Thales

Sextant Avionique

Yves Clauzel

Nicolas Martin

Jean-Michel Perre

Pierre-Yves Dumas

Christian Jaeger

This determination method for determining a wrong synchronization including the steps of determining an ad hoc correlator corresponding to the value of correlation between the received signal and the local signal, and determining N additional correlators corresponding to the values of correlation between the received signal and an offset signal, each offset signal including a spreading code that is offset in relation to the local spreading code, and determining a value for the amount of inconsistency between the frequency of the local carrier wave and the frequency of the local spreading code; if the value of inconsistency is higher than a predetermined threshold value of inconsistency, determining a wrong synchronization; otherwise, determining an indicator of wrong synchronization as a function of the correlators determined, comparing the indicator of wrong synchronization with at least one threshold value, determining a wrong synchronization based on the result of the comparison.

Method for determining a wrong synchronization of a receiver with a satellite, associated module and computer program product

A system for receiving a radionavigation signal, notably in a jammed medium, emitted by a satellite of a satellite positioning system, includes: at least one first multi-correlator and at least one second multi-correlator disposed in parallel and operating respectively at a frequency; filtering means, disposed upstream of said multi-correlators; a delay line, disposed on the branch, between the filtering means and the second multi-correlator; means for sub-sampling at the frequency adapted for sub-sampling the signal transmitted directly and by branching with delay by the filtering means; and demodulation means eliminating the Doppler effect, disposed between the sub-sampling means and the first and second multi-correlators.

System and method for multi-correlation with modulation-adapted filter for the fast acquisition and the tracking of a radio navigation signal in the presence of jamming

A receiver of a digital signal equipped with an N-state weighted-decision trellis Viterbi decoder, the signal received including a series of symbols, is provided. The receiver comprises a programmable logic circuit that includes a source memory A and a destination memory B each comprising N rows and M+L columns respectively allocated to M fixed fields for describing the trellis, and to L variable fields, and an operator able to calculate the variable fields of a memory as a function of the fixed fields of the said memory, of the symbols received and of the variable fields of the other memory and able to reverse the role of the source memory and destination memory.

Receiver equipped with a trellis viterbi decoder

The field of the invention is that of the reception of a radionavigation signal originating from a satellite positioning system such as the GPS system. The present invention concerns a method for calculating correlations between a first sequence and a second sequence, said first sequence and said second sequence having a duration D, the first sequence being extracted from a digital signal comprising a code, said code comprising elementary time divisions, called chips, of mean duration D, said chips being synchronized with pulses delivered by an NCO oscillator at the mean frequency 2/D, the second sequence resulting from a sampling at a frequency Fof an analog signal, the frequency Fbeing greater than 2/D. According to the invention, the method comprises a step of aggregating samples of the second sequence, over consecutive integration intervals of duration equal on average to D/2, starting at each pulse of the NCO oscillator, so as to determine results of elementary aggregates.

Method and device for fast correlation calculation

A processor system and communications processor between a plurality of sub-components is described. To each sub-component of equipment is associated at least one logical channel that is associated with at least one physical channel. Each sub-component addressing only the logical channels that it is associated with, and the various physical channels being time multiplexed on an internal communications bus (BCI). The system has particular application to systems of radio-communication or of embarked navigation.

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Montelimar, France

Yves Clauzel