Thales

Thomson-csf

Jean-Paul Artis

Pascal Cornic

Jean-Michel Quellec

Maxence Marcant

Nicolas Bon

Clémentine Costes

Gérard Debionne

Henri Sauvageot

Daniel Jahan

Georges Guillaumot

Daniel Christien

Frédéric Mesnard

Olivier Pujol

Maurice Callac

Alia Iassamen

Patrick Garrec

Stéphane Kemkemian

Thierry Dousset

Alain Becker

Francisco Melero

Myriam Chabah

Jean-François Dupire

Nicolas Raguenes

Jean-Fran&ccedil;ois Henrio

The invention relates to a method for testing the electromagnetic compatibility of a radar detector with at least one onboard pulse signal transmitter, wherein said radar detector and each onboard transmitter are part of the same platform, by means of eliminating the external echo component in the signals received by the radar detector, said method comprising a training phase allowing the detected pulses to be divided into classes, grouping together the pulses for which at least two characteristics have a common range of values, and a phase of eliminating the pulses that belong to the selected classes.

Method for testing the electromagnetic compatibility of a radar detector with at least one onboard pulse signal transmitter

The invention relates to a method for testing the electromagnetic compatibility of a radar detector with at least one onboard pulse signal transmitter, wherein said radar detector and each onboard transmitter are part of the same platform, by means of eliminating the onboard component in the signals received by said radar detector, where the onboard component corresponds to the mix of the direct component and the reflected component onboard, said method comprising a training phase allowing the detected pulses to be divided into classes, grouping together the pulses for which at least two characteristics have a common range of values, and a phase of eliminating the pulses that belong to the selected classes.

The invention relates to a method for testing the electromagnetic compatibility of a radar detector with at least one onboard pulse signal transmitter, wherein said radar detector and each onboard transmitter are part of the same platform, by means of eliminating the onboard component in the signals received by said radar detector, where the onboard component corresponds to the mix of the direct component and the reflected component onboard, said method comprising a training phase allowing the detected pulses to be divided into classes, grouping together the pulses for which at least two characteristics have a common range of values, and a phase of eliminating, the pulses that belong to the selected classes.

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.

Method for deleting a signal coming from an on-board radar

A radar and method for making a radar undetectable, comprising comprises: on a transmit antenna consisting of N individual subarrays that are non-directional in at least one plane in transmission, each being linked to a waveform generator, generating, for each of the individual subarrays, a waveform so as to make each of the individual subarrays transmit continuous or quasi-continuous signals according to a temporal and periodic pattern by using transmission patterns made up of N different subarrays and which are deduced from one another by an individual delay, on the receive antenna comprising M individual subarrays adapted to pick up the reflected signals obtained from the transmission of the N individual subarrays of the transmit antenna, performing a compression of the received signal in space and in time of the received signals.

Radar with low interception probability

A location and guidance system including a flying craft and a reception device. The flying craft includes a plurality of antennas distributed around its fuselage and emitting rearwards with rectilinear polarization, the emitted signals being specific to each antenna, the positions and the dimensions of the antennas being configured such that the body of the flying craft avoids by masking for at least one antenna the reflections of the signal emitted by this antenna off the ground or off lateral obstacles whatever the position of the flying craft. The reception device is placed substantially on a trajectory axis of the flying craft and configured to be oriented to sight the rear thereof and includes at least two single-pulse antennas operating in orthogonal planes determines a position of the flying craft by analyzing the emitted signals received by the antennas of the reception device.

Location system for a flying craft

A system and method of radar location comprises radar signal emission means, an emitted pulse of duration Tand index i starting at instant T(); means receiving reflected radar signals; means determining correlation between reconstruction of an emitted pulse and signal received during the time interval between T()+2*Tand T(i+1). The means determining a correlation can reconstruct a set, of at least one truncated pulse j of duration T(), less than T, corresponding to the final part of said emitted pulse, said truncated pulses having increasing respective durations, determining at least one first correlated signal j by correlation of said truncated pulse j and signal received during time interval between T()+Tand T()+T+T() and determining a second signal, based on first correlated signals j, by copying the time interval, of said correlated signal j, between T()+T+T() and T()+T+T(j+), onto the time interval, of said second signal, between T()+T+T() and T()+T+T(j+).

System and method of radar location

A method for processing signals of an airborne radar includes a correction of the erroneous angle of pointing of the radar beam, comprising an evaluation of the error in the pointing angle for a constant height of the aerial transporter. For a given angle of scan, the method carries out at least two series of measurements of the power of the echoes returned following the emission of radar signals, each series being associated with a given distance-bin, the measurements being dependent on the angle of pointing of the radar antenna, formulates a vertical profile of the power of the echoes returned for each series of measurements, and then on the basis of each vertical profile, measures the pointing angle corresponding to a power of the echoes returned by the ground alone, and calculates the error in the pointing angle on the basis of the measured pointing angles.

