Project Brief

      Aiming at the internationalization of Beidou System and the urgent needs of China's space system for ionospheric environmental monitoring, fully tap the technical features of Beidou and Galileo, make breakthroughs in ionospheric real-time refined detection technology integrating Beidou and Galileo, and develop a space ionospheric real-time monitoring and service platform. A series of real-time ionospheric products, including ionospheric TEC, three-dimensional electron density, perturbation, etc., will be formed, and applications for navigation and positioning, shortwave communication, scientific research and other fields will be verified.

      Relying on the jointly developed ionospheric real-time monitoring and service platform, the ionospheric Analysis Center of the Chinese Academy of Sciences, the most authoritative IGS organization in the world, has been established. To lead the formulation of global ionospheric IGS-SSR data standard, and promote the inclusion of Beidou Ionosphere into international IGS data standard; To develop the Beidou /Galileo/GPS Integrated Space Atmosphere Sounding equipment (BDSmart), and realize the first joint ionospheric observation between Beidou /Galileo and low frequency Radio Astronomy Telescope (LOFAR); Based on high-precision ionospheric data, the team cooperated with real-time satellite clock orbit and other products to jointly promote the application of "Beidou +Galileo" high-precision positioning in autonomous driving, space remote sensing, smart phones and other fields. Beidou Ionospheric international cooperation achievements, and selected in the national "13th Five-Year Plan" scientific and technological innovation achievements exhibition.



Project Processes

In August 2019, ARTERMIS, an International Collaboration project on the Satellite-Navigation Ionosphere, was launched.

01

In September 2019, the International Conference on the Ionosphere of COSPAR Beacons was organized in Poland

02

In October 2019, the first IGS Ionospheric Working Group Forum was held in Beijing

03

In October 2020, jointly promoted the development of IGS real-time ionospheric products IGS-SSR data format

04

In November 2020, the Joint Ionospheric Observation Station of LOFAR and Beidou /Galileo was completed in Olszeddin, Poland

05

In August 2021, jointly developed ionospheric real-time monitoring and service platform and built IGS real-time Analysis Center (code CAS).

06
Project Achievement


      A unified definition and accurate estimation method of Beidou /GNSS signal deviation is proposed. Based on the structural characteristics of signals of different navigation systems and noise levels of different types of observations, basic frequency points with relatively stable performance and basic observations of each frequency point are effectively selected, and signal deviation parameters for each independent observation type are defined. To achieve the unified expression of multi-mode and multi-frequency Beidou /GNSS signal deviation parameters; The effective observation information of multi-mode and multi-frequency GNSS was fully mined, the rigorous mathematical model of signal deviation and ionospheric parameter estimation and the stable reference of signal deviation parameters were constructed, and a new method of unified definition and accurate estimation of multi-mode and multi-frequency navigation signal deviation was formed, taking full account of the characteristics of Beidou signal, and the unified broadcasting format of deviation products for real-time applications was designed.
      Relevant achievements have been published in journals such as Journal of Geodesy. It is the first team in the world to publish pseudo-distance deviation data products, with the most complete types of data products (involving 5 systems and more than 40 types). The routine products released by the team have been used by more than 10 institutions at home and abroad, such as French Center for Space Research and European GMV Company.


      Ionospheric gradient and scintillation effect are one of the difficult problems that restrict the accurate and reliable service of Beidou /GNSS. Aiming at the ionospheric TEC change rate index ROTI, an adaptive window adjustment strategy and an optimal parameter calculation strategy were designed to make full use of regional real-time GNSS high frequency observation data, and a ROTI index spatial meshless method based on IDW was established on the basis of real-time ROTI calculation of satellite sight direction at each reference station. Achieve regional/global real-time fine monitoring of ionospheric gradient effects.
      Aiming at the ionospheric phase and amplitude scintillation index, a detrending perturbation detection algorithm based on high frequency ionospheric observations is proposed. On the basis of calculating the discretized ionospheric phase and amplitude scintillation index, a spatial mesh-based scintillation index method based on IDW is established to realize the regional/global real-time precise monitoring of ionospheric scintillation effect


      In view of the characteristics of satellite-borne GNSS, altimeter satellite and DORIS and other observational data, the rapid extraction method of ionospheric TEC and its rate of change was redesigned. In particular, the corresponding data quality control strategy was designed to ensure the accuracy of ionospheric key parameter extraction. Secondly, considering the different heights of different observation platforms, the physical meaning of ionospheric TEC is quite different. It is necessary to estimate the systematic deviation between different types of ionospheric observations synchronously, and analyze the variation characteristics of the deviation in time and space statistically. On this basis, based on the main processing idea of "modeling + prediction", the iterative fusion processing method of non-synchronous ionospheric observation data (including ionospheric observation information such as DORIS, satellite-borne GNSS, altimeter satellite, ground-based GNSS, etc.) was established by adopting the strategy of parallel processing of multiple method equations. Real-time modeling and processing of global ionospheric TEC correction information and quality identification information are realized.
      Relevant achievements have been published in journals such as Journal of Geodesy. As one of the first analysis centers to provide global real-time ionospheric products to IGS, it led the formulation of IGS real-time ionospheric IGS-SSR data standard.


      By comprehensively utilizing ground-based Beidou /Galileo/GPS data, ionospheric altimeter observation data, spaceborne ionospheric occultation observation and other data, the three-dimensional variation structure of global and regional ionospheric structure is obtained through multi-source data fusion and ionospheric model assimilation. The assimilated IRI ionospheric model provides a "virtual observation" for the subsequent ionospheric inversion based on computer imaging through near real-time prediction. On this basis, an adaptive Beidou /GNSS multi-mode ionospheric inversion model is constructed considering the actual physical changes of the ionosphere, so as to control and reduce the discomfort of the ionospheric imaging system. We have realized the tomographic inversion of the three-dimensional structure of ionospheric electron density, developed the real-time data processing software of global and regional ionospheric three-dimensional structure inversion, and realized the service application of the real-time product of ionospheric three-dimensional electron density for frequency selection of shortwave communication.


      On the basis of breakthroughs in key technologies such as accurate capture and tracking of navigation signals, independent calibration of multi-system signal deviations, real-time synchronous and accurate inversion of space ionosphere and troposphere parameters, innovative research on key technologies and principle prototype of integrated fine monitoring of space atmosphere (ionosphere and troposphere) has been carried out, and online real-time joint monitoring of ionosphere and troposphere parameters has been realized. While significantly improving the intensification degree and monitoring efficiency of satellite navigation ionosphere and troposphere sounding equipment, and greatly reducing the equipment cost of large-scale networking, it can directly provide portable and low-cost equipment for the construction of refined sounding network of space atmosphere (troposphere + ionosphere) based on the Beidou system. Thus, it will greatly promote the application of Beidou in the field of meteorology and space weather.


      The Beidou /GNSS real-time ionospheric monitoring and service system will be established to provide regional/global real-time ionospheric TEC and electron density products based on the service system. Based on the application verification of frequency selection for shortwave communication, the spatial variation characteristics of the ionosphere under different background conditions will be explored. The regional variations of the ionosphere during space weather events such as magnetic storms and nighttime intensification are revealed. The response of the ionosphere to atmospheric fluctuations and ionospheric dynamics is further understood from the perspective of spatial variation characteristics, and a new understanding of the ionospheric climate and weather characteristics and its driving mechanism is formed.

1Analysis Center

1Technical standard

10 Academic Papers

10 Invention Patents

3Achievement Reward

1Software System