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[DPRG] Long Haul Way Points

Subject: [DPRG] Long Haul Way Points
From: John Harrison johnh630 at comcast.net
Date: Mon Sep 11 16:18:31 CDT 2006

I can meet anytime on Thursday, or Friday morning.

John

-----Original Message-----
From: dprglist-bounces at dprg.org [mailto:dprglist-bounces at dprg.org] On Behalf
Of Kipton Moravec (SPEC Manufacturing)
Sent: Monday, September 11, 2006 4:15 PM
To: John Harrison
Cc: dprglist
Subject: RE: [DPRG] Long Haul Way Points

When do you want to go down there?  I want to see how my GPS board compares
to yours.

Kip

> -----Original Message-----
> From: John Harrison [mailto:johnh630 at comcast.net]
> Sent: Monday, September 11, 2006 3:52 PM
> To: kip.moravec at specmanufacturing.com
> Cc: 'dprglist'
> Subject: RE: [DPRG] Long Haul Way Points
>
>
> Yes, I have an old one available that we could take some measurements.
>
> John
>
> -----Original Message-----
> From: Kipton Moravec (SPEC Manufacturing)
> [mailto:kip.moravec at specmanufacturing.com]
> Sent: Monday, September 11, 2006 3:38 PM
> To: John Harrison
> Cc: dprglist
> Subject: RE: [DPRG] Long Haul Way Points
>
> 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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> > >
> >
> >
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>

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