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 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: 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.

Abstract: An antenna with polarization switching comprising a plurality of waveguides fed with radiofrequency signals and perforated with apertures disposed so as to illuminate radiating elements placed on mobile support means in a plane that is distant from the said apertures, it being possible for the said support means to be configured according to at least two distinct configurations. The radiating elements illuminated according to one and the same configuration are adjacent, the support means being adapted for orienting the radiating elements illuminated in a first configuration according to a different direction from the radiating elements illuminated in a second configuration. The antenna applies notably to the switching of antennas onboard objects moving on the ground required to undertake high-speed communications with a satellite, in particular a geostationary satellite.

Abstract: An onboard directional plane antenna comprises at least one array of radiating-slot waveguides comprising an alternating succession of three superposed metallic plates and of two dielectric substrates. The two substrates each comprise at least four adjacent waveguides, corresponding and communicating with one another pairwise by way of coupling slots. Each waveguide of the upper substrate furthermore comprises a plurality of radiating slots passing through the upper metallic plate, all the radiating slots of one and the same waveguide being parallel to one another and oriented in one and the same direction, the radiating slots of two adjacent waveguides being disposed in chevrons. Each waveguide of the lower substrate comprises an internal individual feed circuit comprising an individual electronic circuit for phase shifting and amplification.

Abstract: A flat scanning antenna comprises at least one slotted waveguide array comprising two dielectric substrates, one superposed above the other. The two substrates comprise the same number of waveguides, which are in mutual correspondence and communicate between them, pairwise, via corresponding coupling slots. Each waveguide of the upper substrate further includes a plurality of radiating slots, all the radiating slots being mutually parallel and oriented in the same direction and each waveguide of the lower substrate includes an individual internal supply circuit comprising an individual phase-shift/amplification electronic circuit.

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.

Abstract: An onboard directional plane antenna comprises at least one array of radiating-slot waveguides comprising an alternating succession of three superposed metallic plates and of two dielectric substrates. The two substrates each comprise at least four adjacent waveguides, corresponding and communicating with one another pairwise by way of coupling slots. Each waveguide of the upper substrate furthermore comprises a plurality of radiating slots passing through the upper metallic plate, all the radiating slots of one and the same waveguide being parallel to one another and oriented in one and the same direction, the radiating slots of two adjacent waveguides being disposed in chevrons. Each waveguide of the lower substrate comprises an internal individual feed circuit comprising an individual electronic circuit for phase shifting and amplification.

Abstract: A flat scanning antenna comprises at least one slotted waveguide array comprising two dielectric substrates, one superposed above the other. The two substrates comprise the same number of waveguides, which are in mutual correspondence and communicate between them, pairwise, via corresponding coupling slots. Each waveguide of the upper substrate further includes a plurality of radiating slots, all the radiating slots being mutually parallel and oriented in the same direction and each waveguide of the lower substrate includes an individual internal supply circuit comprising an individual phase-shift/amplification electronic circuit.

Abstract: A relay for use in telecommunications equipment, said relay comprising: a receiver (R) adapted to receive an information stream consisting of information cells, some of which can be empty, a mixer (M) adapted to detect the empty cells and replace them with waiting cells, and a transmitter (E) adapted to transmit the cells to a receiver, which relay is characterized in that it further comprises a stream analyzer (A) for determining if an information stream is a real-time information stream or a differed-time information stream and for storing differed-time stream cells in a mass memory (MM), and in that said mixer is adapted to choose said waiting cells from among the cells stored in said mass memory.

Abstract: The invention relates to a multiplexing device comprising a data compressor. The compressed data block leaving said compressor occupies a particular bandwidth. According to the invention, a bandwidth prediction unit calculates said bandwidth and deduces from it the available bandwidth for conveyance in a time space dedicated to Internet traffic. The invention also relates to a multiplexing device and a multiplexing/demultiplexing system. Particular application in a satellite telecommunication system.

