Abstract: A multiple-reflector antenna for telecommunications satellites including a shaft, to which are attached at least two sub-reflectors, rotating in relation to a load-bearing structure, and a motor including a rotor able to drive the shaft in rotation, and a stator attached to the load-bearing structure, wherein the multiple-reflector antenna also includes two bearings enabling the shaft to rotate in relation to the load-bearing structure, a torsionally rigid mechanical filter placed between the shaft and the rotor, enabling the rotor to transmit the rotational movement to the shaft, and able to dampen the stresses generated by the shaft on the motor, and locking means able to hold the angular position of the shaft in relation to the load-bearing structure.

Abstract: The invention relates to a polarization-insensitive optical filter centered on a wavelength measured in vacuum, comprising: first and second waveguides each having a propagation mode; a first grating formed in or on the surface of the first waveguide, the first grating being periodical at least along a first axis Ox defining a first orthonormal base Oxyz; a second grating formed in or on the surface of the second waveguide, the second grating being periodical at least along a second axis Ox? defining a second orthonormal base Ox?y?z; wherein the first and second grating are provided one above another and are such that the first axis Ox and the second axis Ox? define an angle ? different from ±?/2 radians so that, when the first grating is illuminated by a light beam, the propagation modes are excited and have orthogonal fields for an angle of incidence of the light beam.

Abstract: A method for transmitting data between a terminal and a gateway, the data being transported by Ethernet frames comprising an Ethernet header and a payload, which are themselves encapsulated in lower level packets each comprising a header containing a medium access address, comprises the following steps: determining contexts common to frames whose Ethernet headers have identical fields, and defining an identifier of each the context; associating all or some of the frames with the corresponding context identifiers and suppressing the fields from their Ethernet headers; and introducing the context identifier of each frame for which the fields of the Ethernet header have been suppressed from the header of the lower level packet encapsulating it by replacing its medium access address. A method for receiving data transmitted by means of such a method.

Abstract: A method for identifying transmitters by a terminal in a single-frequency network comprising a plurality of transmitters. The transmitters are synchronized and transmit with an artificial delay ?i, specific to each transmitter. The method comprises at least one step of acquiring the approximate position of the terminal {circumflex over (p)}, the position pi of a list of transmitters {Tx} in the vicinity of the terminal and the delays ?i associated with them, a step of measuring pseudo-distances ?i between the transmitters and the terminal and a step of associating the measurements ?i with the transmitters of known positions pi by minimizing a cost function, said cost function ?(?i,{circumflex over (p)},?) corresponding to the norm of the error between the measurements ?i and a model of measurements of the pseudo-distances applied to a permutation of the position of the transmitters ?.

Abstract: A device (1) for draining a tank of fluid under pressure pertaining to a space system includes a pyrotechnic actuator that is suitable to perforate a conduit (2) in fluid communication with the tank, the device including a collar (4) that is suitable to enclose the conduit, the collar bearing: a pyrotechnic cartridge (5) for perforation, oriented radially towards the conduit (2), and an anvil (11), diametrically opposed to the cartridge in relation to the conduit, that is suitable to collect debris generated by the perforation.

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 includes at least one built-in flexible portion (1) between two stiffer portions (10) that are made of a stiff composite material, the flexible portion (11) being suitable for forming a flexible hinge and made of a flexible material including a reinforcing armature that includes at least one connecting layer (13) common to the material(s) forming each stiff portion (10). The device has end surfaces (20) that oppose each other when extended, the opposing end surfaces being arranged to be suited to serve as a longitudinal compression abutment while enabling the thus-made hinge to fold back at least in a direction away from the extended state.

Abstract: A satellite cellular radio-communication system using beam formation is provided. The system includes a satellite, at least one satellite access station, terminals, at least one control unit of a virtual cell. At least one of the terminals is configured to transmit and receive on a transmission channel having at least two frequency and spatial transmission resources of a same virtual cell that are different by their frequency band, a frequency and spatial transmission resource being a sub-band of a frequency band used in a beam. The frequency band is taken from among a predetermined number of frequency bands and was allocated to said beam according to a reuse function.

Abstract: Method for calibrating a linearizer and linearized electronic component the method comprises predistortion, in a predistortion linearizer, of a signal upstream of an electronic component to compensate nonlinear distortion. Determining predistortion setting parameters comprises applying a bifrequency test signal to the component and measuring the relative amplitudes of the lines at the output of the component. A variable indicative of the magnitude |Kp| of the AM/PM conversion coefficient of the component is calculated on the basis of these measurements. The predistortion setting parameters are adjusted so as to minimize |Kp|. The method may in particular be implemented in a linearized amplifier device and in an amplifier test bench.

Abstract: The converter comprises an inverter powered by a DC current source. The inverter powers a conversion unit operating on the basis of controlled magnetic switching obtained by means of power diodes and saturable inductors. A regulator can be used to produce a control voltage that is a function of the output voltage which is regulated with the injection of the control voltage into the circuit comprising the smoothing inductors. According to the invention, during each operating cycle, one of the power diodes is locked when the other power diode switches to conduction mode, such as to create a phase displacement between the input voltage of the conversion unit and the input current of same. The phase displacement angle is a function of the control voltage.

