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 system for receiving a radionavigation signal, notably in a jammed medium, emitted by a satellite of a satellite positioning system, the system comprising:

• at least one first multi-correlator and at least one second multi-correlator disposed in parallel and operating respectively at a frequency Fcode generated by a numerically controlled oscillator, the offset between the sequences of correlations of two successive correlators of one and the same multi-correlator being equal to an elementary duration Tc of the spreading code, during which the value of the spreading code is constant;
• filtering means, disposed upstream of said multi-correlators, of impulse response substantially equal to the waveform of the signal emitted by the satellite making it possible to perform an aggregate of the samples of the signal received, operating at the sampling frequency Fe of the signal emitted by the satellite for the set of reception channels, and delivering as output a filtered signal destined for the first multi-correlator and destined for the second multi-correlator by branching;
• a delay line, disposed on the branch, between said filtering means and said second multi-correlator, comprising a set of delay modules with controlled individual activation/deactivation, disposed in series, a delay module being adapted for causing a delay of a sampling period of the signal emitted by the satellite equal to the inverse of the sampling frequency Fe;
• means for sub-sampling at the frequency Fcode and adapted for sub-sampling the signal transmitted directly and by branching with delay by said filtering means;
• and
• demodulation means for eliminating the Doppler effect, disposed between said sub-sampling means and said first and second multi-correlators.