Abstract: A method for detecting an object in a scene situated in a sector and capable of comprising one or more artifacts, includes_a step of scanning the sector at an angular velocity ??, a step of acquiring digital images of the scene at a rate f by means of a matrix detector, these images comprising pixels and covering an instantaneous field of angular width “a”.

Abstract: The subject of the invention is a method for geolocalization of one or more stationary targets from an aircraft by means of a passive optronic sensor. The sensor acquires at least one image I1 containing the target P from a position C1 of the aircraft and an image I2 containing the target P from a position C2 of the aircraft. The images I1 and I2 have an area of overlap. The overlap area has at least one target P identified which is common to the two images I1 and I2. The position of each target P is determined in each of the two images. The distance d is calculated between each target P and a point C, situated for example in the vicinity of C1 and C2, as a function of the angle ?1 between a reference direction and the line of sight of the image I1, the angle ?2 between the same reference direction and the line of sight of the image I2, of the position of each target P in the image I1 and in the image I2.

Abstract: A method for detecting an object in a scene situated in a sector and capable of comprising one or more artifacts, includes_a step of scanning the sector at an angular velocity ??, a step of acquiring digital images of the scene at a rate f by means of a matrix detector, these images comprising pixels and covering an instantaneous field of angular width “a”.

Abstract: The invention relates to a method for detecting a target in a scene comprising: a step of acquiring digital images of the scene by means of a sensor, these images comprising pixels, then, for each pixel: —a step of estimating the background of the pixel, —a step of estimating the signal-to-noise ratio of the pixel, —a decision step by thresholding this signal-to-noise ratio to determine whether the pixel is a pixel of the target. The step of estimating the background of the pixel is based on the selection, for each pixel, of a so-called neighboring area, centered around the pixel, this area satisfying a predetermined uniformity criterion and the size of this area being as close as possible to a predetermined maximum size.

Abstract: The subject of the invention is a method for geolocalization of one or more stationary targets from an aircraft by means of a passive optronic sensor. The sensor acquires at least one image I1 containing the target P from a position C1 of the aircraft and an image I2 containing the target P from a position C2 of the aircraft. The images I1 and I2 have an area of overlap. The overlap area has at least one target P identified which is common to the two images I1 and I2. The position of each target P is determined in each of the two images. The distance d is calculated between each target P and a point C, situated for example in the vicinity of C1 and C2, as a function of the angle ?1 between a reference direction and the line of sight of the image I1, the angle ?2 between the same reference direction and the line of sight of the image I2, of the position of each target P in the image I1 and in the image I2.

Abstract: Method and apparatus for instantaneous processing of the glint noise in a monopulse radar. The radar antenna receives a sum signal S and a difference signal .DELTA. whose phases vary as functions of time. Successive derivatives Q.sup.(k) of order k, are calculated as a function of time from k=0 to k=N'. Also, the scaler product Q=S.times..DELTA. of the sum signal and difference signals is calculated. Then, successive derivatives P.sup.(k) of order k are calculated as a function of time from k=0 up to k=N'. Also, the power P=.vertline.S.vertline..sup.2 of the signal received, which is equal to the square of the modulus of the sum signal S, is calculated. Next, a plurality of derived angle-error measurement operators (.epsilon..sub.k) are calculated such that a .epsilon..sub.k =Q.sup.(k) /P.sup.(k). Finally, a combined angle-error measurement operator .epsilon. is calculated such that ##EQU1## The weighting coefficients .beta..sub..kappa.

Abstract: A device for removing ambiguities in the range and speed at the output of a Doppler-type radar in which all possible sets (p.sub.1, q.sub.1) and (p.sub.2, q.sub.2) corresponding to echoes at different repetition frequencies are stored in a first memory, p.sub.1 and p.sub.2 representing the number of the range quantum from which an echo signal is received and q.sub.1 and q.sub.2 the number of the filter at the output of which an echo signal is maximum. Pairs of signals are supplied in response to a first clock signal together with radar data in a second memory to two calculating circuits which carry out tests to determine of p.sub.1 and p.sub.2 and q.sub.1 and q.sub.2 respectively come from the same target and calculate the true target distance and true Doppler frequency. If both tests are positive the true distance and frequency are stored in a memory. If either is negative the first clock signal is produced to supply a new pair to the respective calculating circuits.

Abstract: This invention relates to a method of and a device for removing range ambiguity in a pulse Doppler radar and to a radar including such a device especially for missile guidance. On tracking operation at a high pulse repetition frequency the method consists in switching the repetition frequency f.sub.R (k) for each time interval .DELTA.t, over a new value f.sub.R (k+1) obtained in a circuit from the measured ambiguous range y(k) and from the ambiguity number n(k), as estimated in a circuit from radar information supplied by the radar, in order to remove eclipsing, to maintain the ambiguity number constant and to estimate the range with a growing accuracy in the course of the tracking operation.

Abstract: The present invention relates to a process for measuring the ambiguous distance in a pulse Doppler radar of repetition frequency (f.sub.R).The device comprises means (3) for transposing the signal received R(t) by a signal of frequency p.multidot.f.sub.R, where p is a positive integer; first and second narrow band filtering means (2,5) isolating the principal line of the signal received R(t) and of the transposed signal d(t) respectively, and means (6) for measuring the phase difference (.DELTA..phi.) which exists between the two filtered signals and which is proportional to the ambiguous distance with a coefficient g.