[time-nuts] Nav Receiver Sawtooth Correction?

Bob Stewart bob at evoria.net
Sun Mar 23 21:30:55 EDT 2014


Hi Ignacio,

Thanks for the response.  I've got a UT+ in the parts box.  But that's not the problem I'm trying to solve.  I'm trying to make the best GPSDO that I can make using a nav receiver at the moment.  Call it an obsession if you like.  It's OK if I don't have corrections to the nanosecond for each PPS.  But I can see the nav receiver wandering around; especially on cloudy days, (the antenna is in the attic, so that's about the best I can do for that) and it just seems to me that I should be able to do a general correction for nav position errors.  Sorry if my naive posts are starting to get on people's nerves.

Bob




>________________________________
> From: EB4APL <eb4apl at cembreros.jazztel.es>
>To: time-nuts at febo.com 
>Sent: Sunday, March 23, 2014 7:35 PM
>Subject: Re: [time-nuts] Nav Receiver Sawtooth Correction?
> 
>
>Bob,
>
>The sawtooth is generated by the granularity of the GPS receiver clock 
>not being synchronous with the recovered PPS.  The receiver program can 
>calculate the correction to be applied to the next PPS and outputs it in 
>a message, bu only in timing receivers, this is not a useful thing in 
>navigation receivers and I think that it cannot be calculated using the 
>satellites' position, it is a receiver "defect".
>Why don't you buy a timing receiver?  An used Motorola Encore M12+ 
>timing receiver can be bought by $35 or less (ebay items 290656401551 or
>301131583613.  The seller is a known Time Nuts supplier).  An UT+ or GT+ 
>even for quite less.
>
>Regards,
>Ignacio EB4APL
>
>


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