Understanding GPS: The Nuts and Bolts
SAME-FREQUENCY BROADCASTS
While every GPS satellite has been assigned a unique encoding signature, the Code Division Multiple Access (CDMA) standard is used across the board to unify the scheme. Because CDMA allows for the concurrent transmission of data over a single channel, multiple satellites can send out information to different users on the same bandwidth at the same time. To limit interference, each satellite signal is sent across a widened spectrum.
CDMA for GPS is split into two coding schemes–one is used by the public, while the other is reserved for U.S. military...