Simulation & Verification of New Architectures for Galileo Navigation Signal Demodulation

S. Fischer, S. Berberich, J. Heim, P.A. Krauss

Abstract:	This paper deals with the simulation and the verification with hardware of new architectures for the demodulation of Galileo signals. In a matlab/simulink simulator two architectures for acquisition and tracking of the Galileo BOC(2,2) signal as foreseen for E2L1E1signal are analyzed. For the first architecture only one sideband is tracked whereat for the second architecture both sidebands are used. Due to advantages of the two-sideband approach like the higher signal power and less filter problems it is used for the hardware verification. Due to the ambiguous autocorrelation function of the BOC signal, two bum-jump algorithms are implemented in order to find the right correlation peak. For the verification exercise a simulator for Galileo signals with a hardware transmission chain has been build up. A PC generates the codes and the navigation data. The signal is then modulated with the help of a signal generator and transmitted at 70MHz. At the receiver a modified UNSR (Universal Navigation Signal Receiver; is used with a programmable DSP for the tracking loops. In the hardware simulator five complex correlators are implemented which are needed for the acquisition and tracking of the BOC signals. Both, the local code generator and the local carrier generator are controlled by special tracking loops, similar to the tracking loops used in a GPS receiver. However, due to the multiple maxima of the autocorrelation function of the BOC signals two algorithms are analyzed which use two different verification approaches i.e. an ACF energy evaluation approach and a second discriminator approach in order to detect the highest peak of the ACF. For these algorithms the additional correlators (a very early and a very late correlator) are used. They allow the energy of neighbor correlation peaks to be sampled and by evaluation of these energy measurements the algorithm can decide whether it is necessary to jump to a neighbor peak. The functionality of the hardware Galileo Navigation signal transmission chain has been analyzed and first performance measurements have been carried out.
Published in:	Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003) September 9 - 12, 2003 Oregon Convention Center Portland, OR
Pages:	2021 - 2030
Cite this article:	Fischer, S., Berberich, S., Heim, J., Krauss, P.A., "Simulation & Verification of New Architectures for Galileo Navigation Signal Demodulation," Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003), Portland, OR, September 2003, pp. 2021-2030.
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