE INVENTION

[0018] With reference to the figures, the invention is described herein in application to a system comprising five electronic devices distributed in a place L. The system herein comprises four fixed devices, referenced A, B, C, D and one mobile device, referenced M, here in the form of a label provided with an electronic circuit (this type of label is commonly called a "tag" in English) and carried by an object O (such as a handbag, a set of keys...) which is herein mobile or at least capable of being moved in the place L, but also of leaving and entering it.

[0019] The equipment is separated from each other by the distances [AB], [AC], [AD], [AM], [BC], [BD], [BM], [CD], [CM].

[0020] Each of the electronic devices A, B, C, D includes a control electronic circuit 1 connected to a transmission electronic circuit 101 of a transmitter / receiver, generally designated as 100. The transmission electronic circuit 101 is connected, via a first selector switch 110, to the inputs of two amplifiers 111.1, 111.2, with different gains (amplifier 111.1 having a lower gain than amplifier 111.2), whose outputs are connected to the same second selector switch 112, which is connected to two transmitting antennas 113.1, 113.2, having horizontal and vertical polarization, respectively. The transmission electronic circuit 101 is also connected, via a first selector switch 120, to the outputs of two amplifiers 121.1, 121.2, with different gains (amplifier 121.1 having a lower gain than amplifier 121.2), having inputs connected to a second selection switch 122 connected to two receiving antennas 123.1, 123.2, having horizontal and vertical polarization respectively. The electronic transmission circuit 101 is arranged in a manner known per se for encoding signals to be transmitted and decoding received signals, selecting the carrier frequency for transmitting the signal (several carrier frequencies are predetermined, for example, one in the 4 GHz band and one in the 6 GHz band), and selecting the length of the preamble introduced into the signal (several preamble lengths are predetermined). The electronic transmission circuit 101 is also arranged here to drive the selection switches 110, 112, 120, 122 (the selection switches are, for example, relays, electronic switches, various outputs of a radio front-end component...).having a control input connected to the electronic transmission circuit 101).

[0021] Thus, the transmitters / receivers 100 of equipment A, B, C, D are arranged to have different modes of operation (we also speak here of "capability" to designate each of these modes of operation) defining characteristics of the transmission and / or reception of signals: use of transmit antenna 113.1 or transmit antenna 113.2; use of receive antenna 123.1 or receive antenna 123.2; transmit via amplifier 111.1 or 111.2; receive via amplifier 121.1 or 121.2; selection of the signal carrier frequency prior to signal transmission; selection of the preamble length prior to signal transmission.

[0022] The electronic equipment M includes an electronic control circuit 1000 connected to an electronic transmission circuit 201 connected to a transmitting / receiving antenna 102. As before, the electronic transmission circuit 201 is arranged in a manner known in itself to encode signals to be transmitted and decode received signals, select the carrier frequency for transmitting the signal (several carrier frequencies are predetermined) and select the length of the preamble introduced into the signals (several preamble lengths are predetermined).

[0023] Thus, the transmitter / receiver 200 of the electronic equipment M is arranged to have different operating modes: selection of the signal carrier frequency prior to signal transmission; selection of the preamble length prior to signal transmission.

[0024] The system is designed to implement a self-localization process comprising the following steps: to have each piece of equipment emit bursts of signals, each containing an equipment identifier and time information enabling each piece of equipment receiving one of the signals to determine a measurement of a distance separating it from the emitting equipment, to determine a relative position of the emitting equipment from the distances measured by the signal receiving equipment, to establish a list of the equipment with their relative position and a list of distance measurements between the equipment.

[0025] To this end, the transmission circuit 101 of each fixed device A, B, C, D implements the MDEK1001 localization solution manufactured by DECAWAVE. The transmission circuit 101 comprises two main components: a UWB component, part number DW1000, from DECAWAVE, and a microprocessor from NORDIC. The microprocessor is configured to execute firmware developed by DECAWAVE to operate the UWB component and set up to perform the functions defined by the invention. The two components communicate via a serial link. The UWB component is responsible for generating, receiving, and decoding radio pulses according to the characteristics defined by the program executed by the microprocessor.The program executed by each device's microprocessor is designed to configure and utilize the UWB component to transmit and receive signal bursts. Then, using the information extracted from the received signals, it processes data to estimate the distance between that device and other devices from which it has received signals. To achieve this, the program implements an "initiator" function (or initiating agent) that allows the device to query other devices within its range and process the data exchanges to obtain the distances between itself and those devices. The "initiator" function is automatically transferred by the system to the other devices sequentially to complete the measurements. This allows for the sequential acquisition of distance measurements between the devices.