Abstract: The invention concerns a helical antenna comprising a shape of revolution and a plurality of radiating strands helically wound around the shape of revolution, characterised in that each radiating strand is defined by a repetition of a fractal pattern comprising segments formed by a sinusoidal curve.

Abstract: The invention concerns a device for preventing the establishment of an electric arc between adjacent portions (9) having no electrical insulation of at least two electrically conductive elements (7). According to the invention, the device comprises at least one separating partition (13) made of dielectric material inserted between said adjacent portions (9) of said conductive elements (7), the dimensions of said separating partition (13) being adapted so that the shortest path between said adjacent portions (9), by bypassing said separating partition (13), corresponds to an instability threshold for an electric arc that is likely to be established between said adjacent portions.

Abstract: A method of acquiring, compressing and transmitting satellite images, characterized in that in a systematic manner: an image is acquired (101); (102) the image is processed by an image preprocessing step providing a value characteristic of the image and an image preprocessed by recognizing predetermined natural objects in the acquired image and replacing the natural objects by standard objects; the characteristic value is compared (103) with a table of values, each value of which is associated with a compression algorithm; the compression algorithm corresponding to the characteristic value is implemented (104) by compression elements for compressing the image; the compressed image is transmitted (105) to a remote image reception device by transmission elements.

Abstract: This invention relates to a propulsion bay to be transported, at least temporarily, in a space launch vehicle and comprising an adapter that co-operates with at least one system located, at least temporarily, on board the bay, said system comprising an electrical power supply. The bay is characterized in that it also comprises at least one electric space propulsion engine that can be powered by the power supply of the system.

Abstract: A method and a device for deflating an inflated wall (1), wherein the inflated wall (1) is cut by using at least one cutting member adapted to cut the inflated wall (1) along a cutting line with the effect of causing a deflation opening of the inflated wall (1). The invention applies in particular to the inflated envelope of an aerostat balloon.

Abstract: An image processing system in which the georeferencing of at least one digital image is achieved by means of at least one picture model of the said digital image and of a digital reference relief form. The digital image is obtained from a pair of digital images acquired in the same focal plane. An intermediate digital relief form is produced from said pair of digital images. The intermediate digital relief form and said digital reference relief form are processed to refine the said picture model of the said digital image to be georeferenced. A final digital relief form is generated and said final digital relief form and said digital image are projected in a geographical or cartographic system, for the purpose of their georeferencing. The pair of digital images in the same focal plane are acquired in a small stereoscopic base configuration by sensors located in the same focal plane.

Abstract: Optical devices can comprise a deformable mirror and a system for deforming said mirror. A deformation system comprises a first mechanical structure comprising a first surround, one or more electromechanical actuators attached to the first mechanical structure, a second mechanical structure comprising a substantially planar bottom and a second surround, both deformable, the bottom being attached to the first surround, the second surround being attached to the surround of the mirror, a rigid stud being attached to the bottom, substantially planar and centerd on the bottom, the electromechanical actuator or actuators exerting predetermined forces or bending moments on the stud so as to generate a particular distribution of the bending moments on the surround of the mirror, deforming it according to a geometrical form representative or of one or more predetermined geometrical aberrations.

Abstract: The invention relates mainly to a test bench (10) for a radial bearing (14) suitable for being interposed between two members (12, 16) that are movable relative to each other in rotation, the test bench being characterized in that it comprises a radial force measurement device (18) for measuring radial forces exerted on said bearing (14), a radial acceleration measurement device (20) for measuring radial accelerations to which said bearing (14) is subjected, and an electronic calculation unit (26) in communication with the radial force measurement device (18) and with the radial acceleration measurement device (20). The invention also relates to a method of establishing a behavior relationship for the radial bearing (14).

Abstract: A waveguide orthomode transducer, comprises: a junction having a main waveguide and four auxiliary waveguides lying along the two orthogonal main axis of the junction and defining four quadrants; a combination network comprising: two magic tees, each having an E-port, two opposed common-ports, and a H-port; an H-plane tee junction having a ?-port and two opposed common-ports; and an E-plane tee junction having a ?-port and two opposed common-ports. Two auxiliary waveguides define a first quadrant are respectively connected to the common-ports of one of the magic tees and the two other secondary waveguides defining a second quadrant opposite to the first quadrant are connected to the common-ports of the other magic tee. The tee junctions are used to connect similar magic tee ports so that the transducer separates towards two different outputs two orthogonally polarized signals entering at the main waveguide.

Abstract: A system and method for detecting and locating an insulation flaw in a solar generator on a spacecraft. The solar generator comprises a plurality of flaps. Each flap bears at least one solar cell that is connected to an electrical distribution network and electrically insulated from the flap. Each flap is connected, by a first load and by a second load, to a first electrical line and a second electrical line, respectively. The ratio of the impedances of the first load and of the second load of a flap being denoted as an impedance ratio of the flap. The solar generator comprises at least two flaps exhibiting different respective impedance ratios. The system comprises a component for evaluating the currents flowing in the first and second electrical lines, and a detector for detecting and locating an insulation flaw in the solar generator based on the evaluations of the currents.