[time-nuts] GPS receiver vs local oscillator

Hal Murray hmurray at megapathdsl.net
Thu Feb 2 18:49:22 UTC 2012

>> If I want to decode a GPS signal, do I have to know (or figure out) the
>> frequency of the local oscillator?  Or does it drop out of the 
>> somehow? 

> Yes, it comes out in the calculations.
> That's why you need 4 satellites.  You solve for x,y,z and local clock
> offset. (and, in reality you also have to solve for xdot,ydot,zdot, and
> fdot) 


I thought the 4th satellite was needed to determine the time.  Wouldn't it 
take a 5th satellite to also determine the frequency of the local clock?

These are my opinions, not necessarily my employer's.  I hate spam.

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