Method for calibrating a transmitting array antenna with aesa-type phase control and associated calibration system

Abstract

The present invention relates to a method for calibrating a transmitting array antenna (11), comprising the following steps of: - selecting (110) at least one transmitting radiating element to be tested; - forming (115) a basic signal to be transmitted per transmitting radiating element to be tested by injecting a calibration signal; - introducing (120) a particular modulation into the basic signal to be transmitted per transmitting radiating element to be tested; - transmitting (130) a beam of basic signals; - receiving (140) a signal per receiving radiating element; - extracting (150), from the received signal, a transmitted basic signal corresponding to the transmitting radiating element to be tested; - comparing (155) the extracted basic signal with the transmitted basic signal; - correcting (160) calibration parameters for the transmitting radiating element to be tested.

Description

[0001] DESCRIPTION

[0002] TITLE :

[0003] Method for calibrating an AESA-type phased array transmitting antenna and associated calibration system

[0004] The present invention relates to a method for calibrating an AESA type phased array transmitting antenna.

[0005] The present invention also relates to a calibration system associated with such a method.

[0006] In particular, the technical field of the invention relates to phased array antennas (or “phased array antennas” in English) and in particular AESA (Active Electronically Scanned Array) type array antennas.

[0007] In a manner known per se, two-dimensional pointing in a direction by such an antenna is obtained by applying appropriate phase (and / or delay) and amplitude weights to the radiating elements.

[0008] These amplitudes and phases can be generated by digital commands on analog components, also called ABF (Analog Beam Forming) components. These components can include various controllable gain amplifiers, programmable phase shifters, programmable delay lines, etc.

[0009] The above-mentioned antenna type can be used in general radio communication (e.g. Satcom GEO, MEO, LEO, X, Ku, Ka bands, etc.) as well as in radars.

[0010] For this type of antenna, there is a need to guarantee the side lobe levels with respect to radiocommunication standards. For this, it is generally necessary to carry out a calibration of different elements forming the antenna following variations occurring during its life cycle.

[0011] These variations can occur in the various components of the antenna and can be caused by multiple reasons. These reasons include external conditions (temperature, humidity, etc.), power supply, vibrations, aging of materials, etc.

[0012] The state of the art already offers some methods for calibrating this type of antenna.

[0013] So, one of these methods is to perform a purely factory calibration with the expectation that this calibration will last the entire lifetime of the antenna. Another calibration method is to determine maintenance periods during which the antenna is not operational.

[0014] It is therefore clear that the methods of the state of the art are not satisfactory and in particular do not allow regular calibration of the network antenna to be carried out without interrupting its operation.

[0015] One of the objectives of the present invention is to propose a regular calibration of an AESA type array antenna throughout its life cycle and without interruption of its nominal operation. In addition, the calibration according to the invention can be implemented by the array antenna itself, that is to say autonomously.

[0016] To this end, the invention relates to a method for calibrating an AESA type phased array transmitting antenna, the transmitting array antenna comprising:

[0017] - a plurality of radiating emission elements;

[0018] - at least one receiving radiating element arranged among the transmitting radiating elements;

[0019] - an analog beamforming module capable of forming for each radiating emission element an elementary nominal signal to be emitted from a radiofrequency signal;

[0020] - a modem capable of generating the radiofrequency signal;

[0021] The process includes the following steps:

[0022] - selection of at least one radiating emission element to be tested;

[0023] - formation of an elementary signal to be emitted by the radiating emission element to be tested by injecting a calibration signal in place of or in addition to the nominal elementary signal to be emitted by this radiating emission element to be tested;

[0024] - introduction of a particular modulation into the elementary signal to be emitted by the radiating emission element to be tested;

[0025] - emission of a beam of elementary signals by all of the radiating emission elements;

[0026] - reception by a receiving radiating element of a signal formed from the beam emitted via a coupling between the transmitting radiating element to be tested and this receiving radiating element;

[0027] - extraction of the received signal from an elementary signal emitted corresponding to the radiating emission element to be tested using the particular modulation;

[0028] - comparison of the extracted elementary signal with the elementary signal emitted by the radiating emission element to be tested; - correction of calibration parameters of the radiating emission element to be tested based on said comparison.

