Computer-enhanced, radar-enabled, global-satellite-positioned, they can see through 3 m of tarmac and earth to find exactly what's hiding under innocent-looking roads. Andy Pearson reports on a new breed of superhero.
The year: 2002
The location: Camchester, West Bartonshire

A white van draws to a halt alongside a busy main road. A man leaps out of the cab, strides purposefully round to the rear of vehicle, throws open the doors, grabs a handful of traffic cones and begins cordoning-off a section of the road. Task completed, the man returns to the van and clambers into the back.

Minutes later, he reappears pushing a small, wheel-mounted rectangular box. This time he is dressed in a white boilersuit. A belt around his waist supports a small computer-processing unit. Strapped to his left arm is the computer keyboard. A headset supports a computer screen the size of a postage stamp in front of his left eye. He snaps out commands to the computer, using a microphone suspended from the headset .

This is not avant-garde performance art; nor is it a scene from a future episode of Doctor Who.

It is the utility worker of the future going about his job. The wheeled box contains a radar transmitter, and when the unit is trundled up and down the road in parallel sweeps it can create a 3D image of the maze of cables, wires, pipes, ducts and drains buried beneath its surface. While the head-mounted display shows the operative what is buried in the ground up to 3 m below, a mini-satellite dish mounted on top of the unit tracks its position and provides the precise location for each of the pipes and cables.

Imagine a time when all road workers use this system before they start drilling. No slices through electricity cables, no phones falling dead as telephone cables are cut. And this day is not as far off as it might seem 鈥� the system has already been used on projects for gas distribution company Transco and for Yorkshire Water.

1. Headset
This contains the computer screen, an earpiece speaker and a microphone and can even support an integrated video camera. The screen can be positioned in front of either the user's left or right eye. Despite its miniscule size, the unit can display the same information as a normal desk-top sized monitor.

2. Belt-mounted computer
A battery-powered, shockproof unit contains the computer processor, built-in mouse and speech recognition software.

3. Radar unit
The wheeled unit contains the ground-penetrating radar and the unit's global positioning system. The radar provides a 3D map of the buried pipes and cables, while the GPS means that the unit remembers its position. This means that if a parked car blocks the survey area, the operative can return later and carry on the job where they left off. Also handy if you want a tea break.

Electromagnetic vision: how Utilityman can see through concrete

Called the Pathfinder, the radar unit can be used either to map the location and depths of buried services or to locate cables and pipes to avoid damaging them, for example, when digging a new pipe trench. US company Geophysical Survey Systems developed the unit for Rhurgas 鈥� a consortium of German gas companies 鈥� to help find plastic pipes. David Smale, a consultant to the equipment鈥檚 UK importer, Allied Associates Geophysical, says: 鈥淭he only sure way to detect buried plastic pipes is by using radar.鈥� The radar unit is pulled or pushed in parallel sweeps 0.25 m apart across the survey site. As the unit moves across the site, electromagnetic waves illuminate the ground 鈥渓ike a torch beam鈥�, says Smale. By running the sweeps a quarter of a metre apart, the scans overlap. The unit uses the overlap information to build up a detailed below-ground picture. The user鈥檚 heads-up display shows the position of each sweep as a series of dotted lines crossing the survey area. Once the survey has started, an arrow on screen shows which line of dots the radar is following, and a flashing square indicates the position of the radar unit. As the radar moves across the site, the display screen also shows the radar data being gathered as a series of sections through the ground. Once the site has been surveyed, the computer processes the radar information. It can then generate a 3D cube for the survey area showing the size, depth and location of all buried services. If required, this data can be downloaded onto an AutoCAD file to create an accurate drawing of the subsurface. One of the factors pushing the development of ground radar is the government鈥檚 proposal for a 鈥渓ane rental鈥� scheme, requiring utilities companies to pay 拢500 a day when they dig up roads. If a detailed survey has been done first, the work ought to be finished much sooner.