[time-nuts] Frequencies used for GPS

[David Kirkby]

Can anyone tell me the transmission frequencies used for GPS?
Wikipedia says 1.57542 GHz (L1 signal) and 1.2276 GHz (L2 signal), but
I'm confused about what the L2 signal is. Is this only of use to the
military since the data is encrypted, or can consumer based GPS
systems use this frequency?

My reason for wanting to know is so I can design an antenna for GPS,
but it wont be used for military purposes, so I've no idea whether I
need to worry about the performance at the lower frequency or not.

As always with Wikipedia, one can't be sure of the accuracy of the
information. I'm guessing someone here will know precise details about
the frequencies used.

Also, what sort of polarisation is used?

If anyone can tell me the desirable characteristics of an antenna for
GPS, I would like to know. The antenna will be mounted outside and
needs to be waterproof, so I'm not looking to fit the antenna in a
small package.


Dave