London: A new online tracking system will allow websites to pinpoint your location to within a few hundred metres, even without your permission. Internet sites will be able to work out where users are within an average of 690 metres, using information about their internet connection.

At the moment they can only track users' locations to within a radius of about 200 km, but the new technique will narrow this down to 100 metres, a daily reports.

The development comes as privacy concerns were also raised about iPhone users having their locations and movements secretly tracked and stored.

Researchers discovered that the Apple devices save the user's latitude and longitude along with a time and date stamp that can be easily accessed.

The tracking method will allow online advertisers to target web browsers with tailored messages, but it has raised concerns about privacy.

Similar techniques of mapping the internet protocol (IP) address that every computer has are already in use, but are far less accurate.

The new system, which has been designed by American and Chinese researchers, compares the time it takes to send data to computers to the time it takes to send to computers it knows the location of using Google Maps.

Using a rough estimation of how far away the computer connection is, the system locates nearby landmarks, such as universities and schools, and compares their location to narrow down the computer's whereabouts.

On an average, the method gets to within 690 metres of the target, but it can be as close as 100 metres, good enough to identify the location of the computer to within a few streets.

To locate computers to this accuracy has previously required people to agree to share location, but the new system does not need any particular software on the computer to work or even the user's permission.

Yong Wang, one of the researchers who designed the method, said: 'This is a client-independent method. The client does not need to approve anything.'

The tracking system will be particularly valuable to advertisers who will be able to target browsers with advertisements for shops and service just down the street.

(Agencies)