BeiDou Navigation Satellite System

System
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(1) Overview

The BeiDou Navigation Satellite System (BDS) has been independently constructed and operated by China with an eye to the needs of the country’s national security and economic and social development. As a space infrastructure of national significance, BDS provides all-time, all-weather and high-accuracy positioning, navigation and timing services to global users. 

Along with the development of the BDS service capability, related products have been widely applied in communication, marine fishery, hydrological monitoring, weather forecasting, surveying, mapping and geographic information, forest fire prevention, time synchronization for communication systems, power dispatching, disaster mitigation and relief, emergency search and rescue, and other fields. These products have been gradually penetrating every aspect of social production and people’s life, injecting new vitality into the global economy and social development. 

Navigation satellite systems are public resources shared by the whole globe, and multi-system compatibility and interoperability have become a trend. China applies the principle that “BDS is developed by China, and dedicated to the world”, serving the development of the Silk Road Economic Belt, and actively pushing forward international cooperation related to BDS. As BDS joins hands with other navigation satellite systems, China will work with all other countries, regions and international organizations to promote global satellite navigation development and make BDS further serve the world and benefit mankind. 

(2) Development Path

In the late 20rd century, China started to explore a path to develop a navigation satellite system suitable for its national conditions, and gradually formulated a three-step development strategy: completing the construction of BDS-1 and provide services to the whole country by the end of 2000; completing the construction of BDS-2 and provide services to the Asia-Pacific region by the end of 2012; and to complete the construction of BDS-3 and provide services worldwide around 2020. 

(3) Development Goals

The BDS development is aimed to build a world-class navigation satellite system to meet the needs of the country’s national security as well as economic and social development; to provide continuous, stable and reliable services for global users; to develop BDS-related industries to support China’s economic and social development, as well as improvement of people’s living standards; and to enhance international cooperation to share the fruits of development in the field of satellite navigation, increasing the comprehensive application benefits of Global Navigation Satellite System (GNSS).

(4) Development Principles

 China upholds the principles of “independence, openness, compatibility and gradualness” in the BDS construction and development. 

·Independence refers to uphold independent construction, development and operation of BDS, and to acquire the capability to independently provide satellite navigation services to global users. 

·Openness refers to provide open satellite navigation services free of charge, and to encourage all-scale, multi-level and high-quality international cooperation and exchange. 

·Compatibility refers to enhance the BDS compatibility and interoperability with other navigation satellite systems, and to encourage international collaborations and exchanges, so as to provide better services to users. 

·Gradualness refers to carry out the BDS development in a phased approach, to enhance the BDS service performance, and to boost the development of satellite navigation industries in a comprehensive, coordinated and sustainable manner. 

(5) Development Plan

Currently, BDS-3 is under construction. According the overall plan, it will provide basic services to the countries along the Belt and Road and the neighboring regions by 2018, and to complete the constellation deployment with the launch of 35 satellites by 2020 to provide services to global users.

 

(6) Main Composition of BDS

 BDS is mainly comprised of three segments: space segment, ground segment and user segment.

·The BDS space segment. The BDS space segment is a hybrid navigation constellation consisting of GEO, IGSO and MEO satellites. 

·The BDS ground segment. The BDS ground segment consists of various ground stations, including master control stations, time synchronization and uplink stations, as well as monitoring stations. 

·The BDS user segment. The BDS user segment consists of various kinds of BDS basic products, including chips, modules and antennae, as well as terminals, application systems and application services, which may be compatible with other systems. 

(7) BDS Characteristics

The BDS development follows a model of developing regional service capacities, then gradually extending the service globally. This practice has enriched the development models for navigation satellite systems worldwide.

BDS possesses the following characteristics: First, its space segment is a hybrid constellation consisting of satellites in three kinds of orbits. In comparison with other navigation satellite systems, BDS operates more satellites in high orbits to offer better anti-shielding capabilities, which is particularly observable in terms of performance in the low-latitude areas. Second, BDS provides navigation signals of multiple frequencies, and is able to improve service accuracy by using combined multi-frequency signals. Third, BDS integrates navigation and communication capabilities for the first time, and has five major functions – real-time navigation, rapid positioning, precise timing, location reporting and short message communication services. 

(8) Services

Currently, B1I and B2I open service signals are being broadcasted by the operating BDS-2 satellites to provide open services to the Asia-Pacific region free of charge. The services cover an area extending 55°N-55°S and 55°E-180°E, with positioning accuracy better than 10 meters, velocity measurement accuracy better than 0.2 meter per second, and timing accuracy better than 50 nanoseconds.

An navigation satellite systems is not only the common wealth of the development of mankind, but also a space infrastructure which can provide all-time precise time and space information. It promotes the development of emerging industrial clusters that are technology- and knowledge-intensive with huge growth potentials and sound comprehensive benefits, thus becoming critical for national security, economic and social development, and increasingly improving the people’s production and living activities. 

China will continue its BDS construction, improve the system performance, and fulfill its service commitments. It will persist in opening up and cooperation, promote the popularization in this field, strive to advance satellite navigation applications worldwide, and make satellite navigation better benefit the wellbeing of the people and the progress of mankind.