Abstract: The invention relates to a receiving antenna for satellite telecommunications. More specifically, the invention relates to an active antenna comprising a network of elementary sources which is positioned at the focal point of a focusing reflector. According to the invention, said network of sources is disposed on a more or less spherical, concave surface S. The aforementioned arrangement can be used to: (i) improve the efficiency of the optics and (ii) enable the use of polarisation duplexers behind surface S in order to increase the spectral efficiency of the antenna.

Abstract: The invention relates to a multiplexing device comprising a data compressor. The compressed data block leaving said compressor occupies a particular bandwidth. According to the invention, a bandwidth prediction unit calculates said bandwidth and deduces from it the available bandwidth for conveyance in a time space dedicated to Internet traffic. The invention also relates to a multiplexing device and a multiplexing/demultiplexing system. Particular application in a satellite telecommunication system.

Abstract: The invention relates to a receiving antenna for satellite telecommunications. More specifically, the invention relates to an active antenna comprising a network of elementary sources which is positioned at the focal point of a focusing reflector. According to the invention, said network of sources is disposed on a more or less spherical, concave surface S. The aforementioned arrangement can be used to: (i) improve the efficiency of the optics and (ii) enable the use of polarisation duplexers behind surface S in order to increase the spectral efficiency of the antenna.

Abstract: The invention concerns a method of communication between ground stations via satellites traveling around the Earth and forming part of a constellation overflying at least a major portion of the Earth, each ground station communicating during a particular time with a given satellite of the constellation. Two ground stations communicate via respective given satellites with which the stations are respectively communicating. To minimize the control means on board each satellite, the two satellites communicate via a predetermined communications link. A link of the above kind generally comprises one or more predetermined satellites.

Abstract: A satellite for a satellite telecommunication system transmits signals at different powers on the downlink connection. The powers are chosen to limit the relative dynamic range of signals received on the downlink connection. The relative dynamic range of signals received on the downlink connection is advantageously less than 5 dB and preferably less than 2 dB. A digital processor circuit is used, together with an analog-digital converter, a circuit taking the fast Fourier transform of the converted signals, a circuit for monitoring the gain of the signals, a circuit for switching the signals to at least two amplifier subsystems each including an inverse fast Fourier transform circuit, a digital-analog converter and a power amplifier.

Abstract: A relay for use in telecommunications equipment, said relay comprising:

Abstract: A unit for combining N channel signals produced by N respective separate sources, where N is an integer, comprises a collector array receiving the N channel signals in respective directions defined by array lobes associated with the collector array.

Abstract: A method and a system for locating ground equipment transmitting signals to a geostationary satellite, the method and the system being based on identifying the arrival directions of such signals within the coverage zone of the satellite. In the method, the arrival directions of the signals are identified by using a beam-forming active-module array antenna system on board the satellite, the system being controlled to define simultaneous beams in the radiation pattern of the antenna, the beams being superposed on one another with small offsets, the superposed beams corresponding to a limited analysis zone being illuminated within the coverage zone of the satellite, the system further being associated with a digital processing program which identifies the arrival directions of the signals which are received in the analysis zone.

Abstract: The invention provides a multibeam antenna comprising:an array 11 of N.sub.e elementary sources 31; energy-focusing optical means comprising a reflector 10 or a lens; the array being situated in the focal zone of said focusing means: and a feed and control circuit cooperating with the N.sub.e primary sources 31 to produce N.sub.b beams each generated from a subgroup of the primary sources, some of which are shared between overlapping beams; the feed and control circuit comprising phase shifter means and attenuator means, said means being organized in N.sub.e feed channels for said N.sub.e primary sources, each feed channel including specific means for acting on the phase and the amplitude of an excitation signal in each feed channel;wherein each required beam is generated by the multibeam antenna solely by acting on the phase and the amplitude of the excitation delivered to each elementary source forming a portion of said beam; andwherein the number of sources N.sub.i contributing to a beam i, 1.ltoreq.i.