Abstract: An iterative method for detecting is provided, with at least one receiver satellite in orbit, a target possessing reflective properties that are different from those of the area in which the target is found, by GNSS reflectometry, wherein the reflected GNSS signals are received by an active antenna of the receiver satellite comprising a plurality of antenna elements, the method comprising a step of determining assumed positions of the target, for which positions it is desired to detect the target, and, forming beams and tracking GNSS signals in accordance with these assumptions.

Abstract: An iterative method for detecting is provided, with at least one receiver satellite in orbit, a target possessing reflective properties that are different from those of the area in which the target is found, by GNSS reflectometry, wherein the reflected GNSS signals are received by an active antenna of the receiver satellite comprising a plurality of antenna elements, the method comprising a step of determining assumed positions of the target, for which positions it is desired to detect the target, and, forming beams and tracking GNSS signals in accordance with these assumptions.

Abstract: A satellite communications network, methods of sending, receiving and repetition, and the associated items of equipment wherein the transmission of a signal between a sending station and a receiving station is relayed by a plurality of satellites visible in common to both these stations are provided. The position of the sending station, the receiving station and the satellites relaying the signal is known by at least one of these items of equipment, which is further configured to separate the signals relayed by the satellites, and to compute, for each of the signals, at least one shift introduced by the propagation of the signal, on the basis of the position of the sending station, of the receiving station, and of the satellite by which it is transmitted, and then to apply the inverse shifts to the signal.

Abstract: In the field of satellite geolocation, a geopositioning method with a trust index is implemented by a geopositioning terminal. According to the method, the positioning of the terminal is estimated by geopositioning satellites and the trust index is provided by comparison with at least one pseudo-distance measurement recorded by at least one additional geopositioning satellite, which is different from those used to compute the position of the terminal.

Abstract: A method is implemented by computer for the management of a convoy comprising at least two vehicles, each of the at least two vehicles comprising satellite positioning means and vehicle-to-vehicle communication means, the method comprising the determination of the relative positioning of the vehicles, the determination comprising the measurement of the propagation time of a signal between vehicles by the communication means, the clocks associated with the communication means being synchronized via satellite positioning means at a reference clock time. Developments comprise the communication between the vehicles of various data (e.g. measurement uncertainties, signal-to-noise ratios, residual values), the determination of absolute locations, the use of an SBAS-type system, the use of differential GPS, the use of Doppler measurements for the turns or even the exclusion of a failing satellite. A computer program product and associated systems are described.

Abstract: A satellite communications network, methods of sending, receiving and repetition, and the associated items of equipment wherein the transmission of a signal between a sending station and a receiving station is relayed by a plurality of satellites visible in common to both these stations are provided. The position of the sending station, the receiving station and the satellites relaying the signal is known by at least one of these items of equipment, which is further configured to separate the signals relayed by the satellites, and to compute, for each of the signals, at least one shift introduced by the propagation of the signal, on the basis of the position of the sending station, of the receiving station, and of the satellite by which it is transmitted, and then to apply the inverse shifts to the signal.

Abstract: A method includes estimating the position of the moving object on the basis of the reception of navigation signals emitted by a constellation of satellites, the navigation signals being modulated by a code and the receiver comprising a local replica of the code. The determination of the confidence indicator consists in estimating a speed of displacement of the receiver over an identified trajectory segment, deducing therefrom a Doppler delay function corresponding to the motion of the receiver, in correcting the auto-correlation function of the GNSS navigation signal received from each satellite of the constellation by means of the delay function, in comparing the corrected auto-correlation function with a theoretical auto-correlation function by applying a quadratic criterion corresponding to the confidence indicator.

Abstract: In the field of active phase-control antennas, a method is provided for calibrating the phase center of an active antenna including a plurality of sub-elements able to receive a useful signal emitted by a satellite, the calibration being defined as a function of the reception characteristics of a reference signal at the level of each sub-element, the reference signal being emitted by the same satellite on a frequency band substantially equal to the frequency band of the useful signal and whose theoretical reception characteristics are known.

Abstract: A method is provided for propagating messages in a communication network to a satellite network, the communication network being made up of a set of users and the satellite network comprising at least one satellite, the set of users comprising a sender and a recipient, said recipient being intended to send to the satellite network an initial message originating from the sender, at least one satellite of the satellite network being visible to said recipient, in which each user determines a number of intermediaries needed to reach the recipient and periodically sends a message comprising said number of intermediaries needed to reach the recipient, and said initial message being sent by the sender to the visible user having the lowest possible number of necessary intermediaries, called optimal intermediary, said optimal intermediary becoming, in turn, sender and sending the initial message, the operation being repeated until the recipient is reached.

Abstract: A method is provided for demodulating a signal carrying a message transmitted by a terrestrial beacon, executed by a system comprising a constellation of satellites suitable for detecting said signal and for repeating it towards receiving stations on the ground, and an analysis module suitable for receiving signals from said stations. Each receiving station transmits the signals that it receives from the satellite to the analysis module, said module realigning said signals in frequency and/or in time relative to one another, combining the realigned signals to generate a synthetic signal having an enhanced signal-to-noise ratio, and determining the content of said message and/or the modulation parameters of said synthetic signal. The method applies notably to the accurate and reliable location of distress beacons by a satellite system.

