Thales Alenia and French National Center for Space Studies | Date: 2016-09-16
A dual guidance gyroscopic actuator comprises, a main structure connected to a platform, connected to a satellite, a ring, a U-shaped cradle, having first and second ends and a central part, a flywheel mounted on the central part between the first and second ends, being rotationally mobile with respect to the cradle about a first axis. A first bearing is positioned at the first end and a second bearing is positioned at the second end connecting the ring to the cradle, the first and second bearings rendering the cradle rotationally mobile with respect to the ring about a second axis substantially perpendicular to the first axis. The ring is connected to the main structure. The gyroscopic actuator comprises at least one suspension element limiting microvibrations from the cradle and flywheel and at least one end-stop element limiting travel cradle and of the flywheel with respect to the main structure.
Snecma and French National Center for Space Studies | Date: 2016-11-10
A feed system for feeding a rocket engine with a liquid propellant includes a feed circuit, and a device to vary a volume of gas in the feed circuit. The device is configured to cause a volume of gas in the feed circuit to vary while the rocket engine is in operation. The device to vary gas volume includes at least one variable-flow-rate gas injector to inject gas into the liquid propellant in the feed circuit. Methods of suppressing a POGO effect are also provided.
French National Center for Space Studies | Date: 2017-01-11
The invention discloses a receiver of GNSS positioning signals which has embedded computer logic to select between a first operating mode, which uses all available frequencies, and a second operating mode, which uses only part of the available frequencies but in combination with available correction data. The selection is based on a comparison of an index of quality of reception at the receiver and a computed or predicted precision/confidence level of the corrections. A plurality of corrections types are possible, including a type using a local model and a type using collaborative corrections. In some embodiments, a selection and/or a combination of a plurality of local models may be made to optimize the accuracy of the corrections.
French National Center for Space Studies and M3 Systems | Date: 2017-01-04
A receiver, and associated process, for tracking a GNSS positioning signal comprising a carrier modulated by a subcarrier and a spreading code, the receiver comprising:- at least one tracking loop configured to calculate a first pseudo range from said GNSS positioning signal,- a first discrimination circuit (521) configured to calculate an ambiguous discriminator value from the subcarrier and the spreading code of said GNSS positioning signal,- a calculation circuit (522) configured to calculate a value representative of a tracking error of said tracking loop,- a second discrimination circuit (530) configured to select one of said ambiguous discriminator value and said value calculated by the calculation circuit, and to generate a first non-ambiguous discriminator value, an amplitude of which is based on an amplitude of the selected value, and a sign of which is a sign of said value calculated by the calculation circuit.
Thales Alenia and French National Center for Space Studies | Date: 2016-10-06
A distributed amplification device with p inputs, p outputs, p amplification paths comprises a redundant reservoir of n amplifiers including n-p back-up amplifiers, an input redundancy ring and an output redundancy ring formed by rotary switches, the input and output redundancy rings sharing the same technology. The internal amplification pathways associated with the n-p back-up amplifiers frame in an interlaced manner the internal amplification pathways associated with the p nominal amplifiers and the amplification paths of the routing configurations each pass through at least five rotary switches. The input and output redundancy rings are topologically and geometrically configured and the family of the routing configurations is chosen such that the electrical lengths of all the paths of one and the same routing configuration of the family are equal.
French National Center for Space Studies | Date: 2017-01-18
The invention relates to a device (1) for absorbing electromagnetic waves, comprising a plurality of arrays (Ei) each comprising at least one cell (2) for absorbing electromagnetic waves, characterised in that: each array (Ei) has a minimum absorption coefficient valid for given parameters of the waves incident on said array (Ei), said parameters comprising one or more of the following parameters: - a pair of angular ranges ([i-i],[i-i]) of the direction of arrival of the incident waves on the array (Ei), comprising a range ([i-i]) of angles of incidence and a range of azimuthal angles ([i-i]), and - a polarisation of the incident waves, the parameters of the incident waves for which each array (Ei) ensures the minimum absorption coefficient being different from one array (Ei) to the other. The invention also relates to a method for designing and producing an absorbing device.
French National Center for Space Studies | Date: 2016-11-16
French National Center for Space Studies | Date: 2015-05-13
This system includes: a database including maps, each map being associated with an infrastructure from a plurality of available infrastructures and providing, at each point of a geographical zone, a local value of a property relative to a quality of experience associated with the execution of an application accessing a remote resource through the infrastructure; a localization element generating a current position of the mobile terminal; a selection element for selecting a trajectory; a correlation element able, from the current position, the selected trajectory, and each map, to determine a correlation coefficient; and a selection unit able, based on the correlation coefficients, to select an infrastructure from among the plurality of infrastructures.
French National Center for Space Studies | Date: 2017-03-22
This system (30) comprises: - a database (31) comprising maps (Cik), each map being associated with an infrastructure from a plurality of available infrastructures and giving, at each point of a geographical area, a local value of a quantity relating to a quality of experience associated with the execution of an application accessing a remote resource via the infrastructure; a localisation means (20) generating a current position of the mobile terminal (10); a means (40) for selecting a path; a correlation means (50) capable of determining a correlation coefficient, from the current position, the selected path, and each map; and a selection means capable of selecting an infrastructure from the plurality of infrastructures, based on the correlation coefficients.
French National Center for Space Studies | Date: 2017-05-24
The positioning receiver according to the invention comprises means for storing configuration information and information on its reception conditions, which is processed in order to calculate a current and/or predicted precision of the positioning calculation. Advantageously, at least some of this information is integrated into a variation model of a Kalman filter integrated into the receiver. The invention notably allows a more rapid convergence on a reference precision in a mono-frequency operating mode and transitions between a mono-frequency and bi-frequency mode to be smoothed. Advantageously, the precision information is delivered graphically or in numerical form to the user.