FR3041795B1 - METHOD OF ACQUIRING AND STORING MEASUREMENT DATA USED BY AN RFID-TYPE SENSOR, COLLECTION METHOD AND ARCHITECTURE THEREOF - Google Patents

Abstract

This method (100) for acquiring and storing measurement data is implemented by a sensor of the RFID type, the sensor being associated with a programmable identifier comprising a static part and a dynamic part. The method (100) comprises a step of acquiring (110) at least one measurement, a step of forming (120) a measurement packet comprising the at least one measurement, and an integrating step (130). ) of the measurement packet in the dynamic part of the sensor identifier.

Description

Method for acquiring and storing measurement data implemented by an RFID type sensor, collection method and associated architecture

The present invention relates to a method of acquisition and storage of measurement data implemented by a sensor of the RFID type and more generally, a method of collecting measurement data acquired and stored according to this method.

In a manner known in the state of the art, the sensor RFID type (English "Radio Frequency Identification") includes a marker called equalemen-label (or "RFID tag" in English) and associated with an object to monitor, and measurement means of at least some physical parameters relating to this object such as ambient temperature, humidity or acceleration.

The sensor is generally in the form of a sticker label stuck on the object to be monitored or in the form of a chip integrated in the object to be monitored. The object to be monitored is for example a commodity, a product or a living organism whose monitoring through at least one measured physical parameter is necessary.

Such a sensor comprises in particular a storage module able to store the measurement data acquired by the measuring means and an antenna capable of transmitting these data to an interrogator via electromagnetic waves. The interrogator then makes it possible to collect the measurement data stored in a plurality of sensors and to transmit these data to a processing center such as a wired link.

Such a measurement data collection architecture, composed in particular of an interrogator and a plurality of sensors, makes it possible to ensure wireless links between the measurement means and the associated processing center and thus to avoid the use of cables .

This is particularly advantageous for the space domain. Indeed, the use of such a collection architecture in a spatial device such as a launcher or unsatellite makes it possible to minimize the use of cables in this device while ensuring the necessary monitoring of the components of this device.

Thus, for example, in the case of a launcher, sensors of the RFID type are associated with different components of this launcher and make it possible to measure physical parameters of these components, such as, for example, the temperature during the different operating phases of the launcher. The measurement data are stored in the corresponding sensors and are then transmitted to an interrogator which in turn transmits them to a processing center. Other features of the interrogator are also possible. Thus, for example, certain types of interrogator make it possible to remotely configure the associated sensors, for example to program the measurement rate or else to regulate the access rights to the data stored in the corresponding storage modules.

In general, three types of sensor are distinguished.

The so-called active sensors have their own internal power source for powering all the internal components and in particular the antenna and the measuring means of these sensors.

The sensors, said passive, are devoid of internal power source and are powered by the electromagnetic field emitted by the interrogator during communication with these sensors.

The so-called semi-passive sensors have an internal power source that can supply at least some internal components, such as measuring means. The other components, such as the antenna, are powered by the electromagnetic field emitted by the interrogator.

The communication between the interrogator and the sensors is standardized according to, for example, the ISO 18000-6C standard also known as the "EPC Gen2".

Thus, a sensor made according to this standard comprises a storage moduleivelated in several blocks, namely the blocks "Reserved", "TID >>," EPC "and" User ".

The "Reserved" block is used to store the passwords used to lock access to all the data stored in the storage module by an unauthorized interrogator.

The block "TID" contains a unique identifier specific to each component sensor. This identifier is factory programmed and non-modifiable.

The "EPC" block contains a programmable identifier of the sensor whose maximum size is for example 496 bits.

The "User" block is an optional user memory whose size reaches, for example, 8 KB. Generally, the measurement data acquired by the sensor are stored in this block.

Any attempt by an interrogator to access the measurement data contained in particular in the "User" block must be preceded by an identification of the inquestion sensor. This identification is characterized in particular by the transmission, from the sensor, of its identifier contained in the "EPC" block.

For this, several steps are necessary.

In particular, the interrogator first sends a Select command followed by a Query command. These two commands are used to set the transmission channel.

If a sensor is present in the radio coverage field of the interrogator and meets the requirements set by the previous commands, it responds by a random number named RN16 to the interrogator.

Then, the interrogator receives this random number and confirms the reception by an acknowledgment named Ack.

