NAVTEQ

The rise in the popularity of PDA-based navigation systems seems unstoppable, and every year more people turn to electronic maps to find their way around Britain and Europe. But what’s involved ingathering all this information, and how do you ensure it’s accurate enough to get from John O’Groats to central London without getting lost?

In-car navigation systems are popular additions to luxury cars, but they have two big drawbacks. Firstly, you can’t use them outside the vehicle and secondly, the hardware can’t be used for any other task. Step forward the humble PDA. Not only can it run all kinds of software, but you can also use the device to navigate on foot or in another vehicle. It’s an ideal application to harness the power and flexibility of a modern PDA.

The technology involved in monitoring satellites to determine your position, speed and direction of travel is impressive enough, but it’s almost unbelievable that the entire map of Britain can be held on a single 128MB memory card. A map that includes street names and house numbers, the locations of cash machines and petrol stations, and even which streets are part of London’s congestion charge zone. And whether or not you get lost rests largely on the quality of the information used to create the maps. After all, there’s little value to data that’s not accurate or continually updated. Just imagine if your navigation instructions took you the wrong way along a one-way street.

ROAD BUILDING

To find out exactly how it’s done we spent a day with Navteq Technologies (previously called Navtech). Rather than providing end-user GPS systems, it supplies the map and navigation data that other companies use in building their products. Graham Ward, Navteq’s country manager UK & Ireland, explains: “The Navteq database provides hierarchical layers of topographical and geographical information down to street level detail. By adding attributes – the information needed in order to ascertain who can use a particular stretch of road, in what direction, in what type of vehicle, at what time and at what speed – it becomes navigable.”

Third-party companies overlay calculation functions and user friendly designs, creating diverse products, such as Garmin’s iQue 3600, the Internet’s MapQuest website (www.mapquest.com) and BMW in-car navigation systems. “The digital map database is the foundation of any navigation system on which the third-party software developer builds, by adding the final look plus software for both route calculation and interpreting the GPS position on the map display,” says Ward.

It has taken five years to build the database for Great Britain alone. Information can be gathered from a wide range of sources, but the starting point is to use what’s already in existence, including Ordnance Survey data, aerial photography and postcode locations. However, although this provides a basic platform, it lacks the features required for GPS navigation. Then Navteq visited every local authority in the country to wade through decades of paperwork. With the exception of motorways, which are handled by the Highways Agency, local authorities determine changes to roads. For example, layouts for new roads, and changes to existing ones, including one-way systems, parking restrictions, pedestrian zones and traffic calming humps.

“We had to visit hundreds of local authority offices across the country and read through every traffic order created since they started in the 1930s,” says Ward. “Once we collated this information, it was all checked on the ground by our field researchers. “Bearing in mind a significant percentage of the road network changes every year, the map database is continually updated and verified. Just because a new one-way system is planned doesn’t mean it will be completed on schedule.”

DRIVE TIME

In the end, it comes down to researchers getting into cars and literally driving the country. Standard vehicles are used with roof mounted OmniSTAR differential GPS receivers. With an accuracy of 1m, this system is much more precise than consumer receivers. Instead of relying solely on orbiting satellites, a differential system(DGPS) also uses fixed sources to compare results and correct errors, such as those caused by atmospheric conditions. The OmniStar’s gyroscope also combats ‘urban canyons’ – built-up areas where tall buildings obscure the satellites reception.

The receiver is connected to a laptop running Navteq’s database for the surrounding area. Data collection is a two-person job: one to drive the car and an observer to operate the laptop. The screen shows the GPS location on a wire map, and the observer makes sure that what’s seen out of the car window is recorded accurately on the plot.

A game-pad provides the ideal console to control the software and besides zooming it allows the observer to drop voice notes onto the map using a headset. “The non-driver talks to the laptop via a headset, noting all the changes as they travel the roads – including everything from a ‘no entry’ sign to a new housing estate,” explains Ward. “Each sound file is then automatically linked to the appropriate place on the map database. By using voice annotations, they can keep their eyes on the streets rather than looking at a keyboard.”

The notes can also be used to add points of interest (POI),such as cash point machines, restaurants and petrol stations, so users can find these important resources when travelling. Finally, the laptops are returned to the office and the live database is updated. Navteq’s 28 UK-based researchers have catalogued 442,000km of roads, divided into 2.9m ‘links’ between intersections. Each link holds up to 150 attributes, such as the type of road, speed category, house number range, condition and so on, with 435 million attributes for the UK and Ireland.

THE WORLD’S YOUR OYSTER

POIs will become increasingly important as the long-promised location-based services become a reality, and there are currently more than 65,000 UK POIs catalogued in 44 categories. Similar databases exist for the US and much of Europe, and projects are under way surveying Scandinavia and Asia. The initial five-year process for mainland Britain was completed in1999, and the Republic of Ireland is scheduled for 2005.For the user, having up-to-date maps is vitally important.

Car systems commonly use CDs for updates and PDAs use fresh maps downloaded via a computer. Although Navteq issues data updates quarterly, it relies on third-party suppliers to distribute new maps and users to install them. This might seem inconvenient, but increasing Internet and Wi-Fi connectivity will solve this. Navteq’s database supports partial updates, and developers are likely to follow suit to provide systems akin to synchronisation, where users download the latest changes before a journey starts.

SAT-NAV IN A NUTSHELL

GPS navigation systems tune in to a network of 24 satellites orbiting the earth, using the signals to calculate position, direction of travel and speed. In this line-of-sight system, at least three satellites must be ‘visible’ in the sky above to triangulate position, but a fourth is required for complete accuracy and to determine altitude.

Garmin iQue 3600
GPS manufacturer Garmin is well known for it’s range of dedicated hand-held GPS receivers, but with the iQue 3600 (£586 inc. VAT) the company has blended three elements into one device – PDA, GPS receiver and navigation software. The handheld runs on Palm OS, and operates like any standard Palm PDA. However, by extending a fold-away antenna on the back of the device, it becomes a fully functional GPS navigator based upon Navteq data. This all-in-one approach means you only need to carry a single piece of hardware.

PRICE: £499/£586 (EX/INC. VAT)

OS: PALM OS 5
DIMENSIONS: 127 X 71 X 19MM
WEIGHT: 170G
CONTACT: 0870 850 1242 WWW.GARMIN.COM

Evesham Mio 168
Global Positioning System Pocket PC fans shouldn’t worry that they’ve been left behind, because Evesham offers the Mio 168 (£450 inc. VAT), a PocketPC equivalent of the Garmin iQue 3600. However, unlike the Garmin, it’s not a custom-developed solution, but a convenient bundle of hardware and navigation software. he Mio 168operates as a standard PDA, but with a fold-out antenna on the rear of the device. It’s supplied with CoPilotLive Pocket PC 4 software, a solution from ALK Technologies that also uses Navteq data. CoPilot Live also includes a laptop module for route planning on the desktop.

PRICE: £382/£450 (EX/INC. VAT)

OS: MOBILE WINDOWS FOR POCKET PC 2003
DIMENSIONS: 111 X 69 X 24MM
WEIGHT: 155G
CONTACT: 0870 160 9500 WWW.EVESHAM.COM