On Wed, 01 Dec 2004 16:06:58 GMT, Geoff Schultz
wrote:

Did I also mention that I have a RayMarine MaxiView display that I can
also see from the berth and I can program it to display any of the
instrument data such as wind/depth/course/speed/etc? :-)

Actually, I think that's an excellent idea, but I rolled my own. See
the crass commercial message in my sig. :-) I've been asked to
extend the program with an intelligent anchor watch. Something
that would suppress spurious alarms when the gps loses lock for
a few seconds. I'd never have thought of that myself, but it's a
fact that I've never had a complete night without my gps deciding
Scotty beamed me a few hundred yards in some random direction.
Which causes OziExplorer's otherwise excellent anchor watch to
start screaming.

It's doable, but the data filtering will be tricky. I've found that
you can't always trust the gps to notice that it's lost accuracy, so
I'll have to implement some kind of statistical filter that ignores
the big jumps but notices a small steady drift.

I haven't quite worked out how to handle wind and current reversals
yet. If you could do that, you could tighten the safe distance quite
a bit. It seems that treating the safe swing area as a circle around
your current position, as anchor alarms do, is wrong. It's really a
circle around the anchor's position. Maybe a bearing and distance to
the anchor float could be used as an offset to current position?
__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at world wide wiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/