Modeling and simulation on GNSS vector tracking loop based on extended kalman filter

Considering a limited public information about analysis of GNSS vector tracking algorithm control process, a vector delay/frequency lock loop (VDFLL) tracking model is established, and a derivation on the model's linearization process is proposed. The sequential control logic of vector tracking algorithmis analyzed. For the fact that VDFLL cannot lock the carrier phase, a message demodulation mode based on series phase-locked loop (PLL) is put forward. And a vector VDFLL model is implemented on the platform of a software receiver. The simulation results indicate that the controlling model not only can output correct and optimal estimate for receiver state information, but also has an excellentdynamic tracking performance.