Abstract: The invention relates to a radar system comprising: a frequency synthesizer, configured to generate a modulated local signal (Sf0+?f0); at least one frequency multiplier, configured to supply an intermediate-frequency local signal (Sf_inter+?f_inter) to each emission channel (8) and to each reception channel, the intermediate-frequency local signal (Sf_inter+?f_inter) being a fractional multiple of the modulated local signal (Sf0+?f0); a plurality of emission frequency transposition components, the emission frequency transposition components being synchronized with one another by the modulated local wave (Sf0+?f0); a plurality of reception frequency transposition components, the reception frequency transposition components being synchronized with one another by the modulated local signal (Sf0+?f0), the reception channels being configured to demodulate the intermediate-frequency reception signal (Sf_inter_Rx+?f_inter_Rx) using the intermediate-frequency local signal (Sf_inter+?f_inter).

Abstract: A Doppler radar with ambiguous electronic scanning, using an active antenna comprising an array of elementary transmission antennas and an array of elementary reception antennas with the same angular opening. The arrays have the same radiation plane. The transmission array is ambiguous with a number of ambiguous lobes within said angular opening of said elementary antennas greater than or equal to 2. The reception array comprises at least one ambiguous lobe within said angular opening. The arrays are arranged so that the product of the transmission and reception radiating patterns only produces a single main beam within the field defined by said angular opening. The coverage of said angular field by said radar obtainable by: forming at the transmission antenna radiating patterns that are focused within a field limited to the transmission ambiguity field; simultaneously forming several reception radiating patterns focused at reception in the ambiguous transmission directions.

Abstract: A method for processing coherent MIMO radar processing DDMA waveforms includes: generating waveforms on transmitters, the waveforms, modulo the pulse repetition frequency, being identical from one transmitter to the next, to within a phase ramp specific to each transmit path; generating, for at least one receiver, a Range-Doppler representation of echoes of transmitted waveforms, where, for each receiver, echoes of a transmitter occupy at least one frequency cell in the Doppler spectrum, each signal band specific to a transmitter, placement of the signal bands in the Doppler spectrum being determined by phase ramp applied to each transmitter, the waveforms generated to leave a portion of Doppler spectrum between two signal bands unoccupied; identifying the transmitter corresponding to each signal band, due to Range-Doppler representation of echoes of transmitted waveforms. The method is suitable for the millimetre band, automotive or aircraft radar, for detection of target relative to the carrier.

Abstract: A method for confusing the electronic signature of a signal transmitted by a radar, includes the generation by the radar of at least one pulse, wherein the method comprises a step of modulation, in the pulse, of the polarization of the transmitted signal, according to two orthogonal or opposite polarizations, the modulation of the polarization being performed according to a predetermined modulation code.

Abstract: An imaging method using a doppler radar wherein the pointing direction in transmission (dei) is modified from recurrence to recurrence; each detection block of duration T comprises a periodic repetition of a number C of pointing cycles, each of these cycles comprising a number P of recurrences, the set of these P recurrences covering the De pointing directions (dei) of the set; the order of the pointings is modified in a pseudo-random manner from pointing cycle to pointing cycle during a same detection block so as to create an irregular time interval between two pointings in a same direction; at least one beam is formed in reception on each recurrence in a direction included in the transmission-focused angular domain in the pointing direction corresponding to the recurrence.

Abstract: Method and device for radar transmission and reception by dynamic change of polarization notably for the implementation of interleaved radar modes are provided.

Abstract: A method and a device for measuring altitude of an aircraft relative to a point on the ground, said aircraft carrying a radar system comprising a directional antenna to transmit a radio frequency signal along a aiming axis, including. controlling the transmission of a radiofrequency signal along the axis, calculating received powers as a function of radial distance on a sum channel and an elevation deviation channel, calculating tilt angular deviation values, determining an estimator of the radial distance of the aircraft relative to the point on the ground intercepted by the aiming axis as a function of at least one zero crossing of the angular deviation measurement in a selected area of the angular deviation measurement curve, calculating an aircraft altitude relative to said point on the ground as a function of the estimator of the radial distance and the elevation angle of the aiming axis.

