Real Time MSTIDs Modelling and Application to Improve the Precise GPS and GALILEO Navigation

摘要

The present study will be concentrated on the kind of ionospheric activity so called Medium Scale Travelling Disturbances (MSTIDs). It will be shown that a significant increase of precise navigation service area (in this case Wide Area RTK service area) can be achieved by means of a simple "blind" modelling of the MSTIDs, which can be applied in real-time. This model incorporates its spatial and temporal characteristics, in terms of occurrence and propagation parameters, obtained by the authors in previous works. Neglecting the MSTIDs (as it has been typically done so far), can introduce errors greater than several tenths of TECU, exceeding the exigent limit of 0.25 TECU, and impeding the right carrier phase ambiguity fixing under any technique, and the corresponding accurate navigation. This can easily happen with differences, for instance, of MSTID phases greater than 0.1 cycles, which can appear under distances of ～15 km or greater, considering a typical MSTID wavelength of 150 km. This can occur in any part of the Solar cycle, without geomagnetic activity and at mid latitude, for instance.