In the concrete canyons of city centres, GPS satellite positioning systems often fail because high buildings block the signals they rely on. But an unlikely back-up for GPS is emerging: Wi-Fi. A Wi-Fi based positioning system developed in the US and the UK works best where GPS fails: in cities and inside cavernous complexes like shopping malls. And because cheap Wi-Fi technology is already appearing on a raft of gadgets like PDAs, cellphones and laptops faster than more expensive GPS receivers are, the developers predict that Wi-Fi could become central to new location-based applications.
They say emergency services in particular could find the system an essential back-up. Wi-Fi allows people to connect devices wirelessly to the internet. Base stations are springing up in coffee bars, libraries, universities, airports, phone booths and other public places. Each base station broadcasts a radio signal to announce its presence to devices within a range of around 100 metres. This signal incorporates a unique network address code that identifies the base station. Anthony LaMarca of the University of Washington in Seattle, and colleagues at Intel’s research labs in both the US and the UK, have developed software that constantly records the radio signal strengths from nearby base stations. It can identify the origin of the signal from a database giving the location of 26,000 Wi-Fi base stations in the US and the UK. Using the signal strength from at least three base stations, it can then triangulate the user’s location. "This is a poor man’s GPS," says team member Bill Schilit of Intel Research in Santa Clara, California.
At the moment, the new system, called Place Lab, is not as precise as GPS. It can provide accuracy to within 20 to 30 metres, whereas the GPS average is 8 to 10 metres. But with improved algorithms that take into account, say, the height of the base station above the ground, or the building materials in the vicinity, LaMarca says "we could get on a par with GPS" in an area as densely served with Wi-Fi as downtown Seattle. The growth of Wi-Fi means all urban areas should one day have similar blanket coverage. Once a user has Wi-Fi they won’t have to buy extra hardware to use Place Lab, and the software can be downloaded for free from http://www.placelab.org. Increasingly, laptops, cellphones and PDAs are being sold with Wi-Fi capability already installed for around an extra $30. "This is not the case with GPS," LaMarca points out.
Accelerating quantum technologies with materials processing at the atomic scale
15.05.2019 | University of Oxford
A step towards probabilistic computing
15.05.2019 | University of Konstanz
Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.
The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...
Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...
With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.
Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...
'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.
However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...
Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future
When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
23.05.2019 | Materials Sciences
23.05.2019 | Materials Sciences
23.05.2019 | Physics and Astronomy