Abstract: In the field of satellite global navigation, a method is provided for estimating the level of error in global navigation satellite measurements and for ensuring the reliability of these estimations, implemented by a global navigation device in which local errors are detected by said global navigation device and errors associated with the satellites are detected by a ground segment.

Abstract: A system and method are provided for determining a distribution of a position error of a receiver of localization signals, the signals being sent by at least one satellite. The system includes the receiver, one position of which is known as first position and is affected by an error, known as first error, having a distribution, known as first distribution, a first device for determining positions of the satellite(s), known as second positions, a device for transmitting the second position of the first determination device to the receiver, and the first distribution is defined by at least one first cumulant, of higher-than-second order.

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: In the field of satellite global navigation, a method is provided for estimating the level of error in global navigation satellite measurements and for ensuring the reliability of these estimations, implemented by a global navigation device in which local errors are detected by said global navigation device and errors associated with the satellites are detected by a ground segment.

Abstract: A system and method are provided for determining a distribution of a position error of a receiver of localization signals, the signals being sent by at least one satellite. The system includes the receiver, one position of which is known as first position and is affected by an error, known as first error, having a distribution, known as first distribution, a first device for determining positions of the satellite(s), known as second positions, a device for transmitting the second position of the first determination device to the receiver, and the first distribution is defined by at least one first cumulant, of higher-than-second order.

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: The present invention relates to a method for protecting a radionavigation receiver user in relation to aberrant pseudo-range measurements. In the method, a measurement error is detected by a statistical estimation scheme based on calculating the residuals of the measurements.

Abstract: A method for correcting the prediction of values of signal with time variation, in particular for navigation messages sent by the global satellite navigation systems, includes the following steps for the correction of the predictions of a parameter included in a received signal and varying in time: estimation of the prediction error based on a first batch of values estimated during a determined time period by comparing these values to the values previously predicted for the same determined time period, analysis of the predicted time-oriented series of prediction errors by a method for processing the signal and isolating the contributions of the systematic effects, and extrapolation of the behavior of the contributions of the systematic effects during the time period concerned and correction of the predictions using the duly extrapolated values.

Abstract: A system for positioning an object in a constrained zone, including: a set of pseudolites distributed in the constrained zone and each presenting a spreading code corresponding to the spreading code of a satellite belonging to a constellation of satellites of a satellite navigation system, the constellation of satellites including a first set of satellites and a second set of satellites of disjoint visibility, and a receiver on the object to be localized, the pseudolites being distributed in the constrained zone such that, at any point of the constrained zone, the receiver can acquire the positioning signals of at least two pseudolites presenting spreading codes corresponding to a satellite of the first set, and to a satellite of the second set, such that the receiver detects the impossibility of the acquired signals being transmitted by satellites of the constellation of satellites and determines the acquired signals were transmitted by pseudolites.

Abstract: A method for correcting position estimations is provided, an enhanced position Xhuber being determined by application of a robust estimation algorithm using N measurements of pseudo-distances ?i corresponding to the distance measured between a navigation receiver and N satellites and an estimation Xprim of the position of said receiver made by said receiver. The method comprises: determining normed residue values ?rihuber from the residues ??ihuber of pseudo-distances from the measurements ?i, determining ? subsets, a subset comprising N-k normed residue values ?rihuber, k being an integer strictly greater than 1, selecting the subset SEO with the smallest standard deviation ?SEO, selecting non-aberrant measurements, a measurement being selected if the difference between the normed residues ?rihuber and the mean ?SGO of the normed residues of the subset SEO is less than a predetermined threshold value T1, and determining a corrected estimation Xcln of the position from the selected measurements.

Abstract: A method for correcting the prediction of values of signal with time variation, in particular for navigation messages sent by the global satellite navigation systems, includes the following steps for the correction of the predictions of a parameter included in a received signal and varying in time: estimation of the prediction error based on a first batch of values estimated during a determined time period by comparing these values to the values previously predicted for the same determined time period, analysis of the predicted time-oriented series of prediction errors by a method for processing the signal and isolating the contributions of the systematic effects, and extrapolation of the behavior of the contributions of the systematic effects during the time period concerned and correction of the predictions using the duly extrapolated values.

Abstract: The present invention relates to a method for protecting a radionavigation receiver user in relation to aberrant pseudo-range measurements. In the method, a measurement error is detected by a statistical estimation scheme based on calculating the residuals of the measurements. This method makes it possible, in particular, in a manner which is autonomous of any ground segment (therefore implementing a RAIM functionality) to boost the performance of an off-the-shelf receiver (termed “primary”) without any integrity function, to detect possible errors contaminating measurements on input to the calculation of the position, through the use of a robust estimation statistical algorithm, that is to say one truly unaffected by measurement errors, and implementing a dynamic criterion, and to calculate a robust correction for the position provided by the primary receiver by excluding such an error if it is detected.

Abstract: A device dedicated to generating integrity messages relating to at least one satellite navigation system including a set of satellite surveillance stations and to be sent to navigation receivers. The device includes a processor responsible for determining at chosen times the stations that are active (i.e. nominal or degraded) for each system concerned and, after each such determination, for generating an integrity message including at least primary data representative of the active (i.e. nominal or degraded) stations. The processor is also responsible, each time it detects that at least one station has become degraded or inactive between two successive chosen times, for generating an integrity alert message including at least primary data representative of each station that has become degraded or inactive.

Abstract: This invention relates to a method for determining the position of satellites in a satellite navigation system. The method uses satellite position data (42) external to the navigation system and referenced in a coordinate system related to the earth, these data being converted (33) into a Galilean coordinate system to calculate (34) satellite orbits, predictions (43) of satellite positions being determined from orbits converted into the Galilean coordinate system. Subsequently, two solutions are possible to transfer data into a coordinate system related to the earth. In a first solution, coordinates are transferred in a central manner into the coordinate system related to the earth, and navigation data are then prepared and transmitted in advance to users. In a second solution, coordinates related to the Galilean coordinate system are transmitted to users directly and the transfer into the coordinate system related to the earth is made on the user's equipment.

Abstract: A device is dedicated to generating integrity messages relating to at least one satellite navigation system including a set of satellite surveillance stations and to be sent to navigation receivers. The device comprises processor means responsible for determining at chosen times the stations that are active (i.e. nominal or degraded) for each system concerned and, after each such determination, for generating an integrity message including at least primary data representative of the active (i.e. nominal or degraded) stations. The processor means are also responsible, each time they detect that at least one station has become degraded or inactive between two successive chosen times, for generating an integrity alert message including at least primary data representative of each station that has become degraded or inactive.