GPS is not only used for global positioning; many modern electronic communications systems rely on GPS distribution for timing and synchronization.  GPS distribution provides a global and universal time code signal that can be used to synchronize high speed communications between many different devices.  With wireless communications base stations becoming larger and more complex, they are often housed in large equipment rooms in the basements of buildings.  In urban jungle environments, the only clear view of the sky may be hundreds of feet up on the tops of buildings.  This is too far for coaxial cable to provide a GPS signal to this communication equipment.  Fiber optic GPS distribution systems can be used to provide off air timing signals to large amounts of equipment.  Due to fiber optics low attenuation, this signal can originate a long distance from where it is needed.  Distribution of GPS signals via an RF over Fiber system can solve the problems of modern equipment requiring timing signals to work properly.