EQUIPMENT AND METHOD FOR SELF-CALIBRATION OF A NETWORK

ANTENNAS

TECHNICAL AREA

The present invention relates to the technical field of antenna arrays for space-time processing. The present invention relates more particularly to a method for self-calibration of an antenna array for spatiotemporal processing.

STATE OF THE PRIOR ART

An antenna array is a device comprising a plurality of separate radio antennas, positioned relative to each other in a predetermined manner. An array of antennas can be used to receive a radio signal (hereafter radio signal), each antenna receiving said radio signal with a phase shift and/or an attenuation specific to its position, and converting said radio signal into an electrical signal. The plurality of electrical signals from the antenna array is transmitted to an electronic device suitable for combining these electrical signals. It is then possible to implement so-called “beam forming” techniques (or also “spatial filtering”, "path formation" or even "beamforming" in English) in order to modify a radiation pattern of the antenna array in one or more directions. It is thus possible to greatly attenuate a gain of the antenna array in the direction of one or more radio sources (technique known as “nulling” in English) and/or to increase the gain of the antenna array in the direction of other sources of radio signals (technique known as "beamforming" or "beammastering" in English).

If an array of antennas, thanks to beamforming techniques, can offer superior performance to an isolated antenna, this array of antennas nevertheless needs to be calibrated in gain and in phase in order to operate optimally.

Each antenna of an antenna array is associated with a set of components making it possible to transmit the electrical signal from the antenna to the electronic device for combining the electrical signals from the plurality of antennas (hereafter, a unit of processing). This set of components can include filters, amplifiers, attenuators, mixers or any other electronic component making it possible to process an electrical signal. This set of components is called the receive channel. Thus, each antenna is connected via a reception path associated with the electronic device for combining electrical signals or processing unit. The different components of the transmission paths can be particularly dispersive, for example because of variability of the characteristics from one component to another or because of variability according to the temperature of use of a component. It is nevertheless necessary for the gain and/or phase shift characteristics of each reception channel to be as close as possible in order to optimize the implementation by the processing unit of the beam forming techniques.

A first known solution to this problem of calibrating an antenna array is illustrated in Fig. 1. FIG. 1 schematically illustrates a functional solution for calibrating equipment comprising an antenna array according to a first known embodiment. The antenna array here comprises three antennas 101, 102 and 103, the solution being applicable to any other different number of antennas used. The antenna 101, respectively the antenna 102 or 103, is connected to the processing unit 120 via a reception channel 110, respectively a reception channel 111 or 112. The calibration is done by means of a source of radio signal 150, called reference source 150, suitable for transmitting a so-called reference radio signal. The reference source 150 is arranged outside the equipment comprising the antenna array, at a distance “d”, this distance “d” being large enough for the radio signal coming from the reference source 150 to be able to be considered at the level of the antenna array as a far field. In other words, the antenna array must be in an area known as the "Fraunhofer region" with respect to the reference source, that is to say a distance greater than the equivalent of several wavelengths of the reference radio signal used. The reference source 150 is seen from the antenna array at an angle "Q". The first solution requires that the distance “d” and the angle “Q” be constant during the calibration, which can be problematic if the equipment comprising the antenna array is in motion. The reference radio signal is received by each antenna,

processing 120. The measurement unit 130 is suitable for measuring a difference in gain and/or phase shift between each electrical signal picked up. The measurement unit 130 can supply the results of the measurements to a compensation device 140 adapted to modify the gain and/or phase of each reception channel 110, 111 and 112 in order to compensate for the differences in gain and/or phases measured according to of the angle "Q" under which the reference source 150 is seen.

This first solution, called “in radiated mode”, has the following drawbacks:

a dependence on an external reference source, complicating the implementation of the calibration, especially for equipment comprising the array of antennas in motion,

the reference source 150 must be placed at an angle “Q” with respect to the antenna array, this angle having to be known and/or measurable and fixed during the calibration phase, which again can be complicated,

- the reference source 150 must be placed at a certain distance “d” from the equipment in order to guarantee emission from the reference source 150 in the far field, this distance again having to be fixed during the calibration phase.

In the end, this first calibration solution is operationally very restrictive.