The transmission channel between the sensor and the interrogator is now established, the sensor then returns its identifier contained in the block "EPC".

When the transmission channel is established, the interrogator can access the other blocks of the sensor storage module and in particular the "User" block by sending corresponding commands to the sensor.

However, such a method of collecting measurement data is not completely satisfactory.

In particular, the rate of transmission of measurement data according to this method of collection to the interrogator, is relatively slow. This rate is then not suitable for sensors capable of acquiring a relatively large number of measurement data, for example certain sensors used in a launcher.

The present invention aims to overcome this disadvantage. To this end, the subject of the invention is a method for acquiring and storing measurement data implemented by an RFID type sensor, the sensor comprising a storage module and associated with a programmable identifier stored in the storage module, the identifier comprising a static part and a dynamic part; the method comprising a step of acquiring at least one measurement, and being characterized in that it further comprises the following steps: - forming a measurement packet comprising the at least one measurement acquired during step d acquisition; - integration of the measurement package into the dynamic part of the sensor identifier.

According to other advantageous aspects of the invention, the method for acquiring and disposing of measurement data comprises one or more of the following characteristics, taken separately or according to all the technicallypossible combinations: the acquisition step comprises: acquisition of N measurements among which a measurement is chosen as a reference measurement, the parameter N being a natural number greater than one; the training step comprises calculating N-1 deviations of N-1 measurements from the reference measurement, the measurement packet including the reference measurement and said deviations; each subsequent training step furthermore comprises calculating additional M deviations of M additional measurements with respect to the reference measurement and integrating said deviations in the measurement packet, the additional M measurements that are etablative to the measurement packet formed during a measurement. preceding formation step, the parameter M being a natural number greater than or equal to one and less than or equal to N; the training step further comprises calculating a redundant control code for the content of the measurement packet and integrating said code into the measurement packet; - the control code corresponds to the cyclic redundancy check. The subject of the invention is also an RFID type sensor comprising a storage module and being associated with a programmable identifier stored in the storage module, the identifier comprising a static part and a dynamic part; the sensor further comprising measuring means of at least one measurement, and being characterized in that it further comprises calculation means able to: - form a package of measurements comprising the at least one measurement acquired by the means of measurement; - integrate the measurement package into the dynamic part of the sensor identifier.

According to other advantageous aspects of the invention, the sensor comprises one or more of the following characteristics, taken separately or in accordance with all the technically possible combinations: the static part of the identifier of this sensor is stored in a memory module of the module storage; the dynamic part of the identifier of the sensor is stored in a live memory of the storage module; - The read-only memory of the storage module further comprises a pointer to part of the RAM of the storage module in which is stored the dynamic part of the identifier of this sensor. The invention also relates to a method for collecting measured data stored in at least one RFID type sensor according to the acquisition and storage method, the collection method being implemented by an RFID type interrogator and comprising a step of acquiring the identifier of the at least one sensor; the method being characterized in that the acquisition step of the identifiercomporte additionally extraction of the measurement packet of the acquired identifier.

According to other advantageous aspects of the invention, the collection method comprises one or more of the following characteristics, taken separately or in any technically possible combination: the method further comprises the following steps, carried out before the step acquiring the identifier: - sending a command for setting the transmission channel between the interrogator and the at least one sensor; receiving a random number generated by the at least one sensor; and - sending an acknowledgment to the at least one sensor. the method further comprises a step of extracting measurement data from the measurement package; said etan step is performed by the interrogator or by a remote processing center of the interrogator. The invention also relates to a measurement data collection architecture comprising at least one RFID type sensor and an RFID type interrogator; characterized in that: - the at least one sensor comprising a storage module and being associated with a programmable identifier stored in the storage module, the identifier comprising a static part and a dynamic part; the sensor further comprising measuring means of at least one measurement, and being characterized in that it further comprises calculation means capable of: - forming a measurement packet comprising the at least one measurement acquired by the means of measurement; integrating the measurement packet into the dynamic part of the sensor identifier; the interrogator comprising means for acquiring the identifier of the at least one sensor and means for extracting the measurement packet from the acquired identifier.

