[time-nuts] Frequencies used for GPS

Magnus Danielson magnus at rubidium.dyndns.org
Thu Oct 20 03:39:05 EDT 2011


On 10/20/2011 03:25 AM, David Kirkby wrote:
> 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.

Traditional GPS provides C/A and P(Y) signals on L1 and P(Y) signal on L2.

A typical civial GPS only receives the C/A signal.

I have four L1/L2 receivers, which can use the P(Y) signal on both L1 
and L2.

Modern GPS satellites provide L2C on L2, which is a civilian signal as 
well. Another modernisation is the L5 signal which is also a civilian 
signal. Notice that bandwidth has increased from 20,46 MHz to 24 MHz in 
the modernisation.

If you can will GPS L1, L2 and L5 be of interest.

Then there is GLONASS L1 and L2.

Then there is GALILEO myriad of spectrums.

Cheers,
Magnus




More information about the time-nuts mailing list