"The GPS is not always accurate, but it' s helpful for those who don't know how to read a map, or use compass or who can't see the sun," says Pan, an outdoors enthusiast who bought a hand-held GPS two years ago.

The GPS is the most advanced system of its kind in the world, even though it has some problems. Europe, Russia and China are developing their own satellite navigation systems. "We will see more progress and competition among Europe's Galileo, China's Compass and Russia's Glonass systems," says Zeng Jianqiu, a professor from the Beijing University of Post and Telecommunications.

Chen Jiancheng, a senior advisor for China Top Communication Company, which provides products and services of China's own Compass satellite navigation system, points out that GPS occupies more than 95 percent of China's satellite navigation market.

"The GPS has been used in many fields like surveying and mapping," Chen says. "We don't just need navigation - we need safe navigation. In key areas, we should use our own satellite navigation system to ensure national security."

For this very reason, on Jan. 17, China launched its third Compass navigation satellite.

Before the construction of the Compass navigation system, China sent four experimental navigation satellites into orbit from 2000 to 2007 to form the experimental system, known as Beidou ("Big Dipper"). The Beidou system covers China only. The government expects the Compass system, jointly developed by state-owned aerospace and electronics departments, to rival GPS to cover the world after it is completed.

Zhao Kangning, deputy director of the China National Administration of GNSS (Global Navigation Satellite Systems) and Applications, says "The Compass system is going to provide positioning and navigation services to China and the Asia-Pacific region by 2012."

Meanwhile, he says, China will expand the Compass system into a global network, requiring at least 30 satellites, by 2020.

Currently, the accuracy of the Compass is not as reliable as the GPS system.

Zhao says the accuracy of Compass in Beijing comes to within about 10 meters, and within about 20 meters in south China. The accuracy is dropping to within 50 meters at sea.

"When we provide regional services, the accuracy is expected to be within 10 meters. And when Compass is expanded into a global system, the accuracy can be improved," Zhao says.

Yet, Compass has one unique advantage - sending text messages. When the May 12 earthquake devastated southwest China's Sichuan Province in 2008, the system helped the army navigate in the disaster area and offered message communication services in areas where all other communications were destroyed.

Quake survivor Yang Xue recalled she was separated from her husband after the earthquake. She trekked for six hours in the mountains to reach safety.

However, the region has no mobile phone signal. Yang didn't know whether her husband was still alive. As she desperately sought information, she met the army carrying Compass terminals. They helped her send messages to both the rescue headquarters and her husband's mobile phone.

With the help of Compass, Yang finally found her husband, and reunited with her family.

In the month after the quake, the Compass system had been used for positioning and navigation 1.64 million times in the disaster area, and sent 740,000 text messages, says Zhao Kangning.

The Compass positioning and navigation system has also been used in the recovery of the Shenzhou-7 spacecraft; monitoring dangerous chemical transport; and guiding traffic and monitoring sports venues during the Beijing Olympic Games in 2008.

Zhao says more than 30 Chinese companies are producing more than 20 Compass-related products.

The Compass system has more than 40,000 registered clients, mainly from the fields of water conservancy projects, marine fishery, transport, meteorology, surveying and mapping and disaster relief. The number of clients is expected to double by the end of 2010.

However, some question the future market of the Compass system.

Hong Tao, a technician with a Beijing company that sells GPS products, says, "I pay close attention to the development of the Compass system. I don't think it can challenge the monopoly status of the GPS in the near future.

"GPS has occupied the market for a long time. People are already used to GPS. It will take a long time for customers to accept a new product, no matter how good it is."

Chen Jiancheng, who works for a company that develops and sells Compass products, admits Compass is not yet as convenient as GPS, and it costs four to five times more than GPS.

He explains that the Compass system is still at a preliminary stage, and the number of clients is very small. "Only mass production and usage can lower the price of the system."

He wants the government to implement preferential policies to encourage research on and development of Compass products and to lower the costs.

"While we don't reject foreign satellite navigation and positioning systems, the government should require key departments to use China's own Compass system, in order to ensure national security and promote the development of our own satellite navigation and positioning system," Chen says.

As for the relationship between GPS and Compass, Zhao Kangning says they are rivals and cooperators at the same time.

Chinese Compass technologists have held talks with counterparts from GPS in the United States to negotiate about future cooperation between the two systems, Zhao says, adding that the U.S. side showed willingness to cooperate.

"The Compass system is designed to be compatible with other systems. In future, Compass terminals will not only receive the signals from Compass, but also from the GPS and other satellite navigation systems," Zhao says.

In other words, when one system has a problem, "you can be directed by other systems. You can always know where you are and where you are going."

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