A second solution is illustrated in Fig. 2. This second solution differs from the first solution by the use of an internal reference source 160 instead of the external reference source 150. In other words, the reference source 160 is placed in the equipment comprising the antenna array. A reference radio signal emitted by the reference source 160 is injected into each reception channel 110, 111 and 113, for example by means of radio couplers 171, 172 and 173. Similarly to the first solution, a measurement unit (not shown) and a compensation device (not shown) make it possible to measure the differences in gain and/or phase at the output of the reception channels and to compensate for them.

This second solution, called “in driven mode”, has the following drawbacks:

the antennas 101, 102 and 103 are not taken into account during a calibration phase, the reference signal being injected at the output of each antenna, the radio couplers 171, 172 and 173 can themselves introduce differences in gain and/or phase at the input of the reception channels,

the calibration phase cannot be carried out in operational condition, the reference signal disturbing the processing carried out by the processing unit.

Thus, it is necessary to present a solution allowing calibration of equipment comprising an antenna array, this calibration having to:

take into account a maximum of the constituent elements of the reception chain, from each antenna to the processing unit,

- be as resistant as possible to errors in the reference signal (e.g. bad placement or displacement of the external reference source), guarantee autonomy of the equipment including the antenna array for its calibration, calibration that can be carried out in possibly degraded operational conditions.

DISCLOSURE OF THE INVENTION

The invention relates to equipment comprising an array of radioelectric antennas, each antenna being connected via at least one reception channel associated with a processing unit adapted to implement a technique for forming beams, the equipment comprising a device for switch placed as a cut-off between the antennas and the associated reception channels, the switch device comprising:

- input interfaces in the same number as the antennas, each input interface allowing connection of an antenna,

- output interfaces in the same number as the reception channels, each output interface allowing connection of a reception channel, the switching device comprising two modes of operation:

- a first so-called operational operating mode, each input interface then being connected directly to a different output interface in order to connect each antenna with at least its associated reception channel,

- a second so-called calibration operating mode, an input interface corresponding to a predetermined antenna then being connected to

all of the output interfaces in order to transmit the electrical signal from the predetermined antenna to all of the reception channels, the equipment being suitable for carrying out a process for calibrating the reception channels when the switching device is in the second operating mode.

According to one embodiment of the invention, the equipment comprises:

- a measurement unit, suitable for capturing an electrical signal at the output of each reception channel and determining the physical parameters associated with said electrical signal,

- a compensation device, suitable for configuring each reception channel according to the physical parameters associated with the electrical signals determined at the output of the reception channels.

According to one embodiment of the invention, the switching device comprises:

- a chain of electrical signal divider elements, each divider element comprising an input and two outputs, the input of the first divider element of the chain being connected to the input interface of the predetermined antenna, an output of the first divider element being connected to the output interface corresponding to the input interface, the chain of divider elements being suitable for dividing the electric signal coming from the input interface connected to the predetermined antenna into as many signals electric than reception channels,

- switches, each switch comprising two inputs and one output, the outputs of the switches being connected to each output interface, except that corresponding to the reception channel of the predetermined antenna, each input of the switches being connected to an interface of input and to a divider element of the chain of divider elements, the switch element making it possible to connect one or the other of these two inputs to the output interface,

the switches being suitable for:

o in the first mode of operation, transmitting the electrical signal from each input interface to at least one output interface, each antenna then being connected to at least its associated reception channel,

o in the second mode of operation, transmitting the electrical signal from the divider element, the predetermined antenna then being connected to all of the reception channels.

According to one embodiment of the invention, the equipment comprises:

- an electric signal splitter element connected to each input interface, except that connected to the predetermined antenna, an output of the splitter element being connected to the switch connected to the output interface corresponding to the input interface , the other output being connected to a predetermined impedance matching load,

- a divider element and a switch connected in series, the outputs of the divider element being connected to the inputs of the switch, and placed in cut-off between the output of the first divider element connected to the output interface corresponding to the interface of input and said output interface.

The invention also relates to a method for self-calibration of the equipment comprising an array of radioelectric antennas, the method comprising the steps of:

- switch the switching device to the second mode of operation,

- capture an electrical signal at the output of each reception channel,

- determining physical parameters associated with said electrical signals,

- configure each reception channel according to the physical parameters associated with the electrical signals determined at the output of the reception channels,

- Toggle the switching device in the first mode of operation.

The invention also relates to a computer program comprising instructions for implementing, by a processor of the equipment comprising a network of radioelectric antennas, the method of self-calibration of the equipment, when the program of computer is run by the processor.

