A statistical approach to specifying the off-axis EIRP spectral density in on-the-move satellite communications

The mobile very small aperture terminal is a new satellite terminal with applications in both military and commercial sectors. In some terrains, antenna pointing errors of these terminals may exceed satisfactory limits. In these terrains, since these errors may increase interference to neighboring satellites, it may be necessary to reduce the effective isotropic radiated power (EIRP) spectral density transmitted to satisfy the strict regulatory off-axis emission requirements. In this paper antenna pointing errors are considered as random variables and analysis carried out to characterize the probability that the EIRP spectral density exceeds its regulatory mask. This analysis can be used to specify a new mask for the off-axis EIRP spectral density for these terminals. The objective of this work is to develop a new ITU-R recommendation for mobile very small aperture terminals and this constitutes some of the contributions made to the ITU-R Working Party 4A Group.