[time-nuts] Progress of my HP Z3801A -- Ooops!

Magnus Danielson cfmd at bredband.net
Wed Aug 30 21:28:52 UTC 2006


From: bg at lysator.liu.se
Subject: Re: [time-nuts] Progress of my HP Z3801A -- Ooops!
Date: Wed, 30 Aug 2006 22:59:07 +0200 (CEST)
Message-ID: <64333.212.181.149.145.1156971547.squirrel at webmail.lysator.liu.se>

> On Wed, August 30, 2006 22:23, Magnus Danielson said:
> 
> > The current state is on:
> > http://rubidium.dyndns.org/gpsdata/
> >
> 
> Should this
> 
>     "Satellites(Tracking/Visible): 6/3"
> 
> be read as; Tracking 6 SVs, 3 more should be visable over the 10 deg
> horizon mask, but are not used now?

Yes. Those numbers are also quite typical. I have sometimes have 12 or ever 13
visible satellites.

Many are however lo-sniffers, so they are either in the rising or in the
decending.

I have considered making a signal-strength map of my sky, through the continous
logging of signal-strength versus Asimuth/Elevation angle, and then use that to
actively remove satelites which is in nonfavourable positions from the list of
available satellites. Doing that actively I could possibly have a lower
horizontal mask as I effectively punch out a 2D mask in its place. It doesn't
take that much of programming to do. Some care must however be taken to observe
the variation of signalstrength in each sector. A little more advanced variant
would look at how pseudo-ranges changes in different directions and set the
2D elevation mask such that a maximum pseudo-range error is accepted, again
will variations be necessary ingredience for correct result. CPU cycles doesn't
come back, so waste them while you can!

Cheers,
Magnus




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