[aprssig] smartbeacon fast rate

[Wes Johnston, AI4PX]

One more question Steve.... does smart beaconing beacon as I stop and
enter the slow speed mode?  If I simply pull over and stop on the
interstate, smart beaconing won't beacon my position for possibly 20
to 30 minutes, right?

Wes

On 5/26/07, Steve Bragg <steve at hamhud.net> wrote:
> "Wes Johnston, AI4PX" <wes at kd4rdb.com> wrote:
>
> > Nope... corner pegging is disabled when your speed is
> > highspeed...
> > The pseudo code is missing the open curly bracket after the IF (speed
> > > high_speed) line.... I'll see if I can dig around in the ham hud
> > code and verify this though....
> > This code says to me that if speed not
> > highspeed setting, set beacon
> > rate based on speed/time, set the turn threshold and check for heading
> > changes.
>
> This isn't what I intended, and HamHUD II, the reference SmartBeaconing platform, isn't implemented this way.  The source code is available here:
>
> http://www.hamhud.net/hh2/27004j_40mhz.zip
>
> I have updated the SmartBeaconing page to reflect the HamHUD II code, and my intentions.
>
> http://www.hamhud.net/hh2/smartbeacon.html
>
> I wonder how many other platforms have implemented SmartBeaconing to disable corner-pegging at high speeds.  We truly need to create some kind of SmartBeaconing Working Group to iron out these kinds of misunderstandings.
>
> Some may ask, "why corner-pegging at highway/interstate speeds?" SmartBeaconing is primarily about ensuring that dead reckoning works on mobile APRS trackers under changing conditions.  Corner-pegging provides an extra data point to a dead-reckoning APRS client when the mobile has the high-speed beacons set many miles apart.  Without this extra data point, dead-reckoning will fail on many interstate and federal highways, which have curves that change compass direction significantly in a short distance, at high speeds (for example, the West Virginia Turnpike).
>
> You might reply, "Yes, but you will know the direction when the next fast-speed beacon comes, and extra beacons cause QRM."  Fine.  Just set turn_slope to zero, and the turn threshold won't be adjusted for speed.  Now only corners that cross the fixed turn_min threshold will generate a corner beacon.
>
> Defaults are up to the implementer.  But please don't implement SmartBeaconing in a way that prevents highway corner-beaconing.
>
> 73,
>
> Steve Bragg KA9MVA
> SmartBeaconing co-author
>
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