The invention relates to a method for controlling the electromagnetic compatibility of a radar sensor having at least one transmitter edge pulse signal. The invention also relates to a radar sensor and an associated platform.
A platform is a hardware entity used especially in the military field. A ship, an aircraft, a land vehicle, an earth ground station or a space station are examples of such platforms.
The platforms are equipped with radar detectors and airborne radar. radar detectors have the function of receiving and detecting the radar signals while airborne radars emit radar signals.
In some situations, the radar detector receives pulses from airborne radar.
Indeed, the study of the pulse received by a detector radar from an edge of radar shows that the received pulse, a direct component and the reflected components.
The direct component is due to the propagation of the pulse transmitted between the radar antenna and that the radar sensor, according to the shortest path. The direct component therefore arrives at the radar warning receiver delayed from the transmitted pulse, but first in relation to others that are reflected.
The reflected components are due to reflections of the transmitted pulse on all material objects reflecting the environment. Different types of objects reflectors can be distinguished according to their proximity to actors (antenna board radar antenna and the radar sensor). In the order of increasing distance, the first type corresponds to the reflective surfaces of the supporting platform in visibility of actors (for example a ship superstructures, a barrel), the second type corresponds to the earth's surface (primarily the sea or earth to a certain extent) serving continuously to the radio horizon, and the third type corresponds to the particular reflecting surfaces of finite dimension bounded in the direction of propagation,
Thus, the presence of airborne radar thus interfere with the operation of the radar warning receiver, either via the direct component and the reflected components of the first, second or third type.
It is therefore desirable that the operation of radar detectors is compatible with the airborne radar. This problem is usually called electromagnetic compatibility (EMC abbreviated with the acronym).
For this, it is known to use effective mitigation throughout the reception frequency band of the radar detector. Such attenuation is, for example, performed by a PIN diode (English Positive Intrinsic Negative) then serving switch.
However, such a mitigation involves cutting all the reception during discomfort phases, which reduces the probability of intercept radar warning on the radar signals of interest.
There is therefore a need, in the context of a platform equipped with a radar sensor and at least one emitter edge pulse signals, a method for control of electromagnetic compatibility ente the radar warning receiver and each emitter edge that is more efficient.
For this, the description discloses a method for controlling the electromagnetic compatibility of a radar sensor having at least one transmitter of edge pulse signals, the radar warning receiver and each transmitter board from the same platform by removing of the component of external echoes in signals received by the radar warning receiver, the method comprising a learning phase comprising, for each transmitter of a sub-board acquisition phase to obtain detected pulses, each pulse being characterized by characteristics, the characteristics comprising at least the date of arrival of the pulse in question and the carrier frequency of the pulse in question. The method comprises a sub-phase having the
Accordig to particular embodiments, the method comprises one or more of the following features, (s) alone or according to all technically possible combinations:

- at each sub-phase calculation, the number of characteristics is less than 5.

- the characteristics include the pulse width and the direction of arrival.
- each sub-step of calculating comprises a group of classes by using a distance criterion between two classes.
- the radar detector comprises an attenuator, elimination is implemented by use of the attenuator preventing detection of pulses belonging to the field of disposal.

- the radar detector comprises a computer, the elimination being implemented by the computer by removing the detected pulses belonging to the field of disposal.

- each transmitter edge is adapted to generate a synchronizing signal, learning and elimination phases being timed with the synchronization signal of each transmitter board.
- under-acquisition phase involves the formation and use of areas of acquisition.
- under-calculation phase is implemented twice, the distribution in the first implementation of the sub-phase calculation using raw features, the distribution in the second implementation of the sub-phase calculation using the second characteristic, the first and second characteristics and being distinct classes selected for the elimination phase being the classes selected for the first implementation of the calculation sub-stage and the selected classes in the second setting implementation of the sub-phase calculation.

pulse in question and the carrier frequency of the pulse in question, the subphase having signal acquisition from the pulses emitted by the onboard transmitter considered and each corresponding to the external echo component to obtain the detected pulses, and acquisition of pulse characteristics measurements detected. The method comprises a subphase of calculation having the distribution of the detected pulses in classes with pulses where at least two features are of a common range of values, and selecting the class having a number of pulses greater than or equal to a threshold predetermined to give the selected classes and an elimination phase comprising the construction of a field of elimination, a field of

The description also relates to also a platform equipped with a radar detector as described above.