[0026] A "hub" program (also called a hub agent), which can be located in any of the fixed equipment or even in an external server or in a smartphone such as the one represented in S on the figure 1 is in charge of collecting the different distance measurements taken by each of the devices that have assumed the "initiator" function, and processing them by a trilateration process to evaluate the precise location of each device in the system.

[0027] Communication between the different devices, and between the initiating agents and the concentrator, can take different paths carried by different types of link: radio link as here via UWB signals or via a wireless network for example of the Wi-Fi type (the use of a radio link is mandatory for any mobile equipment), or a wired link such as an Ethernet type link connecting the fixed equipment together.

[0028] The equipment that will serve as the reference for the coordinate system in which the positions of the equipment will be determined is, by default, the first piece of equipment to have been energized, and therefore to perform the initiator function. This equipment will be positioned at the coordinates ( X = 0, Y = 0, Z = 0).

[0029] The microprocessors of the various devices comprising the system communicate with each other via bursts of UWB signals to exchange information, notably to share the overall system view or to synchronize reference clocks. Thus, by querying one of the system's devices, it is easy to obtain a global view of the system. The device's configuration in fixed or mobile mode is achieved by changing the value of a persistent variable in the processor's memory during its construction or initial implementation.

[0030] Preferably, the microprocessor running the hub program is also responsible for communicating with a computer program (here called the supervisor software agent) via a serial port connected through a USB link, or directly through a serial link, or even through a Bluetooth link. The supervisor agent is run by a microprocessor on a host device, which can be any type of equipment (desktop, mobile, external server, etc.). The microprocessor running the hub program is thus able to receive commands to perform specific actions and to transmit a system status report to the host device at regular intervals (every second, for example) in the form of character strings, as shown below.

[0031] For example, the microprocessor periodically transmits to the host device, via a serial link, a status report of each of the equipment comprising the localization system.

[0032] The status report is presented, for example, as a string of characters such as: {'timestamp': 1569763879.354127, 'mac': c1-24-2b-c3-56-23, 'type': 'tag', 'x': 2.0143, 'y': 3.9987} {'timestamp': 1569763879.937741, 'mac': c1-24-2b-c2-27-ef, 'type': 'anchor', 'x': 0.0, 'y': 0.0} {'timestamp': 1569763879.940737, 'mac': c1-24-2b-c2-28-ea, 'type': 'anchor', 'dist': 6.00234, 'x': 6.0, 'y': 0.0} {'timestamp': 1569763879.943739, 'mac': c1-24-2b-c2-25-63, 'type': 'anchor', 'dist': 8.74452, 'x': 8.0, 'y': 3.5}

[0033] Each line corresponds to one of the system's components, and the following fields, associated with a value, are easily identifiable: Timestamp: date the report was transmitted by the tracking system; MAC: the unique identifier of the equipment; Type: type of equipment, with "tag" for mobile equipment and "anchor" for fixed equipment; x and y: coordinates in meters of the equipment within the reference frame formed by the fixed equipment. The coordinates of the fixed equipment are defined here to the nearest 0.5 meters, while the coordinates of the mobile equipment are defined to the nearest millimeter. The accuracy may differ, or even be lower, depending on the precision made possible by the system's characteristics. Dist: distance in meters between the equipment in question and the equipment forming the origin of the reference frame. This information is not available for the mobile equipment or for the equipment forming the origin of the reference frame.

[0034] The report in question lists the following equipment: a mobile equipment M located at coordinates x = 2.0143 m ; y = 3.9987 m, the fixed equipment A forming the origin of the coordinate system and located at coordinates x = 0 m ; y = 0 m, the fixed equipment B located at coordinates x = 6.0 m, y = 0 m at a distance of 6.00234 m from the fixed equipment A, the fixed equipment C located at coordinates x = 8.0 m, y = 3.5 m at a distance of 8.75643 m from the fixed equipment A.

[0035] This information is provided via the USB connection to the host device, making it easy for the supervisor agent embedded in this device to collect and process it.

