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[DPRG] Long Haul Way Points

Subject: [DPRG] Long Haul Way Points
From: Kipton Moravec (SPEC Manufacturing) kip.moravec at specmanufacturing.com
Date: Mon Sep 11 15:37:33 CDT 2006

So does that mean you are volunteering to bring one of your units to Fair
Park and take measurements we can use for the robot competition?

Kip

> -----Original Message-----
> From: dprglist-bounces at dprg.org [mailto:dprglist-bounces at dprg.org]On
> Behalf Of John Harrison
> Sent: Monday, September 11, 2006 9:58 AM
> To: '-Old Dog-'; 'David P. Anderson'; dprglist at dprg.org
> Subject: RE: [DPRG] Long Haul Way Points
>
>
> Hello DPRG list.
>
> I have just found your organization on the net and joined (have
> not been to
> a meeting yet).  I am coming into this mail thread in the middle of it so
> this may be a little out of context, but my company designs and sells GPS
> auto steering systems for agriculture and road construction.  I am the
> designer and have had systems in the field for the last 5 years.  I have
> tried about every GPS imaginable.  The golden rule of accuracy and
> repeatability is "you get what you pay for".
>
> Our customers require, at a minimum, 4 inch short duration
> repeatability and
> 12 inch long duration repeatability.  This is impossible to get from any
> sports receiver.  Base band GPS is only accurate to about 30 - 60 feet
> (depending on single or dual channel).  Our experience with WAAS
> is that it
> is better than the publicized specs, but has had some reliability problems
> lately.  We have been seeing approx 24 inches of long duration
> repeatability
> from WAAS.  The best repeatability, by far, is from the purchased
> correction
> services.  Our products have completely gone with the purchased services
> even though the receivers are over $5500 (at the low end).  The published
> specs on these receivers are 12 inch long duration repeatability, but we
> have been seeing closer to 6 inch.  All of these specs are statistical so
> repeatability is a little bit relative to you level of pain.
>
> If you want centimeter accuracy you can go with a dual channel RTK system
> with a base station, but you are talking about big $$$$ (price is coming
> down).  If any of you are interested, I would love to design an
> RTK system.
> The price for purchased systems are totally inflated relative to
> the actual
> hardware needed.
>
> I hope that this may have helped.
>
> New Member
> John H. Harrison Jr
> Harrison Ag Technologies
> Johnh630 at comcast.net
>
>
>
> -----Original Message-----
> From: dprglist-bounces at dprg.org
> [mailto:dprglist-bounces at dprg.org] On Behalf
> Of -Old Dog-
> Sent: Sunday, September 10, 2006 1:31 PM
> To: David P. Anderson; dprglist at dprg.org
> Subject: Re: [DPRG] Long Haul Way Points
>
> All:
>
> The differences in GPS coordinates don't come as any
> surprise to me. That's why I also described the course
> in terms of headings, distance, and pictures. After
> yesterday's meeting two potential competitors walked
> the course with their GPS's, and noted discrepancies
> between their readings. If they'd like to share their
> results, I'd be interested in comparing them to what
> I've already calculated. The maximum difference
> between what yours and my readings are about 2/1000.
> That doesn't sound like much; until you realize how
> much distance a single degree covers.
>
> What does surprise me is not being able to get a lock
> at some key way points. When mapping the course, I
> made sure I could get at least 5 satellite's per mark.
> But I wanted this to be a contest of ingenuity, rather
> than who has the best equipment. In that spirit, Eric
> offered an interesting suggestion yesterday, when
> another GPS had the results you mentioned: Activate
> your robot far enough away from the building to get a
> satellite lock prior to the start of the attempt. Then
> direct the robot to the starting area, and use
> odometry to compensate. There is nothing in the rules
> about taking that approach.
