Abstract: Method of high-resolution direction finding to an arbitrary even order, 2q (q>2), for an array comprising N narrowband antennas each receiving the contribution from P sources characterized in that the algebraic properties of a matrix of cumulants of order 2q, C2q,x(l), whose coefficients are the circular cumulants of order 2q, Cum[xi1(t), . . . , xiq(t), xiq+1(t)*, . . . , xi2q(t)*], of the observations received on each antenna, for cumulant rankings indexed by l, are utilized to define a signal subspace and a noise subspace.

Abstract: Method of multi-parameter direction finding of several sources in an array of N sensors, comprising at least the following steps: a) choosing a parameter to be determined, or parameter of interest, b) expressing the direction vector in the form of a linear relation between the parameter of interest chosen and the secondary parameters b0(?, ?0)=U0(?) ?0(?0), c) applying a MUSIC-type direction finding step by factorizing the criterion serving for the determination of the angles of incidence so as to determine at least the incidence parameter, d) on the basis of the incidence value, determining the vector representative of the secondary parameters and expressing this vector in the form of a linear relation between a chosen parameter to be determined and the other secondary parameters, e) applying a MUSIC-type direction finding step by factorizing the criterion serving in the determination of the chosen parameter, f) repeating steps d) to e) so as to determine the majority or the whole set of secondary parameters

Abstract: The invention relates to a method of localization of one or more sources, said source or sources being in motion relative to a network of sensors, the method comprising a step of separation of the sources in order to identify the direction vectors associated with the response of the sensors to a source having a given, incidence, characterized in that it comprises at least the following steps: associating the direction vectors a1m . . . aKm obtained for the mth transmitter and respectively at the instants t1 . . . tK, localizing the mth transmitter from the associated vectors a1m . . . aKm.

Abstract: A method for localizing one or more sources, the source or sources being in motion relative to a network of sensors, comprises a step for the separation of the sources in order to identify the direction vectors associated with the response of the sensors to a source at a given incidence. The method comprises the following steps of associating the direction vectors a1p(1)m . . . aKp(K)m obtained for the mth transmitter and, respectively, for the instants t1 . . . tK and for the wavelengths ?p(1) . . . , ?p(k), and localizing the mth transmitter from the components of the vectors a1p(1)m . . . aKp(K)m measured with different wavelengths.

Abstract: A method for the fourth-order, blind identification of at least two sources in a system comprising a number of sources P and a number N or reception sensors receiving the observations, said sources having different tri-spectra. The method comprises at least the following steps: a step for the fourth-order whitening of the observations received on the reception sensors in order to orthonormalize the direction vectors of the sources in the matrices of quadricovariance of the observations used; a step for the joint diagonalizing of several whitened matrices of quadricovariance in order to identify the spatial signatures of the sources. Application to a communication network. FIG. 3 to be published.

Abstract: Method of locating one or more transmitters on the basis of an array of sensors moving with respect to the transmitters comprising at least the following steps: determining the direction vectors âk corresponding to the response of the array of sensors to a source with incidence (?, ?) as a function of the incidence parameters ?, ?, and of the parameter p related to the distortion of the phases on the sensors, transforming this vector âk so as to eliminate the unknown parameter p, into a vector ?km, ??km, using the transformed vector to obtain the position of the transmitter using a maximized locating criterion.

Abstract: Process for the blind demodulation of a linear waveform source or transmitter in a system comprising one or more sources and an array of sensors and a propagation channel. The process comprises at least the following steps: the symbol period T is determined and sampled to Te such that T=ITe (I being an integer); a spatio-temporal observation z(t), the mixed sources of which are symbol trains from the transmitter, is constructed from the observations x(kTe); an ICA-type method is applied to the observation vector z(t) in order to estimate the Lc symbol trains {am-i} that are associated with the channel vectors ?z,j=?z(kj); the Lc outputs (âm,j, ?z,j) are arranged in the same order as the inputs (am-i,hz(i)) so as to obtain the propagation channel vectors ?z,j=?z(kj); and the phase ?imax associated with the outputs is determined.

Abstract: The invention relates to a method of localization of one or more sources, said source or sources being in motion relative to a network of sensors, the method comprising a step of separation of the sources in order to identify the direction vectors associated with the response of the sensors to a source having a given, incidence, characterized in that it comprises at least the following steps: associating the direction vectors a1m . . . aKm obtained for the mth transmitter and respectively at the instants t1 . . . tK, localizing the mth transmitter from the associated vectors a1m . . . aKm.

Abstract: A method for the blind identification of sources within a system having P sources and N receivers comprises at least one step for the identification of the matrix of the direction vectors of the sources from the information proper to the direction vectors ap of the sources contained redundantly in the m=2q order circular statistics of the vector of the observations received by the N receivers. Application to a communications network.

