Each satellite continuously broadcasts two
signals, L1 and L2. The L1 frequency contains the C/A code which provides
Standard Positioning Service (SPS) for worldwide civilian use. The encrypted
P-code is broadcast on both the L1 and L2 frequency, resulting in the Precise
Positioning Service (PPS) for military use. The SPS signal will provide
a civilian user an accuracy of better than 25 meters.
Who Uses GPS?
GPS receivers provide positioning, velocity
and navigation information for a variety of markets and purposes. Anyone
who needs to know the precise time or the exact location of people or objects
will benefit from GPS. In turn, this information can be used in charting
and mapping, plotting a course, navigating from point to point, tracking
vehicle movement, locating previously identified sites or any number of
similar functions.