Other features and advantages of the invention will become apparent from reading the following description of the invention embodiments, given by way of example only with reference to the drawings, which are:

- Figures 1-8 are diagrammatic representations of signals to a first case;
- Figures 9 to 16 are diagrammatic representations of signals to a second case;
- Figures 17 to 24, schematic representations of signals for a third case;
- Figure 25 is a diagrammatic representation of an exemplary own radar detector to implement a method for control of electromagnetic compatibility between receptors pulse signal and edge pulse signal transmitters, and
- Figures 26 to 32, functional schematic diagrams of an exemplary implementation of the control method in several distinct stages.

There is provided a platform comprising a plurality of pulse signals of transmitters edge 2 and at least one radar sensor 4.

Before detailing the components of the radar sensor 4, there is described the disturbing environment wherein work is brought to the radar warning receiver 4 with reference to Figures 1 to 24.
Figure 1 shows the envelope of the transmitted pulses designated ie, these pulses are recurrent.
2 shows the envelope of the received signal s by a radar detector 4 as a result of the emission of the pulse ie.
Figures 3 to 6 represent the envelopes of the four physical components forming the signal received s.

3 shows the envelope of the direct component, the direct component being designated by scd.

4 shows the envelope of the component reflected by the supporting platform elements. Such a component is called reflected component edge. The reflected component edge is designated by reference numeral CRSB.

5 shows the envelope of the component reflected by the earth's surface. Such a component is called clutter. The clutter is designated by the sign of serf reference.
6 shows the envelope of the reflected component on the outer individual items. Because of the similarity with the radar echoes, the reflected component on the outer isolated objects is designated by the sign of scre reference.
In Figure 6, for example, only two echoes are shown.

7 shows a synchronization signal of an airborne radar issued by itself. The synchronization signal is designated by the sign of SRBE reference.

In the example shown, the SRBE synchronization signal temporally overlaps the transmitted pulse ie. Therefore, a first time interval τ 1 and a second time interval τ 2 can be defined.
The leading edge of SRBE synchronization signal is ahead of a first time interval τ 1 with respect to the start time of the transmitted pulse ie.
The trailing edge of SRBE synchronizing signal is delayed by a second time interval τ 2 with respect to the end time of the transmitted pulse ie.

8 shows a signal corresponding to SRBE synchronization signal which arrives at the radar detector 4 after being propagated in a transmission cable. The incoming signal is designated by the sign of srb reference.

The transmitted signal SRB is delayed by a third time interval τ 3 relative to SRBE synchronization signal.

The fourth time interval τ 4 is defined as the time delay between the beginning of the received signal s and the leading edge of SRBE synchronization signal.

It should be noted that the difference between the fourth and third time intervals τ 4 - τ 3 corresponds to notice that the leading edge of the signal transmitted srb supply in relation to the actual discomfort, it is appropriate that this notice is sufficiently large and positive for it can be used (typically at least several hundreds of nanoseconds).

A fifth time interval τ 5 is defined as the time interval between the leading edge of SRBE synchronization signal and arrival date, the later of pulses reflected by the edge type CRSB.

A sixth time interval τ 6 corresponds to the time interval between the leading edge of SRBE synchronizing signal and the passage of serf clutter in a non-disruptive power.

It is also defined a seventh time interval τ 7 and an eighth time interval τ 8 respectively corresponding to the starting times and end times of the first echo with respect to the leading edge of the synchronization signal SRBE. The ninth and tenth time intervals τ 9 and τ 10 correspond to the same time to the second echo.

Figures 1 to 8 illustrate the case where the transmitted pulse is sufficiently short (Figure 1), there is no temporal overlap between the direct component scd (Figure 3) and the reflected component of CRSB edge (Figure 4) , so that the received signal s has two pulses at the start of induction (Figure 2).