[0029] According to other advantageous aspects of the invention, the method comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0030] - the steps of the method are repeated for each radiating emission element of the emission network antenna to be calibrated;

[0031] - the steps of the method are repeated during operation of the transmitting network antenna in nominal mode;

[0032] - the introduction of the particular modulation includes the introduction into the elementary signal to be emitted by the radiating emission element to be tested of a code in phase and / or in delay and / or in amplitude;

[0033] - when during the selection step several radiating emission elements to be tested are selected, the other steps of the method are implemented in parallel for each of the radiating emission elements to be tested selected using a modulation specific to each of the radiating emission elements to be tested;

[0034] - the calibration parameters of a radiating emission element include phase and / or delay and / or amplitude weights associated with this radiating emission element;

[0035] - the receiving radiating element operates at the same frequency as the transmitting radiating element to be tested;

[0036] - the receiving radiating element is arranged according to one of the possibilities:

[0037] - in the same pattern as the radiating emission element to be tested;

[0038] - in the same slab the radiating emission element to be tested but in a different pattern;

[0039] - in a slab other than the slab of the radiating emission element to be tested.

[0040] - the step of comparing the extracted elementary signal with the elementary signal emitted by the radiating emission element to be tested comprises a measurement of the phase and / or delay and / or amplitude difference between the calibration signal emitted and that received via coupling between the radiating emission element to be tested and the radiating reception element;

[0041] - the calibration signal is injected into a nominal signal to be transmitted by the transmission network antenna at the modem or at a pattern comprising the transmission radiating element to be tested.

[0042] The present invention also relates to a system for calibrating an AESA type phased array transmission antenna, comprising a calibration modem; a reception circuit connecting at least one radiating reception element to the calibration modem and a control unit.

[0043] The calibration system is configured to implement at least some steps of the process as defined previously.

[0044] These characteristics and advantages of the invention will appear on reading the description which follows, given solely as a non-limiting example, and made with reference to the appended drawings, in which:

[0045] - [Fig. 1] Figure 1 is a schematic view of a calibration system for a transmitting array antenna to be calibrated, according to the invention;

[0046] - [Fig. 2] Figure 2 is a schematic view of a transmitting module of the transmitting array antenna of Figure 1;

[0047] - [Fig. 3] Figure 3 is a schematic view of a pattern forming part of the emission module of Figure 2;

[0048] - [Fig. 4] Figure 4 is a schematic view of a control unit associated with a group of radiating elements of the pattern of Figure 3;

[0049] - [Fig. 5] Figure 5 is a flowchart of a calibration method implemented at least partially by the calibration system of Figure 1; and

[0050] - [Fig. 6] Figure 6 is a diagram illustrating the implementation of at least some steps of the method of Figure 5.

[0051] Figure 1 in fact illustrates a calibration system 10 of a transmission network antenna to be calibrated 11. This calibration system 10 is integrated into the antenna 11.

[0052] The transmitting array antenna to be calibrated 11 is a phased array antenna of the AESA (Active Electronically Scanned Array) type. This array antenna 11 comprises a transmitting assembly 25 adapted to transmit radio signals to another antenna.

[0053] The transmission assembly 25 comprises a transmission module 31 for transmitting a beam of elementary signals, a beam-forming module 32 for forming a beam of elementary signals from a radiofrequency signal, a modem 33 for generating the radiofrequency signal from the useful data and a control module 34 for controlling the operation of the components of the transmission assembly 25.

[0054] The control module 34 is for example of the ACU (Antenna Control Unit) type, usable to point the transmission antenna 11 in the desired direction. This module 34 is notably configured to control the operation of the beamforming module 32 and the transmission module 31. The control module 34 notably comprises a calibration table comprising calibration parameters for each radiating element explained in more detail below. These calibration parameters notably comprise phase (and / or delay) and amplitude weights to be applied to the corresponding radiating element when transmitting an elementary signal.

