Abstract: Method for estimating shifts of line images obtained by an airborne or spaceborne scanning sensor. The invention relates to a method for estimating shifts in line images of an image, referred to as a “composite image”, made up of the juxtaposition of J line images. The line images show portions of a scene on the surface (S) of a celestial body that are different and successively acquired by a row of sensitive cells of a sensor (10) on board a vehicle flying over the celestial body. The shifts in the line images are induced by sighting errors of the sensor (10) during the acquisition of the line image Lj. The lateral and/or longitudinal shift of a line image Lj relative to a line image Li, where j is different from i, is estimated according to a local model of lateral and/or longitudinal variation of the similarity between different line images.

Abstract: An attitude control actuator of a spacecraft includes a first momentum wheel driven in rotation by a motor and a second momentum wheel. Both momentum wheels are movable in rotation about an axis and are mechanically coupled by coupling means imposing between a rotation speed ?1 of the first momentum wheel and a rotation speed ?2 of the second momentum wheel a ratio R=?2/?1, negative on the one hand and continuously modifiable by the coupling means in response to a command on the other hand so as to modify the total angular momentum of the actuator while the total kinetic energy of the wheels are kept constant. In one embodiment, both momentum wheels have the same inertia and are coupled through a toroidal variable rotation speed drive, where ratio R varies between ?3 and ??. The motor drives the momentum wheels and operates as a generator for braking the momentum wheels.

Abstract: A multi-beam telecommunications satellite, intended to be placed in orbit around the earth, and adapted to relay data between terrestrial terminals and at least one ground station and to form beams on a user link between the satellite and terrestrial terminals, includes a module for forming beams on board in the satellite, a module for processing beams in the ground station, and a module for routing signals received from the ground station and/or from terrestrial terminals, signals of beams formed on board being routed towards the on-board beam forming module, and signals of ground-formed beams being routed towards the ground-formed beam processing module. A telecommunications system including the multi-beam satellite, a ground station and a beam management center adapted to divide the beams into one group of ground-formed beams and one group of beams formed on board, as well as a method for forming beams are disclosed.

Abstract: A method for stabilizing a line of sight of an imaging system on board a satellite uses windows selected within an image sensor. Variations of the line of sight can be characterized at a frequency that is greater than that of a sequential mode of image acquisition by the sensor. The stabilization method can be implemented at the same time as the full-frame acquisition of images by means of the imaging system.

Abstract: Method for estimating the movement of an observation instrument on-board a vehicle flying over a celestial body, the instrument including at least two strips with different lines of sight, each strip realizing the acquisition of successive image lines making up a composite image, parts of the composite images representing substantially a same scene of the celestial body. The estimated movement is determined by optimization of an image similarity function that associates, to a given movement hypothesis, a similarity between values of matched pixels of at least a pair of composite images. The method includes, for each movement hypothesis considered during the optimization: determining, for the at least one pair of composite images, at least one spatio-temporal transformation using the considered movement hypothesis and a geometric model of the observation instrument, and matching the pixels of the at least one pair of composite images using the at least one spatio-temporal transformation.

Abstract: The invention related to a device comprising at least three insulation modules distributed around vibration equipment. Each module comprises at least two rigid parts, at least one of said parts being an outer part fixed to the carrier structure and at least one of said parts being an inner part fixed to the equipment or the stand (3) thereof. At least one elastomer insulating plug connects an inner part and an outer part and at least one of said parts carries two longitudinal flexible abutments and two tangential flexible abutments which each have a free end facing another respectively outer or inner rigid part, said free end being at a distance from the inner part in an idle position. The invention can be applied to satellite equipment.

Abstract: A method of command of magneto-torquers of an attitude control system of a space vehicle subjected to an external magnetic field of variable direction. The magneto-torquers are configured to desaturate an angular momentum storage device by transferring angular momentum and configured to form, in cooperation with the local external magnetic field, magnetic couples in a plane orthogonal to the direction of the local external magnetic field or a local control plane. The magnetic couple to be formed in the local control plane is determined as a function of the component of a desired attitude control couple which is orthogonal to the local control plane or a locally uncontrollable component. The contribution of the locally uncontrollable component to the magnetic couple to be formed is non-zero when the locally uncontrollable component is non-zero.

Abstract: The remote communications system, intended for low-throughput data transfer between at least two users located substantially on the surface of a celestial body, includes: a plurality of transmitting/receiving surface terminals, each associated to a user, one or more geostationary element installed on board satellites placed in geostationary orbit around the celestial body, these geostationary elements being able to transmit data from and to a predefined coverage area on the surface of the celestial body with a line of sight to the geostationary satellite, and one or more signal repetition element for the signals transmitted and/or received from the geostationary elements to the surface terminals these traveling repetition elements being on board satellites moving in a traveling orbit; the same frequency band is used for communications between the surface terminals and the traveling elements and for communications between the traveling elements and the geostationary elements.

Abstract: A method and system for estimating a path difference between two paths followed by a target signal transmitted by a spacecraft or aircraft to a first receiving antenna and a second receiving antenna of a receiving base, respectively. A useful-phase difference is measured between signals corresponding to the target signal received on the first receiving antenna and second receiving antenna. The path difference is estimated on the basis of the measurements of the useful-phase difference. A calibration signal is transmitted to the receiving base and a calibration phase difference between signals corresponding to the calibration signal received on the first receiving antenna and second receiving antenna is measured. Variations are compensated in the measurements of the calibration-phase difference relative to the measurements of the useful-phase difference.