Abstract: A method for the detection of M0 sources common to several observations u(t) and v(t) within a single array of sensors, the observations having different lengths N1 and N2, comprises at least the following steps: defining a law of likelihood Vuv([M=M0]/M0) substantially equal to the chi-2 law with 2(N1?M0)(N2?M0) degrees of freedom with N1?N2, dim{u(t)}=N1×1 and dim{v(t)}=N2×1; determining a detection threshold ?M in order to obtain a low probability of false alarms and a number of degrees of freedom that takes account of the lengths N1 and N2 and of the number of sources M0; determining the presence and/or the number of the sources M0 in applying the law of likelihood and the threshold ?M. The method and device can be applied to the determining of the presence and/or the number of sources common to at least two observations having different lengths in a GSM type radiocommunications system.

Abstract: A process for locating radio sources by a two-channel high resolution radiogoniometer including a network of a specified number N of sensors. The process multiplexes the signals supplied by the N sensors on the inputs of only two receivers. Then, with the aid of a calculation device coupled to the outputs of the two receivers, the angles of arrival of the waves emitted by the sources are estimated on the basis of an estimation of the covariance matrix of the signals supplied by the two receivers.

Abstract: A method for localizing one or more sources, said source or sources being in motion relative to a network of sensors, comprises a step for the separation of the sources in order to identify the direction vectors associated with the response of the sensors to a source at a given incidence. The method comprises the following steps of associating the direction vectors a1p(1)m . . . aKp(K)m obtained for the mth transmitter and, respectively, for the instants t1 . . . tK and for the wavelengths ?p(1) . . . , ?p(k), and localizing the mth transmitter from the components of the vectors a1p(1)m . . . aKp(K)m measured with different wavelengths.

Abstract: A method for the blind identification of sources within a system having P sources and N receivers comprises at least one step for the identification of the matrix of the direction vectors of the sources from the information proper to the direction vectors ap of the sources contained redundantly in the m=2q order circular statistics of the vector of the observations received by the N receivers. Application to a communications network.

Abstract: A method for the fourth-order, blind identification of at least two sources in a system comprising a number of sources P and a number N of reception sensors receiving the observations, said sources having different tri-spectra. The method comprises at least the following steps: a step for the fourth-order whitening of the observations received on the reception sensors in order to orthonormalize the direction vectors of the sources in the matrices of quadricovariance of the observations used; a step for the joint diagonalizing of several whitened matrices of quadricovariance in order to identify the spatial signatures of the sources. Application to a communication network.

Abstract: Method and device for space-time estimation of one or more transmitters based on signals received using an antenna network. Signals received using the antenna network are separated in order to obtain signals s(t). Signals s(t) are grouped by transmitter, where the signals s(t) are from more than one transmitter, and arrival angles &thgr;mi of the multipaths pm transmitted by each transmitter are determined.

Abstract: The disclosure relates to methods and devices for the real-time localization of terrestrial transmitters belonging to a TDMA type cellular radiocommunications network. The device comprises an antenna array, a multichannel receiver and a digital processor. The method consists of the interception, from an aircraft, of radioelectric signal and the detection of these signal by the implementation of a multichannel synchronization to determine the various sources of transmission, the simultaneous computation of an elevation angle &Dgr; and an azimuth angle &thgr; to instantaneously determine the direction of arrival of the radioelectric signal from the determined transmission sources and the building of track in the geographical areas in which the transmission sources are located in order to estimate the position of the transmitters.

Abstract: The invention concerns digital signal transmission. In particular, it concerns high speed transmission using layered space-time encoding architecture adapted to all types of propagation channels.

Abstract: In a method of co-operative radio direction-finding in transmission in a system of radio direction-finding for a radiocommunications system comprising one or more transmission sources or transmitters, the transmitted signal comprises a reference sequence formed by a sequence of symbols {Sk}, the receiver comprising at least one array of several sensors coupled to a radio direction-finder. The method comprises the following steps: a) determining the reference signal or signals di(t) associated with a transmitter m from the reference symbols {Sk} and from the modulation defined by the format of the signals; b) defining the instant of arrival tk of one or more reference signals; c) from the signal x(t) received at the sensors, the instants of arrival tk and the reference signal or signals di(t) derived from the step a), determining the value or values of incidence of the signals for a given transmitter. The method can be applied to GSM or UMTS signals.

Abstract: An antenna processing method for centered or potentially non-centered cyclostationary signals, comprises at least one step in which one or more nth order estimators are obtained from r-order statistics, with r=1 to n−1, and for one or more values of r, it comprises a step for the correction of the estimator by means of r-order detected cyclic frequencies. The method can be applied to the separation of the emitter sources of the signals received by using the estimator or estimators.

Abstract: In a method of co-operative radio direction-finding in transmission in a system of radio direction-finding for a radiocommunications system comprising one or more transmission sources or transmitters, the transmitted signal comprises a reference sequence formed by a sequence of symbols {Sk}, the receiver comprising at least one array of several sensors coupled to a radio direction-finder.