Figures 9 to 24 illustrate the case where the conditions are such that there is this temporal overlap materialized by the hatched area. In such a case, the radar detector 4 receives the vector combination of scd direct component and the reflected component edge CRSB. Generally, the resulting envelope s is linked to the amplitude-phase relationship between the two signals. Figures 9 to16 illustrate a situation of these two signals in phase and Figure 17-24 a situation in opposition. This is only a non-limiting example because, under these amplitude-phase relations are neither known nor controlled. In fact, in some cases, the casing has one or more successive pulses. Moreover, the situation is complicated even more if several components reflected edge.

An example of radar detector 4 is shown in Figure 25.

The radar detector 4 comprises two parts: a receiver 6 wave radar and a computer 8.

The receiver 6 comprises N channels.

N is an integer greater than or equal to 2 when the receiver 6 is adapted to implement the goniometry.

According to another embodiment, the receiver 6 has a single channel.

In Figure 1, only three channels are represented: the first way, the nth channel and the N-th track. The presence of the other channels is indicated by dotted lines.

Each channel includes an antenna 10 followed by an attenuator 1 1 1 1 being the attenuator followed by a receive chain 14.

Each antenna 10 is capable of receiving a radio signal and outputting an electrical signal to the attenuator 1 1 from the received radio signal.

The set of antennas 10 allows the direction finding signals received by the antennas.

The attenuator 1 1 comprises a set of signal attenuation elements.

The presence of the attenuator 1 1 makes it possible to ensure electromagnetic compatibility.

The attenuator 1 1 comprises at least one switch 12.

Switch 12 is able to pass a signal or not.

According to a particular example, the switch 12 is controlled PIN diode bias by the blanking signal and providing an attenuation of between 40-60 dB.

According to the example of Figure 25, the attenuator 1 includes 1 / insertion devices 13 of a notch filter in series, each corresponding to the rejection of a suitable frequency range vis-à-vis the airborne radar with an attenuation of the order of 30 to 60 dB.

Each receiving chain 14 is adapted to deliver a signal so that all the receiving channels 14 is suitable for delivering in parallel N signals.

The calculator 8 is, for example, a set of digital components.

Alternatively, the computer 8 is a computer program product, such as a software.

The calculator 8 is able to implement the steps of a control method of the electromagnetic compatibility of the receiver 6 with the pulse signal edge emitters 2.

The operation of the radar sensor 4 is now described with reference to Figures 26 to 32 which show a schematic view of the control method in several distinct stages.

For this, the computer 8 is broken down into modules, this breakdown showing the different functions that the computer 8 is able to implement.

The ECU 8 includes a characterization module 15 pulses, a characterization module development and characterization of the tracks 17 and a compatibility module 22 interposed between the two modules 15 and 17.

The characterization module pulse 15 is adapted to analyze the N signals that the receiver 6 is able to deliver.

The characterization module pulse 15 is adapted to characterize each detectable incident radar pulse.

Such characterization is implemented using at least one measured quantities of the pulse.

A magnitude characteristic is also referred to in the following (hence the term pulse characterized).

In one example, the variable is the arrival of the pulse t, which is the arrival time dating the leading edge of the pulse.

According to another example, the variable is the amplitude of the pulse A.

In yet another example, the magnitude is the width of the pulse LI.

According to another embodiment, the quantity is the carrier frequency of the pulse /.

In yet another embodiment, the magnitude is the intended intra-pulse modulation IMOP (English Intentional Modulation is Drawn) and possibly unintended PIU (English Unintentional Modulation is Drawn) generally designated by the modulation intra -impulsion MOP.

According to another example, the magnitude is the direction of arrival Θ. For example, the arrival direction is characterized by the azimuth, that is to say the angle of arrival in the local horizontal plane referenced to true north. Alternatively, the direction of arrival is also characterized by the site, that is to say the angle of arrival in the local vertical plane with respect to the local horizontal.

According to another example, the magnitude is the polarization of the carrier wave pol.

According to a particular example, the characterization is implemented using a plurality of measurements of quantities of the pulse, each measurement being chosen from the preceding examples.

For the following, it is assumed that the selected values ​​are the date of arrival of the pulse t, the amplitude of the pulse A, the width of the pulse LI, the carrier frequency of the pulse / the intra-pulse modulation MOP and the arrival direction Θ.

In addition, for the rest, each pulse is designated by the sign of reference IC k . k being an integer, the index k corresponding to the k-th detected radar pulse.

