From @math.uwaterloo.ca:news@watserv3.uwaterloo.ca Wed Mar 29 17:16:33 1995 Return-Path: <@math.uwaterloo.ca:news@watserv3.uwaterloo.ca> Received: from mx5.u.washington.edu by stein2.u.washington.edu (5.65+UW95.02/UW-NDC Revision: 2.32 ) id AA24610; Wed, 29 Mar 95 17:16:33 -0800 Received: from hitl-new.hitl.washington.edu by mx5.u.washington.edu (5.65+UW95.02/UW-NDC Revision: 2.31 ) id AA08162; Wed, 29 Mar 95 17:16:32 -0800 Received: by hitl.hitl.washington.edu; id AA12366; Wed, 29 Mar 1995 17:12:11 -0800 Received: from watserv3.uwaterloo.ca ([129.97.128.104]) by math.uwaterloo.ca with SMTP id <78161-2>; Wed, 29 Mar 1995 20:16:25 -0500 Received: by watserv3.uwaterloo.ca id <22679>; Wed, 29 Mar 1995 20:16:10 -0500 Newsgroups: sci.virtual-worlds Path: broehl From: broehl@coulomb.uwaterloo.ca (Bernie Roehl) To: sci-virtual-worlds@math.uwaterloo.ca Subject: Re: MISC: Sourceless Tracker Developers Message-Id: Sender: news@watserv3.uwaterloo.ca Nntp-Posting-Host: marconi.uwaterloo.ca Organization: University of Waterloo References: <3lc1sj$t1h@nntp3.u.washington.edu> Date: Wed, 29 Mar 1995 20:15:59 -0500 Status: OR In article <3lc1sj$t1h@nntp3.u.washington.edu>, Sci.Virtual-Worlds wrote: >I'm kind of new to some of the terminology. What is a "sourcless" >tracker? As the name implies, it's a tracking system that doesn't use a "source" or "transmitter". Most tracking systems use magnetic, optical or ultrasonic technologies; all of these involve a transmitter and one or more receivers. Sourceless trackers, on the other hand, are self-contained. All the sourceless trackers that I'm familiar with use the same basic technology, consisting of a two-axis inclinometer and a digital compass (either a simple flux gate or a 3-axis magnetometer). The inclinometer reports pitch and roll to +/- 45 degrees or, in some systems, +/- 70 degrees. The magnetic compass reports a full 360 degrees of yaw information, using the ambient magnetic field of the room. Note that sourceless trackers report 3-axis rotation only; no position information is provided. Sourceless trackers are potentially inexpensive, and all the low-cost HMDs use the same techology. Self-contained sourceless trackers are manufactured by a company called Precision Navigation, but last I heard they were still in the neighbourhood of $600 US in single quantities. -- Bernie Roehl University of Waterloo Dept of Electrical and Computer Engineering Mail: broehl@sunee.uwaterloo.ca Voice: (519) 888-4567 x 2607 work URL: http://sunee.uwaterloo.ca/~broehl