Are you seriously using some mathematical example formula created by teachers from Penn state university Its a formula example how to solve mathematical problem not how GPS actually works Time signal is send by EVERY GPS satellite its actually precise ATOMIC clock time here is a real source Operation Guide for DAGR  httpwebcachegoogleusercontentcomsearchqcacheWPAfxtkXAOsJwwwimefusmcmilexternalwssdeployablevirtualtrianingenvironmentdvtehandoutsgensimtechmanualsdagrDAGRPocketGuidepdfcdhlenctclnkglus