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

Attila Kinali attila at kinali.ch
Fri Dec 2 07:59:54 EST 2011

On Thu, 1 Dec 2011 19:56:12 -0800
Peter Monta <pmonta at gmail.com> wrote:

> > So, that'd mean there would be an automatic calibration system inside
> > the device, because i dont have any equipment with which i could
> > calibrate delays over a temperature range.
> I suppose they could do that---provide a weak broadband source (say a
> comb) combined with the antenna signal prior to the channel filters,
> and provide a reference channel for this calibration signal to compare
> against on-line.

Juup, i thought exactly at that. Use a dirac pulse generator with
a ~100MHz comb. That would generate nice signals in the L1 and L2 bands.
This could then be measured later... But it's ugly, and you have to deal
with either switching of the input source, or have to distinquish the
calibration signal somehow from the normally received signal.

>   Or they could calibrate just once at production
> time, which would be less expensive---the system would then compensate
> open-loop based on temperature.

Yes, but that requires expensive equipment.

			Attila Kinali

The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
		-- Tirin, The Dispossessed, U. Le Guin

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