Hi all,
All GPS satellites transmit on 1227.6 MHz (L2) and 1575.42 MHz (L1).
The L1 carrier transmits the coarse acquisition (CA) codes that are different for each satellite and are not secure so any one with knowledge of the codes may decode the data from these satellites. The precision (P) codes are transmitted on both the L1 and L2 carriers and are secure codes. To use the P code you need to sync using the CA code first.
Jerry.