[0036] According to the invention, the process further comprises the steps of: List, for each piece of equipment, the available operating mode(s) of the transmitter / receiver of each piece of equipment; detect, from the list of distances, at least one unmeasured distance between a first piece of equipment and a second piece of equipment whose transmitter / receiver has several available operating modes; change the operating mode of the transmitter / receiver of the second piece of equipment and attempt to measure the distance between the first piece of equipment and the second piece of equipment; if successful, recalculate the positions and update the list with the last measured distance.

[0037] This procedure will be detailed below.

[0038] Thus, the program executed by the microprocessor of the host device is arranged to obtain from the system, in response to a command taking the form get_capability (mac), a list of the different operating modes (or "capabilities") of the transmitter / receiver 100 of each piece of equipment.

[0039] The command output presents, as a string, the various capabilities of the equipment, ranked from the least restrictive capability in terms of implementation (which will be the default capability) to the most restrictive capability. The goal is to utilize these capabilities from the least restrictive to the most restrictive.

[0040] For example, fixed equipment includes several antennas 113.1, 113.2, 123.1, and 123.2 used for transmission and / or reception. Since antennas 113.1, 113.2, and 123.1 and 123.2 have different characteristics, and therefore different radio propagation conditions, the initiator function software will select the appropriate antenna when it wishes to establish communication with a particular device. In this example, the device has a dual capability (H-polarity and V-polarity) selectable by the program. The H-polarity capability (horizontal polarity) is selected by default because it corresponds to the resting position of the selection switch 112, 122. These capabilities are stored in the equipment's non-volatile memory during its construction, based on the actual capabilities it possesses.For example, for the device cited as an example, the return of the command will take the form: {'eq_id': c1-24-2b-c2-28-ea, 'cap1': 'pol_H', 'cap2': 'pol_V', 'cap3': NULL}.

[0041] It is easy to recognize the two capabilities 1 and 2, corresponding respectively to the horizontal (H) and vertical (V) polarities, and a capability 3 with a NULL value to indicate that the device only has two possible radio configurations. Alternatively, a different implementation of the command and its return could have shown a field indicating the number of capabilities, and fields showing each of them.

[0042] According to the invention, the supervisory software agent is implemented to handle: knowledge of the different equipment, determination of the measurements of all distances between the equipment, and the state of the actual communications corresponding to each of the distances.

[0043] The supervisor software agent can be located within one of the system's devices using available hardware and software resources; it can also be located on an external device that communicates with at least one of the system's devices via the previously described connection. This agent can also be partially distributed across several system devices.

[0044] The supervisory software agent is configured to perform several operations.

[0045] The first operation consists of maintaining in the background in the supervisor agent a list of the different equipment making up the system.

[0046] This list can be obtained, for example, by using the report generated by the system as shown previously. It is indeed easy to identify the equipment composing the system, broken down into a series of fixed equipment, identified by the word "anchor" in the "type" field and located by their coordinates, and into one or more mobile equipment identified by the word "tag" in the "type" field and also located by their coordinates.

[0047] This list is conveniently stored as records in a primary "equipment table" of a database maintained by the supervising agent. Each entry in this primary table includes, at a minimum, the identification of the corresponding equipment, which is stored, for example, in a MAC_equipment field.

[0048] Preferably, as shown in the figure 4 The system is programmed so that the supervising agent is notified of the registration or deletion of equipment when it is registered or deleted from the location system.

[0049] Each time the system state is retrieved (2000), we start by checking if there are any new devices (2001) and, if so, we retrieve the capabilities (2002) and create the record for each added device (2003).

[0050] When adding equipment, the equipment type will be specified in an Equipment_Type field, and the operating modes (capabilities) will also be specified in additional fields, for example, in a Radio_Modes field of the equipment table containing the list of means or operating modes that can be implemented in the equipment, ranked by priority. Equipment without alternative means or operating modes can populate this field with the value NULL.

[0051] Thus, the equipment table corresponding to the previous example could take at least the following form: c1-24-2b-c3-56-23, tag, NULL c1-24-2b-c2-27-ef, anchor, pol_H, pol_V c1-24-2b-c2-28-ea, anchor, pol_H, pol_V c1-24-2b-c2-25-63, anchor, pol_H, pol_V

[0052] We also check if there are any deleted equipment items (2005) and these are removed from the table if so (2006).

[0053] A second operation consists of maintaining, in the background of the supervisor agent, a list of all the distances existing between the equipment.

