The system has a mean time between failure of around 600 hours, and can track at least 60 targets at once.

For hours, its sensory system had been tracking the strange sound above.

Bean's first achievement was to find the way the teachers' system tracked student computer activity.

The system tracked west-northwest, a course it would continue through its life cycle.

The system tracked westward and was observed by a research flight on August 18.

The system tracks each response and sends an alert back to the user along with contact information for the new lead.

If customers accept the offer, the system can then track their network use by address and time, no matter where they go on the Web.

Trucking companies, for example, use the system to find and track their trucks across the country.

The system could track only one target at a time.

Such a system would track doors entered and times.