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: 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 for creating a virtual reception channel in a radar system includes an antenna possessing two physical reception channels (1r, 2r) spaced apart by a distance d in a direction x, two emission channels (1e, 2e) spaced apart by the same distance d in the same direction x and processing means, the method comprising: dynamically selecting two different waveforms, the waveforms being orthogonal to each other; generating a radar pulse of given central wavelength in each emission channel, each of the emission channels emitting one of the two different waveforms; acquiring with the reception channels echoes due to pulses emitted by the emission channels and reflected by at least one target; compressing the pulses by matched filtering of the echoes acquired by each physical reception channel, this involving correlating them with each of the waveforms generated in the emission channel; and repeating steps a) to c) while randomly changing one of the values of each of the phase codes associated with the generated

Abstract: A radar system configured to determine radar-ground distance measurements. The radar system includes transmission and reception means configured to transmit two radiofrequency signals towards the ground and to receive the signals obtained by the reflection of the two transmitted signals by the ground and computation means configured to determine the frequential representations of the transmitted signals and of the received signals and determine a frequential quantity as a function of the frequential representations.

Abstract: The invention relates to a method and a device for recording digital data representative of an operating variable of an observed system, the digital data representative of said variable being obtained in the form of samples, the method comprising a data recording over time. The method receiving successive samples representative of said observed variable, and for a current sample, for at least two observation windows of different sizes, each observation window including a number, equal to the size of said window, of successive samples received before the moment in time corresponding to the current sample, calculating an average value per observation window, calculating a difference between the current sample and each of said average values, comparing each difference, in absolute value, to a predetermined threshold value associated with said observation window, and in case of excess, triggering a recording of the current sample in a non-volatile memory.

Abstract: The invention relates to a guidance system for leading an aircraft to a reference point, characterised in that it comprises: An active beacon capable of emitting a first electromagnetic signal in a first emission cone, defined by an apex coinciding with the reference point, a first beam angle and a first axis corresponding to an emission direction; and a multi-beam radar, installed on board the aircraft, operating in reception mode and capable of performing deviation measurements on a signal received from the active beacon, the multi-beam radar comprising an antenna adapted for receiving in at least two spatially separate reception cones.

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: A method for active neutralization of the effect of the vibrations of a rotary-wing aircraft for a monostatic Doppler radar includes a first step of measuring and temporally extrapolating the vibration modes at the transmitting-receiving radar antenna, using a 3-axis vibration sensor, fixed to the antenna and near the phase centre of the antenna; then a second step of estimating the expected movements of the transmitting-receiving antenna or of the first transmitting antenna and the second receiving antenna; then a third step of compensating the expected movements of the transmission radar antenna in the transmission chain or in the reception chain of the radar transmitter, wherein the projection of the movement vector of the phase centre O on an aiming direction is calculated to determine the value of the compensation phase shift to be applied.

Abstract: The method carries out a measurement of the distance from the ground of an aircraft by undertaking the emission of waveforms making it possible to obtain, after demodulation, of the signals received in return and sampling of the demodulated signals at a frequency Féch, two signals E*0(t) and E*1(t), taking the form of two frequency ramps, of respective slopes K0 and K1, of respective passbands B0 and B1 and of respective durations TE0 and TE1, the N-point FFT spectral analysis of which is carried out. The values of the durations TE0 and TE1 as well as those of the passbands B0 and B1, are defined in such a way as to be able to determine, on the basis of the spectra of the signals E*0(t) and E*1(t), a measurement of non-ambiguous distance d1 covering the maximum distance dmax to be instrumented and an ambiguous distance d0 exhibiting the desired distance resolution. The distance d to be measured being determined by combining these two measurements.

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 device transforms an analog input signal with N components x(0), x(1) . . . x(N?1) into an output signal with N components X(0), X(1) . . . X(N?1) functions of said components x(0), x(1) . . . x(N?1), said device comprising basic addition and/or subtraction cells linked in a butterfly-type architecture to perform said functions, each basic cell comprising an operator performing a conditional division by two of the result of the addition operation or subtraction operation performed, the condition being the saturation of said operator.

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: An elementary antenna includes a planar radiating device comprising a substantially flat radiating element having a center and a plane defined by (i) a straight line passing through the center and (ii) another straight line perpendicular to the straight line and passing through the center, the radiating element comprising pairs of excitation points arranged in a quadruplet of excitation points located at a distance from the lines, comprising a first pair of excitation points arranged substantially symmetrically in relation to the straight line and a second pair of excitation points arranged substantially symmetrically in relation to the other line, the elementary antenna comprising processing to supply differential excitation signals for (i) exciting the excitation points and/or (ii) shaping signals emitted from the excitation points.

Abstract: Disclosed is a calibration device of an imaging system for a moving carrier, the imaging system including: a support panel; an antenna array comprising radiating elements positioned on the support panel; and optical sensors capable of providing images and positioned on the support panel. The calibration device includes at least one optical pattern generator, each generator being secured to the support panel.

Abstract: An elementary antenna includes a planar radiating device comprising a substantially plane radiating element and a transmit and/or receive circuit comprising at least one amplification chain of a first type and at least one amplification chain of a second type, each amplification chain of the first type being coupled to at least one excitation point of a first set of at least one excitation point of the radiating element and each amplification chain of the second type being coupled to at least one point of a second set of points, the excitation points of the first and second set being distinct and the amplification chain of the first type being different from the amplification chain of the second type so that they exhibit different amplification properties.

Abstract: The device includes at least: a set of optical and/or electromagnetic elementary sensors which are able to fly and means of command for piloting the flight of the sensors; processing means; a communication link between each sensor and the processing means; to produce an image of a given scene, the sensors fly while forming an array whose configuration is controlled by the command means, the processing means fusing the signals provided by the sensors with a view to delivering an image of the scene, the signals provided being representative of the scene.

Abstract: The modulation includes in amplifying the microwave signal phase shifted by a given angle into a first sinusoidal signal, in order to obtain a first amplified signal; and in amplifying the microwave signal phase shifted by the given angle increased by ? into a second sinusoidal signal phase shifted by ? with respect to the first signal, in order to obtain a second amplified signal phase shifted by ? with respect to the first amplified signal; the modulated microwave signal being the sum of the first amplified signal and the second amplified signal.

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 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.