Feature

Positioning technology is not a lost cause

Glamorgan University tackles the shortcomings of GPS technology.

Hapless motorists and misguided ramblers need never be lost again if research being conducted at Glamorgan University comes to fruition. A team at the university is carrying out research into user positioning technology that addresses some of the weaknesses of conventional technology such as the satellite-based Global Positioning System, as used by in-car navigation systems.

George Taylor, the professor heading up the research team at Glamorgan University, said there are major issues over the accuracy and reliability of such data. A key problem is that a GPS receiver has to maintain "line of sight" with the satellites, and barriers such as buildings and trees often get in the way. Another issue is how many satellites are in sight and where they are - the more spread out they are, the more accurate the reading.

"Losing contact with satellites is a key problem. Your position can jump around quite a lot," said Taylor. "We are looking at ways of maintaining a position when that happens. Also, GPS is often 10m-15m out, and that could place you in the wrong street."

The basic idea behind Glamorgan University's research is to take GPS and make it more reliable by combining it with other technology such as GIS (geographic information systems), which translate geographic data such as street addresses into a map location. A key focus is comparing and matching GPS data with the Ordnance Survey's detailed digital mapping database, which Taylor calls "a model of the UK inside a computer".

Taylor's team aims to create a standalone system that uses digital mapping data and will eventually function without GPS, while providing more reliable, continuous and accurate positioning of devices, including mobile phones and personal digital assistants. However, the initial focus is on in-car systems.

GPS and GIS can show to within 15m or so where the device is. By matching this information with the digital mapping data, the system can more accurately predict what road the user is on. The university is also using artificial neural network techniques for this purpose. These techniques simulate the type of processes that go on in the brain and can be trained, using set parameters and thousands of scenarios, to help predict where the user is and can show how confident the system is of its conclusions.

Preliminary tests using this technique demonstrated a 10% improvement in accuracy and the university now has a full-time research student conducting work in this area. "It is pretty exciting really - I think we will get some good results," said Taylor.

The research team is also using geographical information to reduce the number of satellites required to calculate location with global navigation satellite systems. Taylor explained that to get a proper 3D reading with GPS you need to be in the line of sight of four satellites, or three for a 2D image. The university is looking at ways of cutting down on this number, for example by using the centre of the earth as a replacement for a satellite to give height readings.

One business application of positioning techniques is location-based services. Taylor believes there is "a fundamental need" for such services. However, while location-based services have been hotly tipped as an emerging technology for the past few years, the substance has not yet matched the hype. Short of trials involving shoppers being "zapped" special offers on their mobiles as they pass stores in shopping centres such as Bluewater, very little has happened.

A key issue is accuracy. "You only have to be 5m out and you get the wrong information," said Taylor. "People just switch the service off because it is rubbish." One problem is that shopping malls have roofs, which block GPS signals.

Taylor predicted there will be a myriad of potential applications for the technology Glamorgan University is developing. One interested party is the Welsh Museum of Life, which is "very keen" to use the technology to provide location-specific information to visitors in place of the current audio headset-based system.

The university is also part of the Musika research project, which aims to develop software that will help developers write applications for the European civilian satellite project Galileo, which is due to enter service from 2006. Galileo will address problems with the existing GPS, which is controlled by the US military.

A key problem is that during wartime the military can move the satellites to a new location or even turn them off entirely. "You cannot build applications that are safety-specific on a system that could be switched off," Taylor said.

A key development will be the mass take up of third generation mobile phones, which will provide the increased bandwidth to support location-based services. Other technology such as Bluetooth and "pseudo-lites" - fixed-position terrestrial satellite dishes that can be attached to buildings - could also help kickstart this technology and help bring the benefits of GPS and Galileo indoors.

"The requirement for very accurate positioning that is both reliable and continuous will be on the increase almost forever," said Taylor. "I see a time when these devices will be so small they will be sewn into your clothes. The future is a world where anyone with a PDA or mobile phone loaded with the right software could never get lost, and would always know what they were looking at."


Potential applications

Interactive tour guides

Providing visitors to tourist attractions with information on the item they are looking at, such as a painting or building, or a list of local hotels and restaurants.

Navigation for the blind

Mobile devices with digital mapping software could activated by voice commands or a keypad.

Reducing traffic accidents

Drivers could get warnings if their car is veering off the road. "In the future, you will have totally automatic cars - cars that can even park themselves," said Taylor. "That is 20 to 30 years away."

Engineering

Positioning roads and structures.



CV: George Taylor

George Taylor's current research interests focus on the integration of geographical information systems with satellite navigation systems, such as the Global Positioning System. During the past 10 years he has worked on many projects involving modelling spatial phenomena and applying digital map data to large-scale geographical information problems. Much of his research work has been in collaboration with industrial partners, leading to commercially marketable geographical information products.

www.comp.glam.ac.uk/pages/staff/getaylor/index.htm



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This was first published in June 2003

 

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