Abstract: A radar imaging method using an active antenna comprising N transmission channels and M reception channels, transmitting in bursts of pointing cycles, is disclosed. The antenna covers a given angular range during a detection time unit of duration T, said time unit corresponds to a burst in which the N transmission channels are focused successively in a number De of pointing directions (di) such that: the pointing direction on transmission (di) is modified from recurrence to recurrence; each time unit of duration T comprising a periodic repetition of a number C of identical pointing cycles, each of these cycles comprising a number P of recurrences, the set of these P recurrences covers the De pointing directions (di); at least one beam is formed in reception on each recurrence in a direction included in the angular range focused on transmission in the pointing direction corresponding to said recurrence.

Abstract: An active antenna radar able to produce an image with high angular resolution over a wide angular coverage, the antenna includes a number N of transmission channels and a number M of reception channels, each transmission channel and reception channel comprising an elementary antenna: each elementary antenna comprises a lens or a reflector associated with an array of elementary sources, the sources being configured to illuminate the lens or the reflector and at least the apertures being substantially arranged in the focal plane of the lens or centred around the focal point of the reflector; each elementary transmission or reception source being able to form or receive, respectively, a beam focused in a given direction, the directions being different from one transmission or reception source to another of one and the same elementary antenna; each elementary transmission or reception source being connected to a power amplifier or to a low-noise amplifier, respectively, and to switching means allowing the source

Abstract: A proximity radar method for a rotary-wing aircraft includes a sequence of phases T(k) of steps. In a first phase T(1), the electronic computer of the radar system computes unambiguous synthetic patterns on the basis of a first activated interferometric pattern M(1) of N unitary radiating groups. In the following phases T(k) of steps, executed successively in increasing order of k, the electronic computer computes synthetic patterns on the basis of interferometric patterns M(k) of rank k, wherein the N unitary radiating groups of a series deviate simultaneously in terms of azimuth and in terms of elevation as k increases, and establishes maps of rank k of the surroundings in terms of azimuth distance/direction and/or elevation distance/direction cells wherein the detected obstacle ambiguities, associated with the network lobes, are removed by virtue of the map(s) provided in the preceding phase or phases.

Abstract: The invention relates to a MIMO imaging radar system. The system comprises transmission channels (Ve1, VeM), reception channels (Vr1, VrN), and co-located radiating elements (ERe1, EReM, ERr1, ERrN) forming a two-dimensional antenna array. Each radiating element (ERe1, EReM, ERr1, ERrN) has a predefined instantaneous field of coverage. Each radiating element is formed by a plurality of p radiating sub-elements (SeElt1, SsEltp) distributed in at least one of the two dimensions of the antenna array. The radar comprises a plurality of electronic steering modules (MDe1, . . . , MDrN). Each electronic steering module is connected to one radiating element. Each steering module is configured to apply a steering command (Cmd) between all the radiating sub-elements (SeElt1, SsEltp) of a given radiating element. The steering command (Cmd) is identical from one radiating element to the next, so as to move the field of coverage of each radiating element in the same direction.

Abstract: The invention relates to a method for determining an angle of arrival of a received radioelectric signal implemented by a receiving antenna system including either one rotating antenna having at least two receiving channels, or two rotating antennas with a same speed each having a receiving channel, and having different antenna diagrams. The method includes calculating and storing a series of ambiguous angle error measurement values obtained from receiving amplitude values of a radioelectric signal coming from an emitting source on said first and second receiving channels, calculating a convolution function on said angular range tween said series of ambiguous angle error measurement values and a series of theoretical angle error measurement values of said receiving channels previously calculated and stored, and determining an angle of arrival of said received radioelectric signal as a function of an estimate of a maximum of said calculated convolution function.

Abstract: The method includes a step of forming, with a radar, a number N of beams of equal angular width that irradiate a runway and a portion of the surroundings of the runway; a step of dividing the zone irradiated by the beams into distance-angle boxes, the beams delineating the boxes anglewise; a step of taking measurements of backscattered power received from distance-angle boxes, the measurements being carried out for a set of pairs of boxes, a pair being composed of two boxes of same distance one of which, called the right box, crosses the right edge (3D) of the runway, and the other of which, called the left box, crosses the left edge (3G); a step of computing, for each pair, the difference in backscattered power between the right box and the left box, the aircraft being aligned with the axis when the difference is zero for at least two pairs of distance-angle boxes.