[0055] The modem 33 is for example known per se. It makes it possible in particular to generate a radiofrequency signal from useful data. The useful data is the data to be transmitted by the transmission antenna 11 which is generated for example by an external computing unit.

[0056] Figure 2 illustrates an example of respective arrangement of the transmission module 31 and the beamforming module 32.

[0057] In the example of this figure 2, the transmission module 31 comprises a plurality of tiles 40-1, 40-N. The tiles 40-1, ..., 40-N have different physical entities arranged for example on a support of the transmission antenna 11 separately from one another. The tiles 40-1, ..., 40-N are for example substantially identical to each other. By way of example, the number N of tiles varies for example between 1 and 10.

[0058] Each slab 40-1, ..., 40-N comprises a plurality of patterns 41-1, ..., 41-K arranged on an outer surface of this slab. As can be seen in FIG. 2, these patterns form for example at least two rows and at least two columns on the surface of the corresponding slab. According to other examples, the radiating elements can be arranged in a circle or have any other arrangement and the patterns can be adapted to this arrangement. The size of a pattern can be chosen to avoid an intra-pattern calibration of the radiating element by radiating element type for example. The number K of patterns per slab varies for example from 4 to 16.

[0059] Each pattern 41-1, ..., 41-K has, for example, a printed circuit on which a plurality of radiating elements are arranged. According to another example, the radiating elements may be horns. The patterns 41-1, ..., 41-K are, for example, substantially similar to each other. Thus, subsequently, only the pattern 41-1 will be explained in more detail with reference to FIG. 3.

[0060] With reference to this figure 3, the pattern 41-1 comprises a plurality of radiating elements 42-1, ..., 42-M. In the example of this figure, the number L of radiating elements is equal to 64. The radiating elements 42-1, ..., 42-M form a matrix on the corresponding pattern 41-1. Furthermore, the radiating elements 42-1, ..., 42-M are grouped into a plurality of groups within the same pattern 41-1. In the example of figure 3, each group is composed of four adjacent radiating elements 42-1, ..., 42-M. In this example, 16 groups of radiating elements are therefore formed. Each group of radiating elements is controlled by the same control unit, as will be explained in more detail later.

[0061] The beamforming module 32 is an analog module for generating an elementary signal to be transmitted for each radiating element 42-1, ..., 42-M from the radiofrequency signal delivered by the modem 33.

[0062] To do this, the beamforming module 32 comprises a transmission conversion unit 45, for example of the BUC (Block Up Converter) type, making it possible to convert the frequency of the radiofrequency signal delivered by the modem 33 into a frequency to be transmitted in a range, such as, for example, the “L”, “Ku” or “Ka” band.

[0063] The beamforming module 32 further comprises at least three levels of signal separators making it possible to generate an elementary signal for each radiating element 42-1, ..., 42-M. These separators have controllable gain amplifiers and programmable phase shifters (and / or delays) making it possible to generate a beam of elementary signals according to techniques known per se.

[0064] In particular, as can be seen in FIG. 2, a first level of separators comprises a single separator 51 for separating the signal delivered by the transmission conversion unit 45 between the tiles 40-1, ..., 41-N. A second level of separators comprises N separators 52-1, ..., 52-N. Each separator of the second level 52-1, ..., 52-N is associated with one of the tiles 40-1, ..., 40-N and makes it possible to separate the signal received by this tile between the different patterns 41-1, ..., 41-K. Finally, a third level of separators comprises, for each pattern 41-1, ..., 41-K in each tile 40-1, ..., 40-N, a separator 53 for separating the signal delivered to the corresponding pattern between the different groups of radiating elements forming this pattern. Such a separator 53 is visible in Figure 3.

[0065] The beamforming module 32 further comprises a control unit 55 associated with each group of radiating elements and making it possible to generate an elementary signal for each radiating element of this group from the signal delivered by the corresponding separator 53 of the third level.

