Newsgroups: comp.robotics
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From: andrewfg@aisb.ed.ac.uk (Andrew Fitzgibbon)
Subject: 6 DOF position sensors
Message-ID: <Czs0uv.n2G@aisb.ed.ac.uk>
Sender: andrewfg@aisb (Andrew Fitzgibbon)
Organization: Dept AI, Edinburgh University, Scotland
Date: Thu, 24 Nov 1994 14:42:30 GMT
Lines: 37

Hi,

I'm looking for an *accurate* 6 DOF position sensor -- something like
the Polhemus or Ascension units described in the comp.robotics FAQ, but
those units appear to have rather poor accuracy.  Surely if GPS [*] can
give 1 metre over hundreds of miles [**], it seems implausible that I
can't get below 2mm over a metre cubed?

I'd like to hear from anyone who has experience of these or similar
sensors, particularly in the metre^3 workspace size range, and
particularly those looking at sub-millimetre problems[***].  
  What accuracy to you typically get?  
  Repeatability?  
  How large is your sensor?  
  How much?  
  Do you need line-of-sight to the transceiver? 
  Does it suffer ferrous metal interference?

Feel free to mail responses -- I will happily summarize once I
have gathered the information.

Thanks in advance,

Andrew.

[*] Differential GPS for non-US Military.
[**] O(100) satellites over O(10000) miles translating to ~100
     miles per 3 satellites
[***] I do have a real need for accuracy.


-- 
Andrew Fitzgibbon (Research Associate),                     andrewfg@ed.ac.uk
Artificial Intelligence, Edinburgh University.               +44 031 650 4504
                        http://www.dai.ed.ac.uk/staff/personal_pages/andrewfg
       "If it ain't broke, don't fix it" - traditional (c1950)
          "A stitch in time saves nine." - traditional (c1590)