>
> > For those who might like to try another challenge
> while we are at FiarPark,
> > here are the 2 waypoints to go from the meadow next
> to the Science Place
> > to the meadow next to Texas Star Ferris wheel, which
> must circumnavigate the
> > Band Shell, as jBot demonstrated in a round trip a
> few months ago:
>
> I have no problem with this, provided it does not
> disrupt the planned contest or distract from the
> people running attempting to compete.
>
> -Martin
>
>
> --- "David P. Anderson" <dpa at io.isem.smu.edu> wrote:
>
> > Howdy,
> >
> > I went by Fair Park yesterday to verify Martin's
> > waypoints and got the
> > following.  John, you might try these out with
> > Google Earth:
> >
> > start:	N  32.77715
> > 	W 096.76190
> >
> > waypt1	N  32.77753
> > 	W 096.76208
> >
> > waypt2	N  32.77770
> > 	W 096.76266
> >
> > waypt3	N  32.77790
> > 	W 096.76249
> >
> > Note that these are specified in decimal degrees
> > (hddd.ddddd) as are Martin's
> > rather than degrees-minutes-seconds.
> >
> > The first waypoint is in the shadow of the Science
> > Place building on two sides
> > and I was only able to get three satellites at that
> > location, so it is not
> > a very accurate measurement.  Likewise with waypt2,
> > which is in the building
> > shadow and also under a large tree.
> >
> > For those who might like to try another challenge
> > while we are at FiarPark,
> > here are the 2 waypoints to go from the meadow next
> > to the Science Place
> > to the meadow next to Texas Star Ferris wheel, which
> > must circumnavigate the
> > Band Shell, as jBot demonstrated in a round trip a
> > few months ago:
> >
> > start:	N   32.77634		// Water cover next to TSP
> > 	W  096.76179
> >
> > end:	N   32.77631		// In front of Ferris Wheel.
> > 	W  096.75965
> >
> >
> > A little more challenging is the route from the
> > Science Place meadow,
> > across the entrances and parkinglots to the field
> > behind the Natural
> > History Museum:
> >
> > start:	N  32.77636		// Water cover next to TSP
> > 	W 096.76179
> >
> > end:	N  32.77821		// Behind Nat'l Hist Museum
> > 	W 096.76369
> >
> >
> > For those without obstacle avoidance working, you
> > might want to at least
> > run a demo course.  Here is one laid out earlier
> > this year. This was for
> > those who might have a navigating robot but don't
> > have obstacle avoidance
> > working yet.
> >
> > It begins in front of the Cotton Bowl and has a
> > second
> > waypoint at a bend in the road, and a third point in
> > front of the Aquarium where the path is blocked.
> >
> > Plaza in front of Cotton Bowl (intersection of brick
> > paths):
> >
> > start:	N  32.77790 		// Cotton Bowl Plaza
> > 	W 096.76112
> >
> >
> > waypt1	N  32.77707 		// Corner of Band Shell:
> > 	W 096.76085
> >
> >
> > finish:	N  32.77654		// In front of Aquarium
> > 	W 096.76042
> >
> > Here is an ariel view with the route marked out in
> > red, from
> > upper left to lower right:
> >
> >
> <http://geology.heroy.smu.edu/~dpa-www/robo/jbot/jbot2/fairpark2_x.jpg>
> >
> >
> > best,
> > dpa
> >
> >
> > John wrote:
> > > I plotted the way points with Google Earth.  I
> > don't know what is ground
> > > truth, that is Google Earth also has errors.  I
> > was comparing them to
> > > the map posted on the web.
> > >
> > > Start:  Was in the grass NNE of the round doom.
> > > WP1:  Looked like it is on the edge of the
> > sidewalk.
> > > WP2:  Halfway between building and sidewalk, 8
> > meters from the corner of
> > > the building (to the southeast)
> > > Finish:  Across 2d street in the parking lot 195
> > meters from WP2.  This
> > > point was also located here by TopoUSA.  Since
> > TopoUSA doesn't show the
> > > building (all of Fair Park is just a green blob) I
> > couldn't use it to
> > > verify the other points.
> > _______________________________________________
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> > DPRGlist at dprg.org
> > http://list.dprg.org/mailman/listinfo/dprglist
> >
>
>
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