The invention also relates to a recording medium, possibly readable by the equipment, on which said computer program is stored.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics of the invention mentioned above, as well as others, will appear more clearly on reading the following description of an exemplary embodiment, said description being made in relation to the attached drawings, among which:

[Fig. 1] schematically illustrates a functional solution for calibrating equipment comprising an antenna array according to a first known embodiment,

[Fig. 2] schematically illustrates a functional solution for calibrating equipment comprising an antenna array according to a second known embodiment,

[Fig. 3] schematically illustrates a functional solution for calibrating equipment comprising an antenna array according to one embodiment of the invention,

[Fig. 4] schematically illustrates an architecture of a switching device for a calibration solution according to a first embodiment of the invention,

[Fig. 5] schematically illustrates an architecture of a switching device for a calibration solution according to a second embodiment of the invention,

[Fig. 6] schematically illustrates a hardware architecture of equipment for a calibration solution according to one embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Fig. 3 schematically illustrates a functional solution for calibrating equipment comprising an array of antennas 101, 102, 103 according to one embodiment of the invention.

The equipment illustrated in FIG. 3 comprises an array of radio antennas 101, 102 and 103. According to the embodiment of the invention, the antenna array may comprise any plurality of antennas. Each antenna 101, 102 and 103 is connected via at least one reception channel 110, 111, 112 associated with the processing unit 120 adapted to implement a beam forming technique. The equipment comprises a switching device 200 placed as a cut-off between the antennas 101, 102, 103 and the associated reception channels 110, 111, 112. The equipment illustrated in FIG. 3 therefore differs from the equipment illustrated in FIG. 1 and the equipment illustrated in FIG. 2 by the presence of the switching device 200 placed in cut-off between the antennas 101, 102 and 103 and the reception channels 110, 111 and 112.

Similarly, the reception channel 110, respectively the reception channel 111 or 112, is connected to an output interface "1" of the switching device 200, respectively an output interface "2" or "3" of the switching device. referral.

The switching device 200 comprises:

- input interfaces ("A", "B" and "C") in the same number as the antennas 101, 102, 103, each input interface allowing connection of an antenna,

- output interfaces ("1", "2", "3") in the same number as the reception channels 110, 111, 112, each output interface allowing connection of a reception channel.

In other words, the switching device 200 is placed as a cut-off between the antennas and their associated reception channels. An input interface of the routing device 200 then corresponds to an output interface of the routing device 200 in the sense that said input interface is connected to an antenna and said output interface is connected to the reception channel. associated with said antenna.

The switching device 200 comprises two modes of operation:

- a first so-called operational operating mode, each input interface then being connected directly to a different output interface in order to connect each antenna with at least its associated reception channel,

- a second mode of operation called calibration, an input interface corresponding to a predetermined antenna then being connected to all the output interfaces in order to transmit the electrical signal from the predetermined antenna to all the channels reception.

Thus, in the first mode of operation, the operation of the switching device 200 is transparent in the sense that the electrical signal from each antenna is transmitted directly to the reception channel associated with said antenna. The operation of the equipment is in this mode of operation similar to that of equipment which would not include a switching device, each antenna being directly connected to its respective reception channel.

In the second operating mode, the electrical signal coming from a predetermined antenna, called the reference antenna, is distributed over all the reception channels. This electrical signal from the reference antenna is distributed instead of the signals received by the other antennas. Each reception channel then receives the same electrical signal from the same reference antenna.

By same electrical signal is meant an electrical signal of the same phase, but possibly of different power. The power of each electrical signal output from the output interfaces of the switching device can vary. The switching device 200 can attenuate in a different, but predetermined way, the electric signal received from the reference antenna at the output of each of its output interfaces.

The equipment is suitable for carrying out a method for calibrating the reception channels when the switching device is in the second mode of operation. This calibration process includes the steps of:

- switch the switching device to the second mode of operation,

- capture an electrical signal at the output of each reception channel,

- determining physical parameters associated with said electrical signals, - configuring each reception channel according to the physical parameters associated with the electrical signals determined at the output of the reception channels,

- Toggle the switching device in the first mode of operation.

In the second operating mode, the equipment therefore uses as a calibration source the radio signal received by a predetermined antenna or reference antenna. The choice of this antenna is arbitrary among the plurality of antennas of the antenna array.

