Abstract:
An actuator includes a body (1), a unit (2) that is able to move with respect to the body, two end stops, at least one of which is able to move with respect to the body and carries along the mobile unit under the effect of its own movement, a motor winding (41, 42) made of shape memory material and having at least one stable form, known as the memorized shape, being interposed between the two end stops which are spaced apart from one another at a different spacing depending on the shape of the motor winding, the mobile unit being moved under the effect of a variation in this spacing, characterized in that the motor winding is a winding having contiguous turns that are deformed from a first shape different from a memorized shape to a memorized shape by flexural deformation common to all the turns.
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:
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.
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 frequency-tunable microwave-frequency wave filter with dielectric resonator, comprises a metallic cavity and at least one stack along a rotation axis, the resonator-forming stack being disposed inside the cavity and comprising at least a first and a second element each made of dielectric material, the second element being mobile in rotation with respect to the first element around the rotation axis and exhibiting a first position and at least one second position separated by an angle of rotation, and the elements exhibiting shapes such that the overall geometry of the stack is different in the at least two positions, the stack forming a first resonator adapted so that the filter exhibits a first central frequency when the second element is in the first position, and forming a second resonator adapted so that the filter exhibits a second central frequency when the second element is in the second position.
Abstract:
A band-pass filter for microwave is provided that can be frequency-tuned the filter comprising an input resonator comprising a metal input cavity and an input dielectric element, an output resonator comprising a metal output cavity and an output dielectric element, an input excitation means (S1) of elongate shape, an output excitation means of elongate shape, the input resonator and the output resonator being coupled, characterized in that the input dielectric element and the output dielectric element have a recess, the input excitation means penetrates the recess of the input dielectric element the output excitation means penetrates the recess of the output dielectric element, the input dielectric element is capable of carrying out a rotation about an input rotation axis, the rotations of the dielectric elements allowing the modification of the central frequency of the filter.
Abstract:
A device is suitable for revealing spatial variations in polarization of an electromagnetic radiation, in a form of localized temperature variations. The device includes a surface of a carrier which is electrically and thermally insulating, and includes an array of patterns which each consist of at least one rectilinear segment of a sensitive material, of which the orientation is variable within each pattern or between neighboring patterns. Such device may be used with a thermal camera to reveal, in infrared images, temperature variations which are localized at segments not perpendicular to a local direction of linear polarization of the radiation.
Abstract:
A device is suitable for revealing spatial variations in polarization of an electromagnetic radiation, in a form of localized temperature variations. The device includes a surface of a carrier which is electrically and thermally insulating, and includes an array of patterns which each consist of at least one rectilinear segment of a sensitive material, of which the orientation is variable within each pattern or between neighboring patterns. Such device may be used with a thermal camera to reveal, in infrared images, temperature variations which are localized at segments not perpendicular to a local direction of linear polarization of the radiation.
Abstract:
A terminal to calculate a position and detect spoofing, the terminal includes a receiver of first signals, notably signals of a GNSS type, from first sources, to compute a first information relative to its position, as for instance a pseudo range measurement, an ephemeris, a navigation message, spatial coordinates or temporal coordinates, and to calculate a position; a receiver of a second signal of a non-RF and non-GNSS type from a second source, notably from an optical display, the second signal comprising a second information transmitted using a predetermined encoding format to retrieve said second information; a processing logic configured to detect spoofing by comparing the first and second information. The associated transmitters, authentication server and spoofing detection methods are also provided.
Abstract:
Computer systems (100) for satellite image acquisition and mission-plan calculation devices (120) for satellite and also Earth observation satellites (110). Based on the observation that the uncertainty connected with meteorological conditions can lead to the development of mission plans, for satellites, with low effectiveness, the uncertainty is characterized and used to improve the preparation of mission plans for satellite. A model of the uncertainties is built upon observations and/or past meteorological forecasts. Next, at the time of planning, the model is used by presenting the observations and/or the current forecast as input to the model. In that way, the acquisition zones for which it is unlikely to get acceptable images on the preferred acquisition date may be identified.