[0066] An example of such a control unit 55 is shown in Figure 4. According to this example, the control unit 55 is associated with a group of radiating elements formed of four radiating elements 42-1, ..., 42-M. Thus, from a signal delivered by the corresponding separator 53, this unit 55 makes it possible to generate 4 elementary signals for the corresponding radiating elements 42-1, ..., 42-M, according to a predetermined logic. As indicated previously, the calibration system 10 is integrated in the antenna 11.

[0067] In particular, the calibration system 10 makes it possible to inject a calibration signal into a nominal signal to be emitted by the antenna 11 and then to receive via mutual coupling between at least certain radiating elements this calibration signal to compare it with the calibration signal initially emitted. The calibration is done by radiating element and to distinguish the calibration signal emitted by a given radiating element, a particular modulation is introduced into the elementary signal to be emitted by this radiating element.

[0068] To do this, the calibration system 10 comprises a calibration modem 57 integrated for example in the control module 34 of the antenna 11 and making it possible to generate a calibration signal to be transmitted by one or more radiating elements. According to an exemplary embodiment, this calibration modem 57 is capable of injecting the calibration signal into the radiofrequency signal generated by the modem 33. For this, a signal summing unit can be arranged upstream of the transmission conversion unit 45. In such a case, the calibration signal is summed with the nominal signal to be transmitted by the antenna 11. According to another exemplary embodiment, the calibration modem 57 is capable of injecting the calibration signal downstream of each separator 52-1, 52-N into the signal intended for the pattern corresponding to the radiating element to be tested or downstream of each separator 53 into the signal intended for the group of radiating elements corresponding to the radiating element to be tested.

[0069] The calibration system 10 further comprises a reception circuit connecting at least one radiating element of each pattern 41-1, ..., 41-K to the calibration modem 57. In particular, such a radiating element is hereinafter called a reception radiating element and is chosen from the radiating elements 42-1, ..., 42-M described previously. In the example of FIG. 3, a group of four reception radiating elements 58 is chosen from all the radiating elements 42-1, ..., 42-M of the pattern 41-1.

[0070] Advantageously, the receiving radiating elements 58 chosen in a pattern correspond to the same group of radiating elements and are therefore controlled by the same control unit 55. Possibly, only one of the four receiving radiating elements is used.

[0071] Even more advantageously, this control unit 55 is capable of switching the operating mode of the corresponding radiating elements 58 between the reception mode and the transmission mode. In certain embodiments, each radiating element 42-1, ..., 42-M can be switched between the reception mode and the transmission mode by the control unit 55 associated with this radiating element. The reception 58 and transmission radiating elements operate at the same frequency.

[0072] It is clear that the respective position of the receiving radiating elements 58 and the transmitting radiating elements determines the coupling between these elements. This coupling allows at least some receiving radiating elements 58 to receive elementary signals from at least some transmitting radiating elements. Advantageously, according to the invention, the coupling between each pair of radiating elements is known and for example stored in a dedicated database.

[0073] To connect the receiving radiating elements 58 to the receiving circuit, each pattern 41 -1, ..., 41 -K comprises for example a suitable Rx connector.

[0074] The reception circuit of the calibration system 10 further comprises a reception conversion unit 59. As can be seen in FIG. 2, this reception conversion unit 59 is integrated into the beamforming module 32 and its role is the opposite of that of the transmission conversion unit 45. In particular, the reception conversion unit 59 is for example also of the BUC type and makes it possible to convert signals received by the reception circuit into radiofrequency signals compatible with the calibration modem 57. In one embodiment, the reception conversion unit 59 and the transmission conversion unit 45 form a common unit given that transmission and reception are carried out at the same frequency.

[0075] Finally, the calibration system 10 comprises a control unit 60 capable of controlling the operation of the calibration modem 57 and of the reception circuit. This control unit 60 is integrated for example in the control module 34 of the antenna 11. The control unit 60 also makes it possible to introduce a particular modulation into the elementary signal emitted by each radiating transmission element, as will be explained in more detail later. To do this, the control unit 60 can be connected to each separator of each level of separators as well as to the control unit 55 of each group of radiating elements.