[0054] Indeed, a potential communication link exists between each pair of devices. This potential link is also called a "segment." The system, by its native operation, determines the length of the segments (also called distance) to deduce the relative position of one of the devices through a trilateration calculation. Therefore, for optimal system performance, it is essential that the system be able to measure as many segment lengths (or distances) as possible.

[0055] This list of potential segments corresponds to all the paired combinations of equipment obtained during the first operation. Therefore, we have ( n ( n - 1)) / 2 potential segments for nequipment. This list can be stored in a "segment table" of the database. Each entry in the segment table includes the segment identification, for example in the form of a double field ID_equipement1, ID_equipement2 containing the identifications of the equipment located at the ends of the segment as entered in the equipment table.

[0056] As represented in figures 5 And 6 , this list of segments will be enriched with records of potential new segments as new equipment appears in the equipment table, and the records corresponding to segments made obsolete will be deleted from the database when the equipment is deleted from the equipment table.

[0057] Thus, when a new piece of equipment is created in the equipment list, the program systematically scans the equipment list ( figure 5 ) For : select one of the equipment (step 2010), check if the selected equipment is the new equipment (step 2011), if not, create in the list of segments (step 2012) a new segment with the selected equipment and the new equipment as its endpoint and proceed to the next step or, if so, proceed directly to the next step, check if there is still an equipment that has not been selected (step 2013), if not, interrupt the process of adding the segment (step 2014) and, if so, select the said equipment that has not been selected (step 2015) and return to step 2011.

[0058] Thus, when a piece of equipment is removed from the equipment list, the program systematically scans the list of segments ( figure 6 ) For : select one of the segments (step 2020), check if the deleted equipment belongs to the selected segment (step 2021), if so, delete the selected segment from the list of segments (step 2022) and proceed to the next step or, if not, proceed directly to the next step, check if there is still a segment that has not been selected (step 2023), if not, interrupt the segment addition process (step 2024) and, if so, select said segment that has not been selected (step 2025) and return to step 2021.

[0059] The list of segments is used by the supervising agent as will be explained.

[0060] The location system periodically and autonomously triggers, on each of the equipment via the initiator function, distance measurements for each of the different segments, then uses these measurements via its concentrator functionality to estimate the relative location of the different equipment.

[0061] Therefore, by querying the concentrator's functionality, it is possible to know at any time the length of the different segments actually measured by the localization system. This information can be obtained in response to a get_segments command, the response of which, in the form of a string, takes, for example, the form: {'timestamp': 1569763879.937741, 'eq1_id': c1-24-2b-c2-27-ef, 'eq2_id': c1-24-2b-c2-28-ea, 'dist': 6.00234} {'timestamp': 1569763879.937869, 'eq1_id': c1-24-2b-c2-28-ea, 'eq2_id': c1-24-2b-c2-25-63, 'dist': 4.05231} {'timestamp': 1569763879.937992, 'eq1_id': c1-24-2b-c2-27-ef, 'eq2_id': c1-24-2b-c3-56-23, 'dist': 4.47739} {'timestamp': 1569763879.938069, 'eq1_id': c1-24-2b-c2-28-ea, 'eq2_id': c1-24-2b-c3-56-23, 'dist': 5.64748} {'timestamp': 1569763879.938612, 'eq1_id': c1-24-2b-c2-25-63, 'eq2_id': c1-24-2b-c3-56-23, 'dist': 6.00748}

[0062] In this string of characters, it is easy to recognize length information (i.e., distance measurements), and therefore to observe the actual existence of some of the potential segments.

[0063] This length information, or lack thereof, can be used by the supervisor agent to update the records in the segment table.

[0064] Thus, a record in the segment table could advantageously contain the following fields: Equipment ID1 and Equipment ID2 are used for segment identification. It can be advantageous to classify the two identifiers to always prioritize a fixed piece of equipment, and in the case of two pieces of equipment of the same type, prioritize the one with the lower MAC address. This avoids confusion in segment naming; Current_length represents the result of the current measurement, or NULL if measurement is impossible; Last_valid_measurement_time represents the timestamp of the last valid measurement, or NULL if no measurement is available since power-up; Valid_length represents the actual segment length used for trilateration, or NULL if no valid length is available.

