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

In this paper we analyse the operation of a fully digital Phase Lock Loop (PLL) in a false lock regime, using real data. The issue has been noticed while we were testing performance of our software receiver in a moving user scenario. While the phenomenon of false lock has been described in other papers about PLLs, our intent is to describe a practical, and in our opinion interesting, issue we encountered and how we got over it.

Sistema di posizionamento geo-spaziale cooperativo operante con sistemi di navigazione globale satellitare e reti di telecomunicazione wireless, relativo procedimento e apparato di posizionamento geo-spaziale

Is it possible to define a fully digital state model for Kalman filtering?

A software receiver adaptive phase lock loop method

The aim of this paper is to introduce a new and relatively simple algorithm which is capable to tune the parameters of the loop filter in a phase lock loop, like the one that can be found in a global navigation satellite system receiver. The parameters are chosen while the system is running, in order to make the bandwidth of the filter adaptive with respect to the signal dynamic and strength. A wider bandwidth is obtained to make the filter more reactive when searching the carrier, while the bandwidth gets narrower when the system is in the tracking state, in order to cut off as much noise as possible. The algorithm is based on the observation of the estimated variance of the phase lock loo…