The GPS satellite s are controlled and
operated by the United States Department of Defense (USDoD).

The GPS satellites currently broadcast on two carrier frequencies: L1 at 1575.42 MHz, and L2 at
1227.6 MHz (future GPS satellites will add additional carrier freq uencies). Each satellite
broadcasts a spread-spectrum waveform, called a pseudorandom noise (PRN) code on L1 and
L2, and each satellite is identified by the PR N code it transmits. There are two types of PRN
codes. The first type is a coarse acquisition (C /A) code with a chip rate of 1023 chips per
millisecond. The second type is a precision (P ) code with a chip rate of 10230 chips per
millisecond. The C/A code is broadcast on L1, and the P code is broadcast on both L1 and L2.
[4, 5, 6] Nearly all of the G PSDOs employed by cal labs use th e C/A code on the L1 carrier as
their incoming reference signal.

 

standards, known as Global Positioning System disciplined oscillators (GPSDOs),   How a GPSDO Works:-

https://tf.nist.gov/general/pdf/2294.pdf

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