Agence Spatiale Europeenne

Luigi Bella

Mario Lopriore

Stefano Badessi

Javier V-t Bosch

Francois-Xavier Benedicto Ruiz

Claudio Soprano

Irene Echaniz-Elgarresta

Bernhard Grafmueller

Gerhard Hoffmann

In accordance with the invention, the digital samples associated with each of the array elements arranged along a plurality of parallel lines are shifted by a distinct predetermined number of positions along each of said lines, and the digital samples of each line are added separately. Thereafter, each sum thus obtained is multiplied by a distinct phase coefficient. The signals thus obtained for each beam are all in phase. The lines of array elements that are electronically scanned can be oriented along any direction, and advantageously along one or a plurality of diagonals of the array and the electronic scanning of the array elements can be made separately along odd alternate diagonals and along even alternate diagonals.

Method and system for digital beam forming

The invention concerns a method and a system for transmitting radio signals between a fixed terrestrial station and mobile user terminals via a network of satellites in inclined circular orbits having a radius less than that of geostationary orbits. The beams generated are divided into pencil beams each associated with a continuous sub-band of frequencies in increasing frequency or decreasing frequency order. The instantaneous transmission frequency is offset progressively during the call towards the frequency subband of the adjacent pencil beam, at a rate proportional to the orbital rotation speed, to enable switching between pencil beams or between satellites. Applications include transmission via satellites in non-geostationary orbit.

Method and system for transmitting radio signals between a fixed

A procedure for control of a scanning antenna including:

procedure for controlling a scanning antenna

A satellite receiver is provided which downconverts an incoming band of signals received at a carrier frequency to a signal spectrum centered about an intermediate frequency (IF). The IF signal spectrum is filtered to provide a group of signals therefrom. The group comprises a subset of all the signals in the incoming band of signals. The group of signals from the IF signal spectrum is sampled at a high frequency which is greater than the highest frequency present in the group but lower than the intermediate frequency, in order to provide the group of signals at baseband directly from the IF signal spectrum.

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Noordwijk-aan-Zee, Netherlands

Luigi Bella