The features and advantages of the invention will become apparent on reading the description which follows, given solely by way of nonlimiting example and with reference to the accompanying drawings, in which: FIG. 1 is a schematic view of an architecture collection device according to the invention, the architecture comprising in particular a plurality of sensors; FIG. 2 is a detailed schematic view of one of the sensors of FIG. 1, the sensor comprising a storage module; FIG. 3 is a schematic view of the storage module of FIG. 2; FIG. 4 is a flowchart of a method for acquiring and storing measurement data according to the invention; FIG. 5 is a schematic view of the structure of a dynamic part of the identifier of the sensor of FIG. 2; and FIG. 6 is a flowchart of a measurement data collection method according to the invention. The measurement data collection architecture 10 of FIG. 1 comprises a interrogator 12 and a plurality of sensors 14A to 14N. The interrogator 12 and the sensors 14A to 14N are able to communicate with each other using the RFID (Radio Frequency Identification) technology known in the state of the art. The communication is thus carried out wirelessly, via electromagnetic waves.

The sensors 14A to 14N are respectively associated with objects 16A to 16N and allow monitoring these objects by taking measurements of the physical parametersrelative to these objects 16A to 16N.

Thus, according to an exemplary embodiment, each object 16A to 16N has a component of a space launcher such as a computer, a combustion chamber, a reservoir, valves, a divergent, etc.

Each physical parameter relating to these components is chosen for example from the group comprising: temperature, humidity, speed, acceleration, pressure, etc.

The sensors 14A to 14N then make it possible to take measurements of theseparameters, to generate corresponding measurement data, to store these data and to transmit them to the interrogator 12. The interrogator 12 comprises an antenna 17 defining a radio frequency coverage field of the interrogator 12 and a communication module 18.

In particular, the antenna 17 is able to communicate with the sensors 14A to 14Nse found in the field of coverage by sending or receiving electromagnetic waves and especially radio waves, to these sensors orissues of these sensors.

The communication module 18 is able to generate data to be sent to the sensors 14A to 14N and to receive data sent by these sensors 14A to 14Notamment to collect measurement data stored in these sensors.

The communication module 18 is also able to transmit the measured data collected to a processing center 19 via for example a wired link. The processing center 19 is for example a control computer for depilating the launcher based on the measurement data collected.

The communication between the sensors 14A to 14N and the interrogator 12 is, for example, in accordance with the ISO 18000-6C standard.

The sensors 14A to 14N are substantially similar. Thus, only the 14Asera sensor described in more detail later with reference to FIG.

Thus, as illustrated in this FIG. 2, the sensor 14A includes a marker 22, measurement means 24 and an internal power source 26.

The measuring means 24 are connected to the corresponding object 16A to monitor and allow to measure at least one physical parameter relating to this object 16A.

The measuring means 24 are made according to technologies known per se andpresent, for example, a mechanical and / or electrical resistance sensitive to changes in the corresponding physical parameter or parameters.

According to the exemplary embodiment illustrated in FIG. 2, the measuring means 24 are powered by the internal power supply source 26 which is, for example, in the form of a battery.

The marker 22, also known by the term "tag", is a flexible radio-tag or chip glued or fixed by any means appropriate to the object 16A to be monitored.

The marker 22 comprises an antenna 30, a storage module 32 and a microprocessor 34. The antenna 30 makes it possible to communicate with the interrogator 12 and more particularly with the antenna 17 of the interrogator 12 via electromagnetic waves.

The storage module 32 is capable of storing digital data relating to the operation of the sensor 14A and in particular measuring data corresponding to measurements taken by the measuring means 24. The structure of the storage module32 will be explained in more detail below.

The microprocessor 34 is able to control the operation of the sensor 14A. In particular, the microprocessor 34 is able to control the taking of measurements by the measuring means 24 according to a programmed schedule.

According to the exemplary embodiment illustrated, all the components of the marker 22 is powered by the internal power source 26. It is therefore an active sensor. Other exemplary embodiments of the sensor 14A are also possible. Thus, according to an exemplary embodiment, at least some components of the marker 22, for example the antenna 30, are powered only during the communication with the interrogator 12 by the energy contained in the electromagnetic waves. It is therefore a semi-passive sensor.

According to another embodiment, the set of components of the marker 22 and the measurement taking means 24 are fed only during communication with the interrogator 12 by the energy contained in the electromagnetic waves. It is therefore a passive sensor.

The structure of the storage module 32 is illustrated in more detail in FIG.

With reference to this figure, the storage module 32 comprises a memory memory 40 and a random access memory 41.

