Validity period ofNeQuick (Galileo version) corrections: trade-offbetween accuracy and computational load

PVT accuracy, in GNSS-based navigation, depends on various factors such as the quality of the measurements and the broadcast navigation data. GNSS broadcast signals (in L-band) are strongly influenced by the atmospheric layers. In particular ionospheric effects are the most important under open-sky conditions. The ionosphere effect can be reduced using linear combination of dual frequency measurements or differential methods. In single point positioning, the receivers have to apply a correction model to limit the ionospheric effect. NeQuick-G is the model developed for Galileo, it out-performs the Klobuchar model, both in the measurement and position domains. These improvements are offset by a higher computational load which is critical, for mass market devices. The main goal of this work is to identify a trade-off between accuracy and computational load; to this purpose NeQuick corrections are not computed every epoch, but only periodically. The effects of this approximation are assessed for several validity periods in the position domain using GPS measurements. The coefficients necessary to use NeQuick-G model are extracted from the Galileo navigation message. From the analysis it emerges that an optimal threshold for the updating rate is about 15 minutes, this reduces the effort of the receiver without degrading PVT.

GIOIA Ciro;  GAGLIONE Salvatore;  ANGRISANO Antonio;  TROISI Salvatore; 

2015-01-23

Institute of Electrical and Electronics Engineers (IEEE)

JRC89720

978-1-4799-5122-2,   

http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6934183,    https://publications.jrc.ec.europa.eu/repository/handle/JRC89720,   

10.1109/ICL-GNSS.2014.6934183,