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تسجيل مستخدم جديدA case study of the mid-latitude GPS performance at nighttime during the magnetic storm of July 15, 2000
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Using the geomagnetic storm of July 15, 2000 as an example, we investigated the dependence of GPS navigation system performance on the nightside at mid-latitudes on the level of geomagnetic disturbance. The investigation was based on the data from the global GPS system available through the Internet. It was shown that the number of GPS phase slips increases with the increasing level of disturbance and that there is a good correlation between the rate of Dst-variation and the frequency of slips. It was further shown that the relative frequency of slips has also a clearly pronounced aspect dependence. Phase slips of the GPS signal can be caused by the scattering from small-scale irregularities of the ionospheric E-layer. Phase slip characteristics are indicative of Farley-Buneman instabilities as a plausible physical mechanism that is responsible for the formation of geomagnetic field-aligned irregularities. Using simultaneous measurements of backscatter signal characteristics from the Irkutsk incoherent scatter radar and existing models for such irregularities, we estimated the order of magnitude of the expected phase fluctuations of the GPS signal at a few degrees.
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Basic properties of the mid-latitude large-scale traveling ionospheric disturbances (LS TIDs) during the maximum phase of a strong magnetic storm of 6-8 April 2000 are shown. Total electron content (TEC) variations were studied by using data from GPS
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E.L. Afraimovich
, V.V. Demyanov
, T.N. Kondakova (Institute ofn Solar-Terrestrial Physics
2002
The GPS performance is impaired in conditions of geomagnetic distrubances. The rms error of positioning accuracy increases in the case where two-frequency GPS receivers of three main types (ASHTECH, TRIMBLE, and AOA) are in operation. For ASHTECH rec
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