The read-only memory 40 is for example of the EEPROM type (Electrically-ErasableProgrammable Read-Only Memory in English or "electrically erasable and programmable read-only memory" in French). The data stored in this memory 40 is thus not lost when the storage module 32 is not powered.

The RAM 41, also called system memory >> is of the RAM type ("Random Access Memory" in English or "direct access memory" in French). The hard disk memory 41 makes it possible to store data only when the destocking module 32 is powered.

The RAM 41 ensures in particular the exchange of data between the different components of the sensor 14A.

In a manner known per se, the speed of writing and reading the data contained in the random access memory 41 is higher, for example at least 25, than the speed of writing and reading the data contained in the read-only memory 40.

Moreover, the writing / reading in the RAM is more advantageous from the point of view of energy consumption.

The memory (alive and dead) of the storage module 32 is distributed among different blocks. Thus, all the data contained in the storage module 32 is distributed between these blocks, which in particular makes it possible to control the access rights to these data according to their importance for the operation of the sensor 14A.

In the example illustrated in FIG. 3, the memory of the storage module 32 is distributed between four blocks which are designated by the references 45 to 48.

Block 45 corresponds to a memory reserved for the storage of overwords used to lock access to all the data stored in the storage module 32. Such a block is known by the term "Reserved" in English.

Block 46 contains a unique identifier specific to each component of sensor 14A. The data stored in this block is programmed at the factory and can not be changed. Such a block is known as the "TID".

Block 47 is able to store a programmable identifier of the sensor 14A explained in greater detail later. The size of this block is equal for example to 496 bits. Such a block is known as the "EPC".

Finally, the block 48 is able to store so-called "user" data, that is, data dependent on the function of the sensor 14A, such as the measurement data. The size of this block is equal to 8Ko for example. Such a block is known as "User" in English. This block is optional.

Blocks 45 to 48 use ROM 40 to store the corresponding data.

According to the invention, the block 47 for storing the programmable identifier of the sensor 14A furthermore makes it possible to store a pointer 50 to an extension 52 of this block in the random access memory 41.

The pointer 50 makes it possible in particular to extend the block 41 by the extension 52 in the live memory 41. The programmable identifier of the sensor 14A comprises a static part and a dynamic part.

The static part corresponds to a static identifier of the sensor 14A. This identifier is for example unique among the sensors 14A to 14N and makes it possible to distinguish the sensor 14A in a unique way and certain among these sensors by the interrogator 12.

The static part of the identifier is stored directly in the block 47, that is to say, in the read-only memory 40.

The dynamic bet of the identifier is stored in the extension 52, that is to say, in the random access memory 41.

The dynamic part of the identifier is modifiable by the microprocessor 34 according to a measurement data acquisition and storage method 100 described hereinafter with reference to FIG. 4 illustrating a flowchart of its steps.

Initially, the rate of taking measurements of at least one physicelative parameter to the object 16A is determined. The steps of the acquisition and storage method 100 described hereinafter are then iterated according to the determined rate.

During an initial step 110 of the acquisition and storage method 100, the microprocessor 34 controls the taking of a plurality of measurements, by means of measurement 24.

In particular, this step includes the acquisition of N measurements where the Nest parameter a natural number greater than 1 and equal for example to 7.

Among these acquired measures, a measure is chosen as a reference measure. For example, the first measurement taken is chosen as the reference measure.

In a next step 120, the microprocessor 34 forms a packet of measurements P in the RAM 41 which comprises in particular the reference measurement and a number of the packet.

The reference measurement is stored for example on 16 bits.

The number of the packet corresponds for example to the number of iterations of the method100 carried out previously.

During the same step 120, the microprocessor 34 calculates N-1 deviations of N-1 measurements other than the reference measurement, with respect to the reference measurement. It then integrates these deviations into the P measurement package.

When the parameter N is equal to 7, the six calculated differences are, for example, stored on 8 bits.

During the same step 120, the microprocessor 34 calculates M additional deviations of / additional measurements with respect to the reference measurement, where the parameter M is a natural number greater than or equal to 1 and less than or equal to N.

The parameter M is for example equal to 4.

The M additional measurements relate to the packet of measurements P formed during a previous training step 120. In other words, the M additional measurementscorrespond to measurements acquired in step 110 by the measuring means 24 during a previous iteration of the method 100.

