[aprssig] News from DCC (5) better Views - AVMAP Dead-Reckoning!

Dave B dave at g8kbv.demon.co.uk
Mon Sep 24 17:07:17 EDT 2012


YAAC does have by default an Age counter next to each object.  That is 
very useful indeed I find.

DR objects going "Off Road" could be very misleading in some instances, 
where a true "Off the Road" situation could indeed be true.  It has it's 
uses, but for many I think it's best left disabled.

I never advocated a "Snap to Road", or "Folow Road" mode for DR, what 
would you do in the event a mobile stopped short of a junction, where 
would the DR go then?

73.

	Dave.


On 24 Sep 2012 at 0:12, Andrew P. wrote:

> So there is no interest in trying to do Snap-to-Road? Good thing;
> that's hard work and depends on high-precision map data and GPS fixes.
> 
> Andrew Pavlin, KA2DDO
> Sent from my Verizon Wireless BlackBerry
> 
> -----Original Message-----
> From: Robert Bruninga <bruninga at usna.edu>
> Date: Sun, 23 Sep 2012 16:12:41 
> To: <aprssig at tapr.org>
> Subject: Re: [aprssig] News from DCC (5) better Views - AVMAP
>  Dead-Reckoning!
> 
> 
> I fear you may be misinterpreting Dead Reckoning.  No one should
> expect a DR line to stay on the road.  The function of the DR line is
> to show the passage of time and distance visually since the last known
> update.  Of course it is probably off the road.  But that is not what
> DR is trying to convey.  It is trying to convey the age of the
> position in time and the growing error of the position in distance in
> an instantly visual way.
> 
> Hope that helps.  It is really great to see it on APRS.FI and now on
> the AVMAP GPS display when pluggedin to a D72 or D710 radio as well as
> most of the modern clients.
> 
> Bob, WB4APR
> 
> -----Original Message-----
> From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On
> Behalf Of Dave B Sent: Sunday, September 23, 2012 9:45 AM To:
> aprssig at tapr.org Subject: Re: [aprssig] News from DCC (5) better Views
> - AVMAP Dead-Reckoning!
> 
> The only problem with DR Bob, is it only realy works with straight
> roads and constant speeds, or in marine/aironautical environments etc
> (where it came from of course.)
> 
> In mountain regions, or other countries (UK/EU) where few of the roads
> are straight (except those made by the Romans many 100's of years ago)
> it rapidly turns into a comedy feature.
> 
> In such cases, mobile objects stray off the road/track for quite a
> distance, before coming back on track when the next posit is sent (if
> it's picked up.)   If a few posits are missed, then the object is
> stranded in the wilds for quite some time.   Somehow, I think it's
> worse with DR than without.
> 
> I know you dislike Smart Beaconing, but that works better in varied
> terrain than DR in my view.   Others may disagree, it's a free world
> (alegedly.)
> 
> 73.
> 
> Dave G0WBX.
> (sort of using YAAC as a creaky satnav while in the US.  Not made it
> talk to my D7 successfully yet, one or the other seems to get p'd off
> with something.)
> 
> 
> On 22 Sep 2012 at 11:18, Robert Bruninga wrote:
> 
> > Don W6GPS demonstrated a beta test of the next release of AVMAP GPS
> > display software that can now display all of the APRS stations on
> > the GPS map but with all moving stations DEAD RECKONED IN REAL TIME.
> > Meaning, now you can see where people really probably are, and not
> > where they were minutes ago.
> >
> > Traveling in parallel with other APRS mobiles and using many
> > existing clients is a joke.  THe ICONS pop up on the map, but then
> > are stuck there as time continues to move on, and the ICON stays
> > stuck on the road a few miles back, until it again snaps ahead and
> > again is obsolete seconds after it was transmitted.
> >
> > WIth DR, the DR indication moves smoothly down the road, so you can
> > always see where he is relative to where you are.
> >
> > Dead Reckoning of live moving symbols on APRS was FUNDAMENTAL to
> > APRS 2 decades ago but was ignored by many clients.  Fortunately now
> > AVMAP, YAAC and APRS.FI and most newer clients (APRSIS32) are
> > including this as the default.
> >
> > Everyone can see how DR works, by just zooming into a moving mobile
> > on APRS.FI.  The track leads the symbol in real time.  Though this
> > is not my ideal choice of display (I prefer to see the symbol move
> > along with its CSE/SPD leader with an anchor back to last known
> > position) but it still lets you see where he really is...
> >
> > Bob, WB4A
> >
> >
> >
> 
> 
> 
> 
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