"Introduction This Report refers to Question 83/8@ DECIDES 4@ i.e. ""Is the sharing of frequencies with other systems feasible@ and if so@ what other systems and under what circumstances?"". The Question is addressed for the radionavigation-satellite system@ global positioning system (GPS)@ which provides accurate---------timing and position determination via two satellite-to-Earth transmission channels. This Report addresses the feasibility of this system sharing the 1215-1240 MHz and 1559-1610 MHz bands with terrestrial stations. A more thorough description of the ----- GPS system and the rationale behind the selection of frequencies is presented in Annex I."