The Ionospheric Correction Processor for SBAS and QZSS L1-SAIF

Takeyasu Sakai, Takayuki Yoshihara, Sonosuke Fukushima, Ken Ito

Abstract:	Japan has been operating its own SBAS (satellite-based augmentation system) system named MSAS (MTSAT satellite-based augmentation system) since 2007. QZSS (quasi-zenith satellite system) is another Japanese satellite navigation program with a regional service coverage planned to be launched by 2010. Both systems would broadcast GPS augmentation messages on the GPS L1 frequency based on SBAS standards, and offer wide-area differential corrections available over Japanese territory. QZSS SBAS signal on L1 frequency is called L1-SAIF. Ionospheric delay is now recognized as a major error source for satellite navigation systems. Therefore, MSAS and QZSS both based on the SBAS standard have a capability to make a correction to ionospheric delay effects on GNSS in addition to satellite clock and orbit. They would broadcast users the vertical ionospheric delays in meters at the grid points (IGP; ionospheric grid point) located at every five degrees in latitude and longitude. It is essential to generate and broadcast the better ionospheric correction information to improve the performance of the wide-area differential GPS system, such as SBAS. One possible way to improve ionospheric correction is increasing monitor stations used for generation of ionospheric correction information. In order to investigate such a way, the authors have developed specialized Ionospheric Correction Processor (ICP), because the existing correction processor for MSAS and L1-SAIF does not have a capability to input measurements from such a number of monitor stations. The ICP has been integrated into the QZSS L1-SAIF master station (L1SMS) so that it runs with the L1-SAIF message generator (L1SMG). The initial results of realtime operation test demonstrate developed ICP is fully functional and has a capability to improve ionospheric correction performance so that the target accuracy of 1 meter is likely achievable even for vertical direction in the Southern Region during nominal ionospheric condition. The ICP could also be applied to SBAS as an external correction source so that the ionospheric correction performace would be improved.
Published in:	Proceedings of the 2009 International Technical Meeting of The Institute of Navigation January 26 - 28, 2009 Disney's Paradise Pier Hotel Anaheim, CA
Pages:	312 - 323
Cite this article:	Sakai, Takeyasu, Yoshihara, Takayuki, Fukushima, Sonosuke, Ito, Ken, "The Ionospheric Correction Processor for SBAS and QZSS L1-SAIF," Proceedings of the 2009 International Technical Meeting of The Institute of Navigation, Anaheim, CA, January 2009, pp. 312-323.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In