Abstract: A compact omnidirectional antenna for dipping sonar comprises multiple elementary transmission rings formed around a longitudinal axis of the antenna and multiple hydrophones distributed around the longitudinal axis, the antenna intended to be dipped in water, the hydrophones separate from the elementary transmission rings, the hydrophones and the elementary transmission rings fixed in the antenna. The elementary transmission rings and the hydrophones are interlinked along one and the same height (H) measured along the longitudinal axis.

Abstract: A compact omnidirectional antenna for dipping sonar comprises multiple elementary transmission rings formed around a longitudinal axis of the antenna and multiple hydrophones distributed around the longitudinal axis, the antenna intended to be dipped in water, the hydrophones separate from the elementary transmission rings, the hydrophones and the elementary transmission rings fixed in the antenna. The elementary transmission rings and the hydrophones are interlinked along one and the same height (H) measured along the longitudinal axis.

Abstract: The invention relates to a synthetic sonar antenna and more particularly to the self-calibration of such an antenna. It consists in minimizing the number of sensors of the reception antenna by fixing the reduced pitch between the sensors, imposed by the precision of the self-calibration, solely at the two ends of the antenna. According to a variant, the reduced pitch is fixed at just one end of the antenna. It makes it possible to increase the precision of the self-calibration with a smaller number of sensors than in the prior art.

Abstract: The invention relates to a synthetic sonar antenna and more particularly to the self-calibration of such an antenna. It consists in minimizing the number of sensors of the reception antenna by fixing the reduced pitch between the sensors, imposed by the precision of the self-calibration, solely at the two ends of the antenna. According to a variant, the reduced pitch is fixed at just one end of the antenna. It makes it possible to increase the precision of the self-calibration with a smaller number of sensors than in the prior art.

Abstract: The invention relates to an interferometric synthetic sonar antenna. It consists in processing the signals coming from the sensors of two superimposed parallel arrays forming the reception antenna, these two arrays being offset by a half-pitch between sensors, relative to each other and parallel to themselves. In a first mode of operation, the signals of the two arrays are processed to form a single synthetic antenna having a higher resolution in bearing than that of the two synthetic antennas of the interferomatric mode. In a second mode of operation, the signals of the two arrays are processes jointly in the auxiliary transmission frequency bands, enabling the two synthetic antennas to be self-calibrated with improved precision.

Abstract: The invention is a process relating to the processing of the signals sent by passive buoys dropped from an aircraft so as to compile EGP (Energy Geographic Plot) maps. The process is split into three steps: the first makes it possible to produce an EGP map of the x,y positions of the noise sources, the second makes it possible to associate the velocities Vx,Vy with certain designated positions and the third makes it possible to eliminate the noise sources regarded as hampering the readability of the maps.

Abstract: The invention is a process relating to the processing of the signals sent by passive buoys dropped from an aircraft so as to compile EGP (Energy Geographic Plot) maps.

Abstract: The invention relates to an interferometric synthetic sonar antenna.

Abstract: The invention relates to synthetic antenna sonars. It consists, in order to correct the effects of the spurious motions of the physical antenna (202) of this sonar, in simultaneously using an autofocussing by crosscorrelation of the recurrences, a measurement of the rotation of the physical antenna with a rate gyro, and a correction of this measurement of rotation on the basis of the measurement of the angle of elevation of the reception signal as obtained with the aid of an auxiliary antenna (203) perpendicular to the physical antenna. It makes it possible to obtain synthetic antenna sonars having excellent spatial resolution.

Abstract: The invention relates to autofocusing processes for synthetic antenna sonars.It consists in using at least two frequencies having different phase centers and the positions of which vary along the physical receiving antenna from one recurrence to the next. In one embodiment, three distinct frequencies are used, one for the image and the other two for the autofocusing. In another embodiment, two distinct frequencies are used, which serve alternately for the autofocusing and for the image. In another embodiment at least three distinct frequencies are used, all of which serve in the autofocusing and the formation of the image by aperture synthesis and the transmission phase centers of which, distributed at a constant spacing along the physical receiving antenna, are displaced from one recurrence to the next according to a cyclic permutation.