Marcus Birkl, head of wireless at Siemens, said location tracking of assets or people was one of the biggest incentives for companies, hospitals and education institutions to roll out wi-fi networks.

Both firms were at The Wireless Event, in London, this week selling new products in the area of so-called real-time location services.

Siemens is pushing a complete system, developed with Finnish firm Ekahau, which can track objects or people.

Battery powered

Battery-powered RFID tags are placed on an asset and they communicate with at least three wireless access points inside the network to triangulate a location.

Mr Birkl said: "The tags have a piece of software on them and they detect the signal strength of different access points.

"This information is sent back to the server and it then models the movement of the tag depending on the shift in signal strength detected."

For the system to work, the building or area that has been deployed with a wireless network needs to have been mapped and calibrated.

To effectively locate objects a wireless access point is needed every 30 metres and Siemens said it was able to pinpoint assets to within a metre of their actual position.

Mr Birkl said: "It's very useful for the health care industry - where there are highly expensive pieces of mobile equipment that move around a hospital.

"At every point in the day health staff need to know where it is."

The system can also be used to track wi-fi equipped devices, such as laptops, tablet PCs and wi-fi enabled phones.

"You can record movements over a period of time. You can see if the security guard in the night makes the right rounds, for example," said Mr Birkl.

He added: "You can set certain boundaries and parameters. If a certain device enters or leaves an area it could trigger an alarm."

'More popular'

As wi-fi becomes more popular in schools, the technology could also be used to track students.

"It has to be aligned with the understanding of the people who are tracked," said Mr Birkl.

There have been privacy concerns expressed in some quarters about RFID tags, especially around the possible use of tags on shopping goods to monitor consumer spending habits.

RFID supporters have pointed out that the tags cannot be read at a great distance, but combining the technology with wi-fi raises the possibility of remote tracking.

Tags on products are typically passive - they have no power source and are only activated when read by a scanner in close proximity. These tags contain only an identifying number and can be small enough to embed in a sheet of paper.

But the tags used in conjunction with a wi-fi network have to be active - they need a power source and have software installed on them that communicates with the wireless access points.

The tags, therefore, are larger in size, and currently are impractical for use on anything other than high value consumer goods or, potentially, on people.

"There needs to be standards put in place so the data is not abused for other purposes," said Mr Birkl.

He added: "But there are clear benefits to keeping people safe."

More than half of respondents to a recent pan-Europe consultation on RFID said regulations were needed to police the use of tags.