METHOD FOR INITIALIZING CARTESIAN TRACKS BASED ON BISTATIC
MEASUREMENTS PERFORMED BY ONE OR MORE RECEIVERS OF A
MULTISTATS RADAR SYSTEM
The invention relates to the general field of tracking in the context of
multistatic radars. It relates more particularly to the multi-target tracking
performed from passive multistatic systems.
5 There are a certain number of difficulties in operating a passive radar
system comprising a plurality of transmitters and/or receivers. In effect, each
transmitter-receiver pair constitutes a bistatic base from which it is possible to
perform, in different simple and known manners, the bistatic detection and
tracking of objects moving in the space covered by that base.
10 However, when the aim is to know the overall aerial situation of the
area covered by the radar system, it is necessary to jointly analyse the
information delivered by the different bistatic bases, generally analysed in the
form of individual tracks, so as to merge this information to construct global
tracks or merged tracks.
15 A joint analysis of the information produced by the different bistatic
bases consists in practice in fomriing and maintaining global Cartesian tracks
by associating the detection information, the bistatic blips, produced by the
different bistatic bases forming the detection system concerned, to form and
maintain Cartesian tracks.
20 The French patent application document filed by the applicant on
01/09/2009, under the number 0904144, describes a method that allows for
such a joint analysis. This method is illustrated by Figure 1. The method
described makes it possible to form Cartesian tracks from bistatic blips
produced by distinct bistatic bases, in the context of a detection system
25 comprising a number of receivers, two bistatic bases then being able to be
formed by the same receiver or by different receivers.
As Figure 1 illustrates and as the text of the abovementioned patent
application mentions, the formation and maintenance of these Cartesian
30 tracks naturally involves one or more initialization steps. Various known
methods can be used to perform the initialization of Cartesian tracks from

^ 31
CLAIMS
1. Method (22) for producing the association of bistatic blips
corresponding to one and the same target detected by a multistatic radar
system comprising a plurality of transmitters and receivers remote from
one another, one pair (transmitter, receiver) forming a bistatic base of the
5 system, each bistatic blip Pi corresponding to the echo originating from
the signal transmitted by a transmitter Txj and received by a receiver Ek,
each bistatic blip Pj being characterized by the transmitter Txj having
transmitted the signal of which it is the echo, characterized in that, the
bistatic blips formed being associated with the different transmitters of
10 the system to form a set of pairs (blip, transmitter), it comprises:
- a first module (31) for forming triplets of pairs (Pi, Txj), these triplets
combining pairs (blip, transmitter) which exhibit a distance and speed
compatibility;
- a second module (32) for forming n-uplets of pairs (Pi, Txj), these n-
15 uplets combining triplets formed in the preceding step satisfying given
combination criteria which characterize the likelihood of the attribution of
the different triplets to one and the same target;
The duly constituted n-uplets forming packets of blips (35) which
define one and the same target.
20
2. Method according to Claim 1, characterized in that the first step (31)
of forming triplets of pairs (blip, transmitter) is an iterative step which
considers, on each iteration, three pairs (blip, transmitter), a first pair (Pi,
Txi), a second pair (P2, TX2) and a third pair (Pref, Txref) taken as a
25 reference pair and which applies to them an association operation which
tests the possibility of associating the first pair (Pi, Txi) and the second
pair (P2, TX2) to the reference pair (Pref, Txref), a pair (blip, transmitter)
being able to be associated with the reference pair if the characteristics
of the target corresponding to the blip considered are compatible with the
30 characteristics of the target corresponding to the blip forming the
reference pair; three pairs (Pref, Txref), (Pi, Txi) and (P2, TX2), for which
the association test is successful, fonning a triplet of pairs (47).