[0076] The calibration system 10 is capable of implementing at least certain steps of the method for calibrating the transmission array antenna 11. This method will now be described in detail with reference to FIG. 5 showing a flowchart of its steps.

[0077] The purpose of this method is to calibrate the radiating transmitting elements during operation in nominal mode of the transmitting array antenna 11. In other words, the steps described below are implemented during the transmission of useful data by the transmitting antenna 11 without significant degradation of the quality of its service. During an initial step 110, the calibration system 10 selects a radiating transmitting element to be tested.

[0078] The selection can be made, for example, according to a predetermined rule. This rule can, for example, include the selection of a radiating element according to an order defined by its position on the slab and / or the corresponding pattern.

[0079] According to a variant, during this step, the calibration system 10 selects several radiating transmitting elements to be tested. These radiating transmitting elements to be tested are for example from the same group or are neighbors. In such a case, the steps 115 to 160 described below are implemented in parallel for each of the radiating transmitting elements to be tested selected, using a particular modulation specific to each radiating transmitting element to be tested. The calibration signal therefore remains the same for all of the radiating transmitting elements to be tested. Step 130 also remains the same for all of the radiating transmitting elements to be tested.

[0080] In a following step 115, the calibration modem 57 generates a calibration signal and injects it in place of or in addition to the nominal elementary signal to be emitted by the radiating transmission element to be tested. Thus, subsequently, by elementary signal to be emitted by the radiating transmission element to be tested, we mean the calibration signal alone or combined with the nominal elementary signal to be emitted by this element.

[0081] According to various embodiments, the calibration signal can be injected at the modem 33 or at any separator described previously or at the control unit 55 associated with the radiating transmission element to be tested. Depending on the injection level, the elementary signals to be emitted from at least some radiating transmission elements can then be summed or replaced by the calibration signal.

[0082] In a following step 120, the control unit 60 introduces a particular modulation into the elementary signal to be emitted by the radiating transmission element to be tested. This can be done by, for example, directly controlling the control unit 55 associated with the radiating transmission element to be tested.

[0083] Furthermore, different techniques may be used to introduce this particular modulation only into one of the transmitting radiating elements among the set of transmitting radiating elements controlled by the corresponding control unit 55. For example, it is possible to attenuate the power level on the radiating elements other than the transmitting radiating element to be tested.

[0084] Another technique may be to emit several different particular modulations in parallel, one per radiating element of the group considered. In such a case, the elementary signals from the radiating elements other than the transmitting radiating element to be tested may be rejected or measured during step 150 described below, using these particular modulations.

[0085] The particular modulation may have an amplitude-phase, or amplitude / delay, or combined amplitude-phase-delay code which is superimposed on the elementary signal formed for the transmitting radiating element to be tested in the previous step.

[0086] For example, the particular modulation introduced into the elementary signal at this stage may be a code having good autocorrelation and / or cross-correlation properties.

[0087] During a following step 130, the transmission network antenna 11 transmits a beam of elementary signals (i.e. nominal elementary signals except those which have been modified by the calibration signal and possibly by the particular modulation) by all of the radiating elements 42-1, ..., 42-M.

[0088] In a following step 140, the calibration modem 57 uses one of the receiving radiating elements 58 to receive a signal formed from the transmitted beam.

[0089] The selection of this receiving radiating element 58 is made according to its position relative to the transmitting radiating element to be tested. For example, the selection is made so that the receiving radiating element 58 has maximum coupling with the transmitting radiating element to be tested.

[0090] According to various examples of the invention, the receiving radiating element 58 is selected so as to be:

[0091] - in the same pattern as the radiating emission element to be tested; or

[0092] - in the same slab as the radiating emission element to be tested but in a different pattern; or

[0093] - in a slab other than the slab of the radiating emission element to be tested.

[0094] According to one embodiment, the selection of the receiving radiating element 58 is done dynamically from among the set of radiating elements 42-1, ..., 42-M. In such a case, the calibration system 10 can for example select one of the radiating elements 42-1, ..., 42-M other than the radiating element to be tested and then switch it into the receiving mode.

