Thales

Centre National Detudes Spatiales

Thibaud Calmettes

Michel Monnerat

Lionel Ries

Damien Serant

Nicolas Chuberre

Erwan Corbel

Damien Kubrak

Guillaume Carrie

Cyril Michel

Rémi Challamel

Benoît Vautherin

Jérémie Giraud

Arnaud Barthere

Yoan Gregoire

Philippe Karouby

Fabien Rozo-Quillere

Christelle Iliopoulos

Laurent Combelles

Pauline Martin

Phillippe Karouby

Remi Challamel

Jeremie Giraud

Nicolas François Jean Chuberre

Erwan Corbell

Arnaud Barthère

A method for determining a phase bias in the signal transmitted by at least one of the radiating elements of an active antenna on the ground emitting signals into space using a space-division multiple access SDMA method, implementing a step, for each reference receiver, of comparing, to a threshold, the difference between the value of a measurement of the power received by each reference receiver and the sum, out of the radiating elements of the subset beamforming in the direction of the reference receiver, of the differences between the equivalent isotropically radiated power in the direction of the reference receiver and the free-space path loss of each radiating element of the subset.

Method for determining a phase bias in the signal transmitted by at least one of the radiating elements of an active antenna, and associated device

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.

Method for detecting a target by GNSS reflectometry and associated system

A method is provided for transmitting additional information on communication or navigation signals with spectrum spreading, the additional information being coded by a value of intentional quantized degradation of the correlation of the spreading code, the degradation being coded on the spreading code by modifying at least one chip.

Method for transmitting additional information on transmission signals with spectrum spreading and associated system

A method of following a transfer orbit or a phase of orbital placement of a continuous-thrust space vehicle comprises the following steps: a) tracking at least one GNSS signal and using it to determine at least one pseudorange between the space vehicle and one or more GNSS satellites transmitting the signal; b) using an estimation model to jointly estimate a set of state parameters of the space vehicle comprising a plurality of position parameters, a plurality of velocity parameters and at least one thrust error parameter characterizing a discrepancy between an actual thrust force of the space vehicle and a nominal thrust force by taking the pseudorange or pseudoranges as input datum of the estimation model. An apparatus for the implementation of such a method is also provided.

Method of following a transfer orbit or a phase of orbital placement of a space vehicle, in particular an electric propulsion vehicle, and apparatus for the implementation of such a method

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.

Solution with massive spatial distributing for telecom constellation

An integrated radio communication system with ordered hierarchical cellular coverage comprises a first system and a second system, the coverage of the second system covered by the coverage of the first system, and a set of dual-mode terminals that can selectively use the first system or the second system. The first and second systems are configured to simultaneously share a common portion Bc of a first band Bof frequencies respectively on a first uplink and a second uplink, and respectively manage first transmission resources and corresponding second transmission resources. The second radio communication system of lower level Nis free to manage its second transmission resources without any coordination constraint with respect to the first system of higher level Nwhereas the first system of higher level is configured to not disturb the second system in the common frequency band portion. The first system is configured to transmit data packets on a first uplink random access contention channel and to manage its first resources optimally in terms of transmission capacity of the channel as a function of the measurement of the occupancy of the second radio resources currently used by the second system and of the first resources currently used by the first system.

Integrated radio communications system using an ordered hierarchical cellular coverage

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.

Driving vehicles in convoy

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.

Method for calibrating an active antenna

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.

Method for propagating messages in a communication network to a satellite network

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.

Method for the coordinated processing of signals transmitted by beacons

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.

Method and system for the geolocation of a radio beacon in a search and rescue system

A method for demodulating time-multiplexed signals able to mutually collide, in particular in the case of an AIS (Automatic Identification System), being a communications system between ships allows collisions between these ships to be limited and allows the maritime traffic in view from the coasts to be monitored thanks to coastal stations that listen to the communications. When these colliding signals are sufficiently 'distinct' (in frequency, in power or in time), algorithms exist for discriminating between them. The demodulator offers the possibility of demodulating two colliding signals, whose collision parameters (difference in frequency, in power or their non-synchronization) are sufficiently small to make them virtually inaccessible otherwise. The method and equipment allow the satellite AIS system to utilize cases of signal collisions that were hitherto detrimental in order to improve the overall performance.

Method for demodulating signals from a multi-access system able to collide and equipment for implementing same

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.

Satellite based augmentation system

A method of recovering a useful signal received by a satellite includes a step of reception by the satellite of a composite signal comprising said useful signal and collision signals, all of these signals being received simultaneously by the satellite, interfering with each other, and respectively being transmitted by transmitters. The method includes the steps of: direct reception, by at least one station of a terrestrial network, of signals corresponding to at least a non-zero portion of said collision signals and referred to as collected collision signals; for each collected collision signal, estimation, by a processing unit connected to the terrestrial network and to the satellite, of the collision signal received by the satellite as a function of (i) the collected collision signal received directly by the terrestrial station, (ii) the position of the transmitter at the time of transmission of this collision signal, and (iii) the position of the satellite during the reception of the composite signal; and extraction of the collected and estimated collision signals, from the composite signal, in order to allow recovery of the useful signal.

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Toulouse, France

Thibaud Calmettes