In the absence of a particular radio signal in the environment of the equipment, the radio signal received by each antenna of the antenna array is comparable to thermal noise and is different for each antenna. It would therefore not be possible to calibrate the antenna array using the signals received by each antenna, these being different. On the other hand, the equipment disclosed in this document, by selecting the radio signal from a single predetermined antenna and by distributing this same signal over all the reception channels, makes it possible to guarantee the use of an identical signal on each channel of reception, and therefore allows a calibration of the reception channels. According to one embodiment of the invention, the antennas of the antenna array are calibrated beforehand in order to have identical characteristics.

In the presence of a particular radio signal in the environment of the equipment, each antenna can therefore receive this same radio signal. However, it is not possible to use this radio signal to calibrate the antenna array, the

positioning characteristics of the radio signal source being unknown (incident angle “Q” or distance “d” from the source, see Fig. 1).

Thus, whether in the absence or in the presence of a radio signal, the equipment disclosed makes it possible to carry out a self-calibration of the reception channels. The solution does not rely on an external source (cf. external source 150 in Fig. 1), nor on an internal source (cf. internal source 160 in Fig. 2), which simplifies the technical architecture of the equipment.

It should be noted that in the second mode of operation, the radio signal received by the reference antenna is ultimately transmitted to the processing unit 120. This means that in the second mode of operation, the equipment can continue to receive a radio signal and is therefore operational. Only the implementation of beamforming techniques is not possible in the second mode of operation. This has an advantage over the known solution shown in Fig. 2, this solution using an internal reference source not making it possible to continue to receive a radio signal during the calibration phase, the reference or calibration signal disturbing the reception of other radio signals.

It should also be noted that obviously, the solution presented in Fig. 3 makes it possible to dispense with an external reference source and is therefore operationally easier to implement than the solution presented in FIG. 1 with the external reference source 150.

According to one embodiment of the invention, the equipment comprises:

- a measurement unit 130, suitable for capturing an electrical signal at the output of each reception channel and determining the physical parameters associated with said electrical signal,

- a compensation device 140, suitable for configuring each reception channel according to the physical parameters associated with the electrical signals determined at the output of the reception channels.

According to an alternative embodiment of the invention, the processing unit 120 integrates the measurement unit 130 and/or the compensation device 140.

Fig. 4 schematically illustrates an architecture of a switching device

200 for a calibration solution according to a first embodiment of the invention. In this example, as well as for the example illustrated below in FIG. 5, the predetermined antenna, or reference antenna, is arbitrarily chosen as being connected to the "A" input interface of the switching device 200. The

routing device 200 may in particular comprise electrical signal divider elements and switches.

An electrical signal splitter - or power splitter - element has three ports: one input port and two output ports. An electrical signal divider element makes it possible to divide the power of the electrical signal arriving at the input port by distributing it to the two output ports. Thus, each output port of the electric signal splitter element outputs an electric signal similar to the electric signal applied to the input port, the power of the output signal being however divided by two compared to the power of the electric signal at the input of the electrical signal divider element. An electrical signal dividing element is for example a “Wilkinson divider”.

A switch comprises a plurality of input ports, each input port being able to receive an electrical signal from a source connected to said input port, and is adapted to select an electrical signal received on one of the ports of 'Entrance. The electrical signal selected, ie corresponding to the selected input port, is redirected to an output port. A switch can for example comprise two input ports and one output port. The switch is then adapted to redirect the electrical signal received on one or other of the input ports to the output port. In other words, the switch makes it possible to select at the output one or the other of the electrical signals received at the input.

The switching device 200 can thus comprise:

- a chain of electrical signal divider elements 300, 310, each divider element 300, 310 comprising one input and two outputs, the input of the first divider element 300 of the chain being connected to the input interface "A" of the predetermined antenna, an output of the first divider element being connected to the output interface "1" corresponding to the input interface "A", the chain of divider elements 300, 310 being adapted to divide the signal electrical output from the "A" input interface connected to the predetermined antenna in as many electrical signals as there are reception channels,

- switches 320, 321, each switch 320 and 321 comprising two inputs and one output, the outputs of the switches being connected to each output interface "2" and "3" (except output "1" corresponding to the reception channel of the predetermined antenna), each input of the switches

being connected to an input interface "B" and "C" and to a divider element 310 of the chain of divider elements, the switch element 320 or 321 making it possible to connect one or the other of these two inputs to output interface "2" or "3".