The additional M deviations are integrated in the P measurements package.

When the parameter M is equal to 4, the four calculated differences are, for example, stored on 8 bits.

In the same step 120, the microprocessor 34 calculates a cyclic redundancy check code of the contents of the measurement packet P and integrates this code into the measurement package P. This code is for example calculated according to the technology known under the name CRC ("Cyclic Redundancy Check >>).

Optionally, the measurement package P is then compressed according to technologies known per se.

During a final step 130, the microprocessor 34 modifies the dynamic part of the identifier of the sensor 14A by integrating therein the measurement packet P formed in step 120.

The measurement packet P is thus stored in the extension 52 of the block 47, that is to say, in the random access memory 41.

FIG. 5 illustrates the structure of the measurement packet P formed during the acquisition and storage process 100.

Thus, with reference to this figure, the packet of measurements P has a field Nb corresponding to the number of the packet, a field MR corresponding to the measurement of reference, fields e? at e6 corresponding to the six deviations from the reference measurement, fields e. at e.4 corresponding to the four additional deviations and a CRC field corresponding to the cyclic redundancy check code.

A method 200 for collecting measurement data implemented by the collection architecture 10 will now be explained with reference to FIG. 6 illustrating a flowchart of its steps.

Initially, one of the sensors 14A to 14N, for example the sensor 14A, is in the field of coverage of the interrogator 12.

The measurement data are acquired and stored in the storage module 32 of the sensor 14A according to the acquisition and storage method 100 described above.

In particular, according to method 100, the measurement data is integrated in the measurement packet P which is in turn integrated in the dynamic part of the sensor identifier 14.

During an initial step 210 of the collection method 200, the interrogator 12 sends in its coverage field a Select command, followed by a Query command. These two commands are used to set the transmission channel.

In a next step 220, if the sensor 14A meets the requirements set by the preceding commands, it responds with a random number named RN16 to the interrogator 12.

In a next step 230, the interrogator 12 receives this random number andconfirms the reception by an acknowledgment Ack.

The transmission channel between the sensor 14A and the interrogator 12 is then established.

In a next step 240, the sensor 14A sends its programmable identifier contained in the block 47 to the interrogator 12.

During a next step 250, the interrogator 12 receives the identifier of the sensor 14Aet extracted from this identifier the static part and the dynamic part.

Then, the interrogator 12 identifies the sensor 14A uniquely between the sensors 14A through 14N using the static portion.

Then, the interrogator 12 extracts the measurement packet from the dynamic part of the identifier.

According to an alternative embodiment, the interrogator 12 determines the integrity of the packet of measurements P received by analyzing the CRC code contained in this packet.

If the CRC code is not verified, the interrogator 12 resets the transmission channel and receives again the identifier of the sensor 14A to retrieve the package again.

If the CRC code is verified, the interrogator 12 transmits the packet number, reference blade, the deviations and the additional deviations to the processing center 19.

The processing center 19 analyzes these measurements in particular according to the number of the packet, which makes it possible to restore the chronology of taking the corresponding measures.

According to another variant embodiment, the interrogator 12 directly transmits the measurement package P to the processing center 19 which analyzes in particular its integrity.

During an optional step 260, the interrogator 12 continues the communication with the sensor 14A to, for example, program this sensor 14A or extract data contained in the block 48.

The collection method 200 is similarly implemented whena plurality of sensors 14A-14N are in the interrogator's field of coverage12. In this case, the interrogator 12 communicates in parallel with these sensors.

It is conceivable that the invention has a number of advantages.

In particular, the invention makes it possible to considerably accelerate the collection of measurement data.

In fact, the measurement data are transmitted directly with the sensor identifier, which makes it possible to avoid the sending of an express command requesting these data and thus to reduce the number of exchanges between the interrogator and the sensor.

The measurement data according to the invention are stored in the sensor random access memory, which makes it possible to increase the speed of their writing or reading by the different components of the sensor.

In addition, the integrity of the received measurement packet is verified with the CRC code which increases the robustness of the collection architecture.

Finally, when the number of sensors in the field of coverage of the interrogator is very high (for example, 10 sensors), it frequently happens that the identifier is transmitted several times per session. This then contributes to the redundancy of the measurement data that can be achieved during the analysis of these data by the processing center.

