Thales

Jean-Christophe Levy

Alexandre Guerin

Arnaud Guerin

Jean-Louis Damidaux

Cédric Baudoin

Mathieu Gineste

Katia Leconte

Bernard Coulomb

Thierry Quignon

Xavier Wautelet

A method for entry into a satellite communication network includes at least one satellite, the communications of the satellite communication network being organized according to a beam-hopping mechanism wherein hop frames define antenna beam configurations of the at least one satellite, wherein resources of the hop frames are reserved for forming directional entry beams dedicated to entry or re-entry of user terminals into the satellite communication network, at least two of the directional entry beams having different directions of sight. A satellite, a user terminal and a communication network configured to implement the described method.

Procedure for entry into a satcom network employing beam hopping

A method for determining operational constraints for a first constellation of non-geostationary satellites transmitting towards a terrestrial station with respect to a second constellation of non-geostationary satellites linked with the station, the constraints comprising a maximum transmission power of the satellites of the first constellation, the method comprising: determining triplets of limit values (&#x3b8;, &#x3d5;, I/N) of two angles (&#x3b8;, &#x3d5;) and of an interference-to-noise ratio (I/N), the angles (&#x3b8;, &#x3d5;) defining a position of a satellite of the first constellation relative to the station and to a satellite of the second constellation and the interference-to-noise ratio being the ratio between interferences transmitted by the first constellation on a link between the station and the satellite of the second constellation and the noise (N) of the link, the determination of the triplets being performed so that a distribution of signal-to-noise and interference ratios (R) aggregated over a time interval is greater than a reference distribution; determining at least the maximum transmission power of at least one satellite of the first constellation from the triplets.

Method for determining constraints of a non-geostationary system with respect to another non-geostationary system

A method for determining a maximum transmission power (Pmax, PR, PO) of a non-geostationary satellite (NGSO, NGSO) in the direction of a ground station (GSO_SOL), includes the steps of: determining the minimum value of a topocentric angle (&#x3b1;NGSO, &#x3b1;NGSO), formed between the non-geostationary satellite, the ground station and a point of the geostationary arc (ARC_GSO); comparing, in terms of absolute value, the minimum value of the topocentric angle with at least two threshold values (&#x3b1;r, &#x3b1;o), such that: if it is less than the first threshold (&#x3b1;r), defining the maximum transmission power at a first value (PR), if it is between the first threshold and the second threshold (&#x3b1;o), defining the maximum transmission power at a second value (PO), greater than the first value, or if it is greater than the second threshold, defining the maximum power at a third value (Pmax), greater than the second value; the maximum transmission power values and the thresholds being determined so as to minimize the deviation between a distribution of the power levels received by the station (GSO_SOL) and added over a time interval and a reference distribution (REF), greater than the distribution of the power levels.

Method for determining a maximum transmission power of a non-geostationary satellite

A method for determining operational constraints for a first constellation of non-geostationary satellites (CONS_I) transmitting towards a terrestrial station (SV) with respect to a second constellation of non-geostationary satellites (CONS_V) linked with the station, the constraints comprising a maximum transmission power of the satellites of the first constellation, the method includes determining triplets of limit values (&#x3b8;, &#x3c6;, I/N) of two angles (&#x3b8;, &#x3c6;) and of an interference-to-noise ratio (I/N), the angles (&#x3b8;, &#x3c6;) defining a position of a satellite (NGSO_I) of the first constellation relative to the station and to a satellite (NGSO_V) of the second constellation and the interference-to-noise ratio being the ratio between interferences (I) transmitted by the first constellation on a link between the station and the satellite of the second constellation and the noise (N) of the link, the determination of the triplets being performed so that a distribution of signal-to-noise and interference ratios (R) aggregated over a time interval is greater than a reference distribution (REF); determining at least the maximum transmission power of at least one satellite of the first constellation from the triplets.

A method is provided for improving the acquisition of a data set transmitted repeatedly in a difficult environment, which is particularly appropriate to satellite radionavigation systems. The main characteristic of the method is to provide 'contextual' aid relating to the transmitted data by indicating the nature and the possible updating of these data so that the receiver can accumulate the energy when the data are repeated in an identical manner. These aid data being short, it is possible to obtain good quality of reception and protection of this aid by virtue of its longer coding than that of the data.

Method for improving the acquisition of a data set transmitted repeatedly in a difficult environment

A method and a system calculates the low probability events for the evaluation of the precision performance of a satellite navigation system, and makes it possible to certify the precision performance of a satellite navigation system for high levels of requirement by modelling events of low probability on the basis of the implementation of the theory of extreme values conjointly with the use of a chart for evaluating precision performance.

Method and system of calculation for the evaluation of the precision performance of a satellite navigation system

A method and a system verifies the precision performance of a satellite navigation system that can certify compliance with a level of precision whatever the observation conditions, notably as regards satellite geometry, and is a performance verification tool for the design, verification and qualification of a satellite navigation system.

Method and system for verifying the precision performance of a satellite navigation system

The invention relates to a network making it possible to calculate and provide ionospheric corrections to the users of a satellite navigation system, wherein the network also comprises: an aeronautical segment comprising an aeronautical user segment composed of a plurality of aircraft each one having an on-board RF receiver capable of measuring delays of the navigation signals transmitted by the satellites and an aeronautical data communication means between the plurality of aircraft and the ground segment in order to transmit said measurements of delays to the ground segment, and means, at the level of the ground segment, of receiving measurements of delays used for the calculation of the grid, the measurements of delays coming from the plurality of aircraft and from the plurality of ground stations.

Network and method for calculating ionosphere corrections

The invention relates to a calculation device providing means for estimating an indication of integrity of a satellite navigation system, including a means for estimating in real time, by measuring data calculated by the navigation system, an indication of integrity of the system with respect to very low-probability location errors, the device including a means for receiving data calculated by the location system, a means for estimating a model of distribution of location errors, a means for estimating parameters characterizing the distribution model, a calculation means applying the extreme values theory as a function of the parameters characterizing the distribution model enabling the modeling of the distribution of very low-probability location errors, a means for estimating in real time an indication of integrity for very low-probability location errors, and a means for transmitting in real time an indication of integrity.

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Balma, France

Jean-Christophe Levy