For the kth pulse radar detected, these values are multiplied by an index k, where writing IC k = t k , A k , LI k , f k , MOP k , e k ).

The compatibility module 22 is suitable for implementing the control method. The method uses the pulses characterized IC k also designated by the reference character 16 corresponding to the airborne radar, to optimize the use of

1 1 and the attenuator in order to eliminate the flux IC { k } hardcore pulses corresponding to the airborne radar and transmitting a pulse stream characterized filtered LCF { k } as designated by reference numeral 23 in the development unit and characterization of 17 tracks.

For this, the compatibility module 22 includes a plurality of modules visible in Figure 27. These modules are a module 40 for storing predefined size, a module 50 for measuring date of arrival, a module 60 forming areas, a module 70 for comparing a pulse characterized with a domain, a module 80 for storing the pulses characterized recalibrated, a module 90 for calculating a module 100 for storing calculated values, a module 1 10 removing characterized and a pulse module 120 for developing blankings.

The pulse stream characterized IC { k } is processed by a development module and characterization of the tracks 17, the tracks 18 being objects synthesizing all the characteristics of the radar noticeable over time (recurrence, antenna radiation modulations various).

We will now detail with reference to Figures 27 to 32 the checkout process.

The method comprises two phases, namely a learning phase and a removal phase.

The two phases are clocked by different timing signals of airborne radar.

The learning phase is operable to acquire a precise characterization of the signals from the pulses emitted by the radar through the edge pulses characterized IC k to form areas of elimination to precisely control the elimination phase, the pulses characterized IC k being selected areas through acquisition.

The learning phase is implemented for each board radar.

The learning phase comprises three sub-steps of acquiring a first sub-stage of acquiring the edge component (mixture of the direct component scd and reflected component edge CRSB), a second sub-phase acquisition of the reflected component of serf clutter and a third sub-stage of acquiring the reflected component on external objects scre isolated.

Each of the three sub-phases comprises a first pulse acquisition step characterized IC k and a second calculating step.

Figures 28-30 respectively correspond to the three sub-phases of acquisition. In each of the figures, appear the functions used in thick lines and payload decorated with an arrow to indicate the path, shaded to those used in the early stages of acquisition and full black to those used for the second calculation steps .

For each radar edge, each first acquisition step is clocked by the synchronizing signal from the onboard radar considered sr.

Each first acquiring step comprises measuring, training and comparison.

During measurement, it is measured arrival time t m i of the leading edge of the m-th pulse of SRBT synchronizing signal of the i-th on-board radar. Such measurement is implemented by the date of arrival measurement module 50, consistent with the arrival measured by the pulse characterization module 15 located upstream in the radar sensor 4, that is ie with the same origin, time resolution and measurement accuracy.

Upon formation, there is formed a capture range DA m i specific to each sub-phase, and for this m-th pulse of SRBT synchronizing signal of the i-th on-board radar. Training is implemented by the training module of 60 areas.

When comparing the pulses characterized IC k incident are compared to the domain acquisition DA m i . The comparison is implemented by the comparison module of a pulse characterized with field 70.

If the pulse characterized IC k is contained in the DA field m i , then the pulse is stored by the storage module of pulses characterized recalibrated 80, realigned in time with respect to the arrival of the synchronization pulse of board radar just measured, that is to say in the ICR form k = (Ot k , A k , LI k , f k , MOP k , e k ) where Ot k = t k - t m i , if the pulse is not used.

To be representative quantity, the pulses characterized recalibrated ICR k correspond to a number of timing pulses up to at least M eigenvalue to the i-th edge radar and but also to each sub-phase.

28 illustrates the first sub-stage of acquiring the edge component, j = M B i a further preset value and from the predefined variables storage module 40, and the capture range DA m i = DA B mi is formed by the areas forming module 60 from, for example:

a domain general characteristics of pulses of the i-th on-board radar, CG U the area being predefined and also from the predefined quantities of storage module 40, which may include Cj class definition, G L ; being a number equal or IOR = [..., CG i a ., ...] where

-
( , fmin, i, qi> fmax, i, q tm,i + 5 tmin,i,l2' , + TFF,i ) ·

Figure 30 illustrates the third sub-acquisition phase, M t = M E i a further preset value and from the predefined variables storage module 40, and the capture range DA m i = DA E half is formed by the training module of 60 areas from:

useful edge classes C BU2ii = [..., C BU2M ^.

