With the Beidou satellite navigation system beginning to provide formal services and the continued development of Galileo system, the world's satellite navigation have stepped into a new era that four major satellite navigation systems (BD, GPS, GLONASS, Galileo) cooperated with each other. China has raised the international action of GNSS monitoring and assessment and started the project of establishing iGMAS (international GNSS Monitoring & Assessment System), which aims to realize Multi-satellite navigation system compatible interoperability and ensure the Multi - satellite navigation systems providing much more convenience.iGMAS aims to build a globally distributed GNSS signal tracking network by using multiple GNSS high-precision receivers and high-gain omnidirectional antennas. The data from several monitoring and evaluation stations are aggregated into the analysis center for data processing and multiple system Monitor and evaluate information to monitor the service performance and signal quality of GNSS systems and serve GNSS users worldwide. Global users through the Internet can not only open access to the GNSS system monitoring, evaluation of service information, but also can get some high-precision data products, such as satellite precision track, precision clock error and other information. IGMAS on the one hand can monitor the evaluation of GNSS system open service performance, on the other hand can also promote the national GNSS system compatibility and interoperability. These efforts will undoubtedly improve and promote the sustainable development of the GNSS system itself.
iGMAS as a global continuous monitoring and evaluation system, Consists of about 30 tracking stations which were uniform distribution around the world, 3 data centers, 7 analysis centers, 1 monitoring and evaluation center, 1 comprehensive analysis and product distribution center, 1 running management control center and communication network. iGMAS is not only an information service platform for data collection, storage, analysis, management, publishing and so on. It also provides shared data and products for Beidou satellite navigation system, support technical test, monitoring and evaluation, scientific research and professional application.
At present, China's iGMAS has begun to take shape, BD / GPS / GLONASS / Galileo four system tracking station has begun to test running, through the observation of these data comprehensive analysis, analysis and comparison, we have different satellite navigation system service performance evaluation, got some preliminary results. A global tracking station monitoring network is under construction, more research institutions to join, further evaluation of satellite navigation system monitoring and evaluation parameters and in-depth analysis of global data will be conducive to the objective evaluation of the satellite navigation system performance, to provide a useful reference for users around the world.