Abstract: The invention relates to a radar system comprising: a frequency synthesizer, configured to generate a modulated local signal (Sf0+?f0); at least one frequency multiplier, configured to supply an intermediate-frequency local signal (Sf_inter+?f_inter) to each emission channel (8) and to each reception channel, the intermediate-frequency local signal (Sf_inter+?f_inter) being a fractional multiple of the modulated local signal (Sf0+?f0); a plurality of emission frequency transposition components, the emission frequency transposition components being synchronized with one another by the modulated local wave (Sf0+?f0); a plurality of reception frequency transposition components, the reception frequency transposition components being synchronized with one another by the modulated local signal (Sf0+?f0), the reception channels being configured to demodulate the intermediate-frequency reception signal (Sf_inter_Rx+?f_inter_Rx) using the intermediate-frequency local signal (Sf_inter+?f_inter).

Abstract: The invention relates to a MIMO imaging radar system. The system comprises transmission channels (Ve1, VeM), reception channels (Vr1, VrN), and co-located radiating elements (ERe1, EReM, ERr1, ERrN) forming a two-dimensional antenna array. Each radiating element (ERe1, EReM, ERr1, ERrN) has a predefined instantaneous field of coverage. Each radiating element is formed by a plurality of p radiating sub-elements (SeElt1, SsEltp) distributed in at least one of the two dimensions of the antenna array. The radar comprises a plurality of electronic steering modules (MDe1, . . . , MDrN). Each electronic steering module is connected to one radiating element. Each steering module is configured to apply a steering command (Cmd) between all the radiating sub-elements (SeElt1, SsEltp) of a given radiating element. The steering command (Cmd) is identical from one radiating element to the next, so as to move the field of coverage of each radiating element in the same direction.

Abstract: A space-based augmentation system improving the accuracy and reliability of satellite navigation system data includes, each at least: a ground station transmitting data to satellites, a ground station receiving signals transmitted by a satellite and by a satellite equipped with transmitting/receiving means for transmitting data received from the ground transmitting station for a given geographical area; two ground computing centers, redundantly and respectively calculating navigation message streams and transmitting to the ground transmitting station navigation message streams and information representative of Quality of Service provided by the system, from signals transmitted by the ground receiving stations. The computing centers, ground receiving station and ground transmitting station are connected by a communication network.

Abstract: An adaptive method for estimating the electron content of the ionosphere comprises: collecting a set of measurements carried out by a plurality of beacons receiving radio frequency signals transmitted by a plurality of transmitting satellites; computing coordinates of the points of intersection between the transmission axis of the signals and a surface surrounding the Earth, and of a vertical total electron content determined at each of these points; computing a vertical total electron content for each of the nodes of an initial mesh of the surface; a statistical dispersion analysis of the vertical total electron content; a computation step making it possible to define a suitable statistical estimator, or a computation step making it possible to generate a suitable mesh of the surface; a statistical error analysis making it possible to select between a validation of the adaptation of the method and a stopping of the method.

Abstract: A method of monitoring the integrity of stations for observing radio-navigation signals in a satellite based augmentation system SBAS comprises: defining a geographical zone comprising a plurality of observation stations, calculating, for each observation station of the zone and for each line of sight between the station and a satellite, the discrepancy between the theoretical pseudo-distance D and the measured pseudo-distance D?, calculating the average m of the discrepancies D?D? over the zone for at least one satellite in visibility of the zone, validating the integrity of at least one observation station of the zone if the discrepancy, for the station and for at least one line of sight between the station and a satellite, is less than or equal to the average that is multiplied by a predetermined exclusion threshold, and excluding this observation station in the converse case.

Abstract: A method of monitoring the integrity of stations for observing radio-navigation signals in a satellite based augmentation system SBAS comprises: defining a geographical zone comprising a plurality of observation stations, calculating, for each observation station of the said zone and for each line of sight between the said station and a satellite, the discrepancy between the theoretical pseudo-distance D and the measured pseudo-distance D?, calculating the average m of the said discrepancies D-D? over the said zone for at least one satellite in visibility of the said zone, validating the integrity of at least one observation station of the said zone if the said discrepancy, for the said station and for at least one line of sight between the said station and a satellite, is less than or equal to the said average that is multiplied by a predetermined exclusion threshold, and excluding this observation station in the converse case.

Abstract: An adaptive method for estimating the electron content of the ionosphere comprises: collecting a set of measurements carried out by a plurality of beacons receiving radio frequency signals transmitted by a plurality of transmitting satellites; computing coordinates of the points of intersection between the transmission axis of the signals and a surface surrounding the Earth, and of a vertical total electron content determined at each of these points; computing a vertical total electron content for each of the nodes of an initial mesh of the surface; a statistical dispersion analysis of the vertical total electron content; a computation step making it possible to define a suitable statistical estimator, or a computation step making it possible to generate a suitable mesh of the surface; a statistical error analysis making it possible to select between a validation of the adaptation of the method and a stopping of the method.