Patent ID: 8094697

Claim:
A method for demodulation of radio navigation signals that are transmitted in spread spectrum and that comprise (i) a data channel that is modulated by a navigation message and (ii) a pilot channel that is not modulated by the navigation message, the data channel and the pilot channel being combined into one multiplexing scheme in order to modulate a carrier, the method comprising: determining Doppler velocity aid using a discrete navigation system that does not rely only on the radio navigation signals, wherein the discrete navigation system combines information from the radio navigation signals with other information that is independent of the radio navigation signals; generating a despread data signal by subjecting the signals of the pilot and data channels to despreading processing; and demodulating the despread data signal in order to obtain the navigation message, wherein the demodulation of the despread data signal used to obtain the navigation message is performed with the aid of the carrier obtained from the despreading processing of the pilot channel, wherein the despreading processing is performed by code tracking processing combined with at least one of carrier phase tracking processing or carrier frequency tracking processing, wherein the code tracking processing is performed using a delay-lock loop (DLL) or an open-loop device of zero order, and wherein the carrier tracking processing is performed using an open-loop filter of first or second order.