[0065] Each record in the segment table will be advantageously enriched with the radio operating method or mode (capability) to be implemented in each of the end devices during subsequent communications. This information can be stored, for example, in two fields, Eq1_mode_courant and Eq2_mode_courant, containing the element from the list of operating modes contained in the corresponding record of the equipment table to be implemented during the next radio communication between the end devices.

[0066] Advantageously, when creating a potential segment in the segment list, the highest priority modes of each of the end devices will be copied into the corresponding fields of the segment table.

[0067] The segment table, populated with the information from the previous example, would then show, for example: c1-24-2b-c2-27-ef, c1-24-2b-c2-28-ea pol_H, pol_H 6.00234 1569763879.937741 6.00234 c1-24-2b-c2-25-63, 6c1-24-2b-c2-27-ef pol_H, pol_H NULL NULL 8.74452 c1-24-2b-c2-25-63, c1-24-2b-c2-28-ea pol_H, pol_H 4.05231 1569763879.937869 4.05231 c1-24-2b-c2-27-ef, c1-24-2b-c3-56-23 pol_H, NULL 4.47739 1569763879.937992 4.47739 c1-24-2b-c2-28-ea, c1-24-2b-c3-56-23 pol_H, NULL 5.64748 1569763879.938069 5.64748 c1-24-2b-c2-25-63, c1-24-2b-c3-56-23 pol_H, NULL 6.00748 1569763879.938612 6.00748

[0068] The supervising agent periodically performs a quick analysis of the segment table which may highlight a number of segments whose length could never be estimated, and a number of segments whose length can no longer be estimated, for example, a segment whose length has not been evaluated for more than ten seconds.

[0069] This lack of estimation stems from the impossibility of establishing reliable communication between the devices. The communication technology used by the devices limits the maximum range to a specified value, for example, approximately 20 meters. Therefore, if the two devices are separated by a distance greater than this limit, any communication will be technically impossible. In this case, the potential segment has no chance of existing in reality. It should therefore be identified as such in the list of segments. The verification and updating of the list of unestimated segments will advantageously be carried out cyclically by the supervising agent, for example, every minute (see the figure 7 ).

[0070] The supervising agent selects a segment from the list of segments (step 2030) and retrieves the coordinates of the corresponding equipment (step 2031).

[0071] The supervising agent calculates (step 2032) the distance between the two pieces of equipment (i.e., the segment length) using the standard formula for calculating the distance between two points. A ( x A ,y A ) And B ( x B, y B ) : AB = x B − x A 2 + y B − y A 2

[0072] The supervising agent then checks if the calculated distance exceeds a threshold value (step 2033). The threshold value corresponds to the theoretical maximum range of the location system (e.g., 20 m), i.e., the maximum range of the equipment's transmitters / receivers. An alternative is available: a. If the calculated distance between the two devices at the ends of the segment exceeds the threshold value, the supervising agent checks if one of the devices in the segment is mobile (step 2034): the corresponding record in the list will be enriched with a field indicating the potential segment's uselessness (for example, a `Realistic_Segment` field), which will take the false value "false" in this case (step 2035). The record is not deleted because, as the mobile device moves, it may return to the system's maximum theoretical range. The record corresponding to the segment will be deleted from the segment table (step 2036). This approach is chosen if both devices in the segment are fixed. Indeed, the movement of one of the devices may require it to be powered down, resulting in the device "disappearing" from the system.This disappearance triggers actions such as updating the equipment list and the segment list. The disappearance is followed by the equipment "reappearing" upon power-up. This reappearance will be handled accordingly, with the equipment list being updated and potential segments being created within the segment list. b. If the calculated distance between the two devices at the ends of the segment is less than the threshold value, the field indicating the potential segment's uselessness (Realistic_Segment field) takes a true value in this case (step 2037). However, if the radio signal propagation conditions do not allow for a satisfactory connection to be established for measurement, it is likely that modifying the capabilities of one of the end devices could improve the situation, as will be discussed later.This situation can occur as soon as the system is put into service, or it can appear later, when an element is moved, in particular a mobile device moving away from one of the fixed pieces of equipment.

[0073] The supervising agent: then checks if there is still a segment that has not been selected (step 2038), if not, interrupts the segment verification process (step 2039) and, if so, selects said segment that has not been selected (step 2040) and returns to step 2031.

[0074] This results in a number of potentially exploitable segments for which action will need to be taken.

