Mathematical modeling of the earth''S upper atmosphere from the transport infrastructure point of view

Nowadays the importance of satellite navigation systems is growing due to their ability to solve various problems in different areas of Russian economics and public sector. The GLONASS national system has been developed since 2001 according to the federal target programme. The paper demonstrates examples of GLONASS applications in different fields of Russian transport system including automobile, railway, and water transport. Any navigation system has its inaccuracies caused by a number of factors. The paper focuses on inaccuracies of detecting an object location related with signal propagation from a satellite through the ionosphere as a conductive medium. These inaccuracies increase in high latitudes because of inclination angle of the navigation satellite orbit and under specific geophysical conditions such as geomagnetic storms and substorms. Modern navigation systems use statistical models for ionospheric delay calculation. Such models are developed by averaging great value of measurement data and cannot provide high accuracy of object location detection under disturbed geophysical conditions and in high latitudes. By ionospheric delay calculations the coefficients of statistical ionospheric model can be corrected using a self-consistent mathematical ionospheric model. The authors suggest using the global numerical Upper Atmosphere Model (UAM). The UAM takes energetic particles precipitation and field-aligned currents in the auroral areas into account. The model reproduces ionospheric behavior in high latitudes under various geophysical conditions sufficiently.