Abstract: A broadband satellite antenna for producing a dual-band multiple beam coverage in transmission and reception based on an offset dual-optics configuration that includes a single main parabolic reflector, a hyperbolic sub-reflector, a first transmitting Multiple-Feed-per-Beam feed system, and a second receiving Multiple-Feed-per-Beam feed system. The sub-reflector surface is a Frequency Selective Surface configured to transmit any electromagnetic signals in the higher frequency band and to reflect any electromagnetic signals in the lower frequency band. The Multiple-Feed-per-Beam feed systems are located at the main focal point FMO and at the first sub-reflector real focal point FSreal. The eccentricity e of the hyperbolic sub-reflector depends on a ratio between a preset lower frequency fL in the lower frequency band BL and a preset higher frequency fH in the higher frequency band BH.

Abstract: A method for compensating signal distortion in an emitting payload including determining a compensation transfer function and introducing it within the aggregate response of the payload; choosing an initial tentative compensation transfer function and introducing it within the aggregate response of the payload; acquiring an output signal of the emitting payload; based on the acquired output signal and on a reference signal, corresponding to an expected undistorted output signal, performing an estimation of a residual distortion transfer function of emitting payload; and based on the estimation of the residual distortion transfer function, computing an updated tentative compensation transfer function and introducing it within the aggregate response of the payload. The estimation can be a black-box estimating and the reference signal can be generated on-purpose, and not measured from within the emitting payload.

Abstract: A radio frequency radiation module includes a beam forming network capable of applying a signal including contributions to several beams, to several channels. Each channel has a high power amplifier without redundant units, and an antenna radiating feed connected to the output of the amplifier. The beam forming network has a device for selective compensation for failure of one of the channels, increasing the power of the contribution of at least one of the signals to a beam for which the radiation is affected by the failure.

Abstract: An electrical energy generation system comprising: a plurality of photovoltaic generators connected in parallel and connected to a common load via respective DC voltage converters; and a regulator configured to vary the transconductances of said respective voltage converters to maximize the power generated by said current generators; wherein: said generators are also connected to a common input of an additional voltage converter the output of which is connected to said common load; and said regulator is also configured to vary the transconductance of said additional voltage converter to maximize the power generated by said current generators.

Abstract: An adaptive signal receiver comprising at least one blind detection unit arranged to be robust to asynchronous multiple access interference (MAI). The useful signal is detected using a user signature sequence comprised of a fixed term and a complex adaptive part having a length that extends over a number of samples within a defined observation window. Provision is made for updating automatically and periodically the complex adaptive part of the signature sequence.

Abstract: A radiometry system including an aperture synthesis antenna array type, including plural antenna elements, distributed in an antenna plane relative to at least one axis, according to a determined law. Each antenna element includes first and second coupling probes sensitive to hyper-frequency electromagnetic signals with dual linear polarization in quadrature (arbitrarily referred to as horizontal and vertical polarizations). The probes are connected two by two with electric receiving circuits to create a synthetic aperture. The horizontal (fH1-fH4) and vertical (fV1-fV4) coupling probes of successive antenna elements (eA1-eA4) are oriented in the antenna plane (At′), along each of the axes (&Dgr;), such that at least one of the horizontal or vertical probes (fH1-fH4, fV1-f4) presents a 180° phase shift from one antenna element to the other (eA1-eA4), with the phase shift obtained by a sequential 90° rotation of those probes (fH1-fH4, fV1-fV4).

Abstract: The invention relates to an incoherent Doppler laser detection and ranging system of the Lidar type comprising an emission laser and a receiver device including at least one telescope, an edge filter, and processor means responsive to the power PT transmitted by the filter. The processor means has data inputs relating to the power PT and to the power PR and outputs a normalized signal &Dgr;PN, where: Δ ⁢   ⁢ P N = P T - P R P T + P R PR designating the power reflected by the edge filter.

Abstract: An apparatus for measuring fallout of particles on a surface of the type using a telltale plate which is exposed for a particular time period to the fallout of the particles. The apparatus illuminates the telltale plate when it is inserted into the measuring apparatus with the illuminating structure being adapted to emit at least one light beam substantially parallel to the upper surface.

Abstract: The invention relates to a lubrication system for a mechanism (27), on-board a spacecraft. It comprises a non pressurized tank (20) communicating with the mechanism (27) via a tube (220). A piston (23) closes the tube (220) while the mechanism is at rest. The piston (23) is controlled by a first spring (5) and by a second, shape memory, spring (24) opposing the latter, which lengthen by thermal effect. A controller (25, 26) supplies this spring with a current (I) to actuate it. An annular element(7), pushed by a cylindrical spring (6), defines a capillarity filled pumping chamber (22). When the temperature of the shape memory alloy (24) falls back below a threshold, the spring (24) recovers its original shape, the first spring (5) pushes back the piston (23) and expels a dose of lubrication fluid (4).

Abstract: The invention relates to a navigation system receiver comprising at least two antennas, one of which is a "reference" antenna. A multiplexer multiplexes the signals from the antennas, and a first processor situated downstream from the multiplexer delivers at least one navigation parameter on the basis of the signals from the multiplexer. The receiver includes a second processor having an input receiving in continuous manner signals from the reference antenna to deliver at least one reference signal representative of a position parameter of the reference antenna. Processor means process the signals from the multiplexer while taking account of at least one said reference signal.

