Answer 5

No, but this is a common misconception.

Actually, the chip rate has very little if anything to do with the overall accuracy; the quality of the correlators and local clock in the receiver is the real limitation. The main reason military receivers have higher accuracy is that they get access to two different carrier frequencies, which allows them to measure and compensate for atmospheric refraction in real-time. The L1 carrier at 1575.42 MHz carries both the C/A and P(Y) signals, while the L2 carrier at 1227.60 MHz carries only the P(Y) signal.

If you have a clock and correlators that are capable of using the P code, they'll do just as well on the C/A code. The key is how well you can align on the transitions between chips, not how far apart they are.

Contributor: Dave Tweed

Published March 2003