Thales

Centre National Detudes Spatiales

Damien Kubrak

Michel Monnerat

Lionel Ries

Thibaud Calmettes

Damien Serant

Géraldine Artaud

A method for detecting anomalies on satellite navigation signals consists in extracting the code error values delivered at the output of the N code discriminators, and comparing the extracted code error values with a same first threshold value corresponding to an acceptable maximum code error value and assigning a confidence index to each navigation signal received on each reception channel i, the confidence index depending on the result of the comparison carried out on the code error values.

Method and system for detecting anomalies on satellite navigation signals and hybridization system comprising such a detection system

A positioning system comprises a set of pseudolites distributed in a confined area, said pseudolites transmitting positioning signals characterized by their time desynchronization and their apparent Doppler frequency, said time desynchronization and/or said apparent Doppler frequency of the positioning signals transmitted by the pseudolites being configured so that there is no ambiguity concerning the location of the correlation peaks P, P, P, P, Pin the matrix of ambiguities defined by the delay and the apparent Doppler frequency of the positioning signals acquired by the receiver.

Pseudolite positioning system

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.

Method for detecting the distortion of a GNSS signal

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 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.

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Toulouse, France

Damien Kubrak