C avec BU2 l2 > i = [(oT min l2 > i , tiip, f , i, j 'J iiach, L, I 2 ' j )] et l 2 ', i entier allant de 1

L ' 2 i , where L' 2 i , from the calculated quantities of storage module 100 and established by the second step of calculating the first sub-acquisition phase durations T FOR i and T FE i defining a range maximum on time t mA and in which the arrival of the external echo component can be; the date of arrival of the leading edge of the m-th pulse of the i-th on-board radar t mA from the date of arrival measurement module 50.

The capture range DA E mi is calculated as follows:

( F m, i + St min, i, l 2 * i + T DE, i> + tm.i St min, i, l 2 * i + T FE, i) ·

DA E, a, ~ t

(j min,i,l2' j' fmax,i,l2' ;

All steps of acquiring first stop when the number of sync pulses for the i-th on-board radar, reaches M t a value specific to each sub-phase, the set of pulses characterized recalibrated so acquired ( ..., ICR k , ...) is used by the second step of calculating the sub-acquisition phase considered.

For the first sub-acquisition phase, the second calculating portion comprises a first allocation, a second allocation, a grouping and determination.

During the first division, the pulses characterized recalibrated ICR k of the set (..., ICR k , ...) coming from the recalibrated 80 characterized pulse storage module are divided into classes according to the five quantities OT, A, LI, f and MOP, delivering a number of im characterized ulsions recalibrated H BB5 i s l by classes raw edge

where 5: i is an integer ranging from 1 to L 5: i , L 5 i being the number of classes.

This first distribution corresponds to a histogram.

In the second distribution, characterized recalibrated ICR pulse k of the set (..., ICR k , ...) characterized from the pulse storage module recalibrated 80 are divided into classes according to the two magnitudes and OT ' , supplying a number of im characterized ulsions recalibrated Η ΒΒ2 ι 2 1 by class raw edge C BB2, u 2 i =

ifrninusi- fmax.i. .d or i is an integer ranging from 1 to L 2A , L 2 , i being the number of classes.

This second distribution corresponds to a histogram.

When grouping for each of the two distributions, classes raw edge too close are grouped.

Two classes are estimated too close if the distance between cluster centers is less than a predefined value, .delta Β5 ί and A B2 i , respectively for the first and second distributions from the storage module of predefined quantities 40, dependent on natural dispersions produced by airborne radar and radar sensor measurement dispersions 4 with respect to each variable defining the class.

When determining it is determined useful classes edge from the classes edge after grouping for each of the two distributions, a useful class is a class whose number of elements is greater than or equal to the threshold Y c i preset from the module storing predefined quantities 40.

Are obtained a first set of useful classes edge C BU5 i stored in the storage module magnitudes calculated January 00, comprising The 5 i classes remaining after combination and thresholding, edge each useful classes being defined by:

min,i,l's j' ^^max,i,l's ;) ' (^min,i,l's j' ^max,i,l's ;) ' min,i,l's ;' ^ max,i,l's ;) '

'BUS,i,Ù

where the 5 ' and an nombre entier below 1 to' 5 , and a second up classes at links C BU2 mémorisé in the module of memorización de grandeurs recalculated 1 00, comprenant L ' 2 classes restant après regroupement et seuillage, chaque class bord useful étant définie C BU2M ^. = [(St min the ^ , , OT τηίπ, ί, ί, 'J ηιαχ, ί, Ι 2 ' ι )] where the u 'is a nombre entier below 1 to L' 2 (For the record, indices and assigned numbers with a prime " '" are those after consolidation and thresholding not to be confused with those before this).

Alternatively, the number of five sizes, according to which the first allocation of classes are created, is different, in particular lower.

In another example, having only the second distribution using only the two mentioned variables is conceivable.

According to another example, elimination of classes by thresholding is made before the combination.

For the second sub-phase of acquisition of the reflected component of clutter, the second calculating portion (Figure 29) comprises a distribution and research.

