三、提供可靠安全的卫星导航服务
中国承诺采取多项措施保障系统安全稳定运行，为用户免费提供连续、稳定、可靠的公开服务。
（一）保障北斗系统安全稳定运行
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
——完善运行管理机制。完善北斗系统空间段、地面段、用户段的多方联动的常态化机制，不断提高大型星座系统的运行管理保障能力。
——建立监测评估网络。建设全球连续监测评估系统，积极开展国际合作，广泛利用国际资源，对北斗系统星座状态、信号精度、信号质量和系统服务性能等进行全方位的监测和评估，为用户应用提供参考。
- 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.
——采取冗余备份手段。采用卫星在轨、地面备份策略，避免和降低卫星突发在轨故障对系统服务性能的影响；采用地面设施的冗余备份设计，着力消除薄弱环节，增强系统可靠性。
（二）提供免费的公开服务
目前，正在运行的北斗二号系统发播B1I和B2I公开服务信号，免费向亚太地区提供公开服务。服务区为南北纬55度、东经55度到180度区域，定位精度优于10米，测速精度优于0.2米/秒，授时精度优于50纳秒。
- 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.
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