Abstract: A method for processing coherent MIMO radar processing DDMA waveforms and includes NTX transmitters and NRX receivers, comprising the steps of a) generating waveforms on at most NTX transmitters, the waveforms, modulo the pulse repetition frequency Fr, being identical from one transmitter to the next, to within a phase ramp specific to each transmit path; b) generating, for at least one receiver, a Range-Doppler representation of the echoes of the transmitted waveforms, where, for each receiver, the echoes of a transmitter over a plurality of range cells occupy at least one frequency cell in the Doppler spectrum, called signal band, each signal band being specific to one of the transmitters, the placement of the signal bands in the Doppler spectrum being determined according to the phase ramp applied to each transmitter, the waveforms being generated so as to leave a portion of the Doppler spectrum between two signal bands unoccupied; c) identifying the transmitter corresponding to each signal band, on the ba

Abstract: A method for jamming airborne SAR radar implemented by a jamming device includes at least two cooperating units surrounding an area on the ground to be protected, at least two units providing a radar-detection function and at least one unit providing a radar-jamming function, each unit being interlinked by a two-way data link and being synchronized by a common clock, the method comprises a step of identifying the signals received and whether the received signals correspond to SAR signals; a step of characterizing the received SAR signal over a short duration; a step of computing a filter adapted to the signal; a step of carrying out pulse compression of the signal; a step of iteratively periodically characterizing the signal over a long duration; a step of computing the jamming signals to be transmitted; a step of transmitting the jamming signals.

Abstract: Method and device for radar transmission and reception by dynamic change of polarization notably for the implementation of interleaved radar modes are provided.

Abstract: A method including providing a replica of a signal emitted by an on-board radar, receiving by a radar detector a signal, the received signal being the sum of a first signal depending on the signal emitted by the on-board radar and a second signal independent of the signal emitted by the on-board radar, the first signal being able to be represented by a linear combination of elementary signals each having an amplitude coefficient and a delay relative to the signal emitted by the on-board radar, processing the received signal, determining the amplitude coefficients and the delays of the elementary signals of the first signal relative to the signal emitted by the on-board radar, from the provided replica and the processed received signal, and eliminating, in the processed received signal, the first signal to obtain the second signal, from the provided replica.

Abstract: A method comprises at least: a first radar processing for locating and estimating the trajectory of a target on the basis of measurements of radial distances, of Doppler frequency and of angle of azimuth and of elevation of the target arising from a radar signal emitted towards the target; a second radar processing of location and of trajectory of the target along a vertical axis, by applying the principle of the inverse synthetic antenna; the disparity between the given trajectory and the trajectory estimated by the first processing, projected on a horizontal plane, and the disparity between the given trajectory and the trajectory estimated by the second processing according to the vertical axis being used to control the direction of displacement of the target.

Abstract: A proximity radar method for a rotary-wing aircraft includes a sequence of phases T(k) of steps. In a first phase T(1), the electronic computer of the radar system computes unambiguous synthetic patterns on the basis of a first activated interferometric pattern M(1) of N unitary radiating groups. In the following phases T(k) of steps, executed successively in increasing order of k, the electronic computer computes synthetic patterns on the basis of interferometric patterns M(k) of rank k, wherein the N unitary radiating groups of a series deviate simultaneously in terms of azimuth and in terms of elevation as k increases, and establishes maps of rank k of the surroundings in terms of azimuth distance/direction and/or elevation distance/direction cells wherein the detected obstacle ambiguities, associated with the network lobes, are removed by virtue of the map(s) provided in the preceding phase or phases.

Abstract: The method includes a step of forming, with a radar, a number N of beams of equal angular width that irradiate a runway and a portion of the surroundings of the runway; a step of dividing the zone irradiated by the beams into distance-angle boxes, the beams delineating the boxes anglewise; a step of taking measurements of backscattered power received from distance-angle boxes, the measurements being carried out for a set of pairs of boxes, a pair being composed of two boxes of same distance one of which, called the right box, crosses the right edge (3D) of the runway, and the other of which, called the left box, crosses the left edge (3G); a step of computing, for each pair, the difference in backscattered power between the right box and the left box, the aircraft being aligned with the axis when the difference is zero for at least two pairs of distance-angle boxes.