From: jmelzer@aol.com (JMELZER)
Subject: Re: TECH: tetherless trackers
Date: 8 Sep 1995 21:35:37 -0400


>I'm looking for tetherless trackers (i.e. no wire between transmitter
>and receiver) which can provide 6DOF info at accuracies on the order
>of 1 cm and 0.1 deg, over at least a 5x5 meter area.  Unless I'm
>mistaken, magnetic and acoustic systems require a wire, and radio
>systems have poor resolution.  Any suggestions or pointers?

If you mean "no wires" attached to the user, that will be difficult to get
in 6DOF. Most of the "sourceless" trackers provide 3DOF (angles, not
positions). If you don't mind having the user tethered, you could call
Ascension or Polhemus. Both are magnetic trackers, with long range
extensions. We have used them with success and they are less expensive
than the price you quoted. There is also another company I ran across (I
can't remember their name.) who made a tracker for stage artists. You put
a small ultrasonic receiver on your shoulder/hair, and it makes a couple
of spotlights follow you around. 

What you are asking for is a very high precision system that will work
over a large area. Good luck. I'd be interested in hearing what you find. 

Regards,
Jim Melzer