[0075] In the example, an action will need to be taken to try to solve the segment [AC] (c1-24-2b-c2-25-63, 6c1-24-2b-c2-27-ef).

[0076] Thus, the supervising agent performs a third operation, which consists of processing potentially usable segments in an attempt to obtain a measurement (see the figure 8 ).

[0077] To do this, the supervising agent retrieves: the configuration of the equipment of the segment to be measured (step 2050) from the equipment table as well as the conditions implemented during the last measurement attempt (the operating mode used) and which are available in the corresponding record of the segment table, the capabilities of each of the equipment located at the ends of the segment to be measured (steps 2051, 2052).

[0078] The supervising agent will then: check that there is an operating mode for the first piece of equipment in the segment which has a lower priority than the operating mode used during the last attempt (step 2053), if so, command the selection of this operating mode (step 2054), if not, leave the operating mode of the first piece of equipment unchanged (step 2055) and: check that there is an operating mode for the second piece of equipment in the segment which has a lower priority than the operating mode used during the last attempt (step 2056), if so, command the selection of this operating mode (step 2057), if not, command the selection of the operating mode of the next higher priority (step 2058), perform a distance measurement operation (step 2059), record the result of the distance measurement operation (step 2060).

[0079] According to the previous example, to resolve the segment [AC] it is possible to act on the transmitter / receiver of equipment A, or on the transmitter / receiver of equipment B, or on both.

[0080] Equipment A and B each have two capabilities pol_H and pol_V, and the default configuration points to the pol_H function for each, the supervisor agent will select the pol_V function for equipment A and keep the pol_H function for equipment B.

[0081] Then, the supervisor agent will act on the initiating agent of equipment A to force it to use the selected function during the next query of the equipment located at the other end of the segment.

[0082] The command used is a set_config command (Equipment_ID1, radio_mode, Equipment_ID2) which is sent to the initiating agent of equipment C. This command is formulated, for example, as follows: ID_Equipement1 represents for example the MAC address of the selected initiating equipment (c1-24-2b-c2-25-63 for equipment C), mode_radio represents the operating mode of the initiator's radio interface (pol_V for the vertically polarized antenna), ID_Equipement2 represents for example the MAC address of the equipment located at the other end of the segment (6c1-24-2b-c2-27-ef for equipment A).

[0083] Upon receiving the command, the initiating agent of equipment A will apply the new operating mode by positioning the control signal of the selection switch 122 to activate the vertically polarized antenna for the entire duration during which it will attempt to specifically interrogate equipment C.

[0084] During its next interaction with the segment table (as shown in relation to the second operation), specifically when retrieving the latest segment measurements, the supervisor agent will update the corresponding record in the segment table, changing the Eq1_current_mode and Eq2_current_mode fields to the newly selected modes and updating the actual measurement result. If the newly selected configuration resulted in a measurement, then this configuration will automatically be reused by the initiating agent during its subsequent attempts to communicate with the equipment at the other end of the segment, as the segment will be considered resolved and the configuration will not be re-evaluated.

[0085] If the newly selected configuration did not resolve the segment measurement, then the segment will be processed again by the third operation using another combination of configurations.

[0086] The plan also includes optimizing the segment table. When a new piece of equipment appears in the system, its location will not necessarily be known. In fact, a piece of equipment will only be known once at least one segment has been defined.

[0087] The distance separating it from the initiating equipment that discovered it will be measured. Its position will therefore be located at any point on the circle whose center occupies the position of the initiating equipment and whose radius corresponds to the measurement.

[0088] If it is a fixed piece of equipment, its maximum theoretical range being known, it will not be able to communicate with equipment located outside this maximum range.

[0089] Consequently, equipment located outside a zone centered on the initiating equipment and whose radius corresponds to the maximum distance plus the maximum theoretical range will under no circumstances be able to communicate with the new equipment. The corresponding segments do not need to be created.

[0090] For example, equipment B was detected by equipment A as being at a distance d(AB), therefore at one of the points of the circle of radius d(AB) centered on equipment A. Not knowing the exact position of B but knowing its theoretical maximum range P(B), all equipment located within the circle of radius R = d(AB) + P(B) will be able to communicate with equipment B. All those located outside this circle will not be able to, and the corresponding segments will not be created.

[0091] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0092] In particular, the system may have a different structure than the one described.

[0093] The number of pieces of equipment may vary, as may their structure.

[0094] Antennas can have different polarizations and / or different directivities and / or different angular sectors.

