Transmitted power: 14.9 dBW

Transmitter Antenna Gain: 13.4 dB

Thanks Ali, any particular references, though ? 

You can find all the information on the ICD GPS technical documents available at https://www.navcen.uscg.gov/?pageName=gpsTechnicalReferences

Also the presentation available at

http://www.gps.gov/multimedia/presentations/2010/10/ICG/betz.pdf

An example is reported in : http://gpsinformation.net/main/gpspower.htm

Thanks a lot Ciro