Abstract: The invention concerns an interferometric hyperfrequency radiometry system comprising an antenna being subject to a rotation movement around the vertical direction, with a boresight axis forming an angle with a nadir direction so as to obtain a conical scanning. The antenna is a planar array antenna, of an interferometric type with distributed elements, such that the instantaneous field of vision consists of pixels, along at least one axis perpendicular to the conical scanning for an unidimensional interferometric antenna, and along two axes for a bidimensional interferometric antenna. The elements of the interferometric antenna furthermore are connected into sub-arrays.

Abstract: A reconfigurable zonal beam forming system for an antenna on a satellite in orbit includes, in cascade, a signal splitter applying signals of equal amplitude to each channel, first variable phase-shifters and amplifiers and a Butler matrix the outputs of which are connected via second variable phase-shifters to the radiating source elements of the antenna. Varying the phase-shifts introduced by the first and second phase-shifters reconfigures the transmitted beam optimally. A preferred variant of the system further includes variable attenuators. A control device is used to apply optimization parameters. A method of optimizing the resulting configuration uses a gradient search algorithm.

Abstract: A receive and/or transmit microwave planar array antenna is of the multiplate stack type comprising a plurality of slot radiating elements disposed along the rows and the columns of a matrix. The basic stack comprises three ground plates incorporating openings and two independent excitation circuit planes, enabling transmission or reception of two inclined beams. At least two other excitation circuit planes are provided so that each beam can additionally have dual polarization. The excitation circuits are microstrips, coplanar waveguides, dipole lines, of the loop or slot type, or a combination of such lines. Two consecutive lines are oriented at 90.degree. to each other. Applications include individual reception from two geostationary television satellites.

Abstract: The disclosed mount comprises a first dihedral (ABC, BCD) of which one of the planes (ABC) is borne on a support base; means (6) for adjusting the angle (.alpha.) of said first dihedral; a second dihedral (BCD, BDE) of which one of the planes (BCD) is common to the first dihedral and the other plane (BDE) carries means (8) for supporting the antenna, the axis (BC) of the first dihedral and the axis (BD) of the second dihedral being neither parallel nor merged; and means (7) for adjusting the angle (.beta.) of said second dihedral.

Abstract: Ergols, particularly for propelling missiles, containing at least one oxidant, a fuel and an energy-releasing binder. The oxidant is selected from the group which includes a nitroformate of a nitrogen compound, particularly hydrazinium or ammonium nitroformate, and a perchlorate of a nitrogen compound, particularly nitronium or ammonium perchlorate. The fuel is selected from the group which includes boron and boranes, aluminium and aluminium hydribe. The energy-releasing binder is selected from the group which includes polyglycidyl nitrate, polyglycidyl azide, polynitromethoxymethyloxetane and poly-3,3bis(azidomethyl)oxetane. Said ergols are particularly useful for propelling aerospace missiles, particularly rockets.

Abstract: The invention concerns a system for transmission of spatial diversity radio signals via a geostationary main communication satellite and one or more auxiliary satellites "colocated" in the same orbit. The distance between an auxiliary satellite and the main satellite is in the range from 200 km to 400 km. The system includes conventional bidirectional transmission links between terrestrial mobile terminals and the main satellite and between the latter and a terrestrial station. Additionally, unidirectional transmission links are provided between the auxiliary satellites and the main satellite. Applications include a mobile communication service with portable terminals via a geostationary satellite.

Abstract: A system for synthesizing a microwave filter including a plurality of resonators having no tuning elements, in particular waveguide filters for use in satellite telecommunications networks. Signals representing the coupling coefficients of the coupling elements having a finite thickness and the resonant frequency of the resonators are stored in an electronic memory. A computation unit is controlled by a control unit arranged to determine automatically, in a single run, the widths of the coupling elements and the lengths of the resonators from the signals representing the coupling coefficients.

Abstract: An altimetry method uses one or more sources of opportunity, for example transmitters on satellites of the "GPS" satellite navigation system. One or more receivers on board an aircraft or a satellite in low Earth orbit are used. Multiple correlation is applied between the direct signal received from the transmitter and the reflected signal. The coordinates of the point of specular reflection are derived from the measured delay achieved by said multiple correlation and comparison with a theoretical model of the terrestrial sphere. The device for implementing the method includes a signal processor, a variable delay circuit, a discrete delay line, a bank of correlators and detectors. A specific application of the method and device is ocean altimetry.

Abstract: The present invention relates to a photocell including means for providing protection against the accumulation of electrostatic charge, to a method of manufacturing it, and to a solar panel including such cells.A photocell of the invention includes a circuit for drawing off electrostatic charge that is efficient but is of low mass and that masks incident solar radiation very little.The circuit for drawing off charge comprises a grid of material that is optionally transparent on the outside surface of the protective glass sheet of the photocell, said grid being connected to the cell's electrode for current collection. Advantageously, the grid of the circuit for drawing off electrostatic charge is superposed over the grid of the electrode for collecting the current generated by the photocell.

Abstract: A compact range for the determination of the radiation pattern of a first antenna (1), comprises a focusing system (3) and apparatus (2) supporting the first antenna in the quiet zone of the focusing system. For that purpose, the base comprises a modulated-retransmission probe array (6, 16) mounted in the focal plane (7) of the focusing system, a second antenna (10, 17) mounted near the probe array, apparatus (13) to determine, from the electromagnetic radiation retransmitted by the probe array and collected by one of the antennas during the transmission of electromagnetic radiation by the other, a signal SI representing the field at each point of the probe array, and a display (14) for displaying the signal.