Abstract: 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.

Abstract: A system for measuring the radial speed of a moving body in a line of sight determined for a referential position is disclosed. The system includes an emitter assembly for emitting a signal and a referential receiver assembly dedicated to reception of the signal. The emitter assembly is disposed on a first of the elements of a group formed by the moving body and the referential position. The receiver assembly is disposed on a second of the elements of the group. The emitter assembly is able to emit a signal on at least two emission frequencies, where the emission frequencies are separated by a chosen emission frequency gap. The system also includes an analyzer configured to analyze the signal received by the receiver assembly, and to measure the reception frequency gap separating the signal reception frequencies to calculate the radial speed of the moving body according to a function of the reception frequency gap and emission frequency gap.

Abstract: A radar includes a transmitting antenna and receiving antenna formed by an array of radiant elements. Antenna beams are calculated in P directions by a BFC function. Detections of a target by secondary lobes of the beams are processed by an algorithm comparing levels received in a distance-speed resolution cell, a single detection at most not being possible for each distance-speed resolution cell. Processing means use the assumption that there may probably be more than one echo with a signal-to-noise ratio that is sufficient to be detectable, for a given resolution cell of the radar, either in speed mode or in distance mode, or, alternatively, a distance-speed depending on the processing implemented; and, if there is more than one echo detectable for each resolution cell out of the plurality of beams formed by BFC, only the echo and BFC that obtain maximum power or maximum signal-to-noise ratio are/is considered valid.

Abstract: A method for detecting targets using a mobile radar having a rotary antenna, notably small targets buried in radar clutter, without increasing the number of false detections, includes determining pre-detections during N antenna revolutions, including determining pre-detections revolution by revolution, each pre-detection being stored in a grid of cells centered on the position that the radar occupied at the start of the current revolution, each grid cell corresponding to an azimuth range and a distance range. This step also includes, at the end of each revolution, a step of shifting all the pre-detections stored in the grid during the previous revolutions by the movement undergone by the radar during the last revolution. The method also includes determining detections, a target being detected from the moment that a set of pre-detections stored in the grid has its distances to the radar which constitute a linear progression during the N antenna revolutions.

Abstract: A multifunction airborne radar device includes a plurality of transmit antenna modules and/or receive antenna modules that are fixed relative to the aircraft, placed substantially over the surface of the aircraft so as to form transmit and receive beams, enabling targets to be detected for implementing a sense-and-avoid function. The airborne radar device may also comprise processing means for tracking the detected targets and for generating information sent to an air traffic control center and/or to a control device on board the aircraft. The processing device may also receive data relating to the aircraft, enabling the antenna beams to be adjusted and the tracking calculations to be refined.

Abstract: A system and method of radar location comprises radar signal emission means, an emitted pulse of duration T1 and index i starting at instant T2(i); means receiving reflected radar signals; means determining correlation between reconstruction of an emitted pulse and signal received during the time interval between T2(i)+2*T1 and T2(i+1). The means determining a correlation can reconstruct a set, of at least one truncated pulse j of duration T3(j), less than T1, 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 T2(i)+T1 and T2(i)+T1+T3(j) and determining a second signal, based on first correlated signals j, by copying the time interval, of said correlated signal j, between T2(i)+T1+T3(j) and T2(i)+T1+T3(j+1), onto the time interval, of said second signal, between T2(i)+T1+T3(j) and T2(i)+T1+T3(j+1).

