The "Statement" pointed out that Beidou satellite navigation system and GPS global satellite navigation system to achieve RF compatibility under the framework of the ITU, two systems civilian signals B1C and L1C to achieve interoperability.Users can use both Beidou and GPS civil signals at the same time, and enjoy better service without significant cost increases.
According to Lu Xiaochun, according to the working principle of satellite navigation system, the receiver needs to "see" at least four navigation satellites in order to achieve positioning. With a single navigation system, the number of satellites in a given area may be limited and insufficiently redundant. Once the receiver is disconnected from a certain satellite, the continuity of the positioning service may be affected. After BeiDou interoperates with GPS, users can simultaneously receive two satellite signals from one receiver. The number of GPS satellites is not enough, and there are Beidou satellites. The stability and precision of positioning will be higher.
In short, through signal compatibility, it is equivalent to integrating the original navigation system into a large system. At present, China and Russia are also promoting the interoperability and compatibility of BeiDou and GLONASS systems. They have conducted many talks and achieved good results. Whether from the needs of users or the development of satellite navigation systems, cooperation is the trend of the times.
Xiao-Chun Lu introduced, in addition to the signal, satellite navigation system compatible coordination also includes many aspects.
For example, frequency resources. Lu Xiao-chun said that the frequency of satellite navigation required by the ITU must be within a limited range of the L-band, first come first served. In the initial development of satellite navigation system, GPS dominance, occupy most of the band. Glonass also takes up a part. Compass started late, the remaining frequency resources are extremely limited, in accordance with the rules of ITU, with the first to consult. By the end of 2015, China and the United States reached an agreement that Beidou can share frequency resources without affecting the frequency band in which GPS signals are sent.
At the same time, navigation satellites are subject to orbital resource constraints, so there are compatibility issues with the constellation orbit. In addition, each navigation system's time system, coordinate system needs to achieve compatible interoperability.
In 2006, the United Nations set up the International Committee on Global Navigation Satellite System to aim at coordinating the compatibility and interoperability of satellite navigation systems and promoting cooperation and development. Based on this platform, Beidou actively cooperates with other navigation systems.
Lu Xiaochun introduced,In January 2018, Beidou and GPS will hold the third round of talks in our country and continue to promote cooperation between the two sides."For this reason, we have set up 4 working groups for compatibility and interoperability, star-based enhancement, monitoring and evaluation of service performance and application." She said, "If there is a new intention and direction for cooperation, we will also Continue to follow up. "