Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!dali.cs.montana.edu!milton!hlab
From: campbell@geech.gnu.ai.mit.edu (Paul Campbell)
Newsgroups: sci.virtual-worlds
Subject: Re: Polhemus sensor info request
Message-ID: <1991May6.061910.28639@milton.u.washington.edu>
Date: 6 May 91 04:16:14 GMT
References: <1991May4.213628.9548@milton.u.washington.edu>
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The reason that the sensor would have 3 transmitters and 3 receivers is
that with 3 receivers, you can detect position. Each transmitter creates a
directional magnetic field (the line integral of the magnetic field about
any closed path is equal to the current enclosed by that path. For a
solenoid, the current is out the end of the coil end where the current is
fed in. You can run this in reverse on the sensing coils to get the output
current that the transmitters are generating). With this system, the exact
position and orientation of the Polhemus sensor can be found assuming you can
measure what has to be near micro-micro amperes of current.