Method for processing signals of an airborne radar with correction of the error in the radar beam pointing angle and corresponding device

A method of correcting the reflectivity measurements performed by a radar such as a weather radar, a reflectivity measurement being associated with a resolution volume includes analyzing the current resolution volume to determine whether the plane representing the 0&#xb0; C. isotherm passes through it. When the plane representing the 0&#xb0; C. isotherm passes through the current resolution volume, the volume is split into two parts lying on either side of said plane, the attenuation associated with the resolution volume is determined by taking into account the contribution of each of the parts to the measured reflectivity. The reflectivity associated with the current resolution volume is corrected using the attenuation thus determined. An onboard weather radar implements the method.

Method of correcting reflectivity measurements by isotherm detection and radar implementing the method

The present invention relates to a method for predicting a trend of a meteorological phenomenon on the basis of data originating from a meteorological radar. The method includes at least the following steps: a first step of extracting gray level skeletons from images representing the data of the radar; a second step of associating characteristic data indicative of the state of the meteorological system with the gray level local extrema points; a third step of pairing each gray level skeleton of the two successive images; a fourth step of predicting future positions of the forms of the images; a fifth step of predicting trend data of the meteorological system; and a sixth step of representing the information originating from the sixth tracking step. The invention can notably be applied to the establishment of a prediction of trend of a cloud mass. The prediction of the trend of a meteorological situation may be presented to a pilot of an aircraft.

Method for predicting a trend of a meteorological phenomenon on the basis of data originating from a meteorological radar

A method of correcting reflectivity measurements performed by a radar, such as a weather radar, includes a reflectivity measurement being associated with a resolution volume. The method includes acquiring the reflectivity measurement Zcorresponding to the current resolution volume, estimating the attenuation kintroduced by the cloud droplets, said estimating being carried out by using an average vertical profile of the cloud liquid water content, estimating the attenuation kintroduced by dioxygen, estimating the attenuation kintroduced by the water vapor, determining the total specific attenuation k of the non-detectable components taking into account the attenuation k, the attenuation kand the attenuation kestimated in the preceding steps, and correcting the measured reflectivity taking into account the estimated total specific attenuation k. The method may be implemented by an onboard weather radar.

Method of correcting reflectivity measurements and radar implementing this method

The invention targets a method of processing a radar image obtained from a radar. It comprises an automatic evaluation of the altitude of the isotherm at zero degrees Celsius, called zero isotherm, using a processing of the reflectivity information (rf(px)) conveyed by pixels (px) forming all or part of the radar image.

Method of processing a radar image, obtained in particular from an airborne radar, with evaluation of the altitude of the 0&#xb0; C. isotherm

The method processes measured vertical profiles of the power of the echoes returned following a transmission of radar signals, each measured vertical profile being a function of the sweep angle of the radar beam and associated with a given pointing angle/distance box pair of the radar beam. The method generates a synthetic vertical profile of the power of the echoes returned by the ground only, and includes, for each measured vertical profile: superposition of the synthetic vertical profile on the measured vertical profile in question, for various values of the sweep angle, calculation of the error that exists between the measured vertical profile and the synthetic vertical profile, for each sweep angle value in question, and an exclusion, from the measured vertical profile, of the values for which the calculated error is less than a given threshold, in order to generate a resultant vertical profile with no ground echoes.

Method for processing measured vertical profiles of the power of the echoes returned following a transmission of radar signals

The present invention relates to a method of characterizing the convection intensity of a cloud by a meteorological radar. The reflectivity of said cloud to an electromagnetic wave being distributed in space, the distribution of the reflectivity being discretized according to a network of points (i, j, k) of the space in three dimensions, at least one profile () is defined as a normalized function of a parameter (), which is in turn a given numeric function in two dimensions (i, j) of the distribution of the reflectivity at each point of the network, said normalized function varying uniformly between a minimum constant value and a maximum constant value, the function being equal to the minimum value when the parameter is less than a low threshold (threshold min) and being equal to the maximum value when the parameter is greater than a high threshold (threshold max), the cloud being characterized as convective when the profile is equal to one of the constant values and as stratiform when it is equal to the other constant value. The invention applies notably to meteorological radars on board aeroplanes.

Method of characterizing the convection intensity of a cloud, by a meteorological radar

The present invention relates to a method for determining the angular aperture corresponding to the extent in a plane of an object seen by a radar antenna, the object being situated at a given distance from the radar antenna. Echoes are measured in directions of the plane, where &#x3b8;is a variable angle corresponding to directions of the plane and &#x394;&#x3b8; is a given angular aperture. The pairwise differences are calculated between the echo measurements taken in the directions The slope is determined at a value &#x3b8;of a function e of &#x3b8;interpolated between the calculated differences, the angular aperture which corresponds to the extent of the object at the given distance being deduced from the slope. The invention has an application in meteorological radar.

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Plouzane, France

Jean-Paul Artis