[0095] According to another embodiment, the selection of the receiving radiating element 58 is made from a predetermined set of radiating elements operating in receiving mode. This set is for example predetermined statically, for example for the entire life cycle of the antenna. In the latter case, the elements of this set always operate for example in receiving mode.

[0096] In some embodiments, the receiving radiating element 58 may be part of a group of receiving radiating elements. In such a case, only this radiating element in the group, for example, may be used, the others being attenuated as much as possible or each of the receiving radiating elements is used.

[0097] During a following step 150, the control unit 60 separates the elementary signal received from the radiating emission element to be tested from the other elementary signals by applying the code corresponding to the particular modulation introduced during transmission.

[0098] The implementation of steps 120 to 150 is schematically illustrated in Figure 6.

[0099] In particular, in this figure, the element Rxk (p,q) corresponds to the receiving radiating element 58, the element Txk(i,j) corresponds to the radiating element to be tested and the element Tx u (r,s) corresponds to any other radiating emission element exhibiting mutual coupling with the Rxk element (p,q). It is clear that in practice, several Tx elements u (r,s) exhibit mutual coupling with the Rxk element (p,q). However, to facilitate understanding of Figure 6, only one Tx element u (r,s) is represented there.

[0100] The nominal elementary signal to be emitted by the two Tx elements k (i,j) and Tx u (r,s) is controlled by the control bus SPI_k introducing the code CTx(i,j), and SPI_u in Figure 6 respectively. The signal Ka_Tx k , sum of the nominal signal and the calibration signal or only the calibration signal, is multiplied by the nominal signal CTx(i,j) of the element Txk(i,j). Moreover, in the example of this figure, the signal Ka_Tx u , sum of nominal signal and calibration signal like Ka_Txk, or only nominal signal is not modulated by any particular modulation.

[0101] The elementary signals emitted by the two Tx elements then form a beam of elementary signals which is received by the receiving radiating element Rxk (p,q) thanks to the mutual coupling with each of the illustrated Tx elements. Such mutual coupling is denoted in Figure 6 as MC(ij,pq) and MC(rs,pq).

[0102] Finally, in the example of Figure 6, the code CRx(p,q) is used to extract from the emitted beam the elementary signal emitted by the radiating element Txk(i,j).

[0103] In another example, several different CRx(p,q) codes are used, if several transmitting radiating elements are tested in parallel, but applied and distributed over several receiving radiating elements, via the SPI_k' control, or applied in parallel during the calibration demodulation.

[0104] In a following step 155, the control unit 60 compares the elementary signal extracted in the previous step with the elementary signal emitted by the radiating transmitting element to be tested. This is possible because the calibration modem 57 knows the calibration signal emitted as well as the time of its transmission. This comparison may include, for example, a measurement of the difference in phase, delay, amplitude between the calibration signal which has been emitted and that received via coupling between the radiating transmitting element to be tested and the radiating receiving element 58 allowing the analysis of the variations with respect to the calibration table.

[0105] In this step, several measurements of multiple durations of the code length on the extracted signal can for example be made to improve accuracy. The number of measurements is advantageously greater than 1 and less than for example 10 or 100.

[0106] In the following step 160, the control unit 60 analyzes the previous comparison and corrects the calibration parameters of the radiating element to be tested. In particular, these parameters are for example corrected so as to minimize the difference between the calibration signal which was transmitted and that received.

[0107] Then, steps 110 to 160 are repeated in relation to another radiating element.

[0108] It is therefore understood that the present invention presents a certain number of advantages.

