Development of satellite-based positioning and navigation technology has greatly reformed conventional spatial determination practices and enabled advancement of the digital infrastructure in China. This kind of progress is continuing with the improvement of related techniques.
Development of satellite-based positioning and navigation technology has greatly reformed conventional spatial determination practices and enabled advancement of the digital infrastructure in China. This kind of progress is continuing with the improvement of related techniques.
This article will provide an update on China’s GNSS-related activities in recent years, including research on novel positioning approaches, collaborations between China and international sectors, and, finally, some brief comments on the prospect for China’s Beidou navigation and positioning system.
China’s CORS Network
Beginning in 1990, the mode of continuously operating reference station (CORS) using GPS was first applied by NASA’s Jet Propulsion Laboratory (JPL) and MIT to the research of plate tectonics in southern California, USA. This innovation successfully helped geologists to deepen their understanding of seismic faults because more continuous spatial information can be obtained than ever before.
From 1997 to 2000, as a key state scientific project, the Crust Motion Observation Network of China (CMONOC) was implemented, composed of 25 CORS stations and 1,000 regional network stations. Very long baseline interferometry (VLBI) and satellite laser ranging (SLR) equipment was coupled in some of the CORS stations. Based on CMONOC, researchers achieved significant seismic motion results about continental plates. CORS has subsequently been employed by numerous agencies and organizations in China and has become popular in many fields, including guidance of aircraft similar to the U.S. Wide Area Augmentation System (WAAS) approach procedures.
In contrast to preliminary stages, evolution of networks and communications have enabled CORS to become a leading support component for the national temporal and spatial information infrastructure. CORS is now implemented at many of China’s main cities, such as Shenzhen, Chengdu, Beijing, Shanghai, and Guangzhou.
Among these, the Shenzhen CORS system was started in 1999 as a paradigm of comprehensive service network and spatial data infrastructure in China. The system was designed and implemented in a flexible form of network and wireless communication to perform a variety of positioning and navigation services in both real-time and postprocessing.
The project was jointly accomplished by the GNSS Engineering Research Center, Wuhan University, and Shenzhen Municipal Bureau of Land Resources and Housing Management. It is aimed at applications for surveying and mapping, urban planning, resource management, transportation monitoring, disaster prevention, and scientific research including meteorology and ionosphere scintillation.
In this way, the Shenzhen CORS network is acting to energize the booming economy of this young city. With rapid development of CORS construction in China, these stations are expected to operate within a standard national specification and to play vital roles in realization of the “digital city” in terms of real-time and precise positioning and navigation.
Based on CORS stations properly distributed throughout China, some of these facilities are aligned with stations installed with other spatial observing technologies such as SLR, VLBI and DORIS (Doppler Orbitography and Radio-positioning Integrated by Satellite, a system maintained by France). These sites are serving for satellite orbit determination and, when combined with multiple spatial technologies, have created a dynamic and multi-dimensional terrestrial reference frame for China.
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