During the distribution, characterized recalibrated ICR pulse k of the set (..., ICR k , ...) from the storage module characterized recalibrated pulses 80, are divided into classes according to the two magnitudes and OT ' , delivering a number

im characterized ulsions recalibrated H F2, i, r 2 i P ar classes clutter

(fmin,i,r2 i> fmax,i,r2 ;)]

where r u is an integer from 1 to R 2ii , R 2 , i being the number of classes. This distribution corresponds to a histogram.

In this case, the continuous nature of the clutter, in particular of sea clutter, in that the detector radar 4 measures a pulse width equal to the maximum value for which the radar sensor 4 is designed, and repeatedly later in time as its sensitivity allows it to detect this mess. Thus the LOI value is almost unique and OT delay classes are many and continuous.

When searching, the delay classes 5t { min i ^ i , Ot maXiiir ^ are sought. More specifically, are sought delay classes from which the numbers H F2> i> r ^. at constant frequency class (fmi n , i, r 2 l , fmax, i, r 2 l ) are less than a threshold value 0 F i predefined and from the storage module of predefined quantities 40, for r 2 i integer from 1 to R u r u integer constant when r u 'sweeps all delay classes, r ufrom 1 to R u .

It is thus obtained a set F t stored in the variables memory module calculated 100, R 2 i frequency classes (fmi n , i, r 2 l , fmax, i, r 2 l ) each associated with a class of delay (OT min ^. ^ OT max ^ ^. } ),

Or :

• r 2 i is an integer ranging from 1 to R 2 i ,

* Fi = ( ■■■ ' l {r 2 l ^' - '

F t corresponding to a clutter map expressing a presence of clutter considered inconvenient for frequency classes data according to delay classes, ie depending on distance classes data for, as for a radar, the delay multiplied by half the speed of wave propagation (Ι δθηι / με) gives the distance.

For the third sub-acquisition phase of the reflected component on the outer isolated objects, the second calculating portion (Figure 29) comprises a distribution, a grouping and determination.

During the distribution, characterized recalibrated pulses ICR k of all

(..., ICR k , ...) from the storage module of pulses characterized recalibrated

80, are divided into four classes according to the quantities OT, LI, f and Θ, delivering a

number of im characterized ulsions recalibrated EB4 U i l by gross external echoes classes

where u 4 j is an integer ranging from 1 to U 4 i , U 4 i being the number of classes. This distribution corresponds to a histogram.

When grouping, classes too close Gross external echoes are combined. Two classes are estimated too close if the distance between cluster centers is less than a predefined value otherwise, A E3> i after 40, dependent on natural dispersions produced by the onboard radar and measurement dispersions radars 4 detector relatively to each variable defining the class.

When determining are grouped external echoes classes useful from the outer echoes classes after consolidation, a useful class is a class whose number of elements is greater than or equal to the threshold Y c i predefined elsewhere and from the storage module 40 predefined sizes.

It is thus obtained a useful set of classes C EU4 i stored in the quantities calculated storage module 100 comprising U 4 ' i is the number of classes remaining after combination and thresholding, each class being defined by:

where u 4 ' i is an integer ranging from 1 to U 4 ' i .

c Inc, i corresponds to a map of the frequency of class-angle distance echoes and pulse width given distance because, like a radar, the delay multiplied by half the speed of wave propagation (Ι δθηι / με) gives the distance.

Alternatively, elimination of classes by thresholding is implemented before the combination.

The elimination phase has the function of eliminating the signals from the airborne radar implementing areas of elimination, made from elements learned by the learning phase.

The elimination phase is implemented in two different modes of action, the mode of action at the level signal and the mode of action at pulse characterized IC k .

The mode of action at the level signal is a signal attenuation by the attenuator January 1 controlled by a suitable blanking signals game.

The mode of action the pulse level is characterized by removing characterized pulses (data phase).

In the example, the elimination phase uses two different disposal areas, the first dedicated to the elimination of edge components and clutter OF BF half and a second dedicated to the elimination of external components echoes

For the same board radar, the two areas of removal are generally established in parallel unless there is no material to produce due to lack of classes at the end of the learning phase ( for example, no external echo detected OF EE neither ).

A field of elimination given is only used by a single mode of action at a time.

The two areas of elimination are implemented either by the same mode of action or each by a different mode of action.