[0095] Not all equipment has the same capabilities. Other capabilities than those mentioned are possible.

[0096] Fixed equipment can be dedicated to self-location or can have other functions such as a router function, an internet gateway function, a multimedia decoder function...

[0097] The invention has been described shows a two-dimensional positioning; it is also possible to force the system into 3D mode when at least four fixed devices are deployed in a space and not in a plane.

[0098] At least two of the devices can be connected to each other by a wired electrical link and the distance between them can be measured by means of signals transmitted over the wired electrical link.

[0099] The procedure can also be modified from what has been described. For example, optimizing the segment list is optional. The segment list and the equipment list can be combined into a single list. Note that the words "table" and "list" are used interchangeably in this description. The same applies to the words "segment" and "distance."

[0100] The computer program implementing the process can be executed on one of the system's fixed equipment, on a dedicated device, or be divided into sub-programs whose execution is distributed or not across several pieces of equipment and / or dedicated devices.

[0101] The 201 transmission circuit can include two main components: a UWB component, bearing the reference DW1000, from the company DECAWAVE and a microprocessor from the company NORDIC.

[0102] Any location solution other than that of the company DECAWAVE can be used as long as it is compatible with the operation described.

Claims

1. Auto-location method for electronic equipment items distributed in a location and each provided with a transmitter / receiver of radioelectric signals having at least one available operating method determining transmission and reception characteristics of the radioelectric signals, the method comprising the steps of: making each equipment item transmit a signal containing an identifier of the equipment item and time information allowing at least some of the equipment items receiving the signal to determine a measurement of a distance separating them from the transmitter equipment, determining a relative position of the transmitter equipment using distances measured by the equipment item receiving the signal, establishing a list of equipment items with their relative position and a list of measurements of distances between the equipment items, characterised in that the method comprises the steps, implemented by at least one computer program, of: indexing in the list, for each equipment item, the available operating mode(s) of the transmitter / receiver, detecting, using the list, at least one non-measured distance between a first equipment item and a second equipment item, the transmitter / receiver of which has a plurality of available operating modes, changing the operating mode of the transmitter / receiver of the second equipment item and attempting to measure the distance between the first equipment item and the second equipment item, in case of success, recalculating the positions and updating the list with the last distance measured.

2. Method according to claim 1, comprising the steps of recording a new equipment item and of transmitting at least one signal to measure the distance separating the new equipment item from at least one first from the equipment items.

3. Method according to claim 2, wherein, knowing a theoretical maximum range of the transmitter / receiver of the new equipment item and having the measurement of distance between the new equipment item and the first equipment item, no attempt is made to measure distance between the new equipment item and equipment items which would be away from the first equipment item by a distance greater than the sum of the theoretical maximum range of the transmitter / receiver of the new equipment item and the measurement of distance between the new equipment item and the first equipment item.

4. Method according to any one of the preceding claims, wherein the operating modes relate to: a plurality of antennas connected to a selection switch.

5. Method according to claim 4, wherein the antennas have different polarisations and / or different coverage sectors and / or different directivities.

6. Method according to any one of the preceding claims, wherein the operating modes relate to: a plurality of transmission amplifiers connected to a selection switch, and / or a plurality of reception amplifiers connected to a selection switch.

7. Method according to claim 6, wherein the amplifiers have different gains.

8. Method according to claim 7, wherein the gains are comprised within an about 10dB range.

9. Method according to any one of the preceding claims, wherein the operating modes relate to different carrier frequencies of the transmitted signal.

10. Method according to any one of the preceding claims, wherein the operating modes relate to signal preambles having different lengths.

11. Method according to any one of the preceding claims, wherein at least two of the equipment items are connected to one another by a wired electric connection and the distance between them is measured by means of signals transmitted over the wired electric connection.

12. Auto-location system comprising a plurality of electronic equipment items distributed in a location and each provided with a transmitter / receiver of radioelectric signals having at least one available operating mode determining transmission and reception characteristics of the radioelectric signals, characterised in that the system is arranged to implement the method according to any one of the preceding claims.

13. Computer program for execution on an auto-location system according to claim 12, said program comprising instructions which, when executed by said system, cause it to implement the method according to any one of claims 1 to 11.

14. Data medium containing a computer program according to claim 13, comprising instructions arranged to implement the method according to any one of claims 1 to 11.