Abstract: A method includes: generating a frequency-modulated continuous signal, an emission sequence being formed of successive ramps centred 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 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: 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 centre 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: An airborne radar device having a given angular coverage in elevation and in azimuth includes a transmit system, a receive system and processing means for carrying out target detection and location measurements. The transmit system includes: a transmit antenna made up of at least a first linear array of radiating elements focusing a transmit beam, said arrays being approximately parallel to one another; at least one waveform generator; means for amplifying the transmit signals produced by the waveform generator or generators; and means for controlling the transmit signals produced by the waveform generator or generators, said control means feeding each radiating element with a transmit signal. The radiating elements being controlled for simultaneously carrying out electronic scanning of the transmit beam in elevation and for coloured transmission in elevation.

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: The invention relates to a method for beam formation by calculation. For each defective active module of rank ip, the missing samples of the microwave signal a(îp) are calculated by one or more non-adaptive interpolations using the samples coming from the active modules in nominal operating mode situated in the neighborhood of the defective active modules, the beam being formed as if the interpolated samples a(îp) were the real measurements. In particular, the invention is applicable to the compensation for the effects of failures of one or more active modules distributed over an antenna of a radar with electronic scanning. The method according to the invention can notably be implemented within an airborne weather radar.

Abstract: The present invention relates to a method for characterizing an atmospheric turbulence by representative parameters measured by a radar. The emission beam of the radar carried by an aircraft scanning the zone of the turbulence, a measured parameter being the total variance of the velocity of the turbulence ?U, this total variance at a point x0 inside the turbulence is the sum of the spatial variance of the spectral moment of order 1 of the signals received by the radar Var[M1({right arrow over (x)})] and of the spatial mean of the spectral moment of order 2 of the signals received Mean[M2({right arrow over (x)})], the moments being distributed as a vector {right arrow over (x)} sweeping an atmospheric domain around the point x0. The invention applies notably in respect of meteorological radars fitted to aircraft such as airliners for example.

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: An aim of the invention is to allow the detection of turbulence in the absence of tracers. A radar is embedded aboard an aircraft (21) and implements the following steps: searching for the upper part of a convective system (1) situated outside the given zone, reflecting the electromagnetic waves; searching for divergence zone (7) inside the convective system by searching for a divergence profile; reckoning the appearance of turbulence in the given zone as a function of observable meteorological phenomena in the divergence zone (7) by applying fluid mechanics properties.

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: An aim of the invention is to allow the detection of turbulence in the absence of tracers. A radar is embedded aboard an aircraft (21) and implements the following steps: searching for the upper part of a convective system (1) situated outside the given zone, reflecting the electromagnetic waves; searching for divergence zone (7) inside the convective system by searching for a divergence profile; reckoning the appearance of turbulence in the given zone as a function of observable meteorological phenomena in the divergence zone (7) by applying fluid mechanics properties.

Abstract: The invention relates to a method for beam formation by calculation. For each defective active module of rank ip, the missing samples of the microwave signal a(îp) are calculated by one or more non-adaptive interpolations using the samples coming from the active modules in nominal operating mode situated in the neighborhood of the defective active modules, the beam being formed as if the interpolated samples a(îp) were the real measurements. In particular, the invention is applicable to the compensation for the effects of failures of one or more active modules distributed over an antenna of a radar with electronic scanning. The method according to the invention can notably be implemented within an airborne weather radar.

Abstract: In a method and device for frequency-modulated continuous-wave radar detection with removal of ambiguity between the distance and the speed, the radar sends out at least alternately two parallel and discontinuous frequency modulation ramps that are slightly offset by a frequency variation (.DELTA.F), the frequency switching from one ramp to the other at the end of a given duration (Tf), the distance from a detected target being estimated as a function of the difference in phase (.DELTA..phi.) between a received signal (S.sub.1 (t)) corresponding to the first ramp and a received signal (S.sub.2 (t)) corresponding to the second ramp, the speed of the target being obtained from the estimated distance and the ambiguity straight line associated with the target. The disclosed method and device can be applied especially to radars for automobiles.

Abstract: Disclosed is a device for the reduction of noise in a radar receiver. The noise to be reduced being governed by a 1/F.sup.k relationship and the radar carrying out an encoding of the transmission in at least two frequencies, the device comprises at least the following means: firstly, means for routing the signals received to at least two channels so that, when a target is illuminated by a transmission at the first code frequency (F.sub.1), the corresponding received signal (S.sub.1) is sampled and routed to a first channel and then, when the target is illuminated by the second code frequency (F.sub.2), the corresponding received signal (S.sub.2) is sampled and routed to a second channel; and secondly, means for the linear combination of the signal (S.sub.1) present in the first channel and the signal (S.sub.2) present in the second channel, the linear combination synthesizing a filtering of the noise.