Abstract: A rolling bearing device, of the type including a central shaft and a hub (10) mobile in rotation relative to each other, the bearing including at least two rolling bearings (12, 13), one designated “lower” and the other designated “upper”, arranged between the central shaft (11) and the hub (10) in two positions spaced in the axial direction Z, these rolling bearings being fitted with inner (14, 16) and outer (15, 17) rings and with balls (18, 19), the rolling bearings being assembled back-to-back or face-to-face, a rigid preload being applied to these bearings along the axial direction Z, internal (22) and external (23) spacers being arranged between these rolling bearings, the inner (22) and outer (23) spacers have lengths adjusted to limit variations in rigid preload caused by temperature gradients from one point of the bearing to another to less than 30%, particularly thermal gradients in the radial direction.

Abstract: The invention relates to a polychromatic imaging method, using a picture-taking instrument, which is placed on board an aircraft or satellite, which enables a reduction of the size of the instrument without reducing resolution of a final obtained image. To this end, a pupil of the instrument is sized for intermediate images that are limited to a first spectral sub-band without any image information being completely transmitted by the instrument for at least one wavelength that is located beyond said first spectral sub-band. Merging the intermediate image, inputted for the first spectral sub-band, with at least one other intermediate image, inputted for another spectral sub-band, recreates a polychromatic visual rendering that is satisfactory for the final image. Said other intermediate image includes the wavelength located beyond the first sub-band.

Abstract: A device for thermal monitoring a piece of equipment, which is integrated on a craft placed in a forced vacuum environment, an outside part of the equipment projecting outside of a wall of the craft and being subjected to a solar radiation flux, includes an absorbent screen that is suitable for being placed between the outside part of the equipment and the wall of the craft, whereby this absorbent screen has—on at least one portion of its front face, designed to be placed on the side removed from the wall of the craft—an absorptivity ?SOLAR that is the largest possible in the field of solar radiation, coupled to a low emissivity ?IR in the infrared spectrum. The absorbent screen is made of a very heat-conductive material and has—on at least a portion of its rear face, suitable for being oriented toward the wall of the craft—a high emissivity ?IR in the infrared spectrum, typically greater than or equal to 0.7.

Abstract: A wing or blade in at least two sections facing each other. Each section has a longitudinal bearing structure provided with at least one sole of which the link between the sections includes at least one first link plate linking the end of the soles of the sections facing each other. A method of producing such wing or blade.

Abstract: A method of controlling the attitude of a satellite in orbit around a celestial body. The attitude of the satellite being controlled by a momentum storage device and controllable surfaces of the satellite configured to create desaturation torques in the storage device by using solar pressure. The controllable surfaces are arranged on solar panels mobile in rotation around an axis Y. At least one electric thruster configured to control the orbit of the satellite also controls the attitude of the satellite. The orientation of the electric thruster is controlled to activate the electric thruster with a thrust direction deliberately not aligned with a center of mass of the satellite to create desaturation torques in the storage device along axis Y. The controllable surfaces are controlled to create desaturation torques of the storage device in a plane orthogonal to the Y axis.

Abstract: A service admission control method in a communication network comprising at least one group of at least one node per group, the method comprising the steps: Receive a service establishment attempt from one group; and admit the service in the network depending on the granularity of the network topology, the link topology and/or the partitioning of the link topology.

Abstract: A method for characterizing an optical focusing defect of an image capture instrument is based on contrast values. Said contrast values are calculated for two images of a same scene portion, captured in respective overlapping length segments of two image sensors. To this end, the sensors are mounted in an image capture instrument so that the overlapping length segments between the sensors are situated at different heights along a focusing direction perpendicular to said sensors.

Abstract: A device for determining the attitude or variation in attitude of a satellite fitted with an attitude control system comprising at least one inertial actuator. The inertial actuator comprises a rotary element mounted to rotate about an axis of rotation. The rotation of the rotary element is controlled to generate a torque to control controlling the attitude of the satellite. The angular sensor of the device measures the angular rotation of the rotary element about its axis of rotation. The computation unit determines the attitude or variation in attitude of the satellite induced by the rotation of the rotary element as a function of the measurements of angular rotation of the rotary element by the angular sensor. A satellite carrying such a device and a method for determining the attitude or variation in attitude.

Abstract: According to the invention, the device (1) comprises a bolt (6) including a locking member (9) which is mounted such that it can slide with respect to a first component (2) and can adopt a locked position in which the locking member (9) retains the second component (3) and an unlocked position in which the locking member (9) releases the second component (2), the transition from the locked position to the unlocked position taking place under the action of pyrotechnic means (5). In addition, a branch (4) that is at least partially deformable under the action of the pyrotechnic means (5) is arranged with respect to the bolt (6) in such a way that the transition from the locked position to the unlocked position takes place by means of the deformation of said branch (4).

Abstract: A method for calibrating spatial errors induced by phase biases having a detrimental effect on the measurements of phase differences of radio signals received by three unaligned receiving antennas of a vehicle. An inter-satellite angular deviation of a pair of satellites is estimated in two different ways: on the basis of the respective positions of the vehicle and of the satellites to obtain a theoretical inter-satellite angular deviation; and on the basis of the respective directions of incidence of the satellites relative to the vehicle, which are determined from phase measurements, to obtain an estimated inter-satellite angular deviation. The space errors are estimated on the basis of said theoretical and estimated inter-satellite angular deviations. Also, a method and system for estimating the attitude of a vehicle, in particular a spacecraft.