Journal of Systems Engineering and Electronics ›› 2018, Vol. 29 ›› Issue (5): 908-917.doi: 10.21629/JSEE.2018.05.03

• Electronics Technology • Previous Articles     Next Articles

Impact of ionospheric irregularity on SBAS integrity: spatial threat modeling and improvement

Junjie BAO(), Rui LI(), Pan LIU*(), Zhigang HUANG()   

  • Received:2017-04-26 Online:2018-10-26 Published:2018-11-14
  • Contact: Pan LIU;;;
  • About author:BAO Junjie was born in 1989. She is a Ph.D. candidate in communications and information systems at School of Electronic and Information Engineering, Beihang University. Her current research is targeted on the technology of satellite-based augmentation system integrity algorithms, mainly ionospheric correction. E-mail:|LI Rui was born in 1976. He received his Ph.D. degree from Beihang University in 2006. He is now a senior engineer in the School of Electronic and Information Engineering, Beihang University. His main interests cover required navigation performance and global navigation satellite system augmentation technologies in satellite-based augmentation system, ground based augmentation system, and aircraft based augmentation system. E-mail: lee|LIU Pan was born in 1993. She received her M.S. degree from Beihang University in 2017. Her research interest focuses on the technology of ionospheric correction. E-mail:|HUANG Zhigang was born in 1962. He received his Ph.D. degree from Beihang University in 2004. He is currently a professor in the School of Electronics and Information Engineering, Beihang University. His research interests include integrity algorithms and related software for ground based augmentation system and satellite-based augmentation system. E-mail:
  • Supported by:
    the National Natural Science Foundation of China(41304024);This work was supported by the National Natural Science Foundation of China (41304024)


The ionosphere, as the largest and least predictable error source, its behavior cannot be observed at all places simultaneously. The confidence bound, called the grid ionospheric vertical error (GIVE), can only be determined with the aid of a threat model which is used to restrict the expected ionospheric behavior. However, the spatial threat model at present widespread used, which is based on fit radius and relative centroid metric (RCM), is too conservative or the resulting GIVEs will be too large and will reduce the availability of satellite-based augmentation system (SBAS). In this paper, layered two-dimensional parameters, the vertical direction double RCMs, are introduced based on the spatial variability of the ionosphere. Comparing with the traditional threat model, the experimental results show that the user ionospheric vertical error (UIVE) average reduction rate reaches 16%. And the 95% protection level of conterminous United States (CONUS) is 28%, even under disturbed days, which reaches about 5% reduction rates. The results show that the system service performance has been improved better.

Key words: ionospheric delay, spatial threat model, relative centroid metric (RCM), user ionospheric vertical error (UIVE)