Abstract: Disclosed is a method for determining a dimension of a ship, the method being implemented by an electronic system with a radar device having two receiving channels. The method includes: acquiring, for each of the two receiving channels of the radar device, a synthetic aperture radar image imaging the ship in an environment; the sum of the respective amplitudes of the pixels of the two radar images to obtain a sum image; extracting pixels from the sum image imaging the ship to obtain a mask of the ship; determining a range of phase differences between the radar signals received by each of the two receiving channels; and determining a dimension of the ship as a function of the mask of the ship and the determined phase difference range.

Abstract: A method for manufacturing a radio-direction-finding antenna array in two dimensions includes a step of designing the antenna array with the help of predetermined constraints, the designing step comprising: a step of defining a reference antenna network, a step of searching for configurations to be taken into consideration of each of the antennas forming a direction-finding antenna array, a step of quantifying the maximum level of ambiguities of each of the possible configurations with the help of a correlation function so as to associate an evaluation quantity with each of the configurations considered, a step of searching for and selecting the configuration exhibiting the lowest evaluation quantity.

Abstract: Disclosed is a method for determining a dimension of a ship, the method being implemented by an electronic system with a radar device having two receiving channels. The method includes: acquiring, for each of the two receiving channels of the radar device, a synthetic aperture radar image imaging the ship in an environment; the sum of the respective amplitudes of the pixels of the two radar images to obtain a sum image; extracting pixels from the sum image imaging the ship to obtain a mask of the ship; determining a range of phase differences between the radar signals received by each of the two receiving channels; and determining a dimension of the ship as a function of the mask of the ship and the determined phase difference range.

Abstract: A method for detecting an electromagnetic signal comprises: applying to the received electromagnetic signal a plurality of time-frequency transforms, for each time/frequency cell of a given set of cells, calculating the energy of the vector made up of the spectra over all of the antenna elements, applying the following nonlinear function T to the result of the energy calculation: if the norm of the energy is below a first predetermined threshold s, the result of the function T is zero, if the norm of the energy is above or equal to the first threshold s, the result of the function T is equal to the norm of the energy minus the value of the first threshold s, integrating, over the set of time/frequency cells, the result of the nonlinear function T, comparing the result of the integration to a second predetermined threshold, to detect the presence of the signal.

Abstract: A method for detecting an electromagnetic signal comprises: applying to the received electromagnetic signal a plurality of time-frequency transforms, for each time/frequency cell of a given set of cells, calculating the energy of the vector made up of the spectra over all of the antenna elements, applying the following nonlinear function T to the result of the energy calculation: if the norm of the energy is below a first predetermined threshold s, the result of the function T is zero, if the norm of the energy is above or equal to the first threshold s, the result of the function T is equal to the norm of the energy minus the value of the first threshold s, integrating, over the set of time/frequency cells, the result of the nonlinear function T, comparing the result of the integration to a second predetermined threshold, to detect the presence of the signal.

Abstract: A method for constructing focused radar images includes chopping the radar illumination period into p sub-periods, two successive sub-periods overlapping temporally; choosing n successive sub-periods from among the p sub-periods, and for each of the n chosen sub-periods, performing radar acquisitions to generate an image IM_0x of resolution R0; and applying an autofocus processing to each of the n images IM_0x generated; combining the n images so as to generate at least one new focused radar image IM_1x. The method is applied notably to the production of high-resolution SAR images with the help of an aircraft equipped with a radar antenna.

Abstract: The present invention relates to a method for angularly refining the antenna beam of a radar. The antenna performs M pointings along an axis, a signal being received by the antenna for each of said pointings, each of said signals being, on account of the shape of the antenna pattern, formed by the sum of signals reflected by several contributors distributed over the space scanned by the antenna beam, the method determining an estimation of the real-reflectivity vector w of N contributors by performing an inverse filtering on the vector s of the M signals received signals, said inverse filtering being established as a function of the known shape of the antenna pattern. The invention applies notably to airborne radars, and more particularly to meteorological radars.

Abstract: A method for constructing focused radar images includes chopping the radar illumination period into p sub-periods, two successive sub-periods overlapping temporally; choosing n successive sub-periods from among the p sub-periods, and for each of the n chosen sub-periods, performing radar acquisitions to generate an image IM_0x of resolution R0; and applying an autofocus processing to each of the n images IM_0x generated; combining the n images so as to generate at least one new focused radar image IM_1x. The method is applied notably to the production of high-resolution SAR images with the help of an aircraft equipped with a radar antenna.

Abstract: Detecting reflectors of an emitted electromagnetic pulse, using a received signal, by time-sampling the received signal and the emitted pulse at a same sampling frequency, each received sample corresponding to a return-trip distance for the emitted pulse between its transmitter and a possible reflector. The sampled received signal is divided by the emitted pulse sampled and temporally translated into an interval of duration equal to the emitted pulse divided into L samples, producing L results of the division. A weighted summing of the L results of the division is calculated, the sets of L weights each having a support on which the weights are not zero, every subinterval of length between L/n and L being the support for at least one set of weights and no support having a length of less than L/n, wherein the sums of the weights of a set all being equal, and n is a nonzero integer such that L/n is greater than or equal to 2.

Abstract: Detecting reflectors of an emitted electromagnetic pulse, using a received signal, by time-sampling the received signal and the emitted pulse at a same sampling frequency, each received sample corresponding to a return-trip distance for the emitted pulse between its transmitter and a possible reflector. The sampled received signal is divided by the emitted pulse sampled and temporally translated into an interval of duration equal to the emitted pulse divided into L samples, producing L results of the division. A weighted summing of the L results of the division is calculated, the sets of L weights each having a support on which the weights are not zero, every subinterval of length between L/n and L being the support for at least one set of weights and no support having a length of less than L/n, wherein the sums of the weights of a set all being equal, and n is a nonzero integer such that L/n is greater than or equal to 2.