A ray tracing model for beam footprint boundary in cognitive satellite communication applications

Characterizing the satellite beam footprint boundary can be used to measure the overlap of the beam coverage area of a satellite with that of other communication systems. A crucial application of this is in emerging cognitive satellite communication systems. In this paper, an analytical model based on ray tracing is proposed for specifying the boundary and the size of the satellite beam footprint and the distance of the footprint center from the beam center on Earth's surface. These characteristics are primarily a function of four parameters, namely, the coordinates of satellite, the beam cross-sectional shape, the coordinates of beam center, and the beamwidth. These parameters are reduced to only two parameters of Earth central angle between the nadir and the beam center and the beamwidth. Numerical results show that by increasing any of the two parameters the asymmetry of the footprint, its size, and the distance between the footprint center and the beam center increase.