I've always wondered. Is it just cell sites that have the small GPS antennas or can other communication towers/radio towers have the GPS antennas too?
Any tower can have a GPS antenna. Usually they are used for timing synchronization of different elements in a network. Since the tower is usually stationary, there's not much need for updating the location...well, maybe if there's a hurricane and it blows down the street the GPS will make it easier to find
If it is very close (< a metre??) , the module could be re-radiating. The signal and it is being picked up by the patch antenna, causing overload and signal distortion. You may be able to confirm this by experiment. eg. shielding the module, moving the antenna around. A normal one ohm resistor could have enough inductance (a few nano Henries) to significantly attenuate the 1.5GHz signal.
Late reply...sorry...I've been away for awhile. GPS is used in many industry segments, including radio and TV broadcast; multipoint one way; networked two-way radios, etc. The key is that if you have a need to sync the transmitter/receiver to a larger digital network, the easy way is to using the timing signals available from the GPS constellation. jlk
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148a Safari/6533.18.5) GPS as far as telecommunications it typically used for time synchronization as stated earlier. Unless they are getting time synch from a stratum clock (which are considerably more expensive) it's likely that most if not all sites are converted or built with GPS antennas. These are not only used for radio equipment but other tech industry uses like fiber and video.