[time-nuts] Jupiter GPS receiver

Magnus Danielson cfmd at bredband.net
Thu Jan 5 20:01:20 UTC 2006


From: Alberto di Bene <dibene at usa.net>
Subject: Re: [time-nuts] Jupiter GPS receiver
Date: Thu, 05 Jan 2006 19:02:25 +0100
Message-ID: <43BD5F31.3090701 at usa.net>

> Magnus Danielson wrote:
> > 
> >>I looked in my data and their spec sheet shows +/- 1 microsecond.  But, 
> >>I beleive this was much better than that.  I cannot find it, but I 
> >>beleive I seen a report where somebody compared the Jupiter and it was 
> >>in the 120 to 150 nanosecond class.
> > 
> > 
> > +/- 1 microsecond is the old worstcase garantee for the GPS system. It is was
> > you can expect from a GPS with lack of satellites, SA and old style satellites
> > going out of date in their predicted orbits data.
> > 
> > These days we have better satellites, full system and no SA. Add to that much
> > improved receivers (no more 1 channel receivers as in the good old days).
> > 
> Brian and Magnus,
> 
>   thanks for your input. It looks like I can, after all, use that Rockwell board
> without resorting to huge integration times for the 1pps signal.
> 
> Just curious on another topic : I have seen advertized GPS boards with 20-channel
> capability, Given that, at least based on my direct experience, even with a clear
> horizon you rarely have 12 satellites in view, what does buy you having that
> capability available?  TNX.

Forward compatibility to Galileo. Then you can track GPS and Galileo at the
same time. Also, you can track the additional signals from the modernized GPS
satellites. I don't expect the boards of today to be fully optimized for that
just yeat, but they will certainly outperform GPS only solutions which only
does L1 C/A.

Cheers,
Magnus




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