Two-way street
Currently, there are four Global Navigation Satellite Systems, BDS, GPS, GLONASS and Europe's Galileo. BDS has some design advantages.
Tan said that BeiDou will eventually be able to realize higher accuracy as its service can broadcast on three frequencies, unlike the GPS, which only uses one.
In addition, unlike other systems which only broadcast one-way reference signals, BDS has a two-way communication capability that allows users to send short text messages.
For example, a general can use BDS to send instructions to his soldiers, and fishing boats that break down can call for help without using unreliable mobile phone signals or expensive marine satellite Internet.
"After the signal is received, staff at the operation center will find out whether there are other boats nearby, and then carry out a rescue operation as soon as possible," Zhou Ruxin, member of staff at the Beidou Operation Service Center, was quoted as saying by China Central Television.
According to an article written last year by someone working at a military-industry unit who used the pseudonym "Donnie," sending a short message via BeiDou only costs 0.3 yuan ($0.04), much less than using a satellite telephone.
Donnie cited 2011 statistics that said fishermen in East China's Zhejiang Province sent a total of 13 million short messages through BDS that year.
Guo Zhiguo from Ala Farm explained that the BDS collars they attach to animals send positioning messages automatically more than 20 times a day and the device's battery can last for 16 months.
"Before, we negotiated with a company that used GPS, but their collars cost up to 10,000 yuan. The BDS collars only cost about 80 yuan each," Guo told the Global Times.
He believes that besides helping farmers, they can be of assistance to the government. "The government can have access to the database, so they can easily monitor cattle numbers and respond if the density is too high," he said.
Guo said Ala Farm has helped farmers collar over 1,000 sheep so far. However, he is highly ambitious and expects to one day provide 100,000 collars annually.
"Many herdsmen from Tibet, Qinghai and Xinjiang have approached me and asked to join in," he said.
Finding the path
However, despite its growing popularity, the BeiDou satellite network has some shortcomings.
The performance of the BeiDou System, such as its accuracy, still needs to be improved.
A young man in Beijing told the Global Times that he used a BeiDou wristwatch during a hike about three years ago. "It was disappointing that the data it showed on positioning and altitude were both inaccurate," he said.
However, Ma Deming, an outdoor brand consultant, doesn't think BDS's performance lags much behind GPS today. He co-organized a cross-country run that circled Mount Siguniang, Sichuan Province, in November last year. The organizer put a BDS/GPS dual-mode device on runners, making it the first cross-country running event to use BDS, he said.
"BDS performs well in positioning accuracy and two-way communication. I believe the BDS will have a bright prospect in risk and safety management in activities like wildness exploration, trail running and rescue," Ma told the Global Times.
But Xu Qifeng, an expert on global navigation satellites, pointed out that BDS will face major hurdles to going global.
To increase accuracy and realize global coverage, BDS monitoring stations will need to be established globally.
According to gps.gov, there are 350 GPS monitoring stations in 80 countries, contributing to an international network of navigation services.
"But it's a big challenge for China to build so many monitoring stations overseas," Xu remarked at the 7th China Satellite Navigation Conference, citing the huge cost.
Besides, China's satellite atomic clock technology, which is vital for the accuracy of the system's service, lags behind the U.S.' and Europe's, Xu lamented at a navigation forum in 2012.
Tan said he agrees with Xu. "There's a lot for us to do, such as negotiating with other countries in both diplomatic and civilian means," Tan told the Global Times.
"BDS's general positioning effect is still inferior to GPS's. The terminal chips we've made are diversified and some of them are already small enough, but there is still gap on average," Tan said.
Li Yuan, a senior manager with the MXTronics Corporation, which produced BDS collars to help track Tibetan antelopes in 2013, said the gap is understandable as the GPS has been established for decades.
The space, ground and user stations for BDS are yet to be completely established. When fully deployed, the BDS space network will consist of five Geostationary Earth Orbit satellites, 27 Medium Earth Orbit satellites and three Inclined Geosynchronous Satellite Orbit satellites.
So far, a total of 22 satellites have been launched. Ran Chengqi, director of the China Satellite Navigation Office, said in May that there are plans to launch another BeiDou satellite this year. By 2018, China is excepted to offer services to all the countries involved in the One Belt and One Road initiative.
The other three Global Navigation Satellite Systems are also preparing to expand or update their constellations by launching next-generation satellites.
Li Runsheng is confident about BDS. He is prepared, with BDS's help, to expand his flock.
According to official statistics, the gross revenue from navigation satellites in China reached 190 billion yuan last year, 30 percent of which was contributed by BDS-enabled products.
