Cell phones pinpoint locations (2)

As a result, life can be made more convenient, such as through live monitoring of traffic congestion or monitoring dangerous and poisonous goods.

However, nothing can be accomplished without a highly accurate positioning system.

Paul Zandbergen, an associate professor with the University of New Mexico's geography department, carried out an accuracy survey on positioning systems on the 3G iPhone in 2009.

Results showed Wi-Fi locations using this phone had an average error of 74 meters for 58 observations, failing to meet the published accuracy specifications, while cellular positioning using this phone had a median error of 600 meters for 64 observations.

"Most pointing devices can pinpoint positions within 10 meters. But if we can improve the accuracy to less than a meter, it means we can accomplish many tasks that were not possible without a high-accuracy system," Shi said.

On Oct 9, China's National Remote Sensing Center said a new navigation system, Xihe, had been successfully tested to pinpoint positions within 0.1 meters outdoors and 3 meters indoors.

The system benefits business owners like Cao Hongjie, vice-president of Beijing UniStrong Science and Technology, a maker of navigation products.

"In the past, we designed different circuit boards for clients having different demands for the precision, but with Xihe, the precision difference can be controlled in operation centers, and we can use a device that applies to Xihe to provide services with different accuracy," Cao said.

For example, during China's last land survey, UniStrong designed several devices because accuracy requirements in eastern and western parts of the county vary by up to 50 times.

Cao said the device that sold best and which cost 15,000 yuan ($2,400) had an error factor of less than 5 cm. "But now I have developed a new version of the land survey device using the Xihe system, which is as good as the former and I'm planning to sell it for up to 8,000 yuan," he said.

"The new technology lowers the price, but gives me even more room for profit."