Abstract: A method includes: generating a frequency-modulated continuous signal, an emission sequence being formed of successive ramps centered on a carrier frequency; fixing a modulation band ?F and the duration Tr of a recurrence in such a way that at the range limit, a reception ramp appears shifted by at least one given frequency with respect to the corresponding emission ramp, on account of the propagation delay for the outward-return journey to a target kTr+?, k being an integer and ? a duration less than Tr; demodulating the signal received by the signal emitted, the resulting signal including a first sinusoid at the frequency ?Fdim=(1?(?/Tr)·?F and a second sinusoid at the frequency ?Fd=(?/Tr)·?F; sampling the resulting signal and performing a first fast Fourier transformation on this resulting signal over the duration of each emission ramp; detecting in the resulting spectrum the spectral lines appearing at the frequencies ?Fd and ?Fdim, and performing the vector sum of these two spectral lines after resetting

Abstract: The present invention relates to a radar device with high angular accuracy. The solution provided by the invention simultaneously combines an interferometer that is accurate but, for example, ambiguous when receiving; and a space coloring mode when transmitting. The coloring of the space consists notably in transmitting on N transmitting antennas N orthogonal signals. These signals are then separated by filtering on reception using the orthogonality properties of the transmission signals. It is, for example, possible, with two contiguous antennas in transmission associated with two orthogonal codes to produce a single-pulse type system when transmitting. The invention applies notably to the obstacle sensing and avoidance function, also called “Sense & Avoid”.

Abstract: A radar device includes an antenna having at least two linear arrays of radiating elements being orthogonal to one another, a first array being used to focus a transmission beam in a first plane and a second beam being used to focus a reception beam in a second plane, orthogonal to the first plane. The focussing of the beam is obtained in the first plane by colored emission followed by a reception beam formation by computation, and in that the focussing of the beam is obtained in the second plane using reception beam formation by computation. The colored emission is carried out by combining antenna transmission sub-arrays in such a manner as to form a sum channel and a difference on reception channel according to the monopulse technique.

Abstract: A radar being carried by an aircraft includes means for transmitting an RF wave towards a target, said wave having a double form, a first waveform being composed of at least two sinusoids of different frequencies transmitted simultaneously, the radar comprising reception circuits receiving the signals reflected by the target and analysis means performing the detection of the target on the basis of the signals received. The second waveform is of the pulse type. The transmitted waveform is dependent on the relative speed of the target with respect to the carrier and on the absolute speed of the carrier.

Abstract: A method for controlling laws of illumination of a radar antenna with adjustable gain and/or phase, suitable for sending and for receiving a radar signal, the method including obtaining a position of an obstacle located in a near field of a beam of the radar antenna according to a direction of aim of said beam, calculating the laws of illumination on sending and on receiving of said radar antenna so as to adjust the direction of the aim of the radar beam while minimizing interaction and/or effects between the beam of the radar antenna and the obstacle, and implementing the calculated laws of illumination on sending and on receiving of the radar antenna.

Abstract: A radar device includes means for emitting microwave-frequency signals; means for receiving signals reflected by a target; computation means; a plurality of antenna systems disposed around the aircraft, an antenna system comprising a set of emission antennas coupled to the emission means and a set of reception antennas coupled to the reception means, each antenna system being dedicated to the coverage of a given angular sector ?; for a given antenna system, the antenna beam on reception being formed by CBF by the computation means on the basis of the signals received by the reception antennas and the antenna beam on emission is pointed by an electronic scanning system in a number greater than or equal to two of directions inside the given angular sector ?.

Abstract: A system for measuring the radial speed of a moving body in a line of sight determined for a referential position includes an emitter assembly for emitting a signal and a referential receiver assembly dedicated to reception of said signal. The emitter assembly is disposed on a first of the elements of a group formed by the moving body and the referential position. The receiver assembly is disposed on a second of the elements of the group. The emitter assembly is able to emit a signal on at least two emission frequencies, said emission frequencies being separated by a chosen emission frequency gap. The system includes a means for analyzing the signal received by the receiver assembly, to measure the reception frequency gap separating the signal reception frequencies to calculate the radial speed of the moving body according to a function of the reception frequency gap and emission frequency gap.

