Article,
Design of a Reconfigurable Low-Complexity Tracking Loop for Galileo Signals
Proc. of IEEE ISSSTA, Sydney, Australia, (2004)
Abstract
The increased use of digital technology in communications is resulting
in more functions of contemporary radio systems that are being implemented
using a Software-Defined-Radio (SDR) approach 1. The growing interest
towards navigation applications, the advent of the European Navigation
System Galileo and the new generation GPS, make the SDR approach
an interesting perspective to develop a software reconfigurable receiver
for positioning applications. Even if the present technology does
not allow to totally implement a personal communications receiver,
navigation terminals demand for less stringent processing and can
be almost completely designed with software defined radio techniques.
One of the basic function of a navigation receiver is the signal
tracking of a CDMA modulated Signal-In-Space (SIS) broadcast by the
satellites constellation (GPS or the future European Galileo). Better
is the sequences alignment performed in this stage, better is the
pseudorange measurements used for the user position triangulation.
This paper discusses the digital implementation of a delay-lock-loop
(DLL) tailored for navigation application where a fine synchronization
is required, with the aim of keeping as small as possible the system
complexity requirement for a software-defined implementation.