The 320 and 321 switches are suitable for:

o in the first operating mode, transmitting the electrical signal from each input interface "A", "B" and "C" to an output interface "1", "2" and "3", each antenna 101 , 102, 103 then being connected to its associated reception channel 110, 111, 112,

o in the second mode of operation, transmitting the electrical signal from the divider element 310, the predetermined antenna then being connected to all of the reception channels 110, 111 and 112.

In Fig. 4, the dotted line symbolically represents the path of the electrical signal coming from the reference antenna connected to the input interface "A" and having been "divided" by the first divider element 300 and then by the second divider element 310 chain. This electric signal shown in dotted lines therefore arrives at the input of the switches 320 and 321, these two switches 320 and 321 being suitable for, in the second mode of operation, transmitting this electric signal coming from the divider element 310 to the output interfaces "2 and “3”.

Fig. 5 schematically illustrates an architecture of a switching device 200 for a calibration solution according to a second embodiment of the invention. In this example, as well as for the example previously illustrated in FIG. 4, the predetermined antenna, or reference antenna, is arbitrarily chosen as being connected to the "A" input interface of the routing device 200. According to this second embodiment, the routing device 200 illustrated in Fig. 4 is perfected. This improvement includes:

- an addition of a divider element 311 and a switch 322 in series between the output of the divider element 300 and of the output interface "1", and,

- an addition of dividers 301, 302, 312 and 313, an output of each of these dividers 301, 302, 312 and 313 being connected to a predetermined impedance matching load 330, 331, 332 and 333.

The value of the predetermined impedance matching load 330, 331, 332 and 333 is typically that of the characteristic impedance of the equipment, for example 50 W.

These additions of dividers and switches make it possible to guarantee that each connection between an "A", "B" or "C" input interface of the switching device 200 and an output interface "1", "2" or "3" pass through the same types of electronic components in the first mode of operation and in the second mode of operation. Thus, each chain of electronic components, that is to say the electronic components between a given input and a corresponding output of the switching device 200, is identical, whether in the first mode of operation or in the second mode. Operating.

Thus, in the case illustrated in FIG. 5, and in the case of the first operating mode:

an electrical signal arriving from the input interface "A" passes through to reach the output interface "1": the first divider element 300 of the chain of divider elements 300 and 310, the divider element 311 and the switch 322,

an electrical signal arriving from the input interface "B" crosses to reach the output interface "2": the divider element 301, the divider element 312 and the switch 320, and,

an electrical signal arriving from the input interface "C" crosses to reach the output interface "3": the divider element 302, the divider element 313 and the switch 321.

Each signal arriving via an “A”, “B” or “C” input port therefore passes through a chain of identical electronic components, comprising two divider elements and a switch.

Similarly, in the case illustrated in Fig. 5, and in the case of the second operating mode:

a reference electrical signal arriving from the input interface "A" passes through to reach the output interface "1": the first divider element 300 of the chain of divider elements 300 and 310, the divider element 311 and switch 322,

this same reference electrical signal crosses to reach the output interface "2": the divider element 300, the divider element 310 and the switch 320, and,

this same reference electrical signal crosses to reach the output interface "3": the divider element 300, the divider element 310 and the switch 321.

Thus, the signal from the reference antenna connected to the "A" input interface passes through a chain of components comprising identical components before being distributed over the various reception channels "1", "2" and "3", which makes it possible to guarantee a balancing of the possible disturbances of the electrical reference signal during the crossing of the switching device 200.

The dividing elements 301 and 302, similar to the dividing element 300, as well as the matching loads 330 and 331, make it possible to obtain a balancing of the gain and of the phases between the different channels.

The examples given in Fig. 4 and in FIG. 5 are illustrated for an antenna array comprising three antennas. These examples are not limiting and can be implemented for antenna arrays comprising only two antennas, or on the contrary comprising more than three antennas.

The solutions presented therefore allow autonomous calibration of the equipment, without requiring an external source. This calibration can be carried out when the equipment is operational, the reception of a radio signal not being disturbed. Only one beamforming implementation is unavailable for the duration of the calibration. This calibration method can therefore be implemented—periodically or on demand—without disturbing continuity of service. The calibration process can thus be triggered when a predetermined variation in the internal temperature of the equipment is detected.

Fig. 6 schematically illustrates the hardware architecture of equipment 600 comprising a network of radio antennas, each antenna being connected via at least one reception channel associated with a processing unit suitable for implementing a beam forming technique, the the equipment being characterized in that it comprises a switching device placed as a cut-off between the antennas and the associated reception channels. The equipment is suitable for carrying out all or part of the steps of a self-calibration process. Equipment 600 may be the equipment illustrated in FIG. 3, this equipment 600 comprising the switching device 200 previously described.

