Abstract: A transponder, able to equip a cooperative target facing a Doppler radar, includes at least one receiving antenna able to receive a signal transmitted by said radar and a transmitting antenna able to retransmit a signal. The signal received by the receiving antenna is amplitude-modulated before being retransmitted by the transmitting antenna to produce a variation of the radar cross-section of the target, the variation triggering a frequency shift between the signal transmitted and the signal received by the radar comparable to a Doppler echo. The transponder applies notably to the field of radars, more particularly for collaborative systems also operating at low velocity or nil velocity. It applies for example to assisted take-off, landing and deck-landing of drones, in particular rotary-wing drones, as well as manned helicopters.

Abstract: An input signal amplification system comprises at least two different means of amplifying input signals in order to obtain amplified signals. It also comprises at least one means of summing amplified signals, and dynamic means of activating or deactivating one or more of the amplifying means based on input signals.

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: An active and passive detection device is provided with a low probability of interception having a fixed antenna structure, transmission means and reception means. The antenna structure is formed by a plurality of radiating elements grouped into identical subnetworks and comprises at least one transmission subnetwork and at least three reception subnetworks. The transmission means are capable of generating an unfocused continuous waveform having low peak power in one plane and of transmitting said waveform. The reception means are capable of detecting the targets following the formation of a plurality of directional beams on the basis of the signals received on the reception subnetworks. The reception means are likewise capable of implementing the interception of radar signals from other radar sources using cross correlation processing between the signals received on at least three reception subnetworks.

Abstract: A radar includes an antennal structure, with means for transmitting an impulse signal in a band centered on F1 according to a repetition period centered on a recurrence period Tr1 and pulse width T1, with means for receiving signals by the antenna in frequency band ?F, with a unit for processing the signals received on a set of N distance bins. The signals received are transmitted by another radar in a frequency band centered on F2 where F2?F1??F, according to a repetition period centered on a period Tr2 and pulse width T2. The signals transmitted by the two radars are asynchronous. The method comprises: slaving frequency F1 to frequency F2, by measuring the power received integrated over the N distance bins and over several recurrences, determination of period Tr2 and T2 and slaving the period centered on Tr1 to a period centered on Tr2 with Tr1=k*Tr2.

Abstract: A radar attached laterally to airplane fuselage to detect obstacles on a collision course with a portion of the airplane facing the radar, comprises an emission antennal channel and reception antennal channels in the same plane, the form of the wave and field of angular coverage of the radar depending on the velocity of the airplane, the processing means comprising the steps: Establishing in the radar coordinate system a first distance/Doppler map allowing echoes to be separated into distance and Doppler resolution cells in a reception antennal channels; Establishing a second distance/Doppler map of smaller size by selecting a subset of distance/Doppler resolution cells corresponding to the possible positions of targets liable to collide with the wing of the airplane; Establishing new distance/Doppler maps by forming beams computationally from the subsets of distance resolution cells retained for each reception antennal channel; and Temporal integration, in each beam, of successive distance/Doppler maps.

Abstract: 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.

Abstract: A device for detecting electromagnetic signals comprising an array receive antenna having N radiating elements and M receive channels downstream of the receive antenna, M less than N, the pointing directions of the antenna, equal to the radiating elements, obtained by adaptive beamforming and regularly spaced apart, comprises: switching the M receive channels onto the radiating elements in successive sequence cycles, M radiating elements connected to the receive channels with each sequence, the same radiating element, being the reference element, connected to the receive channels for all sequences, one cycle completed when all radiating elements are connected to one of the receive channels; for each sequence, estimating two-by-two spatial correlations of the signal received on the reference channel and the signals received on the other M-1 receive channels, then estimating the spatial power spectral density in N incoming directions based on a coherent sum of N correlation terms obtained.

Abstract: An input signal amplification system comprises at least two different means of amplifying input signals in order to obtain amplified signals. It also comprises at least one means of summing amplified signals, and dynamic means of activating or deactivating one or more of the amplifying means based on input signals.

Abstract: A device for detecting and locating moving objects that are equipped with at least one radar comprises a radar function comprising an antenna disposed on a revolving structure and a radar emissions detector function comprising an antennal part, and is characterized in that the antennal part of the radar emissions detector function is placed on said revolving structure.

