Method for the acquisition of radionavigation signals carrying spreading code with a quasi-infinite period

摘要

A method for the acquisition of a radionavigation signal carrying a spreading code with a quasi-infinite period, where the signal is sampled in baseband on a delay line and correlated with a local spreading code replica, the sampled signal is shifted on the delay line from one correlation to the other, where in order to correlate the signal with the local replica of the code, a plurality of sequences of the spreading code are generated, the code sequences being of the same duration, equal to the duration of the signal sampled on the delay line, and associated with the consecutive time ranges in the temporal alignment search space, where each of the code sequences is correlated with the signal sampled in a respective correlation operation, the correlation operations being executed in parallel for the different sequences of code.

主权项

1. A method for acquiring a radionavigation signal carrying a spreading code with a period that is at least 10 times longer than a correlation time, comprising:
obtaining a baseband radionavigation signal based on converting the radionavigation signal to an intermediate frequency radionavigation signal and sampling and converting the intermediate frequency radionavigation signal to the baseband radionavigation signal on a delay line, and correlating the baseband radionavigation signal with a local spreading code replica so as to identify a time delay between the spreading code of the baseband radionavigation signal and the local spreading code replica in a temporal alignment search space; wherein, in order to correlate the baseband radionavigation signal with the local spreading code replica, m spreading code sequences are generated where m is greater than 1, each of said m spreading code sequences being of a same duration, equal to a duration of the baseband radionavigation signal, and said m spreading code sequences are associated with consecutive m time hypotheses spaced by the correlation time in the temporal alignment search space, each of said m spreading code sequences is correlated with the baseband radionavigation signal in a respective correlation operation among m correlation operations, said m correlation operations being executed in parallel for each of said m spreading code sequences associated with the m time hypotheses spaced by the correlation time.