Thus, the electronic device 600 comprises, connected by a communication bus: a processor or CPU (“Central Processing Unit” in English) 601; a memory MEM 602 of the RAM (Random Access Memory) and/or ROM (Read Only Memory) type, possibly at least one analog-digital converter CAN 603, a storage module STCK 604 of the storage type and possibly a plurality of antennas 605 to 60N connected to the analog-digital converter CAN 603. The storage module STCK 604 can be of the hard disk type HDD (“Hard Disk Drive”) or SSD (“Solid-State Drive”). in English), or of the external storage medium reader type, such as an SD (“Secure Digital” in English) card reader. The CPU 601 processor can record data, or information, in the memory MEM 602 or in the storage module STCK 604. The processor CPU 601 can read data recorded in the memory MEM 602 or in the storage module STCK 604. These data can correspond to configuration parameters. The analog-digital converter CAN 603 allows the conversion of an analog electrical signal coming from an antenna 605 at 60N into a digital signal that can be processed by the processor CPU 601 or by a dedicated electronic component, for example a microprocessor dedicated to the processing of the signal (or "DSP" for "Digital Signal Processor" in English), a component dedicated to signal processing (or "ASIC" for "Application Specifies Integrated Circuit" in English) or even a programmable electronic component (or "FPGA" for “Field Programmable Gate Array” in English). The processor CPU 601 can read data recorded in the memory MEM 602 or in the storage module STCK 604. These data can correspond to configuration parameters. The analog-digital converter CAN 603 allows the conversion of an analog electrical signal coming from an antenna 605 at 60N into a digital signal that can be processed by the processor CPU 601 or by a dedicated electronic component, for example a microprocessor dedicated to the processing of the signal (or "DSP" for "Digital Signal Processor" in English), a component dedicated to signal processing (or "ASIC" for "Application Specifies Integrated Circuit" in English) or even a programmable electronic component (or "FPGA" for “Field Programmable Gate Array” in English). The processor CPU 601 can read data recorded in the memory MEM 602 or in the storage module STCK 604. These data can correspond to configuration parameters. The analog-digital converter CAN 603 allows the conversion of an analog electrical signal coming from an antenna 605 at 60N into a digital signal that can be processed by the processor CPU 601 or by a dedicated electronic component, for example a microprocessor dedicated to the processing of the signal (or "DSP" for "Digital Signal Processor" in English), a component dedicated to signal processing (or "ASIC" for "Application Specifies Integrated Circuit" in English) or even a programmable electronic component (or "FPGA" for “Field Programmable Gate Array” in English). This data may correspond to configuration parameters. The analog-digital converter CAN 603 allows the conversion of an analog electrical signal coming from an antenna 605 at 60N into a digital signal that can be processed by the processor CPU 601 or by a dedicated electronic component, for example a microprocessor dedicated to the processing of the signal (or "DSP" for "Digital Signal Processor" in English), a component dedicated to signal processing (or "ASIC" for "Application Specifies Integrated Circuit" in English) or even a programmable electronic component (or "FPGA" for “Field Programmable Gate Array” in English). This data may correspond to configuration parameters. The analog-digital converter CAN 603 allows the conversion of an analog electrical signal coming from an antenna 605 at 60N into a digital signal that can be processed by the processor CPU 601 or by a dedicated electronic component, for example a microprocessor dedicated to the processing of the signal (or "DSP" for "Digital Signal Processor" in English), a component dedicated to signal processing (or "ASIC" for "Application Specifies Integrated Circuit" in English) or even a programmable electronic component (or "FPGA" for “Field Programmable Gate Array” in English).