[0109] In particular, the invention makes it possible to calibrate a transmitting array antenna throughout its life cycle without degradation of the service provided. Indeed, during calibration, the transmitting array antenna operates normally and the calibration signal introduced at one or more radiating elements does not degrade the quality of service provided by this antenna. A particular modulation is used to distinguish the elementary signals emitted by different radiating elements and thus makes it possible to calibrate each of the radiating elements one by one. In addition, the method according to the invention can be applied an unlimited number of times for all the radiating elements. Each calibration signal introduced can be controlled and varied, for example, to adapt the calibration to a particular type of variation that may occur throughout the life cycle of the array antenna.This calibration can be carried out by the antenna autonomously, i.e. without using any other means. Finally, thanks to the invention, it is also possible to test several radiating emission elements in parallel. To do this, it is sufficient to apply a particular modulation specific to each of the radiating elements to be tested.

Claims

CLAIMS 1. Method for calibrating a phased array transmitting antenna (11) of the AESA type, the transmitting array antenna (11) comprising: - a plurality of radiating emission elements; - at least one receiving radiating element (58) arranged among the transmitting radiating elements; - an analog beamforming module (32) capable of forming for each radiating emission element an elementary nominal signal to be emitted from a radiofrequency signal; - a modem (33) capable of generating the radiofrequency signal; the method comprising the following steps: - selection (1 10) of at least one radiating emission element to be tested; - formation (1 15) of an elementary signal to be emitted by the radiating emission element to be tested by injecting a calibration signal in place of or in addition to the nominal elementary signal to be emitted by this radiating emission element to be tested; - introduction (120) of a particular modulation into the elementary signal to be emitted by the radiating emission element to be tested; - emission (130) of a beam of elementary signals by all of the radiating emission elements (42-1, 42-M); - reception (140) by the receiving radiating element (58) of a signal formed from the beam emitted via a coupling between the transmitting radiating element to be tested and this receiving radiating element (58); - extraction (150) of the received signal from an elementary signal emitted corresponding to the radiating emission element to be tested using the particular modulation; - comparison (155) of the extracted elementary signal with the elementary signal emitted by the radiating emission element to be tested; - correction (160) of calibration parameters of the radiating emission element to be tested as a function of said comparison.

2. Method according to claim 1, in which the steps of the method are repeated for each radiating transmitting element of the transmitting array antenna (11) to be calibrated.

3. Method according to any one of the preceding claims, in which the steps of the method are repeated during operation of the transmitting array antenna (11) in nominal mode.

4. Method according to any one of the preceding claims, in which the introduction of the particular modulation comprises the introduction into the elementary signal to be emitted by the radiating emission element to be tested of a code in phase and / or in delay and / or in amplitude.

5. Method according to any one of the preceding claims, in which when during the selection step (110) several radiating transmission elements to be tested are selected, the other steps of the method are implemented in parallel for each of the radiating transmission elements to be tested selected using a modulation specific to each of the radiating transmission elements to be tested.

6. Method according to any one of the preceding claims, in which the calibration parameters of a transmitting radiating element comprise phase and / or delay and / or amplitude weights associated with this transmitting radiating element.

7. A method according to any preceding claim, wherein the receiving radiating element (58) operates at the same frequency as the transmitting radiating element to be tested.

8. Method according to any one of the preceding claims, in which the receiving radiating element (35) is arranged according to one of the possibilities: - in the same pattern (41-1, ..., 41-K) as the radiating emission element to be tested; - in the same slab (40-1, ..., 40-N) as the radiating emission element to be tested but in a different pattern (41-1, ..., 41-K); - in a slab (40-1, ..., 40-N) other than the slab of the radiating emission element to be tested.

9. Method according to any one of the preceding claims, in which the step of comparing (155) the extracted elementary signal with the elementary signal emitted by the radiating emission element to be tested comprises a measurement of the difference in phase and / or delay and / or amplitude between the calibration signal emitted and that received via coupling between the transmitting radiating element to be tested and the receiving radiating element (58).

10. Method according to any one of the preceding claims, in which the calibration signal is injected into a nominal signal to be transmitted by the transmission network antenna (11) at the modem (33) or at a pattern (41 -1, ..., 41 -K) comprising the transmission radiating element to be tested.

11. Calibration system (10) of a phased array transmitting antenna (11) of the AESA type, configured to implement the method according to any one of the preceding claims.

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