01
What are the versions of the BeiDou Navigation Satellite System Interface Control Document?
At present, the official website of BeiDou Navigation Satellite System has publicly released 9 versions of Interface Control Document, which are "BeiDou Navigation Satellite System Ground-based Augmentation Service Interface Control Document (Version 1.0)","BeiDou Navigation Satellite System Signal In Space Interface Control Document Search and Rescue Service (Version 1.0)","BeiDou Navigation Satellite System Signal In Space Interface Control Document Satellite Based Augmentation System Service Signal BDSBAS-B1C (Version 1.0)","BeiDou Navigation Satellite System Signal In Space Interface Control Document Precise Point Positioning Service Signal PPP-B2b (Version 1.0)","BeiDou Navigation Satellite System Signal In Space Interface Control Document Open Service Signal B2b (Version 1.0)","BeiDou Navigation Satellite System Signal In Space Interface Control Document Open Service Signal B1I (Version 3.0)","BeiDou Navigation Satellite System Signal In Space Interface Control Document Open Service Signal B1C (Version 1.0)","BeiDou Navigation Satellite System Signal In Space Interface Control Document Open Service Signal B2a (Version 1.0)","BeiDou Navigation Satellite System Signal In Space Interface Control Document Open Service Signal B3I (Version 1.0)", and the first 5 versions are the latest versions released in July 2020。
02
What are the versions of the BeiDou Navigation Satellite System Open Service Performance Standard?
At present, the official website of BeiDou Navigation Satellite System has publicly released 3 versions of Open Service Performance Standard, which are "BeiDou Navigation Satellite System Open Service Performance Standard (Version 3.0)","BeiDou Navigation Satellite System Open Service Performance Standard (Version 2.0)","BeiDou Navigation Satellite System Open Service Performance Standard (Version 1.0)", and the version 3.0 is the latest version released in May 2021.
03
How to download the Interface Control Document and Open Service Performance Standard of BeiDou Navigation Satellite System?
The BeiDou Navigation Satellite System's official website www.beidou.gov.cn is the only official release channel for the BeiDou Navigation Satellite System Interface Control Document(ICD). Any enterprise and individual can download it on the website. As a professional research institution under the China Satellite Navigation System Management Office, our center also provides a backup download function on the website, but all relevant information should be based on the official website of BeiDou Navigation Satellite System.
04
The introduction to the preparation unit of BeiDou Navigation Satellite System Interface Control Document.
The BeiDou Navigation Satellite System Interface Control Document is compiled by the Test and Assessment Research Center (TARC) of China Satellite Navigation Office. Test and Assessment Research Center (TARC) of China Satellite Navigation Office is a professional research institution specialized in satellite navigation technology. It was jointly established by China Satellite Navigation Office (CSNO) and China Aerospace Science and Technology Corporation (CASC) in 2011. The research center plays an important role in system construction and operation service of BeiDou Navigation Satellite System (BDS). Major responsibilities include the construction and operation of International GNSS Monitoring & Assessment System (iGMAS), includes the development of system tracking stations and the construction of other fundamental infrastructures, the maintenance and management of system daily operation; the construction and operation of BDS Ground Simulation and Verification System, includes system integration, planning and implementation phase of simulation test; Provide BDS user support, including the information of system operation status and service performance, and the reply to user feedbacks; Carry out international cooperation in BDS test and assessment & civil service field, and promote the application of BDS on a global scale.
05
The constellation of BeiDou Navigation Satellite System.
The BDS-3 nominal constellation consists of 3 GEO satellites, 3 IGSO satellites, and 24 MEO satellites. The GEO satellites operate in the orbits at an altitude of 35,786 kilometers and are located at 80°E, 110.5°E, and 140°E respectively. The IGSO satellites operate in the orbits at an altitude of 35,786 kilometers and an inclination of the orbital planes of 55° with reference to the equatorial plane. The MEO satellites operate in the orbits at an altitude of 21,528 kilometers and an inclination of the orbital planes of 55°with reference to the equatorial plane, and are distributed in a Walker24/3/1 constellation. On-orbit backup satellites will be deployed as needed
06
The service performance standard of BeiDou Navigation Satellite System.
BDS-3 provides various services, including positioning, navigation, timing, global short message communication, and international search and rescue services for global users, as well as the satellite-based augmentation, ground augmentation, precise point positioning and regional short message communication services for users in China and surrounding areas. The positioning accuracy standard is below 9m horizontal, and below 10m vertical. The velocity measurement accuracy standard is below 0.2m/s.The timing accuracy standard is below 20ns。
07
The signal characteristics of BeiDou Navigation Satellite System.
BDS-2 provides B1I, B2I and B3I three public service signals in the three frequency bands of B1, B2 and B3. The center frequency of B1 is 1561.098MHz, B2 is 1207.140MHz, B3 is 1268.520MHz.
BDS-3 provides B1I, B1C, B2a, B2b and B3I public service signals in the three frequency bands of B1, B2 and B3. The center frequency of B1I is 1561.098MHz, B1C is 1575.420MHz, B2a is 1176.450MHz, B2b is 1207.14MHz, B3 is 1268.520MHz.
08
The coordinate system and time system of BeiDou Navigation Satellite System.
BDS adopts the BeiDou Coordinate System (BDCS) whose definition complies with the standards of the International Earth Rotation and Reference System Service(IERS). The definition is also consistent with that of the China Geodetic Coordinate System 2000(CGCS2000). BDCS and CGCS2000 have the same ellipsoid parameters.
The BeiDou Navigation Satellite System Time (BDT) is adopted by the BDS as time reference. BDT adopts the second of the international system of units (SI) as the base unit, and accumulates continuously without leap seconds. The start epoch of BDT is 00:00:00 on January 1, 2006 of Coordinated Universal Time (UTC). BDT connects with UTC via UTC (NTSC), and the deviation of BDT to UTC is maintained within 50 nanoseconds (modulo 1 second).
09
The construction process and later plan of BeiDou Navigation Satellite System.
The BeiDou Navigation Satellite System (BDS) has been built and developed in accordance with a "three-step" strategy. BDS-1 construction was started from 1994 and put into use in 2000. It adopted an active positioning scheme to provide Chinese users with positioning, timing, wide-area differential and short message communication services. BDS-2 construction was started from 2004 and put into use in 2012. Besides inheriting the technically compatible with BDS-1, BDS-2 also added a passive positioning scheme to provide users in the Asia-Pacific regions with positioning, velocity measurement, timing and short message communication services. BDS-3 construction was started from 2009 and fully completed in 2020. On the basis of BDS-2, BDS-3 further improves services performance and expands services functions.
