  This paper describes an applicative software tool, named IONORT (IONOspheric
Ray Tracing), for calculating a three-dimensional ray tracing of high frequency
waves in the ionospheric medium. This tool runs under Windows operating systems
and its friendly graphical user interface facilitates both the numerical data
input/output and the two/three-dimensional visualization of the ray path. In
order to calculate the coordinates of the ray and the three components of the
wave vector along the path as dependent variables, the core of the program
solves a system of six first order differential equations, the group path being
the independent variable of integration. IONORT uses a three-dimensional
electron density specification of the ionosphere, as well as by geomagnetic
field and neutral particles-electrons collision frequency models having
validity in the area of interest.
