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 Robotics / 2050
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Subject: 
Re: LOGO with Mindstorms
Newsgroups: 
lugnet.robotics
Date: 
Fri, 1 Jan 1999 04:39:24 GMT
Original-From: 
dave madden <dhm@paradigm.webvision&NoSpam&.com>
Viewed: 
1318 times
  
=>From: Matthew Hunter <mhunter@csl.co.uk>
=>...
=>Civilian GPS is encrypted such that your position
=>is only guaranteed to within ~50-100m - fine for a
=>ship or hillwalker but not for an RCX attempting
=>to navigate a room! The error varies each time you
=>get a new position from GPS, so the RCX wouldn't even
=>be able to do relative positioning.
=>
=>So unless you're willing to pay for differential GPS,
=>compass sounds better, especially if you had a bendy
=>robot trying to go round corners with a compass on
=>each end, 'cos then it could tell which way it was
=>oriented......

I think you can simply use two civilian GPSs to do good enough
differential for most purposes.  All you have to do is make sure one
of them is stationary; then, any apparent motion is a result of the
selective availability cruft.  Transmit the apparent motion
information to the mobile unit and it can improve its own idea of its
position.

BTW, GPS cores run about US$180; a site I know of that sells them to
individuals is www.tapr.org.  (They seem to be a Ham radio club, but
I haven't dealt with them.)

d.
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics



Message is in Reply To:
  Re: LOGO with Mindstorms
 
Ralph Deal writes :- (...) GPS on a mindstorm would rock completely, but I'd recommend a compass for the following reason - Civilian GPS is encrypted such that your position is only guaranteed to within ~50-100m - fine for a ship or hillwalker but (...) (25 years ago, 31-Dec-98, to lugnet.robotics)

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