Abstract:
A broadband multi-beam satellite radiocommunication system configured to implement a scheme for re-use of frequencies from a total band allocated to an uplink comprises a satellite with a multi-beam receive antenna that forms adjacent reception spots of a terrestrial coverage. Each reception spot consists of a central inner zone and a peripheral zone. Each central inner zone is a cellular pattern identical except for a scale factor to geographical cells wherein the principal frequency sub-bands of a bundle of separate or adjacent principal sub-bands are unitarily distributed and the combination of which is equal to a principal band, included in the total band.
Abstract:
A method and device are provided suited to estimating a frequency value for aeronautical communication between a first station and an airborne system moving in relation to the first station, the data being transmitted in the form of a succession of frames, a frame comprising at least one first header field of known data followed by one or more fields of unknown data, and having at least the following steps: Step 1: performance of a supervised correlation on the known data (300) of the header, and estimation of a first frequency range centered on a frequency ; Step 2: production of a blind correlation on at least all of the unknown data of a field of data, by looking for a correlation peak over the frequency range +/−, as determined in step 1, and by retaining of the frequency corresponding to the correlation peak.
Abstract:
A broadband multibeam satellite radio communication system is configured to cover a geographical service area that is broken down into a plurality of transmission spots that are each made up of a central internal area and a peripheral area. A first polarization state and a second polarization state are respectively allocated to the spots of a first grid G1 and the spots of the second grid G2. One and the same main band BP of frequencies is allocated wholly to each central internal area. The coverage of the quadruple points service area is a pavement of elemental useful surfaces or coverage meshes having the shape of a parallelogram.
Abstract:
An antenna with polarization switching comprises a support comprising at least two faces each supporting a plurality of waveguides fed with radiofrequency signals and pierced with apertures disposed so as to illuminate radiating elements placed some distance from the said apertures. For at least one given antenna pointing, the said support is able to toggle between at least two different configurations, the said support being configured so as to place, in the second configuration, the second face in a position identical to that taken by the first face in the first configuration, several radiating elements of the first face being, in the said position, oriented differently from radiating elements of the second face. It applies notably to the switching of antennas embedded onboard moving objects on the ground having to operate high-speed communications with a satellite, in particular a geostationary satellite.