Subject:
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Re[2]: GPS Reality?
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 11 Apr 2005 20:43:16 GMT
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Reply-To:
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Allen Foster <Kaptain.korolev@ntlworld.com>
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Viewed:
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3994 times
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Apologies for my rather inconsistent memory, it was Evolution Robotics
rather than iRobot. Still a good idea though in my opinion.
http://www.evolution.com/products/northstar.masn
http://www.pcmag.com/article2/0,1759,1682951,00.asp
Anyone ever ordered a dev. kit?
Allen.
Monday, April 11, 2005, 3:31:01 PM, you wrote:
AF> I'm a lurker, so apologies for jumping into your conversation.
AF> I believe iRobot patented an interesting system last year called
AF> 'Polaris' or something similar which used the principle of navigating by
AF> the stars to position a robot platform in an indoor environment.
AF> Several dots of light (presumably IR) were projected onto the ceiling of
AF> a room by a base station and mobile robotic platform in the environment
AF> then used the observed parallex differences in viewing the dots from
AF> different locations in the room to position themselves.
AF> At least that's what I remember, probably wrong. An intriging idea none
AF> the less though.
AF> Allen.
AF> danny staple wrote:
> > A solution I suggested on the DPRG list was that if radio telemetry is
> > being sent to and from the robot, then to have each robot with a
> > clearly identifiable dot- rather like a police car - on the top. You
> > could then have a camera covering the arena, and a desktop machine
> > with visual processing software to work out the relative position of
> > the dot, then communicate this back to the bot with the telemetry.
> > However - this would only work in a very small space.
> >
> > Also - it would limit the choice of colours, as Lego colours tend to
> > be very saturated colours, which are what this technique normally uses
> > to find stuff. We are back to visual processing now - but at least it
> > is now taken off the bots.
> >
> > Another idea is to have an infra-red emmiter on the robot, and (in a
> > relatively unobstructed arena), sensors along the two horizontal axes.
> > Each robot broadcasts a different ID, and the arena systems use the ID
> > along with the sensors getting the clearest signal to send the robot a
> > radio signal back with the ID of the sensors or full coords. The
> > problem is that this approach needs a lot of sensors - its off the top
> > of my head, and I get the feeling dealing with multiple IDs while
> > doing strength comparisons from that many sensors may not be
> > particularly easy. This could be reversed with IR LEDs each
> > broadcasting a narrow beam coordinate along the side and front/back of
> > the arena- and the robot using this to infer its position by
> > differentiating the strongest signals. If the robot had a wide sensor,
> > while the beams were quite tight - that might actually work. But again
> > - you need a lot of beams, and a relatively unobscured arena.
> >
> > Yet another is to use three Ultra-sound beacons again, but modulating
> > the ultra-sonic signals to include a time code - I get the feeling
> > that this may be too hard - although it is closest in function to what
> > you actually get from the GPS satellites.
> >
> > The thing is - it is worth taking for granted that most of the
> > solutions will require specialist equipment in the arena - which
> > considering GPS relies on the satellites - is not an unreasonable
> > requirement.
> >
> > Danny
> > --
> > http://orionrobots.co.uk - Build Robots
> >
> > On Apr 11, 2005 2:14 PM, PeterBalch <lego-robotics@crynwr.com> wrote:
> >
> >
> > > > three sonar beacons,
> > > > which are broadcast a radio ping, and then transmit each of their
> > > >
> > > >
> > > signals.
> > >
> > >
> > > > The bot controller than uses the time difference between the request
> > > >
> > > >
> > > radio
> > >
> > >
> > > > ping, and the sonar reply to work out its position.
> > > >
> > > >
> > > So the robot works out it's best guess from the three intersecting circles.
> > >
> > > Of course, the radio signal is not strictly neccessary. Beacon A broadcasts
> > > it's beep. Beacon B hears A, waits a fixed delay then broadcasts it's beep.
> > > Beacon C hears A, waits a longer delay time then broadcasts it's beep. Etc.
> > > The robot hears the beeps (in order A, B, C, ... because the delays are
> > > long enough). It works out it's best guess from the intersecting
> > > hyperbolae.
> > >
> > >
> > >
> > > > JB: I've worked with a number of "solutions" but none of them are
> > > > anything I'd recommend.
> > > >
> > > >
> > > What's the best you've see so far?
> > >
> > > Peter
> > >
> > >
> >
> >
> >
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Message is in Reply To:
 | | Re: GPS Reality?
|
| I'm a lurker, so apologies for jumping into your conversation. I believe iRobot patented an interesting system last year called 'Polaris' or something similar which used the principle of navigating by the stars to position a robot platform in an (...) (21 years ago, 11-Apr-05, to lugnet.robotics)
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