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: An active and passive detection device is provided with a low probability of interception having a fixed antenna structure, transmission means and reception means. The antenna structure is formed by a plurality of radiating elements grouped into identical subnetworks and comprises at least one transmission subnetwork and at least three reception subnetworks. The transmission means are capable of generating an unfocused continuous waveform having low peak power in one plane and of transmitting said waveform. The reception means are capable of detecting the targets following the formation of a plurality of directional beams on the basis of the signals received on the reception subnetworks. The reception means are likewise capable of implementing the interception of radar signals from other radar sources using cross correlation processing between the signals received on at least three reception subnetworks.

Abstract: The invention relates to a printed circuit for high-frequency signals, and more particularly to interconnect means between transmission lines situated on different faces of the printed circuit. According to the invention, in the vicinity of the interconnect means, the transmission lines each extend in a main direction. The interconnect means comprise two vias each extending along an axis. In a plane containing the main direction of a first of the transmission lines and perpendicular to the face bearing the first transmission line, an orthogonal fix is formed whose abscissa is borne by the main direction of the first transmission line. The abscissae of the axes of the vias or of their projection on the plane, perpendicularly to the plane, are separate.

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 device is provided for use of an antennal base formed of two antennas which pick up the emissions present and produce two radioelectric signals S1 and S2. These two signals are used to produce at least one intermediate-frequency signal Fl by demodulation of one of the two signals by the other (autotransposition). The demodulation is carried out by firstly transposing one of the signals, S1 for example, around a given frequency F1, the signal S2 being preserved around its initial central frequency F0. Thus, whatever the central frequency F0 of the emission picked up by the antennas, the demodulation produces a signal of central frequency F1, thereafter demodulated into a given intermediate frequency Fl by a local oscillator of constant frequency F2=F1+Fl. The device is applied to the production of a device for detecting emissions and for characterizing the emissions picked up.

Abstract: The present invention relates to a system and a method for assisting in the decking of an aircraft on a platform, more particularly on a mobile platform comprising a decking surface, said aircraft comprising a signal transmitter, the system comprising means for determining flight commands to be executed by the aircraft, said means being at least fed by locating means of the aircraft and by means of predicting movements of the platform, the locating means comprising at least two passive sensors, spaced apart, fixed in proximity to the decking surface and able to receive the signals transmitted by the aircraft. The invention applies notably to the decking of rotary wing craft and autonomous aircraft on ships.

Abstract: A transponder, able to equip a cooperative target facing a Doppler radar, includes at least one receiving antenna able to receive a signal transmitted by said radar and a transmitting antenna able to retransmit a signal. The signal received by the receiving antenna is amplitude-modulated before being retransmitted by the transmitting antenna to produce a variation of the radar cross-section of the target, the variation triggering a frequency shift between the signal transmitted and the signal received by the radar comparable to a Doppler echo. The transponder applies notably to the field of radars, more particularly for collaborative systems also operating at low velocity or nil velocity. It applies for example to assisted take-off, landing and deck-landing of drones, in particular rotary-wing drones, as well as manned helicopters.

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 and a system for assisting in the landing or the decking of a light aircraft, the method being implemented by a system comprising a device on the ground for locating the aircraft, the aircraft having an onboard signal sender, the method comprising at least the following steps: the locating device on the ground uses signals sent by the sender to determine the position and/or movement of the aircraft; said device transmits the previously determined aircraft position and/or movement data to the aircraft; display means show at least some of said data made accessible to the pilot of the aircraft. The invention applies in particular to the field of civil light aeronautics, notably for facilitating the landing of pleasure aeroplanes, small transport aeroplanes and helicopters.

Abstract: A radar includes an antennal structure, with means for transmitting an impulse signal in a band centered on F1 according to a repetition period centered on a recurrence period Tr1 and pulse width T1, with means for receiving signals by the antenna in frequency band ?F, with a unit for processing the signals received on a set of N distance bins. The signals received are transmitted by another radar in a frequency band centered on F2 where F2?F1??F, according to a repetition period centered on a period Tr2 and pulse width T2. The signals transmitted by the two radars are asynchronous. The method comprises: slaving frequency F1 to frequency F2, by measuring the power received integrated over the N distance bins and over several recurrences, determination of period Tr2 and T2 and slaving the period centered on Tr1 to a period centered on Tr2 with Tr1=k*Tr2.