Thomson-csf

Thales

Philippe Lacomme

Pascal Cornic

Patrick Le Bihan

Yves Audic

The present invention relates to system for detecting obstacles () on the ground () onboard a carrier (). The detection system comprises at least two continuous-wave radars (). The radars () are linked to a system () for utilizing the detection data arising from the radars (). The detection system performs localization of an obstacle (): along a radial axis () between a radar () and the obstacle (), by calculating the distance between the radar () and the obstacle (); along a vertical axis () with respect to a radar (), by calculating the elevation of the obstacle () using monopulse deviation-measurement processing. The detection system performs localization of an obstacles along a horizontal axis () transverse with respect to a sighting axis () of a radar (), by calculating the azimuthal position of the obstacle (). The invention applies notably in respect of the detection of obstacles on the ground so as to avoid any collision between a taxiing aircraft and these obstacles.

Obstacle detection system notably for an anticollision system

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.

Method and device for frequency-modulated continuous-wave radar

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.

Device for the reduction of noise in a radar receiver

The invention relates to a process for adapting the post integration in a switched pulse repetition frequency radar and a circuit implementing this process. For that, the post integration of the detected signals is effected as a function of the signal received from the Doppler filter. For that, switches are used controlled by comparator circuits. The invention is useful in frequency ambiguous coherent Doppler radars using recurrence frequency switching by blocks.

Process for adapting the post integration in a switched pulse repetition

In order to determine the angular offset of the direction of a target tracked by a monopulse radar from the bore-sight axis of the radar antenna, sum and difference vectors .SIGMA. and .DELTA. represented by intermediate-frequency signals derived from incoming echo pulses are algebraically combined to form two ancillary vectors .gamma.=.SIGMA.+jp.DELTA. and .epsilon.=.SIGMA.+jq.DELTA. where p and q are two mutually different real coefficients, one of which may be zero. For each recurrence of a radar-pulse transmission in a series of N such recurrences, a real component V.sub.iK and an imaginary component V.sub.jK of an angular-deviation vector V is calculated as the scalar and the vector product, respectively, of the two ancillary vectors .gamma. and .epsilon.; these components are separately integrated over the N recurrences to yield two further components W.sub.i and W.sub.j whose quotient W.sub.j /W.sub.i represents a useful angular-deviation signal.

Processing device for angular deviation measurement signals of a

The invention relates to a radar telemetry device. The device comprises a first loop for the distance tracking of a moving echo comprising a detector for the position deviation of an echo signal and a telemetry mark, means for the digital calculation of the distance of the echo, means for generating clock pulses and means for generating a reference tracking window by the adding-subtracting of clock pulses. A second analog loop connecting the output of the add-subtract counting means to the deviation detector ensures a time filtering of the reference tracking window.

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Igny, France

Philippe Lacomme