In one particular example, the mode of action in signal is for saturating components can degrade the operation of the radar detector 4, this mode of action is rather reserved to the field of elimination OF BF neither .

Figures 31 and 32 respectively illustrate the operation modes of action to the signal level and the level of the pulse characterized elimination phase. In each of Figures 31 and 32 show the functions used in thick and payload embellished with hatched lines arrow to indicate the path.
The area dedicated to eliminating components and clutter edge OF BF half is formed by the training module of 60 areas from:
all C BU5 i L ' 5 i classes and all F; R 2 i frequency classes
(fmin, i, r 2 i max, i, r 2 i ) > each associated with a time delay class r 2ii from 1 to R 2ii , these sets from the
quantities calculated storage module 100 which has stored the learning phase, and
arrival date, the leading edge of the m-th pulse of the i-th on-board radar t m i from the date of arrival measurement module 50.
For example, the field of elimination is calculated as follows:
DEBFim i =
(tm,i + tmin,i,l's i' ^m,i + ^^max,i,l's■) ' {^min,i,l's i' ^max,i,l's -) '
' Sj ' ^ 'max, i, l' s ^) '(min, i, l' sj 'fmax, i, l' s? ) ' (^^^ tiii, L, L-L' Mof ' MAXI i ' s
[— <
with the 5 'i from 1 to L' 5 i and r 2 i ranging from 1 to ff 2 , i -
The area dedicated to eliminating external components echoes OF EE half is formed by the training module of 60 areas from:
all C EU4 i U ' i classes from the calculated quantities of storage module 100 that has been stored during the learning phase, and
arrival date, the leading edge of the m-th pulse of the i-th on-board radar t mA from the date of arrival measurement module 50.
For example, the field of elimination is calculated as follows:
ax,i,u' ) '
with u 4 i integer from 1 to U ' i .
For each radar edge, the elimination phase is clocked by the synchronizing signal from the onboard radar srôj considered.
For both modes of action, a first portion is the same laying on each pulse of the synchronization signal a measure of T arrival date mA the leading edge of the m-th pulse of the synchronizing signal of SRBT i- th board radar is performed by arrival measurement module 50, consistent with the arrival measured by the pulse characterization module 15 located upstream in the radar sensor 4, that is to -dire with the same origin, time resolution and measurement accuracy.
There is also formed an area for removing m i depending on the components to be eliminated and for this m-th pulse of the synchronizing signal SRB i of the i-th on-board radar is performed by the field forming module 60.
For the mode of action at the level signal, the first part of the elimination phase is followed, as shown in Figure 31, a specific part to the mode with the module-making blankings 120, developing a set of / blkj blanking signals (21), j being an integer ranging from 1 to / and / is an integer greater or equal to 1, adapted to reproduce, for a given board radar, one of two areas of elimination or both as selected, and for all airborne radar, all effective removal areas formed by the areas 60 forming module (first portion), taking into account the definition of the attenuator SA 1 1, which is a predefined set of data and also stored in the storage module 40 of predefined sizes.
For the mode of action characterized IC pulse level k , the first part of the elimination phase is followed, as shown in Figure 32, a specific part comprising a comparison and elimination.
When comparing, the pulses characterized IC k incident are compared to the whole areas of elimination assigned for all airborne radar, from the training module areas 60 (first part), it is the same function as that of the sub-phases of acquisition of the learning phase.
Upon removal, the pulse characterized IC k of the flow IC { k } is removed by the removal module pulses characterized January 10 if the pulse characterized IC k is contained in any field of elimination, otherwise the pulse characterized IC k is left in this feed stream supplied to the developing module and slopes characterization 1 7 is thus a filtered flow ICF { k! }.
For a given board radar, the learning phase is complete to begin the elimination phase. To take account of any changes over time, waveforms and use of an airborne radar under consideration, the learning phase is restarted periodically to obtain control of the elimination phase updated. In such a case, the elimination phase to the signal level must be stopped, otherwise the current will make the elimination pulses characterized sought, impossible or, at best, flawed.
In general, during a learning phase on a given board radar, it is necessary to stop elimination phases at the signal level for other airborne radar.
The elimination phase pulses characterized has no influence on the learning phase. A steering the elimination phase pulse characterized, wrong because undiscounted does not seem awkward because the judgment of the stage will not do better and eliminating unwanted characterized pulses is not more likely than a non wrong steering.
In the context of a platform equipped with a radar detector 4 and at least an edge pulse signal transmitter 2, the method provides better electromagnetic compatibility between the radar warning receiver 4 and each transmitter board 2 .
It should be noted that the effect is always obtained by implementation of the method only on one component, for example on the edge component, the component of clutter echoes or the external component.

