[time-nuts] Compensating phase differnces in dual frequency GPS receviers?

Peter Monta pmonta at gmail.com
Wed Nov 30 22:56:25 EST 2011

Hi Attila,

> [ L1 / L2 timing differences ]
> How do dual frequency receivers deal with that?

I've also been toying with the idea of an inexpensive dual- or
tri-band GPS SDR, especially since there are now quite a few
satellites emitting L2C, the civil L2 signal.  (Though I'd still like
to try my hand at the fancy L2 semicodeless schemes.)

I think that manufacturers calibrate out the timing differences
between channels (as well as group-delay variations within a channel).
 There must be some remaining error, though, e.g. over temperature,
depending on the filter technology.

ObTimeNuts:  There's an interesting recent thesis on GPS for time and
frequency metrology:


Section 5.1.3 has a few words on exactly this channel-filter-delay
issue.  The author measures a coefficient of 20 ps per degree for a
pair of receivers.


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