[time-nuts] how good an oscillator do you need for a GPS simulator

Chris Albertson albertson.chris at gmail.com
Fri Dec 16 01:25:57 EST 2011


For testing, I'd assume the gps simulator only needs to be good enough
that the receiver will detect the signal.   There is some Doppler
shift so the receiver must have to look over a wider range of
frequencies so if the simulator was inside that range it could work.
 Light travels at about one foot per nanosecond.   so your simulator
should need to know the time to within a few tens of nanoseconds.
Receivers can deal with not-perfect signal.  Multipath and refraction
are common.

You GPS simulator would likely have a GPS receiver inside of it and
sync to a real GPS.
On Thu, Dec 15, 2011 at 9:37 PM, Jim Lux <jimlux at earthlink.net> wrote:
> Say you want a quik n easy n cheap GPS simulator to test a GPS timing
> receiver.  How good does the oscillator (presumably some nice multiple of
> the chip rate) have to be?
-- 

Chris Albertson
Redondo Beach, California




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