WE CLAIMS

1. - A method of controlling the electromagnetic compatibility of a radar warning receiver (4) with at least one edge emitter (2) of pulse signals, the radar warning receiver (4) and each transmitter of edge (2) of the same platform, by eliminating the component of external echoes in signals received by the radar warning receiver (4), the method comprising:
- a learning phase comprising, for each transmitter board (2):
- a sub-phase acquisition to obtain detected pulses, each pulse being characterized by features, the characteristics comprising at least the date of arrival of the pulse in question and the carrier frequency of the pulse in question, under the - phase comprising:
- acquisition of signals from the pulses emitted by the on-board transmitter (2) in question and each corresponding to the component external echoes, for the detected pulses, and
- acquiring the pulses detected characteristics measurements,
- a sub-step of calculating comprising:
- the distribution of the detected pulses in classes with pulses where at least two features are of a common range of values, and
- selection of classes having a number of pulses greater than or equal to a predetermined threshold for the selected classes, and
- an elimination phase comprising:
- the construction of a field of elimination, a field of elimination being the set of pulses detected by the radar warning receiver (4) belonging to the selected class, and
- elimination in the signals received by the radar warning receiver (4) of pulses belonging to the field of disposal.
2. - Method according to claim 1, wherein during each sub-step of calculating the number of characteristics is less than 5.
3. - Method according to claim 1 or 2, wherein the characteristics include the pulse width and the direction of arrival.
4. - Process according to any one of claims 1 to 3, wherein, each sub-step of calculating comprises a group of classes by using a distance criterion between two classes.
5. - Method according to any one of claims 1 to 4, wherein the radar warning receiver (4) comprises an attenuator (1 1), the elimination is implemented by use of the attenuator (1 1) preventing detection of pulses belonging to the field of disposal.
6. - Process according to any one of claims 1 to 4, wherein the radar sensor (4) comprises a computer (8), the removal being carried out by the computer (8) by removal of the detected pulses belonging to the field of disposal.
7. - Method according to any one of claims 1 to 6, wherein each transmitter board (2) is adapted to produce a synchronizing signal, learning and elimination phases being clocked with the signal synchronizing each transmitter board (2).
8. - Process according to any one of claims 1 to 7, wherein the sub-acquisition phase involves the formation and use of domain acquisition.
9. - Radar detector (4) comprising a receiver (6) of electromagnetic waves and a computer (8), the radar warning receiver (4) being configured to implement a control method of the electromagnetic compatibility of an radar warning receiver (4) with at least one edge emitter (2) of pulse signals, the radar warning receiver (4) and each transmitter of edge (2) belonging to the same platform, by removal of the component of external echoes in the signals received by the radar warning receiver (4), the method comprising:
- a learning phase comprising, for each transmitter board (2):
- a sub-phase acquisition to obtain detected pulses, each pulse being characterized by features, the characteristics comprising at least the date of arrival of the pulse
considered and the carrier frequency of the pulse in question, the sub-stage comprising:
- acquisition of signals from the pulses emitted by the on-board transmitter (2) in question and each corresponding to the component of external echoes for the detected pulses, and
- acquiring the pulses detected characteristics measurements,
- a sub-step of calculating comprising:
- the distribution of the detected pulses in classes with pulses where at least two features are of a common range of values, and
- selection of classes having a number of pulses greater than or equal to a predetermined threshold for the selected classes, and
- an elimination phase comprising:
- the construction of a field of elimination, a field of elimination being the set of pulses detected by the radar warning receiver (4) belonging to the selected class, and
- elimination in the signals received by the radar warning receiver (4) of pulses belonging to the field of disposal.
10.- platform equipped with a radar warning receiver (4) according to claim 9.