III. Reliable and Safe Satellite Navigation Services
China is committed to ensuring the safe and reliable operation of the BDS by taking multiple measures, and to providing continuous, stable and reliable open services to users free of charge.
(I) Ensuring Safe and Reliable BDS Operations
- Improving the management mechanism on operation. Perfecting a normalized multi-party response mechanism for BDS space segment, ground segment and user segment. Continuously enhancing the capability of assurance to manage the operation of large-scale constellations.
- Establishing a GNSS monitoring and assessment network. Constructing an international GNSS Monitoring and Assessment System, actively implementing international cooperation, extensively exploiting international resources, carrying out monitoring and assessment of the constellation status, signal accuracy, signal quality and service performance of the BDS at every scale, and providing references for users' applications.
- Taking a redundant and backup approach. Adopting a satellite backup strategy both in-orbit and on-ground to reduce and avoid the effects of emergent in-orbit satellite fault affecting service performance. Redundant and backup design is adopted to enable ground facilities to eliminate weak links, and to enhance BDS reliability.
(II) Providing Open Services Free of Charge
Currently, B1I and B2I open service signals are being broadcast by the operating BDS-2 to provide open services to the Asia-Pacific region free of charge. The services cover an area extending 55 degrees North-55 degrees South and 55 degrees East-180 degrees East, with positioning accuracy less than 10 meters, velocity measurement accuracy less than 0.2 meter per second, and timing accuracy less than 50 nanoseconds.
(III) Disseminating BDS Information in a Timely Manner
- Publishing BDS documents related to open services and signals to provide inputs for global BDS product development efforts. The Interface Control Document of B1I and B2I signals has been published, which defines the interface specifications between the BDS-2 satellites and user terminals. It specifies the signal structures, basic characteristics, ranging codes, NAV messages and other contents. The Open Service Performance Standard has been published, which defines the service coverage area, accuracy, continuity, availability, and other performance indexes of the BDS-2. In the future, related documents will be updated and published in step with BDS construction and development.
- Establishing a multi-channel information dissemination mechanism. China holds news conferences when appropriate to disseminate important information about BDS development, and releases the latest news of the system in a timely manner through the official BDS website (www.beidou.gov.cn) from the aspects of system construction, operation, application, and international cooperation. It also issues notifications worldwide in advance before carrying out plans which might affect user services.
(IV) Protecting the Utilization of Radio-Navigation Satellite Frequency Spectrum
- Protecting the radio-navigation satellite frequency spectrum according to law. China protects the utilization of BDS frequency spectrum, and ensures the safety of BDS operation and BDS users pursuant to the national laws and regulations regarding the radio frequency spectrum.
- Firmly rejecting harmful interference. China prohibits the production, sale and use of illegal interference devices, investigates and punishes in accordance with the law any hostile interference actions which affect the system operations and services.
