Beidou's accuracy has reached 3 cm

As China's independently developed and independently operated global satellite navigation system, the BeiDou satellite navigation system has always attracted wide attention. At the BeiDou Application Summit held in the past two days, the performance and application of BeiDou sparked heated discussions. Experts at the summit said that China's BeiDou precision index has exceeded GPS in some areas, and in terms of application, by 2016, the total number of BeiDou applications will exceed 30 million sets, achieving a breakthrough from one million to ten million, thereby reducing the cost of use.

The BeiDou Navigation Satellite System (BDS) is the world's third mature satellite navigation system after the United States' Global Positioning System (GPS) and Russia's GLONASS, providing positioning, navigation and timing services.

For satellite navigation systems, positioning accuracy is a key indicator of system performance. At present, the accuracy of the Beidou positioning system for civil services has reached 10 meters, while the latest generation of navigation chips can achieve a positioning accuracy of 2.5 meters, and the accuracy of the Beidou enhanced system at sea has been improved to 3 centimeters.

At yesterday's summit, a number of experts, including academicians of the Chinese Academy of Engineering, said that China's Beidou accuracy indicators have surpassed GPS in some local areas.

Wu Guanghui, chief designer of BeiDou application system, said: "This performance index has been mentioned by many experts just now, especially Academician Xu, who said that our index is generally on par with foreign GPS. In some areas, it exceeds the GPS positioning accuracy index, and in some local areas where our constellation composition is better, especially in terms of the number of satellites, geometric factors, and geometric configuration, ours may be better than the US GPS."

Regarding positioning accuracy, Li Donghang, director of the Consulting Center of the China Satellite Navigation and Positioning Association, elaborated on it from the perspective of the principles of the navigation system. He said that in China and the Asia-Pacific region, Beidou currently provides users with higher positioning accuracy.

"Beidou's domestic coverage and application are definitely better than GPS, because our satellite constellations are different. The satellites of the US GPS run back and forth over China, while we have five stationary satellites and five inclined-orbit satellites, which are always running over China and Asia-Pacific, and cover South Asia and part of the southern hemisphere. It can see more constellations and more positioning stars at any time." Li Wei, deputy director of the China Satellite Navigation and Positioning Application Management Center, said in an exclusive interview with our reporter that China is planning to build thousands of differential stations, which are expected to provide centimeter-level positioning accuracy in the future.

"GPS only provides 3 to 5 meters of service in China. Why is GPS so popular? Because there are many ground stations. In the case of ground station differential, the service they provide to users may be better. Now our Beidou system itself provides 2.5 meters, and we are also planning to have thousands of Beidou differential stations throughout China. When these stations are built, the accuracy we provide may be below the meter level, or even reach the centimeter level."

However, some industry insiders admit that navigation systems are dual-use. Today, in the civilian field, Beidou can already compete with other navigation systems in terms of performance, but there is still a gap in the military field.

Ma Zhenying, deputy manager of Beidou Business Unit of Guozhiheng Beidou Technology Group Co., Ltd., said that the navigation system is a complex system, and its performance is not only determined by the navigation system itself. For example, the key to the positioning accuracy of the navigation system lies in the accuracy of time. If we want Beidou to provide better positioning accuracy, we need to master more accurate time.

"The accuracy of positioning depends on time. The signal source and the time source are related. There is an atomic clock on the satellite. Why is China's accuracy still a little worse? This is the core component of satellite positioning."

Price is also a topic of concern. Ma Zhenying said that in terms of chips alone, the price of Beidou navigation chips is still higher than that of GPS chips.

"We can see that there are such modules on mobile phones. For example, GPS may only cost 2 US dollars. Beidou cannot make it so cheap. Now it is almost 100 RMB. Why can't Beidou make it so cheap? It's because the quantity is small."

According to the plan, by 2016, the total number of Beidou applications in China will exceed 30 million sets, achieving a breakthrough from one million to ten million sets, of which at least 20 million sets will be implemented on smart terminals. In this regard, Li Donghang, director of the Consulting Center of the China Satellite Navigation and Positioning Association, said that this will reduce the cost of using civilian Beidou chips.

"This plan is to rely on several mainstream domestic mobile terminal manufacturers to promote 20 million applications among the general public. We hope that the 20 million applications will quickly reduce the price level of our use of Beidou and Beidou components. Foreign chip manufacturers have hundreds of millions or even billions of users worldwide each year. The more they sell, the more profits they can make."

As a winner of Toutiao's Qingyun Plan and Baijiahao's Bai+ Plan, the 2019 Baidu Digital Author of the Year, the Baijiahao's Most Popular Author in the Technology Field, the 2019 Sogou Technology and Culture Author, and the 2021 Baijiahao Quarterly Influential Creator, he has won many awards, including the 2013 Sohu Best Industry Media Person, the 2015 China New Media Entrepreneurship Competition Beijing Third Place, the 2015 Guangmang Experience Award, the 2015 China New Media Entrepreneurship Competition Finals Third Place, and the 2018 Baidu Dynamic Annual Powerful Celebrity.