The processor CPU 601 is capable of executing instructions loaded into the memory MEM 602, for example from the storage module STCK 604. When the equipment 600 is powered up, the processor CPU 601 is capable of reading memory MEM 602 instructions and execute them. These instructions form a computer program causing the implementation, by the processor CPU 601, of all or part of the methods and steps described above, particularly the self-calibration method. Thus, all or part of the methods and steps described above can be implemented in software form by execution of a set of instructions by a programmable machine, such as a DSP (Digital Signal Processor) or a microcontroller . All or part of the processes,

CLAIMS

1. Equipment (600) comprising an array of radio antennas (101, 102, 103, 605...60N), each antenna being connected via at least one associated reception channel (110, 111, 112) to a processing (120) suitable for implementing a technique for forming beams, the equipment being characterized in that it comprises a switching device (200) placed as a cut-off between the antennas and the associated reception channels, the device referral including:

- input interfaces (A, B, C) in the same number as the antennas, each input interface allowing connection of an antenna,

- output interfaces (1, 2, 3) in the same number as the reception channels, each output interface allowing connection of a reception channel, the switching device comprising two modes of operation:

- a first so-called operational operating mode, each input interface then being connected directly to a different output interface in order to connect each antenna with at least its associated reception channel,

- a second mode of operation called calibration, an input interface corresponding to a predetermined antenna then being connected to all the output interfaces in order to transmit the electrical signal from the predetermined antenna to all the channels reception, the equipment being suitable for carrying out a process for calibrating the reception channels when the switching device is in the second mode of operation.

2. Equipment according to the preceding claim, the equipment comprising:

- a measurement unit (130), suitable for capturing an electrical signal at the output of each reception channel and determining physical parameters associated with said electrical signal,

- a compensation device (140), suitable for configuring each reception channel according to the physical parameters associated with the electrical signals determined at the output of the reception channels.

3. Equipment according to one of the preceding claims, the switching device comprising:

- a chain of electrical signal dividing elements (300, 310), each dividing element comprising an input and two outputs, the input of the first dividing element of the chain being connected to the input interface of the predetermined antenna , an output of the first divider element being connected to the output interface corresponding to the input interface, the chain of divider elements being suitable for dividing the electrical signal coming from the input interface connected to the antenna predetermined in as many electrical signals as there are reception channels,

- switches (320, 321, 322), each switch comprising two inputs and one output, the outputs of the switches being connected to each output interface, except that corresponding to the reception channel of the predetermined antenna, each input of the switches being connected to an input interface and to a divider element of the chain of divider elements, the switch element making it possible to connect one or the other of these two inputs to the output interface,

the switches being suitable for:

o in the first mode of operation, transmitting the electrical signal from each input interface to at least one output interface, each antenna then being connected to at least its associated reception channel,

o in the second mode of operation, transmitting the electrical signal from the divider element, the predetermined antenna then being connected to all of the reception channels.

4. Equipment according to the preceding claim, the equipment comprising:

- an electric signal splitter element (301, 302) connected to each input interface, except that connected to the predetermined antenna, an output of the splitter element being connected to the switch connected to the output interface corresponding to the input interface, the other output being connected to a predetermined impedance matching load,

- a divider element and a switch connected in series (311, 322), the outputs of the divider element being connected to the inputs of the switch, and placed in cut-off between the output of the first divider element connected to the output interface corresponding to the input interface and said output interface.

5. Method for self-calibration of equipment (600) comprising an array of radioelectric antennas (101, 102, 103, 605...60N), each antenna being connected via at least one associated reception channel (110 , 111, 112) to a processing unit (120) suitable for implementing a technique for forming beams, characterized in that the equipment comprises a switching device (200) placed as a cut-off between the antennas and the channels associated receiving devices, the switching device comprising:

- input interfaces (A, B, C) in the same number as the antennas, each input interface allowing connection of an antenna,

- output interfaces (1, 2, 3) in the same number as the reception channels, each output interface allowing connection of a reception channel, the switching device comprising two modes of operation:

- a first so-called operational operating mode, each input interface then being connected directly to a different output interface in order to connect each antenna with at least its associated reception channel,

- a second mode of operation called calibration, an input interface corresponding to a predetermined antenna then being connected to all the output interfaces in order to transmit the electrical signal from the predetermined antenna to all the channels reception, the equipment being suitable for carrying out a process for calibrating the reception channels when the switching device is in the second mode of operation,

and in that the method comprises the steps of:

- switch the switching device to the second mode of operation,

- capture an electrical signal at the output of each reception channel,

- determining physical parameters associated with said electrical signals,

- configure each reception channel according to the physical parameters associated with the electrical signals determined at the output of the reception channels,

- Toggle the switching device in the first mode of operation.

6. Computer program, characterized in that it comprises instructions for implementing, by a processor (601) of equipment comprising an antenna array, a method according to the preceding claim, when the program of computer is run by the processor.

7. Recording medium on which is stored the computer program according to the preceding claim.