Research On Acquisition Algorithm For Mordernized GNSS Signal

With the growing demand of navigation, location, and positioning service, userdevices need more precise positioning capability and higher performance. For this reasonnew signals and modulations will be adopted by new Global Navigation SatelliteSystems(GNSS), such as the Chinese Compass, the European Galileo, and themodernized GPS. Besides new GNSS signal acquisition methods update for these newsignals.Comprehensive analysis for different combining and integration techniques foracquisition of new GNSS signals, and proposal of modified semi-coherent integrationtechniques are contribution of this paper.Modern GNSS signals will be characterized by a data/pilot structure, these twochannels share the total transmitted power. So special acquisition techniques have beendesigned for efficiently recovering all the transmitted power. In this paper three differenttechniques, noncoherent combining, coherent combining, and differentially coherentcombining are analyzed for data/pilot structure. For each strategy the technique structureand probabilities of acquisition process are analyzed. Mote Carlo simulations are used tosupport theoretical analysis and comparison for the performance of different strategies.The problem of navigation data sign transitions is considered when acquiring GNSSsignals over multiple code periods. In this paper, four different integration techniques,noncoherent, coherent, semi-coherent, and differentially coherent integrations areanalyzed by probability characteristic, strategy complexity, and Monte Carlo simulations.In the end, a modified semi-coherent integration technique is proposed for its higheracquisition performance and proper complexity.