WHEN a thief jumped into an idling ice truck in Ang Mo Kio earlier this month, his proverbial goose was cooked even before he stepped on the gas.

The lorry may have vanished right before the eyes of its stunned driver, but it was being watched by an eye in the sky.

Like an increasing number of company-owned vehicles, it was hooked up to a satellite tracking system. That was how the police located and tracked the lorry.

Just 50 minutes after the drama began, the chase ended peacefully with the suspect nabbed and the lorry's owner singing the praises of satellite tracking.

"The global positioning system (GPS) helped us locate the truck almost immediately," said Mr Alex Goh, director of Uni-Tat Ice and Marketing.

In the past few years, tracking systems linked to global positioning satellites have been used to rescue taxi drivers from thugs, help car rental firms find stolen cars and ensure transport trucks get to their destinations on time.

This is possible because the technology uses satellites and receivers to pinpoint the vehicles' locations in real-time.

Ms Dorothy Chan, senior research manager at research firm IDC, said that GPS had become "fairly common".

"Chips are becoming smaller. The devices are also being embedded in cars and mobile phones to tell you where to go," she said.

Working on a chip as small as a fingernail, GPS devices can be fitted into mobile phones, wrist watches and on car dashboards.

Cost of the technology has also decreased, upping its appeal among companies with large fleets, such as taxi and car rental firms, and delivery companies.

According to Mr Carey Wee, chief adviser of home-grown tracking systems firm Asia Tracks, the cost of tracking a vehicle averages $80 a month now, compared with $140 three years ago.

The spectre of vehicle thefts pushed A1 Car Rental to lease a tracking system from Asia Tracks about a year ago, said operations manager Ken Low. It pays a monthly subscription of $60 to $70 for each of its 75 cars. The technology has already paid for itself, said Mr Low, since it has foiled at least five theft attempts.

The firm has also used satellite tracking to chase customers who had ignored their bills, and to sniff out overdue cars. The technology has even helped locate cars involved in an accident, including a recent five-car pile-up on the Pan Island Expressway where the driver was too shocked to say where he was.

Originally developed for military surveillance, satellite tracking has been embraced by delivery companies hauling everything from rice to chemical waste.

Combined with other technology such as radio tags, tracking systems can cough up data such as a truck's speed or distance travelled, which helps companies analyse their fleets' efficiency.

Similar technology has helped the Singapore Civil Defence Force (SCDF) keep an eye on tankers transporting hazardous materials. All trucks hauling the potentially deadly cargo must be equipped with immobilisers - equipment that can stop a vehicle in its tracks.

Through a $2 million system developed by location-based technology provider Astrata Asia Pacific, the SCDF can monitor and stop the trucks immediately if anything is amiss, to prevent terrorists from hijacking one and turning it into a giant bomb, for example. About 660 such vehicles here will be fitted with the system by April.

GPS has dozens of other uses.

Some school buses have trackers linked to special passes for students, so system operators know exactly where each child is and when he alights.

And GPS in some watches and cellphones can help runners navigate their routes and monitor their speeds. Companies are now working on improving the accuracy, so that they can pinpoint exact locations.

Ms Chan said: "Right now it's close enough, but not exact. For example, you can be in a certain place, but the system might be saying you are on the street nearby."

Finding lost children and nabbing molesters

JOSTLING with the rush-hour evening crowd at Toa Payoh bus interchange earlier this year, a mother discovered her three-year-old had disappeared.

"My child is missing. Please help me find my boy," the woman in her 30s, almost in tears, pleaded with SBS Transit route master Chua Aik Ngwen.

Embarking on a search, Mr Chua, 45, found commuters that had seen the boy boarding bus service 145, which goes to Buona Vista.

"When I heard that, I felt a great relief," he said in Hokkien.

He felt assured because SBS' satellite tracking system found out exactly where the likely buses were and contacted the drivers, one of whom had seen a crying boy on board.

The bus stopped at Lavender. The mother rushed there in a taxi with Mr Chua.

At a bus stop there, mother and child were reunited.

The satellite system is part of transport firm Comfort DelGro's fleet management systems for buses and taxis. Besides lost children, finding lost items and nabbing molesters are emergencies that the system has had to handle.