Of course, other exemplary embodiments are also possible. In particular, the invention is applicable, in addition to the space domain, in many technical domains.

Claims (8)

1, -Process (100) for acquiring and storing measurement data implemented by a sensor (14A, ..., 14N) of the RFID type, the sensor (14A, ..., 14N) comprising a module (32 ) storing and being associated with a programmable identifier stored in the storage module (32), the identifier comprising a static part and a dynamic part; the method (100) comprising a step of acquiring (110) at least one measurement, and being characterized in that it further comprises the following steps: - forming (120) a packet of measurements (P) having the at least one measured value during the acquisition step (110); integration (130) of the measurement packet (P) in the dynamic part of the identifier of the sensor (14A ..... 14N); the dynamic part of the sensor identifier (14A ..... 14N) being stored in a random access memory (41) of the storage module (32). 2, - Method (100) according to claim 1, characterized in that the acquisition step (110) comprises the acquisition of Λ / measures among which a measurement ischosen as a reference measurement, the parameter N being a higher natural number has a. 3, - Method (100) according to claim 2, characterized in that the forming step (120) comprises the calculation of N-1 deviations of N-1 measurements compared to the reference measurement, the measurement packet (P) including the reference measurement and the said deviations. 4, - Method (100) according to claim 2 or 3, characterized in that each further training step (120) further comprises calculating M additional deviations of M additional measurements from the reference measurement and integrating said differences into the measurement packet (P), the M additional measurements being relative to the measurement packet (P) formed during a previous forming step (120), the parameter M being a natural number greater than or equal to one and less than or equal to N 5, - Method (100) according to any one of the preceding claims, characterized in that the forming step (120) further comprises the calculation of a control code redundant the contents of the measurement packet (P) and integrating said code into the measurement packet (P). 6, - Method (100) according to claim 5, characterized in that the control code corresponds to the cyclic redundancy check (CRC). 7, - RFID type sensor (14A 14N) comprising a storage module (32) associated with a programmable identifier stored in the storage module (32), the identifier comprising a static part and a dynamic part; the sensor (14A ..... 14N) further comprising measuring means (24) of at least one measurement, and being characterized in that it further comprises calculating means (34) able to: - form a measurement packet (P) comprising the at least one measurement acquired by the measuring means (24); integrating the measurement packet (P) into the dynamic part of the sensor identifier (14A, ..., 14N); the dynamic part of the sensor identifier (14A, ..., 14N) being stored in a random access memory (41) of the storage module (32). 8, - Sensor (14A, ..., 14N) according to claim 7, characterized in that the party of the identifier of this sensor (14A, ..., 14N) is stored in a read-only memory (40) of the storage module (32). 9, - Sensor (14A, ..., 14N) according to claim 8, characterized in that the read-only memory (40) of the storage module (32) further comprises a pointer (50) towards the part (52) of the RAM (41) of the storage module (32) in which eststockée the dynamic part of the identifier of this sensor (14A ..... 14N). 10, - Method (200) for collecting measurement data acquired and stored in at least one RFID-type sensor (14A ..... 14N) according to the acquisition and storage method (100) according to any one of Claims 1 to 6, the collection method (200) being implemented by an RFID interrogator (12) and having an acquisition step (250) of the identifier of the at least one sensor (14A,. .., 14N); the method (200) being characterized in that the acquisition step (200) of the identifier further comprises extracting the measurement packet (P) from the acquired identifier. 11, - Method (200) according to claim 10, characterized in that it further comprises the following steps, performed before the step of acquisition (250) of the identifier: - sending (210) a command for setting the transmission channel between the interrogator (12) and the at least one sensor (14A, ..., 14N); - receiving (220) a random number generated by the at least one sensor (14A ..... 14N); and sending (230) an acknowledgment to the at least one sensor (14A, ..., 14N). 12, - Method (200) according to claim 10 or 11, characterized in that it further comprises a step of extracting measurement data from the measurement packet (P); said step being implemented by the interrogator (12) or by a processing center (19) remote from the interrogator (12). 13, - Measurement data collection architecture (10) comprising at least one RFID type sensor (14A, ..., 14N) according to claim 7 and an interrogator (12) of the RFID type, the interrogator comprising means for acquiring the identifier of the at least one sensor (14A, ..., 14N) and means for extracting the measurement packet (P) from the acquired identifier.