Abstract: A method includes estimating a position of a receiver, aboard a moving object, on the basis of the navigation signals emitted by satellites received by an antenna in an antenna array placed on the moving object, and using a three-dimensional geographical map to deduce, geometrically, on the basis of the position of the receiver and of a ray casting starting from the receiver, the number of paths reflected on walls of buildings present in a scene corresponding to an environment surrounding the receiver. The determined number of reflected paths is used to initialize an algorithm for estimating angles of arrival of multi-paths to deduce therefrom angles of arrival of the paths reflected on the walls before reaching the receiver. Optionally, the method can comprise making it possible to bound the distance information error due to a multi-path to render the estimation of direction of arrival of the signals more efficacious.

Abstract: A method is implemented by computer for the management of a convoy comprising at least two vehicles, each of the at least two vehicles comprising satellite positioning means and vehicle-to-vehicle communication means, the method comprising the determination of the relative positioning of the vehicles, the determination comprising the measurement of the propagation time of a signal between vehicles by the communication means, the clocks associated with the communication means being synchronized via satellite positioning means at a reference clock time. Developments comprise the communication between the vehicles of various data (e.g. measurement uncertainties, signal-to-noise ratios, residual values), the determination of absolute locations, the use of an SBAS-type system, the use of differential GPS, the use of Doppler measurements for the turns or even the exclusion of a failing satellite. A computer program product and associated systems are described.

Abstract: In the field of satellite geolocation, a geopositioning method with a trust index is implemented by a geopositioning terminal. According to the method, the positioning of the terminal is estimated by geopositioning satellites and the trust index is provided by comparison with at least one pseudo-distance measurement recorded by at least one additional geopositioning satellite, which is different from those used to compute the position of the terminal.

Abstract: A method for the geolocation of a device transmitting a signal containing at least one message to a plurality of relay satellites in a medium earth orbit, visible from said device, receiving said message and transmitting it to processing means, comprises at least the following steps: determination of the times of reception of the message by the relay satellites; determination of the pseudo-distances between the device and the relay satellites; searching for and acquiring a minimum number N of satellite radio navigation signals; determination of the time lags between the transmission of the radio navigation signals and their reception by the said device; broadcasting by the device of these time lags in the message; and, determination of the position of the device from at least the pseudo-distances, from the time lags and from the positioning coordinates of the relay satellites and of the radio navigation satellites.

Abstract: A method for detecting the distortion of a GNSS signal transmitted by at least one GNSS satellite and received by at least one GNSS receiver is disclosed, where the distortion is caused by a GNSS signal generation defect. Initially, at least one autoregressive parametric model of the GNSS signal is determined at the output of a correlation stage of the GNSS receiver. Next, at least one linear prediction error e(n) between the output signal of the correlation stage and the autoregressive parametric model is computed. The linear prediction error is compared to a detection threshold and the distortion of the transmitted GNSS signal is decided when the linear prediction error exceeds the detection threshold.

Abstract: A system for augmenting the availability and performance of a satellite geolocation system uses a behavior model of at least one of the satellites of the satellite geolocation system. The behavior model includes parameters with which to augment the nominal operating range of the geolocation system. The behavior model also includes an indicator of the deviation between the behavior model and the real behavior of the at least one satellite, to enable a receiver to continue to use at least one satellite to determine the position of the receiver using the behavior model outside the nominal operating range of the satellite geolocation system. The parameters of the behavior model include at least a model of distortion of code chips transmitted by the at least one satellite to the receiver, or a model of distortion of the phase of the signal transmitted by the at least one satellite to the receiver.

Abstract: A method for optimizing an acquisition phase of a spread-spectrum signal by a mobile receiver includes searching for a trend path having the maximum energy for different frequency assumptions and among all the positive trend paths of frequencies between initial and final instants marking the beginning and the end of a coherent signal integration.

Abstract: A method is provided for propagating messages in a communication network to a satellite network, the communication network being made up of a set of users and the satellite network comprising at least one satellite, the set of users comprising a sender and a recipient, said recipient being intended to send to the satellite network an initial message originating from the sender, at least one satellite of the satellite network being visible to said recipient, in which each user determines a number of intermediaries needed to reach the recipient and periodically sends a message comprising said number of intermediaries needed to reach the recipient, and said initial message being sent by the sender to the visible user having the lowest possible number of necessary intermediaries, called optimal intermediary, said optimal intermediary becoming, in turn, sender and sending the initial message, the operation being repeated until the recipient is reached.

Abstract: A system for positioning an object provided with a receiver, which includes a set of pseudolites transmitting positioning signals and distributed in a constrained area, assistance means capable of communicating with said receiver and calculating a position of the object, and a server capable of dynamically configuring the set of pseudolites, the pseudolites each further having a spreading code corresponding to that of a satellite belonging to a satellite constellation in a satellite navigation system, the dynamic configuration of the pseudolites by the server is such that the spreading codes of said pseudolites correspond to spreading codes of satellites of the satellite constellation not visible to the receiver of the object, wherein the assistance means is configured to communicate to said receiver a list of spreading codes meant to be those of the satellites visible to said receiver but actually corresponds to the spreading codes of the set of pseudolites so as to deceive the receiver that can acquire the

Abstract: Method of geolocation employing hybridization of a satellite navigation system and a data collection system. The method minimizes processing time by the means equipping the objects to be geolocated, given the processing effected in “masked time” by remote equipment, typically ground stations of the data collection system. To this end, the method necessitates only acquisition of the code phase of the positioning information coming from the satellite navigation system.