|Home < Products < Components < Position Trackers|
Motion/Position Sensors and Instrumentation
Real-Time Tracking of the Physical Environment
Position tracking can have many levels, from measuring head orientation down to measuring individual fingers. Position tracking allows one to get a sense of their own presence within the synthetic environment, as well as their virtual limits within the simulation.
Position tracking implies both position and/or orientation tracking. The simplest position trackers are the joystick and mouse, which are planar devices. The minimal position tracker discussed here will be able to measure at least three degrees of freedom (DOF) simultaneously in space. There are many ways to track position: Magnetic, Optical, Acoustic, Mechanical, and Inertial.
Magnetic - Currently, magnetic trackers are the most widely used. They utilize an emitter and detector configuration. The emitter is attached to the environment and emits orthogonal magnetic fields.
Optical - There are many ways to track objects optically; however, all depend on light in some way. Some systems are passive, and take in the ambient light and process it, while other systems actively scan the scene with lasers.
Acoustic - Use ultrasonic sound emitted by a radiator (high frequency speaker) and received by special microphones. Either the emitters or receivers can be mounted on the moving object(s). A single emitter and receiver can measure the distance to an object.
Mechanical - Also known as goniometers or exoskeletons, measure a person's limb positions via mechanical linkages. The exoskeleton must be physically attached to the user.
Inertial - Measuring the accelerations on masses (accelerometers) or the orientation of spinning masses (gyroscopes). Integrated circuit technology has advanced to the point where these sensors are small enough to be used in human position tracking. Linear accelerometer and gyroscopic information are subject to drift, which can be auto-corrected by "sensor fusion," i.e. utilizing multiple types of sensors.
Position Trackers / University of Utah / by James.Kolozs / revised 5-28-1996
|[Home] [About AuSIM] [Products] [Services] [Applications]||
|[Support] [Contacts] [Buy Online] [Downloads] [News & Events]|
|© AuSIM Inc. 1998-2011. Last updated on|