Abstract: A radar includes a transmitting antenna and receiving antenna formed by an array of radiant elements. Antenna beams are calculated in P directions by a BFC function. Detections of a target by secondary lobes of the beams are processed by an algorithm comparing levels received in a distance-speed resolution cell, a single detection at most not being possible for each distance-speed resolution cell. Processing means use the assumption that there may probably be more than one echo with a signal-to-noise ratio that is sufficient to be detectable, for a given resolution cell of the radar, either in speed mode or in distance mode, or, alternatively, a distance-speed depending on the processing implemented; and, if there is more than one echo detectable for each resolution cell out of the plurality of beams formed by BFC, only the echo and BFC that obtain maximum power or maximum signal-to-noise ratio are/is considered valid.

Abstract: The present invention relates to a method of eliminating ground echoes for a meteorological radar. The ground echoes being received from a predetermined area by a radar, the radar illuminating, for a predetermined number R of transmission recurrences, the area over a number P of distance cells, the method includes a step for calculating a spatial statistical parameter of the cluttered echoes received by the radar in response to the recurrences over an analysis path for distance cells, and a step to compare the spatial variation level of the spatial statistical parameter along the analysis path, the echoes being considered to be ground echoes when the level of said variation is greater than a predetermined threshold.

Abstract: The present invention relates to a procedure for measuring distance. It applies notably in respect of short-range radars, but not exclusively. The method uses an electromagnetic wave comprising at least one emission sequence (31, 32, 33, 34, 35) of the FSK type, at least two emission frequencies (F1, F2), emitted successively towards the said target a given number p of times inside the sequence. The gap ?F between the emission frequencies (F1, F2) is substantially equal to an integer number k of times the repetition frequency (SPRF) of the cycle of frequencies, the distance measurement being obtained on the basis of the measurement of difference of phases ?? between the signals received corresponding respectively to a first frequency (F1) and to a second frequency (F2).

Abstract: The present invention relates to a radar device with high angular accuracy. The solution provided by the invention simultaneously combines an interferometer that is accurate but, for example, ambiguous when receiving; and a space colouring mode when transmitting. The colouring of the space consists notably in transmitting on N transmitting antennas N orthogonal signals. These signals are then separated by filtering on reception using the orthogonality properties of the transmission signals. It is, for example, possible, with two contiguous antennas in transmission associated with two orthogonal codes to produce a single-pulse type system when transmitting. The invention applies notably to the obstacle sensing and avoidance function, also called “Sense & Avoid”.

Abstract: A radar device includes an antenna having at least two linear arrays of radiating elements being orthogonal to one another, a first array being used to focus a transmission beam in a first plane and a second beam being used to focus a reception beam in a second plane, orthogonal to the first plane. The focussing of the beam is obtained in the first plane by coloured emission followed by a reception beam formation by computation, and in that the focussing of the beam is obtained in the second plane using reception beam formation by computation. The coloured emission is carried out by combining antenna transmission sub-arrays in such a manner as to form a sum channel and a difference on reception channel according to the monopulse technique.

Abstract: A radar being carried by an aircraft includes means for transmitting an RF wave towards a target, said wave having a double form, a first waveform being composed of at least two sinusoids of different frequencies transmitted simultaneously, the radar comprising reception circuits receiving the signals reflected by the target and analysis means performing the detection of the target on the basis of the signals received. The second waveform is of the pulse type. The transmitted waveform is dependent on the relative speed of the target with respect to the carrier and on the absolute speed of the carrier.

Abstract: A radar device includes means for emitting microwave-frequency signals; means for receiving signals reflected by a target; computation means; a plurality of antenna systems disposed around the aircraft, an antenna system comprising a set of emission antennas coupled to the emission means and a set of reception antennas coupled to the reception means, each antenna system being dedicated to the coverage of a given angular sector ?; for a given antenna system, the antenna beam on reception being formed by CBF by the computation means on the basis of the signals received by the reception antennas and the antenna beam on emission is pointed by an electronic scanning system in a number greater than or equal to two of directions inside the given angular sector ?.