Patent application number | Description | Published |
20110187586 | RADAR DETECTION METHOD, NOTABLY FOR AIRBORNE RADARS IMPLEMENTING AN OBSTACLE DETECTION AND AVOIDANCE FUNCTION - 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 ΔF 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+θ, k being an integer and θ a duration less than Tr; demodulating the signal received by the signal emitted, the resulting signal including a first sinusoid at the frequency δFdim=(1−(θ/Tr)·ΔF and a second sinusoid at the frequency δFd=(θ/Tr)·ΔF; 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 δFd and δFdim, and performing the vector sum of these two spectral lines after resetting them into phase with respect to one another; and performing a detection by comparing the modulus of the vector sum with a predetermined threshold. | 08-04-2011 |
20110221625 | Agile-Beam Radar Notably for the Obstacle 'Sense and Avoid' Function - 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. | 09-15-2011 |
20110248881 | Radar with High Angular Accuracy, Notably for the Obstacle Sensing and Avoidance Function - 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”. | 10-13-2011 |
20120001794 | System for Response to a Signal Transmitted by a Radar and Use of this System Notably for Testing Radars, in Particular of the MTI Type - A system for response to a signal transmitted by a radar includes: a passive antenna capable of receiving and then backscattering a signal transmitted by said radar; a microwave switch connected to said antenna; at least two microwave lines each having a distinct impedance and being connected to the microwave switch; and a generator capable of generating a parametrizable control signal and sending it to the microwave switch so that it switches onto one or other of the microwave lines, so as to modulate the signal backscattered by said antenna. | 01-05-2012 |
20120081247 | RADAR WITH WIDE ANGULAR COVERAGE, NOTABLY FOR THE OBSTACLE AVOIDANCE FUNCTION ON BOARD AUTO-PILOTED AIRCRAFT - 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. | 04-05-2012 |
20120212373 | System for Measuring the Radial Speed of a Moving Body - 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. | 08-23-2012 |
20130315287 | DEVICE FOR BROADBAND RECEPTION BY AUTOTRANSPOSITION AND APPLICATION TO THE DETECTION AND CHARACTERIZATION OF RADIOELECTRIC EMISSIONS - 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 F | 11-28-2013 |
20140028486 | LOCATION SYSTEM FOR A FLYING CRAFT - 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 analysing the emitted signals received by the antennas of the reception device. | 01-30-2014 |
20140091964 | METHOD OF RADAR SURVEILLANCE AND OF RADAR SIGNAL ACQUISITION - 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 ΔF, 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≦ΔF, 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. | 04-03-2014 |
20150048965 | ACTIVE AND PASSIVE ELECTROMAGNETIC DETECTION WITH A LOW PROBABILITY OF INTERCEPTION - 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. | 02-19-2015 |
20150061928 | RADAR WITH LOW INTERCEPTION PROBABILITY - 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. | 03-05-2015 |