Auroral Perturbations as an Indicator of Ionosphere Impact on Navigation Signals

Аннотация

A comparative analysis of total electron content (TEC) fluctuations and auroral activity, which characterizes the polar ionosphere during periods of substorm activity, is performed. The analysis is based on GPS/GLONASS observations at auroral and subauroral stations and data on auroral emissions obtained at the Yakutsk subauroral station and the Poker Flat (Alaska) auroral station. A detailed analysis is carried out for the storm on January 7, 2015. During this event, a sharp increase in the auroral activity and in TEC fluctuations from 09 to 13 UT was observed. A similarity of the dynamics of the auroral oval and the space–time distribution of TEC fluctuations associated with ionospheric irregularities in the oval is demonstrated. There is a close correlation between the positions of the auroral oval and the irregularity oval. The positions of the auroral oval, predicted by the NORUSKA Russian–Norwegian model, and of the TEC irregularity oval are compared. In general, the positions of the ovals are close to each other. The existing discrepancy may be due to the fact that the auroral oval is projected to an altitude of 110 km, whereas the irregularity oval, to an altitude of 450 km, and that the curvature of the magnetic force lines is not taken into account. The influence of auroral disturbances on navigational measurements manifests itself through the fact that, during disturbances, faults and failures in the operation of navigation equipment at auroral and subauroral stations increase.