Adaptive noise bandwidth based carrier tracking loop method in navigation receivers

A novel method based on adaptive noise bandwidth in carrier tracking loop of navigation receivers is given to improve carrier tracking performance on loop converging speed and accuracy. The relationship between noise bandwidth changes and frequency offset of the loop is analyzed, as well as variations of coherent accumulation value in the in-phase prompt code branch (called I_F) at different track stages. On this basis, the normalized mean squared deviation (NMSD) of coherent accumulation value is defined and it can be used as the dependent variable for the change of the noise bandwidth. Real satellite signal simulation shows that the proposed scheme well balances dynamic stress and loop noise so that the carrier loop can continuously keep lock on the incoming signal.