1. Method for identifying modes of radar emission by a system for detecting radar signals, a mode being characterized by a set of parameters, the said 5 method being characterized in that it comprises at least:
- a first step (32) selecting a restricted number of candidate modes
arising from a database "(34) on the basis of the interception of an
unknown radar mode to be identified able to be characterized by a
number L of given parameters;
10 - a second step (36) performing a scoring:
o by assigning a similarity index to each of the said L parameters,
for each candidate mode, the said index being the index of
similarity between the moment of the parameter of the
candidate mode and the moment of the same parameter of the
15 unknown mode and;
o by computing a value of conflict between the said parameters taken Jpairwise;-t;omputation performed on the basis of the indices of similarity of moments of each of the said parameters;
- a third step consisting in grouping together, by successive iterations,
20 the said L parameters in such a way that, at each iteration:
o the two parameters having the lowest conflict value (Kmin(t)) are
grouped together; o the similarity indices of the moments of the other parameters
are computed for the grouping;
25 o the updating of the conflicts is performed by computing the
value of conflict between the grouping and the other
parameters; o the lowest conflict value (Kmi„(t}) is stored as well as the
similarity indices (i/tJ and i2(t)) of the two parameters grouped
30 together;
the identification of the radar mode consisting in choosing the grouping (71) of parameters that arises from the iteration (t) whose value of lowest conflict (Kmin(t)) is less than a given threshold, and in retaining first the candidate

mode whose similarity index is the largest from among the similarity indices stored up to the said iteration (t).
2. Method according to Claim 1, characterized in that it uses a database (34)
5 storing the radar modes in the forms of intervals delimited by the minimum
and maximum values of each characteristic parameter, a candidate mode being selected in the said first step by comparing the measurements of parameters of the said unknown radar mode with the said intervals, a candidate mode being retained if it comprises at least one interval containing 1 o a measurement of a parameter of the unknown radar mode.
3. Method according to Claim 2, characterized in that the parameters used to
define the said intervals in the database (34) are the emission frequency, the
pulse length and the repetition period of the pulses.
15
4. Method according to any one of the preceding claims, characterized in that
the similarity indices being of the probabilistic type, the value of the conflict K
between two parameters is given by the following equation:
B
i\(£),Pz(£) being respectively the probability of one of the two parameters 20 and the probability of the other parameter, in the mode B running through the set of candidate.modes..,,.
5. Method according to any one of Claims 1 to 3, characterized in that the
similarity indices being of the possibilistic type, the value of the conflict K
25 between two parameters is given by the following equation:
K = 1 ~ sup min(7r1(j5),7r2(S))

^(B^T^CF) being respectively the possibility of one of the two parameters and the possibility of the other parameter, in the mode B running through the set of candidate modes.
5 6. Method according to any one of Claims 1 to 3, characterized in that the similarity indices being of the credibilistic type, the value of the conflict K between two parameters is given by the following equation:
Bnc=0
m1(5),?n2(C)being respectively the credibility of one of the two parameters and the credibility of the other parameter, in the modes B and C running 10 through the set of candidate modes.
7. Method according to any one of the preceding claims, characterized in that
the similarity index assigned to a parameter, for a candidate mode, is
computed on the basis of a Jaccard index, this index being defined between
15 the set of values of the said parameter for the said unknown radar mode and the set of values of the said parameter for the said candidate mode.
8. Device for identifying radar emission modes, characterized in that it
comprises a system for receiving radar signals and processing means able to
20 implement the method according to any one of the preceding claims,
9. Radar, characterized in that it is able to implement the method according
to any one of Claims 1 to 7.

A first step (32) selects a small number of candidate modes arising from a database (34) after the interception of an unknown radar mode characterized by parameters; - a second step (36) carries out a scoring operation: o by assigning a similarity index to each of said parameters, for each candidate mode, the index being the index of similarity between the moment of the parameter of the candidate mode and the moment of the same parameter of the unknown mode; and o by calculating a conflict value between the parameters taken pairwise on the basis of the similarity indices of each of the parameters; - a third step consists in iteratively grouping together the parameters such that on each iteration: o the two parameters having the lowest conflict value are grouped together; o the similarity indices of the other parameters are calculated for the grouping; o the conflicts are updated by calculating the conflict value between the grouping and the other parameters; o the lowest conflict value is memorized along with the similarity indices of the two grouped parameters; the identification of the radar mode consisting in choosing the grouping of parameters arising from iteration (t), the lowest conflict value of which is lower than a threshold, and in retaining the candidate mode having the highest similarity index from among the similarity indices memorized up to iteration (t).