Phase lock loop false lock avoidance in presence of global navigation satellite system signal

This paper deals with the problem of false carrier phase lock when a digital PLL is inserted in the channel chain of a digital GNSS receiver. A bad initialization of such a loop on the basis of the acquisition estimate might lead to an erroneous false lock in the carrier frequency and phase. Clearly this false lock affects in a dramatically way the functioning of the receiver. The solution to this problem might be performed both on the acquisition or tracking stages. In this paper the problem of the false lock as well as a solution to it suitable for a software implementation will be presented.