1,721,006 research outputs found
"Optimization of corse synchronisation performances by non-linear signal pre-processing of GNSS signals in radar jammed environments"
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"Metodi di ricerca basato sulle caratteristiche geometriche delle orbite per sky search in sistemi GPS"
No full text"Theoretical Analysis of S-curve for GNSS System"
No full textThe GPS system improvement and the Galileo system development will increase the signal availability and therefore the GNSS system-based applications. The great evolution of GNSS based application will imply the growth of precise and fast navigation systems. The performances of GNSS systems are mostly influenced by the accuracy of the synchronization modules. In fact, loss of fine tracking means a less precise position estimation. In urban environment the receiver measurement is usually affected by errors, especially caused by multipath fading. For this cause could be useful to analyze the performances of different methodologies to solve this problem proposed in literature. In this paper, a theoretical model valid for the analysis of synchronization performances in GNSS receivers in a urban environment is proposed. The proposed model is studied under the presence of two important cause of disturbances, named gaussian noise and multipath, in the received signal. In general the S-curve is shown in the ideal case, without any source of noise. A model can permit to recognise the presence of different type of noise that act on the received signal. The validation of the method will be made comparing results derived from signals from a simulated environment with the theoretical model. Performed tests have pointed out the validity of the theoretical model in a real case
Neural Networks Based Approach For Fine Tracking in Satellite Navigation Systems
No full textIn this paper a novel method to solve the fine synchronization problem in GNSS receivers is presented. In fact the extended evolution of GNSS-based applications will imply the growth of fast and precise navigation systems. The aim of this study is to found an alternative solution to the classical non-coherent Delay Lock Loop. In particular, the proposed method, based on Self Organizing Map (SOM) a particular type of Neural Networks, allows to improve the performances in multipath channel
"Neural Networks algorithms for Improving Delay Lock Loops Performances for Navigation Satellite Systems in urban environment"
No full textIn this paper a novel code tracking algorithm is proposed which can be used in GNSS receivers. Classical code tracking approaches consider AWGN channels as an hypothesis for designing theoretically optional trackers. However, this hypothesis does not hold in multipath channels. The method proposed, based on neural networks, provides results that outperform classical DLL trackers
"Integrazione di sistemi di navigazione satellitare e comunicazioni cellulari tramite tecniche basate su software radio"
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